1 /* $NetBSD: spinlock.h,v 1.6 2015/01/01 01:15:42 mrg Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 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 * 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. 30 */ 31 32 #ifndef _LINUX_SPINLOCK_H_ 33 #define _LINUX_SPINLOCK_H_ 34 35 #include <sys/cdefs.h> 36 #include <sys/mutex.h> 37 38 #define __acquires(lock) /* XXX lockdep stuff */ 39 #define __releases(lock) /* XXX lockdep stuff */ 40 41 typedef struct spinlock { 42 kmutex_t sl_lock; 43 } spinlock_t; 44 45 static inline int 46 spin_is_locked(spinlock_t *spinlock) 47 { 48 return mutex_owned(&spinlock->sl_lock); 49 } 50 51 static inline void 52 spin_lock(spinlock_t *spinlock) 53 { 54 mutex_enter(&spinlock->sl_lock); 55 } 56 57 static inline void 58 spin_unlock(spinlock_t *spinlock) 59 { 60 mutex_exit(&spinlock->sl_lock); 61 } 62 63 static inline void 64 spin_lock_irq(spinlock_t *spinlock) 65 { 66 spin_lock(spinlock); 67 } 68 69 static inline void 70 spin_unlock_irq(spinlock_t *spinlock) 71 { 72 spin_unlock(spinlock); 73 } 74 75 /* Must be a macro because the second argument is to be assigned. */ 76 #define spin_lock_irqsave(SPINLOCK, FLAGS) \ 77 do { \ 78 (FLAGS) = 0; \ 79 mutex_enter(&((spinlock_t *)(SPINLOCK))->sl_lock); \ 80 } while (0) 81 82 static inline void 83 spin_unlock_irqrestore(spinlock_t *spinlock, unsigned long __unused flags) 84 { 85 mutex_exit(&spinlock->sl_lock); 86 } 87 88 static inline void 89 spin_lock_init(spinlock_t *spinlock) 90 { 91 /* XXX What's the right IPL? IPL_DRM...? */ 92 mutex_init(&spinlock->sl_lock, MUTEX_DEFAULT, IPL_VM); 93 } 94 95 /* 96 * XXX Linux doesn't ever destroy spin locks, it seems. We'll have to 97 * kludge it up. 98 */ 99 100 static inline void 101 spin_lock_destroy(spinlock_t *spinlock) 102 { 103 mutex_destroy(&spinlock->sl_lock); 104 } 105 106 /* This is a macro to make the panic message clearer. */ 107 #define assert_spin_locked(spinlock) \ 108 KASSERT(mutex_owned(&(spinlock)->sl_lock)) 109 110 /* 111 * Linux rwlocks are reader/writer spin locks. We implement them as 112 * normal spin locks without reader/writer semantics for expedience. 113 * If that turns out to not work, adapting to reader/writer semantics 114 * shouldn't be too hard. 115 */ 116 117 #define rwlock_t spinlock_t 118 #define rwlock_init spin_lock_init 119 #define rwlock_destroy spin_lock_destroy 120 #define write_lock_irq spin_lock_irq 121 #define write_unlock_irq spin_unlock_irq 122 #define read_lock spin_lock 123 #define read_unlock spin_unlock 124 125 #endif /* _LINUX_SPINLOCK_H_ */ 126