82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
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/*
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* AVR32 specific backtracing code for oprofile
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*
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* Copyright 2008 Weinmann GmbH
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*
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* Author: Nikolaus Voss <n.voss@weinmann.de>
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*
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* Based on i386 oprofile backtrace code by John Levon and 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/uaccess.h>
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/* The first two words of each frame on the stack look like this if we have
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* frame pointers */
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struct frame_head {
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unsigned long lr;
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struct frame_head *fp;
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};
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/* copied from arch/avr32/kernel/process.c */
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static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
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{
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return (p > (unsigned long)tinfo)
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&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
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}
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/* copied from arch/x86/oprofile/backtrace.c */
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static struct frame_head *dump_user_backtrace(struct frame_head *head)
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{
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struct frame_head bufhead[2];
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/* Also check accessibility of one struct frame_head beyond */
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if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
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return NULL;
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if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
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return NULL;
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oprofile_add_trace(bufhead[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 (bufhead[0].fp <= head)
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return NULL;
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return bufhead[0].fp;
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}
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void avr32_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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/* Get first frame pointer */
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struct frame_head *head = (struct frame_head *)(regs->r7);
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if (!user_mode(regs)) {
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#ifdef CONFIG_FRAME_POINTER
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/*
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* Traverse the kernel stack from frame to frame up to
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* "depth" steps.
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*/
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while (depth-- && valid_stack_ptr(task_thread_info(current),
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(unsigned long)head)) {
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oprofile_add_trace(head->lr);
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if (head->fp <= head)
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break;
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head = head->fp;
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}
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#endif
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} else {
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/* Assume we have frame pointers in user mode process */
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while (depth-- && head)
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head = dump_user_backtrace(head);
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}
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}
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