lock.h revision 1.3.8.1
1 1.3.8.1 thorpej /* $NetBSD: lock.h,v 1.3.8.1 1999/08/02 20:09:13 thorpej Exp $ */ 2 1.1 pk 3 1.1 pk /*- 4 1.3.8.1 thorpej * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc. 5 1.1 pk * All rights reserved. 6 1.1 pk * 7 1.1 pk * This code is derived from software contributed to The NetBSD Foundation 8 1.1 pk * by Paul Kranenburg. 9 1.1 pk * 10 1.1 pk * Redistribution and use in source and binary forms, with or without 11 1.1 pk * modification, are permitted provided that the following conditions 12 1.1 pk * are met: 13 1.1 pk * 1. Redistributions of source code must retain the above copyright 14 1.1 pk * notice, this list of conditions and the following disclaimer. 15 1.1 pk * 2. Redistributions in binary form must reproduce the above copyright 16 1.1 pk * notice, this list of conditions and the following disclaimer in the 17 1.1 pk * documentation and/or other materials provided with the distribution. 18 1.1 pk * 3. All advertising materials mentioning features or use of this software 19 1.1 pk * must display the following acknowledgement: 20 1.1 pk * This product includes software developed by the NetBSD 21 1.1 pk * Foundation, Inc. and its contributors. 22 1.1 pk * 4. Neither the name of The NetBSD Foundation nor the names of its 23 1.1 pk * contributors may be used to endorse or promote products derived 24 1.1 pk * from this software without specific prior written permission. 25 1.1 pk * 26 1.1 pk * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 1.1 pk * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 1.1 pk * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 1.1 pk * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 1.1 pk * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 1.1 pk * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 1.1 pk * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 1.1 pk * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 1.1 pk * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 1.1 pk * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 1.1 pk * POSSIBILITY OF SUCH DAMAGE. 37 1.1 pk */ 38 1.1 pk 39 1.1 pk #ifndef _MACHINE_LOCK_H 40 1.1 pk #define _MACHINE_LOCK_H 41 1.1 pk 42 1.1 pk /* 43 1.1 pk * Machine dependent spin lock operations. 44 1.1 pk */ 45 1.1 pk 46 1.1 pk #if defined(_KERNEL) 47 1.1 pk 48 1.1 pk #include <sparc/sparc/asm.h> 49 1.1 pk 50 1.3.8.1 thorpej /* 51 1.3.8.1 thorpej * The value for SIMPLELOCK_LOCKED is what ldstub() naturally stores 52 1.3.8.1 thorpej * `lock_data' given its address (and the fact that SPARC is big-endian). 53 1.3.8.1 thorpej */ 54 1.3.8.1 thorpej #undef SIMPLELOCK_LOCKED 55 1.3.8.1 thorpej #define SIMPLELOCK_LOCKED 0xff000000 56 1.3.8.1 thorpej 57 1.3.8.1 thorpej static void cpu_simple_lock_init __P((__volatile struct simplelock *)); 58 1.3.8.1 thorpej static void cpu_simple_lock __P((__volatile struct simplelock *)); 59 1.3.8.1 thorpej static int cpu_simple_lock_try __P((__volatile struct simplelock *)); 60 1.3.8.1 thorpej static void cpu_simple_unlock __P((__volatile struct simplelock *)); 61 1.1 pk 62 1.1 pk static __inline__ void 63 1.3.8.1 thorpej cpu_simple_lock_init (alp) 64 1.1 pk __volatile struct simplelock *alp; 65 1.1 pk { 66 1.2 pk 67 1.3.8.1 thorpej alp->lock_data = SIMPLELOCK_UNLOCKED; 68 1.1 pk } 69 1.1 pk 70 1.1 pk static __inline__ void 71 1.3.8.1 thorpej cpu_simple_lock (alp) 72 1.1 pk __volatile struct simplelock *alp; 73 1.1 pk { 74 1.2 pk 75 1.2 pk /* 76 1.2 pk * If someone else holds the lock use simple 77 1.2 pk * reads until it is released, then retry the 78 1.2 pk * atomic operation. This reduces memory bus contention 79 1.2 pk * becaused the cache-coherency logic does not have to 80 1.2 pk * broadcast invalidates on the lock while we spin on it. 81 1.2 pk */ 82 1.3.8.1 thorpej while (ldstub(&alp->lock_data) != SIMPLELOCK_UNLOCKED) { 83 1.3.8.1 thorpej while (alp->lock_data != SIMPLELOCK_UNLOCKED) 84 1.2 pk /*void*/; 85 1.2 pk } 86 1.1 pk } 87 1.1 pk 88 1.1 pk static __inline__ int 89 1.3.8.1 thorpej cpu_simple_lock_try (alp) 90 1.1 pk __volatile struct simplelock *alp; 91 1.1 pk { 92 1.2 pk 93 1.3.8.1 thorpej return (ldstub(&alp->lock_data) == SIMPLELOCK_UNLOCKED); 94 1.1 pk } 95 1.1 pk 96 1.1 pk static __inline__ void 97 1.3.8.1 thorpej cpu_simple_unlock (alp) 98 1.1 pk __volatile struct simplelock *alp; 99 1.1 pk { 100 1.2 pk 101 1.3.8.1 thorpej alp->lock_data = SIMPLELOCK_UNLOCKED; 102 1.1 pk } 103 1.3 chs 104 1.1 pk #endif /* _KERNEL */ 105 1.1 pk 106 1.1 pk #endif /* _MACHINE_LOCK_H */ 107
Indexes created Tue Oct 14 11:09:46 GMT 2025