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Subject[patch 03/10] Move kprobes to instrumentation/ and arch/*/instrumentation/
Consolidate the kprobes in the instrumentation directory.

- /instrumentation is compiled as a core-y
- Note : arch/*/instrumentation/kprobes.c is now compiled as a drivers-y. Was a
core-y before. It is caused by oprofile being a drivers-y.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Prasanna S Panchamukhi <prasanna@in.ibm.com>
CC: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
CC: David S. Miller <davem@davemloft.net>
---
Makefile | 3
arch/avr32/instrumentation/Makefile | 2
arch/avr32/instrumentation/kprobes.c | 268 ++++++++
arch/avr32/kernel/Makefile | 1
arch/avr32/kernel/kprobes.c | 268 --------
arch/ia64/instrumentation/Makefile | 2
arch/ia64/instrumentation/kprobes.c | 1027 +++++++++++++++++++++++++++++++
arch/ia64/kernel/kprobes.c | 1027 -------------------------------
arch/powerpc/instrumentation/Makefile | 2
arch/powerpc/instrumentation/kprobes.c | 559 +++++++++++++++++
arch/powerpc/kernel/kprobes.c | 559 -----------------
arch/s390/instrumentation/Makefile | 2
arch/s390/instrumentation/kprobes.c | 672 ++++++++++++++++++++
arch/s390/kernel/kprobes.c | 672 --------------------
arch/sparc64/instrumentation/Makefile | 2
arch/sparc64/instrumentation/kprobes.c | 487 +++++++++++++++
arch/sparc64/kernel/kprobes.c | 487 ---------------
arch/x86/instrumentation/Makefile | 6
arch/x86/instrumentation/kprobes_32.c | 763 +++++++++++++++++++++++
arch/x86/instrumentation/kprobes_64.c | 761 +++++++++++++++++++++++
arch/x86/kernel/Makefile_32 | 1
arch/x86/kernel/Makefile_64 | 1
arch/x86/kernel/kprobes_32.c | 763 -----------------------
arch/x86/kernel/kprobes_64.c | 761 -----------------------
instrumentation/Makefile | 2
instrumentation/kprobes.c | 1063 +++++++++++++++++++++++++++++++++
kernel/Makefile | 1
kernel/kprobes.c | 1063 ---------------------------------
28 files changed, 5620 insertions(+), 5605 deletions(-)

Index: linux-2.6-lttng.stable/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,1063 @@
+/*
+ * Kernel Probes (KProbes)
+ * kernel/kprobes.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ * Probes initial implementation (includes suggestions from
+ * Rusty Russell).
+ * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
+ * hlists and exceptions notifier as suggested by Andi Kleen.
+ * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ * interface to access function arguments.
+ * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
+ * exceptions notifier to be first on the priority list.
+ * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ * <prasanna@in.ibm.com> added function-return probes.
+ */
+#include <linux/kprobes.h>
+#include <linux/hash.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <linux/kallsyms.h>
+#include <linux/freezer.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/kdebug.h>
+
+#include <asm-generic/sections.h>
+#include <asm/cacheflush.h>
+#include <asm/errno.h>
+#include <asm/uaccess.h>
+
+#define KPROBE_HASH_BITS 6
+#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
+
+
+/*
+ * Some oddball architectures like 64bit powerpc have function descriptors
+ * so this must be overridable.
+ */
+#ifndef kprobe_lookup_name
+#define kprobe_lookup_name(name, addr) \
+ addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
+#endif
+
+static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
+static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
+
+/* NOTE: change this value only with kprobe_mutex held */
+static bool kprobe_enabled;
+
+DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
+DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
+static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
+
+#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
+/*
+ * kprobe->ainsn.insn points to the copy of the instruction to be
+ * single-stepped. x86_64, POWER4 and above have no-exec support and
+ * stepping on the instruction on a vmalloced/kmalloced/data page
+ * is a recipe for disaster
+ */
+#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+
+struct kprobe_insn_page {
+ struct hlist_node hlist;
+ kprobe_opcode_t *insns; /* Page of instruction slots */
+ char slot_used[INSNS_PER_PAGE];
+ int nused;
+ int ngarbage;
+};
+
+enum kprobe_slot_state {
+ SLOT_CLEAN = 0,
+ SLOT_DIRTY = 1,
+ SLOT_USED = 2,
+};
+
+static struct hlist_head kprobe_insn_pages;
+static int kprobe_garbage_slots;
+static int collect_garbage_slots(void);
+
+static int __kprobes check_safety(void)
+{
+ int ret = 0;
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
+ ret = freeze_processes();
+ if (ret == 0) {
+ struct task_struct *p, *q;
+ do_each_thread(p, q) {
+ if (p != current && p->state == TASK_RUNNING &&
+ p->pid != 0) {
+ printk("Check failed: %s is running\n",p->comm);
+ ret = -1;
+ goto loop_end;
+ }
+ } while_each_thread(p, q);
+ }
+loop_end:
+ thaw_processes();
+#else
+ synchronize_sched();
+#endif
+ return ret;
+}
+
+/**
+ * get_insn_slot() - Find a slot on an executable page for an instruction.
+ * We allocate an executable page if there's no room on existing ones.
+ */
+kprobe_opcode_t __kprobes *get_insn_slot(void)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos;
+
+ retry:
+ hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
+ if (kip->nused < INSNS_PER_PAGE) {
+ int i;
+ for (i = 0; i < INSNS_PER_PAGE; i++) {
+ if (kip->slot_used[i] == SLOT_CLEAN) {
+ kip->slot_used[i] = SLOT_USED;
+ kip->nused++;
+ return kip->insns + (i * MAX_INSN_SIZE);
+ }
+ }
+ /* Surprise! No unused slots. Fix kip->nused. */
+ kip->nused = INSNS_PER_PAGE;
+ }
+ }
+
+ /* If there are any garbage slots, collect it and try again. */
+ if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
+ goto retry;
+ }
+ /* All out of space. Need to allocate a new page. Use slot 0. */
+ kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
+ if (!kip)
+ return NULL;
+
+ /*
+ * Use module_alloc so this page is within +/- 2GB of where the
+ * kernel image and loaded module images reside. This is required
+ * so x86_64 can correctly handle the %rip-relative fixups.
+ */
+ kip->insns = module_alloc(PAGE_SIZE);
+ if (!kip->insns) {
+ kfree(kip);
+ return NULL;
+ }
+ INIT_HLIST_NODE(&kip->hlist);
+ hlist_add_head(&kip->hlist, &kprobe_insn_pages);
+ memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
+ kip->slot_used[0] = SLOT_USED;
+ kip->nused = 1;
+ kip->ngarbage = 0;
+ return kip->insns;
+}
+
+/* Return 1 if all garbages are collected, otherwise 0. */
+static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
+{
+ kip->slot_used[idx] = SLOT_CLEAN;
+ kip->nused--;
+ if (kip->nused == 0) {
+ /*
+ * Page is no longer in use. Free it unless
+ * it's the last one. We keep the last one
+ * so as not to have to set it up again the
+ * next time somebody inserts a probe.
+ */
+ hlist_del(&kip->hlist);
+ if (hlist_empty(&kprobe_insn_pages)) {
+ INIT_HLIST_NODE(&kip->hlist);
+ hlist_add_head(&kip->hlist,
+ &kprobe_insn_pages);
+ } else {
+ module_free(NULL, kip->insns);
+ kfree(kip);
+ }
+ return 1;
+ }
+ return 0;
+}
+
+static int __kprobes collect_garbage_slots(void)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos, *next;
+
+ /* Ensure no-one is preepmted on the garbages */
+ if (check_safety() != 0)
+ return -EAGAIN;
+
+ hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
+ int i;
+ if (kip->ngarbage == 0)
+ continue;
+ kip->ngarbage = 0; /* we will collect all garbages */
+ for (i = 0; i < INSNS_PER_PAGE; i++) {
+ if (kip->slot_used[i] == SLOT_DIRTY &&
+ collect_one_slot(kip, i))
+ break;
+ }
+ }
+ kprobe_garbage_slots = 0;
+ return 0;
+}
+
+void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos;
+
+ hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
+ if (kip->insns <= slot &&
+ slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
+ int i = (slot - kip->insns) / MAX_INSN_SIZE;
+ if (dirty) {
+ kip->slot_used[i] = SLOT_DIRTY;
+ kip->ngarbage++;
+ } else {
+ collect_one_slot(kip, i);
+ }
+ break;
+ }
+ }
+
+ if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
+ collect_garbage_slots();
+}
+#endif
+
+/* We have preemption disabled.. so it is safe to use __ versions */
+static inline void set_kprobe_instance(struct kprobe *kp)
+{
+ __get_cpu_var(kprobe_instance) = kp;
+}
+
+static inline void reset_kprobe_instance(void)
+{
+ __get_cpu_var(kprobe_instance) = NULL;
+}
+
+/*
+ * This routine is called either:
+ * - under the kprobe_mutex - during kprobe_[un]register()
+ * OR
+ * - with preemption disabled - from arch/xxx/kernel/kprobes.c
+ */
+struct kprobe __kprobes *get_kprobe(void *addr)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct kprobe *p;
+
+ head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
+ hlist_for_each_entry_rcu(p, node, head, hlist) {
+ if (p->addr == addr)
+ return p;
+ }
+ return NULL;
+}
+
+/*
+ * Aggregate handlers for multiple kprobes support - these handlers
+ * take care of invoking the individual kprobe handlers on p->list
+ */
+static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe *kp;
+
+ list_for_each_entry_rcu(kp, &p->list, list) {
+ if (kp->pre_handler) {
+ set_kprobe_instance(kp);
+ if (kp->pre_handler(kp, regs))
+ return 1;
+ }
+ reset_kprobe_instance();
+ }
+ return 0;
+}
+
+static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
+ unsigned long flags)
+{
+ struct kprobe *kp;
+
+ list_for_each_entry_rcu(kp, &p->list, list) {
+ if (kp->post_handler) {
+ set_kprobe_instance(kp);
+ kp->post_handler(kp, regs, flags);
+ reset_kprobe_instance();
+ }
+ }
+}
+
+static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
+ int trapnr)
+{
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+
+ /*
+ * if we faulted "during" the execution of a user specified
+ * probe handler, invoke just that probe's fault handler
+ */
+ if (cur && cur->fault_handler) {
+ if (cur->fault_handler(cur, regs, trapnr))
+ return 1;
+ }
+ return 0;
+}
+
+static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+ int ret = 0;
+
+ if (cur && cur->break_handler) {
+ if (cur->break_handler(cur, regs))
+ ret = 1;
+ }
+ reset_kprobe_instance();
+ return ret;
+}
+
+/* Walks the list and increments nmissed count for multiprobe case */
+void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
+{
+ struct kprobe *kp;
+ if (p->pre_handler != aggr_pre_handler) {
+ p->nmissed++;
+ } else {
+ list_for_each_entry_rcu(kp, &p->list, list)
+ kp->nmissed++;
+ }
+ return;
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
+ struct hlist_head *head)
+{
+ /* remove rp inst off the rprobe_inst_table */
+ hlist_del(&ri->hlist);
+ if (ri->rp) {
+ /* remove rp inst off the used list */
+ hlist_del(&ri->uflist);
+ /* put rp inst back onto the free list */
+ INIT_HLIST_NODE(&ri->uflist);
+ hlist_add_head(&ri->uflist, &ri->rp->free_instances);
+ } else
+ /* Unregistering */
+ hlist_add_head(&ri->hlist, head);
+}
+
+struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
+{
+ return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
+}
+
+/*
+ * This function is called from finish_task_switch when task tk becomes dead,
+ * so that we can recycle any function-return probe instances associated
+ * with this task. These left over instances represent probed functions
+ * that have been called but will never return.
+ */
+void __kprobes kprobe_flush_task(struct task_struct *tk)
+{
+ struct kretprobe_instance *ri;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags = 0;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(tk);
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task == tk)
+ recycle_rp_inst(ri, &empty_rp);
+ }
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+}
+
+static inline void free_rp_inst(struct kretprobe *rp)
+{
+ struct kretprobe_instance *ri;
+ struct hlist_node *pos, *next;
+
+ hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) {
+ hlist_del(&ri->uflist);
+ kfree(ri);
+ }
+}
+
+/*
+ * Keep all fields in the kprobe consistent
+ */
+static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
+{
+ memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
+ memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
+}
+
+/*
+* Add the new probe to old_p->list. Fail if this is the
+* second jprobe at the address - two jprobes can't coexist
+*/
+static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
+{
+ if (p->break_handler) {
+ if (old_p->break_handler)
+ return -EEXIST;
+ list_add_tail_rcu(&p->list, &old_p->list);
+ old_p->break_handler = aggr_break_handler;
+ } else
+ list_add_rcu(&p->list, &old_p->list);
+ if (p->post_handler && !old_p->post_handler)
+ old_p->post_handler = aggr_post_handler;
+ return 0;
+}
+
+/*
+ * Fill in the required fields of the "manager kprobe". Replace the
+ * earlier kprobe in the hlist with the manager kprobe
+ */
+static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+ copy_kprobe(p, ap);
+ flush_insn_slot(ap);
+ ap->addr = p->addr;
+ ap->pre_handler = aggr_pre_handler;
+ ap->fault_handler = aggr_fault_handler;
+ if (p->post_handler)
+ ap->post_handler = aggr_post_handler;
+ if (p->break_handler)
+ ap->break_handler = aggr_break_handler;
+
+ INIT_LIST_HEAD(&ap->list);
+ list_add_rcu(&p->list, &ap->list);
+
+ hlist_replace_rcu(&p->hlist, &ap->hlist);
+}
+
+/*
+ * This is the second or subsequent kprobe at the address - handle
+ * the intricacies
+ */
+static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
+ struct kprobe *p)
+{
+ int ret = 0;
+ struct kprobe *ap;
+
+ if (old_p->pre_handler == aggr_pre_handler) {
+ copy_kprobe(old_p, p);
+ ret = add_new_kprobe(old_p, p);
+ } else {
+ ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
+ if (!ap)
+ return -ENOMEM;
+ add_aggr_kprobe(ap, old_p);
+ copy_kprobe(ap, p);
+ ret = add_new_kprobe(ap, p);
+ }
+ return ret;
+}
+
+static int __kprobes in_kprobes_functions(unsigned long addr)
+{
+ if (addr >= (unsigned long)__kprobes_text_start &&
+ addr < (unsigned long)__kprobes_text_end)
+ return -EINVAL;
+ return 0;
+}
+
+static int __kprobes __register_kprobe(struct kprobe *p,
+ unsigned long called_from)
+{
+ int ret = 0;
+ struct kprobe *old_p;
+ struct module *probed_mod;
+
+ /*
+ * If we have a symbol_name argument look it up,
+ * and add it to the address. That way the addr
+ * field can either be global or relative to a symbol.
+ */
+ if (p->symbol_name) {
+ if (p->addr)
+ return -EINVAL;
+ kprobe_lookup_name(p->symbol_name, p->addr);
+ }
+
+ if (!p->addr)
+ return -EINVAL;
+ p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset);
+
+ if (!kernel_text_address((unsigned long) p->addr) ||
+ in_kprobes_functions((unsigned long) p->addr))
+ return -EINVAL;
+
+ p->mod_refcounted = 0;
+
+ /*
+ * Check if are we probing a module.
+ */
+ probed_mod = module_text_address((unsigned long) p->addr);
+ if (probed_mod) {
+ struct module *calling_mod = module_text_address(called_from);
+ /*
+ * We must allow modules to probe themself and in this case
+ * avoid incrementing the module refcount, so as to allow
+ * unloading of self probing modules.
+ */
+ if (calling_mod && calling_mod != probed_mod) {
+ if (unlikely(!try_module_get(probed_mod)))
+ return -EINVAL;
+ p->mod_refcounted = 1;
+ } else
+ probed_mod = NULL;
+ }
+
+ p->nmissed = 0;
+ mutex_lock(&kprobe_mutex);
+ old_p = get_kprobe(p->addr);
+ if (old_p) {
+ ret = register_aggr_kprobe(old_p, p);
+ goto out;
+ }
+
+ ret = arch_prepare_kprobe(p);
+ if (ret)
+ goto out;
+
+ INIT_HLIST_NODE(&p->hlist);
+ hlist_add_head_rcu(&p->hlist,
+ &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
+
+ if (kprobe_enabled)
+ arch_arm_kprobe(p);
+
+out:
+ mutex_unlock(&kprobe_mutex);
+
+ if (ret && probed_mod)
+ module_put(probed_mod);
+ return ret;
+}
+
+int __kprobes register_kprobe(struct kprobe *p)
+{
+ return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kprobe(struct kprobe *p)
+{
+ struct module *mod;
+ struct kprobe *old_p, *list_p;
+ int cleanup_p;
+
+ mutex_lock(&kprobe_mutex);
+ old_p = get_kprobe(p->addr);
+ if (unlikely(!old_p)) {
+ mutex_unlock(&kprobe_mutex);
+ return;
+ }
+ if (p != old_p) {
+ list_for_each_entry_rcu(list_p, &old_p->list, list)
+ if (list_p == p)
+ /* kprobe p is a valid probe */
+ goto valid_p;
+ mutex_unlock(&kprobe_mutex);
+ return;
+ }
+valid_p:
+ if (old_p == p ||
+ (old_p->pre_handler == aggr_pre_handler &&
+ p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
+ /*
+ * Only probe on the hash list. Disarm only if kprobes are
+ * enabled - otherwise, the breakpoint would already have
+ * been removed. We save on flushing icache.
+ */
+ if (kprobe_enabled)
+ arch_disarm_kprobe(p);
+ hlist_del_rcu(&old_p->hlist);
+ cleanup_p = 1;
+ } else {
+ list_del_rcu(&p->list);
+ cleanup_p = 0;
+ }
+
+ mutex_unlock(&kprobe_mutex);
+
+ synchronize_sched();
+ if (p->mod_refcounted) {
+ mod = module_text_address((unsigned long)p->addr);
+ if (mod)
+ module_put(mod);
+ }
+
+ if (cleanup_p) {
+ if (p != old_p) {
+ list_del_rcu(&p->list);
+ kfree(old_p);
+ }
+ arch_remove_kprobe(p);
+ } else {
+ mutex_lock(&kprobe_mutex);
+ if (p->break_handler)
+ old_p->break_handler = NULL;
+ if (p->post_handler){
+ list_for_each_entry_rcu(list_p, &old_p->list, list){
+ if (list_p->post_handler){
+ cleanup_p = 2;
+ break;
+ }
+ }
+ if (cleanup_p == 0)
+ old_p->post_handler = NULL;
+ }
+ mutex_unlock(&kprobe_mutex);
+ }
+}
+
+static struct notifier_block kprobe_exceptions_nb = {
+ .notifier_call = kprobe_exceptions_notify,
+ .priority = 0x7fffffff /* we need to be notified first */
+};
+
+unsigned long __weak arch_deref_entry_point(void *entry)
+{
+ return (unsigned long)entry;
+}
+
+int __kprobes register_jprobe(struct jprobe *jp)
+{
+ unsigned long addr = arch_deref_entry_point(jp->entry);
+
+ if (!kernel_text_address(addr))
+ return -EINVAL;
+
+ /* Todo: Verify probepoint is a function entry point */
+ jp->kp.pre_handler = setjmp_pre_handler;
+ jp->kp.break_handler = longjmp_break_handler;
+
+ return __register_kprobe(&jp->kp,
+ (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_jprobe(struct jprobe *jp)
+{
+ unregister_kprobe(&jp->kp);
+}
+
+#ifdef ARCH_SUPPORTS_KRETPROBES
+
+/*
+ * This kprobe pre_handler is registered with every kretprobe. When probe
+ * hits it will set up the return probe.
+ */
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+ struct pt_regs *regs)
+{
+ struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+ unsigned long flags = 0;
+
+ /*TODO: consider to only swap the RA after the last pre_handler fired */
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ if (!hlist_empty(&rp->free_instances)) {
+ struct kretprobe_instance *ri;
+
+ ri = hlist_entry(rp->free_instances.first,
+ struct kretprobe_instance, uflist);
+ ri->rp = rp;
+ ri->task = current;
+ arch_prepare_kretprobe(ri, regs);
+
+ /* XXX(hch): why is there no hlist_move_head? */
+ hlist_del(&ri->uflist);
+ hlist_add_head(&ri->uflist, &ri->rp->used_instances);
+ hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task));
+ } else
+ rp->nmissed++;
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ return 0;
+}
+
+int __kprobes register_kretprobe(struct kretprobe *rp)
+{
+ int ret = 0;
+ struct kretprobe_instance *inst;
+ int i;
+ void *addr = rp->kp.addr;
+
+ if (kretprobe_blacklist_size) {
+ if (addr == NULL)
+ kprobe_lookup_name(rp->kp.symbol_name, addr);
+ addr += rp->kp.offset;
+
+ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+ if (kretprobe_blacklist[i].addr == addr)
+ return -EINVAL;
+ }
+ }
+
+ rp->kp.pre_handler = pre_handler_kretprobe;
+ rp->kp.post_handler = NULL;
+ rp->kp.fault_handler = NULL;
+ rp->kp.break_handler = NULL;
+
+ /* Pre-allocate memory for max kretprobe instances */
+ if (rp->maxactive <= 0) {
+#ifdef CONFIG_PREEMPT
+ rp->maxactive = max(10, 2 * NR_CPUS);
+#else
+ rp->maxactive = NR_CPUS;
+#endif
+ }
+ INIT_HLIST_HEAD(&rp->used_instances);
+ INIT_HLIST_HEAD(&rp->free_instances);
+ for (i = 0; i < rp->maxactive; i++) {
+ inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
+ if (inst == NULL) {
+ free_rp_inst(rp);
+ return -ENOMEM;
+ }
+ INIT_HLIST_NODE(&inst->uflist);
+ hlist_add_head(&inst->uflist, &rp->free_instances);
+ }
+
+ rp->nmissed = 0;
+ /* Establish function entry probe point */
+ if ((ret = __register_kprobe(&rp->kp,
+ (unsigned long)__builtin_return_address(0))) != 0)
+ free_rp_inst(rp);
+ return ret;
+}
+
+#else /* ARCH_SUPPORTS_KRETPROBES */
+
+int __kprobes register_kretprobe(struct kretprobe *rp)
+{
+ return -ENOSYS;
+}
+
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+
+#endif /* ARCH_SUPPORTS_KRETPROBES */
+
+void __kprobes unregister_kretprobe(struct kretprobe *rp)
+{
+ unsigned long flags;
+ struct kretprobe_instance *ri;
+ struct hlist_node *pos, *next;
+
+ unregister_kprobe(&rp->kp);
+
+ /* No race here */
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
+ ri->rp = NULL;
+ hlist_del(&ri->uflist);
+ }
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ free_rp_inst(rp);
+}
+
+static int __init init_kprobes(void)
+{
+ int i, err = 0;
+
+ /* FIXME allocate the probe table, currently defined statically */
+ /* initialize all list heads */
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ INIT_HLIST_HEAD(&kprobe_table[i]);
+ INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
+ }
+
+ if (kretprobe_blacklist_size) {
+ /* lookup the function address from its name */
+ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+ kprobe_lookup_name(kretprobe_blacklist[i].name,
+ kretprobe_blacklist[i].addr);
+ if (!kretprobe_blacklist[i].addr)
+ printk("kretprobe: lookup failed: %s\n",
+ kretprobe_blacklist[i].name);
+ }
+ }
+
+ /* By default, kprobes are enabled */
+ kprobe_enabled = true;
+
+ err = arch_init_kprobes();
+ if (!err)
+ err = register_die_notifier(&kprobe_exceptions_nb);
+
+ return err;
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
+ const char *sym, int offset,char *modname)
+{
+ char *kprobe_type;
+
+ if (p->pre_handler == pre_handler_kretprobe)
+ kprobe_type = "r";
+ else if (p->pre_handler == setjmp_pre_handler)
+ kprobe_type = "j";
+ else
+ kprobe_type = "k";
+ if (sym)
+ seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type,
+ sym, offset, (modname ? modname : " "));
+ else
+ seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr);
+}
+
+static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
+{
+ return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
+}
+
+static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ (*pos)++;
+ if (*pos >= KPROBE_TABLE_SIZE)
+ return NULL;
+ return pos;
+}
+
+static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
+{
+ /* Nothing to do */
+}
+
+static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct kprobe *p, *kp;
+ const char *sym = NULL;
+ unsigned int i = *(loff_t *) v;
+ unsigned long offset = 0;
+ char *modname, namebuf[128];
+
+ head = &kprobe_table[i];
+ preempt_disable();
+ hlist_for_each_entry_rcu(p, node, head, hlist) {
+ sym = kallsyms_lookup((unsigned long)p->addr, NULL,
+ &offset, &modname, namebuf);
+ if (p->pre_handler == aggr_pre_handler) {
+ list_for_each_entry_rcu(kp, &p->list, list)
+ report_probe(pi, kp, sym, offset, modname);
+ } else
+ report_probe(pi, p, sym, offset, modname);
+ }
+ preempt_enable();
+ return 0;
+}
+
+static struct seq_operations kprobes_seq_ops = {
+ .start = kprobe_seq_start,
+ .next = kprobe_seq_next,
+ .stop = kprobe_seq_stop,
+ .show = show_kprobe_addr
+};
+
+static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &kprobes_seq_ops);
+}
+
+static struct file_operations debugfs_kprobes_operations = {
+ .open = kprobes_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static void __kprobes enable_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct kprobe *p;
+ unsigned int i;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* If kprobes are already enabled, just return */
+ if (kprobe_enabled)
+ goto already_enabled;
+
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, node, head, hlist)
+ arch_arm_kprobe(p);
+ }
+
+ kprobe_enabled = true;
+ printk(KERN_INFO "Kprobes globally enabled\n");
+
+already_enabled:
+ mutex_unlock(&kprobe_mutex);
+ return;
+}
+
+static void __kprobes disable_all_kprobes(void)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct kprobe *p;
+ unsigned int i;
+
+ mutex_lock(&kprobe_mutex);
+
+ /* If kprobes are already disabled, just return */
+ if (!kprobe_enabled)
+ goto already_disabled;
+
+ kprobe_enabled = false;
+ printk(KERN_INFO "Kprobes globally disabled\n");
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+ head = &kprobe_table[i];
+ hlist_for_each_entry_rcu(p, node, head, hlist) {
+ if (!arch_trampoline_kprobe(p))
+ arch_disarm_kprobe(p);
+ }
+ }
+
+ mutex_unlock(&kprobe_mutex);
+ /* Allow all currently running kprobes to complete */
+ synchronize_sched();
+ return;
+
+already_disabled:
+ mutex_unlock(&kprobe_mutex);
+ return;
+}
+
+/*
+ * XXX: The debugfs bool file interface doesn't allow for callbacks
+ * when the bool state is switched. We can reuse that facility when
+ * available
+ */
+static ssize_t read_enabled_file_bool(struct file *file,
+ char __user *user_buf, size_t count, loff_t *ppos)
+{
+ char buf[3];
+
+ if (kprobe_enabled)
+ buf[0] = '1';
+ else
+ buf[0] = '0';
+ buf[1] = '\n';
+ buf[2] = 0x00;
+ return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t write_enabled_file_bool(struct file *file,
+ const char __user *user_buf, size_t count, loff_t *ppos)
+{
+ char buf[32];
+ int buf_size;
+
+ buf_size = min(count, (sizeof(buf)-1));
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+
+ switch (buf[0]) {
+ case 'y':
+ case 'Y':
+ case '1':
+ enable_all_kprobes();
+ break;
+ case 'n':
+ case 'N':
+ case '0':
+ disable_all_kprobes();
+ break;
+ }
+
+ return count;
+}
+
+static struct file_operations fops_kp = {
+ .read = read_enabled_file_bool,
+ .write = write_enabled_file_bool,
+};
+
+static int __kprobes debugfs_kprobe_init(void)
+{
+ struct dentry *dir, *file;
+ unsigned int value = 1;
+
+ dir = debugfs_create_dir("kprobes", NULL);
+ if (!dir)
+ return -ENOMEM;
+
+ file = debugfs_create_file("list", 0444, dir, NULL,
+ &debugfs_kprobes_operations);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
+
+ file = debugfs_create_file("enabled", 0600, dir,
+ &value, &fops_kp);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+late_initcall(debugfs_kprobe_init);
+#endif /* CONFIG_DEBUG_FS */
+
+module_init(init_kprobes);
+
+EXPORT_SYMBOL_GPL(register_kprobe);
+EXPORT_SYMBOL_GPL(unregister_kprobe);
+EXPORT_SYMBOL_GPL(register_jprobe);
+EXPORT_SYMBOL_GPL(unregister_jprobe);
+#ifdef CONFIG_KPROBES
+EXPORT_SYMBOL_GPL(jprobe_return);
+#endif
+
+#ifdef CONFIG_KPROBES
+EXPORT_SYMBOL_GPL(register_kretprobe);
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+#endif
Index: linux-2.6-lttng.stable/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/kprobes.c 2007-10-29 09:51:06.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,1063 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- * kernel/kprobes.c
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- * Probes initial implementation (includes suggestions from
- * Rusty Russell).
- * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
- * hlists and exceptions notifier as suggested by Andi Kleen.
- * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- * interface to access function arguments.
- * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
- * exceptions notifier to be first on the priority list.
- * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
- * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
- * <prasanna@in.ibm.com> added function-return probes.
- */
-#include <linux/kprobes.h>
-#include <linux/hash.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/stddef.h>
-#include <linux/module.h>
-#include <linux/moduleloader.h>
-#include <linux/kallsyms.h>
-#include <linux/freezer.h>
-#include <linux/seq_file.h>
-#include <linux/debugfs.h>
-#include <linux/kdebug.h>
-
-#include <asm-generic/sections.h>
-#include <asm/cacheflush.h>
-#include <asm/errno.h>
-#include <asm/uaccess.h>
-
-#define KPROBE_HASH_BITS 6
-#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
-
-
-/*
- * Some oddball architectures like 64bit powerpc have function descriptors
- * so this must be overridable.
- */
-#ifndef kprobe_lookup_name
-#define kprobe_lookup_name(name, addr) \
- addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
-#endif
-
-static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
-static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
-
-/* NOTE: change this value only with kprobe_mutex held */
-static bool kprobe_enabled;
-
-DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
-DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
-static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
-
-#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
-/*
- * kprobe->ainsn.insn points to the copy of the instruction to be
- * single-stepped. x86_64, POWER4 and above have no-exec support and
- * stepping on the instruction on a vmalloced/kmalloced/data page
- * is a recipe for disaster
- */
-#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
-
-struct kprobe_insn_page {
- struct hlist_node hlist;
- kprobe_opcode_t *insns; /* Page of instruction slots */
- char slot_used[INSNS_PER_PAGE];
- int nused;
- int ngarbage;
-};
-
-enum kprobe_slot_state {
- SLOT_CLEAN = 0,
- SLOT_DIRTY = 1,
- SLOT_USED = 2,
-};
-
-static struct hlist_head kprobe_insn_pages;
-static int kprobe_garbage_slots;
-static int collect_garbage_slots(void);
-
-static int __kprobes check_safety(void)
-{
- int ret = 0;
-#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
- ret = freeze_processes();
- if (ret == 0) {
- struct task_struct *p, *q;
- do_each_thread(p, q) {
- if (p != current && p->state == TASK_RUNNING &&
- p->pid != 0) {
- printk("Check failed: %s is running\n",p->comm);
- ret = -1;
- goto loop_end;
- }
- } while_each_thread(p, q);
- }
-loop_end:
- thaw_processes();
-#else
- synchronize_sched();
-#endif
- return ret;
-}
-
-/**
- * get_insn_slot() - Find a slot on an executable page for an instruction.
- * We allocate an executable page if there's no room on existing ones.
- */
-kprobe_opcode_t __kprobes *get_insn_slot(void)
-{
- struct kprobe_insn_page *kip;
- struct hlist_node *pos;
-
- retry:
- hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
- if (kip->nused < INSNS_PER_PAGE) {
- int i;
- for (i = 0; i < INSNS_PER_PAGE; i++) {
- if (kip->slot_used[i] == SLOT_CLEAN) {
- kip->slot_used[i] = SLOT_USED;
- kip->nused++;
- return kip->insns + (i * MAX_INSN_SIZE);
- }
- }
- /* Surprise! No unused slots. Fix kip->nused. */
- kip->nused = INSNS_PER_PAGE;
- }
- }
-
- /* If there are any garbage slots, collect it and try again. */
- if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
- goto retry;
- }
- /* All out of space. Need to allocate a new page. Use slot 0. */
- kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
- if (!kip)
- return NULL;
-
- /*
- * Use module_alloc so this page is within +/- 2GB of where the
- * kernel image and loaded module images reside. This is required
- * so x86_64 can correctly handle the %rip-relative fixups.
- */
- kip->insns = module_alloc(PAGE_SIZE);
- if (!kip->insns) {
- kfree(kip);
- return NULL;
- }
- INIT_HLIST_NODE(&kip->hlist);
- hlist_add_head(&kip->hlist, &kprobe_insn_pages);
- memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
- kip->slot_used[0] = SLOT_USED;
- kip->nused = 1;
- kip->ngarbage = 0;
- return kip->insns;
-}
-
-/* Return 1 if all garbages are collected, otherwise 0. */
-static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
-{
- kip->slot_used[idx] = SLOT_CLEAN;
- kip->nused--;
- if (kip->nused == 0) {
- /*
- * Page is no longer in use. Free it unless
- * it's the last one. We keep the last one
- * so as not to have to set it up again the
- * next time somebody inserts a probe.
- */
- hlist_del(&kip->hlist);
- if (hlist_empty(&kprobe_insn_pages)) {
- INIT_HLIST_NODE(&kip->hlist);
- hlist_add_head(&kip->hlist,
- &kprobe_insn_pages);
- } else {
- module_free(NULL, kip->insns);
- kfree(kip);
- }
- return 1;
- }
- return 0;
-}
-
-static int __kprobes collect_garbage_slots(void)
-{
- struct kprobe_insn_page *kip;
- struct hlist_node *pos, *next;
-
- /* Ensure no-one is preepmted on the garbages */
- if (check_safety() != 0)
- return -EAGAIN;
-
- hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
- int i;
- if (kip->ngarbage == 0)
- continue;
- kip->ngarbage = 0; /* we will collect all garbages */
- for (i = 0; i < INSNS_PER_PAGE; i++) {
- if (kip->slot_used[i] == SLOT_DIRTY &&
- collect_one_slot(kip, i))
- break;
- }
- }
- kprobe_garbage_slots = 0;
- return 0;
-}
-
-void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
-{
- struct kprobe_insn_page *kip;
- struct hlist_node *pos;
-
- hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
- if (kip->insns <= slot &&
- slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
- int i = (slot - kip->insns) / MAX_INSN_SIZE;
- if (dirty) {
- kip->slot_used[i] = SLOT_DIRTY;
- kip->ngarbage++;
- } else {
- collect_one_slot(kip, i);
- }
- break;
- }
- }
-
- if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
- collect_garbage_slots();
-}
-#endif
-
-/* We have preemption disabled.. so it is safe to use __ versions */
-static inline void set_kprobe_instance(struct kprobe *kp)
-{
- __get_cpu_var(kprobe_instance) = kp;
-}
-
-static inline void reset_kprobe_instance(void)
-{
- __get_cpu_var(kprobe_instance) = NULL;
-}
-
-/*
- * This routine is called either:
- * - under the kprobe_mutex - during kprobe_[un]register()
- * OR
- * - with preemption disabled - from arch/xxx/kernel/kprobes.c
- */
-struct kprobe __kprobes *get_kprobe(void *addr)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe *p;
-
- head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
- hlist_for_each_entry_rcu(p, node, head, hlist) {
- if (p->addr == addr)
- return p;
- }
- return NULL;
-}
-
-/*
- * Aggregate handlers for multiple kprobes support - these handlers
- * take care of invoking the individual kprobe handlers on p->list
- */
-static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe *kp;
-
- list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->pre_handler) {
- set_kprobe_instance(kp);
- if (kp->pre_handler(kp, regs))
- return 1;
- }
- reset_kprobe_instance();
- }
- return 0;
-}
-
-static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
- unsigned long flags)
-{
- struct kprobe *kp;
-
- list_for_each_entry_rcu(kp, &p->list, list) {
- if (kp->post_handler) {
- set_kprobe_instance(kp);
- kp->post_handler(kp, regs, flags);
- reset_kprobe_instance();
- }
- }
-}
-
-static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
- int trapnr)
-{
- struct kprobe *cur = __get_cpu_var(kprobe_instance);
-
- /*
- * if we faulted "during" the execution of a user specified
- * probe handler, invoke just that probe's fault handler
- */
- if (cur && cur->fault_handler) {
- if (cur->fault_handler(cur, regs, trapnr))
- return 1;
- }
- return 0;
-}
-
-static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe *cur = __get_cpu_var(kprobe_instance);
- int ret = 0;
-
- if (cur && cur->break_handler) {
- if (cur->break_handler(cur, regs))
- ret = 1;
- }
- reset_kprobe_instance();
- return ret;
-}
-
-/* Walks the list and increments nmissed count for multiprobe case */
-void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
-{
- struct kprobe *kp;
- if (p->pre_handler != aggr_pre_handler) {
- p->nmissed++;
- } else {
- list_for_each_entry_rcu(kp, &p->list, list)
- kp->nmissed++;
- }
- return;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
- struct hlist_head *head)
-{
- /* remove rp inst off the rprobe_inst_table */
- hlist_del(&ri->hlist);
- if (ri->rp) {
- /* remove rp inst off the used list */
- hlist_del(&ri->uflist);
- /* put rp inst back onto the free list */
- INIT_HLIST_NODE(&ri->uflist);
- hlist_add_head(&ri->uflist, &ri->rp->free_instances);
- } else
- /* Unregistering */
- hlist_add_head(&ri->hlist, head);
-}
-
-struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
-{
- return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
-}
-
-/*
- * This function is called from finish_task_switch when task tk becomes dead,
- * so that we can recycle any function-return probe instances associated
- * with this task. These left over instances represent probed functions
- * that have been called but will never return.
- */
-void __kprobes kprobe_flush_task(struct task_struct *tk)
-{
- struct kretprobe_instance *ri;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags = 0;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(tk);
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task == tk)
- recycle_rp_inst(ri, &empty_rp);
- }
- spin_unlock_irqrestore(&kretprobe_lock, flags);
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
-}
-
-static inline void free_rp_inst(struct kretprobe *rp)
-{
- struct kretprobe_instance *ri;
- struct hlist_node *pos, *next;
-
- hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) {
- hlist_del(&ri->uflist);
- kfree(ri);
- }
-}
-
-/*
- * Keep all fields in the kprobe consistent
- */
-static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
-{
- memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
- memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
-}
-
-/*
-* Add the new probe to old_p->list. Fail if this is the
-* second jprobe at the address - two jprobes can't coexist
-*/
-static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
-{
- if (p->break_handler) {
- if (old_p->break_handler)
- return -EEXIST;
- list_add_tail_rcu(&p->list, &old_p->list);
- old_p->break_handler = aggr_break_handler;
- } else
- list_add_rcu(&p->list, &old_p->list);
- if (p->post_handler && !old_p->post_handler)
- old_p->post_handler = aggr_post_handler;
- return 0;
-}
-
-/*
- * Fill in the required fields of the "manager kprobe". Replace the
- * earlier kprobe in the hlist with the manager kprobe
- */
-static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
-{
- copy_kprobe(p, ap);
- flush_insn_slot(ap);
- ap->addr = p->addr;
- ap->pre_handler = aggr_pre_handler;
- ap->fault_handler = aggr_fault_handler;
- if (p->post_handler)
- ap->post_handler = aggr_post_handler;
- if (p->break_handler)
- ap->break_handler = aggr_break_handler;
-
- INIT_LIST_HEAD(&ap->list);
- list_add_rcu(&p->list, &ap->list);
-
- hlist_replace_rcu(&p->hlist, &ap->hlist);
-}
-
-/*
- * This is the second or subsequent kprobe at the address - handle
- * the intricacies
- */
-static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
- struct kprobe *p)
-{
- int ret = 0;
- struct kprobe *ap;
-
- if (old_p->pre_handler == aggr_pre_handler) {
- copy_kprobe(old_p, p);
- ret = add_new_kprobe(old_p, p);
- } else {
- ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
- if (!ap)
- return -ENOMEM;
- add_aggr_kprobe(ap, old_p);
- copy_kprobe(ap, p);
- ret = add_new_kprobe(ap, p);
- }
- return ret;
-}
-
-static int __kprobes in_kprobes_functions(unsigned long addr)
-{
- if (addr >= (unsigned long)__kprobes_text_start &&
- addr < (unsigned long)__kprobes_text_end)
- return -EINVAL;
- return 0;
-}
-
-static int __kprobes __register_kprobe(struct kprobe *p,
- unsigned long called_from)
-{
- int ret = 0;
- struct kprobe *old_p;
- struct module *probed_mod;
-
- /*
- * If we have a symbol_name argument look it up,
- * and add it to the address. That way the addr
- * field can either be global or relative to a symbol.
- */
- if (p->symbol_name) {
- if (p->addr)
- return -EINVAL;
- kprobe_lookup_name(p->symbol_name, p->addr);
- }
-
- if (!p->addr)
- return -EINVAL;
- p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset);
-
- if (!kernel_text_address((unsigned long) p->addr) ||
- in_kprobes_functions((unsigned long) p->addr))
- return -EINVAL;
-
- p->mod_refcounted = 0;
-
- /*
- * Check if are we probing a module.
- */
- probed_mod = module_text_address((unsigned long) p->addr);
- if (probed_mod) {
- struct module *calling_mod = module_text_address(called_from);
- /*
- * We must allow modules to probe themself and in this case
- * avoid incrementing the module refcount, so as to allow
- * unloading of self probing modules.
- */
- if (calling_mod && calling_mod != probed_mod) {
- if (unlikely(!try_module_get(probed_mod)))
- return -EINVAL;
- p->mod_refcounted = 1;
- } else
- probed_mod = NULL;
- }
-
- p->nmissed = 0;
- mutex_lock(&kprobe_mutex);
- old_p = get_kprobe(p->addr);
- if (old_p) {
- ret = register_aggr_kprobe(old_p, p);
- goto out;
- }
-
- ret = arch_prepare_kprobe(p);
- if (ret)
- goto out;
-
- INIT_HLIST_NODE(&p->hlist);
- hlist_add_head_rcu(&p->hlist,
- &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
-
- if (kprobe_enabled)
- arch_arm_kprobe(p);
-
-out:
- mutex_unlock(&kprobe_mutex);
-
- if (ret && probed_mod)
- module_put(probed_mod);
- return ret;
-}
-
-int __kprobes register_kprobe(struct kprobe *p)
-{
- return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
-}
-
-void __kprobes unregister_kprobe(struct kprobe *p)
-{
- struct module *mod;
- struct kprobe *old_p, *list_p;
- int cleanup_p;
-
- mutex_lock(&kprobe_mutex);
- old_p = get_kprobe(p->addr);
- if (unlikely(!old_p)) {
- mutex_unlock(&kprobe_mutex);
- return;
- }
- if (p != old_p) {
- list_for_each_entry_rcu(list_p, &old_p->list, list)
- if (list_p == p)
- /* kprobe p is a valid probe */
- goto valid_p;
- mutex_unlock(&kprobe_mutex);
- return;
- }
-valid_p:
- if (old_p == p ||
- (old_p->pre_handler == aggr_pre_handler &&
- p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
- /*
- * Only probe on the hash list. Disarm only if kprobes are
- * enabled - otherwise, the breakpoint would already have
- * been removed. We save on flushing icache.
- */
- if (kprobe_enabled)
- arch_disarm_kprobe(p);
- hlist_del_rcu(&old_p->hlist);
- cleanup_p = 1;
- } else {
- list_del_rcu(&p->list);
- cleanup_p = 0;
- }
-
- mutex_unlock(&kprobe_mutex);
-
- synchronize_sched();
- if (p->mod_refcounted) {
- mod = module_text_address((unsigned long)p->addr);
- if (mod)
- module_put(mod);
- }
-
- if (cleanup_p) {
- if (p != old_p) {
- list_del_rcu(&p->list);
- kfree(old_p);
- }
- arch_remove_kprobe(p);
- } else {
- mutex_lock(&kprobe_mutex);
- if (p->break_handler)
- old_p->break_handler = NULL;
- if (p->post_handler){
- list_for_each_entry_rcu(list_p, &old_p->list, list){
- if (list_p->post_handler){
- cleanup_p = 2;
- break;
- }
- }
- if (cleanup_p == 0)
- old_p->post_handler = NULL;
- }
- mutex_unlock(&kprobe_mutex);
- }
-}
-
-static struct notifier_block kprobe_exceptions_nb = {
- .notifier_call = kprobe_exceptions_notify,
- .priority = 0x7fffffff /* we need to be notified first */
-};
-
-unsigned long __weak arch_deref_entry_point(void *entry)
-{
- return (unsigned long)entry;
-}
-
-int __kprobes register_jprobe(struct jprobe *jp)
-{
- unsigned long addr = arch_deref_entry_point(jp->entry);
-
- if (!kernel_text_address(addr))
- return -EINVAL;
-
- /* Todo: Verify probepoint is a function entry point */
- jp->kp.pre_handler = setjmp_pre_handler;
- jp->kp.break_handler = longjmp_break_handler;
-
- return __register_kprobe(&jp->kp,
- (unsigned long)__builtin_return_address(0));
-}
-
-void __kprobes unregister_jprobe(struct jprobe *jp)
-{
- unregister_kprobe(&jp->kp);
-}
-
-#ifdef ARCH_SUPPORTS_KRETPROBES
-
-/*
- * This kprobe pre_handler is registered with every kretprobe. When probe
- * hits it will set up the return probe.
- */
-static int __kprobes pre_handler_kretprobe(struct kprobe *p,
- struct pt_regs *regs)
-{
- struct kretprobe *rp = container_of(p, struct kretprobe, kp);
- unsigned long flags = 0;
-
- /*TODO: consider to only swap the RA after the last pre_handler fired */
- spin_lock_irqsave(&kretprobe_lock, flags);
- if (!hlist_empty(&rp->free_instances)) {
- struct kretprobe_instance *ri;
-
- ri = hlist_entry(rp->free_instances.first,
- struct kretprobe_instance, uflist);
- ri->rp = rp;
- ri->task = current;
- arch_prepare_kretprobe(ri, regs);
-
- /* XXX(hch): why is there no hlist_move_head? */
- hlist_del(&ri->uflist);
- hlist_add_head(&ri->uflist, &ri->rp->used_instances);
- hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task));
- } else
- rp->nmissed++;
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- return 0;
-}
-
-int __kprobes register_kretprobe(struct kretprobe *rp)
-{
- int ret = 0;
- struct kretprobe_instance *inst;
- int i;
- void *addr = rp->kp.addr;
-
- if (kretprobe_blacklist_size) {
- if (addr == NULL)
- kprobe_lookup_name(rp->kp.symbol_name, addr);
- addr += rp->kp.offset;
-
- for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
- if (kretprobe_blacklist[i].addr == addr)
- return -EINVAL;
- }
- }
-
- rp->kp.pre_handler = pre_handler_kretprobe;
- rp->kp.post_handler = NULL;
- rp->kp.fault_handler = NULL;
- rp->kp.break_handler = NULL;
-
- /* Pre-allocate memory for max kretprobe instances */
- if (rp->maxactive <= 0) {
-#ifdef CONFIG_PREEMPT
- rp->maxactive = max(10, 2 * NR_CPUS);
-#else
- rp->maxactive = NR_CPUS;
-#endif
- }
- INIT_HLIST_HEAD(&rp->used_instances);
- INIT_HLIST_HEAD(&rp->free_instances);
- for (i = 0; i < rp->maxactive; i++) {
- inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
- if (inst == NULL) {
- free_rp_inst(rp);
- return -ENOMEM;
- }
- INIT_HLIST_NODE(&inst->uflist);
- hlist_add_head(&inst->uflist, &rp->free_instances);
- }
-
- rp->nmissed = 0;
- /* Establish function entry probe point */
- if ((ret = __register_kprobe(&rp->kp,
- (unsigned long)__builtin_return_address(0))) != 0)
- free_rp_inst(rp);
- return ret;
-}
-
-#else /* ARCH_SUPPORTS_KRETPROBES */
-
-int __kprobes register_kretprobe(struct kretprobe *rp)
-{
- return -ENOSYS;
-}
-
-static int __kprobes pre_handler_kretprobe(struct kprobe *p,
- struct pt_regs *regs)
-{
- return 0;
-}
-
-#endif /* ARCH_SUPPORTS_KRETPROBES */
-
-void __kprobes unregister_kretprobe(struct kretprobe *rp)
-{
- unsigned long flags;
- struct kretprobe_instance *ri;
- struct hlist_node *pos, *next;
-
- unregister_kprobe(&rp->kp);
-
- /* No race here */
- spin_lock_irqsave(&kretprobe_lock, flags);
- hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
- ri->rp = NULL;
- hlist_del(&ri->uflist);
- }
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- free_rp_inst(rp);
-}
-
-static int __init init_kprobes(void)
-{
- int i, err = 0;
-
- /* FIXME allocate the probe table, currently defined statically */
- /* initialize all list heads */
- for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
- INIT_HLIST_HEAD(&kprobe_table[i]);
- INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
- }
-
- if (kretprobe_blacklist_size) {
- /* lookup the function address from its name */
- for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
- kprobe_lookup_name(kretprobe_blacklist[i].name,
- kretprobe_blacklist[i].addr);
- if (!kretprobe_blacklist[i].addr)
- printk("kretprobe: lookup failed: %s\n",
- kretprobe_blacklist[i].name);
- }
- }
-
- /* By default, kprobes are enabled */
- kprobe_enabled = true;
-
- err = arch_init_kprobes();
- if (!err)
- err = register_die_notifier(&kprobe_exceptions_nb);
-
- return err;
-}
-
-#ifdef CONFIG_DEBUG_FS
-static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
- const char *sym, int offset,char *modname)
-{
- char *kprobe_type;
-
- if (p->pre_handler == pre_handler_kretprobe)
- kprobe_type = "r";
- else if (p->pre_handler == setjmp_pre_handler)
- kprobe_type = "j";
- else
- kprobe_type = "k";
- if (sym)
- seq_printf(pi, "%p %s %s+0x%x %s\n", p->addr, kprobe_type,
- sym, offset, (modname ? modname : " "));
- else
- seq_printf(pi, "%p %s %p\n", p->addr, kprobe_type, p->addr);
-}
-
-static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
-{
- return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
-}
-
-static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
-{
- (*pos)++;
- if (*pos >= KPROBE_TABLE_SIZE)
- return NULL;
- return pos;
-}
-
-static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
-{
- /* Nothing to do */
-}
-
-static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe *p, *kp;
- const char *sym = NULL;
- unsigned int i = *(loff_t *) v;
- unsigned long offset = 0;
- char *modname, namebuf[128];
-
- head = &kprobe_table[i];
- preempt_disable();
- hlist_for_each_entry_rcu(p, node, head, hlist) {
- sym = kallsyms_lookup((unsigned long)p->addr, NULL,
- &offset, &modname, namebuf);
- if (p->pre_handler == aggr_pre_handler) {
- list_for_each_entry_rcu(kp, &p->list, list)
- report_probe(pi, kp, sym, offset, modname);
- } else
- report_probe(pi, p, sym, offset, modname);
- }
- preempt_enable();
- return 0;
-}
-
-static struct seq_operations kprobes_seq_ops = {
- .start = kprobe_seq_start,
- .next = kprobe_seq_next,
- .stop = kprobe_seq_stop,
- .show = show_kprobe_addr
-};
-
-static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
-{
- return seq_open(filp, &kprobes_seq_ops);
-}
-
-static struct file_operations debugfs_kprobes_operations = {
- .open = kprobes_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
-
-static void __kprobes enable_all_kprobes(void)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe *p;
- unsigned int i;
-
- mutex_lock(&kprobe_mutex);
-
- /* If kprobes are already enabled, just return */
- if (kprobe_enabled)
- goto already_enabled;
-
- for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
- head = &kprobe_table[i];
- hlist_for_each_entry_rcu(p, node, head, hlist)
- arch_arm_kprobe(p);
- }
-
- kprobe_enabled = true;
- printk(KERN_INFO "Kprobes globally enabled\n");
-
-already_enabled:
- mutex_unlock(&kprobe_mutex);
- return;
-}
-
-static void __kprobes disable_all_kprobes(void)
-{
- struct hlist_head *head;
- struct hlist_node *node;
- struct kprobe *p;
- unsigned int i;
-
- mutex_lock(&kprobe_mutex);
-
- /* If kprobes are already disabled, just return */
- if (!kprobe_enabled)
- goto already_disabled;
-
- kprobe_enabled = false;
- printk(KERN_INFO "Kprobes globally disabled\n");
- for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
- head = &kprobe_table[i];
- hlist_for_each_entry_rcu(p, node, head, hlist) {
- if (!arch_trampoline_kprobe(p))
- arch_disarm_kprobe(p);
- }
- }
-
- mutex_unlock(&kprobe_mutex);
- /* Allow all currently running kprobes to complete */
- synchronize_sched();
- return;
-
-already_disabled:
- mutex_unlock(&kprobe_mutex);
- return;
-}
-
-/*
- * XXX: The debugfs bool file interface doesn't allow for callbacks
- * when the bool state is switched. We can reuse that facility when
- * available
- */
-static ssize_t read_enabled_file_bool(struct file *file,
- char __user *user_buf, size_t count, loff_t *ppos)
-{
- char buf[3];
-
- if (kprobe_enabled)
- buf[0] = '1';
- else
- buf[0] = '0';
- buf[1] = '\n';
- buf[2] = 0x00;
- return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
-}
-
-static ssize_t write_enabled_file_bool(struct file *file,
- const char __user *user_buf, size_t count, loff_t *ppos)
-{
- char buf[32];
- int buf_size;
-
- buf_size = min(count, (sizeof(buf)-1));
- if (copy_from_user(buf, user_buf, buf_size))
- return -EFAULT;
-
- switch (buf[0]) {
- case 'y':
- case 'Y':
- case '1':
- enable_all_kprobes();
- break;
- case 'n':
- case 'N':
- case '0':
- disable_all_kprobes();
- break;
- }
-
- return count;
-}
-
-static struct file_operations fops_kp = {
- .read = read_enabled_file_bool,
- .write = write_enabled_file_bool,
-};
-
-static int __kprobes debugfs_kprobe_init(void)
-{
- struct dentry *dir, *file;
- unsigned int value = 1;
-
- dir = debugfs_create_dir("kprobes", NULL);
- if (!dir)
- return -ENOMEM;
-
- file = debugfs_create_file("list", 0444, dir, NULL,
- &debugfs_kprobes_operations);
- if (!file) {
- debugfs_remove(dir);
- return -ENOMEM;
- }
-
- file = debugfs_create_file("enabled", 0600, dir,
- &value, &fops_kp);
- if (!file) {
- debugfs_remove(dir);
- return -ENOMEM;
- }
-
- return 0;
-}
-
-late_initcall(debugfs_kprobe_init);
-#endif /* CONFIG_DEBUG_FS */
-
-module_init(init_kprobes);
-
-EXPORT_SYMBOL_GPL(register_kprobe);
-EXPORT_SYMBOL_GPL(unregister_kprobe);
-EXPORT_SYMBOL_GPL(register_jprobe);
-EXPORT_SYMBOL_GPL(unregister_jprobe);
-#ifdef CONFIG_KPROBES
-EXPORT_SYMBOL_GPL(jprobe_return);
-#endif
-
-#ifdef CONFIG_KPROBES
-EXPORT_SYMBOL_GPL(register_kretprobe);
-EXPORT_SYMBOL_GPL(unregister_kretprobe);
-#endif
Index: linux-2.6-lttng.stable/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/instrumentation/Makefile 2007-10-29 09:51:12.000000000 -0400
+++ linux-2.6-lttng.stable/instrumentation/Makefile 2007-10-29 09:51:46.000000000 -0400
@@ -1,3 +1,5 @@
#
# Makefile for the linux kernel instrumentation
#
+
+obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/kernel/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/Makefile 2007-10-29 09:51:06.000000000 -0400
+++ linux-2.6-lttng.stable/kernel/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -47,7 +47,6 @@ obj-$(CONFIG_STOP_MACHINE) += stop_machi
obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
-obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_SYSFS) += ksysfs.o
obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
Index: linux-2.6-lttng.stable/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/Makefile 2007-10-29 09:51:22.000000000 -0400
+++ linux-2.6-lttng.stable/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -574,7 +574,8 @@ export mod_strip_cmd


ifeq ($(KBUILD_EXTMOD),)
-core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
+core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ \
+ instrumentation/

vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
$(core-y) $(core-m) $(drivers-y) $(drivers-m) \
Index: linux-2.6-lttng.stable/arch/avr32/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/avr32/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,268 @@
+/*
+ * Kernel Probes (KProbes)
+ *
+ * Copyright (C) 2005-2006 Atmel Corporation
+ *
+ * Based on arch/ppc64/kernel/kprobes.c
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+
+#include <asm/cacheflush.h>
+#include <linux/kdebug.h>
+#include <asm/ocd.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe);
+static unsigned long kprobe_status;
+static struct pt_regs jprobe_saved_regs;
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ int ret = 0;
+
+ if ((unsigned long)p->addr & 0x01) {
+ printk("Attempt to register kprobe at an unaligned address\n");
+ ret = -EINVAL;
+ }
+
+ /* XXX: Might be a good idea to check if p->addr is a valid
+ * kernel address as well... */
+
+ if (!ret) {
+ pr_debug("copy kprobe at %p\n", p->addr);
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ p->opcode = *p->addr;
+ }
+
+ return ret;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ pr_debug("arming kprobe at %p\n", p->addr);
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flush_icache_range((unsigned long)p->addr,
+ (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ pr_debug("disarming kprobe at %p\n", p->addr);
+ *p->addr = p->opcode;
+ flush_icache_range((unsigned long)p->addr,
+ (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long dc;
+
+ pr_debug("preparing to singlestep over %p (PC=%08lx)\n",
+ p->addr, regs->pc);
+
+ BUG_ON(!(sysreg_read(SR) & SYSREG_BIT(SR_D)));
+
+ dc = __mfdr(DBGREG_DC);
+ dc |= DC_SS;
+ __mtdr(DBGREG_DC, dc);
+
+ /*
+ * We must run the instruction from its original location
+ * since it may actually reference PC.
