projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 3711784e AT |
1 | /* |
| 2 | * arch/arm64/kernel/return_address.c | |
| 3 | * | |
| 4 | * Copyright (C) 2013 Linaro Limited | |
| 5 | * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or modify | |
| 8 | * it under the terms of the GNU General Public License version 2 as | |
| 9 | * published by the Free Software Foundation. | |
| 10 | */ | |
| 11 | ||
| 12 | #include <linux/export.h> | |
| 13 | #include <linux/ftrace.h> | |
| 14 | ||
| 15 | #include <asm/stacktrace.h> | |
| 16 | ||
| 17 | struct return_address_data { | |
| 18 | unsigned int level; | |
| 19 | void *addr; | |
| 20 | }; | |
| 21 | ||
| 22 | static int save_return_addr(struct stackframe *frame, void *d) | |
| 23 | { | |
| 24 | struct return_address_data *data = d; | |
| 25 | ||
| 26 | if (!data->level) { | |
| 27 | data->addr = (void *)frame->pc; | |
| 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; | |
| 3711784e AT |
39 | |
| 40 | data.level = level + 2; | |
| 41 | data.addr = NULL; | |
| 42 | ||
| 43 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
| a4ceab1a | 44 | frame.sp = current_stack_pointer; |
| 3711784e AT |
45 | frame.pc = (unsigned long)return_address; /* dummy */ |
| 46 | ||
| 47 | walk_stackframe(&frame, save_return_addr, &data); | |
| 48 | ||
| 49 | if (!data.level) | |
| 50 | return data.addr; | |
| 51 | else | |
| 52 | return NULL; | |
| 53 | } | |
| 54 | EXPORT_SYMBOL_GPL(return_address); |