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Subject[tip:perf/uprobes] uprobes/core: Clean up, refactor and improve the code
Commit-ID:  7b2d81d48a2d8e37efb6ce7b4d5ef58822b30d89
Gitweb: http://git.kernel.org/tip/7b2d81d48a2d8e37efb6ce7b4d5ef58822b30d89
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Fri, 17 Feb 2012 09:27:41 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 17 Feb 2012 10:18:07 +0100

uprobes/core: Clean up, refactor and improve the code

Make the uprobes code readable to me:

- improve the Kconfig text so that a mere mortal gets some idea
what CONFIG_UPROBES=y is really about

- do trivial renames to standardize around the uprobes_*() namespace

- clean up and simplify various code flow details

- separate basic blocks of functionality

- line break artifact and white space related removal

- use standard local varible definition blocks

- use vertical spacing to make things more readable

- remove unnecessary volatile

- restructure comment blocks to make them more uniform and
more readable in general

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/Kconfig | 14 ++-
arch/x86/include/asm/uprobes.h | 17 ++--
arch/x86/kernel/uprobes.c | 129 ++++++++++++-----------
include/linux/uprobes.h | 28 +++---
kernel/uprobes.c | 219 +++++++++++++++++++++++-----------------
mm/mmap.c | 12 +-
6 files changed, 233 insertions(+), 186 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 284f589..cca5b54 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -66,13 +66,19 @@ config OPTPROBES
depends on !PREEMPT

config UPROBES
- bool "User-space probes (EXPERIMENTAL)"
+ bool "Transparent user-space probes (EXPERIMENTAL)"
depends on ARCH_SUPPORTS_UPROBES
default n
help
- Uprobes enables kernel subsystems to establish probepoints
- in user applications and execute handler functions when
- the probepoints are hit.
+ Uprobes is the user-space counterpart to kprobes: they
+ enable instrumentation applications (such as 'perf probe')
+ to establish unintrusive probes in user-space binaries and
+ libraries, by executing handler functions when the probes
+ are hit by user-space applications.
+
+ ( These probes come in the form of single-byte breakpoints,
+ managed by the kernel and kept transparent to the probed
+ application. )

If in doubt, say "N".

diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 8208234..072df39 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -1,7 +1,7 @@
#ifndef _ASM_UPROBES_H
#define _ASM_UPROBES_H
/*
- * Userspace Probes (UProbes) for x86
+ * User-space Probes (UProbes) for x86
*
* 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
@@ -24,19 +24,20 @@
*/

typedef u8 uprobe_opcode_t;
-#define MAX_UINSN_BYTES 16
-#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */

-#define UPROBES_BKPT_INSN 0xcc
-#define UPROBES_BKPT_INSN_SIZE 1
+#define MAX_UINSN_BYTES 16
+#define UPROBES_XOL_SLOT_BYTES 128 /* to keep it cache aligned */
+
+#define UPROBES_BKPT_INSN 0xcc
+#define UPROBES_BKPT_INSN_SIZE 1

struct uprobe_arch_info {
- u16 fixups;
+ u16 fixups;
#ifdef CONFIG_X86_64
- unsigned long rip_rela_target_address;
+ unsigned long rip_rela_target_address;
#endif
};

struct uprobe;
-extern int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
+extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
#endif /* _ASM_UPROBES_H */
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 2a301bb..cf2a184 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -1,5 +1,5 @@
/*
- * Userspace Probes (UProbes) for x86
+ * User-space Probes (UProbes) for x86
*
* 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
@@ -20,7 +20,6 @@
* Srikar Dronamraju
* Jim Keniston
*/
-
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
@@ -42,10 +41,10 @@
#define UPROBES_FIX_RIP_CX 0x4000

/* Adaptations for mhiramat x86 decoder v14. */
-#define OPCODE1(insn) ((insn)->opcode.bytes[0])
-#define OPCODE2(insn) ((insn)->opcode.bytes[1])
-#define OPCODE3(insn) ((insn)->opcode.bytes[2])
-#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)
+#define OPCODE1(insn) ((insn)->opcode.bytes[0])
+#define OPCODE2(insn) ((insn)->opcode.bytes[1])
+#define OPCODE3(insn) ((insn)->opcode.bytes[2])
+#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)

