This changeset 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.

ChangeLog
2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* sparc64-linux-tdep.c (sparc64_linux_step_trap): Get PC from
          the sigreturn register save area only if the syscall is
          sigreturn.

testsuite/ChangeLog
2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* gdb.arch/sparc-sysstep.exp: New file.
	* gdb.arch/sparc-sysstep.c: Likewise.

	* gdb.arch/Makefile.in (EXECUTABLES): Add sparc-sysstep.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>
+
+	* sparc64-linux-tdep.c (sparc64_linux_step_trap): Get PC from
+          the sigreturn register save area only if the syscall is
+          sigreturn.
+
 2014-01-29  Joel Brobecker  <brobecker@adacore.com>
 
 	* valops.c (value_slice): Minor reformatting.

gdb/sparc64-linux-tdep.c

@@ -111,7 +111,9 @@ sparc64_linux_sigframe_init (const struct tramp_frame *self,
 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);

gdb/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>
+
+	* gdb.arch/sparc-sysstep.exp: New file.
+	* gdb.arch/sparc-sysstep.c: Likewise.
+
+	* gdb.arch/Makefile.in (EXECUTABLES): Add sparc-sysstep.
+
 2014-01-28  Edjunior Barbosa Machado  <emachado@linux.vnet.ibm.com>
 
 	* gdb.base/info-shared.exp: Expect leading `.' on ppc64's symbols.

gdb/testsuite/gdb.arch/Makefile.in

@@ -3,7 +3,7 @@ srcdir = @srcdir@
 
 EXECUTABLES = altivec-abi altivec-regs amd64-byte amd64-disp-step amd64-dword \
 	amd64-entry-value amd64-i386-address amd64-word i386-bp_permanent \
-	i386-permbkpt i386-avx i386-signal i386-sse
+	i386-permbkpt i386-avx i386-signal i386-sse sparc-sysstep
 
 all info install-info dvi install uninstall installcheck check:
 	@echo "Nothing to be done for $@..."

gdb/testsuite/gdb.arch/sparc-sysstep.c

@@ -0,0 +1,35 @@
+/* Test single-stepping system call instructions in sparc.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <signal.h>
+
+int global;
+
+static void
+handler (int sig)
+{
+}
+
+int
+main ()
+{
+  signal (SIGALRM, handler);
+  kill (getpid (), SIGALRM);
+  return 0; /* sparc-sysstep.exp: last */
+}

gdb/testsuite/gdb.arch/sparc-sysstep.exp

@@ -0,0 +1,49 @@
+# Copyright 2014 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file is part of the gdb testsuite.
+
+# Test single-stepping system call instructions (ta 0x6d) in the two
+# cases distinguished by the implementation: sigreturn and all others.
+# The sigreturn syscall requires a special analysis since the return
+# PC must be extracted from the sigreturn register save area in the
+# stack.
+
+if ![istarget "sparc*-*-linux*"] then {
+    return 0
+}
+
+set testfile sparc-sysstep
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+set opts {}
+
+if {[prepare_for_testing ${testfile}.exp ${binfile} $srcfile {additional_flags=-g}]} {
+    return -1
+}
+
+if ![runto_main] {
+    return -1
+}
+
+# Watching the global variable will guarantee that gdb will
+# single-step through the whole program.
+
+set lno [gdb_get_line_number "sparc-sysstep.exp: last" $srcfile]
+
+gdb_test "break $srcfile:$lno" "Breakpoint \[0-9\] at .*"
+gdb_test_no_output "set can-use-hw-watchpoints 0" ""
+gdb_test "watch global" "Watchpoint .*: global"
+gdb_test "continue" "Continuing.*${srcfile}:${lno}.*"