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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. static as_area_t *find_area_and_lock(as_t *as, __address va);
  73.  
  74. /** Initialize address space subsystem. */
  75. void as_init(void)
  76. {
  77.     as_arch_init();
  78.     AS_KERNEL = as_create(FLAG_AS_KERNEL);
  79.         if (!AS_KERNEL)
  80.                 panic("can't create kernel address space\n");
  81. }
  82.  
  83. /** Create address space.
  84.  *
  85.  * @param flags Flags that influence way in wich the address space is created.
  86.  */
  87. as_t *as_create(int flags)
  88. {
  89.     as_t *as;
  90.  
  91.     as = (as_t *) malloc(sizeof(as_t), 0);
  92.     link_initialize(&as->inactive_as_with_asid_link);
  93.     spinlock_initialize(&as->lock, "as_lock");
  94.     list_initialize(&as->as_area_head);
  95.    
  96.     if (flags & FLAG_AS_KERNEL)
  97.         as->asid = ASID_KERNEL;
  98.     else
  99.         as->asid = ASID_INVALID;
  100.    
  101.     as->refcount = 0;
  102.     as->page_table = page_table_create(flags);
  103.  
  104.     return as;
  105. }
  106.  
  107. /** Free Adress space */
  108. void as_free(as_t *as)
  109. {
  110.     ASSERT(as->refcount == 0);
  111.  
  112.     /* TODO: free as_areas and other resources held by as */
  113.     /* TODO: free page table */
  114.     free(as);
  115. }
  116.  
  117. /** Create address space area of common attributes.
  118.  *
  119.  * The created address space area is added to the target address space.
  120.  *
  121.  * @param as Target address space.
  122.  * @param flags Flags of the area.
  123.  * @param size Size of area in multiples of PAGE_SIZE.
  124.  * @param base Base address of area.
  125.  *
  126.  * @return Address space area on success or NULL on failure.
  127.  */
  128. as_area_t *as_area_create(as_t *as, int flags, size_t size, __address base)
  129. {
  130.     ipl_t ipl;
  131.     as_area_t *a;
  132.    
  133.     if (base % PAGE_SIZE)
  134.         panic("addr not aligned to a page boundary");
  135.    
  136.     ipl = interrupts_disable();
  137.     spinlock_lock(&as->lock);
  138.    
  139.     /*
  140.      * TODO: test as_area which is to be created doesn't overlap with an existing one.
  141.      */
  142.    
  143.     a = (as_area_t *) malloc(sizeof(as_area_t), 0);
  144.  
  145.     spinlock_initialize(&a->lock, "as_area_lock");
  146.    
  147.     link_initialize(&a->link);         
  148.     a->flags = flags;
  149.     a->size = size;
  150.     a->base = base;
  151.    
  152.     list_append(&a->link, &as->as_area_head);
  153.  
  154.     spinlock_unlock(&as->lock);
  155.     interrupts_restore(ipl);
  156.  
  157.     return a;
  158. }
  159.  
  160. /** Initialize mapping for one page of address space.
  161.  *
  162.  * This functions maps 'page' to 'frame' according
  163.  * to attributes of the address space area to
  164.  * wich 'page' belongs.
  165.  *
  166.  * @param as Target address space.
  167.  * @param page Virtual page within the area.
  168.  * @param frame Physical frame to which page will be mapped.
  169.  */
  170. void as_set_mapping(as_t *as, __address page, __address frame)
  171. {
  172.     as_area_t *area;
  173.     ipl_t ipl;
  174.    
  175.     ipl = interrupts_disable();
  176.     spinlock_lock(&as->lock);
  177.    
  178.     area = find_area_and_lock(as, page);
  179.     if (!area) {
  180.         panic("page not part of any as_area\n");
  181.     }
  182.  
  183.     page_mapping_insert(as, page, frame, get_area_flags(area));
  184.    
  185.     spinlock_unlock(&area->lock);
  186.     spinlock_unlock(&as->lock);
  187.     interrupts_restore(ipl);
  188. }
  189.  
  190. /** Handle page fault within the current address space.
  191.  *
  192.  * This is the high-level page fault handler.
  193.  * Interrupts are assumed disabled.
