mutex.h revision 1.1.2.1
1 /* $NetBSD: mutex.h,v 1.1.2.1 2007/01/29 14:34:10 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 __cpu_simple_lock_t mtxu_lock; /* 0-15 */ 57 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 } u; 68 } __aligned (16); 69 70 #ifdef __MUTEX_PRIVATE 71 72 #define __HAVE_MUTEX_STUBS 1 73 74 #define mtx_lock u.mtxu_lock 75 #define mtx_owner u.s.mtxs_owner 76 #define mtx_ipl u.s.mtxs_ipl 77 #define mtx_waiters u.s.mtxs_waiters 78 #define mtx_id u.s.mtxs_id 79 80 /* Magic constants for mtx_owner */ 81 #define MUTEX_ADAPTIVE_UNOWNED 0xfffffff0 82 #define MUTEX_SPIN_FLAG 0xffffffff 83 #define MUTEX_UNOWNED_OR_SPIN(x) (((x) & 0xfffffff0) == 0xfffffff0) 84 85 static uintptr_t __attribute((unused)) 86 MUTEX_OWNER(uintptr_t owner) 87 { 88 return owner; 89 } 90 91 static inline int 92 MUTEX_SET_WAITERS(kmutex_t *mtx, uintptr_t owner) 93 { 94 mb_write(); 95 mtx->mtx_waiters = 1; 96 mb_memory(); 97 return mtx->mtx_owner != MUTEX_ADAPTIVE_UNOWNED; 98 } 99 100 static inline int 101 MUTEX_HAS_WAITERS(volatile kmutex_t *mtx) 102 { 103 return mtx->mtx_waiters != 0; 104 } 105 106 static inline void 107 MUTEX_INITIALIZE_SPIN(kmutex_t *mtx, u_int id, int ipl) 108 { 109 mtx->mtx_ipl = makeiplcookie(ipl); 110 mtx->mtx_id[0] = (uint8_t)id; 111 mtx->mtx_id[1] = (uint8_t)(id >> 8); 112 mtx->mtx_id[2] = (uint8_t)(id >> 16); 113 mtx->mtx_owner = MUTEX_SPIN_FLAG; 114 __cpu_simple_lock_init(&mtx->mtx_lock); 115 } 116 117 static inline void 118 MUTEX_INITIALIZE_ADAPTIVE(kmutex_t *mtx, u_int id) 119 { 120 mtx->mtx_id[0] = (uint8_t)id; 121 mtx->mtx_id[1] = (uint8_t)(id >> 8); 122 mtx->mtx_id[2] = (uint8_t)(id >> 16); 123 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 124 __cpu_simple_lock_init(&mtx->mtx_lock); 125 } 126 127 static inline void 128 MUTEX_DESTROY(kmutex_t *mtx) 129 { 130 mtx->mtx_waiters = 1; 131 mtx->mtx_id[0] = 0xff; 132 mtx->mtx_id[1] = 0xff; 133 mtx->mtx_id[2] = 0xff; 134 } 135 136 static inline u_int 137 MUTEX_GETID(kmutex_t *mtx) 138 { 139 return (u_int)mtx->mtx_id[0] | 140 ((u_int)mtx->mtx_id[1] << 8) | 141 ((u_int)mtx->mtx_id[2] << 16); 142 } 143 144 static inline int 145 MUTEX_SPIN_P(volatile kmutex_t *mtx) 146 { 147 return mtx->mtx_owner == MUTEX_SPIN_FLAG; 148 } 149 150 static inline int 151 MUTEX_ADAPTIVE_P(volatile kmutex_t *mtx) 152 { 153 return mtx->mtx_owner != MUTEX_SPIN_FLAG; 154 } 155 156 /* Acquire an adaptive mutex */ 157 static inline int 158 MUTEX_ACQUIRE(kmutex_t *mtx, uintptr_t curthread) 159 { 160 if (!__cpu_simple_lock_try(&mtx->mtx_lock)) 161 return 0; 162 mtx->mtx_owner = curthread; 163 return 1; 164 } 165 166 /* Release an adaptive mutex */ 167 static inline void 168 MUTEX_RELEASE(kmutex_t *mtx) 169 { 170 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 171 __cpu_simple_unlock(&mtx->mtx_lock); 172 mtx->mtx_waiters = 0; 173 } 174 175 #endif /* __MUTEX_PRIVATE */ 176 177 #endif /* _HPPA_MUTEX_H_ */ 178
Indexes created Fri Oct 03 02:09:57 GMT 2025