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