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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. /** Address space lock. It protects inactive_as_with_asid_head. */
  60. SPINLOCK_INITIALIZE(as_lock);
  61.  
  62. /**
  63.  * This list contains address spaces that are not active on any
  64.  * processor and that have valid ASID.
  65.  */
  66. LIST_INITIALIZE(inactive_as_with_asid_head);
  67.  
  68. /** Kernel address space. */
  69. as_t *AS_KERNEL = NULL;
  70.  
  71. static int get_area_flags(as_area_t *a);
  72.  
  73. /** Initialize address space subsystem. */
  74. void as_init(void)
  75. {
  76.     as_arch_init();
  77.     AS_KERNEL = as_create(FLAG_AS_KERNEL);
  78.         if (!AS_KERNEL)
  79.                 panic("can't create kernel address space\n");
  80. }
  81.  
  82. /** Create address space.
  83.  *
  84.  * @param flags Flags that influence way in wich the address space is created.
  85.  */
  86. as_t *as_create(int flags)
  87. {
  88.     as_t *as;
  89.  
  90.     as = (as_t *) malloc(sizeof(as_t), 0);
  91.     link_initialize(&as->inactive_as_with_asid_link);
  92.     spinlock_initialize(&as->lock, "as_lock");
  93.     list_initialize(&as->as_area_head);
  94.    
  95.     if (flags & FLAG_AS_KERNEL)
  96.         as->asid = ASID_KERNEL;
  97.     else
  98.         as->asid = ASID_INVALID;
  99.    
  100.     as->refcount = 0;
  101.     as->page_table = page_table_create(flags);
  102.  
  103.     return as;
  104. }
  105.  
  106. /** Free Adress space */
  107. void as_free(as_t *as)
  108. {
  109.     ASSERT(as->refcount == 0);
  110.  
  111.     /* TODO: free as_areas and other resources held by as */
  112.     /* TODO: free page table */
  113.     free(as);
  114. }
  115.  
  116. /** Create address space area of common attributes.
  117.  *
  118.  * The created address space area is added to the target address space.
  119.  *
  120.  * @param as Target address space.
  121.  * @param type Type of area.
  122.  * @param size Size of area in multiples of PAGE_SIZE.
  123.  * @param base Base address of area.
  124.  *
  125.  * @return Address space area on success or NULL on failure.
  126.  */
  127. as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
  128. {
  129.     ipl_t ipl;
  130.     as_area_t *a;
  131.    
  132.     if (base % PAGE_SIZE)
  133.         panic("addr not aligned to a page boundary");
  134.    
  135.     ipl = interrupts_disable();
  136.     spinlock_lock(&as->lock);
  137.    
  138.     /*
  139.      * TODO: test as_area which is to be created doesn't overlap with an existing one.
  140.      */
  141.    
  142.     a = (as_area_t *) malloc(sizeof(as_area_t), 0);
  143.  
  144.     spinlock_initialize(&a->lock, "as_area_lock");
  145.    
  146.     link_initialize(&a->link);         
  147.     a->type = type;
  148.     a->size = size;
  149.     a->base = base;
  150.    
  151.     list_append(&a->link, &as->as_area_head);
  152.  
  153.     spinlock_unlock(&as->lock);
  154.     interrupts_restore(ipl);
  155.  
  156.     return a;
  157. }
  158.  
  159. /** Initialize mapping for one page of address space.
  160.  *
  161.  * This functions maps 'page' to 'frame' according
  162.  * to attributes of the address space area to
  163.  * wich 'page' belongs.
  164.  *
  165.  * @param as Target address space.
  166.  * @param page Virtual page within the area.
  167.  * @param frame Physical frame to which page will be mapped.
  168.  */
  169. void as_set_mapping(as_t *as, __address page, __address frame)
  170. {
  171.     as_area_t *a, *area = NULL;
  172.     link_t *cur;
  173.     ipl_t ipl;
  174.    
  175.     ipl = interrupts_disable();
  176.     spinlock_lock(&as->lock);
  177.    
  178.     /*
  179.      * First, try locate an area.
  180.      */
  181.     for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
  182.         a = list_get_instance(cur, as_area_t, link);
  183.         spinlock_lock(&a->lock);
  184.  
  185.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  186.             area = a;
  187.             break;
  188.         }
  189.        
  190.         spinlock_unlock(&a->lock);
  191.     }
  192.    
  193.     if (!area) {
  194.         panic("page not part of any as_area\n");
  195.     }
  196.  
  197.     /*
  198.      * Note: area->lock is held.
  199.      */
  200.    
  201.     page_mapping_insert(as, page, frame, get_area_flags(area));
  202.    
  203.     spinlock_unlock(&area->lock);
  204.     spinlock_unlock(&as->lock);
  205.     interrupts_restore(ipl);
  206. }
  207.  
  208. /** Handle page fault within the current address space.
  209.  *
  210.  * This is the high-level page fault handler.
  211.  * Interrupts are assumed disabled.
  212.  *
  213.  * @param page Faulting page.
  214.  *
  215.  * @return 0 on page fault, 1 on success.
  216.  */
  217. int as_page_fault(__address page)
  218. {
  219.     link_t *cur;
  220.     as_area_t *a, *area = NULL;
  221.     __address frame;
  222.    
  223.     ASSERT(AS);
  224.     spinlock_lock(&AS->lock);
  225.    
  226.     /*
  227.      * Search this areas of this address space for presence of 'page'.
