Cregit: return_address.c

Contributors: 5
Author	Tokens	Token Proportion	Commits	Commit Proportion
Uwe Kleine-König	191	93.63%	2	33.33%
Keun-O Park	8	3.92%	1	16.67%
Russell King	3	1.47%	1	16.67%
Paul Gortmaker	1	0.49%	1	16.67%
Behan Webster	1	0.49%	1	16.67%
Total	204		6

/*
 * arch/arm/kernel/return_address.c
 *
 * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
 * for Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */
#include <linux/export.h>
#include <linux/ftrace.h>

#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
#include <linux/sched.h>

#include <asm/stacktrace.h>

struct return_address_data {
	unsigned int level;
	void *addr;
};

static int save_return_addr(struct stackframe *frame, void *d)
{
	struct return_address_data *data = d;

	if (!data->level) {
		data->addr = (void *)frame->pc;

		return 1;
	} else {
		--data->level;
		return 0;
	}
}

void *return_address(unsigned int level)
{
	struct return_address_data data;
	struct stackframe frame;

	data.level = level + 2;
	data.addr = NULL;

	frame.fp = (unsigned long)__builtin_frame_address(0);
	frame.sp = current_stack_pointer;
	frame.lr = (unsigned long)__builtin_return_address(0);
	frame.pc = (unsigned long)return_address;

	walk_stackframe(&frame, save_return_addr, &data);

	if (!data.level)
		return data.addr;
	else
		return NULL;
}

#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */

EXPORT_SYMBOL_GPL(return_address);