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Subject[PATCH 4/4] FRV: utrace: Implement tracehooks
Date
Implement the tracehooks stuff for ptrace on FRV.

Signed-off-by: David Howells <dhowells@redhat.com>
---
arch/frv/Kconfig | 1
arch/frv/include/asm/elf.h | 1
arch/frv/include/asm/ptrace.h | 11 +
arch/frv/include/asm/syscall.h | 123 +++++++++++++
arch/frv/kernel/entry.S | 12 +
arch/frv/kernel/ptrace.c | 378 +++++++++++++++++++++++-----------------
arch/frv/kernel/signal.c | 5 +
7 files changed, 367 insertions(+), 164 deletions(-)
create mode 100644 arch/frv/include/asm/syscall.h

diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 9d1552a..8a5bd7a 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -6,6 +6,7 @@ config FRV
bool
default y
select HAVE_IDE
+ select HAVE_ARCH_TRACEHOOK

config ZONE_DMA
bool
diff --git a/arch/frv/include/asm/elf.h b/arch/frv/include/asm/elf.h
index 7279ec0..7bbf6e4 100644
--- a/arch/frv/include/asm/elf.h
+++ b/arch/frv/include/asm/elf.h
@@ -116,6 +116,7 @@ do { \
} while(0)

#define USE_ELF_CORE_DUMP
+#define CORE_DUMP_USE_REGSET
#define ELF_FDPIC_CORE_EFLAGS EF_FRV_FDPIC
#define ELF_EXEC_PAGESIZE 16384

diff --git a/arch/frv/include/asm/ptrace.h b/arch/frv/include/asm/ptrace.h
index cf69340..5f8b5e4 100644
--- a/arch/frv/include/asm/ptrace.h
+++ b/arch/frv/include/asm/ptrace.h
@@ -65,6 +65,8 @@
#ifdef __KERNEL__
#ifndef __ASSEMBLY__

+struct task_struct;
+
/*
* we dedicate GR28 to keeping a pointer to the current exception frame
* - gr28 is destroyed on entry to the kernel from userspace
@@ -73,11 +75,18 @@ register struct pt_regs *__frame asm("gr28");

#define user_mode(regs) (!((regs)->psr & PSR_S))
#define instruction_pointer(regs) ((regs)->pc)
+#define user_stack_pointer(regs) ((regs)->sp)

extern unsigned long user_stack(const struct pt_regs *);
extern void show_regs(struct pt_regs *);
#define profile_pc(regs) ((regs)->pc)
-#endif
+
+#define task_pt_regs(task) (task->thread.frame0)
+
+#define arch_has_single_step() (1)
+extern void user_enable_single_step(struct task_struct *);
+extern void user_disable_single_step(struct task_struct *);

