projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| b688fc87 WJ |
1 | /* |
| 2 | * Copyright (c) 1991 Regents of the University of California. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * The Mach Operating System project at Carnegie-Mellon University. | |
| 7 | * | |
| 8 | * Redistribution and use in source and binary forms, with or without | |
| 9 | * modification, are permitted provided that the following conditions | |
| 10 | * are met: | |
| 11 | * 1. Redistributions of source code must retain the above copyright | |
| 12 | * notice, this list of conditions and the following disclaimer. | |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright | |
| 14 | * notice, this list of conditions and the following disclaimer in the | |
| 15 | * documentation and/or other materials provided with the distribution. | |
| 16 | * 3. All advertising materials mentioning features or use of this software | |
| 17 | * must display the following acknowledgement: | |
| 18 | * This product includes software developed by the University of | |
| 19 | * California, Berkeley and its contributors. | |
| 20 | * 4. Neither the name of the University nor the names of its contributors | |
| 21 | * may be used to endorse or promote products derived from this software | |
| 22 | * without specific prior written permission. | |
| 23 | * | |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 34 | * SUCH DAMAGE. | |
| 35 | * | |
| 36 | * @(#)lock.h 7.3 (Berkeley) 4/21/91 | |
| 37 | * | |
| 38 | * | |
| 39 | * Copyright (c) 1987, 1990 Carnegie-Mellon University. | |
| 40 | * All rights reserved. | |
| 41 | * | |
| 42 | * Authors: Avadis Tevanian, Jr., Michael Wayne Young | |
| 43 | * | |
| 44 | * Permission to use, copy, modify and distribute this software and | |
| 45 | * its documentation is hereby granted, provided that both the copyright | |
| 46 | * notice and this permission notice appear in all copies of the | |
| 47 | * software, derivative works or modified versions, and any portions | |
| 48 | * thereof, and that both notices appear in supporting documentation. | |
| 49 | * | |
| 50 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
| 51 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND | |
| 52 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
| 53 | * | |
| 54 | * Carnegie Mellon requests users of this software to return to | |
| 55 | * | |
| 56 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
| 57 | * School of Computer Science | |
| 58 | * Carnegie Mellon University | |
| 59 | * Pittsburgh PA 15213-3890 | |
| 60 | * | |
| 61 | * any improvements or extensions that they make and grant Carnegie the | |
| 62 | * rights to redistribute these changes. | |
| 63 | */ | |
| 64 | ||
| 65 | /* | |
| 66 | * Locking primitives definitions | |
| 67 | */ | |
| 68 | ||
| 69 | #ifndef _LOCK_H_ | |
| 70 | #define _LOCK_H_ | |
| 71 | ||
| 72 | #define NCPUS 1 /* XXX */ | |
| 73 | ||
| 74 | /* | |
| 75 | * A simple spin lock. | |
| 76 | */ | |
| 77 | ||
| 78 | struct slock { | |
| 79 | int lock_data; /* in general 1 bit is sufficient */ | |
| 80 | }; | |
| 81 | ||
| 82 | typedef struct slock simple_lock_data_t; | |
| 83 | typedef struct slock *simple_lock_t; | |
| 84 | ||
| 85 | /* | |
| 86 | * The general lock structure. Provides for multiple readers, | |
| 87 | * upgrading from read to write, and sleeping until the lock | |
| 88 | * can be gained. | |
| 89 | */ | |
| 90 | ||
| 91 | struct lock { | |
| 92 | #ifdef vax | |
| 93 | /* | |
| 94 | * Efficient VAX implementation -- see field description below. | |
| 95 | */ | |
| 96 | unsigned int read_count:16, | |
| 97 | want_upgrade:1, | |
| 98 | want_write:1, | |
| 99 | waiting:1, | |
| 100 | can_sleep:1, | |
| 101 | :0; | |
| 102 | ||
| 103 | simple_lock_data_t interlock; | |
| 104 | #else vax | |
| 105 | #ifdef ns32000 | |
| 106 | /* | |
| 107 | * Efficient ns32000 implementation -- | |
| 108 | * see field description below. | |
| 109 | */ | |
| 110 | simple_lock_data_t interlock; | |
| 111 | unsigned int read_count:16, | |
| 112 | want_upgrade:1, | |
| 113 | want_write:1, | |
| 114 | waiting:1, | |
| 115 | can_sleep:1, | |
| 116 | :0; | |
| 117 | ||
| 118 | #else ns32000 | |
| 119 | /* Only the "interlock" field is used for hardware exclusion; | |
| 120 | * other fields are modified with normal instructions after | |
| 121 | * acquiring the interlock bit. | |
| 122 | */ | |
| 123 | simple_lock_data_t | |
| 124 | interlock; /* Interlock for remaining fields */ | |
| 125 | boolean_t want_write; /* Writer is waiting, or locked for write */ | |
| 126 | boolean_t want_upgrade; /* Read-to-write upgrade waiting */ | |
| 127 | boolean_t waiting; /* Someone is sleeping on lock */ | |
| 128 | boolean_t can_sleep; /* Can attempts to lock go to sleep */ | |
| 129 | int read_count; /* Number of accepted readers */ | |
| 130 | #endif /* ns32000 */ | |
| 131 | #endif /* vax */ | |
| 132 | char *thread; /* Thread that has lock, if recursive locking allowed */ | |
| 133 | /* (should be thread_t, but but we then have mutually | |
| 134 | recursive definitions) */ | |
| 135 | int recursion_depth;/* Depth of recursion */ | |
| 136 | }; | |
| 137 | ||
| 138 | typedef struct lock lock_data_t; | |
| 139 | typedef struct lock *lock_t; | |
| 140 | ||
| 141 | #if NCPUS > 1 | |
| 142 | void simple_lock_init(); | |
| 143 | void simple_lock(); | |
| 144 | void simple_unlock(); | |
| 145 | boolean_t simple_lock_try(); | |
| 146 | #else NCPUS > 1 | |
| 147 | /* | |
| 148 | * No multiprocessor locking is necessary. | |
| 149 | */ | |
| 150 | #define simple_lock_init(l) | |
| 151 | #define simple_lock(l) | |
| 152 | #define simple_unlock(l) | |
| 153 | #define simple_lock_try(l) (1) /* always succeeds */ | |
| 154 | #endif /* NCPUS > 1 */ | |
| 155 | ||
| 156 | /* Sleep locks must work even if no multiprocessing */ | |
| 157 | ||
| 158 | void lock_init(); | |
| 159 | void lock_sleepable(); | |
| 160 | void lock_write(); | |
| 161 | void lock_read(); | |
| 162 | void lock_done(); | |
| 163 | boolean_t lock_read_to_write(); | |
| 164 | void lock_write_to_read(); | |
| 165 | boolean_t lock_try_write(); | |
| 166 | boolean_t lock_try_read(); | |
| 167 | boolean_t lock_try_read_to_write(); | |
| 168 | ||
| 169 | #define lock_read_done(l) lock_done(l) | |
| 170 | #define lock_write_done(l) lock_done(l) | |
| 171 | ||
| 172 | void lock_set_recursive(); | |
| 173 | void lock_clear_recursive(); | |
| 174 | ||
| 175 | #endif /* !_LOCK_H_ */ |