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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
4bf1fa5a UKK |
2 | /* |
3 | * arch/arm/kernel/return_address.c | |
4 | * | |
5 | * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> | |
6 | * for Pengutronix | |
4bf1fa5a | 7 | */ |
ecea4ab6 | 8 | #include <linux/export.h> |
2bbd7e9b | 9 | #include <linux/ftrace.h> |
4bf1fa5a UKK |
10 | |
11 | #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) | |
12 | #include <linux/sched.h> | |
13 | ||
14 | #include <asm/stacktrace.h> | |
15 | ||
16 | struct return_address_data { | |
17 | unsigned int level; | |
18 | void *addr; | |
19 | }; | |
20 | ||
21 | static int save_return_addr(struct stackframe *frame, void *d) | |
22 | { | |
23 | struct return_address_data *data = d; | |
24 | ||
25 | if (!data->level) { | |
01223f36 | 26 | data->addr = (void *)frame->pc; |
4bf1fa5a UKK |
27 | |
28 | return 1; | |
29 | } else { | |
30 | --data->level; | |
31 | return 0; | |
32 | } | |
33 | } | |
34 | ||
35 | void *return_address(unsigned int level) | |
36 | { | |
37 | struct return_address_data data; | |
38 | struct stackframe frame; | |
4bf1fa5a | 39 | |
01223f36 KP |
40 | data.level = level + 2; |
41 | data.addr = NULL; | |
4bf1fa5a UKK |
42 | |
43 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
a556ee12 | 44 | frame.sp = current_stack_pointer; |
4bf1fa5a UKK |
45 | frame.lr = (unsigned long)__builtin_return_address(0); |
46 | frame.pc = (unsigned long)return_address; | |
47 | ||
48 | walk_stackframe(&frame, save_return_addr, &data); | |
49 | ||
50 | if (!data.level) | |
51 | return data.addr; | |
52 | else | |
53 | return NULL; | |
54 | } | |
55 | ||
15955e70 | 56 | #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */ |
4bf1fa5a UKK |
57 | |
58 | EXPORT_SYMBOL_GPL(return_address); |