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/* $OpenBSD: kern_lock.c,v 1.49 2017/04/20 15:06:47 visa Exp $ */
/*
* Copyright (c) 1995
* The Regents of the University of California. All rights reserved.
*
* This code contains ideas from software contributed to Berkeley by
* Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
* System project at Carnegie-Mellon University.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)kern_lock.c 8.18 (Berkeley) 5/21/95
*/
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/systm.h>
#include <sys/sched.h>
#include <sys/witness.h>
#ifdef MP_LOCKDEBUG
/* CPU-dependent timing, this needs to be settable from ddb. */
int __mp_lock_spinout = 200000000;
#endif
#if defined(MULTIPROCESSOR)
/*
* Functions for manipulating the kernel_lock. We put them here
* so that they show up in profiles.
*/
struct __mp_lock kernel_lock;
void
_kernel_lock_init(void)
{
__mp_lock_init(&kernel_lock);
}
/*
* Acquire/release the kernel lock. Intended for use in the scheduler
* and the lower half of the kernel.
*/
void
_kernel_lock(const char *file, int line)
{
SCHED_ASSERT_UNLOCKED();
#ifdef WITNESS
___mp_lock(&kernel_lock, file, line);
#else
__mp_lock(&kernel_lock);
#endif
}
void
_kernel_unlock(void)
{
__mp_unlock(&kernel_lock);
}
int
_kernel_lock_held(void)
{
return (__mp_lock_held(&kernel_lock));
}
#ifdef WITNESS
void
_mp_lock_init(struct __mp_lock *mpl, struct lock_type *type)
{
mpl->mpl_lock_obj.lo_name = type->lt_name;
mpl->mpl_lock_obj.lo_type = type;
if (mpl == &kernel_lock)
mpl->mpl_lock_obj.lo_flags = LO_WITNESS | LO_INITIALIZED |
LO_SLEEPABLE | (LO_CLASS_KERNEL_LOCK << LO_CLASSSHIFT);
else if (mpl == &sched_lock)
mpl->mpl_lock_obj.lo_flags = LO_WITNESS | LO_INITIALIZED |
LO_RECURSABLE | (LO_CLASS_SCHED_LOCK << LO_CLASSSHIFT);
WITNESS_INIT(&mpl->mpl_lock_obj, type);
___mp_lock_init(mpl);
}
#endif /* WITNESS */
#endif /* MULTIPROCESSOR */
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