23ec020060
threads can wait for a thread to exit, and safely assume that the thread has left userland and is no longer using its userland stack, this is necessary for pthread_join when a thread is waiting for another thread to exit which has user customized stack, after pthread_join returns, the userland stack can be reused for other purposes, without this change, the joiner thread has to spin at the address to ensure the thread is really exited.
143 lines
3.7 KiB
C
143 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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struct thread;
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int kern_umtx_wake(struct thread *td, void *uaddr, int n_wake);
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#endif /* !_KERNEL */
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#endif /* !_SYS_UMTX_H_ */
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