1 /* $NetBSD: rwlock.h,v 1.9 2015/02/25 13:52:42 joerg Exp $ */
4 * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe and Andrew Doran.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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.
32 #ifndef _ARM_RWLOCK_H_
33 #define _ARM_RWLOCK_H_
36 volatile uintptr_t rw_owner
;
39 #ifdef __RWLOCK_PRIVATE
41 #define __HAVE_SIMPLE_RW_LOCKS 1
45 #define RW_RECEIVE(rw) __asm __volatile("dmb" ::: "memory")
46 #define RW_GIVE(rw) __asm __volatile("dsb" ::: "memory")
48 #define RW_RECEIVE(rw) membar_consumer()
49 #define RW_GIVE(rw) membar_producer()
52 #define RW_RECEIVE(rw) /* nothing */
53 #define RW_GIVE(rw) /* nothing */
56 #define RW_CAS(p, o, n) \
57 (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
59 #endif /* __RWLOCK_PRIVATE */
61 #endif /* _ARM_RWLOCK_H_ */