minix/sys/arch/x86/include/rwlock.h

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/* $NetBSD: rwlock.h,v 1.5 2008/04/28 20:23:40 martin Exp $ */
/*-
* Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe and Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _X86_RWLOCK_H_
#define _X86_RWLOCK_H_
struct krwlock {
volatile uintptr_t rw_owner;
};
#ifdef __RWLOCK_PRIVATE
#define __HAVE_SIMPLE_RW_LOCKS 1
#define __HAVE_RW_STUBS 1
/*
* RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence.
*/
#define RW_RECEIVE(rw) /* nothing */
/*
* RW_GIVE: no memory barrier required, as _lock_cas() will take care of it.
*/
#define RW_GIVE(rw) /* nothing */
#define RW_CAS(p, o, n) \
(_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
unsigned long _atomic_cas_ulong(volatile unsigned long *,
unsigned long, unsigned long);
#endif /* __RWLOCK_PRIVATE */
#endif /* _X86_RWLOCK_H_ */