#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) | \
@@ -55,7 +54,7 @@
<< (row % 32))

#ifdef CONFIG_X86_64
-static volatile u32 good_insns_64[256 / 32] = {
+static u32 good_insns_64[256 / 32] = {
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/* ---------------------------------------------- */
W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */
@@ -81,7 +80,7 @@ static volatile u32 good_insns_64[256 / 32] = {

/* Good-instruction tables for 32-bit apps */

-static volatile u32 good_insns_32[256 / 32] = {
+static u32 good_insns_32[256 / 32] = {
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/* ---------------------------------------------- */
W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 00 */
@@ -105,7 +104,7 @@ static volatile u32 good_insns_32[256 / 32] = {
};

/* Using this for both 64-bit and 32-bit apps */
-static volatile u32 good_2byte_insns[256 / 32] = {
+static u32 good_2byte_insns[256 / 32] = {
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/* ---------------------------------------------- */
W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */
@@ -132,42 +131,47 @@ static volatile u32 good_2byte_insns[256 / 32] = {

/*
* opcodes we'll probably never support:
- * 6c-6d, e4-e5, ec-ed - in
- * 6e-6f, e6-e7, ee-ef - out
- * cc, cd - int3, int
- * cf - iret
- * d6 - illegal instruction
- * f1 - int1/icebp
- * f4 - hlt
- * fa, fb - cli, sti
- * 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2
+ *
+ * 6c-6d, e4-e5, ec-ed - in
+ * 6e-6f, e6-e7, ee-ef - out
+ * cc, cd - int3, int
+ * cf - iret
+ * d6 - illegal instruction
+ * f1 - int1/icebp
+ * f4 - hlt
+ * fa, fb - cli, sti
+ * 0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2
*
* invalid opcodes in 64-bit mode:
- * 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5
*
- * 63 - we support this opcode in x86_64 but not in i386.
+ * 06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5
+ * 63 - we support this opcode in x86_64 but not in i386.
*
* opcodes we may need to refine support for:
- * 0f - 2-byte instructions: For many of these instructions, the validity
- * depends on the prefix and/or the reg field. On such instructions, we
- * just consider the opcode combination valid if it corresponds to any
- * valid instruction.
- * 8f - Group 1 - only reg = 0 is OK
- * c6-c7 - Group 11 - only reg = 0 is OK
- * d9-df - fpu insns with some illegal encodings
- * f2, f3 - repnz, repz prefixes. These are also the first byte for
- * certain floating-point instructions, such as addsd.
- * fe - Group 4 - only reg = 0 or 1 is OK
- * ff - Group 5 - only reg = 0-6 is OK
+ *
+ * 0f - 2-byte instructions: For many of these instructions, the validity
+ * depends on the prefix and/or the reg field. On such instructions, we
+ * just consider the opcode combination valid if it corresponds to any
+ * valid instruction.
+ *
+ * 8f - Group 1 - only reg = 0 is OK
+ * c6-c7 - Group 11 - only reg = 0 is OK
+ * d9-df - fpu insns with some illegal encodings
+ * f2, f3 - repnz, repz prefixes. These are also the first byte for
+ * certain floating-point instructions, such as addsd.
+ *
+ * fe - Group 4 - only reg = 0 or 1 is OK
+ * ff - Group 5 - only reg = 0-6 is OK
*
* others -- Do we need to support these?
- * 0f - (floating-point?) prefetch instructions
- * 07, 17, 1f - pop es, pop ss, pop ds
- * 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes --
+ *
+ * 0f - (floating-point?) prefetch instructions
+ * 07, 17, 1f - pop es, pop ss, pop ds
+ * 26, 2e, 36, 3e - es:, cs:, ss:, ds: segment prefixes --
* but 64 and 65 (fs: and gs:) seem to be used, so we support them
- * 67 - addr16 prefix
- * ce - into
- * f0 - lock prefix
+ * 67 - addr16 prefix
+ * ce - into
+ * f0 - lock prefix
*/

