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
11#include <asm/dwarf.h>
12#include <asm/ftrace.h>
13
14#ifdef CONFIG_DWARF_UNWINDER
15
16void *return_address(unsigned int depth)
17{
18	struct dwarf_frame *frame;
19	unsigned long ra;
20	int i;
21
22	for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
23		struct dwarf_frame *tmp;
24
25		tmp = dwarf_unwind_stack(ra, frame);
26		if (!tmp)
27			return NULL;
28
29		if (frame)
30			dwarf_free_frame(frame);
31
32		frame = tmp;
33
34		if (!frame || !frame->return_addr)
35			break;
36
37		ra = frame->return_addr;
38	}
39
40	/* Failed to unwind the stack to the specified depth. */
41	WARN_ON(i != depth + 1);
42
43	if (frame)
44		dwarf_free_frame(frame);
45
46	return (void *)ra;
47}
48
49#else
50
51void *return_address(unsigned int depth)
52{
53	return NULL;
54}
55
56#endif
57
58EXPORT_SYMBOL_GPL(return_address);