blob: a5e8b3b9d798301285b2db09b031dbba6c481875 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* arch/arm64/kernel/return_address.c
*
* Copyright (C) 2013 Linaro Limited
* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
*/
#include <linux/export.h>
#include <linux/ftrace.h>
#include <linux/kprobes.h>
#include <asm/stack_pointer.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;
}
}
NOKPROBE_SYMBOL(save_return_addr);
void *return_address(unsigned int level)
{
struct return_address_data data;
struct stackframe frame;
data.level = level + 2;
data.addr = NULL;
start_backtrace(&frame,
(unsigned long)__builtin_frame_address(0),
(unsigned long)return_address);
walk_stackframe(current, &frame, save_return_addr, &data);
if (!data.level)
return data.addr;
else
return NULL;
}
EXPORT_SYMBOL_GPL(return_address);
NOKPROBE_SYMBOL(return_address);