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/* $OpenBSD: mutex.h,v 1.6 2009/04/27 21:48:56 kettenis Exp $ */
/*
* Copyright (c) 2004 Artur Grabowski <art@openbsd.org>
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
*/
/*
* Portions copyright (c) 2010, Intel Corporation
*/
#ifndef __MUTEX_H__
#define __MUTEX_H__
/*
* A mutex is:
* - owned by a cpu.
* - non-recursive.
* - spinning.
* - not providing mutual exclusion between processes, only cpus.
* - providing interrupt blocking when necessary.
*
* Different mutexes can be nested, but not interleaved. This is ok:
* "mtx_enter(foo); mtx_enter(bar); mtx_leave(bar); mtx_leave(foo);"
* This is _not_ ok:
* "mtx_enter(foo); mtx_enter(bar); mtx_leave(foo); mtx_leave(bar);"
*/
struct mutex {
__volatile__ uint64_t mtx_lock;
};
/*
* Some architectures need to do magic for the ipl, so they need a macro.
*/
void mtx_init(struct mutex *);
void mtx_enter(struct mutex *);
void mtx_leave(struct mutex *);
#endif /* __MUTEX_H__ */
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