fbfeb4f2a9
sometimes do not serve as memory barriers, allowing memory references to bleed outside of critical sections. It's possible that this is the reason for pkgbuild's longstanding crashiness.
81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
/* $NetBSD: mutex.h,v 1.6 2009/04/24 17:49:51 ad Exp $ */
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/*-
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* Copyright (c) 2002, 2006, 2009 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe and Andrew Doran.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _X86_MUTEX_H_
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#define _X86_MUTEX_H_
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struct kmutex {
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union {
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volatile uintptr_t mtxa_owner;
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#ifdef __MUTEX_PRIVATE
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struct {
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volatile uint8_t mtxs_dummy;
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ipl_cookie_t mtxs_ipl;
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__cpu_simple_lock_t mtxs_lock;
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volatile uint8_t mtxs_unused;
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} s;
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#endif
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} u;
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};
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#ifdef __MUTEX_PRIVATE
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#define mtx_owner u.mtxa_owner
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#define mtx_ipl u.s.mtxs_ipl
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#define mtx_lock u.s.mtxs_lock
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#define __HAVE_MUTEX_STUBS 1
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#define __HAVE_SPIN_MUTEX_STUBS 1
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#define __HAVE_SIMPLE_MUTEXES 1
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/*
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* MUTEX_RECEIVE: technically, no memory barrier is required
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* as 'ret' implies a load fence. However we need this to
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* handle a bug with some Opteron revisions. See patch.c,
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* lock_stubs.S.
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*/
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#define MUTEX_RECEIVE(mtx) membar_consumer()
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/*
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* MUTEX_GIVE: no memory barrier required, as _lock_cas() will take care of it.
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*/
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#define MUTEX_GIVE(mtx) /* nothing */
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#define MUTEX_CAS(p, o, n) \
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(_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
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unsigned long _atomic_cas_ulong(volatile unsigned long *,
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unsigned long, unsigned long);
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#endif /* __MUTEX_PRIVATE */
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#endif /* _X86_MUTEX_H_ */
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