On 11/09, Roland McGrath wrote:
>
> > Not sure I understand. You mean, if arch hook is not defined, we add
> > the default arch_fill_sigtrap_info (or whatever) which only sets si_signo?
>
> Right. To be more precise, I think the arch hook should only set what's
> arch-specific and nonzero, so have generic code zero-fill and set si_signo.
> The arch hook just sets si_code et al, so that if there is no arch hook
> then the default one is empty. The arch code will only ever define what it
> needs to add vs that default.
Oh... this adds more naming problems. And this way x86's send_sigtrap()
can't use this helper easily.
OK, please see below, but perhaps it is better to not introduce the
generic helper.
-------------------------------------------------------------------------------
> 1. specify arch hook, define default case
[PATCH 1/x] introduce user_single_step_siginfo()
perhaps user_single_step_siginfo() should go into ptrace.c ?
ARCH_HAS_USER_SINGLE_STEP_INFO doesn't match arch_has_single_step.
it should be ARCH_HAS_ARCH_USER_SINGLE_STEP_INFO, but this looks ugly.
I don't really care, up to you.
---
include/linux/ptrace.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- TH/include/linux/ptrace.h~1_ARCH_DEFAULT_HOOK 2009-10-30
00:46:06.000000000 +0100
+++ TH/include/linux/ptrace.h 2009-11-09 21:38:07.000000000 +0100
@@ -273,6 +273,25 @@ static inline void user_enable_block_ste
}
#endif /* arch_has_block_step */
+#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
+extern void arch_user_single_step_siginfo(struct task_struct *tsk,
+ struct pt_regs *regs, siginfo_t *info);
+#else
+static inline void arch_user_single_step_siginfo(struct task_struct *tsk,
+ struct pt_regs *regs, siginfo_t *info)
+{
+}
+#endif
+
+static inline void user_single_step_siginfo(struct task_struct *tsk,
+ struct pt_regs *regs, siginfo_t *info)
+{
+ memset(info, 0, sizeof(*info));
+ info->si_signo = SIGTRAP;
+
+ arch_user_single_step_siginfo(tsk, regs, info);
+}
+
#ifndef arch_ptrace_stop_needed
/**
* arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
--------------------------------------------------------------------------------
OK?
> 2. define powerpc's arch hook
[PATCH 2/x] change powepc
---
arch/powerpc/include/asm/ptrace.h | 2 ++
arch/powerpc/kernel/traps.c | 7 +++++++
2 files changed, 9 insertions(+)
--- TH/arch/powerpc/include/asm/ptrace.h~2_POWERPC 2009-11-09
21:32:17.000000000 +0100
+++ TH/arch/powerpc/include/asm/ptrace.h 2009-11-09 21:39:19.000000000
+0100
@@ -140,6 +140,8 @@ extern void user_enable_single_step(stru
extern void user_enable_block_step(struct task_struct *);
extern void user_disable_single_step(struct task_struct *);
+#define ARCH_HAS_USER_SINGLE_STEP_INFO
+
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
--- TH/arch/powerpc/kernel/traps.c~2_POWERPC 2009-11-09 21:32:17.000000000
+0100
+++ TH/arch/powerpc/kernel/traps.c 2009-11-09 21:39:39.000000000 +0100
@@ -174,6 +174,13 @@ int die(const char *str, struct pt_regs
return 0;
}
+void arch_user_single_step_siginfo(struct task_struct *tsk,
+ struct pt_regs *regs, siginfo_t *info)
+{
+ info->si_code = TRAP_TRACE;
+ info->si_addr = (void __user *) regs->nip;
+}
+
void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
siginfo_t info;
-------------------------------------------------------------------------------
Correct?
> 3. change tracehook_report_syscall_exit to look at step flag
[PATCH 3/x] change tracehook_report_syscall_exit() to look at step flag
---
include/linux/tracehook.h | 6 ++++++
1 file changed, 6 insertions(+)
--- TH/include/linux/tracehook.h~3_TRACEHOOK 2009-11-09 21:00:38.000000000
+0100
+++ TH/include/linux/tracehook.h 2009-11-09 21:42:16.000000000 +0100
@@ -134,6 +134,12 @@ static inline __must_check int tracehook
*/
static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int
step)
{
+ if (step) {
+ siginfo_t info;
+ user_single_step_siginfo(current, regs, &info);
+ force_sig_info(SIGTRAP, &info, current);
+ return;
+ }
ptrace_report_syscall(regs);
}
-----------------------------------------------------------------------------
> 4. define x86's arch hook
> 5. change x86 tracehook_report_syscall_exit to match common pattern
This is clear.
What do you think?
Oleg.
