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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> | |
12 | ||
13 | #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) | |
14 | #include <linux/sched.h> | |
15 | ||
16 | #include <asm/stacktrace.h> | |
17 | ||
18 | struct return_address_data { | |
19 | unsigned int level; | |
20 | void *addr; | |
21 | }; | |
22 | ||
23 | static int save_return_addr(struct stackframe *frame, void *d) | |
24 | { | |
25 | struct return_address_data *data = d; | |
26 | ||
27 | if (!data->level) { | |
28 | data->addr = (void *)frame->lr; | |
29 | ||
30 | return 1; | |
31 | } else { | |
32 | --data->level; | |
33 | return 0; | |
34 | } | |
35 | } | |
36 | ||
37 | void *return_address(unsigned int level) | |
38 | { | |
39 | struct return_address_data data; | |
40 | struct stackframe frame; | |
41 | register unsigned long current_sp asm ("sp"); | |
42 | ||
43 | data.level = level + 1; | |
44 | ||
45 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
46 | frame.sp = current_sp; | |
47 | frame.lr = (unsigned long)__builtin_return_address(0); | |
48 | frame.pc = (unsigned long)return_address; | |
49 | ||
50 | walk_stackframe(&frame, save_return_addr, &data); | |
51 | ||
52 | if (!data.level) | |
53 | return data.addr; | |
54 | else | |
55 | return NULL; | |
56 | } | |
57 | ||
58 | #else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */ | |
59 | ||
60 | #if defined(CONFIG_ARM_UNWIND) | |
61 | #warning "TODO: return_address should use unwind tables" | |
62 | #endif | |
63 | ||
64 | void *return_address(unsigned int level) | |
65 | { | |
66 | return NULL; | |
67 | } | |
68 | ||
69 | #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */ | |
70 | ||
71 | EXPORT_SYMBOL_GPL(return_address); |