62 lines
2.2 KiB
C
62 lines
2.2 KiB
C
/* $NetBSD: rwlock.h,v 1.3 2008/04/28 20:23:39 martin Exp $ */
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/*-
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* Copyright (c) 2002, 2006 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 Jason R. Thorpe 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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#ifndef _ARCH_USERMODE_INCLUDE_RWLOCK_H_
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#define _ARCH_USERMODE_INCLUDE_RWLOCK_H_
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struct krwlock {
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volatile uintptr_t rw_owner;
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};
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#ifdef __RWLOCK_PRIVATE
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#define __HAVE_SIMPLE_RW_LOCKS 1
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/*
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* RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence.
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*/
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#define RW_RECEIVE(rw) /* nothing */
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/*
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* RW_GIVE: no memory barrier required, as _lock_cas() will take care of it.
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*/
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#define RW_GIVE(rw) /* nothing */
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#define RW_CAS(p, o, n) \
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(_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
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unsigned long _atomic_cas_ulong(volatile unsigned long *,
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unsigned long, unsigned long);
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#endif /* __RWLOCK_PRIVATE */
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#endif /* _ARCH_USERMODE_INCLUDE_RWLOCK_H_ */
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