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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <arch.h>
  30.  
  31. #include <arch/atomic.h>
  32. #include <synch/spinlock.h>
  33.  
  34. #ifdef __SMP__
  35.  
  36. void spinlock_initialize(spinlock_t *sl)
  37. {
  38.     sl->val = 0;
  39. }
  40.  
  41. #ifdef DEBUG_SPINLOCK
  42. void spinlock_lock(spinlock_t *sl)
  43. {
  44.     int i = 0;
  45.     __address caller = ((__u32 *) &sl)[-1];
  46.  
  47.     while (test_and_set(&sl->val)) {
  48.         if (i++ > 300000) {
  49.             printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller);
  50.             i = 0;
  51.         }
  52.     }
  53.  
  54. }
  55. #else
  56. void spinlock_lock(spinlock_t *sl)
  57. {
  58.     /*
  59.      * Each architecture has its own efficient/recommended
  60.      * implementation of spinlock.
  61.      */
  62.     spinlock_arch(&sl->val);
  63. }
  64. #endif
  65.  
  66. int spinlock_trylock(spinlock_t *sl)
  67. {
  68.     return !test_and_set(&sl->val);
  69. }
  70.  
  71. void spinlock_unlock(spinlock_t *sl)
  72. {
  73.     sl->val = 0;
  74. }
  75.  
  76. #endif
  77.