root/include/asm-i386/pgtable.h

/* */

INCLUDED FROM

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. pte_read
19. pte_write
20. pte_exec
21. pte_dirty
22. pte_young
23. pte_cow
24. pte_wrprotect
25. pte_rdprotect
26. pte_exprotect
27. pte_mkclean
28. pte_mkold
29. pte_uncow
30. pte_mkwrite
31. pte_mkread
32. pte_mkexec
33. pte_mkdirty
34. pte_mkyoung
35. pte_mkcow
36. mk_pte
37. pte_modify
38. pte_page
39. pmd_page
40. pgd_offset
41. pmd_offset
42. pte_offset
43. pte_free_kernel
44. pte_alloc_kernel
45. pmd_free_kernel
46. pmd_alloc_kernel
47. pte_free
48. pte_alloc
49. pmd_free
50. pmd_alloc
51. pgd_free
52. pgd_alloc
53. 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); }
     /*  */
 133 extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_PRESENT; }
     /*  */
 134 extern inline int pte_inuse(pte_t *ptep)        { return mem_map[MAP_NR(ptep)] != 1; }
     /*  */
 135 extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
     /*  */
 136 extern inline void pte_reuse(pte_t * ptep)
     /*  */
 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); }
     /*  */
 143 extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~PAGE_MASK) != _PAGE_TABLE || pmd_val(pmd) > high_memory; }
     /*  */
 144 extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_PRESENT; }
     /*  */
 145 extern inline int pmd_inuse(pmd_t *pmdp)        { return 0; }
     /*  */
 146 extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
     /*  */
 147 extern inline void pmd_reuse(pmd_t * pmdp)      { }
     /*  */
 148 
 149 /*
 150  * The "pgd_xxx()" functions here are trivial for a folded two-level
 151  * setup: the pgd is never bad, and a pmd always exists (as it's folded
 152  * into the pgd entry)
 153  */
 154 extern inline int pgd_none(pgd_t pgd)           { return 0; }
     /*  */
 155 extern inline int pgd_bad(pgd_t pgd)            { return 0; }
     /*  */
 156 extern inline int pgd_present(pgd_t pgd)        { return 1; }
     /*  */
 157 extern inline int pgd_inuse(pgd_t * pgdp)       { return mem_map[MAP_NR(pgdp)] != 1; }
     /*  */
 158 extern inline void pgd_clear(pgd_t * pgdp)      { }
     /*  */
 159 extern inline void pgd_reuse(pgd_t * pgdp)
     /*  */
 160 {
 161         if (!(mem_map[MAP_NR(pgdp)] & MAP_PAGE_RESERVED))
 162                 mem_map[MAP_NR(pgdp)]++;
 163 }
 164 
 165 /*
 166  * The following only work if pte_present() is true.
 167  * Undefined behaviour if not..
 168  */
 169 extern inline int pte_read(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }
     /*  */
 170 extern inline int pte_write(pte_t pte)          { return pte_val(pte) & _PAGE_RW; }
     /*  */
 171 extern inline int pte_exec(pte_t pte)           { return pte_val(pte) & _PAGE_USER; }
     /*  */
 172 extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
     /*  */
 173 extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
     /*  */
 174 extern inline int pte_cow(pte_t pte)            { return pte_val(pte) & _PAGE_COW; }
     /*  */
 175 
 176 extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_RW; return pte; }
     /*  */
 177 extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }
     /*  */
 178 extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) &= ~_PAGE_USER; return pte; }
     /*  */
 179 extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
     /*  */
 180 extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
     /*  */
 181 extern inline pte_t pte_uncow(pte_t pte)        { pte_val(pte) &= ~_PAGE_COW; return pte; }
     /*  */
 182 extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) |= _PAGE_RW; return pte; }
     /*  */
 183 extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }
     /*  */
 184 extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) |= _PAGE_USER; return pte; }
     /*  */
 185 extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= _PAGE_DIRTY; return pte; }
     /*  */
 186 extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
     /*  */
 187 extern inline pte_t pte_mkcow(pte_t pte)        { pte_val(pte) |= _PAGE_COW; return pte; }
     /*  */
 188 
 189 /*
 190  * Conversion functions: convert a page and protection to a page entry,
 191  * and a page entry and page directory to the page they refer to.
 192  */
 193 extern inline pte_t mk_pte(unsigned long page, pgprot_t pgprot)
     /*  */
 194 { pte_t pte; pte_val(pte) = page | pgprot_val(pgprot); return pte; }
 195 
 196 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
     /*  */
 197 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 198 
 199 extern inline unsigned long pte_page(pte_t pte)
     /*  */
 200 { return pte_val(pte) & PAGE_MASK; }
 201 
 202 extern inline unsigned long pmd_page(pmd_t pmd)
     /*  */
