sys/arch/ia64/include/lock.h

   1 /*      $NetBSD: lock.h,v 1.3 2008/04/28 20:23:25 martin Exp $  */
   2
   3 /*-
   4  * Copyright (c) 2000 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.
   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 /*
  33  * Machine-dependent spin lock operations.
  34  */
  35
  36 #ifndef _IA64_LOCK_H_
  37 #define _IA64_LOCK_H_
  38
  39 static __inline int
  40 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
  41 {
  42         return *__ptr == __SIMPLELOCK_LOCKED;
  43 }
  44
  45 static __inline int
  46 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
  47 {
  48         return *__ptr == __SIMPLELOCK_UNLOCKED;
  49 }
  50
  51 static __inline void
  52 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
  53 {
  54
  55         *__ptr = __SIMPLELOCK_LOCKED;
  56 }
  57
  58 static __inline void
  59 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
  60 {
  61
  62         *__ptr = __SIMPLELOCK_UNLOCKED;
  63 }
  64
  65 #ifdef _KERNEL
  66
  67 #define SPINLOCK_SPIN_HOOK      /* nothing */
  68 #define SPINLOCK_BACKOFF_HOOK   /* XXX(kochi): hint@pause */
  69
  70 #endif
  71
  72 static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
  73         __unused;
  74 static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
  75         __unused;
  76 static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
  77         __unused;
  78 static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
  79         __unused;
  80
  81 static __inline void
  82 __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
  83 {
  84
  85         *lockp = __SIMPLELOCK_UNLOCKED;
  86         __insn_barrier();
  87 }
  88
  89 static __inline int
  90 __cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
  91 {
  92         uint8_t val;
  93
  94         val = __SIMPLELOCK_LOCKED;
  95         __asm volatile ("xchg1 %0=[%1],%2" :
  96             "=r" (val)
  97             :"r" (lockp), "r" (val)
  98             :"memory");
  99         return val == __SIMPLELOCK_UNLOCKED;
 100 }
 101
 102 static __inline void
 103 __cpu_simple_lock(__cpu_simple_lock_t *lockp)
 104 {
 105
 106         while (!__cpu_simple_lock_try(lockp))
 107                 /* nothing */;
 108         __insn_barrier();
 109 }
 110
 111 static __inline void
 112 __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
 113 {
 114
 115         __insn_barrier();
 116         *lockp = __SIMPLELOCK_UNLOCKED;
 117 }
 118
 119 #endif /* _IA64_LOCK_H_ */