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  1. /*
  2.  * Copyright (C) 2001-2006 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. /*
  30.  * This file contains address space manipulation functions.
  31.  * Roughly speaking, this is a higher-level client of
  32.  * Virtual Address Translation (VAT) subsystem.
  33.  */
  34.  
  35. #include <mm/as.h>
  36. #include <arch/mm/as.h>
  37. #include <mm/page.h>
  38. #include <mm/frame.h>
  39. #include <mm/tlb.h>
  40. #include <mm/heap.h>
  41. #include <arch/mm/page.h>
  42. #include <genarch/mm/page_pt.h>
  43. #include <mm/asid.h>
  44. #include <arch/mm/asid.h>
  45. #include <arch/types.h>
  46. #include <typedefs.h>
  47. #include <synch/spinlock.h>
  48. #include <config.h>
  49. #include <list.h>
  50. #include <panic.h>
  51. #include <arch/asm.h>
  52. #include <debug.h>
  53. #include <memstr.h>
  54. #include <arch.h>
  55. #include <print.h>
  56.  
  57. as_operations_t *as_operations = NULL;
  58.  
  59. /** Kernel address space. */
  60. as_t *AS_KERNEL = NULL;
  61.  
  62. static int get_area_flags(as_area_t *a);
  63.  
  64. /** Initialize address space subsystem. */
  65. void as_init(void)
  66. {
  67.     as_arch_init();
  68.     AS_KERNEL = as_create(FLAG_AS_KERNEL | FLAG_AS_EARLYMALLOC);
  69.         if (!AS_KERNEL)
  70.                 panic("can't create kernel address space\n");
  71. }
  72.  
  73. /** Create address space.
  74.  *
  75.  * @param flags Flags that influence way in wich the address space is created.
  76.  */
  77. as_t *as_create(int flags)
  78. {
  79.     as_t *as;
  80.  
  81.     if (flags & FLAG_AS_EARLYMALLOC)
  82.         as = (as_t *) early_malloc(sizeof(as_t));
  83.     else
  84.         as = (as_t *) malloc(sizeof(as_t));
  85.     if (as) {
  86.         list_initialize(&as->as_with_asid_link);
  87.         spinlock_initialize(&as->lock, "as_lock");
  88.         list_initialize(&as->as_area_head);
  89.  
  90.         if (flags & FLAG_AS_KERNEL)
  91.             as->asid = ASID_KERNEL;
  92.         else
  93.             as->asid = ASID_INVALID;
  94.  
  95.         as->page_table = page_table_create(flags);
  96.     }
  97.  
  98.     return as;
  99. }
  100.  
  101. /** Create address space area of common attributes.
  102.  *
  103.  * The created address space area is added to the target address space.
  104.  *
  105.  * @param as Target address space.
  106.  * @param type Type of area.
  107.  * @param size Size of area in multiples of PAGE_SIZE.
  108.  * @param base Base address of area.
  109.  *
  110.  * @return Address space area on success or NULL on failure.
  111.  */
  112. as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
  113. {
  114.     ipl_t ipl;
  115.     as_area_t *a;
  116.    
  117.     if (base % PAGE_SIZE)
  118.         panic("addr not aligned to a page boundary");
  119.    
  120.     ipl = interrupts_disable();
  121.     spinlock_lock(&as->lock);
  122.    
  123.     /*
  124.      * TODO: test as_area which is to be created doesn't overlap with an existing one.
  125.      */
  126.    
  127.     a = (as_area_t *) malloc(sizeof(as_area_t));
  128.     if (a) {   
  129.         spinlock_initialize(&a->lock, "as_area_lock");
  130.            
  131.         link_initialize(&a->link);         
  132.         a->type = type;
  133.         a->size = size;
  134.         a->base = base;
  135.        
  136.         list_append(&a->link, &as->as_area_head);
  137.     }
  138.  
  139.     spinlock_unlock(&as->lock);
  140.     interrupts_restore(ipl);
  141.  
  142.     return a;
  143. }
  144.  
  145. /** Initialize mapping for one page of address space.
  146.  *
  147.  * This functions maps 'page' to 'frame' according
  148.  * to attributes of the address space area to
  149.  * wich 'page' belongs.
  150.  *
  151.  * @param a Target address space.
  152.  * @param page Virtual page within the area.
  153.  * @param frame Physical frame to which page will be mapped.
  154.  */
  155. void as_set_mapping(as_t *as, __address page, __address frame)
  156. {
  157.     as_area_t *a, *area = NULL;
  158.     link_t *cur;
  159.     ipl_t ipl;
  160.    
  161.     ipl = interrupts_disable();
  162.     spinlock_lock(&as->lock);
  163.    
  164.     /*
  165.      * First, try locate an area.
  166.      */
  167.     for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
  168.         a = list_get_instance(cur, as_area_t, link);
  169.         spinlock_lock(&a->lock);
  170.  
  171.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  172.             area = a;
  173.             break;
  174.         }
  175.        
  176.         spinlock_unlock(&a->lock);
  177.     }
  178.    
