root/include/asm-i386/pgtable.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. pte_none
  2. pte_present
  3. pte_inuse
  4. pte_clear
  5. pte_reuse
  6. pmd_none
  7. pmd_bad
  8. pmd_present
  9. pmd_inuse
  10. pmd_clear
  11. pmd_reuse
  12. pgd_none
  13. pgd_bad
  14. pgd_present
  15. pgd_inuse
  16. pgd_clear
  17. pgd_reuse
  18. pgd_none
  19. pgd_bad
  20. pgd_present
  21. pgd_clear
  22. pte_read
  23. pte_write
  24. pte_exec
  25. pte_dirty
  26. pte_young
  27. pte_cow
  28. pte_wrprotect
  29. pte_rdprotect
  30. pte_exprotect
  31. pte_mkclean
  32. pte_mkold
  33. pte_uncow
  34. pte_mkwrite
  35. pte_mkread
  36. pte_mkexec
  37. pte_mkdirty
  38. pte_mkyoung
  39. pte_mkcow
  40. mk_pte
  41. pte_modify
  42. pte_page
  43. pmd_page
  44. pgd_page
  45. pgd_set
  46. pgd_offset
  47. pmd_offset
  48. pte_offset
  49. pte_free_kernel
  50. pte_alloc_kernel
  51. pmd_free_kernel
  52. pmd_alloc_kernel
  53. pte_free
  54. pte_alloc
  55. pmd_free
  56. pmd_alloc
  57. pgd_free
  58. pgd_alloc
  59. update_mmu_cache

   1 #ifndef _I386_PGTABLE_H
   2 #define _I386_PGTABLE_H
   3 
   4 /*
   5  * The Linux memory management assumes a three-level page table setup. On
   6  * the i386, we use that, but "fold" the mid level into the top-level page
   7  * table, so that we physically have the same two-level page table as the
   8  * i386 mmu expects.
   9  *
  10  * This file contains the functions and defines necessary to modify and use
  11  * the i386 page table tree.
  12  */
  13 
  14 /* PMD_SHIFT determines the size of the area a second-level page table can map */
  15 #define PMD_SHIFT       22
  16 #define PMD_SIZE        (1UL << PMD_SHIFT)
  17 #define PMD_MASK        (~(PMD_SIZE-1))
  18 
  19 /* PGDIR_SHIFT determines what a third-level page table entry can map */
  20 #define PGDIR_SHIFT     22
  21 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  22 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  23 
  24 /*
  25  * entries per page directory level: the i386 is two-level, so
  26  * we don't really have any PMD directory physically.
  27  */
  28 #define PTRS_PER_PTE    1024
  29 #define PTRS_PER_PMD    1
  30 #define PTRS_PER_PGD    1024
  31 
  32 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  33  * current 8MB value just means that there will be a 8MB "hole" after the
  34  * physical memory until the kernel virtual memory starts.  That means that
  35  * any out-of-bounds memory accesses will hopefully be caught.
  36  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
  37  * area for the same reason. ;)
  38  */
  39 #define VMALLOC_OFFSET  (8*1024*1024)
  40 #define VMALLOC_START ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
  41 #define VMALLOC_VMADDR(x) (TASK_SIZE + (unsigned long)(x))
  42 
  43 #define _PAGE_PRESENT   0x001
  44 #define _PAGE_RW        0x002
  45 #define _PAGE_USER      0x004
  46 #define _PAGE_PCD       0x010
  47 #define _PAGE_ACCESSED  0x020
  48 #define _PAGE_DIRTY     0x040
  49 #define _PAGE_COW       0x200   /* implemented in software (one of the AVL bits) */
  50 
  51 #define _PAGE_TABLE     (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
  52 #define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
  53 
  54 #define PAGE_NONE       __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
  55 #define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
  56 #define PAGE_COPY       __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_COW)
  57 #define PAGE_READONLY   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
  58 #define PAGE_KERNEL     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
  59 
  60 /*
  61  * The i386 can't do page protection for execute, and considers that the same are read.
  62  * Also, write permissions imply read permissions. This is the closest we can get..
