sparc/include/lock.h

1.2  pk /*	$NetBSD: lock.h,v 1.2 1998/10/05 19:58:19 pk Exp $ */
1.1  pk
1.1  pk /*-
1.1  pk  * Copyright (c) 1998 The NetBSD Foundation, Inc.
1.1  pk  * All rights reserved.
1.1  pk  *
1.1  pk  * This code is derived from software contributed to The NetBSD Foundation
1.1  pk  * by Paul Kranenburg.
1.1  pk  *
1.1  pk  * Redistribution and use in source and binary forms, with or without
1.1  pk  * modification, are permitted provided that the following conditions
1.1  pk  * are met:
1.1  pk  * 1. Redistributions of source code must retain the above copyright
1.1  pk  *    notice, this list of conditions and the following disclaimer.
1.1  pk  * 2. Redistributions in binary form must reproduce the above copyright
1.1  pk  *    notice, this list of conditions and the following disclaimer in the
1.1  pk  *    documentation and/or other materials provided with the distribution.
1.1  pk  * 3. All advertising materials mentioning features or use of this software
1.1  pk  *    must display the following acknowledgement:
1.1  pk  *        This product includes software developed by the NetBSD
1.1  pk  *        Foundation, Inc. and its contributors.
1.1  pk  * 4. Neither the name of The NetBSD Foundation nor the names of its
1.1  pk  *    contributors may be used to endorse or promote products derived
1.1  pk  *    from this software without specific prior written permission.
1.1  pk  *
1.1  pk  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
1.1  pk  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
1.1  pk  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
1.1  pk  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
1.1  pk  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.1  pk  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.1  pk  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.1  pk  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.1  pk  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.1  pk  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.1  pk  * POSSIBILITY OF SUCH DAMAGE.
1.1  pk  */
1.1  pk
1.1  pk #ifndef _MACHINE_LOCK_H
1.1  pk #define _MACHINE_LOCK_H
1.1  pk
1.1  pk /*
1.1  pk  * Machine dependent spin lock operations.
1.1  pk  */
1.1  pk
1.1  pk #if defined(_KERNEL)
1.1  pk
1.1  pk #include <sparc/sparc/asm.h>
1.1  pk
1.1  pk static void	simple_lock_init __P((__volatile struct simplelock *));
1.1  pk static void	simple_lock __P((__volatile struct simplelock *));
1.1  pk static int	simple_lock_try __P((__volatile struct simplelock *));
1.1  pk static void	simple_unlock __P((__volatile struct simplelock *));
1.1  pk
1.1  pk static __inline__ void
1.1  pk simple_lock_init (alp)
1.1  pk 	__volatile struct simplelock *alp;
1.1  pk {
1.2  pk
1.1  pk 	alp->lock_data = 0;
1.1  pk }
1.1  pk
1.1  pk static __inline__ void
1.1  pk simple_lock (alp)
1.1  pk 	__volatile struct simplelock *alp;
1.1  pk {
1.2  pk
1.2  pk 	/*
1.2  pk 	 * If someone else holds the lock use simple
1.2  pk 	 * reads until it is released, then retry the
1.2  pk 	 * atomic operation. This reduces memory bus contention
1.2  pk 	 * becaused the cache-coherency logic does not have to
1.2  pk 	 * broadcast invalidates on the lock while we spin on it.
1.2  pk 	 */
1.2  pk 	while (ldstub(&alp->lock_data) != 0) {
1.2  pk 		while (alp->lock_data != 0)
1.2  pk 			/*void*/;
1.2  pk 	}
1.1  pk }
1.1  pk
1.1  pk static __inline__ int
1.1  pk simple_lock_try (alp)
1.1  pk 	__volatile struct simplelock *alp;
1.1  pk {
1.2  pk
1.1  pk 	return (ldstub(&alp->lock_data) == 0);
1.1  pk }
1.1  pk
1.1  pk static __inline__ void
1.1  pk simple_unlock (alp)
1.1  pk 	__volatile struct simplelock *alp;
1.1  pk {
1.2  pk
1.1  pk 	alp->lock_data = 0;
1.1  pk }
1.1  pk #endif /* _KERNEL */
1.1  pk
1.1  pk #endif /* _MACHINE_LOCK_H */