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4bf1fa5a UKK |
1 | /* |
2 | * arch/arm/kernel/return_address.c | |
3 | * | |
4 | * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> | |
5 | * for Pengutronix | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License version 2 as published by | |
9 | * the Free Software Foundation. | |
10 | */ | |
11 | #include <linux/module.h> | |
2bbd7e9b | 12 | #include <linux/ftrace.h> |
4bf1fa5a UKK |
13 | |
14 | #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) | |
15 | #include <linux/sched.h> | |
16 | ||
17 | #include <asm/stacktrace.h> | |
18 | ||
19 | struct return_address_data { | |
20 | unsigned int level; | |
21 | void *addr; | |
22 | }; | |
23 | ||
24 | static int save_return_addr(struct stackframe *frame, void *d) | |
25 | { | |
26 | struct return_address_data *data = d; | |
27 | ||
28 | if (!data->level) { | |
29 | data->addr = (void *)frame->lr; | |
30 | ||
31 | return 1; | |
32 | } else { | |
33 | --data->level; | |
34 | return 0; | |
35 | } | |
36 | } | |
37 | ||
38 | void *return_address(unsigned int level) | |
39 | { | |
40 | struct return_address_data data; | |
41 | struct stackframe frame; | |
42 | register unsigned long current_sp asm ("sp"); | |
43 | ||
44 | data.level = level + 1; | |
45 | ||
46 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
47 | frame.sp = current_sp; | |
48 | frame.lr = (unsigned long)__builtin_return_address(0); | |
49 | frame.pc = (unsigned long)return_address; | |
50 | ||
51 | walk_stackframe(&frame, save_return_addr, &data); | |
52 | ||
53 | if (!data.level) | |
54 | return data.addr; | |
55 | else | |
56 | return NULL; | |
57 | } | |
58 | ||
59 | #else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */ | |
60 | ||
61 | #if defined(CONFIG_ARM_UNWIND) | |
62 | #warning "TODO: return_address should use unwind tables" | |
63 | #endif | |
64 | ||
65 | void *return_address(unsigned int level) | |
66 | { | |
67 | return NULL; | |
68 | } | |
69 | ||
70 | #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */ | |
71 | ||
72 | EXPORT_SYMBOL_GPL(return_address); |