[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>
diff --git a/arch/powerpc/kernel/vdso64/sigtramp.S b/arch/powerpc/kernel/vdso64/sigtramp.S
index 31b604a..7479edb 100644
--- a/arch/powerpc/kernel/vdso64/sigtramp.S
+++ b/arch/powerpc/kernel/vdso64/sigtramp.S
@@ -263,7 +263,7 @@
.Lcie_start:
.long 0 /* CIE ID */
.byte 1 /* Version number */
- .string "zR" /* NUL-terminated augmentation string */
+ .string "zRS" /* NUL-terminated augmentation string */
.uleb128 4 /* Code alignment factor */
.sleb128 -8 /* Data alignment factor */
.byte 67 /* Return address register column, ap */