+ *
+ * TODO: Do the instruction replacement directly in icache.
+ */
+ *p->addr = p->opcode;
+ flush_icache_range((unsigned long)p->addr,
+ (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long dc;
+
+ pr_debug("resuming execution at PC=%08lx\n", regs->pc);
+
+ dc = __mfdr(DBGREG_DC);
+ dc &= ~DC_SS;
+ __mtdr(DBGREG_DC, dc);
+
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flush_icache_range((unsigned long)p->addr,
+ (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p)
+{
+ __get_cpu_var(current_kprobe) = p;
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ void *addr = (void *)regs->pc;
+ int ret = 0;
+
+ pr_debug("kprobe_handler: kprobe_running=%p\n",
+ kprobe_running());
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+
+ /* Check that we're not recursing */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kprobe_status == KPROBE_HIT_SS) {
+ printk("FIXME: kprobe hit while single-stepping!\n");
+ goto no_kprobe;
+ }
+
+ printk("FIXME: kprobe hit while handling another kprobe\n");
+ goto no_kprobe;
+ } else {
+ p = kprobe_running();
+ if (p->break_handler && p->break_handler(p, regs))
+ goto ss_probe;
+ }
+ /* If it's not ours, can't be delete race, (we hold lock). */
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p)
+ goto no_kprobe;
+
+ kprobe_status = KPROBE_HIT_ACTIVE;
+ set_current_kprobe(p);
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /* handler has already set things up, so skip ss setup */
+ return 1;
+
+ss_probe:
+ prepare_singlestep(p, regs);
+ kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+
+ pr_debug("post_kprobe_handler, cur=%p\n", cur);
+
+ if (!cur)
+ return 0;
+
+ if (cur->post_handler) {
+ kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs);
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+
+ pr_debug("kprobe_fault_handler: trapnr=%d\n", trapnr);
+
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ if (kprobe_status & KPROBE_HIT_SS) {
+ resume_execution(cur, regs);
+ preempt_enable_no_resched();
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ pr_debug("kprobe_exceptions_notify: val=%lu, data=%p\n",
+ val, data);
+
+ switch (val) {
+ case DIE_BREAKPOINT:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_SSTEP:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+
+ memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
+
+ /*
+ * TODO: We should probably save some of the stack here as
+ * well, since gcc may pass arguments on the stack for certain
+ * functions (lots of arguments, large aggregates, varargs)
+ */
+
+ /* setup return addr to the jprobe handler routine */
+ regs->pc = (unsigned long)jp->entry;
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ asm volatile("breakpoint" ::: "memory");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ /*
+ * FIXME - we should ideally be validating that we got here 'cos
+ * of the "trap" in jprobe_return() above, before restoring the
+ * saved regs...
+ */
+ memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
+ return 1;
+}
+
+int __init arch_init_kprobes(void)
+{
+ printk("KPROBES: Enabling monitor mode (MM|DBE)...\n");
+ __mtdr(DBGREG_DC, DC_MM | DC_DBE);
+
+ /* TODO: Register kretprobe trampoline */
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/avr32/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/avr32/kernel/kprobes.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,268 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- *
- * Copyright (C) 2005-2006 Atmel Corporation
- *
- * Based on arch/ppc64/kernel/kprobes.c
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-
-#include <asm/cacheflush.h>
-#include <linux/kdebug.h>
-#include <asm/ocd.h>
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe);
-static unsigned long kprobe_status;
-static struct pt_regs jprobe_saved_regs;
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- int ret = 0;
-
- if ((unsigned long)p->addr & 0x01) {
- printk("Attempt to register kprobe at an unaligned address\n");
- ret = -EINVAL;
- }
-
- /* XXX: Might be a good idea to check if p->addr is a valid
- * kernel address as well... */
-
- if (!ret) {
- pr_debug("copy kprobe at %p\n", p->addr);
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
- p->opcode = *p->addr;
- }
-
- return ret;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- pr_debug("arming kprobe at %p\n", p->addr);
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long)p->addr,
- (unsigned long)p->addr + sizeof(kprobe_opcode_t));
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- pr_debug("disarming kprobe at %p\n", p->addr);
- *p->addr = p->opcode;
- flush_icache_range((unsigned long)p->addr,
- (unsigned long)p->addr + sizeof(kprobe_opcode_t));
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- unsigned long dc;
-
- pr_debug("preparing to singlestep over %p (PC=%08lx)\n",
- p->addr, regs->pc);
-
- BUG_ON(!(sysreg_read(SR) & SYSREG_BIT(SR_D)));
-
- dc = __mfdr(DBGREG_DC);
- dc |= DC_SS;
- __mtdr(DBGREG_DC, dc);
-
- /*
- * We must run the instruction from its original location
- * since it may actually reference PC.
- *
- * TODO: Do the instruction replacement directly in icache.
- */
- *p->addr = p->opcode;
- flush_icache_range((unsigned long)p->addr,
- (unsigned long)p->addr + sizeof(kprobe_opcode_t));
-}
-
-static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
-{
- unsigned long dc;
-
- pr_debug("resuming execution at PC=%08lx\n", regs->pc);
-
- dc = __mfdr(DBGREG_DC);
- dc &= ~DC_SS;
- __mtdr(DBGREG_DC, dc);
-
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long)p->addr,
- (unsigned long)p->addr + sizeof(kprobe_opcode_t));
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p)
-{
- __get_cpu_var(current_kprobe) = p;
-}
-
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- void *addr = (void *)regs->pc;
- int ret = 0;
-
- pr_debug("kprobe_handler: kprobe_running=%p\n",
- kprobe_running());
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
-
- /* Check that we're not recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kprobe_status == KPROBE_HIT_SS) {
- printk("FIXME: kprobe hit while single-stepping!\n");
- goto no_kprobe;
- }
-
- printk("FIXME: kprobe hit while handling another kprobe\n");
- goto no_kprobe;
- } else {
- p = kprobe_running();
- if (p->break_handler && p->break_handler(p, regs))
- goto ss_probe;
- }
- /* If it's not ours, can't be delete race, (we hold lock). */
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p)
- goto no_kprobe;
-
- kprobe_status = KPROBE_HIT_ACTIVE;
- set_current_kprobe(p);
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
- prepare_singlestep(p, regs);
- kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
-
- pr_debug("post_kprobe_handler, cur=%p\n", cur);
-
- if (!cur)
- return 0;
-
- if (cur->post_handler) {
- kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs);
- reset_current_kprobe();
- preempt_enable_no_resched();
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
-
- pr_debug("kprobe_fault_handler: trapnr=%d\n", trapnr);
-
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- if (kprobe_status & KPROBE_HIT_SS) {
- resume_execution(cur, regs);
- preempt_enable_no_resched();
- }
- return 0;
-}
-
-/*
- * Wrapper routine to for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- pr_debug("kprobe_exceptions_notify: val=%lu, data=%p\n",
- val, data);
-
- switch (val) {
- case DIE_BREAKPOINT:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_SSTEP:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- default:
- break;
- }
-
- return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
-
- memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
-
- /*
- * TODO: We should probably save some of the stack here as
- * well, since gcc may pass arguments on the stack for certain
- * functions (lots of arguments, large aggregates, varargs)
- */
-
- /* setup return addr to the jprobe handler routine */
- regs->pc = (unsigned long)jp->entry;
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- asm volatile("breakpoint" ::: "memory");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- /*
- * FIXME - we should ideally be validating that we got here 'cos
- * of the "trap" in jprobe_return() above, before restoring the
- * saved regs...
- */
- memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
- return 1;
-}
-
-int __init arch_init_kprobes(void)
-{
- printk("KPROBES: Enabling monitor mode (MM|DBE)...\n");
- __mtdr(DBGREG_DC, DC_MM | DC_DBE);
-
- /* TODO: Register kretprobe trampoline */
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/ia64/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/ia64/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,1027 @@
+/*
+ * Kernel Probes (KProbes)
+ * arch/ia64/kernel/kprobes.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ * Copyright (C) Intel Corporation, 2005
+ *
+ * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
+ * <anil.s.keshavamurthy@intel.com> adapted from i386
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/moduleloader.h>
+#include <linux/kdebug.h>
+
+#include <asm/pgtable.h>
+#include <asm/sections.h>
+#include <asm/uaccess.h>
+
+extern void jprobe_inst_return(void);
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+enum instruction_type {A, I, M, F, B, L, X, u};
+static enum instruction_type bundle_encoding[32][3] = {
+ { M, I, I }, /* 00 */
+ { M, I, I }, /* 01 */
+ { M, I, I }, /* 02 */
+ { M, I, I }, /* 03 */
+ { M, L, X }, /* 04 */
+ { M, L, X }, /* 05 */
+ { u, u, u }, /* 06 */
+ { u, u, u }, /* 07 */
+ { M, M, I }, /* 08 */
+ { M, M, I }, /* 09 */
+ { M, M, I }, /* 0A */
+ { M, M, I }, /* 0B */
+ { M, F, I }, /* 0C */
+ { M, F, I }, /* 0D */
+ { M, M, F }, /* 0E */
+ { M, M, F }, /* 0F */
+ { M, I, B }, /* 10 */
+ { M, I, B }, /* 11 */
+ { M, B, B }, /* 12 */
+ { M, B, B }, /* 13 */
+ { u, u, u }, /* 14 */
+ { u, u, u }, /* 15 */
+ { B, B, B }, /* 16 */
+ { B, B, B }, /* 17 */
+ { M, M, B }, /* 18 */
+ { M, M, B }, /* 19 */
+ { u, u, u }, /* 1A */
+ { u, u, u }, /* 1B */
+ { M, F, B }, /* 1C */
+ { M, F, B }, /* 1D */
+ { u, u, u }, /* 1E */
+ { u, u, u }, /* 1F */
+};
+
+/*
+ * In this function we check to see if the instruction
+ * is IP relative instruction and update the kprobe
+ * inst flag accordingly
+ */
+static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
+ uint major_opcode,
+ unsigned long kprobe_inst,
+ struct kprobe *p)
+{
+ p->ainsn.inst_flag = 0;
+ p->ainsn.target_br_reg = 0;
+ p->ainsn.slot = slot;
+
+ /* Check for Break instruction
+ * Bits 37:40 Major opcode to be zero
+ * Bits 27:32 X6 to be zero
+ * Bits 32:35 X3 to be zero
+ */
+ if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
+ /* is a break instruction */
+ p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
+ return;
+ }
+
+ if (bundle_encoding[template][slot] == B) {
+ switch (major_opcode) {
+ case INDIRECT_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ case IP_RELATIVE_PREDICT_OPCODE:
+ case IP_RELATIVE_BRANCH_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+ break;
+ case IP_RELATIVE_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ }
+ } else if (bundle_encoding[template][slot] == X) {
+ switch (major_opcode) {
+ case LONG_CALL_OPCODE:
+ p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+ p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+ break;
+ }
+ }
+ return;
+}
+
+/*
+ * In this function we check to see if the instruction
+ * (qp) cmpx.crel.ctype p1,p2=r2,r3
+ * on which we are inserting kprobe is cmp instruction
+ * with ctype as unc.
+ */
+static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
+ uint major_opcode,
+ unsigned long kprobe_inst)
+{
+ cmp_inst_t cmp_inst;
+ uint ctype_unc = 0;
+
+ if (!((bundle_encoding[template][slot] == I) ||
+ (bundle_encoding[template][slot] == M)))
+ goto out;
+
+ if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
+ (major_opcode == 0xE)))
+ goto out;
+
+ cmp_inst.l = kprobe_inst;
+ if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
+ /* Integer compare - Register Register (A6 type)*/
+ if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
+ &&(cmp_inst.f.c == 1))
+ ctype_unc = 1;
+ } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
+ /* Integer compare - Immediate Register (A8 type)*/
+ if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
+ ctype_unc = 1;
+ }
+out:
+ return ctype_unc;
+}
+
+/*
+ * In this function we check to see if the instruction
+ * on which we are inserting kprobe is supported.
+ * Returns qp value if supported
+ * Returns -EINVAL if unsupported
+ */
+static int __kprobes unsupported_inst(uint template, uint slot,
+ uint major_opcode,
+ unsigned long kprobe_inst,
+ unsigned long addr)
+{
+ int qp;
+
+ qp = kprobe_inst & 0x3f;
+ if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
+ if (slot == 1 && qp) {
+ printk(KERN_WARNING "Kprobes on cmp unc"
+ "instruction on slot 1 at <0x%lx>"
+ "is not supported\n", addr);
+ return -EINVAL;
+
+ }
+ qp = 0;
+ }
+ else if (bundle_encoding[template][slot] == I) {
+ if (major_opcode == 0) {
+ /*
+ * Check for Integer speculation instruction
+ * - Bit 33-35 to be equal to 0x1
+ */
+ if (((kprobe_inst >> 33) & 0x7) == 1) {
+ printk(KERN_WARNING
+ "Kprobes on speculation inst at <0x%lx> not supported\n",
+ addr);
+ return -EINVAL;
+ }
+ /*
+ * IP relative mov instruction
+ * - Bit 27-35 to be equal to 0x30
+ */
+ if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
+ printk(KERN_WARNING
+ "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
+ addr);
+ return -EINVAL;
+
+ }
+ }
+ else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
+ (kprobe_inst & (0x1UL << 12))) {
+ /* test bit instructions, tbit,tnat,tf
+ * bit 33-36 to be equal to 0
+ * bit 12 to be equal to 1
+ */
+ if (slot == 1 && qp) {
+ printk(KERN_WARNING "Kprobes on test bit"
+ "instruction on slot at <0x%lx>"
+ "is not supported\n", addr);
+ return -EINVAL;
+ }
+ qp = 0;
+ }
+ }
+ else if (bundle_encoding[template][slot] == B) {
+ if (major_opcode == 7) {
+ /* IP-Relative Predict major code is 7 */
+ printk(KERN_WARNING "Kprobes on IP-Relative"
+ "Predict is not supported\n");
+ return -EINVAL;
+ }
+ else if (major_opcode == 2) {
+ /* Indirect Predict, major code is 2
+ * bit 27-32 to be equal to 10 or 11
+ */
+ int x6=(kprobe_inst >> 27) & 0x3F;
+ if ((x6 == 0x10) || (x6 == 0x11)) {
+ printk(KERN_WARNING "Kprobes on"
+ "Indirect Predict is not supported\n");
+ return -EINVAL;
+ }
+ }
+ }
+ /* kernel does not use float instruction, here for safety kprobe
+ * will judge whether it is fcmp/flass/float approximation instruction
+ */
+ else if (unlikely(bundle_encoding[template][slot] == F)) {
+ if ((major_opcode == 4 || major_opcode == 5) &&
+ (kprobe_inst & (0x1 << 12))) {
+ /* fcmp/fclass unc instruction */
+ if (slot == 1 && qp) {
+ printk(KERN_WARNING "Kprobes on fcmp/fclass "
+ "instruction on slot at <0x%lx> "
+ "is not supported\n", addr);
+ return -EINVAL;
+
+ }
+ qp = 0;
+ }
+ if ((major_opcode == 0 || major_opcode == 1) &&
+ (kprobe_inst & (0x1UL << 33))) {
+ /* float Approximation instruction */
+ if (slot == 1 && qp) {
+ printk(KERN_WARNING "Kprobes on float Approx "
+ "instr at <0x%lx> is not supported\n",
+ addr);
+ return -EINVAL;
+ }
+ qp = 0;
+ }
+ }
+ return qp;
+}
+
+/*
+ * In this function we override the bundle with
+ * the break instruction at the given slot.
+ */
+static void __kprobes prepare_break_inst(uint template, uint slot,
+ uint major_opcode,
+ unsigned long kprobe_inst,
+ struct kprobe *p,
+ int qp)
+{
+ unsigned long break_inst = BREAK_INST;
+ bundle_t *bundle = &p->opcode.bundle;
+
+ /*
+ * Copy the original kprobe_inst qualifying predicate(qp)
+ * to the break instruction
+ */
+ break_inst |= qp;
+
+ switch (slot) {
+ case 0:
+ bundle->quad0.slot0 = break_inst;
+ break;
+ case 1:
+ bundle->quad0.slot1_p0 = break_inst;
+ bundle->quad1.slot1_p1 = break_inst >> (64-46);
+ break;
+ case 2:
+ bundle->quad1.slot2 = break_inst;
+ break;
+ }
+
+ /*
+ * Update the instruction flag, so that we can
+ * emulate the instruction properly after we
+ * single step on original instruction
+ */
+ update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
+}
+
+static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
+ unsigned long *kprobe_inst, uint *major_opcode)
+{
+ unsigned long kprobe_inst_p0, kprobe_inst_p1;
+ unsigned int template;
+
+ template = bundle->quad0.template;
+
+ switch (slot) {
+ case 0:
+ *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
+ *kprobe_inst = bundle->quad0.slot0;
+ break;
+ case 1:
+ *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
+ kprobe_inst_p0 = bundle->quad0.slot1_p0;
+ kprobe_inst_p1 = bundle->quad1.slot1_p1;
+ *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
+ break;
+ case 2:
+ *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
+ *kprobe_inst = bundle->quad1.slot2;
+ break;
+ }
+}
+
+/* Returns non-zero if the addr is in the Interrupt Vector Table */
+static int __kprobes in_ivt_functions(unsigned long addr)
+{
+ return (addr >= (unsigned long)__start_ivt_text
+ && addr < (unsigned long)__end_ivt_text);
+}
+
+static int __kprobes valid_kprobe_addr(int template, int slot,
+ unsigned long addr)
+{
+ if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
+ printk(KERN_WARNING "Attempting to insert unaligned kprobe "
+ "at 0x%lx\n", addr);
+ return -EINVAL;
+ }
+
+ if (in_ivt_functions(addr)) {
+ printk(KERN_WARNING "Kprobes can't be inserted inside "
+ "IVT functions at 0x%lx\n", addr);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ unsigned int i;
+ i = atomic_add_return(1, &kcb->prev_kprobe_index);
+ kcb->prev_kprobe[i-1].kp = kprobe_running();
+ kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ unsigned int i;
+ i = atomic_sub_return(1, &kcb->prev_kprobe_index);
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i].kp;
+ kcb->kprobe_status = kcb->prev_kprobe[i].status;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+}
+
+static void kretprobe_trampoline(void)
+{
+}
+
+/*
+ * At this point the target function has been tricked into
+ * returning into our trampoline. Lookup the associated instance
+ * and then:
+ * - call the handler function
+ * - cleanup by marking the instance as unused
+ * - long jump back to the original return address
+ */
+int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address =
+ ((struct fnptr *)kretprobe_trampoline)->ip;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(current);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because an multiple functions in the call path
+ * have a return probe installed on them, and/or more then one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+ regs->cr_iip = orig_ret_address;
+
+ reset_current_kprobe();
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ preempt_enable_no_resched();
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
+ */
+ return 1;
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *)regs->b0;
+
+ /* Replace the return addr with trampoline addr */
+ regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
+}
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long) p->addr;
+ unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
+ unsigned long kprobe_inst=0;
+ unsigned int slot = addr & 0xf, template, major_opcode = 0;
+ bundle_t *bundle;
+ int qp;
+
+ bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
+ template = bundle->quad0.template;
+
+ if(valid_kprobe_addr(template, slot, addr))
+ return -EINVAL;
+
+ /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
+ if (slot == 1 && bundle_encoding[template][1] == L)
+ slot++;
+
+ /* Get kprobe_inst and major_opcode from the bundle */
+ get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+
+ qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
+ if (qp < 0)
+ return -EINVAL;
+
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+ memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
+ memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
+
+ prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
+
+ return 0;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ unsigned long arm_addr;
+ bundle_t *src, *dest;
+
+ arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+ dest = &((kprobe_opcode_t *)arm_addr)->bundle;
+ src = &p->opcode.bundle;
+
+ flush_icache_range((unsigned long)p->ainsn.insn,
+ (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
+ switch (p->ainsn.slot) {
+ case 0:
+ dest->quad0.slot0 = src->quad0.slot0;
+ break;
+ case 1:
+ dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+ break;
+ case 2:
+ dest->quad1.slot2 = src->quad1.slot2;
+ break;
+ }
+ flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ unsigned long arm_addr;
+ bundle_t *src, *dest;
+
+ arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+ dest = &((kprobe_opcode_t *)arm_addr)->bundle;
+ /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
+ src = &p->ainsn.insn->bundle;
+ switch (p->ainsn.slot) {
+ case 0:
+ dest->quad0.slot0 = src->quad0.slot0;
+ break;
+ case 1:
+ dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+ break;
+ case 2:
+ dest->quad1.slot2 = src->quad1.slot2;
+ break;
+ }
+ flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, 0);
+ mutex_unlock(&kprobe_mutex);
+}
+/*
+ * We are resuming execution after a single step fault, so the pt_regs
+ * structure reflects the register state after we executed the instruction
+ * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
+ * the ip to point back to the original stack address. To set the IP address
+ * to original stack address, handle the case where we need to fixup the
+ * relative IP address and/or fixup branch register.
+ */
+static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
+ unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
+ unsigned long template;
+ int slot = ((unsigned long)p->addr & 0xf);
+
+ template = p->ainsn.insn->bundle.quad0.template;
+
+ if (slot == 1 && bundle_encoding[template][1] == L)
+ slot = 2;
+
+ if (p->ainsn.inst_flag) {
+
+ if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
+ /* Fix relative IP address */
+ regs->cr_iip = (regs->cr_iip - bundle_addr) +
+ resume_addr;
+ }
+
+ if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
+ /*
+ * Fix target branch register, software convention is
+ * to use either b0 or b6 or b7, so just checking
+ * only those registers
+ */
+ switch (p->ainsn.target_br_reg) {
+ case 0:
+ if ((regs->b0 == bundle_addr) ||
+ (regs->b0 == bundle_addr + 0x10)) {
+ regs->b0 = (regs->b0 - bundle_addr) +
+ resume_addr;
+ }
+ break;
+ case 6:
+ if ((regs->b6 == bundle_addr) ||
+ (regs->b6 == bundle_addr + 0x10)) {
+ regs->b6 = (regs->b6 - bundle_addr) +
+ resume_addr;
+ }
+ break;
+ case 7:
+ if ((regs->b7 == bundle_addr) ||
+ (regs->b7 == bundle_addr + 0x10)) {
+ regs->b7 = (regs->b7 - bundle_addr) +
+ resume_addr;
+ }
+ break;
+ } /* end switch */
+ }
+ goto turn_ss_off;
+ }
+
+ if (slot == 2) {
+ if (regs->cr_iip == bundle_addr + 0x10) {
+ regs->cr_iip = resume_addr + 0x10;
+ }
+ } else {
+ if (regs->cr_iip == bundle_addr) {
+ regs->cr_iip = resume_addr;
+ }
+ }
+
+turn_ss_off:
+ /* Turn off Single Step bit */
+ ia64_psr(regs)->ss = 0;
+}
+
+static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
+ unsigned long slot = (unsigned long)p->addr & 0xf;
+
+ /* single step inline if break instruction */
+ if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
+ regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
+ else
+ regs->cr_iip = bundle_addr & ~0xFULL;
+
+ if (slot > 2)
+ slot = 0;
+
+ ia64_psr(regs)->ri = slot;
+
+ /* turn on single stepping */
+ ia64_psr(regs)->ss = 1;
+}
+
+static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
+{
+ unsigned int slot = ia64_psr(regs)->ri;
+ unsigned int template, major_opcode;
+ unsigned long kprobe_inst;
+ unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
+ bundle_t bundle;
+
+ memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
+ template = bundle.quad0.template;
+
+ /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
+ if (slot == 1 && bundle_encoding[template][1] == L)
+ slot++;
+
+ /* Get Kprobe probe instruction at given slot*/
+ get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
+
+ /* For break instruction,
+ * Bits 37:40 Major opcode to be zero
+ * Bits 27:32 X6 to be zero
+ * Bits 32:35 X3 to be zero
+ */
+ if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
+ /* Not a break instruction */
+ return 0;
+ }
+
+ /* Is a break instruction */
+ return 1;
+}
+
+static int __kprobes pre_kprobes_handler(struct die_args *args)
+{
+ struct kprobe *p;
+ int ret = 0;
+ struct pt_regs *regs = args->regs;
+ kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Handle recursion cases */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
+ (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
+ ia64_psr(regs)->ss = 0;
+ goto no_kprobe;
+ }
+ /* We have reentered the pre_kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_ss(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else if (args->err == __IA64_BREAK_JPROBE) {
+ /*
+ * jprobe instrumented function just completed
+ */
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ goto ss_probe;
+ }
+ } else if (!is_ia64_break_inst(regs)) {
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ ret = 1;
+ goto no_kprobe;
+ } else {
+ /* Not our break */
+ goto no_kprobe;
+ }
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (!is_ia64_break_inst(regs)) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ */
+ ret = 1;
+
+ }
+
+ /* Not one of our break, let kernel handle it */
+ goto no_kprobe;
+ }
+
+ set_current_kprobe(p, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /*
+ * Our pre-handler is specifically requesting that we just
+ * do a return. This is used for both the jprobe pre-handler
+ * and the kretprobe trampoline
+ */
+ return 1;
+
+ss_probe:
+ prepare_ss(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+static int __kprobes post_kprobes_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs);
+
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+
+out:
+ preempt_enable_no_resched();
+ return 1;
+}
+
+int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the instruction pointer points back to
+ * the probe address and allow the page fault handler
+ * to continue as a normal page fault.
