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  1. /*
  2.  * Copyright (C) 2006 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 <genarch/mm/asid_fifo.h>
  30. #include <arch/mm/asid.h>
  31. #include <mm/asid.h>
  32. #include <typedefs.h>
  33. #include <adt/fifo.h>
  34.  
  35. /**
  36.  * FIFO queue containing unassigned ASIDs.
  37.  * Can be only accessed when asidlock is held.
  38.  */
  39. FIFO_INITIALIZE(free_asids, asid_t, ASIDS_ALLOCABLE);
  40.  
  41. /** Initialize data structures for O(1) ASID allocation and deallocation. */
  42. void asid_fifo_init(void)
  43. {
  44.     int i;
  45.    
  46.     for (i = 0; i < ASIDS_ALLOCABLE; i++) {
  47.         fifo_push(free_asids, ASID_START + i);
  48.     }
  49. }
  50.  
  51. /** Allocate free ASID.
  52.  *
  53.  * Allocation runs in O(1).
  54.  *
  55.  * @return Free ASID.
  56.  */
  57. asid_t asid_find_free(void)
  58. {
  59.     return fifo_pop(free_asids);
  60. }
  61.  
  62. /** Return ASID among free ASIDs.
  63.  *
  64.  * This operation runs in O(1).
  65.  *
  66.  * @param asid ASID being freed.
  67.  */
  68. void asid_put_arch(asid_t asid)
  69. {
  70.     fifo_push(free_asids, asid);
  71. }
  72.