  63  */
  64 #define __P000  PAGE_NONE
  65 #define __P001  PAGE_READONLY
  66 #define __P010  PAGE_COPY
  67 #define __P011  PAGE_COPY
  68 #define __P100  PAGE_READONLY
  69 #define __P101  PAGE_READONLY
  70 #define __P110  PAGE_COPY
  71 #define __P111  PAGE_COPY
  72 
  73 #define __S000  PAGE_NONE
  74 #define __S001  PAGE_READONLY
  75 #define __S010  PAGE_SHARED
  76 #define __S011  PAGE_SHARED
  77 #define __S100  PAGE_READONLY
  78 #define __S101  PAGE_READONLY
  79 #define __S110  PAGE_SHARED
  80 #define __S111  PAGE_SHARED
  81 
  82 /*
  83  * Define this if things work differently on a i386 and a i486:
  84  * it will (on a i486) warn about kernel memory accesses that are
  85  * done without a 'verify_area(VERIFY_WRITE,..)'
  86  */
  87 #undef CONFIG_TEST_VERIFY_AREA
  88 
  89 /* page table for 0-4MB for everybody */
  90 extern unsigned long pg0[1024];
  91 
  92 /*
  93  * BAD_PAGETABLE is used when we need a bogus page-table, while
  94  * BAD_PAGE is used for a bogus page.
  95  *
  96  * ZERO_PAGE is a global shared page that is always zero: used
  97  * for zero-mapped memory areas etc..
  98  */
  99 extern pte_t __bad_page(void);
 100 extern pte_t * __bad_pagetable(void);
 101 
 102 extern unsigned long __zero_page(void);
 103 
 104 #define BAD_PAGETABLE __bad_pagetable()
 105 #define BAD_PAGE __bad_page()
 106 #define ZERO_PAGE __zero_page()
 107 
 108 /* number of bits that fit into a memory pointer */
 109 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
 110 
 111 /* to align the pointer to a pointer address */
 112 #define PTR_MASK                        (~(sizeof(void*)-1))
 113 
 114 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 115 /* 64-bit machines, beware!  SRB. */
 116 #define SIZEOF_PTR_LOG2                 2
 117 
 118 /* to find an entry in a page-table */
 119 #define PAGE_PTR(address) \
 120 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 121 
 122 /* to set the page-dir */
 123 #define SET_PAGE_DIR(tsk,pgdir) \
 124 do { \
 125         (tsk)->tss.cr3 = (unsigned long) (pgdir); \
 126         if ((tsk) == current) \
 127                 __asm__ __volatile__("movl %0,%%cr3": :"a" ((tsk)->tss.cr3)); \
 128 } while (0)
 129 
 130 extern unsigned long high_memory;
 131 
 132 extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
     /* [previous][next][first][last][top][bottom][index][help] */
 133 extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_PRESENT; }
     /* [previous][next][first][last][top][bottom][index][help] */
 134 extern inline int pte_inuse(pte_t *ptep)        { return mem_map[MAP_NR(ptep)] != 1; }
     /* [previous][next][first][last][top][bottom][index][help] */
 135 extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 136 extern inline void pte_reuse(pte_t * ptep)
     /* [previous][next][first][last][top][bottom][index][help] */
 137 {
 138         if (!(mem_map[MAP_NR(ptep)] & MAP_PAGE_RESERVED))
 139                 mem_map[MAP_NR(ptep)]++;
 140 }
 141 
 142 extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
     /* [previous][next][first][last][top][bottom][index][help] */
 143 extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~PAGE_MASK) != _PAGE_TABLE || pmd_val(pmd) > high_memory; }
     /* [previous][next][first][last][top][bottom][index][help] */
 144 extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_PRESENT; }
     /* [previous][next][first][last][top][bottom][index][help] */
 145 extern inline int pmd_inuse(pmd_t *pmdp)        { return 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 146 extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 147 extern inline void pmd_reuse(pmd_t * pmdp)      { }
     /* [previous][next][first][last][top][bottom][index][help] */
 148 
 149 #ifdef THREE_LEVEL
 150 /*
 151  * The "pgd_xxx()" functions here are trivial for a folded two-level
 152  * setup: the pgd is never bad, and a pmd always exists (as it's folded
 153  * into the pgd entry)
 154  */
 155 extern inline int pgd_none(pgd_t pgd)           { return 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 156 extern inline int pgd_bad(pgd_t pgd)            { return 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 157 extern inline int pgd_present(pgd_t pgd)        { return 1; }
     /* [previous][next][first][last][top][bottom][index][help] */
 158 extern inline int pgd_inuse(pgd_t * pgdp)       { return mem_map[MAP_NR(pgdp)] != 1; }
     /* [previous][next][first][last][top][bottom][index][help] */
 159 extern inline void pgd_clear(pgd_t * pgdp)      { }
     /* [previous][next][first][last][top][bottom][index][help] */
 160 extern inline void pgd_reuse(pgd_t * pgdp)
     /* [previous][next][first][last][top][bottom][index][help] */
 161 {
 162         if (!(mem_map[MAP_NR(pgdp)] & MAP_PAGE_RESERVED))
 163                 mem_map[MAP_NR(pgdp)]++;
 164 }
 165 #else
 166 /*
 167  * These are the old (and incorrect) ones needed for code that doesn't
 168  * know about three-level yet..
