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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 <arch/barrier.h>
  33. #include <synch/spinlock.h>
  34. #include <print.h>
  35.  
  36. #ifdef __SMP__
  37.  
  38. void spinlock_initialize(spinlock_t *sl)
  39. {
  40.     sl->val = 0;
  41. }
  42.  
  43. #ifdef DEBUG_SPINLOCK
  44. void spinlock_lock(spinlock_t *sl)
  45. {
  46.     int i = 0;
  47.     __address caller = ((__u32 *) &sl)[-1];
  48.  
  49.     while (test_and_set(&sl->val)) {
  50.         if (i++ > 300000) {
  51.             printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller);
  52.             i = 0;
  53.         }
  54.     }
  55.     CS_ENTER_BARRIER();
  56.  
  57. }
  58. #else
  59. void spinlock_lock(spinlock_t *sl)
  60. {
  61.     /*
  62.      * Each architecture has its own efficient/recommended
  63.      * implementation of spinlock.
  64.      */
  65.     spinlock_arch(&sl->val);
  66.     CS_ENTER_BARRIER();
  67. }
  68. #endif
  69.  
  70. int spinlock_trylock(spinlock_t *sl)
  71. {
  72.     int rc;
  73.    
  74.     rc = !test_and_set(&sl->val);
  75.     CS_ENTER_BARRIER();
  76.    
  77.     return rc;
  78. }
  79.  
  80. void spinlock_unlock(spinlock_t *sl)
  81. {
  82.     CS_LEAVE_BARRIER();
  83.     sl->val = 0;
  84. }
  85.  
  86. #endif
  87.