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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 for hierarchical 4-level page tables.
  36.  */
  37.  
  38. #include <genarch/mm/page_pt.h>
  39. #include <mm/page.h>
  40. #include <mm/frame.h>
  41. #include <mm/as.h>
  42. #include <arch/mm/page.h>
  43. #include <arch/mm/as.h>
  44. #include <arch/types.h>
  45. #include <typedefs.h>
  46. #include <arch/asm.h>
  47. #include <memstr.h>
  48.  
  49. static void pt_mapping_insert(as_t *as, __address page, __address frame, int flags);
  50. static void pt_mapping_remove(as_t *as, __address page);
  51. static pte_t *pt_mapping_find(as_t *as, __address page);
  52.  
  53. page_mapping_operations_t pt_mapping_operations = {
  54.     .mapping_insert = pt_mapping_insert,
  55.     .mapping_remove = pt_mapping_remove,
  56.     .mapping_find = pt_mapping_find
  57. };
  58.  
  59. /** Map page to frame using hierarchical page tables.
  60.  *
  61.  * Map virtual address page to physical address frame
  62.  * using flags.
  63.  *
  64.  * The page table must be locked and interrupts must be disabled.
  65.  *
  66.  * @param as Address space to wich page belongs.
  67.  * @param page Virtual address of the page to be mapped.
  68.  * @param frame Physical address of memory frame to which the mapping is done.
  69.  * @param flags Flags to be used for mapping.
  70.  */
  71. void pt_mapping_insert(as_t *as, __address page, __address frame, int flags)
  72. {
  73.     pte_t *ptl0, *ptl1, *ptl2, *ptl3;
  74.     __address newpt;
  75.  
  76.     ptl0 = (pte_t *) PA2KA((__address) as->page_table);
  77.  
  78.     if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
  79.         newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
  80.         memsetb(newpt, PAGE_SIZE, 0);
  81.         SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
  82.         SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
  83.     }
  84.  
  85.     ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
  86.  
  87.     if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
  88.         newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
  89.         memsetb(newpt, PAGE_SIZE, 0);
  90.         SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
  91.         SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
  92.     }
  93.  
  94.     ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
  95.  
  96.     if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {
  97.         newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
  98.         memsetb(newpt, PAGE_SIZE, 0);
  99.         SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
  100.         SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
  101.     }
  102.  
  103.     ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
  104.  
  105.     SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);
  106.     SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags);
  107. }
  108.  
  109. /** Remove mapping of page from hierarchical page tables.
  110.  *
  111.  * Remove any mapping of page within address space as.
  112.  * TLB shootdown should follow in order to make effects of
  113.  * this call visible.
  114.  *
  115.  * Empty page tables except PTL0 are freed.
  116.  *
  117.  * The page table must be locked and interrupts must be disabled.
  118.  *
  119.  * @param as Address space to wich page belongs.
  120.  * @param page Virtual address of the page to be demapped.
  121.  */
  122. void pt_mapping_remove(as_t *as, __address page)
  123. {
  124.     pte_t *ptl0, *ptl1, *ptl2, *ptl3;
  125.     bool empty = true;
  126.     int i;
  127.  
  128.     /*
  129.      * First, remove the mapping, if it exists.
  130.      */
  131.  
  132.     ptl0 = (pte_t *) PA2KA((__address) as->page_table);
  133.  
  134.     if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
  135.         return;
  136.  
  137.     ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
  138.  
  139.     if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
  140.         return;
  141.  
  142.     ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
  143.  
  144.     if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
  145.         return;
  146.  
  147.     ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
  148.  
  149.     /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */
  150.     memsetb((__address) &ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
  151.  
  152.     /*
  153.      * Second, free all empty tables along the way from PTL3 down to PTL0.
  154.      */
  155.    
  156.     /* check PTL3 */
  157.     for (i = 0; i < PTL3_ENTRIES; i++) {
  158.         if (PTE_VALID(&ptl3[i])) {
  159.             empty = false;
  160.             break;
  161.         }
  162.     }
  163.     if (empty) {
  164.         /*
  165.          * PTL3 is empty.
  166.          * Release the frame and remove PTL3 pointer from preceding table.
  167.          */
  168.         frame_free(ADDR2PFN(KA2PA((__address) ptl3)));
  169.         if (PTL2_ENTRIES)
  170.             memsetb((__address) &ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
  171.         else if (PTL1_ENTRIES)
  172.             memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
  173.         else
  174.             memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
  175.     } else {
  176.         /*
  177.          * PTL3 is not empty.
  178.          * Therefore, there must be a path from PTL0 to PTL3 and
  179.          * thus nothing to free in higher levels.
  180.          */
  181.         return;
  182.     }
  183.    
  184.     /* check PTL2, empty is still true */
  185.     if (PTL2_ENTRIES) {
  186.         for (i = 0; i < PTL2_ENTRIES; i++) {
  187.             if (PTE_VALID(&ptl2[i])) {
  188.                 empty = false;
  189.                 break;
  190.             }
  191.         }
  192.         if (empty) {
  193.             /*
  194.              * PTL2 is empty.
  195.              * Release the frame and remove PTL2 pointer from preceding table.
  196.              */
  197.             frame_free(ADDR2PFN(KA2PA((__address) ptl2)));
  198.             if (PTL1_ENTRIES)
  199.                 memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
  200.             else
  201.                 memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
  202.         }
  203.         else {
  204.             /*
  205.              * PTL2 is not empty.
  206.              * Therefore, there must be a path from PTL0 to PTL2 and
  207.              * thus nothing to free in higher levels.
  208.              */
  209.             return;
  210.         }
  211.     }
  212.  
  213.     /* check PTL1, empty is still true */
  214.     if (PTL1_ENTRIES) {
  215.         for (i = 0; i < PTL1_ENTRIES; i++) {
  216.             if (PTE_VALID(&ptl1[i])) {
  217.                 empty = false;
  218.                 break;
  219.             }
  220.         }
  221.         if (empty) {
  222.             /*
  223.              * PTL1 is empty.
  224.              * Release the frame and remove PTL1 pointer from preceding table.
  225.              */
  226.             frame_free(ADDR2PFN(KA2PA((__address) ptl1)));
  227.             memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
  228.         }
  229.     }
  230.  
  231. }
  232.  
  233. /** Find mapping for virtual page in hierarchical page tables.
  234.  *
  235.  * Find mapping for virtual page.
  236.  *
  237.  * The page table must be locked and interrupts must be disabled.
  238.  *
  239.  * @param as Address space to which page belongs.
  240.  * @param page Virtual page.
  241.  *
  242.  * @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise.
  243.  */
  244. pte_t *pt_mapping_find(as_t *as, __address page)
  245. {
  246.     pte_t *ptl0, *ptl1, *ptl2, *ptl3;
  247.  
  248.     ptl0 = (pte_t *) PA2KA((__address) as->page_table);
  249.  
  250.     if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
  251.         return NULL;
  252.  
  253.     ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
  254.  
  255.     if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
  256.         return NULL;
  257.  
  258.     ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
  259.  
  260.     if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
  261.         return NULL;
  262.  
  263.     ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
  264.  
  265.     return &ptl3[PTL3_INDEX(page)];
  266. }
  267.  
  268.  /** @}
  269.  */
  270.  
  271.