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/*
* arch/sh/kernel/return_address.c
*
* Copyright (C) 2009 Matt Fleming
* Copyright (C) 2009 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/dwarf.h>
#ifdef CONFIG_DWARF_UNWINDER
void *return_address(unsigned int depth)
{
struct dwarf_frame *frame;
unsigned long ra;
int i;
for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
struct dwarf_frame *tmp;
tmp = dwarf_unwind_stack(ra, frame);
if (!tmp)
return NULL;
if (frame)
dwarf_free_frame(frame);
frame = tmp;
if (!frame || !frame->return_addr)
break;
ra = frame->return_addr;
}
/* Failed to unwind the stack to the specified depth. */
WARN_ON(i != depth + 1);
if (frame)
dwarf_free_frame(frame);
return (void *)ra;
}
#else
void *return_address(unsigned int depth)
{
return NULL;
}
#endif
EXPORT_SYMBOL_GPL(return_address);
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