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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. /** @addtogroup genarchmm
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Virtual Address Translation (VAT) for global page hash table.
  36.  */
  37.  
  38. #include <genarch/mm/page_ht.h>
  39. #include <mm/page.h>
  40. #include <arch/mm/page.h>
  41. #include <mm/frame.h>
  42. #include <mm/slab.h>
  43. #include <mm/as.h>
  44. #include <arch/mm/asid.h>
  45. #include <arch/types.h>
  46. #include <arch/asm.h>
  47. #include <synch/spinlock.h>
  48. #include <arch.h>
  49. #include <debug.h>
  50. #include <memstr.h>
  51. #include <adt/hash_table.h>
  52. #include <align.h>
  53.  
  54. static index_t hash(unative_t key[]);
  55. static bool compare(unative_t key[], count_t keys, link_t *item);
  56. static void remove_callback(link_t *item);
  57.  
  58. static void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags);
  59. static void ht_mapping_remove(as_t *as, uintptr_t page);
  60. static pte_t *ht_mapping_find(as_t *as, uintptr_t page);
  61.  
  62. /**
  63.  * This lock protects the page hash table. It must be acquired
  64.  * after address space lock and after any address space area
  65.  * locks.
  66.  */
  67. mutex_t page_ht_lock;
  68.  
  69. /**
  70.  * Page hash table.
  71.  * The page hash table may be accessed only when page_ht_lock is held.
  72.  */
  73. hash_table_t page_ht;
  74.  
  75. /** Hash table operations for page hash table. */
  76. hash_table_operations_t ht_operations = {
  77.     .hash = hash,
  78.     .compare = compare,
  79.     .remove_callback = remove_callback
  80. };
  81.  
  82. /** Page mapping operations for page hash table architectures. */
  83. page_mapping_operations_t ht_mapping_operations = {
  84.     .mapping_insert = ht_mapping_insert,
  85.     .mapping_remove = ht_mapping_remove,
  86.     .mapping_find = ht_mapping_find
  87. };
  88.  
  89. /** Compute page hash table index.
  90.  *
  91.  * @param key Array of two keys (i.e. page and address space).
  92.  *
  93.  * @return Index into page hash table.
  94.  */
  95. index_t hash(unative_t key[])
  96. {
  97.     as_t *as = (as_t *) key[KEY_AS];
  98.     uintptr_t page = (uintptr_t) key[KEY_PAGE];
  99.     index_t index;
  100.    
  101.     /*
  102.      * Virtual page addresses have roughly the same probability
  103.      * of occurring. Least significant bits of VPN compose the
  104.      * hash index.
  105.      */
  106.     index = ((page >> PAGE_WIDTH) & (PAGE_HT_ENTRIES-1));
  107.    
  108.     /*
  109.      * Address space structures are likely to be allocated from
  110.      * similar addresses. Least significant bits compose the
  111.      * hash index.
  112.      */
  113.     index |= ((unative_t) as) & (PAGE_HT_ENTRIES-1);
  114.    
  115.     return index;
  116. }
  117.  
  118. /** Compare page hash table item with page and/or address space.
  119.  *
  120.  * @param key Array of one or two keys (i.e. page and/or address space).
  121.  * @param keys Number of keys passed.
  122.  * @param item Item to compare the keys with.
  123.  *
  124.  * @return true on match, false otherwise.
  125.  */
  126. bool compare(unative_t key[], count_t keys, link_t *item)
  127. {
  128.     pte_t *t;
  129.  
  130.     ASSERT(item);
  131.     ASSERT((keys > 0) && (keys <= PAGE_HT_KEYS));
  132.  
  133.     /*
  134.      * Convert item to PTE.
  135.      */
  136.     t = hash_table_get_instance(item, pte_t, link);
  137.  
