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