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141 lines
3.5 KiB
C
141 lines
3.5 KiB
C
/*-
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* Copyright (c) 2003 David Xu <davidxu@freebsd.org>
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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#include "namespace.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include "un-namespace.h"
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#include "thr_private.h"
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#define SPIN_COUNT 100000
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__weak_reference(_pthread_spin_init, pthread_spin_init);
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__weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
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__weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
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__weak_reference(_pthread_spin_lock, pthread_spin_lock);
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__weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
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int
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_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
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{
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struct pthread_spinlock *lck;
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int ret;
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if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
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ret = EINVAL;
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else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
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ret = ENOMEM;
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else {
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_thr_umutex_init(&lck->s_lock);
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*lock = lck;
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ret = 0;
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}
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return (ret);
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}
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int
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_pthread_spin_destroy(pthread_spinlock_t *lock)
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{
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int ret;
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if (lock == NULL || *lock == NULL)
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ret = EINVAL;
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else {
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free(*lock);
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*lock = NULL;
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ret = 0;
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}
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return (ret);
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}
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int
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_pthread_spin_trylock(pthread_spinlock_t *lock)
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{
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struct pthread *curthread = _get_curthread();
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struct pthread_spinlock *lck;
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int ret;
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if (lock == NULL || (lck = *lock) == NULL)
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ret = EINVAL;
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else
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ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock);
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return (ret);
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}
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int
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_pthread_spin_lock(pthread_spinlock_t *lock)
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{
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struct pthread *curthread = _get_curthread();
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struct pthread_spinlock *lck;
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int ret, count;
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if (lock == NULL || (lck = *lock) == NULL)
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ret = EINVAL;
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else {
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count = SPIN_COUNT;
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while ((ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock)) != 0) {
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while (lck->s_lock.m_owner) {
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if (_thr_smp_cpus <= 1) {
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_pthread_yield();
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} else {
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#if defined(__i386__) || defined(__x86_64__)
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/* tell cpu we are spinning */
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__asm __volatile("pause");
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#endif
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if (--count <= 0) {
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count = SPIN_COUNT;
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_pthread_yield();
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}
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}
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}
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}
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ret = 0;
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}
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return (ret);
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}
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int
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_pthread_spin_unlock(pthread_spinlock_t *lock)
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{
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struct pthread *curthread = _get_curthread();
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struct pthread_spinlock *lck;
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int ret;
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if (lock == NULL || (lck = *lock) == NULL)
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ret = EINVAL;
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else {
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ret = THR_UMUTEX_UNLOCK(curthread, &lck->s_lock);
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}
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return (ret);
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}
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