Cregit: Linux 5.16: return

Contributors: 7
Author	Tokens	Token Proportion	Commits	Commit Proportion
Uwe Kleine-König	175	84.54%	1	14.29%
Masami Hiramatsu	17	8.21%	1	14.29%
Keun-O Park	8	3.86%	1	14.29%
Russell King	3	1.45%	1	14.29%
Thomas Gleixner	2	0.97%	1	14.29%
Behan Webster	1	0.48%	1	14.29%
Paul Gortmaker	1	0.48%	1	14.29%
Total	207		7

// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch/arm/kernel/return_address.c
 *
 * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
 * for Pengutronix
 */
#include <linux/export.h>
#include <linux/ftrace.h>
#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;
#ifdef CONFIG_KRETPROBES
	frame.kr_cur = NULL;
	frame.tsk = current;
#endif

	walk_stackframe(&frame, save_return_addr, &data);

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

EXPORT_SYMBOL_GPL(return_address);