[PATCH] i386: reliable stack trace support (i386)

These are the i386-specific pieces to enable reliable stack traces. This is
going to be even more useful once CFI annotations get added to he assembly
code, namely to entry.S.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index cfc683f153b9..e802f3cac7e3 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -663,6 +663,35 @@ ENTRY(spurious_interrupt_bug)
         pushl $do_spurious_interrupt_bug
         jmp error_code
 
+#ifdef CONFIG_STACK_UNWIND
+ENTRY(arch_unwind_init_running)
+        movl    4(%esp), %edx
+        movl    (%esp), %ecx
+        leal    4(%esp), %eax
+        movl    %ebx, EBX(%edx)
+        xorl    %ebx, %ebx
+        movl    %ebx, ECX(%edx)
+        movl    %ebx, EDX(%edx)
+        movl    %esi, ESI(%edx)
+        movl    %edi, EDI(%edx)
+        movl    %ebp, EBP(%edx)
+        movl    %ebx, EAX(%edx)
+        movl    $__USER_DS, DS(%edx)
+        movl    $__USER_DS, ES(%edx)
+        movl    %ebx, ORIG_EAX(%edx)
+        movl    %ecx, EIP(%edx)
+        movl    12(%esp), %ecx
+        movl    $__KERNEL_CS, CS(%edx)
+        movl    %ebx, EFLAGS(%edx)
+        movl    %eax, OLDESP(%edx)
+        movl    8(%esp), %eax
+        movl    %ecx, 8(%esp)
+        movl    EBX(%edx), %ebx
+        movl    $__KERNEL_DS, OLDSS(%edx)
+        jmpl    *%eax
+ENDPROC(arch_unwind_init_running)
+#endif
+
 .section .rodata,"a"
 #include "syscall_table.S"