  194.  *
  195.  * @param page Faulting page.
  196.  *
  197.  * @return 0 on page fault, 1 on success.
  198.  */
  199. int as_page_fault(__address page)
  200. {
  201.     as_area_t *area;
  202.     __address frame;
  203.    
  204.     ASSERT(AS);
  205.     spinlock_lock(&AS->lock);
  206.    
  207.     area = find_area_and_lock(AS, page);   
  208.     if (!area) {
  209.         /*
  210.          * No area contained mapping for 'page'.
  211.          * Signal page fault to low-level handler.
  212.          */
  213.         spinlock_unlock(&AS->lock);
  214.         return 0;
  215.     }
  216.  
  217.     /*
  218.      * In general, there can be several reasons that
  219.      * can have caused this fault.
  220.      *
  221.      * - non-existent mapping: the area is a scratch
  222.      *   area (e.g. stack) and so far has not been
  223.      *   allocated a frame for the faulting page
  224.      *
  225.      * - non-present mapping: another possibility,
  226.      *   currently not implemented, would be frame
  227.      *   reuse; when this becomes a possibility,
  228.      *   do not forget to distinguish between
  229.      *   the different causes
  230.      */
  231.     frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
  232.     memsetb(PA2KA(frame), FRAME_SIZE, 0);
  233.    
  234.     /*
  235.      * Map 'page' to 'frame'.
  236.      * Note that TLB shootdown is not attempted as only new information is being
  237.      * inserted into page tables.
  238.      */
  239.     page_mapping_insert(AS, page, frame, get_area_flags(area));
  240.    
  241.     spinlock_unlock(&area->lock);
  242.     spinlock_unlock(&AS->lock);
  243.  
  244.     return 1;
  245. }
  246.  
  247. /** Switch address spaces.
  248.  *
  249.  * @param old Old address space or NULL.
  250.  * @param new New address space.
  251.  */
  252. void as_switch(as_t *old, as_t *new)
  253. {
  254.     ipl_t ipl;
  255.     bool needs_asid = false;
  256.    
  257.     ipl = interrupts_disable();
  258.     spinlock_lock(&as_lock);
  259.  
  260.     /*
  261.      * First, take care of the old address space.
  262.      */
  263.     if (old) {
  264.         spinlock_lock(&old->lock);
  265.         ASSERT(old->refcount);
  266.         if((--old->refcount == 0) && (old != AS_KERNEL)) {
  267.             /*
  268.              * The old address space is no longer active on
  269.              * any processor. It can be appended to the
  270.              * list of inactive address spaces with assigned
  271.              * ASID.
  272.              */
  273.              ASSERT(old->asid != ASID_INVALID);
  274.              list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
  275.         }
  276.         spinlock_unlock(&old->lock);
  277.     }
  278.  
  279.     /*
  280.      * Second, prepare the new address space.
  281.      */
  282.     spinlock_lock(&new->lock);
  283.     if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
  284.         if (new->asid != ASID_INVALID)
  285.             list_remove(&new->inactive_as_with_asid_link);
  286.         else
  287.             needs_asid = true;  /* defer call to asid_get() until new->lock is released */
  288.     }
  289.     SET_PTL0_ADDRESS(new->page_table);
  290.     spinlock_unlock(&new->lock);
  291.  
  292.     if (needs_asid) {
  293.         /*
  294.          * Allocation of new ASID was deferred
  295.          * until now in order to avoid deadlock.
  296.          */
  297.         asid_t asid;
  298.        
  299.         asid = asid_get();
  300.         spinlock_lock(&new->lock);
  301.         new->asid = asid;
  302.         spinlock_unlock(&new->lock);
  303.     }
  304.     spinlock_unlock(&as_lock);
  305.     interrupts_restore(ipl);
  306.    
  307.     /*
  308.      * Perform architecture-specific steps.
  309.      * (e.g. write ASID to hardware register etc.)
  310.      */
  311.     as_install_arch(new);
  312.    
  313.     AS = new;
  314. }
  315.  
  316. /** Compute flags for virtual address translation subsytem.
  317.  *
  318.  * The address space area must be locked.
  319.  * Interrupts must be disabled.