  138.     if (keys == PAGE_HT_KEYS) {
  139.         return (key[KEY_AS] == (uintptr_t) t->as) && (key[KEY_PAGE] == t->page);
  140.     } else {
  141.         return (key[KEY_AS] == (uintptr_t) t->as);
  142.     }
  143. }
  144.  
  145. /** Callback on page hash table item removal.
  146.  *
  147.  * @param item Page hash table item being removed.
  148.  */
  149. void remove_callback(link_t *item)
  150. {
  151.     pte_t *t;
  152.  
  153.     ASSERT(item);
  154.  
  155.     /*
  156.      * Convert item to PTE.
  157.      */
  158.     t = hash_table_get_instance(item, pte_t, link);
  159.  
  160.     free(t);
  161. }
  162.  
  163. /** Map page to frame using page hash table.
  164.  *
  165.  * Map virtual address page to physical address frame
  166.  * using flags.
  167.  *
  168.  * The page table must be locked and interrupts must be disabled.
  169.  *
  170.  * @param as Address space to which page belongs.
  171.  * @param page Virtual address of the page to be mapped.
  172.  * @param frame Physical address of memory frame to which the mapping is done.
  173.  * @param flags Flags to be used for mapping.
  174.  */
  175. void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags)
  176. {
  177.     pte_t *t;
  178.     unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) };
  179.    
  180.     if (!hash_table_find(&page_ht, key)) {
  181.         t = (pte_t *) malloc(sizeof(pte_t), FRAME_ATOMIC);
  182.         ASSERT(t != NULL);
  183.  
  184.         t->g = (flags & PAGE_GLOBAL) != 0;
  185.         t->x = (flags & PAGE_EXEC) != 0;
  186.         t->w = (flags & PAGE_WRITE) != 0;
  187.         t->k = !(flags & PAGE_USER);
  188.         t->c = (flags & PAGE_CACHEABLE) != 0;
  189.         t->p = !(flags & PAGE_NOT_PRESENT);
  190.  
  191.         t->as = as;
  192.         t->page = ALIGN_DOWN(page, PAGE_SIZE);
  193.         t->frame = ALIGN_DOWN(frame, FRAME_SIZE);
  194.  
  195.         hash_table_insert(&page_ht, key, &t->link);
  196.     }
  197. }
  198.  
  199. /** Remove mapping of page from page hash table.
  200.  *
  201.  * Remove any mapping of page within address space as.
  202.  * TLB shootdown should follow in order to make effects of
  203.  * this call visible.
  204.  *
  205.  * The page table must be locked and interrupts must be disabled.
  206.  *
  207.  * @param as Address space to wich page belongs.
  208.  * @param page Virtual address of the page to be demapped.
  209.  */
  210. void ht_mapping_remove(as_t *as, uintptr_t page)
  211. {
  212.     unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) };
  213.    
  214.     /*
  215.      * Note that removed PTE's will be freed
  216.      * by remove_callback().
  217.      */
  218.     hash_table_remove(&page_ht, key, 2);
  219. }
  220.  
  221.  
  222. /** Find mapping for virtual page in page hash table.
  223.  *
  224.  * Find mapping for virtual page.
  225.  *
  226.  * The page table must be locked and interrupts must be disabled.
  227.  *
  228.  * @param as Address space to wich page belongs.
  229.  * @param page Virtual page.
  230.  *
  231.  * @return NULL if there is no such mapping; requested mapping otherwise.
  232.  */
  233. pte_t *ht_mapping_find(as_t *as, uintptr_t page)
  234. {
  235.     link_t *hlp;
  236.     pte_t *t = NULL;
  237.     unative_t key[2] = { (uintptr_t) as, page = ALIGN_DOWN(page, PAGE_SIZE) };
  238.    
  239.     hlp = hash_table_find(&page_ht, key);
  240.     if (hlp)
  241.         t = hash_table_get_instance(hlp, pte_t, link);
  242.  
  243.     return t;
  244. }
  245.  
  246. /** @}
  247.  */
  248.