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/* $OpenBSD: mutex.h,v 1.5 2013/07/10 21:31:12 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.
*/
#ifndef _MACHINE_MUTEX_H_
#define _MACHINE_MUTEX_H_
/*
* XXX - we don't really need the mtx_lock field, we can use mtx_oldipl
* as the lock to save some space.
*/
struct mutex {
__volatile int mtx_lock;
int mtx_wantipl;
int mtx_oldipl;
void *mtx_owner;
};
/*
* To prevent lock ordering problems with the kernel lock, we need to
* make sure we block all interrupts that can grab the kernel lock.
* The simplest way to achieve this is to make sure mutexes always
* raise the interrupt priority level to the highest level that has
* interrupts that grab the kernel lock.
*/
#ifdef MULTIPROCESSOR
#define __MUTEX_IPL(ipl) \
(((ipl) > IPL_NONE && (ipl) < IPL_VM) ? IPL_VM : (ipl))
#else
#define __MUTEX_IPL(ipl) (ipl)
#endif
#define MUTEX_INITIALIZER(ipl) { 0, __MUTEX_IPL((ipl)), 0, NULL }
void __mtx_init(struct mutex *, int);
#define mtx_init(mtx, ipl) __mtx_init((mtx), __MUTEX_IPL((ipl)))
#define MUTEX_ASSERT_LOCKED(mtx) do { \
if ((mtx)->mtx_lock != 1 || \
(mtx)->mtx_owner != curcpu()) \
panic("mutex %p not held in %s", (mtx), __func__); \
} while (0)
#define MUTEX_ASSERT_UNLOCKED(mtx) do { \
if ((mtx)->mtx_lock == 1 && \
(mtx)->mtx_owner == curcpu()) \
panic("mutex %p held in %s", (mtx), __func__); \
} while (0)
#define MUTEX_OLDIPL(mtx) (mtx)->mtx_oldipl
#endif
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