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- // 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 bool save_return_addr(void *d, unsigned long pc)
- {
- struct return_address_data *data = d;
- if (!data->level) {
- data->addr = (void *)pc;
- return false;
- } else {
- --data->level;
- return true;
- }
- }
- 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);
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