  320.  *
  321.  * @param a Address space area.
  322.  *
  323.  * @return Flags to be used in page_mapping_insert().
  324.  */
  325. int get_area_flags(as_area_t *a)
  326. {
  327.     int flags;
  328.  
  329.     flags = PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
  330.    
  331.     if (a->flags & AS_AREA_READ)
  332.         flags |= PAGE_READ;
  333.        
  334.     if (a->flags & AS_AREA_WRITE)
  335.         flags |= PAGE_WRITE;
  336.    
  337.     if (a->flags & AS_AREA_EXEC)
  338.         flags |= PAGE_EXEC;
  339.    
  340.     return flags;
  341. }
  342.  
  343. /** Create page table.
  344.  *
  345.  * Depending on architecture, create either address space
  346.  * private or global page table.
  347.  *
  348.  * @param flags Flags saying whether the page table is for kernel address space.
  349.  *
  350.  * @return First entry of the page table.
  351.  */
  352. pte_t *page_table_create(int flags)
  353. {
  354.         ASSERT(as_operations);
  355.         ASSERT(as_operations->page_table_create);
  356.  
  357.         return as_operations->page_table_create(flags);
  358. }
  359.  
  360. /** Find address space area and change it.
  361.  *
  362.  * @param as Address space.
  363.  * @param address Virtual address belonging to the area to be changed. Must be page-aligned.
  364.  * @param size New size of the virtual memory block starting at address.
  365.  * @param flags Flags influencing the remap operation. Currently unused.
  366.  *
  367.  * @return address on success, (__address) -1 otherwise.
  368.  */
  369. __address as_remap(as_t *as, __address address, size_t size, int flags)
  370. {
  371.     as_area_t *area = NULL;
  372.     ipl_t ipl;
  373.     size_t pages;
  374.    
  375.     ipl = interrupts_disable();
  376.     spinlock_lock(&as->lock);
  377.    
  378.     /*
  379.      * Locate the area.
  380.      */
  381.     area = find_area_and_lock(as, address);
  382.     if (!area) {
  383.         spinlock_unlock(&as->lock);
  384.         return (__address) -1;
  385.     }
  386.  
  387.     pages = SIZE2FRAMES((address - area->base) + size);
  388.     if (pages < area->size) {
  389.         int i;
  390.  
  391.         /*
  392.          * Shrinking the area.
  393.          */
  394.         for (i = pages; i < area->size; i++) {
  395.             pte_t *pte;
  396.            
  397.             /*
  398.              * Releasing physical memory.
  399.              * This depends on the fact that the memory was allocated using frame_alloc().
  400.              */
  401.             pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
  402.             if (pte && PTE_VALID(pte)) {
  403.                 ASSERT(PTE_PRESENT(pte));
  404.                 frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));
  405.                 page_mapping_remove(as, area->base + i*PAGE_SIZE);
  406.             }
  407.         }
  408.         /*
  409.          * Invalidate TLB's.
  410.          */
  411.         tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
  412.         tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
  413.         tlb_shootdown_finalize();
  414.     }
  415.  
  416.     area->size = pages;
  417.    
  418.     spinlock_unlock(&area->lock);
  419.     spinlock_unlock(&as->lock);
  420.     interrupts_restore(ipl);
  421.  
  422.     return address;
  423. }
  424.  
  425. /** Find address space area and lock it.
  426.  *
  427.  * The address space must be locked and interrupts must be disabled.
  428.  *
  429.  * @param as Address space.
  430.  * @param va Virtual address.
  431.  *
  432.  * @return Locked address space area containing va on success or NULL on failure.
  433.  */
  434. as_area_t *find_area_and_lock(as_t *as, __address va)
  435. {
  436.     link_t *cur;
  437.     as_area_t *a;
  438.    
  439.     for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
  440.         a = list_get_instance(cur, as_area_t, link);
  441.         spinlock_lock(&a->lock);
  442.  
  443.         if ((va >= a->base) && (va < a->base + a->size * PAGE_SIZE))
  444.              return a;
  445.        
  446.         spinlock_unlock(&a->lock);
  447.     }
  448.  
  449.     return NULL;
  450. }
  451.