1 /* $NetBSD: rwlock.h,v 1.4 2007/12/09 15:32:27 ad 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #ifndef _X86_RWLOCK_H_ 40 #define _X86_RWLOCK_H_ 41 42 struct krwlock { 43 volatile uintptr_t rw_owner; 44 }; 45 46 #ifdef __RWLOCK_PRIVATE 47 48 #define __HAVE_SIMPLE_RW_LOCKS 1 49 #define __HAVE_RW_STUBS 1 50 51 /* 52 * RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence. 53 */ 54 #define RW_RECEIVE(rw) /* nothing */ 55 56 /* 57 * RW_GIVE: no memory barrier required, as _lock_cas() will take care of it. 58 */ 59 #define RW_GIVE(rw) /* nothing */ 60 61 #define RW_CAS(p, o, n) \ 62 (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) 63 64 unsigned long _atomic_cas_ulong(volatile unsigned long *, 65 unsigned long, unsigned long); 66 67 #endif /* __RWLOCK_PRIVATE */ 68 69 #endif /* _X86_RWLOCK_H_ */ 70