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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 size_t hash(unative_t key[]);
  55. static bool compare(unative_t key[], size_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,
  59.     int flags);
  60. static void ht_mapping_remove(as_t *as, uintptr_t page);
  61. static pte_t *ht_mapping_find(as_t *as, uintptr_t page);
  62.  
  63. /**
  64.  * This lock protects the page hash table. It must be acquired
  65.  * after address space lock and after any address space area
  66.  * locks.
  67.  */
  68. mutex_t page_ht_lock;
  69.  
  70. /**
  71.  * Page hash table.
  72.  * The page hash table may be accessed only when page_ht_lock is held.
  73.  */
  74. hash_table_t page_ht;
  75.  
  76. /** Hash table operations for page hash table. */
  77. hash_table_operations_t ht_operations = {
  78.     .hash = hash,
  79.     .compare = compare,
  80.     .remove_callback = remove_callback
  81. };
  82.  
  83. /** Page mapping operations for page hash table architectures. */
  84. page_mapping_operations_t ht_mapping_operations = {
  85.     .mapping_insert = ht_mapping_insert,
  86.     .mapping_remove = ht_mapping_remove,
  87.     .mapping_find = ht_mapping_find
  88. };
  89.  
  90. /** Compute page hash table index.
  91.  *
  92.  * @param key Array of two keys (i.e. page and address space).
  93.  *
  94.  * @return Index into page hash table.
  95.  */
  96. size_t hash(unative_t key[])
  97. {
  98.     as_t *as = (as_t *) key[KEY_AS];
  99.     uintptr_t page = (uintptr_t) key[KEY_PAGE];
  100.     size_t index;
  101.    
  102.     /*
  103.      * Virtual page addresses have roughly the same probability
  104.      * of occurring. Least significant bits of VPN compose the
  105.      * hash index.
  106.      */
  107.     index = ((page >> PAGE_WIDTH) & (PAGE_HT_ENTRIES - 1));
  108.    
  109.     /*
  110.      * Address space structures are likely to be allocated from
  111.      * similar addresses. Least significant bits compose the
  112.      * hash index.
  113.      */
  114.     index |= ((unative_t) as) & (PAGE_HT_ENTRIES - 1);
  115.    
  116.     return index;
  117. }
  118.  
  119. /** Compare page hash table item with page and/or address space.
  120.  *
  121.  * @param key Array of one or two keys (i.e. page and/or address space).
  122.  * @param keys Number of keys passed.
  123.  * @param item Item to compare the keys with.
  124.  *
  125.  * @return true on match, false otherwise.
  126.  */
  127. bool compare(unative_t key[], size_t keys, link_t *item)
  128. {
  129.     pte_t *t;
  130.  
  131.     ASSERT(item);
  132.     ASSERT((keys > 0) && (keys <= PAGE_HT_KEYS));
  133.  
  134.     /*
  135.      * Convert item to PTE.
  136.      */
  137.     t = hash_table_get_instance(item, pte_t, link);
  138.  
  139.     if (keys == PAGE_HT_KEYS) {
  140.         return (key[KEY_AS] == (uintptr_t) t->as) &&
  141.             (key[KEY_PAGE] == t->page);
  142.     } else {
  143.         return (key[KEY_AS] == (uintptr_t) t->as);
  144.     }
  145. }
  146.  
  147. /** Callback on page hash table item removal.
  148.  *
  149.  * @param item Page hash table item being removed.
  150.  */
  151. void remove_callback(link_t *item)
  152. {
  153.     pte_t *t;
  154.  
  155.     ASSERT(item);
  156.  
  157.     /*
  158.      * Convert item to PTE.
  159.      */
  160.     t = hash_table_get_instance(item, pte_t, link);
  161.  
  162.     free(t);
  163. }
  164.  
  165. /** Map page to frame using page hash table.
  166.  *
  167.  * Map virtual address page to physical address frame
  168.  * using flags.
  169.  *
  170.  * The page table must be locked and interrupts must be disabled.
  171.  *
  172.  * @param as Address space to which page belongs.
  173.  * @param page Virtual address of the page to be mapped.
  174.  * @param frame Physical address of memory frame to which the mapping is done.
  175.  * @param flags Flags to be used for mapping.
  176.  */
  177. void ht_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags)
  178. {
  179.     pte_t *t;
  180.     unative_t key[2] = {
  181.         (uintptr_t) as,
  182.         page = ALIGN_DOWN(page, PAGE_SIZE)
  183.     };
  184.    
  185.     if (!hash_table_find(&page_ht, key)) {
  186.         t = (pte_t *) malloc(sizeof(pte_t), FRAME_ATOMIC);
  187.         ASSERT(t != NULL);
  188.  
  189.         t->g = (flags & PAGE_GLOBAL) != 0;
  190.         t->x = (flags & PAGE_EXEC) != 0;
  191.         t->w = (flags & PAGE_WRITE) != 0;
  192.         t->k = !(flags & PAGE_USER);
  193.         t->c = (flags & PAGE_CACHEABLE) != 0;
  194.         t->p = !(flags & PAGE_NOT_PRESENT);
  195.         t->a = false;
  196.         t->d = false;
  197.  
  198.         t->as = as;
  199.         t->page = ALIGN_DOWN(page, PAGE_SIZE);
  200.         t->frame = ALIGN_DOWN(frame, FRAME_SIZE);
  201.  
  202.         hash_table_insert(&page_ht, key, &t->link);
  203.     }
  204. }
  205.  
  206. /** Remove mapping of page from page hash table.
  207.  *
  208.  * Remove any mapping of page within address space as.
  209.  * TLB shootdown should follow in order to make effects of
  210.  * this call visible.
  211.  *
  212.  * The page table must be locked and interrupts must be disabled.
  213.  *
  214.  * @param as Address space to wich page belongs.
  215.  * @param page Virtual address of the page to be demapped.
  216.  */
  217. void ht_mapping_remove(as_t *as, uintptr_t page)
  218. {
  219.     unative_t key[2] = {
  220.         (uintptr_t) as,
  221.         page = ALIGN_DOWN(page, PAGE_SIZE)
  222.     };
  223.    
  224.     /*
  225.      * Note that removed PTE's will be freed
  226.      * by remove_callback().
  227.      */
  228.     hash_table_remove(&page_ht, key, 2);
  229. }
  230.  
  231.  
  232. /** Find mapping for virtual page in page hash table.
  233.  *
  234.  * Find mapping for virtual page.
  235.  *
  236.  * The page table must be locked and interrupts must be disabled.
  237.  *
  238.  * @param as Address space to wich page belongs.
  239.  * @param page Virtual page.
  240.  *
  241.  * @return NULL if there is no such mapping; requested mapping otherwise.
  242.  */
  243. pte_t *ht_mapping_find(as_t *as, uintptr_t page)
  244. {
  245.     link_t *hlp;
  246.     pte_t *t = NULL;
  247.     unative_t key[2] = {
  248.         (uintptr_t) as,
  249.         page = ALIGN_DOWN(page, PAGE_SIZE)
  250.     };
  251.    
  252.     hlp = hash_table_find(&page_ht, key);
  253.     if (hlp)
  254.         t = hash_table_get_instance(hlp, pte_t, link);
  255.  
  256.     return t;
  257. }
  258.  
  259. /** @}
  260.  */
  261.