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);
57

source code of linux/arch/sh/kernel/return_address.c