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Diffstat (limited to 'sys/vm/lock.h')
| -rw-r--r-- | sys/vm/lock.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/sys/vm/lock.h b/sys/vm/lock.h new file mode 100644 index 00000000000..1157b83f356 --- /dev/null +++ b/sys/vm/lock.h @@ -0,0 +1,174 @@ +/* $NetBSD: lock.h,v 1.8 1994/10/30 19:11:11 cgd Exp $ */ + +/* + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * The Mach Operating System project at Carnegie-Mellon University. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)lock.h 8.1 (Berkeley) 6/11/93 + * + * + * Copyright (c) 1987, 1990 Carnegie-Mellon University. + * All rights reserved. + * + * Authors: Avadis Tevanian, Jr., Michael Wayne Young + * + * Permission to use, copy, modify and distribute this software and + * its documentation is hereby granted, provided that both the copyright + * notice and this permission notice appear in all copies of the + * software, derivative works or modified versions, and any portions + * thereof, and that both notices appear in supporting documentation. + * + * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" + * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND + * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. + * + * Carnegie Mellon requests users of this software to return to + * + * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU + * School of Computer Science + * Carnegie Mellon University + * Pittsburgh PA 15213-3890 + * + * any improvements or extensions that they make and grant Carnegie the + * rights to redistribute these changes. + */ + +/* + * Locking primitives definitions + */ + +#ifndef _LOCK_H_ +#define _LOCK_H_ + +#define NCPUS 1 /* XXX */ + +/* + * A simple spin lock. + */ + +struct slock { + int lock_data; /* in general 1 bit is sufficient */ +}; + +typedef struct slock simple_lock_data_t; +typedef struct slock *simple_lock_t; + +/* + * The general lock structure. Provides for multiple readers, + * upgrading from read to write, and sleeping until the lock + * can be gained. + */ + +struct lock { +#ifdef vax + /* + * Efficient VAX implementation -- see field description below. + */ + unsigned int read_count:16, + want_upgrade:1, + want_write:1, + waiting:1, + can_sleep:1, + :0; + + simple_lock_data_t interlock; +#else /* vax */ +#ifdef ns32000 + /* + * Efficient ns32000 implementation -- + * see field description below. + */ + simple_lock_data_t interlock; + unsigned int read_count:16, + want_upgrade:1, + want_write:1, + waiting:1, + can_sleep:1, + :0; + +#else /* ns32000 */ + /* Only the "interlock" field is used for hardware exclusion; + * other fields are modified with normal instructions after + * acquiring the interlock bit. + */ + simple_lock_data_t + interlock; /* Interlock for remaining fields */ + boolean_t want_write; /* Writer is waiting, or locked for write */ + boolean_t want_upgrade; /* Read-to-write upgrade waiting */ + boolean_t waiting; /* Someone is sleeping on lock */ + boolean_t can_sleep; /* Can attempts to lock go to sleep */ + int read_count; /* Number of accepted readers */ +#endif /* ns32000 */ +#endif /* vax */ + void *thread; /* Thread that has lock, if recursive locking allowed */ + /* (should be thread_t, but but we then have mutually + recursive definitions) */ + int recursion_depth;/* Depth of recursion */ +}; + +typedef struct lock lock_data_t; +typedef struct lock *lock_t; + +#if NCPUS > 1 +__BEGIN_DECLS +void simple_lock __P((simple_lock_t)); +void simple_lock_init __P((simple_lock_t)); +boolean_t simple_lock_try __P((simple_lock_t)); +void simple_unlock __P((simple_lock_t)); +__END_DECLS +#else /* No multiprocessor locking is necessary. */ +#define simple_lock(l) +#define simple_lock_init(l) +#define simple_lock_try(l) (1) /* Always succeeds. */ +#define simple_unlock(l) +#endif + +/* Sleep locks must work even if no multiprocessing. */ + +#define lock_read_done(l) lock_done(l) +#define lock_write_done(l) lock_done(l) + +void lock_clear_recursive __P((lock_t)); +void lock_done __P((lock_t)); +void lock_init __P((lock_t, boolean_t)); +void lock_read __P((lock_t)); +boolean_t lock_read_to_write __P((lock_t)); +void lock_set_recursive __P((lock_t)); +void lock_sleepable __P((lock_t, boolean_t)); +boolean_t lock_try_read __P((lock_t)); +boolean_t lock_try_read_to_write __P((lock_t)); +boolean_t lock_try_write __P((lock_t)); +void lock_write __P((lock_t)); +void lock_write_to_read __P((lock_t)); +#endif /* !_LOCK_H_ */ |