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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/page_ht.h>
  30. #include <mm/page.h>
  31. #include <mm/frame.h>
  32. #include <mm/heap.h>
  33. #include <arch/mm/asid.h>
  34. #include <arch/types.h>
  35. #include <typedefs.h>
  36. #include <arch/asm.h>
  37. #include <debug.h>
  38.  
  39. static void ht_mapping_insert(__address page, asid_t asid, __address frame, int flags, __address root);
  40. static pte_t *ht_mapping_find(__address page, asid_t asid, __address root);
  41.  
  42. page_operations_t page_ht_operations = {
  43.     .mapping_insert = ht_mapping_insert,
  44.     .mapping_find = ht_mapping_find
  45. };
  46.  
  47. /** Map page to frame using page hash table.
  48.  *
  49.  * Map virtual address 'page' to physical address 'frame'
  50.  * using 'flags'.
  51.  *
  52.  * @param page Virtual address of the page to be mapped.
  53.  * @param asid Address space to which page belongs.
  54.  * @param frame Physical address of memory frame to which the mapping is done.
  55.  * @param flags Flags to be used for mapping.
  56.  * @param root Ignored.
  57.  */
  58. void ht_mapping_insert(__address page, asid_t asid, __address frame, int flags, __address root)
  59. {
  60.     pte_t *t, *u = NULL;
  61.    
  62.     t = HT_HASH(page, asid);
  63.     if (!HT_SLOT_EMPTY(t)) {
  64.         u = (pte_t *) malloc(sizeof(pte_t));    /* FIXME: use slab allocator for this */
  65.         if (!u)
  66.             panic("could not allocate memory for hash table\n");
  67.         *u = *t;
  68.     }
  69.     HT_SET_NEXT(t, u);
  70.     HT_SET_RECORD(t, page, asid, frame, flags);
  71. }
  72.  
  73. /** Find mapping for virtual page in page hash table.
  74.  *
  75.  * Find mapping for virtual page.
  76.  *
  77.  * @param page Virtual page.
  78.  * @param asid Address space to wich page belongs.
  79.  * @param root Ignored.
  80.  *
  81.  * @return NULL if there is no such mapping; requested mapping otherwise.
  82.  */
  83. pte_t *ht_mapping_find(__address page, asid_t asid, __address root)
  84. {
  85.     pte_t *t;
  86.    
  87.     t = HT_HASH(page, asid);
  88.     while (!HT_COMPARE(page, asid, t) && HT_GET_NEXT(t))
  89.         t = HT_GET_NEXT(t);
  90.    
  91.     return HT_COMPARE(page, asid, t) ? t : NULL;
  92. }
  93.