141 lines
3.7 KiB
C
141 lines
3.7 KiB
C
/*-
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* Copyright (c) 2002, Jeffrey Roberson <jeff@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 unmodified, this list of conditions, and the following
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* 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 ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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*/
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#ifndef _SYS_UMTX_H_
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#define _SYS_UMTX_H_
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#include <sys/limits.h>
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/*
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* See pthread_*
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*/
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#define UMTX_UNOWNED 0x0
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#define UMTX_CONTESTED LONG_MIN
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struct umtx {
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void *u_owner; /* Owner of the mutex. */
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};
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/* op code for _umtx_op */
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#define UMTX_OP_LOCK 0
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#define UMTX_OP_UNLOCK 1
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#define UMTX_OP_WAIT 2
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#define UMTX_OP_WAKE 3
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#ifndef _KERNEL
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/*
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* System calls for acquiring and releasing contested mutexes.
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*/
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/* deprecated becaues it can only use thread id */
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int _umtx_lock(struct umtx *mtx);
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/* deprecated becaues it can only use thread id */
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int _umtx_unlock(struct umtx *mtx);
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int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr, void *uaddr2);
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/*
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* Standard api. Try uncontested acquire/release and asks the
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* kernel to resolve failures.
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*/
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static __inline void
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umtx_init(struct umtx *umtx)
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{
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umtx->u_owner = UMTX_UNOWNED;
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}
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static __inline long
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umtx_owner(struct umtx *umtx)
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{
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return ((long)umtx->u_owner & ~LONG_MIN);
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}
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static __inline int
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umtx_lock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
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(void *)id) == 0)
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if (_umtx_lock(umtx) == -1)
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return (errno);
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return (0);
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}
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static __inline int
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umtx_trylock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
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(void *)id) == 0)
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return (EBUSY);
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return (0);
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}
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static __inline int
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umtx_timedlock(struct umtx *umtx, long id, const struct timespec *timeout)
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{
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if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
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(void *)id) == 0)
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if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, (void *)timeout) == -1)
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return (errno);
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return (0);
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}
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static __inline int
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umtx_unlock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
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(void *)UMTX_UNOWNED) == 0)
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if (_umtx_unlock(umtx) == -1)
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return (errno);
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return (0);
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}
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static __inline int
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umtx_wait(struct umtx *umtx, long id, const struct timespec *timeout)
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{
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if (_umtx_op(umtx, UMTX_OP_WAIT, id, 0, (void *)timeout) == -1)
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return (errno);
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return (0);
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}
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/* Wake threads waiting on a user address. */
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static __inline int
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umtx_wake(struct umtx *umtx, int nr_wakeup)
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{
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if (_umtx_op(umtx, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
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return (errno);
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return (0);
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}
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#else
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struct umtx_q *umtxq_alloc(void);
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void umtxq_free(struct umtx_q *);
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#endif /* !_KERNEL */
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#endif /* !_SYS_UMTX_H_ */
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