mutex.h revision 1.18
1 /* $NetBSD: mutex.h,v 1.18 2023/07/12 12:50:12 riastradh 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 * 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 _HPPA_MUTEX_H_ 33 #define _HPPA_MUTEX_H_ 34 35 /* 36 * The HPPA mutex implementation is troublesome, because HPPA lacks 37 * a compare-and-set operation, yet there are many SMP HPPA machines 38 * in circulation. SMP for spin mutexes is easy - we don't need to 39 * know who owns the lock. For adaptive mutexes, we need an owner 40 * field and additional interlock 41 */ 42 43 #ifndef __ASSEMBLER__ 44 45 #include <sys/types.h> 46 47 #ifdef __MUTEX_PRIVATE 48 #include <machine/intr.h> 49 #endif 50 51 struct kmutex { 52 union { 53 /* 54 * Only the 16 bytes aligned word of __cpu_simple_lock_t will 55 * be used. It's 16 bytes to simplify the allocation. 56 * See hppa/lock.h 57 */ 58 #ifdef __MUTEX_PRIVATE 59 struct { 60 __cpu_simple_lock_t mtxu_lock; /* 0-15 */ 61 volatile uint32_t mtxs_owner; /* 16-19 */ 62 ipl_cookie_t mtxs_ipl; /* 20-23 */ 63 volatile uint8_t mtxs_waiters; /* 24 */ 64 65 /* For LOCKDEBUG */ 66 uint8_t mtxs_dodebug; /* 25 */ 67 } s; 68 #endif 69 uint8_t mtxu_pad[32]; /* 0 - 32 */ 70 } u; 71 } __aligned (16); 72 #endif 73 74 #ifdef __MUTEX_PRIVATE 75 76 #define __HAVE_MUTEX_STUBS 1 77 78 #define mtx_lock u.s.mtxu_lock 79 #define mtx_owner u.s.mtxs_owner 80 #define mtx_ipl u.s.mtxs_ipl 81 #define mtx_waiters u.s.mtxs_waiters 82 #define mtx_dodebug u.s.mtxs_dodebug 83 84 /* Magic constants for mtx_owner */ 85 #define MUTEX_ADAPTIVE_UNOWNED 0xffffff00 86 #define MUTEX_SPIN_FLAG 0xffffff10 87 #define MUTEX_UNOWNED_OR_SPIN(x) (((x) & 0xffffffef) == 0xffffff00) 88 89 #if !defined(__ASSEMBLER__) && defined(_KERNEL) 90 91 static inline uintptr_t 92 MUTEX_OWNER(uintptr_t owner) 93 { 94 return owner; 95 } 96 97 static inline int 98 MUTEX_OWNED(uintptr_t owner) 99 { 100 return owner != MUTEX_ADAPTIVE_UNOWNED; 101 } 102 103 static inline int 104 MUTEX_SET_WAITERS(struct kmutex *mtx, uintptr_t owner) 105 { 106 __sync(); /* formerly mb_read */ 107 mtx->mtx_waiters = 1; 108 __sync(); /* formerly mb_memory */ 109 return mtx->mtx_owner != MUTEX_ADAPTIVE_UNOWNED; 110 } 111 112 static inline int 113 MUTEX_HAS_WAITERS(const volatile struct kmutex *mtx) 114 { 115 return mtx->mtx_waiters != 0; 116 } 117 118 static inline void 119 MUTEX_INITIALIZE_SPIN(struct kmutex *mtx, bool dodebug, int ipl) 120 { 121 mtx->mtx_ipl = makeiplcookie(ipl); 122 mtx->mtx_dodebug = dodebug; 123 mtx->mtx_owner = MUTEX_SPIN_FLAG; 124 __cpu_simple_lock_init(&mtx->mtx_lock); 125 } 126 127 static inline void 128 MUTEX_INITIALIZE_ADAPTIVE(struct kmutex *mtx, bool dodebug) 129 { 130 mtx->mtx_dodebug = dodebug; 131 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 132 __cpu_simple_lock_init(&mtx->mtx_lock); 133 } 134 135 static inline void 136 MUTEX_DESTROY(struct kmutex *mtx) 137 { 138 mtx->mtx_owner = 0xffffffff; 139 } 140 141 static inline bool 142 MUTEX_DEBUG_P(const volatile struct kmutex *mtx) 143 { 144 return mtx->mtx_dodebug != 0; 145 } 146 147 static inline int 148 MUTEX_SPIN_P(const uintptr_t owner) 149 { 150 return owner == MUTEX_SPIN_FLAG; 151 } 152 153 static inline int 154 MUTEX_ADAPTIVE_P(const uintptr_t owner) 155 { 156 return owner != MUTEX_SPIN_FLAG; 157 } 158 159 /* Acquire an adaptive mutex */ 160 static inline int 161 MUTEX_ACQUIRE(struct kmutex *mtx, uintptr_t curthread) 162 { 163 if (!__cpu_simple_lock_try(&mtx->mtx_lock)) 164 return 0; 165 mtx->mtx_owner = curthread; 166 return 1; 167 } 168 169 /* Release an adaptive mutex */ 170 static inline void 171 MUTEX_RELEASE(struct kmutex *mtx) 172 { 173 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED; 174 __cpu_simple_unlock(&mtx->mtx_lock); 175 mtx->mtx_waiters = 0; 176 } 177 178 static inline void 179 MUTEX_CLEAR_WAITERS(struct kmutex *mtx) 180 { 181 mtx->mtx_waiters = 0; 182 } 183 184 #endif /* !__ASSEMBLER__ && _KERNEL */ 185 186 #endif /* __MUTEX_PRIVATE */ 187 188 #endif /* _HPPA_MUTEX_H_ */ 189
Indexes created Tue Sep 30 20:09:53 GMT 2025