Re: CONFIG_HAVE_ARCH_TRACEHOOK and you

[Paul Mundt <lethal@linux-sh.org>]

On Thu, Sep 11, 2008 at 07:57:33PM -0700, Roland McGrath wrote:
> The comment in arch/Kconfig lists the items:
> 
> #	task_pt_regs()		in asm/processor.h or asm/ptrace.h
> #	arch_has_single_step()	if there is hardware single-step support
> #	arch_has_block_step()	if there is hardware block-step support
> #	arch_ptrace()		and not #define __ARCH_SYS_PTRACE
> #	compat_arch_ptrace()	and #define __ARCH_WANT_COMPAT_SYS_PTRACE
> #	asm/syscall.h		supplying asm-generic/syscall.h interface
> #	linux/regset.h		user_regset interfaces
> #	CORE_DUMP_USE_REGSET	#define'd in linux/elf.h
> #	TIF_SYSCALL_TRACE	calls tracehook_report_syscall_{entry,exit}
> #	TIF_NOTIFY_RESUME	calls tracehook_notify_resume()
> #	signal delivery		calls tracehook_signal_handler()
> 
[snip]

> Here's the text that's on that wiki:
> 
>     1. task_pt_regs()
> 
>           * Define this inline function in asm/processor.h or asm/ptrace.h.
> 
user_stack_pointer() is apparently a requirement, too. Although given
that you already have a task_struct pointer the only place you currently
use it (lib/syscall.c), it makes more sense to use KSTK_ESP/KSTK_EIP
which is provided by almost everyone already.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

---

 lib/syscall.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/syscall.c b/lib/syscall.c
index a4f7067..888c36a 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -11,8 +11,8 @@ static int collect_syscall(struct task_struct *target, long *callno,
 	if (unlikely(!regs))
 		return -EAGAIN;
 
-	*sp = user_stack_pointer(regs);
-	*pc = instruction_pointer(regs);
+	*sp = KSTK_ESP(target);
+	*pc = KSTK_EIP(target);
 
 	*callno = syscall_get_nr(target, regs);
 	if (*callno != -1L && maxargs > 0)