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/* $NetBSD: common_lock.h,v 1.2 2017/09/16 23:30:50 christos Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Machine-dependent spin lock operations using the builtin compiler atomic
* primitives.
*/
#ifndef _SYS_COMMON_LOCK_H_
#define _SYS_COMMON_LOCK_H_
static __inline int
__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
{
return *__ptr != __SIMPLELOCK_UNLOCKED;
}
static __inline int
__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
{
return *__ptr == __SIMPLELOCK_UNLOCKED;
}
static __inline void
__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
{
#if 1
*__ptr = __SIMPLELOCK_UNLOCKED;
#else
__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED);
#endif
}
static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
{
#if 1
*__ptr = __SIMPLELOCK_LOCKED;
#else
__atomic_store_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_RELAXED);
#endif
}
static __inline void __unused
__cpu_simple_lock_init(__cpu_simple_lock_t *__ptr)
{
#if 1
*__ptr = __SIMPLELOCK_UNLOCKED;
#else
__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELAXED);
#endif
}
static __inline void __unused
__cpu_simple_lock(__cpu_simple_lock_t *__ptr)
{
while (__atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_LOCKED) {
/* do nothing */
}
}
static __inline int __unused
__cpu_simple_lock_try(__cpu_simple_lock_t *__ptr)
{
return __atomic_exchange_n(__ptr, __SIMPLELOCK_LOCKED, __ATOMIC_ACQUIRE) == __SIMPLELOCK_UNLOCKED;
}
static __inline void __unused
__cpu_simple_unlock(__cpu_simple_lock_t *__ptr)
{
__atomic_store_n(__ptr, __SIMPLELOCK_UNLOCKED, __ATOMIC_RELEASE);
}
#endif /* _SYS_COMMON_LOCK_H_ */
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