rwlock.h revision 1.2 
1/*	$NetBSD: rwlock.h,v 1.2 2008/03/20 14:56:06 kochi Exp $	*/
2
3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Takayoshi Kochi.
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 _IA64_RWLOCK_H_
40#define	_IA64_RWLOCK_H_
41
42#include <sys/atomic.h>
43
44struct krwlock {
45	volatile uintptr_t	rw_owner;
46};
47
48#ifdef __RWLOCK_PRIVATE
49
50#define	__HAVE_SIMPLE_RW_LOCKS		1
51/* #define	__HAVE_RW_STUBS			1 */
52
53/*
54 * RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence.
55 */
56#define	RW_RECEIVE(rw)			/* nothing */
57
58/*
59 * RW_GIVE: no memory barrier required, as _lock_cas() will take care of it.
60 */
61#define	RW_GIVE(rw)			/* nothing */
62
63#define	RW_CAS(p, o, n)			\
64    (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
65
66#endif	/* __RWLOCK_PRIVATE */
67
68#endif /* _IA64_RWLOCK_H_ */
69