1/*
 2 * arch/sh/kernel/return_address.c
 3 *
 4 * Copyright (C) 2009  Matt Fleming
 5 * Copyright (C) 2009  Paul Mundt
 6 *
 7 * This file is subject to the terms and conditions of the GNU General Public
 8 * License.  See the file "COPYING" in the main directory of this archive
 9 * for more details.
10 */
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <asm/dwarf.h>
14
15#ifdef CONFIG_DWARF_UNWINDER
16
17void *return_address(unsigned int depth)
18{
19	struct dwarf_frame *frame;
20	unsigned long ra;
21	int i;
22
23	for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
24		struct dwarf_frame *tmp;
25
26		tmp = dwarf_unwind_stack(ra, frame);
27		if (!tmp)
28			return NULL;
29
30		if (frame)
31			dwarf_free_frame(frame);
32
33		frame = tmp;
34
35		if (!frame || !frame->return_addr)
36			break;
37
38		ra = frame->return_addr;
39	}
40
41	/* Failed to unwind the stack to the specified depth. */
42	WARN_ON(i != depth + 1);
43
44	if (frame)
45		dwarf_free_frame(frame);
46
47	return (void *)ra;
48}
49
50#else
51
52void *return_address(unsigned int depth)
53{
54	return NULL;
55}
56
57#endif
58
59EXPORT_SYMBOL_GPL(return_address);

 1/*
 2 * arch/sh/kernel/return_address.c
 3 *
 4 * Copyright (C) 2009  Matt Fleming
 5 * Copyright (C) 2009  Paul Mundt
 6 *
 7 * This file is subject to the terms and conditions of the GNU General Public
 8 * License.  See the file "COPYING" in the main directory of this archive
 9 * for more details.
10 */
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <asm/dwarf.h>
14
15#ifdef CONFIG_DWARF_UNWINDER
16
17void *return_address(unsigned int depth)
18{
19	struct dwarf_frame *frame;
20	unsigned long ra;
21	int i;
22
23	for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
24		struct dwarf_frame *tmp;
25
26		tmp = dwarf_unwind_stack(ra, frame);
27		if (!tmp)
28			return NULL;
29
30		if (frame)
31			dwarf_free_frame(frame);
32
33		frame = tmp;
34
35		if (!frame || !frame->return_addr)
36			break;
37
38		ra = frame->return_addr;
39	}
40
41	/* Failed to unwind the stack to the specified depth. */
42	WARN_ON(i != depth + 1);
43
44	if (frame)
45		dwarf_free_frame(frame);
46
47	return (void *)ra;
48}
49
50#else
51
52void *return_address(unsigned int depth)
53{
54	return NULL;
55}
56
57#endif
58
59EXPORT_SYMBOL_GPL(return_address);