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/*
* Copyright (C) 2010-2013 Imagination Technologies Ltd.
*
* 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/oprofile.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/stacktrace.h>
#include "backtrace.h"
static void user_backtrace_fp(unsigned long __user *fp, unsigned int depth)
{
while (depth-- && access_ok(VERIFY_READ, fp, 8)) {
unsigned long addr;
unsigned long __user *fpnew;
if (__copy_from_user_inatomic(&addr, fp + 1, sizeof(addr)))
break;
addr -= 4;
oprofile_add_trace(addr);
/* stack grows up, so frame pointers must decrease */
if (__copy_from_user_inatomic(&fpnew, fp + 0, sizeof(fpnew)))
break;
if (fpnew >= fp)
break;
fp = fpnew;
}
}
static int kernel_backtrace_frame(struct stackframe *frame, void *data)
{
unsigned int *depth = data;
oprofile_add_trace(frame->pc);
/* decrement depth and stop if we reach 0 */
if ((*depth)-- == 0)
return 1;
/* otherwise onto the next frame */
return 0;
}
void metag_backtrace(struct pt_regs * const regs, unsigned int depth)
{
if (user_mode(regs)) {
unsigned long *fp = (unsigned long *)regs->ctx.AX[1].U0;
user_backtrace_fp((unsigned long __user __force *)fp, depth);
} else {
struct stackframe frame;
frame.fp = regs->ctx.AX[1].U0; /* A0FrP */
frame.sp = user_stack_pointer(regs); /* A0StP */
frame.lr = 0; /* from stack */
frame.pc = regs->ctx.CurrPC; /* PC */
walk_stackframe(&frame, &kernel_backtrace_frame, &depth);
}
}
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