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// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * arch/sh/kernel/return_address.c
 4 *
 5 * Copyright (C) 2009  Matt Fleming
 6 * Copyright (C) 2009  Paul Mundt
 
 
 
 
 7 */
 8#include <linux/kernel.h>
 9#include <linux/module.h>
10#include <asm/dwarf.h>
11
12#ifdef CONFIG_DWARF_UNWINDER
13
14void *return_address(unsigned int depth)
15{
16	struct dwarf_frame *frame;
17	unsigned long ra;
18	int i;
19
20	for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
21		struct dwarf_frame *tmp;
22
23		tmp = dwarf_unwind_stack(ra, frame);
24		if (!tmp)
25			return NULL;
26
27		if (frame)
28			dwarf_free_frame(frame);
29
30		frame = tmp;
31
32		if (!frame || !frame->return_addr)
33			break;
34
35		ra = frame->return_addr;
36	}
37
38	/* Failed to unwind the stack to the specified depth. */
39	WARN_ON(i != depth + 1);
40
41	if (frame)
42		dwarf_free_frame(frame);
43
44	return (void *)ra;
45}
46
47#else
48
49void *return_address(unsigned int depth)
50{
51	return NULL;
52}
53
54#endif
55
56EXPORT_SYMBOL_GPL(return_address);