From 79e7fd4f78e0c33e77dd0b69d7de8167a60af06a Mon Sep 17 00:00:00 2001
From: Yao Qi <yao.qi@linaro.org>
Date: Tue, 28 Jun 2016 12:02:36 +0100
Subject: [PATCH] Implement get_syscall_trapinfo for arm-linux

gdb/gdbserver:

2016-06-28  Yao Qi  <yao.qi@linaro.org>

	* linux-arm-low.c (arm_get_syscall_trapinfo): New function.
	(the_low_target): Install arm_get_syscall_trapinfo.
---
 gdb/gdbserver/ChangeLog       |  5 +++++
 gdb/gdbserver/linux-arm-low.c | 37 ++++++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 4c28195fb0e..f6f0ad97558 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-28  Yao Qi  <yao.qi@linaro.org>
+
+	* linux-arm-low.c (arm_get_syscall_trapinfo): New function.
+	(the_low_target): Install arm_get_syscall_trapinfo.
+
 2016-06-28  Yao Qi  <yao.qi@linaro.org>
 
 	* linux-aarch64-low.c (aarch64_get_syscall_trapinfo): New
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index 2ffda8731d1..e1261e54530 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -951,6 +951,40 @@ arm_supports_hardware_single_step (void)
   return 0;
 }
 
+/* Implementation of linux_target_ops method "get_syscall_trapinfo".  */
+
+static void
+arm_get_syscall_trapinfo (struct regcache *regcache, int *sysno)
+{
+  if (arm_is_thumb_mode ())
+    collect_register_by_name (regcache, "r7", sysno);
+  else
+    {
+      unsigned long pc;
+      unsigned long insn;
+
+      collect_register_by_name (regcache, "pc", &pc);
+
+      if ((*the_target->read_memory) (pc - 4, (unsigned char *) &insn, 4))
+	*sysno = UNKNOWN_SYSCALL;
+      else
+	{
+	  unsigned long svc_operand = (0x00ffffff & insn);
+
+	  if (svc_operand)
+	    {
+	      /* OABI */
+	      *sysno = svc_operand - 0x900000;
+	    }
+	  else
+	    {
+	      /* EABI */
+	      collect_register_by_name (regcache, "r7", sysno);
+	    }
+	}
+    }
+}
+
 /* Register sets without using PTRACE_GETREGSET.  */
 
 static struct regset_info arm_regsets[] = {
@@ -1031,7 +1065,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* get_min_fast_tracepoint_insn_len */
   NULL, /* supports_range_stepping */
   arm_breakpoint_kind_from_current_state,
-  arm_supports_hardware_single_step
+  arm_supports_hardware_single_step,
+  arm_get_syscall_trapinfo,
 };
 
 void
-- 
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