+ */
+ regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
+ ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ if (ia64_done_with_exception(regs))
+ return 1;
+
+ /*
+ * Let ia64_do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
+ switch(val) {
+ case DIE_BREAK:
+ /* err is break number from ia64_bad_break() */
+ if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
+ || args->err == __IA64_BREAK_JPROBE
+ || args->err == 0)
+ if (pre_kprobes_handler(args))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_FAULT:
+ /* err is vector number from ia64_fault() */
+ if (args->err == 36)
+ if (post_kprobes_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+struct param_bsp_cfm {
+ unsigned long ip;
+ unsigned long *bsp;
+ unsigned long cfm;
+};
+
+static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
+{
+ unsigned long ip;
+ struct param_bsp_cfm *lp = arg;
+
+ do {
+ unw_get_ip(info, &ip);
+ if (ip == 0)
+ break;
+ if (ip == lp->ip) {
+ unw_get_bsp(info, (unsigned long*)&lp->bsp);
+ unw_get_cfm(info, (unsigned long*)&lp->cfm);
+ return;
+ }
+ } while (unw_unwind(info) >= 0);
+ lp->bsp = NULL;
+ lp->cfm = 0;
+ return;
+}
+
+unsigned long arch_deref_entry_point(void *entry)
+{
+ return ((struct fnptr *)entry)->ip;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ unsigned long addr = arch_deref_entry_point(jp->entry);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ struct param_bsp_cfm pa;
+ int bytes;
+
+ /*
+ * Callee owns the argument space and could overwrite it, eg
+ * tail call optimization. So to be absolutely safe
+ * we save the argument space before transferring the control
+ * to instrumented jprobe function which runs in
+ * the process context
+ */
+ pa.ip = regs->cr_iip;
+ unw_init_running(ia64_get_bsp_cfm, &pa);
+ bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
+ - (char *)pa.bsp;
+ memcpy( kcb->jprobes_saved_stacked_regs,
+ pa.bsp,
+ bytes );
+ kcb->bsp = pa.bsp;
+ kcb->cfm = pa.cfm;
+
+ /* save architectural state */
+ kcb->jprobe_saved_regs = *regs;
+
+ /* after rfi, execute the jprobe instrumented function */
+ regs->cr_iip = addr & ~0xFULL;
+ ia64_psr(regs)->ri = addr & 0xf;
+ regs->r1 = ((struct fnptr *)(jp->entry))->gp;
+
+ /*
+ * fix the return address to our jprobe_inst_return() function
+ * in the jprobes.S file
+ */
+ regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
+
+ return 1;
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ int bytes;
+
+ /* restoring architectural state */
+ *regs = kcb->jprobe_saved_regs;
+
+ /* restoring the original argument space */
+ flush_register_stack();
+ bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
+ - (char *)kcb->bsp;
+ memcpy( kcb->bsp,
+ kcb->jprobes_saved_stacked_regs,
+ bytes );
+ invalidate_stacked_regs();
+
+ preempt_enable_no_resched();
+ return 1;
+}
+
+static struct kprobe trampoline_p = {
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+ trampoline_p.addr =
+ (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
+ return register_kprobe(&trampoline_p);
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ if (p->addr ==
+ (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
+ return 1;
+
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/ia64/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/ia64/kernel/kprobes.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,1027 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- * arch/ia64/kernel/kprobes.c
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- * Copyright (C) Intel Corporation, 2005
- *
- * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
- * <anil.s.keshavamurthy@intel.com> adapted from i386
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/preempt.h>
-#include <linux/moduleloader.h>
-#include <linux/kdebug.h>
-
-#include <asm/pgtable.h>
-#include <asm/sections.h>
-#include <asm/uaccess.h>
-
-extern void jprobe_inst_return(void);
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-
-enum instruction_type {A, I, M, F, B, L, X, u};
-static enum instruction_type bundle_encoding[32][3] = {
- { M, I, I }, /* 00 */
- { M, I, I }, /* 01 */
- { M, I, I }, /* 02 */
- { M, I, I }, /* 03 */
- { M, L, X }, /* 04 */
- { M, L, X }, /* 05 */
- { u, u, u }, /* 06 */
- { u, u, u }, /* 07 */
- { M, M, I }, /* 08 */
- { M, M, I }, /* 09 */
- { M, M, I }, /* 0A */
- { M, M, I }, /* 0B */
- { M, F, I }, /* 0C */
- { M, F, I }, /* 0D */
- { M, M, F }, /* 0E */
- { M, M, F }, /* 0F */
- { M, I, B }, /* 10 */
- { M, I, B }, /* 11 */
- { M, B, B }, /* 12 */
- { M, B, B }, /* 13 */
- { u, u, u }, /* 14 */
- { u, u, u }, /* 15 */
- { B, B, B }, /* 16 */
- { B, B, B }, /* 17 */
- { M, M, B }, /* 18 */
- { M, M, B }, /* 19 */
- { u, u, u }, /* 1A */
- { u, u, u }, /* 1B */
- { M, F, B }, /* 1C */
- { M, F, B }, /* 1D */
- { u, u, u }, /* 1E */
- { u, u, u }, /* 1F */
-};
-
-/*
- * In this function we check to see if the instruction
- * is IP relative instruction and update the kprobe
- * inst flag accordingly
- */
-static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
- uint major_opcode,
- unsigned long kprobe_inst,
- struct kprobe *p)
-{
- p->ainsn.inst_flag = 0;
- p->ainsn.target_br_reg = 0;
- p->ainsn.slot = slot;
-
- /* Check for Break instruction
- * Bits 37:40 Major opcode to be zero
- * Bits 27:32 X6 to be zero
- * Bits 32:35 X3 to be zero
- */
- if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
- /* is a break instruction */
- p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
- return;
- }
-
- if (bundle_encoding[template][slot] == B) {
- switch (major_opcode) {
- case INDIRECT_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- case IP_RELATIVE_PREDICT_OPCODE:
- case IP_RELATIVE_BRANCH_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
- break;
- case IP_RELATIVE_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- }
- } else if (bundle_encoding[template][slot] == X) {
- switch (major_opcode) {
- case LONG_CALL_OPCODE:
- p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
- p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
- break;
- }
- }
- return;
-}
-
-/*
- * In this function we check to see if the instruction
- * (qp) cmpx.crel.ctype p1,p2=r2,r3
- * on which we are inserting kprobe is cmp instruction
- * with ctype as unc.
- */
-static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
- uint major_opcode,
- unsigned long kprobe_inst)
-{
- cmp_inst_t cmp_inst;
- uint ctype_unc = 0;
-
- if (!((bundle_encoding[template][slot] == I) ||
- (bundle_encoding[template][slot] == M)))
- goto out;
-
- if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
- (major_opcode == 0xE)))
- goto out;
-
- cmp_inst.l = kprobe_inst;
- if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
- /* Integer compare - Register Register (A6 type)*/
- if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
- &&(cmp_inst.f.c == 1))
- ctype_unc = 1;
- } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
- /* Integer compare - Immediate Register (A8 type)*/
- if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
- ctype_unc = 1;
- }
-out:
- return ctype_unc;
-}
-
-/*
- * In this function we check to see if the instruction
- * on which we are inserting kprobe is supported.
- * Returns qp value if supported
- * Returns -EINVAL if unsupported
- */
-static int __kprobes unsupported_inst(uint template, uint slot,
- uint major_opcode,
- unsigned long kprobe_inst,
- unsigned long addr)
-{
- int qp;
-
- qp = kprobe_inst & 0x3f;
- if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
- if (slot == 1 && qp) {
- printk(KERN_WARNING "Kprobes on cmp unc"
- "instruction on slot 1 at <0x%lx>"
- "is not supported\n", addr);
- return -EINVAL;
-
- }
- qp = 0;
- }
- else if (bundle_encoding[template][slot] == I) {
- if (major_opcode == 0) {
- /*
- * Check for Integer speculation instruction
- * - Bit 33-35 to be equal to 0x1
- */
- if (((kprobe_inst >> 33) & 0x7) == 1) {
- printk(KERN_WARNING
- "Kprobes on speculation inst at <0x%lx> not supported\n",
- addr);
- return -EINVAL;
- }
- /*
- * IP relative mov instruction
- * - Bit 27-35 to be equal to 0x30
- */
- if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
- printk(KERN_WARNING
- "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
- addr);
- return -EINVAL;
-
- }
- }
- else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
- (kprobe_inst & (0x1UL << 12))) {
- /* test bit instructions, tbit,tnat,tf
- * bit 33-36 to be equal to 0
- * bit 12 to be equal to 1
- */
- if (slot == 1 && qp) {
- printk(KERN_WARNING "Kprobes on test bit"
- "instruction on slot at <0x%lx>"
- "is not supported\n", addr);
- return -EINVAL;
- }
- qp = 0;
- }
- }
- else if (bundle_encoding[template][slot] == B) {
- if (major_opcode == 7) {
- /* IP-Relative Predict major code is 7 */
- printk(KERN_WARNING "Kprobes on IP-Relative"
- "Predict is not supported\n");
- return -EINVAL;
- }
- else if (major_opcode == 2) {
- /* Indirect Predict, major code is 2
- * bit 27-32 to be equal to 10 or 11
- */
- int x6=(kprobe_inst >> 27) & 0x3F;
- if ((x6 == 0x10) || (x6 == 0x11)) {
- printk(KERN_WARNING "Kprobes on"
- "Indirect Predict is not supported\n");
- return -EINVAL;
- }
- }
- }
- /* kernel does not use float instruction, here for safety kprobe
- * will judge whether it is fcmp/flass/float approximation instruction
- */
- else if (unlikely(bundle_encoding[template][slot] == F)) {
- if ((major_opcode == 4 || major_opcode == 5) &&
- (kprobe_inst & (0x1 << 12))) {
- /* fcmp/fclass unc instruction */
- if (slot == 1 && qp) {
- printk(KERN_WARNING "Kprobes on fcmp/fclass "
- "instruction on slot at <0x%lx> "
- "is not supported\n", addr);
- return -EINVAL;
-
- }
- qp = 0;
- }
- if ((major_opcode == 0 || major_opcode == 1) &&
- (kprobe_inst & (0x1UL << 33))) {
- /* float Approximation instruction */
- if (slot == 1 && qp) {
- printk(KERN_WARNING "Kprobes on float Approx "
- "instr at <0x%lx> is not supported\n",
- addr);
- return -EINVAL;
- }
- qp = 0;
- }
- }
- return qp;
-}
-
-/*
- * In this function we override the bundle with
- * the break instruction at the given slot.
- */
-static void __kprobes prepare_break_inst(uint template, uint slot,
- uint major_opcode,
- unsigned long kprobe_inst,
- struct kprobe *p,
- int qp)
-{
- unsigned long break_inst = BREAK_INST;
- bundle_t *bundle = &p->opcode.bundle;
-
- /*
- * Copy the original kprobe_inst qualifying predicate(qp)
- * to the break instruction
- */
- break_inst |= qp;
-
- switch (slot) {
- case 0:
- bundle->quad0.slot0 = break_inst;
- break;
- case 1:
- bundle->quad0.slot1_p0 = break_inst;
- bundle->quad1.slot1_p1 = break_inst >> (64-46);
- break;
- case 2:
- bundle->quad1.slot2 = break_inst;
- break;
- }
-
- /*
- * Update the instruction flag, so that we can
- * emulate the instruction properly after we
- * single step on original instruction
- */
- update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
-}
-
-static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
- unsigned long *kprobe_inst, uint *major_opcode)
-{
- unsigned long kprobe_inst_p0, kprobe_inst_p1;
- unsigned int template;
-
- template = bundle->quad0.template;
-
- switch (slot) {
- case 0:
- *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
- *kprobe_inst = bundle->quad0.slot0;
- break;
- case 1:
- *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
- kprobe_inst_p0 = bundle->quad0.slot1_p0;
- kprobe_inst_p1 = bundle->quad1.slot1_p1;
- *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
- break;
- case 2:
- *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
- *kprobe_inst = bundle->quad1.slot2;
- break;
- }
-}
-
-/* Returns non-zero if the addr is in the Interrupt Vector Table */
-static int __kprobes in_ivt_functions(unsigned long addr)
-{
- return (addr >= (unsigned long)__start_ivt_text
- && addr < (unsigned long)__end_ivt_text);
-}
-
-static int __kprobes valid_kprobe_addr(int template, int slot,
- unsigned long addr)
-{
- if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
- printk(KERN_WARNING "Attempting to insert unaligned kprobe "
- "at 0x%lx\n", addr);
- return -EINVAL;
- }
-
- if (in_ivt_functions(addr)) {
- printk(KERN_WARNING "Kprobes can't be inserted inside "
- "IVT functions at 0x%lx\n", addr);
- return -EINVAL;
- }
-
- return 0;
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- unsigned int i;
- i = atomic_add_return(1, &kcb->prev_kprobe_index);
- kcb->prev_kprobe[i-1].kp = kprobe_running();
- kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- unsigned int i;
- i = atomic_sub_return(1, &kcb->prev_kprobe_index);
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i].kp;
- kcb->kprobe_status = kcb->prev_kprobe[i].status;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
-}
-
-static void kretprobe_trampoline(void)
-{
-}
-
-/*
- * At this point the target function has been tricked into
- * returning into our trampoline. Lookup the associated instance
- * and then:
- * - call the handler function
- * - cleanup by marking the instance as unused
- * - long jump back to the original return address
- */
-int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =
- ((struct fnptr *)kretprobe_trampoline)->ip;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler)
- ri->rp->handler(ri, regs);
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
- regs->cr_iip = orig_ret_address;
-
- reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- preempt_enable_no_resched();
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
- * to run (and have re-enabled preemption)
- */
- return 1;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- ri->ret_addr = (kprobe_opcode_t *)regs->b0;
-
- /* Replace the return addr with trampoline addr */
- regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- unsigned long addr = (unsigned long) p->addr;
- unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
- unsigned long kprobe_inst=0;
- unsigned int slot = addr & 0xf, template, major_opcode = 0;
- bundle_t *bundle;
- int qp;
-
- bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
- template = bundle->quad0.template;
-
- if(valid_kprobe_addr(template, slot, addr))
- return -EINVAL;
-
- /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
- if (slot == 1 && bundle_encoding[template][1] == L)
- slot++;
-
- /* Get kprobe_inst and major_opcode from the bundle */
- get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
-
- qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
- if (qp < 0)
- return -EINVAL;
-
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn)
- return -ENOMEM;
- memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
- memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
-
- prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
-
- return 0;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- unsigned long arm_addr;
- bundle_t *src, *dest;
-
- arm_addr = ((unsigned long)p->addr) & ~0xFUL;
- dest = &((kprobe_opcode_t *)arm_addr)->bundle;
- src = &p->opcode.bundle;
-
- flush_icache_range((unsigned long)p->ainsn.insn,
- (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
- switch (p->ainsn.slot) {
- case 0:
- dest->quad0.slot0 = src->quad0.slot0;
- break;
- case 1:
- dest->quad1.slot1_p1 = src->quad1.slot1_p1;
- break;
- case 2:
- dest->quad1.slot2 = src->quad1.slot2;
- break;
- }
- flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- unsigned long arm_addr;
- bundle_t *src, *dest;
-
- arm_addr = ((unsigned long)p->addr) & ~0xFUL;
- dest = &((kprobe_opcode_t *)arm_addr)->bundle;
- /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
- src = &p->ainsn.insn->bundle;
- switch (p->ainsn.slot) {
- case 0:
- dest->quad0.slot0 = src->quad0.slot0;
- break;
- case 1:
- dest->quad1.slot1_p1 = src->quad1.slot1_p1;
- break;
- case 2:
- dest->quad1.slot2 = src->quad1.slot2;
- break;
- }
- flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
-}
-/*
- * We are resuming execution after a single step fault, so the pt_regs
- * structure reflects the register state after we executed the instruction
- * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
- * the ip to point back to the original stack address. To set the IP address
- * to original stack address, handle the case where we need to fixup the
- * relative IP address and/or fixup branch register.
- */
-static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
-{
- unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
- unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
- unsigned long template;
- int slot = ((unsigned long)p->addr & 0xf);
-
- template = p->ainsn.insn->bundle.quad0.template;
-
- if (slot == 1 && bundle_encoding[template][1] == L)
- slot = 2;
-
- if (p->ainsn.inst_flag) {
-
- if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
- /* Fix relative IP address */
- regs->cr_iip = (regs->cr_iip - bundle_addr) +
- resume_addr;
- }
-
- if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
- /*
- * Fix target branch register, software convention is
- * to use either b0 or b6 or b7, so just checking
- * only those registers
- */
- switch (p->ainsn.target_br_reg) {
- case 0:
- if ((regs->b0 == bundle_addr) ||
- (regs->b0 == bundle_addr + 0x10)) {
- regs->b0 = (regs->b0 - bundle_addr) +
- resume_addr;
- }
- break;
- case 6:
- if ((regs->b6 == bundle_addr) ||
- (regs->b6 == bundle_addr + 0x10)) {
- regs->b6 = (regs->b6 - bundle_addr) +
- resume_addr;
- }
- break;
- case 7:
- if ((regs->b7 == bundle_addr) ||
- (regs->b7 == bundle_addr + 0x10)) {
- regs->b7 = (regs->b7 - bundle_addr) +
- resume_addr;
- }
- break;
- } /* end switch */
- }
- goto turn_ss_off;
- }
-
- if (slot == 2) {
- if (regs->cr_iip == bundle_addr + 0x10) {
- regs->cr_iip = resume_addr + 0x10;
- }
- } else {
- if (regs->cr_iip == bundle_addr) {
- regs->cr_iip = resume_addr;
- }
- }
-
-turn_ss_off:
- /* Turn off Single Step bit */
- ia64_psr(regs)->ss = 0;
-}
-
-static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
-{
- unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
- unsigned long slot = (unsigned long)p->addr & 0xf;
-
- /* single step inline if break instruction */
- if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
- regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
- else
- regs->cr_iip = bundle_addr & ~0xFULL;
-
- if (slot > 2)
- slot = 0;
-
- ia64_psr(regs)->ri = slot;
-
- /* turn on single stepping */
- ia64_psr(regs)->ss = 1;
-}
-
-static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
-{
- unsigned int slot = ia64_psr(regs)->ri;
- unsigned int template, major_opcode;
- unsigned long kprobe_inst;
- unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
- bundle_t bundle;
-
- memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
- template = bundle.quad0.template;
-
- /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
- if (slot == 1 && bundle_encoding[template][1] == L)
- slot++;
-
- /* Get Kprobe probe instruction at given slot*/
- get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
-
- /* For break instruction,
- * Bits 37:40 Major opcode to be zero
- * Bits 27:32 X6 to be zero
- * Bits 32:35 X3 to be zero
- */
- if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
- /* Not a break instruction */
- return 0;
- }
-
- /* Is a break instruction */
- return 1;
-}
-
-static int __kprobes pre_kprobes_handler(struct die_args *args)
-{
- struct kprobe *p;
- int ret = 0;
- struct pt_regs *regs = args->regs;
- kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
- struct kprobe_ctlblk *kcb;
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Handle recursion cases */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
- (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
- ia64_psr(regs)->ss = 0;
- goto no_kprobe;
- }
- /* We have reentered the pre_kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_ss(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- } else if (args->err == __IA64_BREAK_JPROBE) {
- /*
- * jprobe instrumented function just completed
- */
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- } else if (!is_ia64_break_inst(regs)) {
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- ret = 1;
- goto no_kprobe;
- } else {
- /* Not our break */
- goto no_kprobe;
- }
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (!is_ia64_break_inst(regs)) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- */
- ret = 1;
-
- }
-
- /* Not one of our break, let kernel handle it */
- goto no_kprobe;
- }
-
- set_current_kprobe(p, kcb);
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-
- if (p->pre_handler && p->pre_handler(p, regs))
- /*
- * Our pre-handler is specifically requesting that we just
- * do a return. This is used for both the jprobe pre-handler
- * and the kretprobe trampoline
- */
- return 1;
-
-ss_probe:
- prepare_ss(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-static int __kprobes post_kprobes_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs);
-
- /*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-
-out:
- preempt_enable_no_resched();
- return 1;
-}
-
-int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the instruction pointer points back to
- * the probe address and allow the page fault handler
- * to continue as a normal page fault.
- */
- regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
- ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- if (ia64_done_with_exception(regs))
- return 1;
-
- /*
- * Let ia64_do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
-
- return 0;
-}
-
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode(args->regs))
- return ret;
-
- switch(val) {
- case DIE_BREAK:
- /* err is break number from ia64_bad_break() */
- if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
- || args->err == __IA64_BREAK_JPROBE
- || args->err == 0)
- if (pre_kprobes_handler(args))
- ret = NOTIFY_STOP;
- break;
- case DIE_FAULT:
- /* err is vector number from ia64_fault() */
- if (args->err == 36)
- if (post_kprobes_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- default:
- break;
- }
- return ret;
-}
-
-struct param_bsp_cfm {
- unsigned long ip;
- unsigned long *bsp;
- unsigned long cfm;
-};
-
-static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
-{
- unsigned long ip;
- struct param_bsp_cfm *lp = arg;
-
- do {
- unw_get_ip(info, &ip);
- if (ip == 0)
- break;
- if (ip == lp->ip) {
- unw_get_bsp(info, (unsigned long*)&lp->bsp);
- unw_get_cfm(info, (unsigned long*)&lp->cfm);
- return;
- }
- } while (unw_unwind(info) >= 0);
- lp->bsp = NULL;
- lp->cfm = 0;
- return;
-}
-
-unsigned long arch_deref_entry_point(void *entry)
-{
- return ((struct fnptr *)entry)->ip;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr = arch_deref_entry_point(jp->entry);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- struct param_bsp_cfm pa;
- int bytes;
-
- /*
- * Callee owns the argument space and could overwrite it, eg
- * tail call optimization. So to be absolutely safe
- * we save the argument space before transferring the control
- * to instrumented jprobe function which runs in
- * the process context
- */
- pa.ip = regs->cr_iip;
- unw_init_running(ia64_get_bsp_cfm, &pa);
- bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
- - (char *)pa.bsp;
- memcpy( kcb->jprobes_saved_stacked_regs,
- pa.bsp,
- bytes );
- kcb->bsp = pa.bsp;
- kcb->cfm = pa.cfm;
-
- /* save architectural state */
- kcb->jprobe_saved_regs = *regs;
-
- /* after rfi, execute the jprobe instrumented function */
- regs->cr_iip = addr & ~0xFULL;
- ia64_psr(regs)->ri = addr & 0xf;
- regs->r1 = ((struct fnptr *)(jp->entry))->gp;
-
- /*
- * fix the return address to our jprobe_inst_return() function
- * in the jprobes.S file
- */
- regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
-
- return 1;
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- int bytes;
-
- /* restoring architectural state */
- *regs = kcb->jprobe_saved_regs;
-
- /* restoring the original argument space */
- flush_register_stack();
- bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
- - (char *)kcb->bsp;
- memcpy( kcb->bsp,
- kcb->jprobes_saved_stacked_regs,
- bytes );
- invalidate_stacked_regs();
-
- preempt_enable_no_resched();
- return 1;
-}
-
-static struct kprobe trampoline_p = {
- .pre_handler = trampoline_probe_handler
-};
-
-int __init arch_init_kprobes(void)
-{
- trampoline_p.addr =
- (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
- return register_kprobe(&trampoline_p);
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- if (p->addr ==
- (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
- return 1;
-
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/powerpc/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/powerpc/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,559 @@
+/*
+ * Kernel Probes (KProbes)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ * Probes initial implementation ( includes contributions from
+ * Rusty Russell).
+ * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ * interface to access function arguments.
+ * 2004-Nov Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port
+ * for PPC64
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/preempt.h>
+#include <linux/module.h>
+#include <linux/kdebug.h>
+#include <asm/cacheflush.h>
+#include <asm/sstep.h>
+#include <asm/uaccess.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ int ret = 0;
+ kprobe_opcode_t insn = *p->addr;
+
+ if ((unsigned long)p->addr & 0x03) {
+ printk("Attempt to register kprobe at an unaligned address\n");
+ ret = -EINVAL;
+ } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
+ printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
+ ret = -EINVAL;
+ }
+
+ /* insn must be on a special executable page on ppc64 */
+ if (!ret) {
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ ret = -ENOMEM;
+ }
+
+ if (!ret) {
+ memcpy(p->ainsn.insn, p->addr,
+ MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ p->opcode = *p->addr;
+ flush_icache_range((unsigned long)p->ainsn.insn,
+ (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
+ }
+
+ p->ainsn.boostable = 0;
+ return ret;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flush_icache_range((unsigned long) p->addr,
+ (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ *p->addr = p->opcode;
+ flush_icache_range((unsigned long) p->addr,
+ (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, 0);
+ mutex_unlock(&kprobe_mutex);
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ regs->msr |= MSR_SE;
+
+ /*
+ * On powerpc we should single step on the original
+ * instruction even if the probed insn is a trap
+ * variant as values in regs could play a part in
+ * if the trap is taken or not
+ */
+ regs->nip = (unsigned long)p->ainsn.insn;
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_saved_msr = regs->msr;
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *)regs->link;
+
+ /* Replace the return addr with trampoline addr */
+ regs->link = (unsigned long)kretprobe_trampoline;
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ int ret = 0;
+ unsigned int *addr = (unsigned int *)regs->nip;
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Check we're not actually recursing */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ kprobe_opcode_t insn = *p->ainsn.insn;
+ if (kcb->kprobe_status == KPROBE_HIT_SS &&
+ is_trap(insn)) {
+ regs->msr &= ~MSR_SE;
+ regs->msr |= kcb->kprobe_saved_msr;
+ goto no_kprobe;
+ }
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_saved_msr = regs->msr;
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /* If trap variant, then it belongs not to us */
+ kprobe_opcode_t cur_insn = *addr;
+ if (is_trap(cur_insn))
+ goto no_kprobe;
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ ret = 1;
+ goto no_kprobe;
+ }
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ goto ss_probe;
+ }
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * PowerPC has multiple variants of the "trap"
+ * instruction. If the current instruction is a
+ * trap variant, it could belong to someone else
+ */
+ kprobe_opcode_t cur_insn = *addr;
+ if (is_trap(cur_insn))
+ goto no_kprobe;
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ */
+ ret = 1;
+ }
+ /* Not one of ours: let kernel handle it */
+ goto no_kprobe;
+ }
+
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+ set_current_kprobe(p, regs, kcb);
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /* handler has already set things up, so skip ss setup */
+ return 1;
+
+ss_probe:
+ if (p->ainsn.boostable >= 0) {
+ unsigned int insn = *p->ainsn.insn;
+
+ /* regs->nip is also adjusted if emulate_step returns 1 */
+ ret = emulate_step(regs, insn);
+ if (ret > 0) {
+ /*
+ * Once this instruction has been boosted
+ * successfully, set the boostable flag
+ */
+ if (unlikely(p->ainsn.boostable == 0))
+ p->ainsn.boostable = 1;
+
+ if (p->post_handler)
+ p->post_handler(p, regs, 0);
+
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ return 1;
+ } else if (ret < 0) {
+ /*
+ * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
+ * So, we should never get here... but, its still
+ * good to catch them, just in case...
+ */
+ printk("Can't step on instruction %x\n", insn);
+ BUG();
+ } else if (ret == 0)
+ /* This instruction can't be boosted */
+ p->ainsn.boostable = -1;
+ }
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/*
+ * Function return probe trampoline:
+ * - init_kprobes() establishes a probepoint here
+ * - When the probed function returns, this probe
+ * causes the handlers to fire
+ */
+void kretprobe_trampoline_holder(void)
+{
+ asm volatile(".global kretprobe_trampoline\n"
+ "kretprobe_trampoline:\n"
+ "nop\n");
+}
+
+/*
+ * Called when the probe at kretprobe trampoline is hit
+ */
+int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(current);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because an multiple functions in the call path
+ * have a return probe installed on them, and/or more then one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+ regs->nip = orig_ret_address;
+
+ reset_current_kprobe();
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ preempt_enable_no_resched();
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
+ */
+ return 1;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction whose first byte has been replaced by the "breakpoint"
+ * instruction. To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is p->ainsn.insn.
+ */
+static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+ int ret;
+ unsigned int insn = *p->ainsn.insn;
+
+ regs->nip = (unsigned long)p->addr;
+ ret = emulate_step(regs, insn);
+ if (ret == 0)
+ regs->nip = (unsigned long)p->addr + 4;
+}
+
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs);
+ regs->msr |= kcb->kprobe_saved_msr;
+
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ /*
+ * if somebody else is singlestepping across a probe point, msr
+ * will have SE set, in which case, continue the remaining processing
+ * of do_debug, as if this is not a probe hit.
+ */
+ if (regs->msr & MSR_SE)
+ return 0;
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ const struct exception_table_entry *entry;
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the nip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->nip = (unsigned long)cur->addr;
+ regs->msr &= ~MSR_SE;
+ regs->msr |= kcb->kprobe_saved_msr;
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ if ((entry = search_exception_tables(regs->nip)) != NULL) {
+ regs->nip = entry->fixup;
+ return 1;
+ }
+
+ /*
+ * fixup_exception() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
+ switch (val) {
+ case DIE_BPT:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_SSTEP:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+#ifdef CONFIG_PPC64
+unsigned long arch_deref_entry_point(void *entry)
+{
+ return (unsigned long)(((func_descr_t *)entry)->entry);
+}
+#endif
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
+
+ /* setup return addr to the jprobe handler routine */
+ regs->nip = arch_deref_entry_point(jp->entry);
+#ifdef CONFIG_PPC64
+ regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
+#endif
+
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ asm volatile("trap" ::: "memory");
+}
+
+void __kprobes jprobe_return_end(void)
+{
+};
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ /*
+ * FIXME - we should ideally be validating that we got here 'cos
+ * of the "trap" in jprobe_return() above, before restoring the
+ * saved regs...
