include/asm-x86/pgtable.h

   1 #ifndef _ASM_X86_PGTABLE_H
   2 #define _ASM_X86_PGTABLE_H
   3
   4 #define FIRST_USER_ADDRESS      0
   5
   6 #define _PAGE_BIT_PRESENT       0       /* is present */
   7 #define _PAGE_BIT_RW            1       /* writeable */
   8 #define _PAGE_BIT_USER          2       /* userspace addressable */
   9 #define _PAGE_BIT_PWT           3       /* page write through */
  10 #define _PAGE_BIT_PCD           4       /* page cache disabled */
  11 #define _PAGE_BIT_ACCESSED      5       /* was accessed (raised by CPU) */
  12 #define _PAGE_BIT_DIRTY         6       /* was written to (raised by CPU) */
  13 #define _PAGE_BIT_FILE          6
  14 #define _PAGE_BIT_PSE           7       /* 4 MB (or 2MB) page */
  15 #define _PAGE_BIT_PAT           7       /* on 4KB pages */
  16 #define _PAGE_BIT_GLOBAL        8       /* Global TLB entry PPro+ */
  17 #define _PAGE_BIT_UNUSED1       9       /* available for programmer */
  18 #define _PAGE_BIT_UNUSED2       10
  19 #define _PAGE_BIT_UNUSED3       11
  20 #define _PAGE_BIT_PAT_LARGE     12      /* On 2MB or 1GB pages */
  21 #define _PAGE_BIT_NX           63       /* No execute: only valid after cpuid check */
  22
  23 #define _PAGE_PRESENT   (_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
  24 #define _PAGE_RW        (_AT(pteval_t, 1) << _PAGE_BIT_RW)
  25 #define _PAGE_USER      (_AT(pteval_t, 1) << _PAGE_BIT_USER)
  26 #define _PAGE_PWT       (_AT(pteval_t, 1) << _PAGE_BIT_PWT)
  27 #define _PAGE_PCD       (_AT(pteval_t, 1) << _PAGE_BIT_PCD)
  28 #define _PAGE_ACCESSED  (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
  29 #define _PAGE_DIRTY     (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
  30 #define _PAGE_PSE       (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
  31 #define _PAGE_GLOBAL    (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
  32 #define _PAGE_UNUSED1   (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)
  33 #define _PAGE_UNUSED2   (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED2)
  34 #define _PAGE_UNUSED3   (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
  35 #define _PAGE_PAT       (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
  36 #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
  37
  38 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
  39 #define _PAGE_NX        (_AT(pteval_t, 1) << _PAGE_BIT_NX)
  40 #else
  41 #define _PAGE_NX        (_AT(pteval_t, 0))
  42 #endif
  43
  44 /* If _PAGE_PRESENT is clear, we use these: */
  45 #define _PAGE_FILE      _PAGE_DIRTY     /* nonlinear file mapping,
  46                                          * saved PTE; unset:swap */
  47 #define _PAGE_PROTNONE  _PAGE_PSE       /* if the user mapped it with PROT_NONE;
  48                                            pte_present gives true */
  49
  50 #define _PAGE_TABLE     (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |        \
  51                          _PAGE_ACCESSED | _PAGE_DIRTY)
  52 #define _KERNPG_TABLE   (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED |    \
  53                          _PAGE_DIRTY)
  54
  55 /* Set of bits not changed in pte_modify */
  56 #define _PAGE_CHG_MASK  (PTE_MASK | _PAGE_PCD | _PAGE_PWT |             \
  57                          _PAGE_ACCESSED | _PAGE_DIRTY)
  58
  59 #define _PAGE_CACHE_MASK        (_PAGE_PCD | _PAGE_PWT)
  60 #define _PAGE_CACHE_WB          (0)
  61 #define _PAGE_CACHE_WC          (_PAGE_PWT)
  62 #define _PAGE_CACHE_UC_MINUS    (_PAGE_PCD)
