include/sys/lock.h

   1 /*      $NetBSD: lock.h,v 1.86 2010/07/01 13:00:57 hannken Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1999, 2000, 2006, 2007 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 of the Numerical Aerospace Simulation Facility,
   9  * NASA Ames Research Center, by Ross Harvey, and by Andrew Doran.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * Copyright (c) 1995
  35  *      The Regents of the University of California.  All rights reserved.
  36  *
  37  * This code contains ideas from software contributed to Berkeley by
  38  * Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
  39  * System project at Carnegie-Mellon University.
  40  *
  41  * Redistribution and use in source and binary forms, with or without
  42  * modification, are permitted provided that the following conditions
  43  * are met:
  44  * 1. Redistributions of source code must retain the above copyright
  45  *    notice, this list of conditions and the following disclaimer.
  46  * 2. Redistributions in binary form must reproduce the above copyright
  47  *    notice, this list of conditions and the following disclaimer in the
  48  *    documentation and/or other materials provided with the distribution.
  49  * 3. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  *
  65  *      @(#)lock.h      8.12 (Berkeley) 5/19/95
  66  */
  67
  68 #ifndef _SYS_LOCK_H_
  69 #define _SYS_LOCK_H_
  70
  71 #include <sys/stdint.h>
  72 #include <sys/mutex.h>
  73
  74 #include <machine/lock.h>
  75
  76 #ifdef _KERNEL
  77
  78 /*
  79  * From <machine/lock.h>.
  80  */
  81 #ifndef SPINLOCK_SPIN_HOOK
  82 #define SPINLOCK_SPIN_HOOK
  83 #endif
  84 #ifndef SPINLOCK_BACKOFF_HOOK
  85 #define SPINLOCK_BACKOFF_HOOK           nullop(NULL)
  86 #endif
  87 #ifndef SPINLOCK_BACKOFF_MIN
  88 #define SPINLOCK_BACKOFF_MIN    4
  89 #endif
  90 #ifndef SPINLOCK_BACKOFF_MAX
  91 #define SPINLOCK_BACKOFF_MAX    128
  92 #endif
  93
  94 #define SPINLOCK_BACKOFF(count)                                 \
  95 do {                                                            \
  96         int __i;                                                \
  97         for (__i = (count); __i != 0; __i--) {                  \
  98                 SPINLOCK_BACKOFF_HOOK;                          \
  99         }                                                       \
 100         if ((count) < SPINLOCK_BACKOFF_MAX)                     \
 101                 (count) += (count);                             \
 102 } while (/* CONSTCOND */ 0);
 103
 104 #define SPINLOCK_RUN_HOOK(count)        ((count) >= SPINLOCK_BACKOFF_MAX)
 105
 106 #ifdef LOCKDEBUG
 107 #define SPINLOCK_SPINOUT(spins)         ((spins)++ > 0x0fffffff)
 108 #else
 109 #define SPINLOCK_SPINOUT(spins)         ((void)(spins), 0)
 110 #endif
 111
 112 extern __cpu_simple_lock_t kernel_lock[];
 113
 114 #endif /* _KERNEL */
 115
 116 #endif /* _SYS_LOCK_H_ */