#endif /* !__ASSEMBLY__ */
+#endif /* __KERNEL__ */
#endif /* _ASM_PTRACE_H */
diff --git a/arch/frv/include/asm/syscall.h b/arch/frv/include/asm/syscall.h
new file mode 100644
index 0000000..a82ede9
--- /dev/null
+++ b/arch/frv/include/asm/syscall.h
@@ -0,0 +1,123 @@
+/* syscall parameter access functions
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _ASM_SYSCALL_H
+#define _ASM_SYSCALL_H
+
+#include <linux/err.h>
+#include <asm/ptrace.h>
+
+/*
+ * Get the system call number or -1
+ */
+static inline long syscall_get_nr(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->syscallno;
+}
+
+/*
+ * Restore the clobbered GR8 register
+ * (1st syscall arg was overwritten with syscall return or error)
+ */
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->gr8 = regs->orig_gr8;
+}
+
+/*
+ * See if the syscall return value is an error, returning it if it is and 0 if
+ * not
+ */
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return IS_ERR_VALUE(regs->gr8) ? regs->gr8 : 0;
+}
+
+/*
+ * Get the syscall return value
+ */
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->gr8;
+}
+
+/*
+ * Set the syscall return value
+ */
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ if (error)
+ regs->gr8 = -error;
+ else
+ regs->gr8 = val;
+}
+
+/*
+ * Retrieve the system call arguments
+ */
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ unsigned long *args)
+{
+ /*
+ * Do this simply for now. If we need to start supporting
+ * fetching arguments from arbitrary indices, this will need some
+ * extra logic. Presently there are no in-tree users that depend
+ * on this behaviour.
+ */
+ BUG_ON(i);
+
+ /* Argument pattern is: GR8, GR9, GR10, GR11, GR12, GR13 */
+ switch (n) {
+ case 6: args[5] = regs->gr13;
+ case 5: args[4] = regs->gr12;
+ case 4: args[3] = regs->gr11;
+ case 3: args[2] = regs->gr10;
+ case 2: args[1] = regs->gr9;
+ case 1: args[0] = regs->gr8;
+ break;
+ default:
+ BUG();
+ }
+}
+
+/*
+ * Alter the system call arguments
+ */
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ const unsigned long *args)
+{
+ /* Same note as above applies */
+ BUG_ON(i);
+
+ switch (n) {
+ case 6: regs->gr13 = args[5];
+ case 5: regs->gr12 = args[4];
+ case 4: regs->gr11 = args[3];
+ case 3: regs->gr10 = args[2];
+ case 2: regs->gr9 = args[1];
+ case 1: regs->gr8 = args[0];
+ break;
+ default:
+ BUG();
+ }
+}
+
+#endif /* _ASM_SYSCALL_H */
diff --git a/arch/frv/kernel/entry.S b/arch/frv/kernel/entry.S
index 268dfbd..356e0e3 100644
--- a/arch/frv/kernel/entry.S
+++ b/arch/frv/kernel/entry.S
@@ -1149,11 +1149,10 @@ __entry_work_notifysig:
# perform syscall entry tracing
__syscall_trace_entry:
LEDS 0x6320
- setlos.p #0,gr8
- call do_syscall_trace
+ call syscall_trace_entry

- ldi @(gr28,#REG_SYSCALLNO),gr7
- lddi @(gr28,#REG_GR(8)) ,gr8
+ lddi.p @(gr28,#REG_GR(8)) ,gr8
+ ori gr8,#0,gr7 ; syscall_trace_entry() returned new syscallno
lddi @(gr28,#REG_GR(10)),gr10
lddi.p @(gr28,#REG_GR(12)),gr12

@@ -1168,11 +1167,10 @@ __syscall_exit_work:
beq icc0,#1,__entry_work_pending

movsg psr,gr23
- andi gr23,#~PSR_PIL,gr23 ; could let do_syscall_trace() call schedule()
+ andi gr23,#~PSR_PIL,gr23 ; could let syscall_trace_exit() call schedule()
movgs gr23,psr

- setlos.p #1,gr8
- call do_syscall_trace
+ call syscall_trace_exit
bra __entry_resume_userspace

__syscall_badsys:
diff --git a/arch/frv/kernel/ptrace.c b/arch/frv/kernel/ptrace.c
index 6b15e5d..e847945 100644
--- a/arch/frv/kernel/ptrace.c
+++ b/arch/frv/kernel/ptrace.c
@@ -19,6 +19,9 @@
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
+#include <linux/regset.h>
+#include <linux/elf.h>
+#include <linux/tracehook.h>