 169  */
 170 extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
     /* [previous][next][first][last][top][bottom][index][help] */
 171 extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~PAGE_MASK) != _PAGE_TABLE || pgd_val(pgd) > high_memory; }
     /* [previous][next][first][last][top][bottom][index][help] */
 172 extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_PRESENT; }
     /* [previous][next][first][last][top][bottom][index][help] */
 173 extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
     /* [previous][next][first][last][top][bottom][index][help] */
 174 #endif
 175 
 176 /*
 177  * The following only work if pte_present() is true.
 178  * Undefined behaviour if not..
 179  */
 180 extern inline int pte_read(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }
     /* [previous][next][first][last][top][bottom][index][help] */
 181 extern inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_RW; }
     /* [previous][next][first][last][top][bottom][index][help] */
 182 extern inline int pte_exec(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }
     /* [previous][next][first][last][top][bottom][index][help] */
 183 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
     /* [previous][next][first][last][top][bottom][index][help] */
 184 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
     /* [previous][next][first][last][top][bottom][index][help] */
 185 extern inline int pte_cow(pte_t pte)            { return pte_val(pte) & _PAGE_COW; }
     /* [previous][next][first][last][top][bottom][index][help] */
 186 
 187 extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_RW; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 188 extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 189 extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 190 extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 191 extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 192 extern inline pte_t pte_uncow(pte_t pte)        { pte_val(pte) &= ~_PAGE_COW; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 193 extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) |= _PAGE_RW; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 194 extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 195 extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 196 extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= _PAGE_DIRTY; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 197 extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 198 extern inline pte_t pte_mkcow(pte_t pte)        { pte_val(pte) |= _PAGE_COW; return pte; }
     /* [previous][next][first][last][top][bottom][index][help] */
 199 
 200 /*
 201  * Conversion functions: convert a page and protection to a page entry,
 202  * and a page entry and page directory to the page they refer to.
 203  */
 204 extern inline pte_t mk_pte(unsigned long page, pgprot_t pgprot)
     /* [previous][next][first][last][top][bottom][index][help] */
 205 { pte_t pte; pte_val(pte) = page | pgprot_val(pgprot); return pte; }
 206 
 207 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
     /* [previous][next][first][last][top][bottom][index][help] */
 208 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 209 
 210 extern inline unsigned long pte_page(pte_t pte)
     /* [previous][next][first][last][top][bottom][index][help] */
 211 { return pte_val(pte) & PAGE_MASK; }
 212 
 213 extern inline unsigned long pmd_page(pmd_t pmd)
     /* [previous][next][first][last][top][bottom][index][help] */
 214 { return pmd_val(pmd) & PAGE_MASK; }
 215 
 216 #ifndef THREE_LEVEL
 217 
 218 extern inline unsigned long pgd_page(pgd_t pgd)
     /* [previous][next][first][last][top][bottom][index][help] */
 219 { return pgd_val(pgd) & PAGE_MASK; }
 220 
 221 extern inline void pgd_set(pgd_t * pgdp, pte_t * ptep)
     /* [previous][next][first][last][top][bottom][index][help] */
 222 { pgd_val(*pgdp) = _PAGE_TABLE | (unsigned long) ptep; }
 223 
 224 #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 225 
 226 /* the no. of pointers that fit on a page: this will go away */
 227 #define PTRS_PER_PAGE   (PAGE_SIZE/sizeof(void*))
 228 
 229 #endif
 230 
 231 /* to find an entry in a page-table-directory */
 232 extern inline pgd_t * pgd_offset(struct task_struct * tsk, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 233 {
 234         return (pgd_t *) tsk->tss.cr3 + (address >> PGDIR_SHIFT);
 235 }
 236 
 237 /* Find an entry in the second-level page table.. */
 238 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 239 {
 240         return (pmd_t *) dir;
 241 }
 242 
 243 /* Find an entry in the third-level page table.. */ 
 244 extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 245 {
 246         return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));
 247 }
 248 
 249 /*
 250  * Allocate and free page tables. The xxx_kernel() versions are
 251  * used to allocate a kernel page table - this turns on ASN bits
 252  * if any, and marks the page tables reserved.
