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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/slab.h>
  40. #include <mm/tlb.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 <adt/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);
  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.     as = (as_t *) malloc(sizeof(as_t));
  82.     if (as) {
  83.         list_initialize(&as->as_with_asid_link);
  84.         spinlock_initialize(&as->lock, "as_lock");
  85.         list_initialize(&as->as_area_head);
  86.  
  87.         if (flags & FLAG_AS_KERNEL)
  88.             as->asid = ASID_KERNEL;
  89.         else
  90.             as->asid = ASID_INVALID;
  91.  
  92.         as->page_table = page_table_create(flags);
  93.     }
  94.  
  95.     return as;
  96. }
  97.  
  98. /** Create address space area of common attributes.
  99.  *
  100.  * The created address space area is added to the target address space.
  101.  *
  102.  * @param as Target address space.
  103.  * @param type Type of area.
  104.  * @param size Size of area in multiples of PAGE_SIZE.
  105.  * @param base Base address of area.
  106.  *
  107.  * @return Address space area on success or NULL on failure.
  108.  */
  109. as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
  110. {
  111.     ipl_t ipl;
  112.     as_area_t *a;
  113.    
  114.     if (base % PAGE_SIZE)
  115.         panic("addr not aligned to a page boundary");
  116.    
  117.     ipl = interrupts_disable();
  118.     spinlock_lock(&as->lock);
  119.    
  120.     /*
  121.      * TODO: test as_area which is to be created doesn't overlap with an existing one.
  122.      */
  123.    
  124.     a = (as_area_t *) malloc(sizeof(as_area_t));
  125.     if (a) {   
  126.         spinlock_initialize(&a->lock, "as_area_lock");
  127.            
  128.         link_initialize(&a->link);         
  129.         a->type = type;
  130.         a->size = size;
  131.         a->base = base;
  132.        
  133.         list_append(&a->link, &as->as_area_head);
  134.     }
  135.  
  136.     spinlock_unlock(&as->lock);
  137.     interrupts_restore(ipl);
  138.  
  139.     return a;
  140. }
  141.  
  142. /** Initialize mapping for one page of address space.
  143.  *
  144.  * This functions maps 'page' to 'frame' according
  145.  * to attributes of the address space area to
  146.  * wich 'page' belongs.
  147.  *
  148.  * @param a Target address space.
  149.  * @param page Virtual page within the area.
  150.  * @param frame Physical frame to which page will be mapped.
  151.  */
  152. void as_set_mapping(as_t *as, __address page, __address frame)
  153. {
  154.     as_area_t *a, *area = NULL;
  155.     link_t *cur;
  156.     ipl_t ipl;
  157.    
  158.     ipl = interrupts_disable();
  159.     spinlock_lock(&as->lock);
  160.    
  161.     /*
  162.      * First, try locate an area.
  163.      */
  164.     for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
  165.         a = list_get_instance(cur, as_area_t, link);
  166.         spinlock_lock(&a->lock);
  167.  
  168.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  169.             area = a;
  170.             break;
  171.         }
  172.        
  173.         spinlock_unlock(&a->lock);
  174.     }
  175.    
  176.     if (!area) {
  177.         panic("page not part of any as_area\n");
  178.     }
  179.  
  180.     /*
  181.      * Note: area->lock is held.
  182.      */
  183.    
  184.     page_mapping_insert(as, page, frame, get_area_flags(area));
  185.    
  186.     spinlock_unlock(&area->lock);
  187.     spinlock_unlock(&as->lock);
  188.     interrupts_restore(ipl);
  189. }
  190.  
  191. /** Handle page fault within the current address space.
  192.  *
  193.  * This is the high-level page fault handler.
  194.  * Interrupts are assumed disabled.
  195.  *
  196.  * @param page Faulting page.
  197.  *
  198.  * @return 0 on page fault, 1 on success.
  199.  */
  200. int as_page_fault(__address page)
  201. {
  202.     link_t *cur;
  203.     as_area_t *a, *area = NULL;
  204.     __address frame;
  205.    