#include <asm/uaccess.h>
#include <asm/page.h>
@@ -33,6 +36,169 @@
*/

/*
+ * retrieve the contents of FRV userspace general registers
+ */
+static int genregs_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ const struct user_int_regs *iregs = &target->thread.user->i;
+ int ret;
+
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ iregs, 0, sizeof(*iregs));
+ if (ret < 0)
+ return ret;
+
+ return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+ sizeof(*iregs), -1);
+}
+
+/*
+ * update the contents of the FRV userspace general registers
+ */
+static int genregs_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ struct user_int_regs *iregs = &target->thread.user->i;
+ unsigned int offs_gr0, offs_gr1;
+ int ret;
+
+ /* not allowed to set PSR or __status */
+ if (pos < offsetof(struct user_int_regs, psr) + sizeof(long) &&
+ pos + count > offsetof(struct user_int_regs, psr))
+ return -EIO;
+
+ if (pos < offsetof(struct user_int_regs, __status) + sizeof(long) &&
+ pos + count > offsetof(struct user_int_regs, __status))
+ return -EIO;
+
+ /* set the control regs */
+ offs_gr0 = offsetof(struct user_int_regs, gr[0]);
+ offs_gr1 = offsetof(struct user_int_regs, gr[1]);
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ iregs, 0, offs_gr0);
+ if (ret < 0)
+ return ret;
+
+ /* skip GR0/TBR */
+ ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+ offs_gr0, offs_gr1);
+ if (ret < 0)
+ return ret;
+
+ /* set the general regs */
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ iregs, offs_gr1, sizeof(*iregs));
+ if (ret < 0)
+ return ret;
+
+ return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+ sizeof(*iregs), -1);
+}
+
+/*
+ * retrieve the contents of FRV userspace FP/Media registers
+ */
+static int fpmregs_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ const struct user_fpmedia_regs *fpregs = &target->thread.user->f;
+ int ret;
+
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ fpregs, 0, sizeof(*fpregs));
+ if (ret < 0)
+ return ret;
+
+ return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+ sizeof(*fpregs), -1);
+}
+
+/*
+ * update the contents of the FRV userspace FP/Media registers
+ */
+static int fpmregs_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ struct user_fpmedia_regs *fpregs = &target->thread.user->f;
+ int ret;
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+ fpregs, 0, sizeof(*fpregs));
+ if (ret < 0)
+ return ret;
+
+ return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+ sizeof(*fpregs), -1);
+}
+
+/*
+ * determine if the FP/Media registers have actually been used
+ */
+static int fpmregs_active(struct task_struct *target,
+ const struct user_regset *regset)
+{
+ return tsk_used_math(target) ? regset->n : 0;
+}
+
+/*
+ * Define the register sets available on the FRV under Linux
+ */
+enum frv_regset {
+ REGSET_GENERAL,
+ REGSET_FPMEDIA,
+};
+
+static const struct user_regset frv_regsets[] = {
+ /*
+ * General register format is:
+ * PSR, ISR, CCR, CCCR, LR, LCR, PC, (STATUS), SYSCALLNO, ORIG_G8
+ * GNER0-1, IACC0, TBR, GR1-63
+ */
+ [REGSET_GENERAL] = {
+ .core_note_type = NT_PRSTATUS,
+ .n = ELF_NGREG,
+ .size = sizeof(long),
+ .align = sizeof(long),
+ .get = genregs_get,
+ .set = genregs_set,
+ },
+ /*
+ * FPU/Media register format is:
+ * FR0-63, FNER0-1, MSR0-1, ACC0-7, ACCG0-8, FSR
+ */
+ [REGSET_FPMEDIA] = {
+ .core_note_type = NT_PRFPREG,
+ .n = sizeof(struct user_fpmedia_regs) / sizeof(long),
+ .size = sizeof(long),
+ .align = sizeof(long),
+ .get = fpmregs_get,
+ .set = fpmregs_set,
+ .active = fpmregs_active,
+ },
+};
+
+static const struct user_regset_view user_frv_native_view = {
+ .name = "frv",
+ .e_machine = EM_FRV,
+ .regsets = frv_regsets,
+ .n = ARRAY_SIZE(frv_regsets),
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+ return &user_frv_native_view;
+}
+
+/*
* Get contents of register REGNO in task TASK.
*/
static inline long get_reg(struct task_struct *task, int regno)
@@ -69,40 +235,23 @@ static inline int put_reg(struct task_struct *task, int regno,
}

