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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. /**
  30.  * @file    as_ht.c
  31.  * @brief   Address space functions for global page hash table.
  32.  */
  33.  
  34. #include <genarch/mm/as_ht.h>
  35. #include <genarch/mm/page_ht.h>
  36. #include <mm/as.h>
  37. #include <mm/frame.h>
  38. #include <arch/types.h>
  39. #include <typedefs.h>
  40. #include <memstr.h>
  41. #include <adt/hash_table.h>
  42. #include <synch/mutex.h>
  43.  
  44. static pte_t *ht_create(int flags);
  45. static void ht_destroy(pte_t *page_table);
  46.  
  47. static void ht_lock(as_t *as, bool lock);
  48. static void ht_unlock(as_t *as, bool unlock);
  49.  
  50. as_operations_t as_ht_operations = {
  51.     .page_table_create = ht_create,
  52.     .page_table_destroy = ht_destroy,
  53.     .page_table_lock = ht_lock,
  54.     .page_table_unlock = ht_unlock,
  55. };
  56.  
  57.  
  58. /** Page hash table create.
  59.  *
  60.  * The page hash table will be created only once
  61.  * and will be shared by all address spaces.
  62.  *
  63.  * @param flags Ignored.
  64.  *
  65.  * @return Returns NULL.
  66.  */
  67. pte_t *ht_create(int flags)
  68. {
  69.     if (flags & FLAG_AS_KERNEL) {
  70.         hash_table_create(&page_ht, PAGE_HT_ENTRIES, 2, &ht_operations);
  71.         mutex_initialize(&page_ht_lock);
  72.     }
  73.     return NULL;
  74. }
  75.  
  76. /** Destroy page table.
  77.  *
  78.  * Actually do nothing as the global page hash table is used.
  79.  *
  80.  * @param page_table This parameter is ignored.
  81.  */
  82. void ht_destroy(pte_t *page_table)
  83. {
  84.     /* No-op. */
  85. }
  86.  
  87. /** Lock page table.
  88.  *
  89.  * Lock address space and page hash table.
  90.  * Interrupts must be disabled.
  91.  *
  92.  * @param as Address space.
  93.  * @param lock If false, do not attempt to lock the address space.
  94.  */
  95. void ht_lock(as_t *as, bool lock)
  96. {
  97.     if (lock)
  98.         mutex_lock(&as->lock);
  99.     mutex_lock(&page_ht_lock);
  100. }
  101.  
  102. /** Unlock page table.
  103.  *
  104.  * Unlock address space and page hash table.
  105.  * Interrupts must be disabled.
  106.  *
  107.  * @param as Address space.
  108.  * @param unlock If false, do not attempt to lock the address space.
  109.  */
  110. void ht_unlock(as_t *as, bool unlock)
  111. {
  112.     mutex_unlock(&page_ht_lock);
  113.     if (unlock)
  114.         mutex_unlock(&as->lock);
  115. }
  116.