  179.     if (!area) {
  180.         panic("page not part of any as_area\n");
  181.     }
  182.  
  183.     /*
  184.      * Note: area->lock is held.
  185.      */
  186.    
  187.     page_mapping_insert(as, page, frame, get_area_flags(area));
  188.    
  189.     spinlock_unlock(&area->lock);
  190.     spinlock_unlock(&as->lock);
  191.     interrupts_restore(ipl);
  192. }
  193.  
  194. /** Handle page fault within the current address space.
  195.  *
  196.  * This is the high-level page fault handler.
  197.  * Interrupts are assumed disabled.
  198.  *
  199.  * @param page Faulting page.
  200.  *
  201.  * @return 0 on page fault, 1 on success.
  202.  */
  203. int as_page_fault(__address page)
  204. {
  205.     link_t *cur;
  206.     as_area_t *a, *area = NULL;
  207.     __address frame;
  208.    
  209.     ASSERT(AS);
  210.     spinlock_lock(&AS->lock);
  211.    
  212.     /*
  213.      * Search this areas of this address space for presence of 'page'.
  214.      */
  215.     for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
  216.         a = list_get_instance(cur, as_area_t, link);
  217.         spinlock_lock(&a->lock);
  218.  
  219.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  220.  
  221.             /*
  222.              * We found the area containing 'page'.
  223.              * TODO: access checking
  224.              */
  225.             area = a;
  226.             break;
  227.         }
  228.        
  229.         spinlock_unlock(&a->lock);
  230.     }
  231.    
  232.     if (!area) {
  233.         /*
  234.          * No area contained mapping for 'page'.
  235.          * Signal page fault to low-level handler.
  236.          */
  237.         spinlock_unlock(&AS->lock);
  238.         return 0;
  239.     }
  240.  
  241.     /*
  242.      * Note: area->lock is held.
  243.      */
  244.    
  245.     /*
  246.      * In general, there can be several reasons that
  247.      * can have caused this fault.
  248.      *
  249.      * - non-existent mapping: the area is a scratch
  250.      *   area (e.g. stack) and so far has not been
  251.      *   allocated a frame for the faulting page
  252.      *
  253.      * - non-present mapping: another possibility,
  254.      *   currently not implemented, would be frame
  255.      *   reuse; when this becomes a possibility,
  256.      *   do not forget to distinguish between
  257.      *   the different causes
  258.      */
  259.     frame = frame_alloc(0, ONE_FRAME, NULL, NULL);
  260.     memsetb(PA2KA(frame), FRAME_SIZE, 0);
  261.    
  262.     /*
  263.      * Map 'page' to 'frame'.
  264.      * Note that TLB shootdown is not attempted as only new information is being
  265.      * inserted into page tables.
  266.      */
  267.     page_mapping_insert(AS, page, frame, get_area_flags(area));
  268.    
  269.     spinlock_unlock(&area->lock);
  270.     spinlock_unlock(&AS->lock);
  271.  
  272.     return 1;
  273. }
  274.  
  275. /** Install address space on CPU.
  276.  *
  277.  * @param as Address space.
  278.  */
  279. void as_install(as_t *as)
  280. {
  281.     ipl_t ipl;
  282.    
  283.     asid_install(as);
  284.    
  285.     ipl = interrupts_disable();
  286.     spinlock_lock(&as->lock);
  287.     ASSERT(as->page_table);
  288.     SET_PTL0_ADDRESS(as->page_table);
  289.     spinlock_unlock(&as->lock);
  290.     interrupts_restore(ipl);
  291.  
  292.     /*
  293.      * Perform architecture-specific steps.
  294.      * (e.g. write ASID to hardware register etc.)
  295.      */
  296.     as_install_arch(as);
  297.    
  298.     AS = as;
  299. }
  300.  
  301. /** Compute flags for virtual address translation subsytem.
  302.  *
  303.  * The address space area must be locked.
  304.  * Interrupts must be disabled.
  305.  *
  306.  * @param a Address space area.
  307.  *
  308.  * @return Flags to be used in page_mapping_insert().
  309.  */
  310. int get_area_flags(as_area_t *a)
  311. {
  312.     int flags;
  313.  
  314.     switch (a->type) {
  315.         case AS_AREA_TEXT:
  316.             flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  317.             break;
  318.         case AS_AREA_DATA:
  319.         case AS_AREA_STACK:
  320.             flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  321.             break;
  322.         default:
  323.             panic("unexpected as_area_type_t %d", a->type);
  324.     }
  325.    
  326.     return flags;
  327. }
  328.  
  329. /** Create page table.
  330.  *
  331.  * Depending on architecture, create either address space
  332.  * private or global page table.
  333.  *
  334.  * @param flags Flags saying whether the page table is for kernel address space.
  335.  *
  336.  * @return First entry of the page table.
  337.  */
  338. pte_t *page_table_create(int flags)
  339. {
  340.         ASSERT(as_operations);
  341.         ASSERT(as_operations->page_table_create);
  342.  
  343.         return as_operations->page_table_create(flags);
  344. }
  345.