2 * arch/arm/kernel/return_address.c
4 * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
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.
11 #include <linux/module.h>
13 #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
14 #include <linux/sched.h>
16 #include <asm/stacktrace.h>
18 struct return_address_data {
23 static int save_return_addr(struct stackframe *frame, void *d)
25 struct return_address_data *data = d;
28 data->addr = (void *)frame->lr;
37 void *return_address(unsigned int level)
39 struct return_address_data data;
40 struct stackframe frame;
41 register unsigned long current_sp asm ("sp");
43 data.level = level + 1;
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;
50 walk_stackframe(&frame, save_return_addr, &data);
58 #else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
60 #if defined(CONFIG_ARM_UNWIND)
61 #warning "TODO: return_address should use unwind tables"
64 void *return_address(unsigned int level)
69 #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
71 EXPORT_SYMBOL_GPL(return_address);