[PATCH][SPARC64] Fix breakpointing in syscalls other than sigreturn

[jose.marchesi@oracle.com (Jose E. Marchesi)]

ping.  Could someone please take a look to this patch?  Thanks.

From: jose.marchesi@oracle.com (Jose E. Marchesi)
To: gdb-patches@sourceware.org
Subject: [PATCH][SPARC64] Fix breakpointing in syscalls other than sigreturn
Date: Tue, 10 Sep 2013 20:29:33 +0200

Hi.

This small patch makes sparc64_linux_step_trap to return 0 when a
breakpoint is set in a `ta 0x6d' which is not a sigreturn syscall.  In
these cases no rt_frame exists in the stack and thus the read PC is
wrong.

2013-09-10  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* sparc64-linux-tdep.c (sparc64_linux_step_trap): Make sure the
	trap is a sigreturn syscall.

Index: gdb/sparc64-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparc64-linux-tdep.c,v
retrieving revision 1.31
diff -u -r1.31 sparc64-linux-tdep.c
--- gdb/sparc64-linux-tdep.c	1 Jan 2013 06:32:51 -0000	1.31
+++ gdb/sparc64-linux-tdep.c	10 Sep 2013 18:17:25 -0000
@@ -111,7 +111,9 @@
 static CORE_ADDR
 sparc64_linux_step_trap (struct frame_info *frame, unsigned long insn)
 {
-  if (insn == 0x91d0206d)
+  /* __NR_rt_sigreturn is 101  */
+  if ((insn == 0x91d0206d)
+      && (get_frame_register_unsigned (frame, SPARC_G1_REGNUM) == 101))
     {
       struct gdbarch *gdbarch = get_frame_arch (frame);
       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);