1/* $NetBSD: pthread_spin.c,v 1.11 2023/05/25 14:30:03 riastradh 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 1.11 2023/05/25 14:30:03 riastradh Exp $"); 38 39/* Need to use libc-private names for atomic operations. */ 40#include "../../common/lib/libc/atomic/atomic_op_namespace.h" 41 42#include <sys/types.h> 43#include <sys/ras.h> 44 45#include <machine/lock.h> 46 47#include <errno.h> 48#include <unistd.h> 49#include <stdio.h> 50#include <stdlib.h> 51 52#include "pthread.h" 53#include "pthread_int.h" 54 55int 56pthread_spin_init(pthread_spinlock_t *lock, int pshared) 57{ 58 59 pthread__error(EINVAL, "Invalid pshared", 60 pshared == PTHREAD_PROCESS_PRIVATE || 61 pshared == PTHREAD_PROCESS_SHARED); 62 63 lock->pts_magic = _PT_SPINLOCK_MAGIC; 64 65 /* 66 * We don't actually use the pshared flag for anything; 67 * CPU simple locks have all the process-shared properties 68 * that we want anyway. 69 */ 70 lock->pts_flags = pshared; 71 pthread_lockinit(&lock->pts_spin); 72 73 return 0; 74} 75 76int 77pthread_spin_destroy(pthread_spinlock_t *lock) 78{ 79 80 pthread__error(EINVAL, "Invalid spinlock", 81 lock->pts_magic == _PT_SPINLOCK_MAGIC); 82 83 if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin)) 84 return EBUSY; 85 86 lock->pts_magic = _PT_SPINLOCK_DEAD; 87 88 return 0; 89} 90 91int 92pthread_spin_lock(pthread_spinlock_t *lock) 93{ 94 pthread_t self; 95 96 pthread__error(EINVAL, "Invalid spinlock", 97 lock->pts_magic == _PT_SPINLOCK_MAGIC); 98 99 self = pthread__self(); 100 while (pthread__spintrylock(self, &lock->pts_spin) == 0) { 101 pthread__smt_wait(); 102 } 103 104 return 0; 105} 106 107int 108pthread_spin_trylock(pthread_spinlock_t *lock) 109{ 110 pthread_t self; 111 112 pthread__error(EINVAL, "Invalid spinlock", 113 lock->pts_magic == _PT_SPINLOCK_MAGIC); 114 115 self = pthread__self(); 116 if (pthread__spintrylock(self, &lock->pts_spin) == 0) 117 return EBUSY; 118 return 0; 119} 120 121int 122pthread_spin_unlock(pthread_spinlock_t *lock) 123{ 124 pthread_t self; 125 126 pthread__error(EINVAL, "Invalid spinlock", 127 lock->pts_magic == _PT_SPINLOCK_MAGIC); 128 129 self = pthread__self(); 130 pthread__spinunlock(self, &lock->pts_spin); 131 pthread__smt_wake(); 132 133 return 0; 134} 135