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authorMasami Hiramatsu <mhiramat@redhat.com>2009-05-11 17:03:00 -0400
committerIngo Molnar <mingo@elte.hu>2009-05-12 00:39:52 +0200
commit7b6c6c77732ca1d2498eda7eabb64f9648896e96 (patch)
treef5eccbffc028d396e454898db1edc66e7e6a4666 /arch/x86/include
parent3c598766a2bae1b208470e7cc934ac462561e3cb (diff)
x86, 32-bit: fix kernel_trap_sp()
Use &regs->sp instead of regs for getting the top of stack in kernel mode. (on x86-64, regs->sp always points the top of stack) [ Impact: Oprofile decodes only stack for backtracing on i386 ] Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> [ v2: rename the API to kernel_stack_pointer(), move variable inside ] Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: systemtap@sources.redhat.com Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Jan Blunck <jblunck@suse.de> Cc: Christoph Hellwig <hch@infradead.org> LKML-Reference: <20090511210300.17332.67549.stgit@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/ptrace.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index e304b66abee..624f133943e 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -187,14 +187,15 @@ static inline int v8086_mode(struct pt_regs *regs)
/*
* X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode
- * when it traps. So regs will be the current sp.
+ * when it traps. The previous stack will be directly underneath the saved
+ * registers, and 'sp/ss' won't even have been saved. Thus the '&regs->sp'.
*
* This is valid only for kernel mode traps.
*/
-static inline unsigned long kernel_trap_sp(struct pt_regs *regs)
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
{
#ifdef CONFIG_X86_32
- return (unsigned long)regs;
+ return (unsigned long)(&regs->sp);
#else
return regs->sp;
#endif