+ */
+ memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
+ preempt_enable_no_resched();
+ return 1;
+}
+
+static struct kprobe trampoline_p = {
+ .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+ return register_kprobe(&trampoline_p);
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+ return 1;
+
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/powerpc/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/powerpc/kernel/kprobes.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,559 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- * Probes initial implementation ( includes contributions from
- * Rusty Russell).
- * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- * interface to access function arguments.
- * 2004-Nov Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port
- * for PPC64
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/preempt.h>
-#include <linux/module.h>
-#include <linux/kdebug.h>
-#include <asm/cacheflush.h>
-#include <asm/sstep.h>
-#include <asm/uaccess.h>
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- int ret = 0;
- kprobe_opcode_t insn = *p->addr;
-
- if ((unsigned long)p->addr & 0x03) {
- printk("Attempt to register kprobe at an unaligned address\n");
- ret = -EINVAL;
- } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
- printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
- ret = -EINVAL;
- }
-
- /* insn must be on a special executable page on ppc64 */
- if (!ret) {
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn)
- ret = -ENOMEM;
- }
-
- if (!ret) {
- memcpy(p->ainsn.insn, p->addr,
- MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
- p->opcode = *p->addr;
- flush_icache_range((unsigned long)p->ainsn.insn,
- (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
- }
-
- p->ainsn.boostable = 0;
- return ret;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- *p->addr = p->opcode;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- regs->msr |= MSR_SE;
-
- /*
- * On powerpc we should single step on the original
- * instruction even if the probed insn is a trap
- * variant as values in regs could play a part in
- * if the trap is taken or not
- */
- regs->nip = (unsigned long)p->ainsn.insn;
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_msr = regs->msr;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- ri->ret_addr = (kprobe_opcode_t *)regs->link;
-
- /* Replace the return addr with trampoline addr */
- regs->link = (unsigned long)kretprobe_trampoline;
-}
-
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- int ret = 0;
- unsigned int *addr = (unsigned int *)regs->nip;
- struct kprobe_ctlblk *kcb;
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Check we're not actually recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- kprobe_opcode_t insn = *p->ainsn.insn;
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- is_trap(insn)) {
- regs->msr &= ~MSR_SE;
- regs->msr |= kcb->kprobe_saved_msr;
- goto no_kprobe;
- }
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kcb->kprobe_saved_msr = regs->msr;
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /* If trap variant, then it belongs not to us */
- kprobe_opcode_t cur_insn = *addr;
- if (is_trap(cur_insn))
- goto no_kprobe;
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- ret = 1;
- goto no_kprobe;
- }
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * PowerPC has multiple variants of the "trap"
- * instruction. If the current instruction is a
- * trap variant, it could belong to someone else
- */
- kprobe_opcode_t cur_insn = *addr;
- if (is_trap(cur_insn))
- goto no_kprobe;
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- */
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
- goto no_kprobe;
- }
-
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- set_current_kprobe(p, regs, kcb);
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
- if (p->ainsn.boostable >= 0) {
- unsigned int insn = *p->ainsn.insn;
-
- /* regs->nip is also adjusted if emulate_step returns 1 */
- ret = emulate_step(regs, insn);
- if (ret > 0) {
- /*
- * Once this instruction has been boosted
- * successfully, set the boostable flag
- */
- if (unlikely(p->ainsn.boostable == 0))
- p->ainsn.boostable = 1;
-
- if (p->post_handler)
- p->post_handler(p, regs, 0);
-
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- reset_current_kprobe();
- preempt_enable_no_resched();
- return 1;
- } else if (ret < 0) {
- /*
- * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
- * So, we should never get here... but, its still
- * good to catch them, just in case...
- */
- printk("Can't step on instruction %x\n", insn);
- BUG();
- } else if (ret == 0)
- /* This instruction can't be boosted */
- p->ainsn.boostable = -1;
- }
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/*
- * Function return probe trampoline:
- * - init_kprobes() establishes a probepoint here
- * - When the probed function returns, this probe
- * causes the handlers to fire
- */
-void kretprobe_trampoline_holder(void)
-{
- asm volatile(".global kretprobe_trampoline\n"
- "kretprobe_trampoline:\n"
- "nop\n");
-}
-
-/*
- * Called when the probe at kretprobe trampoline is hit
- */
-int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler)
- ri->rp->handler(ri, regs);
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
- regs->nip = orig_ret_address;
-
- reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- preempt_enable_no_resched();
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
- * to run (and have re-enabled preemption)
- */
- return 1;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the "breakpoint"
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is p->ainsn.insn.
- */
-static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
-{
- int ret;
- unsigned int insn = *p->ainsn.insn;
-
- regs->nip = (unsigned long)p->addr;
- ret = emulate_step(regs, insn);
- if (ret == 0)
- regs->nip = (unsigned long)p->addr + 4;
-}
-
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs);
- regs->msr |= kcb->kprobe_saved_msr;
-
- /*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- /*
- * if somebody else is singlestepping across a probe point, msr
- * will have SE set, in which case, continue the remaining processing
- * of do_debug, as if this is not a probe hit.
- */
- if (regs->msr & MSR_SE)
- return 0;
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- const struct exception_table_entry *entry;
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the nip points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->nip = (unsigned long)cur->addr;
- regs->msr &= ~MSR_SE;
- regs->msr |= kcb->kprobe_saved_msr;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- if ((entry = search_exception_tables(regs->nip)) != NULL) {
- regs->nip = entry->fixup;
- return 1;
- }
-
- /*
- * fixup_exception() could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
- return 0;
-}
-
-/*
- * Wrapper routine to for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode(args->regs))
- return ret;
-
- switch (val) {
- case DIE_BPT:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_SSTEP:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- default:
- break;
- }
- return ret;
-}
-
-#ifdef CONFIG_PPC64
-unsigned long arch_deref_entry_point(void *entry)
-{
- return (unsigned long)(((func_descr_t *)entry)->entry);
-}
-#endif
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
-
- /* setup return addr to the jprobe handler routine */
- regs->nip = arch_deref_entry_point(jp->entry);
-#ifdef CONFIG_PPC64
- regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
-#endif
-
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- asm volatile("trap" ::: "memory");
-}
-
-void __kprobes jprobe_return_end(void)
-{
-};
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- /*
- * FIXME - we should ideally be validating that we got here 'cos
- * of the "trap" in jprobe_return() above, before restoring the
- * saved regs...
- */
- memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
- preempt_enable_no_resched();
- return 1;
-}
-
-static struct kprobe trampoline_p = {
- .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
- .pre_handler = trampoline_probe_handler
-};
-
-int __init arch_init_kprobes(void)
-{
- return register_kprobe(&trampoline_p);
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
- return 1;
-
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/s390/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/s390/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,672 @@
+/*
+ * Kernel Probes (KProbes)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2006
+ *
+ * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/preempt.h>
+#include <linux/stop_machine.h>
+#include <linux/kdebug.h>
+#include <asm/cacheflush.h>
+#include <asm/sections.h>
+#include <asm/uaccess.h>
+#include <linux/module.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ /* Make sure the probe isn't going on a difficult instruction */
+ if (is_prohibited_opcode((kprobe_opcode_t *) p->addr))
+ return -EINVAL;
+
+ if ((unsigned long)p->addr & 0x01) {
+ printk("Attempt to register kprobe at an unaligned address\n");
+ return -EINVAL;
+ }
+
+ /* Use the get_insn_slot() facility for correctness */
+ if (!(p->ainsn.insn = get_insn_slot()))
+ return -ENOMEM;
+
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+
+ get_instruction_type(&p->ainsn);
+ p->opcode = *p->addr;
+ return 0;
+}
+
+int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction)
+{
+ switch (*(__u8 *) instruction) {
+ case 0x0c: /* bassm */
+ case 0x0b: /* bsm */
+ case 0x83: /* diag */
+ case 0x44: /* ex */
+ return -EINVAL;
+ }
+ switch (*(__u16 *) instruction) {
+ case 0x0101: /* pr */
+ case 0xb25a: /* bsa */
+ case 0xb240: /* bakr */
+ case 0xb258: /* bsg */
+ case 0xb218: /* pc */
+ case 0xb228: /* pt */
+ return -EINVAL;
+ }
+ return 0;
+}
+
+void __kprobes get_instruction_type(struct arch_specific_insn *ainsn)
+{
+ /* default fixup method */
+ ainsn->fixup = FIXUP_PSW_NORMAL;
+
+ /* save r1 operand */
+ ainsn->reg = (*ainsn->insn & 0xf0) >> 4;
+
+ /* save the instruction length (pop 5-5) in bytes */
+ switch (*(__u8 *) (ainsn->insn) >> 6) {
+ case 0:
+ ainsn->ilen = 2;
+ break;
+ case 1:
+ case 2:
+ ainsn->ilen = 4;
+ break;
+ case 3:
+ ainsn->ilen = 6;
+ break;
+ }
+
+ switch (*(__u8 *) ainsn->insn) {
+ case 0x05: /* balr */
+ case 0x0d: /* basr */
+ ainsn->fixup = FIXUP_RETURN_REGISTER;
+ /* if r2 = 0, no branch will be taken */
+ if ((*ainsn->insn & 0x0f) == 0)
+ ainsn->fixup |= FIXUP_BRANCH_NOT_TAKEN;
+ break;
+ case 0x06: /* bctr */
+ case 0x07: /* bcr */
+ ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
+ break;
+ case 0x45: /* bal */
+ case 0x4d: /* bas */
+ ainsn->fixup = FIXUP_RETURN_REGISTER;
+ break;
+ case 0x47: /* bc */
+ case 0x46: /* bct */
+ case 0x86: /* bxh */
+ case 0x87: /* bxle */
+ ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
+ break;
+ case 0x82: /* lpsw */
+ ainsn->fixup = FIXUP_NOT_REQUIRED;
+ break;
+ case 0xb2: /* lpswe */
+ if (*(((__u8 *) ainsn->insn) + 1) == 0xb2) {
+ ainsn->fixup = FIXUP_NOT_REQUIRED;
+ }
+ break;
+ case 0xa7: /* bras */
+ if ((*ainsn->insn & 0x0f) == 0x05) {
+ ainsn->fixup |= FIXUP_RETURN_REGISTER;
+ }
+ break;
+ case 0xc0:
+ if ((*ainsn->insn & 0x0f) == 0x00 /* larl */
+ || (*ainsn->insn & 0x0f) == 0x05) /* brasl */
+ ainsn->fixup |= FIXUP_RETURN_REGISTER;
+ break;
+ case 0xeb:
+ if (*(((__u8 *) ainsn->insn) + 5 ) == 0x44 || /* bxhg */
+ *(((__u8 *) ainsn->insn) + 5) == 0x45) {/* bxleg */
+ ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
+ }
+ break;
+ case 0xe3: /* bctg */
+ if (*(((__u8 *) ainsn->insn) + 5) == 0x46) {
+ ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
+ }
+ break;
+ }
+}
+
+static int __kprobes swap_instruction(void *aref)
+{
+ struct ins_replace_args *args = aref;
+ u32 *addr;
+ u32 instr;
+ int err = -EFAULT;
+
+ /*
+ * Text segment is read-only, hence we use stura to bypass dynamic
+ * address translation to exchange the instruction. Since stura
+ * always operates on four bytes, but we only want to exchange two
+ * bytes do some calculations to get things right. In addition we
+ * shall not cross any page boundaries (vmalloc area!) when writing
+ * the new instruction.
+ */
+ addr = (u32 *)((unsigned long)args->ptr & -4UL);
+ if ((unsigned long)args->ptr & 2)
+ instr = ((*addr) & 0xffff0000) | args->new;
+ else
+ instr = ((*addr) & 0x0000ffff) | args->new << 16;
+
+ asm volatile(
+ " lra %1,0(%1)\n"
+ "0: stura %2,%1\n"
+ "1: la %0,0\n"
+ "2:\n"
+ EX_TABLE(0b,2b)
+ : "+d" (err)
+ : "a" (addr), "d" (instr)
+ : "memory", "cc");
+
+ return err;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ unsigned long status = kcb->kprobe_status;
+ struct ins_replace_args args;
+
+ args.ptr = p->addr;
+ args.old = p->opcode;
+ args.new = BREAKPOINT_INSTRUCTION;
+
+ kcb->kprobe_status = KPROBE_SWAP_INST;
+ stop_machine_run(swap_instruction, &args, NR_CPUS);
+ kcb->kprobe_status = status;
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ unsigned long status = kcb->kprobe_status;
+ struct ins_replace_args args;
+
+ args.ptr = p->addr;
+ args.old = BREAKPOINT_INSTRUCTION;
+ args.new = p->opcode;
+
+ kcb->kprobe_status = KPROBE_SWAP_INST;
+ stop_machine_run(swap_instruction, &args, NR_CPUS);
+ kcb->kprobe_status = status;
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, 0);
+ mutex_unlock(&kprobe_mutex);
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ per_cr_bits kprobe_per_regs[1];
+
+ memset(kprobe_per_regs, 0, sizeof(per_cr_bits));
+ regs->psw.addr = (unsigned long)p->ainsn.insn | PSW_ADDR_AMODE;
+
+ /* Set up the per control reg info, will pass to lctl */
+ kprobe_per_regs[0].em_instruction_fetch = 1;
+ kprobe_per_regs[0].starting_addr = (unsigned long)p->ainsn.insn;
+ kprobe_per_regs[0].ending_addr = (unsigned long)p->ainsn.insn + 1;
+
+ /* Set the PER control regs, turns on single step for this address */
+ __ctl_load(kprobe_per_regs, 9, 11);
+ regs->psw.mask |= PSW_MASK_PER;
+ regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.kprobe_saved_imask = kcb->kprobe_saved_imask;
+ memcpy(kcb->prev_kprobe.kprobe_saved_ctl, kcb->kprobe_saved_ctl,
+ sizeof(kcb->kprobe_saved_ctl));
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_saved_imask = kcb->prev_kprobe.kprobe_saved_imask;
+ memcpy(kcb->kprobe_saved_ctl, kcb->prev_kprobe.kprobe_saved_ctl,
+ sizeof(kcb->kprobe_saved_ctl));
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ /* Save the interrupt and per flags */
+ kcb->kprobe_saved_imask = regs->psw.mask &
+ (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+ /* Save the control regs that govern PER */
+ __ctl_store(kcb->kprobe_saved_ctl, 9, 11);
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
+
+ /* Replace the return addr with trampoline addr */
+ regs->gprs[14] = (unsigned long)&kretprobe_trampoline;
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ int ret = 0;
+ unsigned long *addr = (unsigned long *)
+ ((regs->psw.addr & PSW_ADDR_INSN) - 2);
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Check we're not actually recursing */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS &&
+ *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
+ regs->psw.mask &= ~PSW_MASK_PER;
+ regs->psw.mask |= kcb->kprobe_saved_imask;
+ goto no_kprobe;
+ }
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else {
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ goto ss_probe;
+ }
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p)
+ /*
+ * No kprobe at this address. The fault has not been
+ * caused by a kprobe breakpoint. The race of breakpoint
+ * vs. kprobe remove does not exist because on s390 we
+ * use stop_machine_run to arm/disarm the breakpoints.
+ */
+ goto no_kprobe;
+
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+ set_current_kprobe(p, regs, kcb);
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /* handler has already set things up, so skip ss setup */
+ return 1;
+
+ss_probe:
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/*
+ * Function return probe trampoline:
+ * - init_kprobes() establishes a probepoint here
+ * - When the probed function returns, this probe
+ * causes the handlers to fire
+ */
+void kretprobe_trampoline_holder(void)
+{
+ asm volatile(".global kretprobe_trampoline\n"
+ "kretprobe_trampoline: bcr 0,0\n");
+}
+
+/*
+ * Called when the probe at kretprobe trampoline is hit
+ */
+static int __kprobes trampoline_probe_handler(struct kprobe *p,
+ struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(current);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because an multiple functions in the call path
+ * have a return probe installed on them, and/or more then one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address) {
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+ }
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+ regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;
+
+ reset_current_kprobe();
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ preempt_enable_no_resched();
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
+ */
+ return 1;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction whose first byte has been replaced by the "breakpoint"
+ * instruction. To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is p->ainsn.insn.
+ */
+static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ regs->psw.addr &= PSW_ADDR_INSN;
+
+ if (p->ainsn.fixup & FIXUP_PSW_NORMAL)
+ regs->psw.addr = (unsigned long)p->addr +
+ ((unsigned long)regs->psw.addr -
+ (unsigned long)p->ainsn.insn);
+
+ if (p->ainsn.fixup & FIXUP_BRANCH_NOT_TAKEN)
+ if ((unsigned long)regs->psw.addr -
+ (unsigned long)p->ainsn.insn == p->ainsn.ilen)
+ regs->psw.addr = (unsigned long)p->addr + p->ainsn.ilen;
+
+ if (p->ainsn.fixup & FIXUP_RETURN_REGISTER)
+ regs->gprs[p->ainsn.reg] = ((unsigned long)p->addr +
+ (regs->gprs[p->ainsn.reg] -
+ (unsigned long)p->ainsn.insn))
+ | PSW_ADDR_AMODE;
+
+ regs->psw.addr |= PSW_ADDR_AMODE;
+ /* turn off PER mode */
+ regs->psw.mask &= ~PSW_MASK_PER;
+ /* Restore the original per control regs */
+ __ctl_load(kcb->kprobe_saved_ctl, 9, 11);
+ regs->psw.mask |= kcb->kprobe_saved_imask;
+}
+
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs);
+
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ /*
+ * if somebody else is singlestepping across a probe point, psw mask
+ * will have PER set, in which case, continue the remaining processing
+ * of do_single_step, as if this is not a probe hit.
+ */
+ if (regs->psw.mask & PSW_MASK_PER) {
+ return 0;
+ }
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ const struct exception_table_entry *entry;
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_SWAP_INST:
+ /* We are here because the instruction replacement failed */
+ return 0;
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the nip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->psw.addr = (unsigned long)cur->addr | PSW_ADDR_AMODE;
+ regs->psw.mask &= ~PSW_MASK_PER;
+ regs->psw.mask |= kcb->kprobe_saved_imask;
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ entry = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
+ if (entry) {
+ regs->psw.addr = entry->fixup | PSW_ADDR_AMODE;
+ return 1;
+ }
+
+ /*
+ * fixup_exception() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ switch (val) {
+ case DIE_BPT:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_SSTEP:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_TRAP:
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() &&
+ kprobe_fault_handler(args->regs, args->trapnr))
+ ret = NOTIFY_STOP;
+ preempt_enable();
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ unsigned long addr;
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
+
+ /* setup return addr to the jprobe handler routine */
+ regs->psw.addr = (unsigned long)(jp->entry) | PSW_ADDR_AMODE;
+
+ /* r14 is the function return address */
+ kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14];
+ /* r15 is the stack pointer */
+ kcb->jprobe_saved_r15 = (unsigned long)regs->gprs[15];
+ addr = (unsigned long)kcb->jprobe_saved_r15;
+
+ memcpy(kcb->jprobes_stack, (kprobe_opcode_t *) addr,
+ MIN_STACK_SIZE(addr));
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ asm volatile(".word 0x0002");
+}
+
+void __kprobes jprobe_return_end(void)
+{
+ asm volatile("bcr 0,0");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_r15);
+
+ /* Put the regs back */
+ memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
+ /* put the stack back */
+ memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
+ MIN_STACK_SIZE(stack_addr));
+ preempt_enable_no_resched();
+ return 1;
+}
+
+static struct kprobe trampoline_p = {
+ .addr = (kprobe_opcode_t *) & kretprobe_trampoline,
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+ return register_kprobe(&trampoline_p);
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ if (p->addr == (kprobe_opcode_t *) & kretprobe_trampoline)
+ return 1;
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/s390/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/s390/kernel/kprobes.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,672 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2006
- *
- * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/preempt.h>
-#include <linux/stop_machine.h>
-#include <linux/kdebug.h>
-#include <asm/cacheflush.h>
-#include <asm/sections.h>
-#include <asm/uaccess.h>
-#include <linux/module.h>
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- /* Make sure the probe isn't going on a difficult instruction */
- if (is_prohibited_opcode((kprobe_opcode_t *) p->addr))
- return -EINVAL;
-
- if ((unsigned long)p->addr & 0x01) {
- printk("Attempt to register kprobe at an unaligned address\n");
- return -EINVAL;
- }
-
- /* Use the get_insn_slot() facility for correctness */
- if (!(p->ainsn.insn = get_insn_slot()))
- return -ENOMEM;
-
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
-
- get_instruction_type(&p->ainsn);
- p->opcode = *p->addr;
- return 0;
-}
-
-int __kprobes is_prohibited_opcode(kprobe_opcode_t *instruction)
-{
- switch (*(__u8 *) instruction) {
- case 0x0c: /* bassm */
- case 0x0b: /* bsm */
- case 0x83: /* diag */
- case 0x44: /* ex */
- return -EINVAL;
- }
- switch (*(__u16 *) instruction) {
- case 0x0101: /* pr */
- case 0xb25a: /* bsa */
- case 0xb240: /* bakr */
- case 0xb258: /* bsg */
- case 0xb218: /* pc */
- case 0xb228: /* pt */
- return -EINVAL;
- }
- return 0;
-}
-
-void __kprobes get_instruction_type(struct arch_specific_insn *ainsn)
-{
- /* default fixup method */
- ainsn->fixup = FIXUP_PSW_NORMAL;
-
- /* save r1 operand */
- ainsn->reg = (*ainsn->insn & 0xf0) >> 4;
-
- /* save the instruction length (pop 5-5) in bytes */
- switch (*(__u8 *) (ainsn->insn) >> 6) {
- case 0:
- ainsn->ilen = 2;
- break;
- case 1:
- case 2:
- ainsn->ilen = 4;
- break;
- case 3:
- ainsn->ilen = 6;
- break;
- }
-
- switch (*(__u8 *) ainsn->insn) {
- case 0x05: /* balr */
- case 0x0d: /* basr */
- ainsn->fixup = FIXUP_RETURN_REGISTER;
- /* if r2 = 0, no branch will be taken */
- if ((*ainsn->insn & 0x0f) == 0)
- ainsn->fixup |= FIXUP_BRANCH_NOT_TAKEN;
- break;
- case 0x06: /* bctr */
- case 0x07: /* bcr */
- ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
- break;
- case 0x45: /* bal */
- case 0x4d: /* bas */
- ainsn->fixup = FIXUP_RETURN_REGISTER;
- break;
- case 0x47: /* bc */
- case 0x46: /* bct */
- case 0x86: /* bxh */
- case 0x87: /* bxle */
- ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
- break;
- case 0x82: /* lpsw */
- ainsn->fixup = FIXUP_NOT_REQUIRED;
- break;
- case 0xb2: /* lpswe */
- if (*(((__u8 *) ainsn->insn) + 1) == 0xb2) {
- ainsn->fixup = FIXUP_NOT_REQUIRED;
- }
- break;
- case 0xa7: /* bras */
- if ((*ainsn->insn & 0x0f) == 0x05) {
- ainsn->fixup |= FIXUP_RETURN_REGISTER;
- }
- break;
- case 0xc0:
- if ((*ainsn->insn & 0x0f) == 0x00 /* larl */
- || (*ainsn->insn & 0x0f) == 0x05) /* brasl */
- ainsn->fixup |= FIXUP_RETURN_REGISTER;
- break;
- case 0xeb:
- if (*(((__u8 *) ainsn->insn) + 5 ) == 0x44 || /* bxhg */
- *(((__u8 *) ainsn->insn) + 5) == 0x45) {/* bxleg */
- ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
- }
- break;
- case 0xe3: /* bctg */
- if (*(((__u8 *) ainsn->insn) + 5) == 0x46) {
- ainsn->fixup = FIXUP_BRANCH_NOT_TAKEN;
- }
- break;
- }
-}
-
-static int __kprobes swap_instruction(void *aref)
-{
- struct ins_replace_args *args = aref;
- u32 *addr;
- u32 instr;
- int err = -EFAULT;
-
- /*
- * Text segment is read-only, hence we use stura to bypass dynamic
- * address translation to exchange the instruction. Since stura
- * always operates on four bytes, but we only want to exchange two
- * bytes do some calculations to get things right. In addition we
- * shall not cross any page boundaries (vmalloc area!) when writing
- * the new instruction.
- */
- addr = (u32 *)((unsigned long)args->ptr & -4UL);
- if ((unsigned long)args->ptr & 2)
- instr = ((*addr) & 0xffff0000) | args->new;
- else
- instr = ((*addr) & 0x0000ffff) | args->new << 16;
-
- asm volatile(
- " lra %1,0(%1)\n"
- "0: stura %2,%1\n"
- "1: la %0,0\n"
- "2:\n"
- EX_TABLE(0b,2b)
- : "+d" (err)
- : "a" (addr), "d" (instr)
- : "memory", "cc");
-
- return err;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- unsigned long status = kcb->kprobe_status;
- struct ins_replace_args args;
-
- args.ptr = p->addr;
- args.old = p->opcode;
- args.new = BREAKPOINT_INSTRUCTION;
-
- kcb->kprobe_status = KPROBE_SWAP_INST;
- stop_machine_run(swap_instruction, &args, NR_CPUS);
- kcb->kprobe_status = status;
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- unsigned long status = kcb->kprobe_status;
- struct ins_replace_args args;
-
- args.ptr = p->addr;
- args.old = BREAKPOINT_INSTRUCTION;
- args.new = p->opcode;
-
- kcb->kprobe_status = KPROBE_SWAP_INST;
- stop_machine_run(swap_instruction, &args, NR_CPUS);
- kcb->kprobe_status = status;
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- per_cr_bits kprobe_per_regs[1];
-
- memset(kprobe_per_regs, 0, sizeof(per_cr_bits));
- regs->psw.addr = (unsigned long)p->ainsn.insn | PSW_ADDR_AMODE;
-
- /* Set up the per control reg info, will pass to lctl */
- kprobe_per_regs[0].em_instruction_fetch = 1;
- kprobe_per_regs[0].starting_addr = (unsigned long)p->ainsn.insn;
- kprobe_per_regs[0].ending_addr = (unsigned long)p->ainsn.insn + 1;
-
- /* Set the PER control regs, turns on single step for this address */
- __ctl_load(kprobe_per_regs, 9, 11);
- regs->psw.mask |= PSW_MASK_PER;
- regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.kprobe_saved_imask = kcb->kprobe_saved_imask;
- memcpy(kcb->prev_kprobe.kprobe_saved_ctl, kcb->kprobe_saved_ctl,
- sizeof(kcb->kprobe_saved_ctl));
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_saved_imask = kcb->prev_kprobe.kprobe_saved_imask;
- memcpy(kcb->kprobe_saved_ctl, kcb->prev_kprobe.kprobe_saved_ctl,
- sizeof(kcb->kprobe_saved_ctl));
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- /* Save the interrupt and per flags */
- kcb->kprobe_saved_imask = regs->psw.mask &
- (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
- /* Save the control regs that govern PER */
- __ctl_store(kcb->kprobe_saved_ctl, 9, 11);
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
-
- /* Replace the return addr with trampoline addr */
- regs->gprs[14] = (unsigned long)&kretprobe_trampoline;
-}
-
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- int ret = 0;
- unsigned long *addr = (unsigned long *)
- ((regs->psw.addr & PSW_ADDR_INSN) - 2);
- struct kprobe_ctlblk *kcb;
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Check we're not actually recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
- regs->psw.mask &= ~PSW_MASK_PER;
- regs->psw.mask |= kcb->kprobe_saved_imask;
- goto no_kprobe;
- }
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- } else {
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p)
- /*
- * No kprobe at this address. The fault has not been
- * caused by a kprobe breakpoint. The race of breakpoint
- * vs. kprobe remove does not exist because on s390 we
- * use stop_machine_run to arm/disarm the breakpoints.