/*
@@ -182,11 +186,11 @@ static bool is_prefix_bad(struct insn *insn)

for (i = 0; i < insn->prefixes.nbytes; i++) {
switch (insn->prefixes.bytes[i]) {
- case 0x26: /*INAT_PFX_ES */
- case 0x2E: /*INAT_PFX_CS */
- case 0x36: /*INAT_PFX_DS */
- case 0x3E: /*INAT_PFX_SS */
- case 0xF0: /*INAT_PFX_LOCK */
+ case 0x26: /* INAT_PFX_ES */
+ case 0x2E: /* INAT_PFX_CS */
+ case 0x36: /* INAT_PFX_DS */
+ case 0x3E: /* INAT_PFX_SS */
+ case 0xF0: /* INAT_PFX_LOCK */
return true;
}
}
@@ -201,12 +205,15 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)
insn_get_opcode(insn);
if (is_prefix_bad(insn))
return -ENOTSUPP;
+
if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_32))
return 0;
+
if (insn->opcode.nbytes == 2) {
if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns))
return 0;
}
+
return -ENOTSUPP;
}

@@ -282,12 +289,12 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
* disastrous.
*
* Some useful facts about rip-relative instructions:
- * - There's always a modrm byte.
- * - There's never a SIB byte.
- * - The displacement is always 4 bytes.
+ *
+ * - There's always a modrm byte.
+ * - There's never a SIB byte.
+ * - The displacement is always 4 bytes.
*/
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
- struct insn *insn)
+static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
{
u8 *cursor;
u8 reg;
@@ -342,13 +349,12 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
}

/* Target address = address of next instruction + (signed) offset */
- uprobe->arch_info.rip_rela_target_address = (long)insn->length
- + insn->displacement.value;
+ uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value;
+
/* Displacement field is gone; slide immediate field (if any) over. */
if (insn->immediate.nbytes) {
cursor++;
- memmove(cursor, cursor + insn->displacement.nbytes,
- insn->immediate.nbytes);
+ memmove(cursor, cursor + insn->displacement.nbytes, insn->immediate.nbytes);
}
return;
}
@@ -361,8 +367,10 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
insn_get_opcode(insn);
if (is_prefix_bad(insn))
return -ENOTSUPP;
+
if (test_bit(OPCODE1(insn), (unsigned long *)good_insns_64))
return 0;
+
if (insn->opcode.nbytes == 2) {
if (test_bit(OPCODE2(insn), (unsigned long *)good_2byte_insns))
return 0;
@@ -370,34 +378,31 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
return -ENOTSUPP;
}

-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe,
- struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
{
if (mm->context.ia32_compat)
return validate_insn_32bits(uprobe, insn);
return validate_insn_64bits(uprobe, insn);
}
-#else
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe,
- struct insn *insn)
+#else /* 32-bit: */
+static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
{
- return;
+ /* No RIP-relative addressing on 32-bit */
}

-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe,
- struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
{
return validate_insn_32bits(uprobe, insn);
}
#endif /* CONFIG_X86_64 */

/**
- * analyze_insn - instruction analysis including validity and fixups.
+ * arch_uprobes_analyze_insn - instruction analysis including validity and fixups.
* @mm: the probed address space.
* @uprobe: the probepoint information.
* Return 0 on success or a -ve number on error.
*/
-int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
+int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
{
int ret;
struct insn insn;
@@ -406,7 +411,9 @@ int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
ret = validate_insn_bits(mm, uprobe, &insn);
if (ret != 0)
return ret;
+
handle_riprel_insn(mm, uprobe, &insn);
prepare_fixups(uprobe, &insn);
+
return 0;
}
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index f1d13fd..64e45f1 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_UPROBES_H
#define _LINUX_UPROBES_H
/*
- * Userspace Probes (UProbes)
+ * User-space Probes (UProbes)
*
* 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
@@ -40,8 +40,10 @@ struct uprobe_arch_info {};
#define uprobe_opcode_sz sizeof(uprobe_opcode_t)

/* flags that denote/change uprobes behaviour */
+
/* Have a copy of original instruction */
#define UPROBES_COPY_INSN 0x1
+
/* Dont run handlers when first register/ last unregister in progress*/
#define UPROBES_RUN_HANDLER 0x2

@@ -70,27 +72,23 @@ struct uprobe {
};

