109 lines
3.8 KiB
C
109 lines
3.8 KiB
C
/*
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* Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: uthread_spinlock.c,v 1.3 1998/06/06 07:27:06 jb Exp $
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*
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*/
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#include <stdio.h>
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#include <sched.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <string.h>
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#include "pthread_private.h"
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extern char *__progname;
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/*
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* Lock a location for the running thread. Yield to allow other
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* threads to run if this thread is blocked because the lock is
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* not available. Note that this function does not sleep. It
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* assumes that the lock will be available very soon.
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*/
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void
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_spinlock(spinlock_t *lck)
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{
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/*
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* Try to grab the lock and loop if another thread grabs
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* it before we do.
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*/
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while(_atomic_lock(&lck->access_lock)) {
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/* Give up the time slice: */
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sched_yield();
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/* Check if already locked by the running thread: */
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if (lck->lock_owner == (long) _thread_run)
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return;
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}
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/* The running thread now owns the lock: */
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lck->lock_owner = (long) _thread_run;
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}
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/*
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* Lock a location for the running thread. Yield to allow other
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* threads to run if this thread is blocked because the lock is
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* not available. Note that this function does not sleep. It
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* assumes that the lock will be available very soon.
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*
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* This function checks if the running thread has already locked the
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* location, warns if this occurs and creates a thread dump before
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* returning.
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*/
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void
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_spinlock_debug(spinlock_t *lck, char *fname, int lineno)
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{
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/*
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* Try to grab the lock and loop if another thread grabs
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* it before we do.
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*/
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while(_atomic_lock(&lck->access_lock)) {
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/* Give up the time slice: */
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sched_yield();
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/* Check if already locked by the running thread: */
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if (lck->lock_owner == (long) _thread_run) {
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char str[256];
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snprintf(str, sizeof(str), "%s - Warning: Thread %p attempted to lock %p from %s (%d) which it had already locked in %s (%d)\n", __progname, _thread_run, lck, fname, lineno, lck->fname, lck->lineno);
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_thread_sys_write(2,str,strlen(str));
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/* Create a thread dump to help debug this problem: */
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_thread_dump_info();
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return;
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}
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}
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/* The running thread now owns the lock: */
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lck->lock_owner = (long) _thread_run;
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lck->fname = fname;
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lck->lineno = lineno;
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}
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