- */
- goto no_kprobe;
-
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- set_current_kprobe(p, regs, kcb);
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/*
- * Function return probe trampoline:
- * - init_kprobes() establishes a probepoint here
- * - When the probed function returns, this probe
- * causes the handlers to fire
- */
-void kretprobe_trampoline_holder(void)
-{
- asm volatile(".global kretprobe_trampoline\n"
- "kretprobe_trampoline: bcr 0,0\n");
-}
-
-/*
- * Called when the probe at kretprobe trampoline is hit
- */
-static int __kprobes trampoline_probe_handler(struct kprobe *p,
- struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler)
- ri->rp->handler(ri, regs);
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address) {
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
- }
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
- regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;
-
- reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- preempt_enable_no_resched();
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
- * to run (and have re-enabled preemption)
- */
- return 1;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the "breakpoint"
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is p->ainsn.insn.
- */
-static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- regs->psw.addr &= PSW_ADDR_INSN;
-
- if (p->ainsn.fixup & FIXUP_PSW_NORMAL)
- regs->psw.addr = (unsigned long)p->addr +
- ((unsigned long)regs->psw.addr -
- (unsigned long)p->ainsn.insn);
-
- if (p->ainsn.fixup & FIXUP_BRANCH_NOT_TAKEN)
- if ((unsigned long)regs->psw.addr -
- (unsigned long)p->ainsn.insn == p->ainsn.ilen)
- regs->psw.addr = (unsigned long)p->addr + p->ainsn.ilen;
-
- if (p->ainsn.fixup & FIXUP_RETURN_REGISTER)
- regs->gprs[p->ainsn.reg] = ((unsigned long)p->addr +
- (regs->gprs[p->ainsn.reg] -
- (unsigned long)p->ainsn.insn))
- | PSW_ADDR_AMODE;
-
- regs->psw.addr |= PSW_ADDR_AMODE;
- /* turn off PER mode */
- regs->psw.mask &= ~PSW_MASK_PER;
- /* Restore the original per control regs */
- __ctl_load(kcb->kprobe_saved_ctl, 9, 11);
- regs->psw.mask |= kcb->kprobe_saved_imask;
-}
-
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs);
-
- /*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- /*
- * if somebody else is singlestepping across a probe point, psw mask
- * will have PER set, in which case, continue the remaining processing
- * of do_single_step, as if this is not a probe hit.
- */
- if (regs->psw.mask & PSW_MASK_PER) {
- return 0;
- }
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- const struct exception_table_entry *entry;
-
- switch(kcb->kprobe_status) {
- case KPROBE_SWAP_INST:
- /* We are here because the instruction replacement failed */
- return 0;
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the nip points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->psw.addr = (unsigned long)cur->addr | PSW_ADDR_AMODE;
- regs->psw.mask &= ~PSW_MASK_PER;
- regs->psw.mask |= kcb->kprobe_saved_imask;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- entry = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
- if (entry) {
- regs->psw.addr = entry->fixup | PSW_ADDR_AMODE;
- return 1;
- }
-
- /*
- * fixup_exception() could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
- return 0;
-}
-
-/*
- * Wrapper routine to for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- switch (val) {
- case DIE_BPT:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_SSTEP:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_TRAP:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- ret = NOTIFY_STOP;
- preempt_enable();
- break;
- default:
- break;
- }
- return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
-
- /* setup return addr to the jprobe handler routine */
- regs->psw.addr = (unsigned long)(jp->entry) | PSW_ADDR_AMODE;
-
- /* r14 is the function return address */
- kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14];
- /* r15 is the stack pointer */
- kcb->jprobe_saved_r15 = (unsigned long)regs->gprs[15];
- addr = (unsigned long)kcb->jprobe_saved_r15;
-
- memcpy(kcb->jprobes_stack, (kprobe_opcode_t *) addr,
- MIN_STACK_SIZE(addr));
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- asm volatile(".word 0x0002");
-}
-
-void __kprobes jprobe_return_end(void)
-{
- asm volatile("bcr 0,0");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_r15);
-
- /* Put the regs back */
- memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
- /* put the stack back */
- memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
- preempt_enable_no_resched();
- return 1;
-}
-
-static struct kprobe trampoline_p = {
- .addr = (kprobe_opcode_t *) & kretprobe_trampoline,
- .pre_handler = trampoline_probe_handler
-};
-
-int __init arch_init_kprobes(void)
-{
- return register_kprobe(&trampoline_p);
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- if (p->addr == (kprobe_opcode_t *) & kretprobe_trampoline)
- return 1;
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/sparc64/instrumentation/kprobes.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/sparc64/instrumentation/kprobes.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,487 @@
+/* arch/sparc64/kernel/kprobes.c
+ *
+ * Copyright (C) 2004 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/kdebug.h>
+#include <asm/signal.h>
+#include <asm/cacheflush.h>
+#include <asm/uaccess.h>
+
+/* We do not have hardware single-stepping on sparc64.
+ * So we implement software single-stepping with breakpoint
+ * traps. The top-level scheme is similar to that used
+ * in the x86 kprobes implementation.
+ *
+ * In the kprobe->ainsn.insn[] array we store the original
+ * instruction at index zero and a break instruction at
+ * index one.
+ *
+ * When we hit a kprobe we:
+ * - Run the pre-handler
+ * - Remember "regs->tnpc" and interrupt level stored in
+ * "regs->tstate" so we can restore them later
+ * - Disable PIL interrupts
+ * - Set regs->tpc to point to kprobe->ainsn.insn[0]
+ * - Set regs->tnpc to point to kprobe->ainsn.insn[1]
+ * - Mark that we are actively in a kprobe
+ *
+ * At this point we wait for the second breakpoint at
+ * kprobe->ainsn.insn[1] to hit. When it does we:
+ * - Run the post-handler
+ * - Set regs->tpc to "remembered" regs->tnpc stored above,
+ * restore the PIL interrupt level in "regs->tstate" as well
+ * - Make any adjustments necessary to regs->tnpc in order
+ * to handle relative branches correctly. See below.
+ * - Mark that we are no longer actively in a kprobe.
+ */
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ p->ainsn.insn[0] = *p->addr;
+ flushi(&p->ainsn.insn[0]);
+
+ p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
+ flushi(&p->ainsn.insn[1]);
+
+ p->opcode = *p->addr;
+ return 0;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flushi(p->addr);
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ *p->addr = p->opcode;
+ flushi(p->addr);
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.orig_tnpc = kcb->kprobe_orig_tnpc;
+ kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_orig_tnpc = kcb->prev_kprobe.orig_tnpc;
+ kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_orig_tnpc = regs->tnpc;
+ kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ regs->tstate |= TSTATE_PIL;
+
+ /*single step inline, if it a breakpoint instruction*/
+ if (p->opcode == BREAKPOINT_INSTRUCTION) {
+ regs->tpc = (unsigned long) p->addr;
+ regs->tnpc = kcb->kprobe_orig_tnpc;
+ } else {
+ regs->tpc = (unsigned long) &p->ainsn.insn[0];
+ regs->tnpc = (unsigned long) &p->ainsn.insn[1];
+ }
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ void *addr = (void *) regs->tpc;
+ int ret = 0;
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS) {
+ regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
+ kcb->kprobe_orig_tstate_pil);
+ goto no_kprobe;
+ }
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ kcb->kprobe_status = KPROBE_REENTER;
+ prepare_singlestep(p, regs, kcb);
+ return 1;
+ } else {
+ if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ ret = 1;
+ goto no_kprobe;
+ }
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs))
+ goto ss_probe;
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ */
+ ret = 1;
+ }
+ /* Not one of ours: let kernel handle it */
+ goto no_kprobe;
+ }
+
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+ if (p->pre_handler && p->pre_handler(p, regs))
+ return 1;
+
+ss_probe:
+ prepare_singlestep(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/* If INSN is a relative control transfer instruction,
+ * return the corrected branch destination value.
+ *
+ * regs->tpc and regs->tnpc still hold the values of the
+ * program counters at the time of trap due to the execution
+ * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
+ *
+ */
+static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
+ struct pt_regs *regs)
+{
+ unsigned long real_pc = (unsigned long) p->addr;
+
+ /* Branch not taken, no mods necessary. */
+ if (regs->tnpc == regs->tpc + 0x4UL)
+ return real_pc + 0x8UL;
+
+ /* The three cases are call, branch w/prediction,
+ * and traditional branch.
+ */
+ if ((insn & 0xc0000000) == 0x40000000 ||
+ (insn & 0xc1c00000) == 0x00400000 ||
+ (insn & 0xc1c00000) == 0x00800000) {
+ unsigned long ainsn_addr;
+
+ ainsn_addr = (unsigned long) &p->ainsn.insn[0];
+
+ /* The instruction did all the work for us
+ * already, just apply the offset to the correct
+ * instruction location.
+ */
+ return (real_pc + (regs->tnpc - ainsn_addr));
+ }
+
+ /* It is jmpl or some other absolute PC modification instruction,
+ * leave NPC as-is.
+ */
+ return regs->tnpc;
+}
+
+/* If INSN is an instruction which writes it's PC location
+ * into a destination register, fix that up.
+ */
+static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
+ unsigned long real_pc)
+{
+ unsigned long *slot = NULL;
+
+ /* Simplest case is 'call', which always uses %o7 */
+ if ((insn & 0xc0000000) == 0x40000000) {
+ slot = &regs->u_regs[UREG_I7];
+ }
+
+ /* 'jmpl' encodes the register inside of the opcode */
+ if ((insn & 0xc1f80000) == 0x81c00000) {
+ unsigned long rd = ((insn >> 25) & 0x1f);
+
+ if (rd <= 15) {
+ slot = &regs->u_regs[rd];
+ } else {
+ /* Hard case, it goes onto the stack. */
+ flushw_all();
+
+ rd -= 16;
+ slot = (unsigned long *)
+ (regs->u_regs[UREG_FP] + STACK_BIAS);
+ slot += rd;
+ }
+ }
+ if (slot != NULL)
+ *slot = real_pc;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction which has been replaced by the breakpoint
+ * instruction. To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is &p->ainsn.insn[0].
+ *
+ * This function prepares to return from the post-single-step
+ * breakpoint trap.
+ */
+static void __kprobes resume_execution(struct kprobe *p,
+ struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+{
+ u32 insn = p->ainsn.insn[0];
+
+ regs->tnpc = relbranch_fixup(insn, p, regs);
+
+ /* This assignment must occur after relbranch_fixup() */
+ regs->tpc = kcb->kprobe_orig_tnpc;
+
+ retpc_fixup(regs, insn, (unsigned long) p->addr);
+
+ regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
+ kcb->kprobe_orig_tstate_pil);
+}
+
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs, kcb);
+
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ const struct exception_table_entry *entry;
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the tpc points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->tpc = (unsigned long)cur->addr;
+ regs->tnpc = kcb->kprobe_orig_tnpc;
+ regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
+ kcb->kprobe_orig_tstate_pil);
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+
+ entry = search_exception_tables(regs->tpc);
+ if (entry) {
+ regs->tpc = entry->fixup;
+ regs->tnpc = regs->tpc + 4;
+ return 1;
+ }
+
+ /*
+ * fixup_exception() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
+ switch (val) {
+ case DIE_DEBUG:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_DEBUG_2:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
+ struct pt_regs *regs)
+{
+ BUG_ON(trap_level != 0x170 && trap_level != 0x171);
+
+ if (user_mode(regs)) {
+ local_irq_enable();
+ bad_trap(regs, trap_level);
+ return;
+ }
+
+ /* trap_level == 0x170 --> ta 0x70
+ * trap_level == 0x171 --> ta 0x71
+ */
+ if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2,
+ (trap_level == 0x170) ? "debug" : "debug_2",
+ regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
+ bad_trap(regs, trap_level);
+}
+
+/* Jprobes support. */
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
+
+ regs->tpc = (unsigned long) jp->entry;
+ regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
+ regs->tstate |= TSTATE_PIL;
+
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ register unsigned long orig_fp asm("g1");
+
+ orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
+ __asm__ __volatile__("\n"
+"1: cmp %%sp, %0\n\t"
+ "blu,a,pt %%xcc, 1b\n\t"
+ " restore\n\t"
+ ".globl jprobe_return_trap_instruction\n"
+"jprobe_return_trap_instruction:\n\t"
+ "ta 0x70"
+ : /* no outputs */
+ : "r" (orig_fp));
+}
+
+extern void jprobe_return_trap_instruction(void);
+
+extern void __show_regs(struct pt_regs * regs);
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ u32 *addr = (u32 *) regs->tpc;
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (addr == (u32 *) jprobe_return_trap_instruction) {
+ memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
+ preempt_enable_no_resched();
+ return 1;
+ }
+ return 0;
+}
+
+/* architecture specific initialization */
+int arch_init_kprobes(void)
+{
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/sparc64/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/sparc64/kernel/kprobes.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,487 +0,0 @@
-/* arch/sparc64/kernel/kprobes.c
- *
- * Copyright (C) 2004 David S. Miller <davem@davemloft.net>
- */
-
-#include <linux/kernel.h>
-#include <linux/kprobes.h>
-#include <linux/module.h>
-#include <linux/kdebug.h>
-#include <asm/signal.h>
-#include <asm/cacheflush.h>
-#include <asm/uaccess.h>
-
-/* We do not have hardware single-stepping on sparc64.
- * So we implement software single-stepping with breakpoint
- * traps. The top-level scheme is similar to that used
- * in the x86 kprobes implementation.
- *
- * In the kprobe->ainsn.insn[] array we store the original
- * instruction at index zero and a break instruction at
- * index one.
- *
- * When we hit a kprobe we:
- * - Run the pre-handler
- * - Remember "regs->tnpc" and interrupt level stored in
- * "regs->tstate" so we can restore them later
- * - Disable PIL interrupts
- * - Set regs->tpc to point to kprobe->ainsn.insn[0]
- * - Set regs->tnpc to point to kprobe->ainsn.insn[1]
- * - Mark that we are actively in a kprobe
- *
- * At this point we wait for the second breakpoint at
- * kprobe->ainsn.insn[1] to hit. When it does we:
- * - Run the post-handler
- * - Set regs->tpc to "remembered" regs->tnpc stored above,
- * restore the PIL interrupt level in "regs->tstate" as well
- * - Make any adjustments necessary to regs->tnpc in order
- * to handle relative branches correctly. See below.
- * - Mark that we are no longer actively in a kprobe.
- */
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- p->ainsn.insn[0] = *p->addr;
- flushi(&p->ainsn.insn[0]);
-
- p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
- flushi(&p->ainsn.insn[1]);
-
- p->opcode = *p->addr;
- return 0;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- *p->addr = BREAKPOINT_INSTRUCTION;
- flushi(p->addr);
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- *p->addr = p->opcode;
- flushi(p->addr);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.orig_tnpc = kcb->kprobe_orig_tnpc;
- kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_orig_tnpc = kcb->prev_kprobe.orig_tnpc;
- kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- kcb->kprobe_orig_tnpc = regs->tnpc;
- kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- regs->tstate |= TSTATE_PIL;
-
- /*single step inline, if it a breakpoint instruction*/
- if (p->opcode == BREAKPOINT_INSTRUCTION) {
- regs->tpc = (unsigned long) p->addr;
- regs->tnpc = kcb->kprobe_orig_tnpc;
- } else {
- regs->tpc = (unsigned long) &p->ainsn.insn[0];
- regs->tnpc = (unsigned long) &p->ainsn.insn[1];
- }
-}
-
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- void *addr = (void *) regs->tpc;
- int ret = 0;
- struct kprobe_ctlblk *kcb;
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kcb->kprobe_status == KPROBE_HIT_SS) {
- regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
- kcb->kprobe_orig_tstate_pil);
- goto no_kprobe;
- }
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- kcb->kprobe_status = KPROBE_REENTER;
- prepare_singlestep(p, regs, kcb);
- return 1;
- } else {
- if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- ret = 1;
- goto no_kprobe;
- }
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs))
- goto ss_probe;
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- */
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
- goto no_kprobe;
- }
-
- set_current_kprobe(p, regs, kcb);
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
- return 1;
-
-ss_probe:
- prepare_singlestep(p, regs, kcb);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/* If INSN is a relative control transfer instruction,
- * return the corrected branch destination value.
- *
- * regs->tpc and regs->tnpc still hold the values of the
- * program counters at the time of trap due to the execution
- * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
- *
- */
-static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
- struct pt_regs *regs)
-{
- unsigned long real_pc = (unsigned long) p->addr;
-
- /* Branch not taken, no mods necessary. */
- if (regs->tnpc == regs->tpc + 0x4UL)
- return real_pc + 0x8UL;
-
- /* The three cases are call, branch w/prediction,
- * and traditional branch.
- */
- if ((insn & 0xc0000000) == 0x40000000 ||
- (insn & 0xc1c00000) == 0x00400000 ||
- (insn & 0xc1c00000) == 0x00800000) {
- unsigned long ainsn_addr;
-
- ainsn_addr = (unsigned long) &p->ainsn.insn[0];
-
- /* The instruction did all the work for us
- * already, just apply the offset to the correct
- * instruction location.
- */
- return (real_pc + (regs->tnpc - ainsn_addr));
- }
-
- /* It is jmpl or some other absolute PC modification instruction,
- * leave NPC as-is.
- */
- return regs->tnpc;
-}
-
-/* If INSN is an instruction which writes it's PC location
- * into a destination register, fix that up.
- */
-static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
- unsigned long real_pc)
-{
- unsigned long *slot = NULL;
-
- /* Simplest case is 'call', which always uses %o7 */
- if ((insn & 0xc0000000) == 0x40000000) {
- slot = &regs->u_regs[UREG_I7];
- }
-
- /* 'jmpl' encodes the register inside of the opcode */
- if ((insn & 0xc1f80000) == 0x81c00000) {
- unsigned long rd = ((insn >> 25) & 0x1f);
-
- if (rd <= 15) {
- slot = &regs->u_regs[rd];
- } else {
- /* Hard case, it goes onto the stack. */
- flushw_all();
-
- rd -= 16;
- slot = (unsigned long *)
- (regs->u_regs[UREG_FP] + STACK_BIAS);
- slot += rd;
- }
- }
- if (slot != NULL)
- *slot = real_pc;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction which has been replaced by the breakpoint
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is &p->ainsn.insn[0].
- *
- * This function prepares to return from the post-single-step
- * breakpoint trap.
- */
-static void __kprobes resume_execution(struct kprobe *p,
- struct pt_regs *regs, struct kprobe_ctlblk *kcb)
-{
- u32 insn = p->ainsn.insn[0];
-
- regs->tnpc = relbranch_fixup(insn, p, regs);
-
- /* This assignment must occur after relbranch_fixup() */
- regs->tpc = kcb->kprobe_orig_tnpc;
-
- retpc_fixup(regs, insn, (unsigned long) p->addr);
-
- regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
- kcb->kprobe_orig_tstate_pil);
-}
-
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs, kcb);
-
- /*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- const struct exception_table_entry *entry;
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the tpc points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->tpc = (unsigned long)cur->addr;
- regs->tnpc = kcb->kprobe_orig_tnpc;
- regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
- kcb->kprobe_orig_tstate_pil);
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
-
- entry = search_exception_tables(regs->tpc);
- if (entry) {
- regs->tpc = entry->fixup;
- regs->tnpc = regs->tpc + 4;
- return 1;
- }
-
- /*
- * fixup_exception() could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
-
- return 0;
-}
-
-/*
- * Wrapper routine to for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode(args->regs))
- return ret;
-
- switch (val) {
- case DIE_DEBUG:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_DEBUG_2:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- default:
- break;
- }
- return ret;
-}
-
-asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
- struct pt_regs *regs)
-{
- BUG_ON(trap_level != 0x170 && trap_level != 0x171);
-
- if (user_mode(regs)) {
- local_irq_enable();
- bad_trap(regs, trap_level);
- return;
- }
-
- /* trap_level == 0x170 --> ta 0x70
- * trap_level == 0x171 --> ta 0x71
- */
- if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2,
- (trap_level == 0x170) ? "debug" : "debug_2",
- regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
- bad_trap(regs, trap_level);
-}
-
-/* Jprobes support. */
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
-
- regs->tpc = (unsigned long) jp->entry;
- regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
- regs->tstate |= TSTATE_PIL;
-
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- register unsigned long orig_fp asm("g1");
-
- orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
- __asm__ __volatile__("\n"
-"1: cmp %%sp, %0\n\t"
- "blu,a,pt %%xcc, 1b\n\t"
- " restore\n\t"
- ".globl jprobe_return_trap_instruction\n"
-"jprobe_return_trap_instruction:\n\t"
- "ta 0x70"
- : /* no outputs */
- : "r" (orig_fp));
-}
-
-extern void jprobe_return_trap_instruction(void);
-
-extern void __show_regs(struct pt_regs * regs);
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- u32 *addr = (u32 *) regs->tpc;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (addr == (u32 *) jprobe_return_trap_instruction) {
- memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-
-/* architecture specific initialization */
-int arch_init_kprobes(void)
-{
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/avr32/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/avr32/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/avr32/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -1,3 +1,5 @@
#
# avr32 instrumentation Makefile
#
+
+obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/arch/avr32/kernel/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/avr32/kernel/Makefile 2007-10-29 09:51:07.000000000 -0400
+++ linux-2.6-lttng.stable/arch/avr32/kernel/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -10,4 +10,3 @@ obj-y += setup.o traps.o semaphore.o
obj-y += signal.o sys_avr32.o process.o time.o
obj-y += init_task.o switch_to.o cpu.o
obj-$(CONFIG_MODULES) += module.o avr32_ksyms.o
-obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/arch/ia64/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/ia64/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/ia64/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -8,3 +8,5 @@ DRIVER_OBJS := $(addprefix ../../../driv

oprofile-y := $(DRIVER_OBJS) init.o backtrace.o
oprofile-$(CONFIG_PERFMON) += perfmon.o
+
+obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
Index: linux-2.6-lttng.stable/arch/powerpc/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/powerpc/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/powerpc/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -17,3 +17,5 @@ oprofile-$(CONFIG_OPROFILE_CELL) += op_m
oprofile-$(CONFIG_PPC64) += op_model_rs64.o op_model_power4.o op_model_pa6t.o
oprofile-$(CONFIG_FSL_BOOKE) += op_model_fsl_booke.o
oprofile-$(CONFIG_6xx) += op_model_7450.o
+
+obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/arch/s390/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/s390/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/s390/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -7,3 +7,5 @@ DRIVER_OBJS = $(addprefix ../../../drive
timer_int.o )

oprofile-y := $(DRIVER_OBJS) init.o backtrace.o
+
+obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/arch/sparc64/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/sparc64/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/sparc64/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -7,3 +7,5 @@ DRIVER_OBJS = $(addprefix ../../../drive
timer_int.o )

oprofile-y := $(DRIVER_OBJS) init.o
+
+obj-$(CONFIG_KPROBES) += kprobes.o
Index: linux-2.6-lttng.stable/arch/x86/instrumentation/kprobes_32.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/x86/instrumentation/kprobes_32.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,763 @@
+/*
+ * Kernel Probes (KProbes)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ * Probes initial implementation ( includes contributions from
+ * Rusty Russell).
+ * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ * interface to access function arguments.
+ * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ * <prasanna@in.ibm.com> added function-return probes.
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/preempt.h>
+#include <linux/kdebug.h>
+#include <asm/cacheflush.h>
+#include <asm/desc.h>
+#include <asm/uaccess.h>
+#include <asm/alternative.h>
+
+void jprobe_return_end(void);
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {
+ {"__switch_to", }, /* This function switches only current task, but
+ doesn't switch kernel stack.*/
+ {NULL, NULL} /* Terminator */
+};
+const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
+
+/* insert a jmp code */
+static __always_inline void set_jmp_op(void *from, void *to)
+{
+ struct __arch_jmp_op {
+ char op;
+ long raddr;
+ } __attribute__((packed)) *jop;
+ jop = (struct __arch_jmp_op *)from;
+ jop->raddr = (long)(to) - ((long)(from) + 5);
+ jop->op = RELATIVEJUMP_INSTRUCTION;
+}
+
+/*
+ * returns non-zero if opcodes can be boosted.
+ */
+static __always_inline int can_boost(kprobe_opcode_t *opcodes)
+{
+#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
+ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
+ (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
+ (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
+ (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
+ << (row % 32))
+ /*
+ * Undefined/reserved opcodes, conditional jump, Opcode Extension
+ * Groups, and some special opcodes can not be boost.
+ */
+ static const unsigned long twobyte_is_boostable[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ------------------------------- */
+ W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
+ W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
+ W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
+ W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
+ W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
+ W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
+ W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
+ W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
+ W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
+ W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
+ W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
+ W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
+ W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
+ W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
+ W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
+ W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
+ /* ------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ };
+#undef W
+ kprobe_opcode_t opcode;
+ kprobe_opcode_t *orig_opcodes = opcodes;
+retry:
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ opcode = *(opcodes++);
+
+ /* 2nd-byte opcode */
+ if (opcode == 0x0f) {
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ return test_bit(*opcodes, twobyte_is_boostable);
+ }
+
+ switch (opcode & 0xf0) {
+ case 0x60:
+ if (0x63 < opcode && opcode < 0x67)
+ goto retry; /* prefixes */
+ /* can't boost Address-size override and bound */
+ return (opcode != 0x62 && opcode != 0x67);
+ case 0x70:
+ return 0; /* can't boost conditional jump */
+ case 0xc0:
+ /* can't boost software-interruptions */
+ return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
+ case 0xd0:
+ /* can boost AA* and XLAT */
+ return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
+ case 0xe0:
+ /* can boost in/out and absolute jmps */
+ return ((opcode & 0x04) || opcode == 0xea);
+ case 0xf0:
+ if ((opcode & 0x0c) == 0 && opcode != 0xf1)
+ goto retry; /* lock/rep(ne) prefix */
+ /* clear and set flags can be boost */
+ return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
+ default:
+ if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
+ goto retry; /* prefixes */
+ /* can't boost CS override and call */
+ return (opcode != 0x2e && opcode != 0x9a);
+ }
+}
+
+/*
+ * returns non-zero if opcode modifies the interrupt flag.
+ */
+static int __kprobes is_IF_modifier(kprobe_opcode_t opcode)
+{
+ switch (opcode) {
+ case 0xfa: /* cli */
+ case 0xfb: /* sti */
+ case 0xcf: /* iret/iretd */
+ case 0x9d: /* popf/popfd */
+ return 1;
+ }
+ return 0;
+}
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ /* insn: must be on special executable page on i386. */
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ p->opcode = *p->addr;
+ if (can_boost(p->addr)) {
+ p->ainsn.boostable = 0;
+ } else {
+ p->ainsn.boostable = -1;
+ }
+ return 0;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ text_poke(p->addr, &p->opcode, 1);
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
+ mutex_unlock(&kprobe_mutex);
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags;
+ kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags;
+ kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags
+ = (regs->eflags & (TF_MASK | IF_MASK));
+ if (is_IF_modifier(p->opcode))
+ kcb->kprobe_saved_eflags &= ~IF_MASK;
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ regs->eflags |= TF_MASK;
+ regs->eflags &= ~IF_MASK;
+ /*single step inline if the instruction is an int3*/
+ if (p->opcode == BREAKPOINT_INSTRUCTION)
+ regs->eip = (unsigned long)p->addr;
+ else
+ regs->eip = (unsigned long)p->ainsn.insn;
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ unsigned long *sara = (unsigned long *)&regs->esp;
+
+ ri->ret_addr = (kprobe_opcode_t *) *sara;
+
+ /* Replace the return addr with trampoline addr */
+ *sara = (unsigned long) &kretprobe_trampoline;
+}
+
+/*
+ * Interrupts are disabled on entry as trap3 is an interrupt gate and they
+ * remain disabled thorough out this function.
+ */
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ int ret = 0;
+ kprobe_opcode_t *addr;
+ struct kprobe_ctlblk *kcb;
+
+ addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Check we're not actually recursing */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS &&
+ *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
+ regs->eflags &= ~TF_MASK;
+ regs->eflags |= kcb->kprobe_saved_eflags;
+ goto no_kprobe;
+ }
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the handler.
+ * We here save the original kprobes variables and
+ * just single step on the instruction of the new probe
+ * without calling any user handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ } else {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ regs->eip -= sizeof(kprobe_opcode_t);
+ ret = 1;
+ goto no_kprobe;
+ }
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ goto ss_probe;
+ }
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Back up over the (now missing) int3 and run
+ * the original instruction.
