82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
/*
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* Arm specific backtracing code for oprofile
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*
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* Copyright 2005 Openedhand Ltd.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*
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* Based on i386 oprofile backtrace code by John Levon, David Smith
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/uaccess.h>
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#include <asm/ptrace.h>
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#include "../kernel/stacktrace.h"
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static int report_trace(struct stackframe *frame, void *d)
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{
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unsigned int *depth = d;
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if (*depth) {
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oprofile_add_trace(frame->lr);
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(*depth)--;
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}
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return *depth == 0;
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}
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/*
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* The registers we're interested in are at the end of the variable
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* length saved register structure. The fp points at the end of this
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* structure so the address of this struct is:
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* (struct frame_tail *)(xxx->fp)-1
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*/
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struct frame_tail {
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struct frame_tail *fp;
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unsigned long sp;
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unsigned long lr;
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} __attribute__((packed));
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static struct frame_tail* user_backtrace(struct frame_tail *tail)
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{
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struct frame_tail buftail[2];
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/* Also check accessibility of one struct frame_tail beyond */
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if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
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return NULL;
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if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
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return NULL;
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oprofile_add_trace(buftail[0].lr);
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/* frame pointers should strictly progress back up the stack
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* (towards higher addresses) */
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if (tail >= buftail[0].fp)
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return NULL;
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return buftail[0].fp-1;
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}
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void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
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if (!user_mode(regs)) {
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unsigned long base = ((unsigned long)regs) & ~(THREAD_SIZE - 1);
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walk_stackframe(regs->ARM_fp, base, base + THREAD_SIZE,
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report_trace, &depth);
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return;
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}
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while (depth-- && tail && !((unsigned long) tail & 3))
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tail = user_backtrace(tail);
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}
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