i386/ucla/src/lab4/inc/memlayout.h

   1 #ifndef JOS_INC_MEMLAYOUT_H
   2 #define JOS_INC_MEMLAYOUT_H
   3
   4 #ifndef __ASSEMBLER__
   5 #include <inc/types.h>
   6 #include <inc/queue.h>
   7 #include <inc/mmu.h>
   8 #endif /* not __ASSEMBLER__ */
   9
  10 /*
  11  * This file contains definitions for memory management in our OS,
  12  * which are relevant to both the kernel and user-mode software.
  13  */
  14
  15 // Global descriptor numbers
  16 #define GD_KT     0x08     // kernel text
  17 #define GD_KD     0x10     // kernel data
  18 #define GD_UT     0x18     // user text
  19 #define GD_UD     0x20     // user data
  20 #define GD_TSS    0x28     // Task segment selector
  21
  22 /*
  23  * Virtual memory map:                                Permissions
  24  *                                                    kernel/user
  25  *
  26  *    4 Gig -------->  +------------------------------+
  27  *                     |                              | RW/--
  28  *                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29  *                     :              .               :
  30  *                     :              .               :
  31  *                     :              .               :
  32  *                     |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| RW/--
  33  *                     |                              | RW/--
  34  *                     |   Remapped Physical Memory   | RW/--
  35  *                     |                              | RW/--
  36  *    KERNBASE, ---->  +------------------------------+ 0xf0000000      --+
  37  *    KSTACKTOP        |         Kernel Stack         | RW/--  KSTKSIZE   |
  38  *                     | - - - - - - - - - - - - - - -|                 PTSIZE
  39  *                     |      Invalid Memory (*)      | --/--             |
  40  *    ULIM     ------> +------------------------------+ 0xefc00000      --+
  41  *                     |  Cur. Page Table (User R-)   | R-/R-  PTSIZE
  42  *    UVPT      ---->  +------------------------------+ 0xef800000
  43  *                     |          RO PAGES            | R-/R-  PTSIZE
  44  *    UPAGES    ---->  +------------------------------+ 0xef400000
  45  *                     |           RO ENVS            | R-/R-  PTSIZE
  46  * UTOP,UENVS ------>  +------------------------------+ 0xef000000
  47  * UXSTACKTOP -/       |     User Exception Stack     | RW/RW  PGSIZE
  48  *                     +------------------------------+ 0xeefff000
  49  *                     |       Empty Memory (*)       | --/--  PGSIZE
  50  *    USTACKTOP  --->  +------------------------------+ 0xeeffe000
  51  *                     |      Normal User Stack       | RW/RW  PGSIZE
  52  *                     +------------------------------+ 0xeeffd000
  53  *                     |                              |
  54  *                     |                              |
  55  *                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  56  *                     .                              .
  57  *                     .                              .
  58  *                     .                              .
  59  *                     |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
  60  *                     |     Program Data & Heap      |
  61  *    UTEXT -------->  +------------------------------+ 0x00800000
  62  *    PFTEMP ------->  |       Empty Memory (*)       |        PTSIZE
  63  *                     |                              |
  64  *    UTEMP -------->  +------------------------------+ 0x00400000      --+
  65  *                     |       Empty Memory (*)       |                   |
  66  *                     | - - - - - - - - - - - - - - -|                   |
  67  *                     |  User STAB Data (optional)   |                 PTSIZE
  68  *    USTABDATA ---->  +------------------------------+ 0x00200000        |
  69  *                     |       Empty Memory (*)       |                   |
  70  *    0 ------------>  +------------------------------+                 --+
  71  *
  72  * (*) Note: The kernel ensures that "Invalid Memory" (ULIM) is *never*
  73  *     mapped.  "Empty Memory" is normally unmapped, but user programs may
  74  *     map pages there if desired.  JOS user programs map pages temporarily
  75  *     at UTEMP.
  76  */
  77
  78
  79 // All physical memory mapped at this address
  80 #define KERNBASE        0xF0000000
  81
  82 // At IOPHYSMEM (640K) there is a 384K hole for I/O.  From the kernel,
  83 // IOPHYSMEM can be addressed at KERNBASE + IOPHYSMEM.  The hole ends
  84 // at physical address EXTPHYSMEM.
  85 #define IOPHYSMEM       0x0A0000
  86 #define EXTPHYSMEM      0x100000
  87
  88 // Kernel stack.
  89 #define KSTACKTOP       KERNBASE
  90 #define KSTKSIZE        (8*PGSIZE)              // size of a kernel stack
  91 #define ULIM            (KSTACKTOP - PTSIZE)
  92
  93 /*
  94  * User read-only mappings! Anything below here til UTOP are readonly to user.
  95  * They are global pages mapped in at env allocation time.
  96  */
  97
  98 // User read-only virtual page table.
  99 // Entry PDX[UVPT] in the PD contains a pointer to the page directory itself,
 100 // thereby turning the PD into a page table, which maps all the PTEs
 101 // containing the page mappings for the entire virtual address space into that
 102 // 4 Meg region starting at UVPT.
 103 #define UVPT            (ULIM - PTSIZE)
 104 // Read-only copies of the Page structures
 105 #define UPAGES          (UVPT - PTSIZE)
 106 // Read-only copies of the global env structures
 107 #define UENVS           (UPAGES - PTSIZE)
 108
 109 /*
 110  * Top of user VM. User can manipulate VA from UTOP-1 and down!
 111  */
 112
 113 // Top of user-accessible VM
 114 #define UTOP            UENVS
 115 // Top of one-page user exception stack
 116 #define UXSTACKTOP      UTOP
 117 // Next page left invalid to guard against exception stack overflow; then:
 118 // Top of normal user stack
 119 #define USTACKTOP       (UTOP - 2*PGSIZE)
 120
 121 // Where user programs generally begin
 122 #define UTEXT           (2*PTSIZE)
 123
 124 // Used for temporary page mappings.  Typed 'void*' for convenience
 125 #define UTEMP           ((void*) PTSIZE)
 126 // Used for temporary page mappings for the user page-fault handler
 127 // (should not conflict with other temporary page mappings)
 128 #define PFTEMP          ((void*) ((uintptr_t) UTEMP + PTSIZE - PGSIZE))
 129 // The location of the user-level STABS data structure
 130 #define USTABDATA       (PTSIZE / 2)
 131
 132
 133 #ifndef __ASSEMBLER__
 134
 135 typedef uint32_t pte_t;
 136 typedef uint32_t pde_t;
 137
 138 #if JOS_USER
 139 /*
 140  * The page directory entry corresponding to the virtual address range
 141  * [VPT, VPT + PTSIZE) points to the page directory itself.  Thus, the page
 142  * directory is treated as a page table as well as a page directory.
 143  *
 144  * One result of treating the page directory as a page table is that all PTEs
 145  * can be accessed through a "virtual page table" at virtual address VPT (to
 146  * which vpt is set in entry.S).  The PTE for page number N is stored in
 147  * vpt[N].  (It's worth drawing a diagram of this!)
 148  *
 149  * A second consequence is that the contents of the current page directory
 150  * will always be available at virtual address (VPT + (VPT >> PGSHIFT)), to
 151  * which vpd is set in entry.S.
 152  */
 153 extern volatile pte_t vpt[];     // VA of "virtual page table"
 154 extern volatile pde_t vpd[];     // VA of current page directory
 155 #endif
 156
 157 #endif /* !__ASSEMBLER__ */
 158 #endif /* !JOS_INC_MEMLAYOUT_H */