Home | History | Annotate | Line # | Download | only in include
lock.h revision 1.5 
      1  1.5  thorpej /*	$NetBSD: lock.h,v 1.5 1999/07/27 22:22:33 thorpej Exp $ */
      2  1.1       pk 
      3  1.1       pk /*-
      4  1.4  thorpej  * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
      5  1.1       pk  * All rights reserved.
      6  1.1       pk  *
      7  1.1       pk  * This code is derived from software contributed to The NetBSD Foundation
      8  1.1       pk  * by Paul Kranenburg.
      9  1.1       pk  *
     10  1.1       pk  * Redistribution and use in source and binary forms, with or without
     11  1.1       pk  * modification, are permitted provided that the following conditions
     12  1.1       pk  * are met:
     13  1.1       pk  * 1. Redistributions of source code must retain the above copyright
     14  1.1       pk  *    notice, this list of conditions and the following disclaimer.
     15  1.1       pk  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.1       pk  *    notice, this list of conditions and the following disclaimer in the
     17  1.1       pk  *    documentation and/or other materials provided with the distribution.
     18  1.1       pk  * 3. All advertising materials mentioning features or use of this software
     19  1.1       pk  *    must display the following acknowledgement:
     20  1.1       pk  *        This product includes software developed by the NetBSD
     21  1.1       pk  *        Foundation, Inc. and its contributors.
     22  1.1       pk  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  1.1       pk  *    contributors may be used to endorse or promote products derived
     24  1.1       pk  *    from this software without specific prior written permission.
     25  1.1       pk  *
     26  1.1       pk  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  1.1       pk  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  1.1       pk  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  1.1       pk  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  1.1       pk  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  1.1       pk  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  1.1       pk  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  1.1       pk  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  1.1       pk  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  1.1       pk  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  1.1       pk  * POSSIBILITY OF SUCH DAMAGE.
     37  1.1       pk  */
     38  1.1       pk 
     39  1.1       pk #ifndef _MACHINE_LOCK_H
     40  1.1       pk #define _MACHINE_LOCK_H
     41  1.1       pk 
     42  1.1       pk /*
     43  1.1       pk  * Machine dependent spin lock operations.
     44  1.1       pk  */
     45  1.1       pk 
     46  1.1       pk #if defined(_KERNEL)
     47  1.1       pk 
     48  1.1       pk #include <sparc/sparc/asm.h>
     49  1.1       pk 
     50  1.5  thorpej /*
     51  1.5  thorpej  * The value for SIMPLELOCK_LOCKED is what ldstub() naturally stores
     52  1.5  thorpej  * `lock_data' given its address (and the fact that SPARC is big-endian).
     53  1.5  thorpej  */
     54  1.5  thorpej #define	SIMPLELOCK_LOCKED	0xff000000
     55  1.5  thorpej #define	SIMPLELOCK_UNLOCKED	0
     56  1.5  thorpej 
     57  1.4  thorpej static void	cpu_simple_lock_init __P((__volatile struct simplelock *));
     58  1.4  thorpej static void	cpu_simple_lock __P((__volatile struct simplelock *));
     59  1.4  thorpej static int	cpu_simple_lock_try __P((__volatile struct simplelock *));
     60  1.4  thorpej static void	cpu_simple_unlock __P((__volatile struct simplelock *));
     61  1.1       pk 
     62  1.1       pk static __inline__ void
     63  1.4  thorpej cpu_simple_lock_init (alp)
     64  1.1       pk 	__volatile struct simplelock *alp;
     65  1.1       pk {
     66  1.2       pk 
     67  1.5  thorpej 	alp->lock_data = SIMPLELOCK_UNLOCKED;
     68  1.1       pk }
     69  1.1       pk 
     70  1.1       pk static __inline__ void
     71  1.4  thorpej cpu_simple_lock (alp)
     72  1.1       pk 	__volatile struct simplelock *alp;
     73  1.1       pk {
     74  1.2       pk 
     75  1.2       pk 	/*
     76  1.2       pk 	 * If someone else holds the lock use simple
     77  1.2       pk 	 * reads until it is released, then retry the
     78  1.2       pk 	 * atomic operation. This reduces memory bus contention
     79  1.2       pk 	 * becaused the cache-coherency logic does not have to
     80  1.2       pk 	 * broadcast invalidates on the lock while we spin on it.
     81  1.2       pk 	 */
     82  1.5  thorpej 	while (ldstub(&alp->lock_data) != SIMPLELOCK_UNLOCKED) {
     83  1.5  thorpej 		while (alp->lock_data != SIMPLELOCK_UNLOCKED)
     84  1.2       pk 			/*void*/;
     85  1.2       pk 	}
     86  1.1       pk }
     87  1.1       pk 
     88  1.1       pk static __inline__ int
     89  1.4  thorpej cpu_simple_lock_try (alp)
     90  1.1       pk 	__volatile struct simplelock *alp;
     91  1.1       pk {
     92  1.2       pk 
     93  1.5  thorpej 	return (ldstub(&alp->lock_data) == SIMPLELOCK_UNLOCKED);
     94  1.1       pk }
     95  1.1       pk 
     96  1.1       pk static __inline__ void
     97  1.4  thorpej cpu_simple_unlock (alp)
     98  1.1       pk 	__volatile struct simplelock *alp;
     99  1.1       pk {
    100  1.2       pk 
    101  1.5  thorpej 	alp->lock_data = SIMPLELOCK_UNLOCKED;
    102  1.1       pk }
    103  1.3      chs 
    104  1.1       pk #endif /* _KERNEL */
    105  1.1       pk 
    106  1.1       pk #endif /* _MACHINE_LOCK_H */
    107