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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 <synch/spinlock.h>
  38. #include <arch.h>
  39. #include <debug.h>
  40.  
  41. /**
  42.  * This lock protects the page hash table. Note that software must
  43.  * be still careful about ordering of writes to ensure consistent
  44.  * view of the page hash table for hardware helpers such as VHPT
  45.  * walker on ia64.
  46.  */
  47. SPINLOCK_INITIALIZE(page_ht_lock);
  48.  
  49. /**
  50.  * Page hash table pointer.
  51.  * The page hash table may be accessed only when page_ht_lock is held.
  52.  */
  53. pte_t *page_ht = NULL;
  54.  
  55. static void ht_mapping_insert(__address page, asid_t asid, __address frame, int flags, __address root);
  56. static pte_t *ht_mapping_find(__address page, asid_t asid, __address root);
  57.  
  58. page_operations_t page_ht_operations = {
  59.     .mapping_insert = ht_mapping_insert,
  60.     .mapping_find = ht_mapping_find
  61. };
  62.  
  63. /** Map page to frame using page hash table.
  64.  *
  65.  * Map virtual address 'page' to physical address 'frame'
  66.  * using 'flags'. In order not to disturb hardware searching,
  67.  * new mappings are appended to the end of the collision
  68.  * chain.
  69.  *
  70.  * @param page Virtual address of the page to be mapped.
  71.  * @param asid Address space to which page belongs.
  72.  * @param frame Physical address of memory frame to which the mapping is done.
  73.  * @param flags Flags to be used for mapping.
  74.  * @param root Ignored.
  75.  */
  76. void ht_mapping_insert(__address page, asid_t asid, __address frame, int flags, __address root)
  77. {
  78.     pte_t *t, *u;
  79.     ipl_t ipl;
  80.    
  81.     ipl = interrupts_disable();
  82.     spinlock_lock(&page_ht_lock);
  83.    
  84.     t = HT_HASH(page, asid);
  85.     if (!HT_SLOT_EMPTY(t)) {
  86.    
  87.         /*
  88.          * The slot is occupied.
  89.          * Walk through the collision chain and append the mapping to its end.
  90.          */
  91.          
  92.         do {
  93.             u = t;
  94.             if (HT_COMPARE(page, asid, t)) {
  95.                 /*
  96.                  * Nothing to do,
  97.                  * the record is already there.
  98.                  */
  99.                 spinlock_unlock(&page_ht_lock);
  100.                 interrupts_restore(ipl);
  101.                 return;
  102.             }
  103.         } while ((t = HT_GET_NEXT(t)));
  104.    
  105.         t = (pte_t *) malloc(sizeof(pte_t));    /* FIXME: use slab allocator for this */
  106.         if (!t)
  107.             panic("could not allocate memory\n");
  108.  
  109.         HT_SET_NEXT(u, t);
  110.     }
  111.    
  112.     HT_SET_RECORD(t, page, asid, frame, flags);
  113.     HT_SET_NEXT(t, NULL);
  114.    
  115.     spinlock_unlock(&page_ht_lock);
  116.     interrupts_restore(ipl);
  117. }
  118.  
  119. /** Find mapping for virtual page in page hash table.
  120.  *
  121.  * Find mapping for virtual page.
  122.  *
  123.  * Interrupts must be disabled.
  124.  *
  125.  * @param page Virtual page.
  126.  * @param asid Address space to wich page belongs.
  127.  * @param root Ignored.
  128.  *
  129.  * @return NULL if there is no such mapping; requested mapping otherwise.
  130.  */
  131. pte_t *ht_mapping_find(__address page, asid_t asid, __address root)
  132. {
  133.     pte_t *t;
  134.    
  135.     spinlock_lock(&page_ht_lock);
  136.     t = HT_HASH(page, asid);
  137.     if (!HT_SLOT_EMPTY(t)) {
  138.         while (!HT_COMPARE(page, asid, t) && HT_GET_NEXT(t))
  139.             t = HT_GET_NEXT(t);
  140.         t = HT_COMPARE(page, asid, t) ? t : NULL;
  141.     } else {
  142.         t = NULL;
  143.     }
  144.     spinlock_unlock(&page_ht_lock);
  145.     return t;
  146. }
  147.  
  148. /** Invalidate page hash table.
  149.  *
  150.  * Interrupts must be disabled.
  151.  */
  152. void ht_invalidate_all(void)
  153. {
  154.     pte_t *t, *u;
  155.     int i;
  156.    
  157.     spinlock_lock(&page_ht_lock);
  158.     for (i = 0; i < HT_ENTRIES; i++) {
  159.         if (!HT_SLOT_EMPTY(&page_ht[i])) {
  160.             t = HT_GET_NEXT(&page_ht[i]);
  161.             while (t) {
  162.                 u = t;
  163.                 t = HT_GET_NEXT(t);
  164.                 free(u);        /* FIXME: use slab allocator for this */
  165.             }
  166.             HT_INVALIDATE_SLOT(&page_ht[i]);
  167.         }
  168.     }
  169.     spinlock_unlock(&page_ht_lock);
  170. }
  171.