sys/arch/x86/include/mutex.h

   1 /*      $NetBSD: mutex.h,v 1.6 2009/04/24 17:49:51 ad Exp $     */
   2
   3 /*-
   4  * Copyright (c) 2002, 2006, 2009 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Jason R. Thorpe and Andrew Doran.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #ifndef _X86_MUTEX_H_
  33 #define _X86_MUTEX_H_
  34
  35 struct kmutex {
  36         union {
  37                 volatile uintptr_t      mtxa_owner;
  38 #ifdef __MUTEX_PRIVATE
  39                 struct {
  40                         volatile uint8_t        mtxs_dummy;
  41                         ipl_cookie_t            mtxs_ipl;
  42                         __cpu_simple_lock_t     mtxs_lock;
  43                         volatile uint8_t        mtxs_unused;
  44                 } s;
  45 #endif
  46         } u;
  47 };
  48
  49 #ifdef __MUTEX_PRIVATE
  50
  51 #define mtx_owner                       u.mtxa_owner
  52 #define mtx_ipl                         u.s.mtxs_ipl
  53 #define mtx_lock                        u.s.mtxs_lock
  54
  55 #define __HAVE_MUTEX_STUBS              1
  56 #define __HAVE_SPIN_MUTEX_STUBS         1
  57 #define __HAVE_SIMPLE_MUTEXES           1
  58
  59 /*
  60  * MUTEX_RECEIVE: technically, no memory barrier is required
  61  * as 'ret' implies a load fence.  However we need this to
  62  * handle a bug with some Opteron revisions.  See patch.c,
  63  * lock_stubs.S.
  64  */
  65 #define MUTEX_RECEIVE(mtx)              membar_consumer()
  66
  67 /*
  68  * MUTEX_GIVE: no memory barrier required, as _lock_cas() will take care of it.
  69  */
  70 #define MUTEX_GIVE(mtx)                 /* nothing */
  71
  72 #define MUTEX_CAS(p, o, n)              \
  73     (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
  74
  75 unsigned long   _atomic_cas_ulong(volatile unsigned long *,
  76     unsigned long, unsigned long);
  77
  78 #endif  /* __MUTEX_PRIVATE */
  79
  80 #endif /* _X86_MUTEX_H_ */