root / lab4 / .minix-src / include / x86 / rwlock.h @ 14
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| 1 | 13 | up20180614 | /* $NetBSD: rwlock.h,v 1.5 2008/04/28 20:23:40 martin Exp $ */
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| 2 | |||
| 3 | /*-
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| 4 | * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.
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| 5 | * All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to The NetBSD Foundation
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| 8 | * by Jason R. Thorpe and Andrew Doran.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | *
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| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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| 29 | * POSSIBILITY OF SUCH DAMAGE.
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| 30 | */
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| 31 | |||
| 32 | #ifndef _X86_RWLOCK_H_
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| 33 | #define _X86_RWLOCK_H_
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| 34 | |||
| 35 | struct krwlock {
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| 36 | volatile uintptr_t rw_owner;
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| 37 | }; |
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| 38 | |||
| 39 | #ifdef __RWLOCK_PRIVATE
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| 40 | |||
| 41 | #define __HAVE_SIMPLE_RW_LOCKS 1 |
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| 42 | #define __HAVE_RW_STUBS 1 |
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| 43 | |||
| 44 | /*
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| 45 | * RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence.
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| 46 | */
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| 47 | #define RW_RECEIVE(rw) /* nothing */ |
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| 48 | |||
| 49 | /*
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| 50 | * RW_GIVE: no memory barrier required, as _lock_cas() will take care of it.
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| 51 | */
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| 52 | #define RW_GIVE(rw) /* nothing */ |
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| 53 | |||
| 54 | #define RW_CAS(p, o, n) \
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| 55 | (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) |
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| 56 | |||
| 57 | unsigned long _atomic_cas_ulong(volatile unsigned long *, |
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| 58 | unsigned long, unsigned long); |
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| 59 | |||
| 60 | #endif /* __RWLOCK_PRIVATE */ |
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| 61 | |||
| 62 | #endif /* _X86_RWLOCK_H_ */ |