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pthread_spin.c revision 1.1.2.2 
      1 /*	$NetBSD: pthread_spin.c,v 1.1.2.2 2008/01/09 01:36:39 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2001, 2006, 2007 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nathan J. Williams and Andrew Doran.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * Public (POSIX-specified) spinlocks.
     41  */
     42 
     43 #include <sys/cdefs.h>
     44 __RCSID("$NetBSD: pthread_spin.c,v 1.1.2.2 2008/01/09 01:36:39 matt Exp $");
     45 
     46 #include <sys/types.h>
     47 #include <sys/ras.h>
     48 
     49 #include <machine/lock.h>
     50 
     51 #include <errno.h>
     52 #include <unistd.h>
     53 #include <stdio.h>
     54 #include <stdlib.h>
     55 
     56 #include "pthread.h"
     57 #include "pthread_int.h"
     58 
     59 int
     60 pthread_spin_init(pthread_spinlock_t *lock, int pshared)
     61 {
     62 
     63 #ifdef ERRORCHECK
     64 	if (lock == NULL || (pshared != PTHREAD_PROCESS_PRIVATE &&
     65 	    pshared != PTHREAD_PROCESS_SHARED))
     66 		return EINVAL;
     67 #endif
     68 	lock->pts_magic = _PT_SPINLOCK_MAGIC;
     69 
     70 	/*
     71 	 * We don't actually use the pshared flag for anything;
     72 	 * CPU simple locks have all the process-shared properties
     73 	 * that we want anyway.
     74 	 */
     75 	lock->pts_flags = pshared;
     76 	pthread_lockinit(&lock->pts_spin);
     77 
     78 	return 0;
     79 }
     80 
     81 int
     82 pthread_spin_destroy(pthread_spinlock_t *lock)
     83 {
     84 
     85 #ifdef ERRORCHECK
     86 	if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC)
     87 		return EINVAL;
     88 	if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin))
     89 		return EBUSY;
     90 #endif
     91 
     92 	lock->pts_magic = _PT_SPINLOCK_DEAD;
     93 
     94 	return 0;
     95 }
     96 
     97 int
     98 pthread_spin_lock(pthread_spinlock_t *lock)
     99 {
    100 	pthread_t self;
    101 
    102 #ifdef ERRORCHECK
    103 	if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC)
    104 		return EINVAL;
    105 #endif
    106 
    107 	self = pthread__self();
    108 	while (pthread__spintrylock(self, &lock->pts_spin) == 0) {
    109 		pthread__smt_pause();
    110 	}
    111 
    112 	return 0;
    113 }
    114 
    115 int
    116 pthread_spin_trylock(pthread_spinlock_t *lock)
    117 {
    118 	pthread_t self;
    119 
    120 #ifdef ERRORCHECK
    121 	if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC)
    122 		return EINVAL;
    123 #endif
    124 
    125 	self = pthread__self();
    126 	if (pthread__spintrylock(self, &lock->pts_spin) == 0)
    127 		return EBUSY;
    128 	return 0;
    129 }
    130 
    131 int
    132 pthread_spin_unlock(pthread_spinlock_t *lock)
    133 {
    134 	pthread_t self;
    135 
    136 #ifdef ERRORCHECK
    137 	if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC)
    138 		return EINVAL;
    139 #endif
    140 
    141 	self = pthread__self();
    142 	pthread__spinunlock(self, &lock->pts_spin);
    143 
    144 	return 0;
    145 }
    146