 253  */
 254 extern inline void pte_free_kernel(pte_t * pte)
     /* [previous][next][first][last][top][bottom][index][help] */
 255 {
 256         mem_map[MAP_NR(pte)] = 1;
 257         free_page((unsigned long) pte);
 258 }
 259 
 260 extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 261 {
 262         address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
 263         if (pmd_none(*pmd)) {
 264                 pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);
 265                 if (pmd_none(*pmd)) {
 266                         if (page) {
 267                                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;
 268                                 mem_map[MAP_NR(page)] = MAP_PAGE_RESERVED;
 269                                 return page + address;
 270                         }
 271                         pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 272                         return NULL;
 273                 }
 274                 free_page((unsigned long) page);
 275         }
 276         if (pmd_bad(*pmd)) {
 277                 printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
 278                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 279                 return NULL;
 280         }
 281         return (pte_t *) pmd_page(*pmd) + address;
 282 }
 283 
 284 /*
 285  * allocating and freeing a pmd is trivial: the 1-entry pmd is
 286  * inside the pgd, so has no extra memory associated with it.
 287  */
 288 extern inline void pmd_free_kernel(pmd_t * pmd)
     /* [previous][next][first][last][top][bottom][index][help] */
 289 {
 290 }
 291 
 292 extern inline pmd_t * pmd_alloc_kernel(pgd_t * pgd, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 293 {
 294         return (pmd_t *) pgd;
 295 }
 296 
 297 extern inline void pte_free(pte_t * pte)
     /* [previous][next][first][last][top][bottom][index][help] */
 298 {
 299         free_page((unsigned long) pte);
 300 }
 301 
 302 extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 303 {
 304         address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
 305         if (pmd_none(*pmd)) {
 306                 pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);
 307                 if (pmd_none(*pmd)) {
 308                         if (page) {
 309                                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;
 310                                 return page + address;
 311                         }
 312                         pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 313                         return NULL;
 314                 }
 315                 free_page((unsigned long) page);
 316         }
 317         if (pmd_bad(*pmd)) {
 318                 printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
 319                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 320                 return NULL;
 321         }
 322         return (pte_t *) pmd_page(*pmd) + address;
 323 }
 324 
 325 /*
 326  * allocating and freeing a pmd is trivial: the 1-entry pmd is
 327  * inside the pgd, so has no extra memory associated with it.
 328  */
 329 extern inline void pmd_free(pmd_t * pmd)
     /* [previous][next][first][last][top][bottom][index][help] */
 330 {
 331 }
 332 
 333 extern inline pmd_t * pmd_alloc(pgd_t * pgd, unsigned long address)
     /* [previous][next][first][last][top][bottom][index][help] */
 334 {
 335         return (pmd_t *) pgd;
 336 }
 337 
 338 extern inline void pgd_free(pgd_t * pgd)
     /* [previous][next][first][last][top][bottom][index][help] */
 339 {
 340         free_page((unsigned long) pgd);
 341 }
 342 
 343 extern inline pgd_t * pgd_alloc(void)
     /* [previous][next][first][last][top][bottom][index][help] */
 344 {
 345         return (pgd_t *) get_free_page(GFP_KERNEL);
 346 }
 347 
 348 extern pgd_t swapper_pg_dir[1024];
 349 
 350 /*
 351  * The i386 doesn't have any external MMU info: the kernel page
 352  * tables contain all the necessary information.
 353  */
 354 extern inline void update_mmu_cache(struct vm_area_struct * vma,
     /* [previous][next][first][last][top][bottom][index][help] */
 355         unsigned long address, pte_t pte)
 356 {
 357 }
 358 
 359 #endif /* _I386_PAGE_H */

/* [previous][next][first][last][top][bottom][index][help] */