root / lab4 / .minix-src / include / sys / common_lock.h @ 13
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| 1 | 13 | up20180614 | /* $NetBSD: common_lock.h,v 1.1 2015/06/26 14:27:35 matt Exp $ */
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| 2 | |||
| 3 | /*-
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| 4 | * Copyright (c) 2014 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 Matt Thomas of 3am Software Foundry.
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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 | /*
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| 33 | * Machine-dependent spin lock operations using the builtin compiler atomic
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| 34 | * primitives.
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| 35 | */
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| 36 | |||
| 37 | #ifndef _SYS_COMMON_LOCK_H_
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| 38 | #define _SYS_COMMON_LOCK_H_
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| 39 | |||
| 40 | static __inline int |
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| 41 | __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr) |
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| 42 | {
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| 43 | return *__ptr != __SIMPLELOCK_UNLOCKED;
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| 44 | } |
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| 45 | |||
| 46 | static __inline int |
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| 47 | __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr) |
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| 48 | {
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| 49 | return *__ptr == __SIMPLELOCK_UNLOCKED;
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| 50 | } |
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| 51 | |||
| 52 | static __inline void |
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| 53 | __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr) |
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| 54 | {
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| 55 | #if 1 |
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| 56 | *__ptr = __SIMPLELOCK_UNLOCKED; |
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| 57 | #else
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| 58 | __atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED); |
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| 59 | #endif
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| 60 | } |
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| 61 | |||
| 62 | static __inline void |
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| 63 | __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr) |
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| 64 | {
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| 65 | #if 1 |
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| 66 | *__ptr = __SIMPLELOCK_LOCKED; |
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| 67 | #else
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| 68 | __atomic_store_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_RELAXED); |
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| 69 | #endif
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| 70 | } |
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| 71 | |||
| 72 | static __inline void __unused |
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| 73 | __cpu_simple_lock_init(__cpu_simple_lock_t *__ptr) |
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| 74 | {
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| 75 | #if 1 |
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| 76 | *__ptr = __SIMPLELOCK_UNLOCKED; |
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| 77 | #else
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| 78 | __atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED); |
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| 79 | #endif
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| 80 | } |
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| 81 | |||
| 82 | static __inline void __unused |
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| 83 | __cpu_simple_lock(__cpu_simple_lock_t *__ptr) |
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| 84 | {
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| 85 | while (__atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_LOCKED) {
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| 86 | /* do nothing */
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| 87 | } |
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| 88 | } |
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| 89 | |||
| 90 | static __inline int __unused |
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| 91 | __cpu_simple_lock_try(__cpu_simple_lock_t *__ptr) |
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| 92 | {
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| 93 | return __atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_UNLOCKED;
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| 94 | } |
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| 95 | |||
| 96 | static __inline void __unused |
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| 97 | __cpu_simple_unlock(__cpu_simple_lock_t *__ptr) |
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| 98 | {
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| 99 | __atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELEASE); |
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| 100 | } |
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| 101 | |||
| 102 | #endif /* _SYS_COMMON_LOCK_H_ */ |