11.2Schristos/* $NetBSD: common_lock.h,v 1.2 2017/09/16 23:30:50 christos Exp $ */
21.1Smatt
31.1Smatt/*-
41.1Smatt * Copyright (c) 2014 The NetBSD Foundation, Inc.
51.1Smatt * All rights reserved.
61.1Smatt *
71.1Smatt * This code is derived from software contributed to The NetBSD Foundation
81.1Smatt * by Matt Thomas of 3am Software Foundry.
91.1Smatt *
101.1Smatt * Redistribution and use in source and binary forms, with or without
111.1Smatt * modification, are permitted provided that the following conditions
121.1Smatt * are met:
131.1Smatt * 1. Redistributions of source code must retain the above copyright
141.1Smatt *    notice, this list of conditions and the following disclaimer.
151.1Smatt * 2. Redistributions in binary form must reproduce the above copyright
161.1Smatt *    notice, this list of conditions and the following disclaimer in the
171.1Smatt *    documentation and/or other materials provided with the distribution.
181.1Smatt *
191.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.1Smatt * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.1Smatt * POSSIBILITY OF SUCH DAMAGE.
301.1Smatt */
311.1Smatt
321.1Smatt/*
331.1Smatt * Machine-dependent spin lock operations using the builtin compiler atomic
341.1Smatt * primitives.
351.1Smatt */
361.1Smatt
371.1Smatt#ifndef _SYS_COMMON_LOCK_H_
381.1Smatt#define	_SYS_COMMON_LOCK_H_
391.1Smatt
401.1Smattstatic __inline int
411.2Schristos__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
421.1Smatt{
431.1Smatt	return *__ptr != __SIMPLELOCK_UNLOCKED;
441.1Smatt}
451.1Smatt
461.1Smattstatic __inline int
471.2Schristos__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
481.1Smatt{
491.1Smatt	return *__ptr == __SIMPLELOCK_UNLOCKED;
501.1Smatt}
511.1Smatt
521.1Smattstatic __inline void
531.1Smatt__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
541.1Smatt{
551.1Smatt#if 1
561.1Smatt	*__ptr = __SIMPLELOCK_UNLOCKED;
571.1Smatt#else
581.1Smatt	__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED);
591.1Smatt#endif
601.1Smatt}
611.1Smatt
621.1Smattstatic __inline void
631.1Smatt__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
641.1Smatt{
651.1Smatt#if 1
661.1Smatt	*__ptr = __SIMPLELOCK_LOCKED;
671.1Smatt#else
681.1Smatt	__atomic_store_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_RELAXED);
691.1Smatt#endif
701.1Smatt}
711.1Smatt
721.1Smattstatic __inline void __unused
731.1Smatt__cpu_simple_lock_init(__cpu_simple_lock_t *__ptr)
741.1Smatt{
751.1Smatt#if 1
761.1Smatt	*__ptr = __SIMPLELOCK_UNLOCKED;
771.1Smatt#else
781.1Smatt	__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED);
791.1Smatt#endif
801.1Smatt}
811.1Smatt
821.1Smattstatic __inline void __unused
831.1Smatt__cpu_simple_lock(__cpu_simple_lock_t *__ptr)
841.1Smatt{
851.1Smatt	while (__atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_LOCKED) {
861.1Smatt		/* do nothing */
871.1Smatt	}
881.1Smatt}
891.1Smatt
901.1Smattstatic __inline int __unused
911.1Smatt__cpu_simple_lock_try(__cpu_simple_lock_t *__ptr)
921.1Smatt{
931.1Smatt	return __atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_UNLOCKED;
941.1Smatt}
951.1Smatt
961.1Smattstatic __inline void __unused
971.1Smatt__cpu_simple_unlock(__cpu_simple_lock_t *__ptr)
981.1Smatt{
991.1Smatt	__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELEASE);
1001.1Smatt}
1011.1Smatt
1021.1Smatt#endif /* _SYS_COMMON_LOCK_H_ */
103