1 /* $NetBSD: pthread_spin.c,v 1.8 2020/02/05 11:05:10 kamil 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Public (POSIX-specified) spinlocks. 34 */ 35 36 #include <sys/cdefs.h> 37 __RCSID("$NetBSD: pthread_spin.c,v 1.8 2020/02/05 11:05:10 kamil Exp $"); 38 39 #include <sys/types.h> 40 #include <sys/ras.h> 41 42 #include <machine/lock.h> 43 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 49 #include "pthread.h" 50 #include "pthread_int.h" 51 52 int 53 pthread_spin_init(pthread_spinlock_t *lock, int pshared) 54 { 55 56 pthread__error(EINVAL, "Invalid pshared", 57 pshared == PTHREAD_PROCESS_PRIVATE || 58 pshared == PTHREAD_PROCESS_SHARED); 59 60 lock->pts_magic = _PT_SPINLOCK_MAGIC; 61 62 /* 63 * We don't actually use the pshared flag for anything; 64 * CPU simple locks have all the process-shared properties 65 * that we want anyway. 66 */ 67 lock->pts_flags = pshared; 68 pthread_lockinit(&lock->pts_spin); 69 70 return 0; 71 } 72 73 int 74 pthread_spin_destroy(pthread_spinlock_t *lock) 75 { 76 77 pthread__error(EINVAL, "Invalid spinlock", 78 lock->pts_magic == _PT_SPINLOCK_MAGIC); 79 80 if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin)) 81 return EBUSY; 82 83 lock->pts_magic = _PT_SPINLOCK_DEAD; 84 85 return 0; 86 } 87 88 int 89 pthread_spin_lock(pthread_spinlock_t *lock) 90 { 91 pthread_t self; 92 93 pthread__error(EINVAL, "Invalid spinlock", 94 lock->pts_magic == _PT_SPINLOCK_MAGIC); 95 96 self = pthread__self(); 97 while (pthread__spintrylock(self, &lock->pts_spin) == 0) { 98 pthread__smt_pause(); 99 } 100 101 return 0; 102 } 103 104 int 105 pthread_spin_trylock(pthread_spinlock_t *lock) 106 { 107 pthread_t self; 108 109 pthread__error(EINVAL, "Invalid spinlock", 110 lock->pts_magic == _PT_SPINLOCK_MAGIC); 111 112 self = pthread__self(); 113 if (pthread__spintrylock(self, &lock->pts_spin) == 0) 114 return EBUSY; 115 return 0; 116 } 117 118 int 119 pthread_spin_unlock(pthread_spinlock_t *lock) 120 { 121 pthread_t self; 122 123 pthread__error(EINVAL, "Invalid spinlock", 124 lock->pts_magic == _PT_SPINLOCK_MAGIC); 125 126 self = pthread__self(); 127 pthread__spinunlock(self, &lock->pts_spin); 128 pthread__smt_wake(); 129 130 return 0; 131 } 132