/*
- * check that an address falls within the bounds of the target process's memory
- * mappings
- */
-static inline int is_user_addr_valid(struct task_struct *child,
- unsigned long start, unsigned long len)
-{
-#ifdef CONFIG_MMU
- if (start >= PAGE_OFFSET || len > PAGE_OFFSET - start)
- return -EIO;
- return 0;
-#else
- struct vm_area_struct *vma;
-
- vma = find_vma(child->mm, start);
- if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
- return 0;
-
- return -EIO;
-#endif
-}
-
-/*
* Called by kernel/ptrace.c when detaching..
*
* Control h/w single stepping
*/
-void ptrace_disable(struct task_struct *child)
+void user_enable_single_step(struct task_struct *child)
+{
+ child->thread.frame0->__status |= REG__STATUS_STEP;
+}
+
+void user_disable_single_step(struct task_struct *child)
{
child->thread.frame0->__status &= ~REG__STATUS_STEP;
}

-void ptrace_enable(struct task_struct *child)
+void ptrace_disable(struct task_struct *child)
{
- child->thread.frame0->__status |= REG__STATUS_STEP;
+ user_disable_single_step(child);
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
@@ -111,15 +260,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
int ret;

switch (request) {
- /* when I and D space are separate, these will need to be fixed. */
- case PTRACE_PEEKTEXT: /* read word at location addr. */
- case PTRACE_PEEKDATA:
- ret = -EIO;
- if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
- break;
- ret = generic_ptrace_peekdata(child, addr, data);
- break;
-
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
tmp = 0;
@@ -163,15 +303,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
break;
}

- /* when I and D space are separate, this will have to be fixed. */
- case PTRACE_POKETEXT: /* write the word at location addr. */
- case PTRACE_POKEDATA:
- ret = -EIO;
- if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
- break;
- ret = generic_ptrace_pokedata(child, addr, data);
- break;
-
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 3) || addr < 0)
@@ -179,7 +310,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)

ret = 0;
switch (addr >> 2) {
- case 0 ... PT__END-1:
+ case 0 ... PT__END - 1:
ret = put_reg(child, addr >> 2, data);
break;

@@ -189,95 +320,29 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
}
break;

- case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
- case PTRACE_CONT: /* restart after signal. */
- ret = -EIO;
- if (!valid_signal(data))
- break;
- if (request == PTRACE_SYSCALL)
- set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- else
- clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- child->exit_code = data;
- ptrace_disable(child);
- wake_up_process(child);
- ret = 0;
- break;
-
- /* make the child exit. Best I can do is send it a sigkill.
- * perhaps it should be put in the status that it wants to
- * exit.
- */
- case PTRACE_KILL:
- ret = 0;
- if (child->exit_state == EXIT_ZOMBIE) /* already dead */
- break;
- child->exit_code = SIGKILL;
- clear_tsk_thread_flag(child, TIF_SINGLESTEP);
- ptrace_disable(child);
- wake_up_process(child);
- break;
-
- case PTRACE_SINGLESTEP: /* set the trap flag. */
- ret = -EIO;
- if (!valid_signal(data))
- break;
- clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- ptrace_enable(child);
- child->exit_code = data;
- wake_up_process(child);
- ret = 0;
- break;
-
- case PTRACE_DETACH: /* detach a process that was attached. */
- ret = ptrace_detach(child, data);
- break;
-
- case PTRACE_GETREGS: { /* Get all integer regs from the child. */
- int i;
- for (i = 0; i < PT__GPEND; i++) {
- tmp = get_reg(child, i);
- if (put_user(tmp, (unsigned long *) data)) {
- ret = -EFAULT;
- break;
- }
- data += sizeof(long);
- }
- ret = 0;
- break;
- }
-
- case PTRACE_SETREGS: { /* Set all integer regs in the child. */
- int i;
- for (i = 0; i < PT__GPEND; i++) {
- if (get_user(tmp, (unsigned long *) data)) {
- ret = -EFAULT;
- break;
- }
- put_reg(child, i, tmp);
- data += sizeof(long);
- }
- ret = 0;
- break;
- }
-
- case PTRACE_GETFPREGS: { /* Get the child FP/Media state. */
- ret = 0;
- if (copy_to_user((void *) data,
- &child->thread.user->f,
- sizeof(child->thread.user->f)))
- ret = -EFAULT;
- break;
- }
-
- case PTRACE_SETFPREGS: { /* Set the child FP/Media state. */
- ret = 0;
- if (copy_from_user(&child->thread.user->f,
- (void *) data,
- sizeof(child->thread.user->f)))
- ret = -EFAULT;
- break;
- }
+ case PTRACE_GETREGS: /* Get all integer regs from the child. */
+ return copy_regset_to_user(child, &user_frv_native_view,
+ REGSET_GENERAL,
+ 0, sizeof(child->thread.user->i),
+ (void __user *)data);
+
+ case PTRACE_SETREGS: /* Set all integer regs in the child. */
+ return copy_regset_from_user(child, &user_frv_native_view,
+ REGSET_GENERAL,
+ 0, sizeof(child->thread.user->i),
+ (const void __user *)data);
+
+ case PTRACE_GETFPREGS: /* Get the child FP/Media state. */
+ return copy_regset_to_user(child, &user_frv_native_view,
+ REGSET_FPMEDIA,
+ 0, sizeof(child->thread.user->f),
+ (void __user *)data);
+
+ case PTRACE_SETFPREGS: /* Set the child FP/Media state. */
+ return copy_regset_from_user(child, &user_frv_native_view,
+ REGSET_FPMEDIA,
+ 0, sizeof(child->thread.user->f),
+ (const void __user *)data);

