72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/module.h>
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#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
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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->lr;
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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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register unsigned long current_sp asm ("sp");
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data.level = level + 1;
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frame.fp = (unsigned long)__builtin_frame_address(0);
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frame.sp = current_sp;
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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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#else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
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#if defined(CONFIG_ARM_UNWIND)
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#warning "TODO: return_address should use unwind tables"
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#endif
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void *return_address(unsigned int level)
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{
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return NULL;
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}
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#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
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EXPORT_SYMBOL_GPL(return_address);
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