#ifdef CONFIG_UPROBES
-extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe,
- unsigned long vaddr);
-extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe,
- unsigned long vaddr, bool verify);
+extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr);
+extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify);
extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn);
-extern int register_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer);
-extern void unregister_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer);
-extern int mmap_uprobe(struct vm_area_struct *vma);
+extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
+extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
+extern int uprobe_mmap(struct vm_area_struct *vma);
#else /* CONFIG_UPROBES is not defined */
-static inline int register_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer)
+static inline int
+uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
{
return -ENOSYS;
}
-static inline void unregister_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer)
+static inline void
+uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
{
}
-static inline int mmap_uprobe(struct vm_area_struct *vma)
+static inline int uprobe_mmap(struct vm_area_struct *vma)
{
return 0;
}
diff --git a/kernel/uprobes.c b/kernel/uprobes.c
index 72e8bb3..884817f 100644
--- a/kernel/uprobes.c
+++ b/kernel/uprobes.c
@@ -1,5 +1,5 @@
/*
- * Userspace Probes (UProbes)
+ * User-space Probes (UProbes)
*
* 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
@@ -29,24 +29,26 @@
#include <linux/rmap.h> /* anon_vma_prepare */
#include <linux/mmu_notifier.h> /* set_pte_at_notify */
#include <linux/swap.h> /* try_to_free_swap */
+
#include <linux/uprobes.h>

static struct rb_root uprobes_tree = RB_ROOT;
+
static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */

#define UPROBES_HASH_SZ 13
+
/* serialize (un)register */
static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
-#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) %\
- UPROBES_HASH_SZ])
+
+#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])

/* serialize uprobe->pending_list */
static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
-#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) %\
- UPROBES_HASH_SZ])
+#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])

/*
- * uprobe_events allows us to skip the mmap_uprobe if there are no uprobe
+ * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe
* events active at this time. Probably a fine grained per inode count is
* better?
*/
@@ -58,9 +60,9 @@ static atomic_t uprobe_events = ATOMIC_INIT(0);
* vm_area_struct wasnt recommended.
*/
struct vma_info {
- struct list_head probe_list;
- struct mm_struct *mm;
- loff_t vaddr;
+ struct list_head probe_list;
+ struct mm_struct *mm;
+ loff_t vaddr;
};

/*
@@ -79,8 +81,7 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
if (!is_register)
return true;

- if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) ==
- (VM_READ|VM_EXEC))
+ if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC))
return true;

return false;
@@ -92,6 +93,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)

vaddr = vma->vm_start + offset;
vaddr -= vma->vm_pgoff << PAGE_SHIFT;
+
return vaddr;
}

@@ -105,8 +107,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
*
* Returns 0 on success, -EFAULT on failure.
*/
-static int __replace_page(struct vm_area_struct *vma, struct page *page,
- struct page *kpage)
+static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage)
{
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
@@ -163,7 +164,7 @@ out:
*/
bool __weak is_bkpt_insn(uprobe_opcode_t *insn)
{
- return (*insn == UPROBES_BKPT_INSN);
+ return *insn == UPROBES_BKPT_INSN;
}

/*
@@ -203,6 +204,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma);
if (ret <= 0)
return ret;
+
ret = -EINVAL;

/*
@@ -239,6 +241,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
vaddr_new = kmap_atomic(new_page);

memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
+
/* poke the new insn in, ASSUMES we don't cross page boundary */
vaddr &= ~PAGE_MASK;
BUG_ON(vaddr + uprobe_opcode_sz > PAGE_SIZE);
@@ -260,7 +263,8 @@ unlock_out:
page_cache_release(new_page);

put_out:
- put_page(old_page); /* we did a get_page in the beginning */
+ put_page(old_page);
+
return ret;
}

@@ -276,8 +280,7 @@ put_out:
* For mm @mm, read the opcode at @vaddr and store it in @opcode.
* Return 0 (success) or a negative errno.
*/
-static int read_opcode(struct mm_struct *mm, unsigned long vaddr,
- uprobe_opcode_t *opcode)
+static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode)
{
struct page *page;
void *vaddr_new;
@@ -293,15 +296,18 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr,
memcpy(opcode, vaddr_new + vaddr, uprobe_opcode_sz);
kunmap_atomic(vaddr_new);
unlock_page(page);
- put_page(page); /* we did a get_user_pages in the beginning */
+
+ put_page(page);
+
return 0;
}

static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr)
{
uprobe_opcode_t opcode;
- int result = read_opcode(mm, vaddr, &opcode);
+ int result;