+ */
+ regs->eip -= sizeof(kprobe_opcode_t);
+ ret = 1;
+ }
+ /* Not one of ours: let kernel handle it */
+ goto no_kprobe;
+ }
+
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /* handler has already set things up, so skip ss setup */
+ return 1;
+
+ss_probe:
+#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
+ if (p->ainsn.boostable == 1 && !p->post_handler){
+ /* Boost up -- we can execute copied instructions directly */
+ reset_current_kprobe();
+ regs->eip = (unsigned long)p->ainsn.insn;
+ preempt_enable_no_resched();
+ return 1;
+ }
+#endif
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/*
+ * For function-return probes, init_kprobes() establishes a probepoint
+ * here. When a retprobed function returns, this probe is hit and
+ * trampoline_probe_handler() runs, calling the kretprobe's handler.
+ */
+ void __kprobes kretprobe_trampoline_holder(void)
+ {
+ asm volatile ( ".global kretprobe_trampoline\n"
+ "kretprobe_trampoline: \n"
+ " pushf\n"
+ /* skip cs, eip, orig_eax */
+ " subl $12, %esp\n"
+ " pushl %fs\n"
+ " pushl %ds\n"
+ " pushl %es\n"
+ " pushl %eax\n"
+ " pushl %ebp\n"
+ " pushl %edi\n"
+ " pushl %esi\n"
+ " pushl %edx\n"
+ " pushl %ecx\n"
+ " pushl %ebx\n"
+ " movl %esp, %eax\n"
+ " call trampoline_handler\n"
+ /* move eflags to cs */
+ " movl 52(%esp), %edx\n"
+ " movl %edx, 48(%esp)\n"
+ /* save true return address on eflags */
+ " movl %eax, 52(%esp)\n"
+ " popl %ebx\n"
+ " popl %ecx\n"
+ " popl %edx\n"
+ " popl %esi\n"
+ " popl %edi\n"
+ " popl %ebp\n"
+ " popl %eax\n"
+ /* skip eip, orig_eax, es, ds, fs */
+ " addl $20, %esp\n"
+ " popf\n"
+ " ret\n");
+}
+
+/*
+ * Called from kretprobe_trampoline
+ */
+fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(current);
+ /* fixup registers */
+ regs->xcs = __KERNEL_CS | get_kernel_rpl();
+ regs->eip = trampoline_address;
+ regs->orig_eax = 0xffffffff;
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because an multiple functions in the call path
+ * have a return probe installed on them, and/or more then one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler){
+ __get_cpu_var(current_kprobe) = &ri->rp->kp;
+ get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
+ ri->rp->handler(ri, regs);
+ __get_cpu_var(current_kprobe) = NULL;
+ }
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ return (void*)orig_ret_address;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction whose first byte has been replaced by the "int 3"
+ * instruction. To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is p->ainsn.insn.
+ *
+ * This function prepares to return from the post-single-step
+ * interrupt. We have to fix up the stack as follows:
+ *
+ * 0) Except in the case of absolute or indirect jump or call instructions,
+ * the new eip is relative to the copied instruction. We need to make
+ * it relative to the original instruction.
+ *
+ * 1) If the single-stepped instruction was pushfl, then the TF and IF
+ * flags are set in the just-pushed eflags, and may need to be cleared.
+ *
+ * 2) If the single-stepped instruction was a call, the return address
+ * that is atop the stack is the address following the copied instruction.
+ * We need to make it the address following the original instruction.
+ *
+ * This function also checks instruction size for preparing direct execution.
+ */
+static void __kprobes resume_execution(struct kprobe *p,
+ struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+{
+ unsigned long *tos = (unsigned long *)&regs->esp;
+ unsigned long copy_eip = (unsigned long)p->ainsn.insn;
+ unsigned long orig_eip = (unsigned long)p->addr;
+
+ regs->eflags &= ~TF_MASK;
+ switch (p->ainsn.insn[0]) {
+ case 0x9c: /* pushfl */
+ *tos &= ~(TF_MASK | IF_MASK);
+ *tos |= kcb->kprobe_old_eflags;
+ break;
+ case 0xc2: /* iret/ret/lret */
+ case 0xc3:
+ case 0xca:
+ case 0xcb:
+ case 0xcf:
+ case 0xea: /* jmp absolute -- eip is correct */
+ /* eip is already adjusted, no more changes required */
+ p->ainsn.boostable = 1;
+ goto no_change;
+ case 0xe8: /* call relative - Fix return addr */
+ *tos = orig_eip + (*tos - copy_eip);
+ break;
+ case 0x9a: /* call absolute -- same as call absolute, indirect */
+ *tos = orig_eip + (*tos - copy_eip);
+ goto no_change;
+ case 0xff:
+ if ((p->ainsn.insn[1] & 0x30) == 0x10) {
+ /*
+ * call absolute, indirect
+ * Fix return addr; eip is correct.
+ * But this is not boostable
+ */
+ *tos = orig_eip + (*tos - copy_eip);
+ goto no_change;
+ } else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
+ ((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
+ /* eip is correct. And this is boostable */
+ p->ainsn.boostable = 1;
+ goto no_change;
+ }
+ default:
+ break;
+ }
+
+ if (p->ainsn.boostable == 0) {
+ if ((regs->eip > copy_eip) &&
+ (regs->eip - copy_eip) + 5 < MAX_INSN_SIZE) {
+ /*
+ * These instructions can be executed directly if it
+ * jumps back to correct address.
+ */
+ set_jmp_op((void *)regs->eip,
+ (void *)orig_eip + (regs->eip - copy_eip));
+ p->ainsn.boostable = 1;
+ } else {
+ p->ainsn.boostable = -1;
+ }
+ }
+
+ regs->eip = orig_eip + (regs->eip - copy_eip);
+
+no_change:
+ return;
+}
+
+/*
+ * Interrupts are disabled on entry as trap1 is an interrupt gate and they
+ * remain disabled thoroughout this function.
+ */
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs, kcb);
+ regs->eflags |= kcb->kprobe_saved_eflags;
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+ if (raw_irqs_disabled_flags(regs->eflags))
+ trace_hardirqs_off();
+ else
+ trace_hardirqs_on();
+#endif
+
+ /*Restore back the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ /*
+ * if somebody else is singlestepping across a probe point, eflags
+ * will have TF set, in which case, continue the remaining processing
+ * of do_debug, as if this is not a probe hit.
+ */
+ if (regs->eflags & TF_MASK)
+ return 0;
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the eip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->eip = (unsigned long)cur->addr;
+ regs->eflags |= kcb->kprobe_old_eflags;
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ if (fixup_exception(regs))
+ return 1;
+
+ /*
+ * fixup_exception() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ if (args->regs && user_mode_vm(args->regs))
+ return ret;
+
+ switch (val) {
+ case DIE_INT3:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_DEBUG:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_GPF:
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() &&
+ kprobe_fault_handler(args->regs, args->trapnr))
+ ret = NOTIFY_STOP;
+ preempt_enable();
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ unsigned long addr;
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ kcb->jprobe_saved_regs = *regs;
+ kcb->jprobe_saved_esp = &regs->esp;
+ addr = (unsigned long)(kcb->jprobe_saved_esp);
+
+ /*
+ * TBD: As Linus pointed out, gcc assumes that the callee
+ * owns the argument space and could overwrite it, e.g.
+ * tailcall optimization. So, to be absolutely safe
+ * we also save and restore enough stack bytes to cover
+ * the argument area.
+ */
+ memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
+ MIN_STACK_SIZE(addr));
+ regs->eflags &= ~IF_MASK;
+ trace_hardirqs_off();
+ regs->eip = (unsigned long)(jp->entry);
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ asm volatile (" xchgl %%ebx,%%esp \n"
+ " int3 \n"
+ " .globl jprobe_return_end \n"
+ " jprobe_return_end: \n"
+ " nop \n"::"b"
+ (kcb->jprobe_saved_esp):"memory");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ u8 *addr = (u8 *) (regs->eip - 1);
+ unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp);
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+
+ if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
+ if (&regs->esp != kcb->jprobe_saved_esp) {
+ struct pt_regs *saved_regs =
+ container_of(kcb->jprobe_saved_esp,
+ struct pt_regs, esp);
+ printk("current esp %p does not match saved esp %p\n",
+ &regs->esp, kcb->jprobe_saved_esp);
+ printk("Saved registers for jprobe %p\n", jp);
+ show_registers(saved_regs);
+ printk("Current registers\n");
+ show_registers(regs);
+ BUG();
+ }
+ *regs = kcb->jprobe_saved_regs;
+ memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
+ MIN_STACK_SIZE(stack_addr));
+ preempt_enable_no_resched();
+ return 1;
+ }
+ return 0;
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ return 0;
+}
+
+int __init arch_init_kprobes(void)
+{
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/x86/instrumentation/kprobes_64.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/arch/x86/instrumentation/kprobes_64.c 2007-10-29 09:51:38.000000000 -0400
@@ -0,0 +1,761 @@
+/*
+ * Kernel Probes (KProbes)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ * Probes initial implementation ( includes contributions from
+ * Rusty Russell).
+ * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ * interface to access function arguments.
+ * 2004-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi
+ * <prasanna@in.ibm.com> adapted for x86_64
+ * 2005-Mar Roland McGrath <roland@redhat.com>
+ * Fixed to handle %rip-relative addressing mode correctly.
+ * 2005-May Rusty Lynch <rusty.lynch@intel.com>
+ * Added function return probes functionality
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/module.h>
+#include <linux/kdebug.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/alternative.h>
+
+void jprobe_return_end(void);
+static void __kprobes arch_copy_kprobe(struct kprobe *p);
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+struct kretprobe_blackpoint kretprobe_blacklist[] = {
+ {"__switch_to", }, /* This function switches only current task, but
+ doesn't switch kernel stack.*/
+ {NULL, NULL} /* Terminator */
+};
+const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
+
+/*
+ * returns non-zero if opcode modifies the interrupt flag.
+ */
+static __always_inline int is_IF_modifier(kprobe_opcode_t *insn)
+{
+ switch (*insn) {
+ case 0xfa: /* cli */
+ case 0xfb: /* sti */
+ case 0xcf: /* iret/iretd */
+ case 0x9d: /* popf/popfd */
+ return 1;
+ }
+
+ if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf)
+ return 1;
+ return 0;
+}
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ /* insn: must be on special executable page on x86_64. */
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn) {
+ return -ENOMEM;
+ }
+ arch_copy_kprobe(p);
+ return 0;
+}
+
+/*
+ * Determine if the instruction uses the %rip-relative addressing mode.
+ * If it does, return the address of the 32-bit displacement word.
+ * If not, return null.
+ */
+static s32 __kprobes *is_riprel(u8 *insn)
+{
+#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
+ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
+ (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
+ (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
+ (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
+ << (row % 64))
+ static const u64 onebyte_has_modrm[256 / 64] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ------------------------------- */
+ W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */
+ W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */
+ W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */
+ W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */
+ W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */
+ W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */
+ W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */
+ W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */
+ W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */
+ W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */
+ W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */
+ W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */
+ W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */
+ W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */
+ W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */
+ W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */
+ /* ------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ };
+ static const u64 twobyte_has_modrm[256 / 64] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ------------------------------- */
+ W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */
+ W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */
+ W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */
+ W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */
+ W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */
+ W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */
+ W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */
+ W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */
+ W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */
+ W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */
+ W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */
+ W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */
+ W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */
+ W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */
+ W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */
+ W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */
+ /* ------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ };
+#undef W
+ int need_modrm;
+
+ /* Skip legacy instruction prefixes. */
+ while (1) {
+ switch (*insn) {
+ case 0x66:
+ case 0x67:
+ case 0x2e:
+ case 0x3e:
+ case 0x26:
+ case 0x64:
+ case 0x65:
+ case 0x36:
+ case 0xf0:
+ case 0xf3:
+ case 0xf2:
+ ++insn;
+ continue;
+ }
+ break;
+ }
+
+ /* Skip REX instruction prefix. */
+ if ((*insn & 0xf0) == 0x40)
+ ++insn;
+
+ if (*insn == 0x0f) { /* Two-byte opcode. */
+ ++insn;
+ need_modrm = test_bit(*insn, twobyte_has_modrm);
+ } else { /* One-byte opcode. */
+ need_modrm = test_bit(*insn, onebyte_has_modrm);
+ }
+
+ if (need_modrm) {
+ u8 modrm = *++insn;
+ if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
+ /* Displacement follows ModRM byte. */
+ return (s32 *) ++insn;
+ }
+ }
+
+ /* No %rip-relative addressing mode here. */
+ return NULL;
+}
+
+static void __kprobes arch_copy_kprobe(struct kprobe *p)
+{
+ s32 *ripdisp;
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
+ ripdisp = is_riprel(p->ainsn.insn);
+ if (ripdisp) {
+ /*
+ * The copied instruction uses the %rip-relative
+ * addressing mode. Adjust the displacement for the
+ * difference between the original location of this
+ * instruction and the location of the copy that will
+ * actually be run. The tricky bit here is making sure
+ * that the sign extension happens correctly in this
+ * calculation, since we need a signed 32-bit result to
+ * be sign-extended to 64 bits when it's added to the
+ * %rip value and yield the same 64-bit result that the
+ * sign-extension of the original signed 32-bit
+ * displacement would have given.
+ */
+ s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn;
+ BUG_ON((s64) (s32) disp != disp); /* Sanity check. */
+ *ripdisp = disp;
+ }
+ p->opcode = *p->addr;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ text_poke(p->addr, &p->opcode, 1);
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, 0);
+ mutex_unlock(&kprobe_mutex);
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.old_rflags = kcb->kprobe_old_rflags;
+ kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_old_rflags = kcb->prev_kprobe.old_rflags;
+ kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_saved_rflags = kcb->kprobe_old_rflags
+ = (regs->eflags & (TF_MASK | IF_MASK));
+ if (is_IF_modifier(p->ainsn.insn))
+ kcb->kprobe_saved_rflags &= ~IF_MASK;
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+ regs->eflags |= TF_MASK;
+ regs->eflags &= ~IF_MASK;
+ /*single step inline if the instruction is an int3*/
+ if (p->opcode == BREAKPOINT_INSTRUCTION)
+ regs->rip = (unsigned long)p->addr;
+ else
+ regs->rip = (unsigned long)p->ainsn.insn;
+}
+
+/* Called with kretprobe_lock held */
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ unsigned long *sara = (unsigned long *)regs->rsp;
+
+ ri->ret_addr = (kprobe_opcode_t *) *sara;
+ /* Replace the return addr with trampoline addr */
+ *sara = (unsigned long) &kretprobe_trampoline;
+}
+
+int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *p;
+ int ret = 0;
+ kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->rip - sizeof(kprobe_opcode_t));
+ struct kprobe_ctlblk *kcb;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
+
+ /* Check we're not actually recursing */
+ if (kprobe_running()) {
+ p = get_kprobe(addr);
+ if (p) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS &&
+ *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
+ regs->eflags &= ~TF_MASK;
+ regs->eflags |= kcb->kprobe_saved_rflags;
+ goto no_kprobe;
+ } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
+ /* TODO: Provide re-entrancy from
+ * post_kprobes_handler() and avoid exception
+ * stack corruption while single-stepping on
+ * the instruction of the new probe.
+ */
+ arch_disarm_kprobe(p);
+ regs->rip = (unsigned long)p->addr;
+ reset_current_kprobe();
+ ret = 1;
+ } else {
+ /* We have reentered the kprobe_handler(), since
+ * another probe was hit while within the
+ * handler. We here save the original kprobe
+ * variables and just single step on instruction
+ * of the new probe without calling any user
+ * handlers.
+ */
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ return 1;
+ }
+ } else {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /* The breakpoint instruction was removed by
+ * another cpu right after we hit, no further
+ * handling of this interrupt is appropriate
+ */
+ regs->rip = (unsigned long)addr;
+ ret = 1;
+ goto no_kprobe;
+ }
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ goto ss_probe;
+ }
+ }
+ goto no_kprobe;
+ }
+
+ p = get_kprobe(addr);
+ if (!p) {
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Back up over the (now missing) int3 and run
+ * the original instruction.
+ */
+ regs->rip = (unsigned long)addr;
+ ret = 1;
+ }
+ /* Not one of ours: let kernel handle it */
+ goto no_kprobe;
+ }
+
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ if (p->pre_handler && p->pre_handler(p, regs))
+ /* handler has already set things up, so skip ss setup */
+ return 1;
+
+ss_probe:
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ return 1;
+
+no_kprobe:
+ preempt_enable_no_resched();
+ return ret;
+}
+
+/*
+ * For function-return probes, init_kprobes() establishes a probepoint
+ * here. When a retprobed function returns, this probe is hit and
+ * trampoline_probe_handler() runs, calling the kretprobe's handler.
+ */
+ void kretprobe_trampoline_holder(void)
+ {
+ asm volatile ( ".global kretprobe_trampoline\n"
+ "kretprobe_trampoline: \n"
+ "nop\n");
+ }
+
+/*
+ * Called when we hit the probe point at kretprobe_trampoline
+ */
+int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ spin_lock_irqsave(&kretprobe_lock, flags);
+ head = kretprobe_inst_table_head(current);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because an multiple functions in the call path
+ * have a return probe installed on them, and/or more then one return
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always inserted at the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the first instance's ret_addr will point to the
+ * real return address, and all the rest will point to
+ * kretprobe_trampoline
+ */
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ if (ri->rp && ri->rp->handler)
+ ri->rp->handler(ri, regs);
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+ regs->rip = orig_ret_address;
+
+ reset_current_kprobe();
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ preempt_enable_no_resched();
+
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
+ */
+ return 1;
+}
+
+/*
+ * Called after single-stepping. p->addr is the address of the
+ * instruction whose first byte has been replaced by the "int 3"
+ * instruction. To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction. The address of this
+ * copy is p->ainsn.insn.
+ *
+ * This function prepares to return from the post-single-step
+ * interrupt. We have to fix up the stack as follows:
+ *
+ * 0) Except in the case of absolute or indirect jump or call instructions,
+ * the new rip is relative to the copied instruction. We need to make
+ * it relative to the original instruction.
+ *
+ * 1) If the single-stepped instruction was pushfl, then the TF and IF
+ * flags are set in the just-pushed eflags, and may need to be cleared.
+ *
+ * 2) If the single-stepped instruction was a call, the return address
+ * that is atop the stack is the address following the copied instruction.
+ * We need to make it the address following the original instruction.
+ */
+static void __kprobes resume_execution(struct kprobe *p,
+ struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+{
+ unsigned long *tos = (unsigned long *)regs->rsp;
+ unsigned long next_rip = 0;
+ unsigned long copy_rip = (unsigned long)p->ainsn.insn;
+ unsigned long orig_rip = (unsigned long)p->addr;
+ kprobe_opcode_t *insn = p->ainsn.insn;
+
+ /*skip the REX prefix*/
+ if (*insn >= 0x40 && *insn <= 0x4f)
+ insn++;
+
+ switch (*insn) {
+ case 0x9c: /* pushfl */
+ *tos &= ~(TF_MASK | IF_MASK);
+ *tos |= kcb->kprobe_old_rflags;
+ break;
+ case 0xc3: /* ret/lret */
+ case 0xcb:
+ case 0xc2:
+ case 0xca:
+ regs->eflags &= ~TF_MASK;
+ /* rip is already adjusted, no more changes required*/
+ return;
+ case 0xe8: /* call relative - Fix return addr */
+ *tos = orig_rip + (*tos - copy_rip);
+ break;
+ case 0xff:
+ if ((insn[1] & 0x30) == 0x10) {
+ /* call absolute, indirect */
+ /* Fix return addr; rip is correct. */
+ next_rip = regs->rip;
+ *tos = orig_rip + (*tos - copy_rip);
+ } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
+ ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
+ /* rip is correct. */
+ next_rip = regs->rip;
+ }
+ break;
+ case 0xea: /* jmp absolute -- rip is correct */
+ next_rip = regs->rip;
+ break;
+ default:
+ break;
+ }
+
+ regs->eflags &= ~TF_MASK;
+ if (next_rip) {
+ regs->rip = next_rip;
+ } else {
+ regs->rip = orig_rip + (regs->rip - copy_rip);
+ }
+}
+
+int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
+ return 0;
+
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
+
+ resume_execution(cur, regs, kcb);
+ regs->eflags |= kcb->kprobe_saved_rflags;
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+ if (raw_irqs_disabled_flags(regs->eflags))
+ trace_hardirqs_off();
+ else
+ trace_hardirqs_on();
+#endif
+
+ /* Restore the original saved kprobes variables and continue. */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ goto out;
+ }
+ reset_current_kprobe();
+out:
+ preempt_enable_no_resched();
+
+ /*
+ * if somebody else is singlestepping across a probe point, eflags
+ * will have TF set, in which case, continue the remaining processing
+ * of do_debug, as if this is not a probe hit.
+ */
+ if (regs->eflags & TF_MASK)
+ return 0;
+
+ return 1;
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ const struct exception_table_entry *fixup;
+
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the rip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->rip = (unsigned long)cur->addr;
+ regs->eflags |= kcb->kprobe_old_rflags;
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+ preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ fixup = search_exception_tables(regs->rip);
+ if (fixup) {
+ regs->rip = fixup->fixup;
+ return 1;
+ }
+
+ /*
+ * fixup() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Wrapper routine for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = (struct die_args *)data;
+ int ret = NOTIFY_DONE;
+
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
+ switch (val) {
+ case DIE_INT3:
+ if (kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_DEBUG:
+ if (post_kprobe_handler(args->regs))
+ ret = NOTIFY_STOP;
+ break;
+ case DIE_GPF:
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() &&
+ kprobe_fault_handler(args->regs, args->trapnr))
+ ret = NOTIFY_STOP;
+ preempt_enable();
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+ unsigned long addr;
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ kcb->jprobe_saved_regs = *regs;
+ kcb->jprobe_saved_rsp = (long *) regs->rsp;
+ addr = (unsigned long)(kcb->jprobe_saved_rsp);
+ /*
+ * As Linus pointed out, gcc assumes that the callee
+ * owns the argument space and could overwrite it, e.g.
+ * tailcall optimization. So, to be absolutely safe
+ * we also save and restore enough stack bytes to cover
+ * the argument area.
+ */
+ memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
+ MIN_STACK_SIZE(addr));
+ regs->eflags &= ~IF_MASK;
+ trace_hardirqs_off();
+ regs->rip = (unsigned long)(jp->entry);
+ return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ asm volatile (" xchg %%rbx,%%rsp \n"
+ " int3 \n"
+ " .globl jprobe_return_end \n"
+ " jprobe_return_end: \n"
+ " nop \n"::"b"
+ (kcb->jprobe_saved_rsp):"memory");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ u8 *addr = (u8 *) (regs->rip - 1);
+ unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_rsp);
+ struct jprobe *jp = container_of(p, struct jprobe, kp);
+
+ if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
+ if ((long *)regs->rsp != kcb->jprobe_saved_rsp) {
+ struct pt_regs *saved_regs =
+ container_of(kcb->jprobe_saved_rsp,
+ struct pt_regs, rsp);
+ printk("current rsp %p does not match saved rsp %p\n",
+ (long *)regs->rsp, kcb->jprobe_saved_rsp);
+ printk("Saved registers for jprobe %p\n", jp);
+ show_registers(saved_regs);
+ printk("Current registers\n");
+ show_registers(regs);
+ BUG();
+ }
+ *regs = kcb->jprobe_saved_regs;
+ memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
+ MIN_STACK_SIZE(stack_addr));
+ preempt_enable_no_resched();
+ return 1;
+ }
+ return 0;
+}
+
+static struct kprobe trampoline_p = {
+ .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+ .pre_handler = trampoline_probe_handler
+};
+
+int __init arch_init_kprobes(void)
+{
+ return register_kprobe(&trampoline_p);
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+ return 1;
+
+ return 0;
+}
Index: linux-2.6-lttng.stable/arch/x86/kernel/kprobes_32.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/x86/kernel/kprobes_32.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,763 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- * Probes initial implementation ( includes contributions from
- * Rusty Russell).
- * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- * interface to access function arguments.
- * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
- * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
- * <prasanna@in.ibm.com> added function-return probes.
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/preempt.h>
-#include <linux/kdebug.h>
-#include <asm/cacheflush.h>
-#include <asm/desc.h>
-#include <asm/uaccess.h>
-#include <asm/alternative.h>
-
-void jprobe_return_end(void);
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {
- {"__switch_to", }, /* This function switches only current task, but
- doesn't switch kernel stack.*/
- {NULL, NULL} /* Terminator */
-};
-const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
-
-/* insert a jmp code */
-static __always_inline void set_jmp_op(void *from, void *to)
-{
- struct __arch_jmp_op {
- char op;
- long raddr;
- } __attribute__((packed)) *jop;
- jop = (struct __arch_jmp_op *)from;
- jop->raddr = (long)(to) - ((long)(from) + 5);
- jop->op = RELATIVEJUMP_INSTRUCTION;
-}
-
-/*
- * returns non-zero if opcodes can be boosted.
- */
-static __always_inline int can_boost(kprobe_opcode_t *opcodes)
-{
-#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
- (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
- (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
- (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
- (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
- << (row % 32))
- /*
- * Undefined/reserved opcodes, conditional jump, Opcode Extension
- * Groups, and some special opcodes can not be boost.
- */
- static const unsigned long twobyte_is_boostable[256 / 32] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ------------------------------- */
- W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
- W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
- W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
- W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
- W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
- W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
- W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
- W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
- W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
- W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
- W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
- W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
- W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
- W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
- W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
- W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
- /* ------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- };
-#undef W
- kprobe_opcode_t opcode;
- kprobe_opcode_t *orig_opcodes = opcodes;
-retry:
- if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
- return 0;
- opcode = *(opcodes++);
-
- /* 2nd-byte opcode */
- if (opcode == 0x0f) {
- if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
- return 0;
- return test_bit(*opcodes, twobyte_is_boostable);
- }
-
- switch (opcode & 0xf0) {
- case 0x60:
- if (0x63 < opcode && opcode < 0x67)
- goto retry; /* prefixes */
- /* can't boost Address-size override and bound */
- return (opcode != 0x62 && opcode != 0x67);
- case 0x70:
- return 0; /* can't boost conditional jump */
- case 0xc0:
- /* can't boost software-interruptions */
- return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
- case 0xd0:
- /* can boost AA* and XLAT */
- return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
- case 0xe0:
- /* can boost in/out and absolute jmps */
- return ((opcode & 0x04) || opcode == 0xea);
- case 0xf0:
- if ((opcode & 0x0c) == 0 && opcode != 0xf1)
- goto retry; /* lock/rep(ne) prefix */
- /* clear and set flags can be boost */
- return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
- default:
- if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
- goto retry; /* prefixes */
- /* can't boost CS override and call */
- return (opcode != 0x2e && opcode != 0x9a);
- }
-}
-
-/*
- * returns non-zero if opcode modifies the interrupt flag.
- */
-static int __kprobes is_IF_modifier(kprobe_opcode_t opcode)
-{
- switch (opcode) {
- case 0xfa: /* cli */
- case 0xfb: /* sti */
- case 0xcf: /* iret/iretd */
- case 0x9d: /* popf/popfd */
- return 1;
- }
- return 0;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- /* insn: must be on special executable page on i386. */
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn)
- return -ENOMEM;
-
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
- p->opcode = *p->addr;
- if (can_boost(p->addr)) {
- p->ainsn.boostable = 0;
- } else {
- p->ainsn.boostable = -1;
- }
- return 0;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, &p->opcode, 1);
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
- mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags;
- kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags;
- kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags
- = (regs->eflags & (TF_MASK | IF_MASK));
- if (is_IF_modifier(p->opcode))
- kcb->kprobe_saved_eflags &= ~IF_MASK;
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- regs->eflags |= TF_MASK;
- regs->eflags &= ~IF_MASK;
- /*single step inline if the instruction is an int3*/
- if (p->opcode == BREAKPOINT_INSTRUCTION)
- regs->eip = (unsigned long)p->addr;
- else
- regs->eip = (unsigned long)p->ainsn.insn;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- unsigned long *sara = (unsigned long *)&regs->esp;
-
- ri->ret_addr = (kprobe_opcode_t *) *sara;
-
- /* Replace the return addr with trampoline addr */
- *sara = (unsigned long) &kretprobe_trampoline;
-}
-
-/*
- * Interrupts are disabled on entry as trap3 is an interrupt gate and they
- * remain disabled thorough out this function.