  206.     ASSERT(AS);
  207.     spinlock_lock(&AS->lock);
  208.    
  209.     /*
  210.      * Search this areas of this address space for presence of 'page'.
  211.      */
  212.     for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
  213.         a = list_get_instance(cur, as_area_t, link);
  214.         spinlock_lock(&a->lock);
  215.  
  216.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  217.  
  218.             /*
  219.              * We found the area containing 'page'.
  220.              * TODO: access checking
  221.              */
  222.             area = a;
  223.             break;
  224.         }
  225.        
  226.         spinlock_unlock(&a->lock);
  227.     }
  228.    
  229.     if (!area) {
  230.         /*
  231.          * No area contained mapping for 'page'.
  232.          * Signal page fault to low-level handler.
  233.          */
  234.         spinlock_unlock(&AS->lock);
  235.         return 0;
  236.     }
  237.  
  238.     /*
  239.      * Note: area->lock is held.
  240.      */
  241.    
  242.     /*
  243.      * In general, there can be several reasons that
  244.      * can have caused this fault.
  245.      *
  246.      * - non-existent mapping: the area is a scratch
  247.      *   area (e.g. stack) and so far has not been
  248.      *   allocated a frame for the faulting page
  249.      *
  250.      * - non-present mapping: another possibility,
  251.      *   currently not implemented, would be frame
  252.      *   reuse; when this becomes a possibility,
  253.      *   do not forget to distinguish between
  254.      *   the different causes
  255.      */
  256.     frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
  257.     memsetb(PA2KA(frame), FRAME_SIZE, 0);
  258.    
  259.     /*
  260.      * Map 'page' to 'frame'.
  261.      * Note that TLB shootdown is not attempted as only new information is being
  262.      * inserted into page tables.
  263.      */
  264.     page_mapping_insert(AS, page, frame, get_area_flags(area));
  265.    
  266.     spinlock_unlock(&area->lock);
  267.     spinlock_unlock(&AS->lock);
  268.  
  269.     return 1;
  270. }
  271.  
  272. /** Install address space on CPU.
  273.  *
  274.  * @param as Address space.
  275.  */
  276. void as_install(as_t *as)
  277. {
  278.     ipl_t ipl;
  279.    
  280.     asid_install(as);
  281.    
  282.     ipl = interrupts_disable();
  283.     spinlock_lock(&as->lock);
  284.     SET_PTL0_ADDRESS(as->page_table);
  285.     spinlock_unlock(&as->lock);
  286.     interrupts_restore(ipl);
  287.  
  288.     /*
  289.      * Perform architecture-specific steps.
  290.      * (e.g. write ASID to hardware register etc.)
  291.      */
  292.     as_install_arch(as);
  293.    
  294.     AS = as;
  295. }
  296.  
  297. /** Compute flags for virtual address translation subsytem.
  298.  *
  299.  * The address space area must be locked.
  300.  * Interrupts must be disabled.
  301.  *
  302.  * @param a Address space area.
  303.  *
  304.  * @return Flags to be used in page_mapping_insert().
  305.  */
  306. int get_area_flags(as_area_t *a)
  307. {
  308.     int flags;
  309.  
  310.     switch (a->type) {
  311.         case AS_AREA_TEXT:
  312.             flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  313.             break;
  314.         case AS_AREA_DATA:
  315.         case AS_AREA_STACK:
  316.             flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  317.             break;
  318.         default:
  319.             panic("unexpected as_area_type_t %d", a->type);
  320.     }
  321.    
  322.     return flags;
  323. }
  324.  
  325. /** Create page table.
  326.  *
  327.  * Depending on architecture, create either address space
  328.  * private or global page table.
  329.  *
  330.  * @param flags Flags saying whether the page table is for kernel address space.
  331.  *
  332.  * @return First entry of the page table.
  333.  */
  334. pte_t *page_table_create(int flags)
  335. {
  336.         ASSERT(as_operations);
  337.         ASSERT(as_operations->page_table_create);
  338.  
  339.         return as_operations->page_table_create(flags);
  340. }
  341.