1 /* $NetBSD: rwlock.h,v 1.5 2008/04/28 20:23:40 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe and Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _X86_RWLOCK_H_ 33 #define _X86_RWLOCK_H_ 34 35 struct krwlock { 36 volatile uintptr_t rw_owner; 37 }; 38 39 #ifdef __RWLOCK_PRIVATE 40 41 #define __HAVE_SIMPLE_RW_LOCKS 1 42 #define __HAVE_RW_STUBS 1 43 44 /* 45 * RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence. 46 */ 47 #define RW_RECEIVE(rw) /* nothing */ 48 49 /* 50 * RW_GIVE: no memory barrier required, as _lock_cas() will take care of it. 51 */ 52 #define RW_GIVE(rw) /* nothing */ 53 54 #define RW_CAS(p, o, n) \ 55 (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) 56 57 unsigned long _atomic_cas_ulong(volatile unsigned long *, 58 unsigned long, unsigned long); 59 60 #endif /* __RWLOCK_PRIVATE */ 61 62 #endif /* _X86_RWLOCK_H_ */ 63