From b0598c10f1b7b7bd9bf35849883d6e2c87da18d3 Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@gmail.com>
Date: Mon, 8 Apr 2013 01:29:19 +0400
Subject: [PATCH] --- yaml --- r: 374982 b: refs/heads/master c:
 3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/xtensa/include/asm/ftrace.h | 34 +++++++++++++++++++++++++-
 trunk/arch/xtensa/kernel/stacktrace.c  | 33 +++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 95c1c935e1f8..7ce44de5f1be 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3e4196a5cc9cff50900f3dc8acc3d41e5963fd50
+refs/heads/master: 3ae908c99e944a7a5c4f4b2d8c603a6bc57b728b
diff --git a/trunk/arch/xtensa/include/asm/ftrace.h b/trunk/arch/xtensa/include/asm/ftrace.h
index 40a8c178f10d..36dc7a684397 100644
--- a/trunk/arch/xtensa/include/asm/ftrace.h
+++ b/trunk/arch/xtensa/include/asm/ftrace.h
@@ -1 +1,33 @@
-/* empty */
+/*
+ * arch/xtensa/include/asm/ftrace.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2013 Tensilica Inc.
+ */
+#ifndef _XTENSA_FTRACE_H
+#define _XTENSA_FTRACE_H
+
+#include <asm/processor.h>
+
+#define HAVE_ARCH_CALLER_ADDR
+#define CALLER_ADDR0 ({ unsigned long a0, a1; \
+		__asm__ __volatile__ ( \
+			"mov %0, a0\n" \
+			"mov %1, a1\n" \
+			: "=r"(a0), "=r"(a1) : : ); \
+		MAKE_PC_FROM_RA(a0, a1); })
+#ifdef CONFIG_FRAME_POINTER
+extern unsigned long return_address(unsigned level);
+#define CALLER_ADDR1 return_address(1)
+#define CALLER_ADDR2 return_address(2)
+#define CALLER_ADDR3 return_address(3)
+#else
+#define CALLER_ADDR1 (0)
+#define CALLER_ADDR2 (0)
+#define CALLER_ADDR3 (0)
+#endif
+
+#endif /* _XTENSA_FTRACE_H */
diff --git a/trunk/arch/xtensa/kernel/stacktrace.c b/trunk/arch/xtensa/kernel/stacktrace.c
index e3aff9575183..7d2c317bd98b 100644
--- a/trunk/arch/xtensa/kernel/stacktrace.c
+++ b/trunk/arch/xtensa/kernel/stacktrace.c
@@ -85,3 +85,36 @@ void save_stack_trace(struct stack_trace *trace)
 EXPORT_SYMBOL_GPL(save_stack_trace);
 
 #endif
+
+#ifdef CONFIG_FRAME_POINTER
+
+struct return_addr_data {
+	unsigned long addr;
+	unsigned skip;
+};
+
+static int return_address_cb(struct stackframe *frame, void *data)
+{
+	struct return_addr_data *r = data;
+
+	if (r->skip) {
+		--r->skip;
+		return 0;
+	}
+	if (!kernel_text_address(frame->pc))
+		return 0;
+	r->addr = frame->pc;
+	return 1;
+}
+
+unsigned long return_address(unsigned level)
+{
+	struct return_addr_data r = {
+		.skip = level + 1,
+	};
+	walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
+	return r.addr;
+}
+EXPORT_SYMBOL(return_address);
+
+#endif