+ result = read_opcode(mm, vaddr, &opcode);
if (result)
return result;

@@ -320,11 +326,11 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr)
* For mm @mm, store the breakpoint instruction at @vaddr.
* Return 0 (success) or a negative errno.
*/
-int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe,
- unsigned long vaddr)
+int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr)
{
- int result = is_bkpt_at_addr(mm, vaddr);
+ int result;

+ result = is_bkpt_at_addr(mm, vaddr);
if (result == 1)
return -EEXIST;

@@ -344,35 +350,35 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe,
* For mm @mm, restore the original opcode (opcode) at @vaddr.
* Return 0 (success) or a negative errno.
*/
-int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe,
- unsigned long vaddr, bool verify)
+int __weak
+set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify)
{
if (verify) {
- int result = is_bkpt_at_addr(mm, vaddr);
+ int result;

+ result = is_bkpt_at_addr(mm, vaddr);
if (!result)
return -EINVAL;

if (result != 1)
return result;
}
- return write_opcode(mm, uprobe, vaddr,
- *(uprobe_opcode_t *)uprobe->insn);
+ return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn);
}

static int match_uprobe(struct uprobe *l, struct uprobe *r)
{
if (l->inode < r->inode)
return -1;
+
if (l->inode > r->inode)
return 1;
- else {
- if (l->offset < r->offset)
- return -1;

- if (l->offset > r->offset)
- return 1;
- }
+ if (l->offset < r->offset)
+ return -1;
+
+ if (l->offset > r->offset)
+ return 1;

return 0;
}
@@ -391,6 +397,7 @@ static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset)
atomic_inc(&uprobe->ref);
return uprobe;
}
+
if (match < 0)
n = n->rb_left;
else
@@ -411,6 +418,7 @@ static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
spin_lock_irqsave(&uprobes_treelock, flags);
uprobe = __find_uprobe(inode, offset);
spin_unlock_irqrestore(&uprobes_treelock, flags);
+
return uprobe;
}

@@ -436,16 +444,18 @@ static struct uprobe *__insert_uprobe(struct uprobe *uprobe)
p = &parent->rb_right;

}
+
u = NULL;
rb_link_node(&uprobe->rb_node, parent, p);
rb_insert_color(&uprobe->rb_node, &uprobes_tree);
/* get access + creation ref */
atomic_set(&uprobe->ref, 2);
+
return u;
}

/*
- * Acquires uprobes_treelock.
+ * Acquire uprobes_treelock.
* Matching uprobe already exists in rbtree;
* increment (access refcount) and return the matching uprobe.
*
@@ -460,6 +470,7 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
spin_lock_irqsave(&uprobes_treelock, flags);
u = __insert_uprobe(uprobe);
spin_unlock_irqrestore(&uprobes_treelock, flags);
+
return u;
}

@@ -490,19 +501,22 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
kfree(uprobe);
uprobe = cur_uprobe;
iput(inode);
- } else
+ } else {
atomic_inc(&uprobe_events);
+ }
+
return uprobe;
}

/* Returns the previous consumer */
-static struct uprobe_consumer *add_consumer(struct uprobe *uprobe,
- struct uprobe_consumer *consumer)
+static struct uprobe_consumer *
+consumer_add(struct uprobe *uprobe, struct uprobe_consumer *consumer)
{
down_write(&uprobe->consumer_rwsem);
consumer->next = uprobe->consumers;
uprobe->consumers = consumer;
up_write(&uprobe->consumer_rwsem);
+
return consumer->next;
}

@@ -511,8 +525,7 @@ static struct uprobe_consumer *add_consumer(struct uprobe *uprobe,
* Return true if the @consumer is deleted successfully
* or return false.
*/
-static bool del_consumer(struct uprobe *uprobe,
- struct uprobe_consumer *consumer)
+static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer)
{
struct uprobe_consumer **con;
bool ret = false;
@@ -526,6 +539,7 @@ static bool del_consumer(struct uprobe *uprobe,
}
}
up_write(&uprobe->consumer_rwsem);
+
return ret;
}

