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// SPDX-License-Identifier: GPL-2.0-only
/*
* This code come from arch/arm64/kernel/return_address.c
*
* Copyright (C) 2023 SiFive.
*/
#include <linux/export.h>
#include <linux/kprobes.h>
#include <linux/stacktrace.h>
struct return_address_data {
unsigned int level;
void *addr;
};
static bool save_return_addr(void *d, unsigned long pc)
{
struct return_address_data *data = d;
if (!data->level) {
data->addr = (void *)pc;
return false;
}
--data->level;
return true;
}
NOKPROBE_SYMBOL(save_return_addr);
noinline void *return_address(unsigned int level)
{
struct return_address_data data;
data.level = level + 3;
data.addr = NULL;
arch_stack_walk(save_return_addr, &data, current, NULL);
if (!data.level)
return data.addr;
else
return NULL;
}
EXPORT_SYMBOL_GPL(return_address);
NOKPROBE_SYMBOL(return_address);
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