- */
-static int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- int ret = 0;
- kprobe_opcode_t *addr;
- struct kprobe_ctlblk *kcb;
-
- addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Check we're not actually recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
- regs->eflags &= ~TF_MASK;
- regs->eflags |= kcb->kprobe_saved_eflags;
- goto no_kprobe;
- }
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the handler.
- * We here save the original kprobes variables and
- * just single step on the instruction of the new probe
- * without calling any user handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- regs->eip -= sizeof(kprobe_opcode_t);
- ret = 1;
- goto no_kprobe;
- }
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- * Back up over the (now missing) int3 and run
- * the original instruction.
- */
- regs->eip -= sizeof(kprobe_opcode_t);
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
- goto no_kprobe;
- }
-
- set_current_kprobe(p, regs, kcb);
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
-#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
- if (p->ainsn.boostable == 1 && !p->post_handler){
- /* Boost up -- we can execute copied instructions directly */
- reset_current_kprobe();
- regs->eip = (unsigned long)p->ainsn.insn;
- preempt_enable_no_resched();
- return 1;
- }
-#endif
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/*
- * For function-return probes, init_kprobes() establishes a probepoint
- * here. When a retprobed function returns, this probe is hit and
- * trampoline_probe_handler() runs, calling the kretprobe's handler.
- */
- void __kprobes kretprobe_trampoline_holder(void)
- {
- asm volatile ( ".global kretprobe_trampoline\n"
- "kretprobe_trampoline: \n"
- " pushf\n"
- /* skip cs, eip, orig_eax */
- " subl $12, %esp\n"
- " pushl %fs\n"
- " pushl %ds\n"
- " pushl %es\n"
- " pushl %eax\n"
- " pushl %ebp\n"
- " pushl %edi\n"
- " pushl %esi\n"
- " pushl %edx\n"
- " pushl %ecx\n"
- " pushl %ebx\n"
- " movl %esp, %eax\n"
- " call trampoline_handler\n"
- /* move eflags to cs */
- " movl 52(%esp), %edx\n"
- " movl %edx, 48(%esp)\n"
- /* save true return address on eflags */
- " movl %eax, 52(%esp)\n"
- " popl %ebx\n"
- " popl %ecx\n"
- " popl %edx\n"
- " popl %esi\n"
- " popl %edi\n"
- " popl %ebp\n"
- " popl %eax\n"
- /* skip eip, orig_eax, es, ds, fs */
- " addl $20, %esp\n"
- " popf\n"
- " ret\n");
-}
-
-/*
- * Called from kretprobe_trampoline
- */
-fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
- /* fixup registers */
- regs->xcs = __KERNEL_CS | get_kernel_rpl();
- regs->eip = trampoline_address;
- regs->orig_eax = 0xffffffff;
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler){
- __get_cpu_var(current_kprobe) = &ri->rp->kp;
- get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
- ri->rp->handler(ri, regs);
- __get_cpu_var(current_kprobe) = NULL;
- }
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
- spin_unlock_irqrestore(&kretprobe_lock, flags);
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- return (void*)orig_ret_address;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the "int 3"
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is p->ainsn.insn.
- *
- * This function prepares to return from the post-single-step
- * interrupt. We have to fix up the stack as follows:
- *
- * 0) Except in the case of absolute or indirect jump or call instructions,
- * the new eip is relative to the copied instruction. We need to make
- * it relative to the original instruction.
- *
- * 1) If the single-stepped instruction was pushfl, then the TF and IF
- * flags are set in the just-pushed eflags, and may need to be cleared.
- *
- * 2) If the single-stepped instruction was a call, the return address
- * that is atop the stack is the address following the copied instruction.
- * We need to make it the address following the original instruction.
- *
- * This function also checks instruction size for preparing direct execution.
- */
-static void __kprobes resume_execution(struct kprobe *p,
- struct pt_regs *regs, struct kprobe_ctlblk *kcb)
-{
- unsigned long *tos = (unsigned long *)&regs->esp;
- unsigned long copy_eip = (unsigned long)p->ainsn.insn;
- unsigned long orig_eip = (unsigned long)p->addr;
-
- regs->eflags &= ~TF_MASK;
- switch (p->ainsn.insn[0]) {
- case 0x9c: /* pushfl */
- *tos &= ~(TF_MASK | IF_MASK);
- *tos |= kcb->kprobe_old_eflags;
- break;
- case 0xc2: /* iret/ret/lret */
- case 0xc3:
- case 0xca:
- case 0xcb:
- case 0xcf:
- case 0xea: /* jmp absolute -- eip is correct */
- /* eip is already adjusted, no more changes required */
- p->ainsn.boostable = 1;
- goto no_change;
- case 0xe8: /* call relative - Fix return addr */
- *tos = orig_eip + (*tos - copy_eip);
- break;
- case 0x9a: /* call absolute -- same as call absolute, indirect */
- *tos = orig_eip + (*tos - copy_eip);
- goto no_change;
- case 0xff:
- if ((p->ainsn.insn[1] & 0x30) == 0x10) {
- /*
- * call absolute, indirect
- * Fix return addr; eip is correct.
- * But this is not boostable
- */
- *tos = orig_eip + (*tos - copy_eip);
- goto no_change;
- } else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
- /* eip is correct. And this is boostable */
- p->ainsn.boostable = 1;
- goto no_change;
- }
- default:
- break;
- }
-
- if (p->ainsn.boostable == 0) {
- if ((regs->eip > copy_eip) &&
- (regs->eip - copy_eip) + 5 < MAX_INSN_SIZE) {
- /*
- * These instructions can be executed directly if it
- * jumps back to correct address.
- */
- set_jmp_op((void *)regs->eip,
- (void *)orig_eip + (regs->eip - copy_eip));
- p->ainsn.boostable = 1;
- } else {
- p->ainsn.boostable = -1;
- }
- }
-
- regs->eip = orig_eip + (regs->eip - copy_eip);
-
-no_change:
- return;
-}
-
-/*
- * Interrupts are disabled on entry as trap1 is an interrupt gate and they
- * remain disabled thoroughout this function.
- */
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs, kcb);
- regs->eflags |= kcb->kprobe_saved_eflags;
-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
- if (raw_irqs_disabled_flags(regs->eflags))
- trace_hardirqs_off();
- else
- trace_hardirqs_on();
-#endif
-
- /*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- /*
- * if somebody else is singlestepping across a probe point, eflags
- * will have TF set, in which case, continue the remaining processing
- * of do_debug, as if this is not a probe hit.
- */
- if (regs->eflags & TF_MASK)
- return 0;
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the eip points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->eip = (unsigned long)cur->addr;
- regs->eflags |= kcb->kprobe_old_eflags;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- if (fixup_exception(regs))
- return 1;
-
- /*
- * fixup_exception() could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
- return 0;
-}
-
-/*
- * Wrapper routine to for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode_vm(args->regs))
- return ret;
-
- switch (val) {
- case DIE_INT3:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_DEBUG:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_GPF:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- ret = NOTIFY_STOP;
- preempt_enable();
- break;
- default:
- break;
- }
- return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_esp = &regs->esp;
- addr = (unsigned long)(kcb->jprobe_saved_esp);
-
- /*
- * TBD: As Linus pointed out, gcc assumes that the callee
- * owns the argument space and could overwrite it, e.g.
- * tailcall optimization. So, to be absolutely safe
- * we also save and restore enough stack bytes to cover
- * the argument area.
- */
- memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
- MIN_STACK_SIZE(addr));
- regs->eflags &= ~IF_MASK;
- trace_hardirqs_off();
- regs->eip = (unsigned long)(jp->entry);
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- asm volatile (" xchgl %%ebx,%%esp \n"
- " int3 \n"
- " .globl jprobe_return_end \n"
- " jprobe_return_end: \n"
- " nop \n"::"b"
- (kcb->jprobe_saved_esp):"memory");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- u8 *addr = (u8 *) (regs->eip - 1);
- unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp);
- struct jprobe *jp = container_of(p, struct jprobe, kp);
-
- if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
- if (&regs->esp != kcb->jprobe_saved_esp) {
- struct pt_regs *saved_regs =
- container_of(kcb->jprobe_saved_esp,
- struct pt_regs, esp);
- printk("current esp %p does not match saved esp %p\n",
- &regs->esp, kcb->jprobe_saved_esp);
- printk("Saved registers for jprobe %p\n", jp);
- show_registers(saved_regs);
- printk("Current registers\n");
- show_registers(regs);
- BUG();
- }
- *regs = kcb->jprobe_saved_regs;
- memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- return 0;
-}
-
-int __init arch_init_kprobes(void)
-{
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/x86/kernel/kprobes_64.c
===================================================================
--- linux-2.6-lttng.stable.orig/arch/x86/kernel/kprobes_64.c 2007-10-29 09:51:07.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,761 +0,0 @@
-/*
- * Kernel Probes (KProbes)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) IBM Corporation, 2002, 2004
- *
- * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
- * Probes initial implementation ( includes contributions from
- * Rusty Russell).
- * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
- * interface to access function arguments.
- * 2004-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi
- * <prasanna@in.ibm.com> adapted for x86_64
- * 2005-Mar Roland McGrath <roland@redhat.com>
- * Fixed to handle %rip-relative addressing mode correctly.
- * 2005-May Rusty Lynch <rusty.lynch@intel.com>
- * Added function return probes functionality
- */
-
-#include <linux/kprobes.h>
-#include <linux/ptrace.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/preempt.h>
-#include <linux/module.h>
-#include <linux/kdebug.h>
-
-#include <asm/pgtable.h>
-#include <asm/uaccess.h>
-#include <asm/alternative.h>
-
-void jprobe_return_end(void);
-static void __kprobes arch_copy_kprobe(struct kprobe *p);
-
-DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
-DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-
-struct kretprobe_blackpoint kretprobe_blacklist[] = {
- {"__switch_to", }, /* This function switches only current task, but
- doesn't switch kernel stack.*/
- {NULL, NULL} /* Terminator */
-};
-const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
-
-/*
- * returns non-zero if opcode modifies the interrupt flag.
- */
-static __always_inline int is_IF_modifier(kprobe_opcode_t *insn)
-{
- switch (*insn) {
- case 0xfa: /* cli */
- case 0xfb: /* sti */
- case 0xcf: /* iret/iretd */
- case 0x9d: /* popf/popfd */
- return 1;
- }
-
- if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf)
- return 1;
- return 0;
-}
-
-int __kprobes arch_prepare_kprobe(struct kprobe *p)
-{
- /* insn: must be on special executable page on x86_64. */
- p->ainsn.insn = get_insn_slot();
- if (!p->ainsn.insn) {
- return -ENOMEM;
- }
- arch_copy_kprobe(p);
- return 0;
-}
-
-/*
- * Determine if the instruction uses the %rip-relative addressing mode.
- * If it does, return the address of the 32-bit displacement word.
- * If not, return null.
- */
-static s32 __kprobes *is_riprel(u8 *insn)
-{
-#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
- (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
- (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
- (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
- (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
- << (row % 64))
- static const u64 onebyte_has_modrm[256 / 64] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ------------------------------- */
- W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */
- W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */
- W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */
- W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */
- W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */
- W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */
- W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */
- W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */
- W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */
- W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */
- W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */
- W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */
- W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */
- W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */
- W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */
- W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */
- /* ------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- };
- static const u64 twobyte_has_modrm[256 / 64] = {
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- /* ------------------------------- */
- W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */
- W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */
- W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */
- W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */
- W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */
- W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */
- W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */
- W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */
- W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */
- W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */
- W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */
- W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */
- W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */
- W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */
- W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */
- W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */
- /* ------------------------------- */
- /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
- };
-#undef W
- int need_modrm;
-
- /* Skip legacy instruction prefixes. */
- while (1) {
- switch (*insn) {
- case 0x66:
- case 0x67:
- case 0x2e:
- case 0x3e:
- case 0x26:
- case 0x64:
- case 0x65:
- case 0x36:
- case 0xf0:
- case 0xf3:
- case 0xf2:
- ++insn;
- continue;
- }
- break;
- }
-
- /* Skip REX instruction prefix. */
- if ((*insn & 0xf0) == 0x40)
- ++insn;
-
- if (*insn == 0x0f) { /* Two-byte opcode. */
- ++insn;
- need_modrm = test_bit(*insn, twobyte_has_modrm);
- } else { /* One-byte opcode. */
- need_modrm = test_bit(*insn, onebyte_has_modrm);
- }
-
- if (need_modrm) {
- u8 modrm = *++insn;
- if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
- /* Displacement follows ModRM byte. */
- return (s32 *) ++insn;
- }
- }
-
- /* No %rip-relative addressing mode here. */
- return NULL;
-}
-
-static void __kprobes arch_copy_kprobe(struct kprobe *p)
-{
- s32 *ripdisp;
- memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
- ripdisp = is_riprel(p->ainsn.insn);
- if (ripdisp) {
- /*
- * The copied instruction uses the %rip-relative
- * addressing mode. Adjust the displacement for the
- * difference between the original location of this
- * instruction and the location of the copy that will
- * actually be run. The tricky bit here is making sure
- * that the sign extension happens correctly in this
- * calculation, since we need a signed 32-bit result to
- * be sign-extended to 64 bits when it's added to the
- * %rip value and yield the same 64-bit result that the
- * sign-extension of the original signed 32-bit
- * displacement would have given.
- */
- s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn;
- BUG_ON((s64) (s32) disp != disp); /* Sanity check. */
- *ripdisp = disp;
- }
- p->opcode = *p->addr;
-}
-
-void __kprobes arch_arm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
-}
-
-void __kprobes arch_disarm_kprobe(struct kprobe *p)
-{
- text_poke(p->addr, &p->opcode, 1);
-}
-
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
-}
-
-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- kcb->prev_kprobe.kp = kprobe_running();
- kcb->prev_kprobe.status = kcb->kprobe_status;
- kcb->prev_kprobe.old_rflags = kcb->kprobe_old_rflags;
- kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags;
-}
-
-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
- kcb->kprobe_status = kcb->prev_kprobe.status;
- kcb->kprobe_old_rflags = kcb->prev_kprobe.old_rflags;
- kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags;
-}
-
-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- __get_cpu_var(current_kprobe) = p;
- kcb->kprobe_saved_rflags = kcb->kprobe_old_rflags
- = (regs->eflags & (TF_MASK | IF_MASK));
- if (is_IF_modifier(p->ainsn.insn))
- kcb->kprobe_saved_rflags &= ~IF_MASK;
-}
-
-static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
-{
- regs->eflags |= TF_MASK;
- regs->eflags &= ~IF_MASK;
- /*single step inline if the instruction is an int3*/
- if (p->opcode == BREAKPOINT_INSTRUCTION)
- regs->rip = (unsigned long)p->addr;
- else
- regs->rip = (unsigned long)p->ainsn.insn;
-}
-
-/* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- unsigned long *sara = (unsigned long *)regs->rsp;
-
- ri->ret_addr = (kprobe_opcode_t *) *sara;
- /* Replace the return addr with trampoline addr */
- *sara = (unsigned long) &kretprobe_trampoline;
-}
-
-int __kprobes kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *p;
- int ret = 0;
- kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->rip - sizeof(kprobe_opcode_t));
- struct kprobe_ctlblk *kcb;
-
- /*
- * We don't want to be preempted for the entire
- * duration of kprobe processing
- */
- preempt_disable();
- kcb = get_kprobe_ctlblk();
-
- /* Check we're not actually recursing */
- if (kprobe_running()) {
- p = get_kprobe(addr);
- if (p) {
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
- regs->eflags &= ~TF_MASK;
- regs->eflags |= kcb->kprobe_saved_rflags;
- goto no_kprobe;
- } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
- /* TODO: Provide re-entrancy from
- * post_kprobes_handler() and avoid exception
- * stack corruption while single-stepping on
- * the instruction of the new probe.
- */
- arch_disarm_kprobe(p);
- regs->rip = (unsigned long)p->addr;
- reset_current_kprobe();
- ret = 1;
- } else {
- /* We have reentered the kprobe_handler(), since
- * another probe was hit while within the
- * handler. We here save the original kprobe
- * variables and just single step on instruction
- * of the new probe without calling any user
- * handlers.
- */
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
- return 1;
- }
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /* The breakpoint instruction was removed by
- * another cpu right after we hit, no further
- * handling of this interrupt is appropriate
- */
- regs->rip = (unsigned long)addr;
- ret = 1;
- goto no_kprobe;
- }
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- goto ss_probe;
- }
- }
- goto no_kprobe;
- }
-
- p = get_kprobe(addr);
- if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- * Back up over the (now missing) int3 and run
- * the original instruction.
- */
- regs->rip = (unsigned long)addr;
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
- goto no_kprobe;
- }
-
- set_current_kprobe(p, regs, kcb);
- kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-
- if (p->pre_handler && p->pre_handler(p, regs))
- /* handler has already set things up, so skip ss setup */
- return 1;
-
-ss_probe:
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- return 1;
-
-no_kprobe:
- preempt_enable_no_resched();
- return ret;
-}
-
-/*
- * For function-return probes, init_kprobes() establishes a probepoint
- * here. When a retprobed function returns, this probe is hit and
- * trampoline_probe_handler() runs, calling the kretprobe's handler.
- */
- void kretprobe_trampoline_holder(void)
- {
- asm volatile ( ".global kretprobe_trampoline\n"
- "kretprobe_trampoline: \n"
- "nop\n");
- }
-
-/*
- * Called when we hit the probe point at kretprobe_trampoline
- */
-int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *node, *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
-
- INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because an multiple functions in the call path
- * have a return probe installed on them, and/or more then one return
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always inserted at the head of the list
- * - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
- * real return address, and all the rest will point to
- * kretprobe_trampoline
- */
- hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- if (ri->rp && ri->rp->handler)
- ri->rp->handler(ri, regs);
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
- regs->rip = orig_ret_address;
-
- reset_current_kprobe();
- spin_unlock_irqrestore(&kretprobe_lock, flags);
- preempt_enable_no_resched();
-
- hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
- * to run (and have re-enabled preemption)
- */
- return 1;
-}
-
-/*
- * Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the "int 3"
- * instruction. To avoid the SMP problems that can occur when we
- * temporarily put back the original opcode to single-step, we
- * single-stepped a copy of the instruction. The address of this
- * copy is p->ainsn.insn.
- *
- * This function prepares to return from the post-single-step
- * interrupt. We have to fix up the stack as follows:
- *
- * 0) Except in the case of absolute or indirect jump or call instructions,
- * the new rip is relative to the copied instruction. We need to make
- * it relative to the original instruction.
- *
- * 1) If the single-stepped instruction was pushfl, then the TF and IF
- * flags are set in the just-pushed eflags, and may need to be cleared.
- *
- * 2) If the single-stepped instruction was a call, the return address
- * that is atop the stack is the address following the copied instruction.
- * We need to make it the address following the original instruction.
- */
-static void __kprobes resume_execution(struct kprobe *p,
- struct pt_regs *regs, struct kprobe_ctlblk *kcb)
-{
- unsigned long *tos = (unsigned long *)regs->rsp;
- unsigned long next_rip = 0;
- unsigned long copy_rip = (unsigned long)p->ainsn.insn;
- unsigned long orig_rip = (unsigned long)p->addr;
- kprobe_opcode_t *insn = p->ainsn.insn;
-
- /*skip the REX prefix*/
- if (*insn >= 0x40 && *insn <= 0x4f)
- insn++;
-
- switch (*insn) {
- case 0x9c: /* pushfl */
- *tos &= ~(TF_MASK | IF_MASK);
- *tos |= kcb->kprobe_old_rflags;
- break;
- case 0xc3: /* ret/lret */
- case 0xcb:
- case 0xc2:
- case 0xca:
- regs->eflags &= ~TF_MASK;
- /* rip is already adjusted, no more changes required*/
- return;
- case 0xe8: /* call relative - Fix return addr */
- *tos = orig_rip + (*tos - copy_rip);
- break;
- case 0xff:
- if ((insn[1] & 0x30) == 0x10) {
- /* call absolute, indirect */
- /* Fix return addr; rip is correct. */
- next_rip = regs->rip;
- *tos = orig_rip + (*tos - copy_rip);
- } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
- /* rip is correct. */
- next_rip = regs->rip;
- }
- break;
- case 0xea: /* jmp absolute -- rip is correct */
- next_rip = regs->rip;
- break;
- default:
- break;
- }
-
- regs->eflags &= ~TF_MASK;
- if (next_rip) {
- regs->rip = next_rip;
- } else {
- regs->rip = orig_rip + (regs->rip - copy_rip);
- }
-}
-
-int __kprobes post_kprobe_handler(struct pt_regs *regs)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- if (!cur)
- return 0;
-
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
- cur->post_handler(cur, regs, 0);
- }
-
- resume_execution(cur, regs, kcb);
- regs->eflags |= kcb->kprobe_saved_rflags;
-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
- if (raw_irqs_disabled_flags(regs->eflags))
- trace_hardirqs_off();
- else
- trace_hardirqs_on();
-#endif
-
- /* Restore the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
- restore_previous_kprobe(kcb);
- goto out;
- }
- reset_current_kprobe();
-out:
- preempt_enable_no_resched();
-
- /*
- * if somebody else is singlestepping across a probe point, eflags
- * will have TF set, in which case, continue the remaining processing
- * of do_debug, as if this is not a probe hit.
- */
- if (regs->eflags & TF_MASK)
- return 0;
-
- return 1;
-}
-
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
-{
- struct kprobe *cur = kprobe_running();
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- const struct exception_table_entry *fixup;
-
- switch(kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
- /*
- * We are here because the instruction being single
- * stepped caused a page fault. We reset the current
- * kprobe and the rip points back to the probe address
- * and allow the page fault handler to continue as a
- * normal page fault.
- */
- regs->rip = (unsigned long)cur->addr;
- regs->eflags |= kcb->kprobe_old_rflags;
- if (kcb->kprobe_status == KPROBE_REENTER)
- restore_previous_kprobe(kcb);
- else
- reset_current_kprobe();
- preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
- /*
- * We increment the nmissed count for accounting,
- * we can also use npre/npostfault count for accouting
- * these specific fault cases.
- */
- kprobes_inc_nmissed_count(cur);
-
- /*
- * We come here because instructions in the pre/post
- * handler caused the page_fault, this could happen
- * if handler tries to access user space by
- * copy_from_user(), get_user() etc. Let the
- * user-specified handler try to fix it first.
- */
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- /*
- * In case the user-specified fault handler returned
- * zero, try to fix up.
- */
- fixup = search_exception_tables(regs->rip);
- if (fixup) {
- regs->rip = fixup->fixup;
- return 1;
- }
-
- /*
- * fixup() could not handle it,
- * Let do_page_fault() fix it.
- */
- break;
- default:
- break;
- }
- return 0;
-}
-
-/*
- * Wrapper routine for handling exceptions.
- */
-int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
- unsigned long val, void *data)
-{
- struct die_args *args = (struct die_args *)data;
- int ret = NOTIFY_DONE;
-
- if (args->regs && user_mode(args->regs))
- return ret;
-
- switch (val) {
- case DIE_INT3:
- if (kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_DEBUG:
- if (post_kprobe_handler(args->regs))
- ret = NOTIFY_STOP;
- break;
- case DIE_GPF:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- ret = NOTIFY_STOP;
- preempt_enable();
- break;
- default:
- break;
- }
- return ret;
-}
-
-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_rsp = (long *) regs->rsp;
- addr = (unsigned long)(kcb->jprobe_saved_rsp);
- /*
- * As Linus pointed out, gcc assumes that the callee
- * owns the argument space and could overwrite it, e.g.
- * tailcall optimization. So, to be absolutely safe
- * we also save and restore enough stack bytes to cover
- * the argument area.
- */
- memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
- MIN_STACK_SIZE(addr));
- regs->eflags &= ~IF_MASK;
- trace_hardirqs_off();
- regs->rip = (unsigned long)(jp->entry);
- return 1;
-}
-
-void __kprobes jprobe_return(void)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- asm volatile (" xchg %%rbx,%%rsp \n"
- " int3 \n"
- " .globl jprobe_return_end \n"
- " jprobe_return_end: \n"
- " nop \n"::"b"
- (kcb->jprobe_saved_rsp):"memory");
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- u8 *addr = (u8 *) (regs->rip - 1);
- unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_rsp);
- struct jprobe *jp = container_of(p, struct jprobe, kp);
-
- if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
- if ((long *)regs->rsp != kcb->jprobe_saved_rsp) {
- struct pt_regs *saved_regs =
- container_of(kcb->jprobe_saved_rsp,
- struct pt_regs, rsp);
- printk("current rsp %p does not match saved rsp %p\n",
- (long *)regs->rsp, kcb->jprobe_saved_rsp);
- printk("Saved registers for jprobe %p\n", jp);
- show_registers(saved_regs);
- printk("Current registers\n");
- show_registers(regs);
- BUG();
- }
- *regs = kcb->jprobe_saved_regs;
- memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-
-static struct kprobe trampoline_p = {
- .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
- .pre_handler = trampoline_probe_handler
-};
-
-int __init arch_init_kprobes(void)
-{
- return register_kprobe(&trampoline_p);
-}
-
-int __kprobes arch_trampoline_kprobe(struct kprobe *p)
-{
- if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
- return 1;
-
- return 0;
-}
Index: linux-2.6-lttng.stable/arch/x86/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/arch/x86/instrumentation/Makefile 2007-10-29 09:51:29.000000000 -0400
+++ linux-2.6-lttng.stable/arch/x86/instrumentation/Makefile 2007-10-29 09:51:38.000000000 -0400
@@ -10,3 +10,9 @@ oprofile-y := $(DRIVER_OBJS) init.o b
oprofile-$(CONFIG_X86_LOCAL_APIC) += nmi_int.o op_model_athlon.o \
op_model_ppro.o op_model_p4.o
oprofile-$(CONFIG_X86_IO_APIC) += nmi_timer_int.o
+
+ifeq ($(CONFIG_X86_32),y)
+obj-$(CONFIG_KPROBES) += kprobes_32.o
+else
+obj-$(CONFIG_KPROBES) += kprobes_64.o
+endif
Index: linux-2.6-lttng.stable/arch/x86/kernel/Makefile_32
===================================================================
--- linux-2.6-lttng.stable.orig/arch/x86/kernel/Makefile_32 2007-10-29 09:51:07.000000000 -0400
+++ linux-2.6-lttng.stable/arch/x86/kernel/Makefile_32 2007-10-29 09:51:38.000000000 -0400
@@ -30,7 +30,6 @@ obj-$(CONFIG_KEXEC) += machine_kexec_32
obj-$(CONFIG_CRASH_DUMP) += crash_dump_32.o
obj-$(CONFIG_X86_NUMAQ) += numaq_32.o
obj-$(CONFIG_X86_SUMMIT_NUMA) += summit_32.o
-obj-$(CONFIG_KPROBES) += kprobes_32.o
obj-$(CONFIG_MODULES) += module_32.o
obj-y += sysenter_32.o vsyscall_32.o
obj-$(CONFIG_ACPI_SRAT) += srat_32.o
Index: linux-2.6-lttng.stable/arch/x86/kernel/Makefile_64
===================================================================
--- linux-2.6-lttng.stable.orig/arch/x86/kernel/Makefile_64 2007-10-29 09:51:07.000000000 -0400
+++ linux-2.6-lttng.stable/arch/x86/kernel/Makefile_64 2007-10-29 09:51:38.000000000 -0400
@@ -28,7 +28,6 @@ obj-$(CONFIG_EARLY_PRINTK) += early_prin
obj-$(CONFIG_IOMMU) += pci-gart_64.o aperture_64.o
obj-$(CONFIG_CALGARY_IOMMU) += pci-calgary_64.o tce_64.o
obj-$(CONFIG_SWIOTLB) += pci-swiotlb_64.o
-obj-$(CONFIG_KPROBES) += kprobes_64.o
obj-$(CONFIG_X86_PM_TIMER) += pmtimer_64.o
obj-$(CONFIG_X86_VSMP) += vsmp_64.o
obj-$(CONFIG_K8_NB) += k8.o
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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