135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
/* $NetBSD: pthread_spin.c,v 1.10 2022/04/10 10:38:33 riastradh Exp $ */
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/*-
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* Copyright (c) 2001, 2006, 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nathan J. Williams and Andrew Doran.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Public (POSIX-specified) spinlocks.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: pthread_spin.c,v 1.10 2022/04/10 10:38:33 riastradh Exp $");
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/* Need to use libc-private names for atomic operations. */
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#include "../../common/lib/libc/atomic/atomic_op_namespace.h"
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#include <sys/types.h>
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#include <sys/ras.h>
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#include <machine/lock.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "pthread.h"
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#include "pthread_int.h"
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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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pthread__error(EINVAL, "Invalid pshared",
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pshared == PTHREAD_PROCESS_PRIVATE ||
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pshared == PTHREAD_PROCESS_SHARED);
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lock->pts_magic = _PT_SPINLOCK_MAGIC;
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/*
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* We don't actually use the pshared flag for anything;
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* CPU simple locks have all the process-shared properties
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* that we want anyway.
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*/
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lock->pts_flags = pshared;
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pthread_lockinit(&lock->pts_spin);
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return 0;
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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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pthread__error(EINVAL, "Invalid spinlock",
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lock->pts_magic == _PT_SPINLOCK_MAGIC);
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if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin))
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return EBUSY;
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lock->pts_magic = _PT_SPINLOCK_DEAD;
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return 0;
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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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pthread_t self;
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pthread__error(EINVAL, "Invalid spinlock",
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lock->pts_magic == _PT_SPINLOCK_MAGIC);
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self = pthread__self();
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while (pthread__spintrylock(self, &lock->pts_spin) == 0) {
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pthread__smt_pause();
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}
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return 0;
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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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pthread_t self;
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pthread__error(EINVAL, "Invalid spinlock",
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lock->pts_magic == _PT_SPINLOCK_MAGIC);
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self = pthread__self();
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if (pthread__spintrylock(self, &lock->pts_spin) == 0)
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return EBUSY;
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return 0;
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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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pthread_t self;
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pthread__error(EINVAL, "Invalid spinlock",
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lock->pts_magic == _PT_SPINLOCK_MAGIC);
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self = pthread__self();
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pthread__spinunlock(self, &lock->pts_spin);
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pthread__smt_wake();
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return 0;
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}
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