[PATCH] Mark unwind info for signal trampolines in vDSOs

Mark unwind info for signal trampolines using the new S augmentation flag
introduced in: http://gcc.gnu.org/PR26208.

GCC 4.2 (or patched earlier GCC) will be able to special case unwinding
through frames right above signal trampolines.  As the augmentations start
with z flag and S is at the very end of the augmentation string, older GCCs
will just skip the S flag as unknown (that's why an augmentation flag was
chosen over say a new CFA opcode).

Signed-off-by: Jakub Jelinek <jakub@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/i386/kernel/vsyscall-sigreturn.S b/arch/i386/kernel/vsyscall-sigreturn.S
index fadb5bc3c374..a92262f41659 100644
--- a/arch/i386/kernel/vsyscall-sigreturn.S
+++ b/arch/i386/kernel/vsyscall-sigreturn.S
@@ -44,7 +44,7 @@ __kernel_rt_sigreturn:
 .LSTARTCIEDLSI1:
         .long 0                 /* CIE ID */
         .byte 1                 /* Version number */
-        .string "zR"            /* NUL-terminated augmentation string */
+        .string "zRS"           /* NUL-terminated augmentation string */
         .uleb128 1              /* Code alignment factor */
         .sleb128 -4             /* Data alignment factor */
         .byte 8                 /* Return address register column */