 203 { return pmd_val(pmd) & PAGE_MASK; }
 204 
 205 /* to find an entry in a page-table-directory */
 206 extern inline pgd_t * pgd_offset(struct task_struct * tsk, unsigned long address)
     /*  */
 207 {
 208         return (pgd_t *) tsk->tss.cr3 + (address >> PGDIR_SHIFT);
 209 }
 210 
 211 /* Find an entry in the second-level page table.. */
 212 extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
     /*  */
 213 {
 214         return (pmd_t *) dir;
 215 }
 216 
 217 /* Find an entry in the third-level page table.. */ 
 218 extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
     /*  */
 219 {
 220         return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));
 221 }
 222 
 223 /*
 224  * Allocate and free page tables. The xxx_kernel() versions are
 225  * used to allocate a kernel page table - this turns on ASN bits
 226  * if any, and marks the page tables reserved.
 227  */
 228 extern inline void pte_free_kernel(pte_t * pte)
     /*  */
 229 {
 230         mem_map[MAP_NR(pte)] = 1;
 231         free_page((unsigned long) pte);
 232 }
 233 
 234 extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
     /*  */
 235 {
 236         address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
 237         if (pmd_none(*pmd)) {
 238                 pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);
 239                 if (pmd_none(*pmd)) {
 240                         if (page) {
 241                                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;
 242                                 mem_map[MAP_NR(page)] = MAP_PAGE_RESERVED;
 243                                 return page + address;
 244                         }
 245                         pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 246                         return NULL;
 247                 }
 248                 free_page((unsigned long) page);
 249         }
 250         if (pmd_bad(*pmd)) {
 251                 printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
 252                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 253                 return NULL;
 254         }
 255         return (pte_t *) pmd_page(*pmd) + address;
 256 }
 257 
 258 /*
 259  * allocating and freeing a pmd is trivial: the 1-entry pmd is
 260  * inside the pgd, so has no extra memory associated with it.
 261  */
 262 extern inline void pmd_free_kernel(pmd_t * pmd)
     /*  */
 263 {
 264 }
 265 
 266 extern inline pmd_t * pmd_alloc_kernel(pgd_t * pgd, unsigned long address)
     /*  */
 267 {
 268         return (pmd_t *) pgd;
 269 }
 270 
 271 extern inline void pte_free(pte_t * pte)
     /*  */
 272 {
 273         free_page((unsigned long) pte);
 274 }
 275 
 276 extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)
     /*  */
 277 {
 278         address = (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
 279         if (pmd_none(*pmd)) {
 280                 pte_t * page = (pte_t *) get_free_page(GFP_KERNEL);
 281                 if (pmd_none(*pmd)) {
 282                         if (page) {
 283                                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) page;
 284                                 return page + address;
 285                         }
 286                         pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 287                         return NULL;
 288                 }
 289                 free_page((unsigned long) page);
 290         }
 291         if (pmd_bad(*pmd)) {
 292                 printk("Bad pmd in pte_alloc: %08lx\n", pmd_val(*pmd));
 293                 pmd_val(*pmd) = _PAGE_TABLE | (unsigned long) BAD_PAGETABLE;
 294                 return NULL;
 295         }
 296         return (pte_t *) pmd_page(*pmd) + address;
 297 }
 298 
 299 /*
 300  * allocating and freeing a pmd is trivial: the 1-entry pmd is
 301  * inside the pgd, so has no extra memory associated with it.
 302  */
 303 extern inline void pmd_free(pmd_t * pmd)
     /*  */
 304 {
 305 }
 306 
 307 extern inline pmd_t * pmd_alloc(pgd_t * pgd, unsigned long address)
     /*  */
 308 {
 309         return (pmd_t *) pgd;
 310 }
 311 
 312 extern inline void pgd_free(pgd_t * pgd)
     /*  */
 313 {
 314         free_page((unsigned long) pgd);
 315 }
 316 
 317 extern inline pgd_t * pgd_alloc(void)
     /*  */
 318 {
 319         return (pgd_t *) get_free_page(GFP_KERNEL);
 320 }
 321 
 322 extern pgd_t swapper_pg_dir[1024];
 323 
 324 /*
 325  * The i386 doesn't have any external MMU info: the kernel page
 326  * tables contain all the necessary information.
 327  */
 328 extern inline void update_mmu_cache(struct vm_area_struct * vma,
     /*  */
 329         unsigned long address, pte_t pte)
 330 {
 331 }
 332 
 333 #endif /* _I386_PAGE_H */

/* */