@@ -557,15 +571,15 @@ static int __copy_insn(struct address_space *mapping,
memcpy(insn, vaddr + off1, nbytes);
kunmap_atomic(vaddr);
page_cache_release(page);
+
return 0;
}

-static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma,
- unsigned long addr)
+static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
{
struct address_space *mapping;
- int bytes;
unsigned long nbytes;
+ int bytes;

addr &= ~PAGE_MASK;
nbytes = PAGE_SIZE - addr;
@@ -605,6 +619,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
return -EEXIST;

addr = (unsigned long)vaddr;
+
if (!(uprobe->flags & UPROBES_COPY_INSN)) {
ret = copy_insn(uprobe, vma, addr);
if (ret)
@@ -613,7 +628,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn))
return -EEXIST;

- ret = analyze_insn(mm, uprobe);
+ ret = arch_uprobes_analyze_insn(mm, uprobe);
if (ret)
return ret;

@@ -624,8 +639,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
return ret;
}

-static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
- loff_t vaddr)
+static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr)
{
set_orig_insn(mm, uprobe, (unsigned long)vaddr, true);
}
@@ -649,9 +663,11 @@ static struct vma_info *__find_next_vma_info(struct list_head *head,
struct prio_tree_iter iter;
struct vm_area_struct *vma;
struct vma_info *tmpvi;
- loff_t vaddr;
- unsigned long pgoff = offset >> PAGE_SHIFT;
+ unsigned long pgoff;
int existing_vma;
+ loff_t vaddr;
+
+ pgoff = offset >> PAGE_SHIFT;

vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
@@ -659,6 +675,7 @@ static struct vma_info *__find_next_vma_info(struct list_head *head,

existing_vma = 0;
vaddr = vma_address(vma, offset);
+
list_for_each_entry(tmpvi, head, probe_list) {
if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) {
existing_vma = 1;
@@ -670,14 +687,15 @@ static struct vma_info *__find_next_vma_info(struct list_head *head,
* Another vma needs a probe to be installed. However skip
* installing the probe if the vma is about to be unlinked.
*/
- if (!existing_vma &&
- atomic_inc_not_zero(&vma->vm_mm->mm_users)) {
+ if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) {
vi->mm = vma->vm_mm;
vi->vaddr = vaddr;
list_add(&vi->probe_list, head);
+
return vi;
}
}
+
return NULL;
}

@@ -685,11 +703,12 @@ static struct vma_info *__find_next_vma_info(struct list_head *head,
* Iterate in the rmap prio tree and find a vma where a probe has not
* yet been inserted.
*/
-static struct vma_info *find_next_vma_info(struct list_head *head,
- loff_t offset, struct address_space *mapping,
- bool is_register)
+static struct vma_info *
+find_next_vma_info(struct list_head *head, loff_t offset, struct address_space *mapping,
+ bool is_register)
{
struct vma_info *vi, *retvi;
+
vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL);
if (!vi)
return ERR_PTR(-ENOMEM);
@@ -700,6 +719,7 @@ static struct vma_info *find_next_vma_info(struct list_head *head,

if (!retvi)
kfree(vi);
+
return retvi;
}

@@ -711,16 +731,23 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
struct vma_info *vi, *tmpvi;
struct mm_struct *mm;
loff_t vaddr;
- int ret = 0;
+ int ret;

mapping = uprobe->inode->i_mapping;
INIT_LIST_HEAD(&try_list);
- while ((vi = find_next_vma_info(&try_list, uprobe->offset,
- mapping, is_register)) != NULL) {
+
+ ret = 0;
+
+ for (;;) {
+ vi = find_next_vma_info(&try_list, uprobe->offset, mapping, is_register);
+ if (!vi)
+ break;
+
if (IS_ERR(vi)) {
ret = PTR_ERR(vi);
break;
}
+
mm = vi->mm;
down_read(&mm->mmap_sem);
vma = find_vma(mm, (unsigned long)vi->vaddr);
@@ -755,19 +782,21 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
break;
}
}
+
list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
list_del(&vi->probe_list);
kfree(vi);
}
+
return ret;
}

