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