mutex.h revision 1.1.2.3
1 /* $NetBSD: mutex.h,v 1.1.2.3 2007/02/01 05:36:20 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe and Andrew Doran. 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #ifndef _HPPA_MUTEX_H_ 40 #define _HPPA_MUTEX_H_ 41 42 /* 43 * The HPPA mutex implementation is troublesome, because HPPA lacks 44 * a compare-and-set operation, yet there are many SMP HPPA machines 45 * in circulation. SMP for spin mutexes is easy - we don't need to 46 * know who owns the lock. For adaptive mutexes, we need an owner 47 * field and additional interlock 48 */ 49 struct kmutex { 50 union { 51 /* 52 * Only the low 4 bytes of the lock will be used by 53 * __cpu_simple_lock(), but it must be aligned on a 54 * 16-byte boundary. See hppa/lock.h 55 */ 56 #ifdef __MUTEX_PRIVATE 57 __cpu_simple_lock_t mtxu_lock; /* 0-15 */ 58 struct { 59 volatile uint32_t mtxs_lockword; /* 0-3 */ 60 volatile uint32_t mtxs_owner; /* 4-7 */ 61 ipl_cookie_t mtxs_ipl; /* 8-11 */ 62 volatile uint8_t mtxs_waiters; /* 12 */ 63 64 /* For LOCKDEBUG */ 65 uint8_t mtxs_id[3]; /* 13-15 */ 66 } s; 67 #endif 68 uint8_t mtxu_pad[16]; /* 0-15 */ 69 } u; 70 } __aligned (16); 71 72 #ifdef __MUTEX_PRIVATE 73 74 #define __HAVE_MUTEX_STUBS 1 75 76 #define mtx_lock u.mtxu_lock 77 #define mtx_owner u.s.mtxs_owner 78 #define mtx_ipl u.s.mtxs_ipl 79 #define mtx_waiters u.s.mtxs_waiters 80 #define mtx_id u.s.mtxs_id 81 82 /* Magic constants for mtx_owner */ 83 #define MUTEX_ADAPTIVE_UNOWNED 0xffffff00 84 #define MUTEX_SPIN_FLAG 0xffffff10 85 #define MUTEX_UNOWNED_OR_SPIN(x) (((x) & 0xffffffef) == 0xffffff0f) 86 87 static uintptr_t __attribute((unused)) 88 MUTEX_OWNER(uintptr_t owner) 89 { 90 return owner; 91 } 92 93 static int __attribute((unused)) 94 MUTEX_OWNED(uintptr_t owner) 95 { 96 return owner != MUTEX_ADAPTIVE_UNOWNED; 97 } 98 99 static inline int 100 MUTEX_SET_WAITERS(kmutex_t *mtx, uintptr_t owner) 101 { 102 mb_write(); 103 mtx->mtx_waiters = 1; 104 mb_memory(); 105 return mtx->mtx_owner != MUTEX_ADAPTIVE_UNOWNED; 106 } 107 108 static inline int 109 MUTEX_HAS_WAITERS(volatile kmutex_t *mtx) 110 { 111 return mtx->mtx_waiters != 0; 112 } 113 114 static inline void 115 MUTEX_INITIALIZE_SPIN(kmutex_t *mtx, u_int id, int ipl) 116 { 117 mtx->mtx_ipl = makeiplcookie(ipl); 118 mtx->mtx_id[0] = (uint8_t)id; 119 mtx->mtx_id[1] = (uint8_t)(id >> 8); 120 mtx->mtx_id[2] = (uint8_t)(id >> 16); 121 mtx->mtx_owner = MUTEX_SPIN_FLAG; 122 __cpu_simple_lock_init(&mtx->mtx_lock); 123 } 124 125 static inline void 126 MUTEX_INITIALIZE_ADAPTIVE(kmutex_t *mtx, u_int id) 127 { 128 mtx->mtx_id[0] = (uint8_t)id; 129 mtx->mtx_id[1] = (uint8_t)(id >> 8); 130 mtx->mtx_id[2] = (uint8_t)(id >> 16); 131 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 132 __cpu_simple_lock_init(&mtx->mtx_lock); 133 } 134 135 static inline void 136 MUTEX_DESTROY(kmutex_t *mtx) 137 { 138 mtx->mtx_waiters = 1; 139 mtx->mtx_id[0] = 0xff; 140 mtx->mtx_id[1] = 0xff; 141 mtx->mtx_id[2] = 0xff; 142 } 143 144 static inline u_int 145 MUTEX_GETID(kmutex_t *mtx) 146 { 147 return (u_int)mtx->mtx_id[0] | 148 ((u_int)mtx->mtx_id[1] << 8) | 149 ((u_int)mtx->mtx_id[2] << 16); 150 } 151 152 static inline int 153 MUTEX_SPIN_P(volatile kmutex_t *mtx) 154 { 155 return mtx->mtx_owner == MUTEX_SPIN_FLAG; 156 } 157 158 static inline int 159 MUTEX_ADAPTIVE_P(volatile kmutex_t *mtx) 160 { 161 return mtx->mtx_owner != MUTEX_SPIN_FLAG; 162 } 163 164 /* Acquire an adaptive mutex */ 165 static inline int 166 MUTEX_ACQUIRE(kmutex_t *mtx, uintptr_t curthread) 167 { 168 if (!__cpu_simple_lock_try(&mtx->mtx_lock)) 169 return 0; 170 mtx->mtx_owner = curthread; 171 return 1; 172 } 173 174 /* Release an adaptive mutex */ 175 static inline void 176 MUTEX_RELEASE(kmutex_t *mtx) 177 { 178 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 179 __cpu_simple_unlock(&mtx->mtx_lock); 180 mtx->mtx_waiters = 0; 181 } 182 183 #endif /* __MUTEX_PRIVATE */ 184 185 #endif /* _HPPA_MUTEX_H_ */ 186
Indexes created Thu Oct 02 14:10:14 GMT 2025