libgcc: AArch64: Check for correct signal insns on BE when unwinding

[Matthew Leach]

Hi,

When unwinding the stack, the unwind code checks for two opcodes that
denote a registrations of a signal handler. This is broken on BE as
the opcodes will be in the wrong byte-order as insns are always LE.

Add the correct checks when compiling for AArch64 big endian.

This has been tested with the glibc test "tst-backtrace4" and passes
with this patch applied.

Please note that I don't have commit access, if this is OK could
someone merge it for me?

Thanks,
Matt Leach

libgcc/
2013-11-26  Matthew Leach  <matthew.leach@arm.com>

	* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state):
	Check for correct opcodes on BE.

diff --git a/libgcc/config/aarch64/linux-unwind.h b/libgcc/config/aarch64/linux-unwind.h
index fde4d14..9f30b87 100644
--- a/libgcc/config/aarch64/linux-unwind.h
+++ b/libgcc/config/aarch64/linux-unwind.h
@@ -25,6 +25,14 @@
 #include <signal.h>
 #include <sys/ucontext.h>
 
+#if __AARCH64EB__
+#define MOVZ_X8_8B	0x681180d2
+#define SVC_0		0x010000d4
+#else
+#define MOVZ_X8_8B	0xd2801168
+#define SVC_0		0xd4000001
+#endif
+
 #define MD_FALLBACK_FRAME_STATE_FOR aarch64_fallback_frame_state
 
 static _Unwind_Reason_Code
@@ -55,7 +63,7 @@ aarch64_fallback_frame_state (struct _Unwind_Context *context,
      0xd2801168         movz x8, #0x8b
      0xd4000001         svc  0x0
    */
-  if (pc[0] != 0xd2801168 || pc[1] != 0xd4000001)
+  if (pc[0] != MOVZ_X8_8B || pc[1] != SVC_0)
     {
       return _URC_END_OF_STACK;
     }
-- 
1.7.9.5