  228.      */
  229.     for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
  230.         a = list_get_instance(cur, as_area_t, link);
  231.         spinlock_lock(&a->lock);
  232.  
  233.         if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
  234.  
  235.             /*
  236.              * We found the area containing 'page'.
  237.              * TODO: access checking
  238.              */
  239.             area = a;
  240.             break;
  241.         }
  242.        
  243.         spinlock_unlock(&a->lock);
  244.     }
  245.    
  246.     if (!area) {
  247.         /*
  248.          * No area contained mapping for 'page'.
  249.          * Signal page fault to low-level handler.
  250.          */
  251.         spinlock_unlock(&AS->lock);
  252.         return 0;
  253.     }
  254.  
  255.     /*
  256.      * Note: area->lock is held.
  257.      */
  258.    
  259.     /*
  260.      * In general, there can be several reasons that
  261.      * can have caused this fault.
  262.      *
  263.      * - non-existent mapping: the area is a scratch
  264.      *   area (e.g. stack) and so far has not been
  265.      *   allocated a frame for the faulting page
  266.      *
  267.      * - non-present mapping: another possibility,
  268.      *   currently not implemented, would be frame
  269.      *   reuse; when this becomes a possibility,
  270.      *   do not forget to distinguish between
  271.      *   the different causes
  272.      */
  273.     frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
  274.     memsetb(PA2KA(frame), FRAME_SIZE, 0);
  275.    
  276.     /*
  277.      * Map 'page' to 'frame'.
  278.      * Note that TLB shootdown is not attempted as only new information is being
  279.      * inserted into page tables.
  280.      */
  281.     page_mapping_insert(AS, page, frame, get_area_flags(area));
  282.    
  283.     spinlock_unlock(&area->lock);
  284.     spinlock_unlock(&AS->lock);
  285.  
  286.     return 1;
  287. }
  288.  
  289. /** Switch address spaces.
  290.  *
  291.  * @param old Old address space or NULL.
  292.  * @param new New address space.
  293.  */
  294. void as_switch(as_t *old, as_t *new)
  295. {
  296.     ipl_t ipl;
  297.     bool needs_asid = false;
  298.    
  299.     ipl = interrupts_disable();
  300.     spinlock_lock(&as_lock);
  301.  
  302.     /*
  303.      * First, take care of the old address space.
  304.      */
  305.     if (old) {
  306.         spinlock_lock(&old->lock);
  307.         ASSERT(old->refcount);
  308.         if((--old->refcount == 0) && (old != AS_KERNEL)) {
  309.             /*
  310.              * The old address space is no longer active on
  311.              * any processor. It can be appended to the
  312.              * list of inactive address spaces with assigned
  313.              * ASID.
  314.              */
  315.              ASSERT(old->asid != ASID_INVALID);
  316.              list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
  317.         }
  318.         spinlock_unlock(&old->lock);
  319.     }
  320.  
  321.     /*
  322.      * Second, prepare the new address space.
  323.      */
  324.     spinlock_lock(&new->lock);
  325.     if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
  326.         if (new->asid != ASID_INVALID)
  327.             list_remove(&new->inactive_as_with_asid_link);
  328.         else
  329.             needs_asid = true;  /* defer call to asid_get() until new->lock is released */
  330.     }
  331.     SET_PTL0_ADDRESS(new->page_table);
  332.     spinlock_unlock(&new->lock);
  333.  
  334.     if (needs_asid) {
  335.         /*
  336.          * Allocation of new ASID was deferred
  337.          * until now in order to avoid deadlock.
  338.          */
  339.         asid_t asid;
  340.        
  341.         asid = asid_get();
  342.         spinlock_lock(&new->lock);
  343.         new->asid = asid;
  344.         spinlock_unlock(&new->lock);
  345.     }
  346.     spinlock_unlock(&as_lock);
  347.     interrupts_restore(ipl);
  348.    
  349.     /*
  350.      * Perform architecture-specific steps.
  351.      * (e.g. write ASID to hardware register etc.)
  352.      */
  353.     as_install_arch(new);
  354.    
  355.     AS = new;
  356. }
  357.  
  358. /** Compute flags for virtual address translation subsytem.
  359.  *
  360.  * The address space area must be locked.
  361.  * Interrupts must be disabled.
  362.  *
  363.  * @param a Address space area.
  364.  *
  365.  * @return Flags to be used in page_mapping_insert().
  366.  */
  367. int get_area_flags(as_area_t *a)
  368. {
  369.     int flags;
  370.  
  371.     switch (a->type) {
  372.         case AS_AREA_TEXT:
  373.             flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  374.             break;
  375.         case AS_AREA_DATA:
  376.         case AS_AREA_STACK:
  377.             flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  378.             break;
  379.         default:
  380.             panic("unexpected as_area_type_t %d", a->type);
  381.     }
  382.    
  383.     return flags;
  384. }
  385.  
  386. /** Create page table.
  387.  *
  388.  * Depending on architecture, create either address space
  389.  * private or global page table.
  390.  *
  391.  * @param flags Flags saying whether the page table is for kernel address space.
  392.  *
  393.  * @return First entry of the page table.
  394.  */
  395. pte_t *page_table_create(int flags)
  396. {
  397.         ASSERT(as_operations);
  398.         ASSERT(as_operations->page_table_create);
  399.  
  400.         return as_operations->page_table_create(flags);
  401. }
  402.