case PTRACE_GETFDPIC:
tmp = 0;
@@ -300,35 +365,36 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
break;

default:
- ret = -EIO;
+ ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}

-asmlinkage void do_syscall_trace(int leaving)
+/*
+ * handle tracing of system call entry
+ * - return the revised system call number or ULONG_MAX to cause ENOSYS
+ */
+asmlinkage unsigned long syscall_trace_entry(void)
{
- if (!test_thread_flag(TIF_SYSCALL_TRACE))
- return;
-
- if (!(current->ptrace & PT_PTRACED))
- return;
-
- /* we need to indicate entry or exit to strace */
- if (leaving)
- __frame->__status |= REG__STATUS_SYSC_EXIT;
- else
- __frame->__status |= REG__STATUS_SYSC_ENTRY;
+ __frame->__status |= REG__STATUS_SYSC_ENTRY;
+ if (tracehook_report_syscall_entry(__frame)) {
+ /* tracing decided this syscall should not happen, so
+ * We'll return a bogus call number to get an ENOSYS
+ * error, but leave the original number in
+ * __frame->syscallno
+ */
+ return ULONG_MAX;
+ }

- ptrace_notify(SIGTRAP);
+ return __frame->syscallno;
+}

- /*
- * this isn't the same as continuing with a signal, but it will do
- * for normal use. strace only continues with a signal if the
- * stopping signal is not SIGTRAP. -brl
- */
- if (current->exit_code) {
- send_sig(current->exit_code, current, 1);
- current->exit_code = 0;
- }
+/*
+ * handle tracing of system call exit
+ */
+asmlinkage void syscall_trace_exit(void)
+{
+ __frame->__status |= REG__STATUS_SYSC_EXIT;
+ tracehook_report_syscall_exit(__frame, 0);
}
diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c
index 7ae290a..4a7a62c 100644
--- a/arch/frv/kernel/signal.c
+++ b/arch/frv/kernel/signal.c
@@ -21,6 +21,7 @@
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/freezer.h>
+#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -516,6 +517,9 @@ static void do_signal(void)
* clear the TIF_RESTORE_SIGMASK flag */
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
+
+ tracehook_signal_handler(signr, &info, &ka, __frame,
+ test_thread_flag(TIF_SINGLESTEP));
}

return;
@@ -567,6 +571,7 @@ asmlinkage void do_notify_resume(__u32 thread_info_flags)
/* deal with notification on about to resume userspace execution */
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(__frame);
}

} /* end do_notify_resume() */


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