-static int __register_uprobe(struct uprobe *uprobe)
+static int __uprobe_register(struct uprobe *uprobe)
{
return register_for_each_vma(uprobe, true);
}

-static void __unregister_uprobe(struct uprobe *uprobe)
+static void __uprobe_unregister(struct uprobe *uprobe)
{
if (!register_for_each_vma(uprobe, false))
delete_uprobe(uprobe);
@@ -776,15 +805,15 @@ static void __unregister_uprobe(struct uprobe *uprobe)
}

/*
- * register_uprobe - register a probe
+ * uprobe_register - register a probe
* @inode: the file in which the probe has to be placed.
* @offset: offset from the start of the file.
* @consumer: information on howto handle the probe..
*
- * Apart from the access refcount, register_uprobe() takes a creation
+ * Apart from the access refcount, uprobe_register() takes a creation
* refcount (thro alloc_uprobe) if and only if this @uprobe is getting
* inserted into the rbtree (i.e first consumer for a @inode:@offset
- * tuple). Creation refcount stops unregister_uprobe from freeing the
+ * tuple). Creation refcount stops uprobe_unregister from freeing the
* @uprobe even before the register operation is complete. Creation
* refcount is released when the last @consumer for the @uprobe
* unregisters.
@@ -792,28 +821,29 @@ static void __unregister_uprobe(struct uprobe *uprobe)
* Return errno if it cannot successully install probes
* else return 0 (success)
*/
-int register_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer)
+int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
{
struct uprobe *uprobe;
- int ret = -EINVAL;
+ int ret;

if (!inode || !consumer || consumer->next)
- return ret;
+ return -EINVAL;

if (offset > i_size_read(inode))
- return ret;
+ return -EINVAL;

ret = 0;
mutex_lock(uprobes_hash(inode));
uprobe = alloc_uprobe(inode, offset);
- if (uprobe && !add_consumer(uprobe, consumer)) {
- ret = __register_uprobe(uprobe);
+
+ if (uprobe && !consumer_add(uprobe, consumer)) {
+ ret = __uprobe_register(uprobe);
if (ret) {
uprobe->consumers = NULL;
- __unregister_uprobe(uprobe);
- } else
+ __uprobe_unregister(uprobe);
+ } else {
uprobe->flags |= UPROBES_RUN_HANDLER;
+ }
}

mutex_unlock(uprobes_hash(inode));
@@ -823,15 +853,14 @@ int register_uprobe(struct inode *inode, loff_t offset,
}

/*
- * unregister_uprobe - unregister a already registered probe.
+ * uprobe_unregister - unregister a already registered probe.
* @inode: the file in which the probe has to be removed.
* @offset: offset from the start of the file.
* @consumer: identify which probe if multiple probes are colocated.
*/
-void unregister_uprobe(struct inode *inode, loff_t offset,
- struct uprobe_consumer *consumer)
+void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer)
{
- struct uprobe *uprobe = NULL;
+ struct uprobe *uprobe;

if (!inode || !consumer)
return;
@@ -841,15 +870,14 @@ void unregister_uprobe(struct inode *inode, loff_t offset,
return;

mutex_lock(uprobes_hash(inode));
- if (!del_consumer(uprobe, consumer))
- goto unreg_out;

- if (!uprobe->consumers) {
- __unregister_uprobe(uprobe);
- uprobe->flags &= ~UPROBES_RUN_HANDLER;
+ if (consumer_del(uprobe, consumer)) {
+ if (!uprobe->consumers) {
+ __uprobe_unregister(uprobe);
+ uprobe->flags &= ~UPROBES_RUN_HANDLER;
+ }
}

-unreg_out:
mutex_unlock(uprobes_hash(inode));
if (uprobe)
put_uprobe(uprobe);
@@ -870,6 +898,7 @@ static struct rb_node *find_least_offset_node(struct inode *inode)
while (n) {
uprobe = rb_entry(n, struct uprobe, rb_node);
match = match_uprobe(&u, uprobe);
+
if (uprobe->inode == inode)
close_node = n;

@@ -881,6 +910,7 @@ static struct rb_node *find_least_offset_node(struct inode *inode)
else
n = n->rb_right;
}
+
return close_node;
}

