// SPDX-License-Identifier: GPL-2.0-only
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/*
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* arch/arm/kernel/return_address.c
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*
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* Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
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* for Pengutronix
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*/
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#include <linux/export.h>
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#include <linux/ftrace.h>
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#include <linux/sched.h>
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#include <asm/stacktrace.h>
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struct return_address_data {
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unsigned int level;
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void *addr;
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};
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static int save_return_addr(struct stackframe *frame, void *d)
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{
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struct return_address_data *data = d;
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if (!data->level) {
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data->addr = (void *)frame->pc;
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return 1;
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} else {
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--data->level;
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return 0;
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}
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}
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void *return_address(unsigned int level)
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{
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struct return_address_data data;
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struct stackframe frame;
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data.level = level + 2;
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data.addr = NULL;
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frame.fp = (unsigned long)__builtin_frame_address(0);
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frame.sp = current_stack_pointer;
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frame.lr = (unsigned long)__builtin_return_address(0);
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frame.pc = (unsigned long)return_address;
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walk_stackframe(&frame, save_return_addr, &data);
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if (!data.level)
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return data.addr;
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else
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return NULL;
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}
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EXPORT_SYMBOL_GPL(return_address);
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