@@ -890,11 +920,13 @@ static struct rb_node *find_least_offset_node(struct inode *inode)
static void build_probe_list(struct inode *inode, struct list_head *head)
{
struct uprobe *uprobe;
- struct rb_node *n;
unsigned long flags;
+ struct rb_node *n;

spin_lock_irqsave(&uprobes_treelock, flags);
+
n = find_least_offset_node(inode);
+
for (; n; n = rb_next(n)) {
uprobe = rb_entry(n, struct uprobe, rb_node);
if (uprobe->inode != inode)
@@ -903,6 +935,7 @@ static void build_probe_list(struct inode *inode, struct list_head *head)
list_add(&uprobe->pending_list, head);
atomic_inc(&uprobe->ref);
}
+
spin_unlock_irqrestore(&uprobes_treelock, flags);
}

@@ -912,42 +945,44 @@ static void build_probe_list(struct inode *inode, struct list_head *head)
*
* Return -ve no if we fail to insert probes and we cannot
* bail-out.
- * Return 0 otherwise. i.e :
+ * Return 0 otherwise. i.e:
+ *
* - successful insertion of probes
* - (or) no possible probes to be inserted.
* - (or) insertion of probes failed but we can bail-out.
*/
-int mmap_uprobe(struct vm_area_struct *vma)
+int uprobe_mmap(struct vm_area_struct *vma)
{
struct list_head tmp_list;
struct uprobe *uprobe, *u;
struct inode *inode;
- int ret = 0;
+ int ret;

if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
- return ret; /* Bail-out */
+ return 0;

inode = vma->vm_file->f_mapping->host;
if (!inode)
- return ret;
+ return 0;

INIT_LIST_HEAD(&tmp_list);
mutex_lock(uprobes_mmap_hash(inode));
build_probe_list(inode, &tmp_list);
+
+ ret = 0;
+
list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
loff_t vaddr;

list_del(&uprobe->pending_list);
if (!ret) {
vaddr = vma_address(vma, uprobe->offset);
- if (vaddr < vma->vm_start || vaddr >= vma->vm_end) {
- put_uprobe(uprobe);
- continue;
+ if (vaddr >= vma->vm_start && vaddr < vma->vm_end) {
+ ret = install_breakpoint(vma->vm_mm, uprobe, vma, vaddr);
+ /* Ignore double add: */
+ if (ret == -EEXIST)
+ ret = 0;
}
- ret = install_breakpoint(vma->vm_mm, uprobe, vma,
- vaddr);
- if (ret == -EEXIST)
- ret = 0;
}
put_uprobe(uprobe);
}
diff --git a/mm/mmap.c b/mm/mmap.c
index 1aed183..5a863d3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -618,10 +618,10 @@ again: remove_next = 1 + (end > next->vm_end);
mutex_unlock(&mapping->i_mmap_mutex);

if (root) {
- mmap_uprobe(vma);
+ uprobe_mmap(vma);

if (adjust_next)
- mmap_uprobe(next);
+ uprobe_mmap(next);
}

if (remove_next) {
@@ -646,7 +646,7 @@ again: remove_next = 1 + (end > next->vm_end);
}
}
if (insert && file)
- mmap_uprobe(insert);
+ uprobe_mmap(insert);

validate_mm(mm);

@@ -1340,7 +1340,7 @@ out:
} else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
make_pages_present(addr, addr + len);

- if (file && mmap_uprobe(vma))
+ if (file && uprobe_mmap(vma))
/* matching probes but cannot insert */
goto unmap_and_free_vma;

@@ -2301,7 +2301,7 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
security_vm_enough_memory_mm(mm, vma_pages(vma)))
return -ENOMEM;

- if (vma->vm_file && mmap_uprobe(vma))
+ if (vma->vm_file && uprobe_mmap(vma))
return -EINVAL;

vma_link(mm, vma, prev, rb_link, rb_parent);
@@ -2374,7 +2374,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
if (new_vma->vm_file) {
get_file(new_vma->vm_file);

- if (mmap_uprobe(new_vma))
+ if (uprobe_mmap(new_vma))
goto out_free_mempol;

if (vma->vm_flags & VM_EXECUTABLE)

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