  63 #define _PAGE_CACHE_UC          (_PAGE_PCD | _PAGE_PWT)
  64
  65 #define PAGE_NONE       __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
  66 #define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
  67                                  _PAGE_ACCESSED | _PAGE_NX)
  68
  69 #define PAGE_SHARED_EXEC        __pgprot(_PAGE_PRESENT | _PAGE_RW |     \
  70                                          _PAGE_USER | _PAGE_ACCESSED)
  71 #define PAGE_COPY_NOEXEC        __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
  72                                          _PAGE_ACCESSED | _PAGE_NX)
  73 #define PAGE_COPY_EXEC          __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
  74                                          _PAGE_ACCESSED)
  75 #define PAGE_COPY               PAGE_COPY_NOEXEC
  76 #define PAGE_READONLY           __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
  77                                          _PAGE_ACCESSED | _PAGE_NX)
  78 #define PAGE_READONLY_EXEC      __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
  79                                          _PAGE_ACCESSED)
  80
  81 #ifdef CONFIG_X86_32
  82 #define _PAGE_KERNEL_EXEC \
  83         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
  84 #define _PAGE_KERNEL (_PAGE_KERNEL_EXEC | _PAGE_NX)
  85
  86 #ifndef __ASSEMBLY__
  87 extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
  88 #endif  /* __ASSEMBLY__ */
  89 #else
  90 #define __PAGE_KERNEL_EXEC                                              \
  91         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
  92 #define __PAGE_KERNEL           (__PAGE_KERNEL_EXEC | _PAGE_NX)
  93 #endif
  94
  95 #define __PAGE_KERNEL_RO                (__PAGE_KERNEL & ~_PAGE_RW)
  96 #define __PAGE_KERNEL_RX                (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
  97 #define __PAGE_KERNEL_EXEC_NOCACHE      (__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT)
  98 #define __PAGE_KERNEL_WC                (__PAGE_KERNEL | _PAGE_CACHE_WC)
  99 #define __PAGE_KERNEL_NOCACHE           (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT)
 100 #define __PAGE_KERNEL_UC_MINUS          (__PAGE_KERNEL | _PAGE_PCD)
 101 #define __PAGE_KERNEL_VSYSCALL          (__PAGE_KERNEL_RX | _PAGE_USER)
 102 #define __PAGE_KERNEL_VSYSCALL_NOCACHE  (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
 103 #define __PAGE_KERNEL_LARGE             (__PAGE_KERNEL | _PAGE_PSE)
 104 #define __PAGE_KERNEL_LARGE_EXEC        (__PAGE_KERNEL_EXEC | _PAGE_PSE)
 105
 106 #define PAGE_KERNEL                     __pgprot(__PAGE_KERNEL)
 107 #define PAGE_KERNEL_RO                  __pgprot(__PAGE_KERNEL_RO)
 108 #define PAGE_KERNEL_EXEC                __pgprot(__PAGE_KERNEL_EXEC)
 109 #define PAGE_KERNEL_RX                  __pgprot(__PAGE_KERNEL_RX)
 110 #define PAGE_KERNEL_WC                  __pgprot(__PAGE_KERNEL_WC)
 111 #define PAGE_KERNEL_NOCACHE             __pgprot(__PAGE_KERNEL_NOCACHE)
 112 #define PAGE_KERNEL_UC_MINUS            __pgprot(__PAGE_KERNEL_UC_MINUS)
 113 #define PAGE_KERNEL_EXEC_NOCACHE        __pgprot(__PAGE_KERNEL_EXEC_NOCACHE)
 114 #define PAGE_KERNEL_LARGE               __pgprot(__PAGE_KERNEL_LARGE)
 115 #define PAGE_KERNEL_LARGE_EXEC          __pgprot(__PAGE_KERNEL_LARGE_EXEC)
 116 #define PAGE_KERNEL_VSYSCALL            __pgprot(__PAGE_KERNEL_VSYSCALL)
 117 #define PAGE_KERNEL_VSYSCALL_NOCACHE    __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)
 118
 119 /*         xwr */
 120 #define __P000  PAGE_NONE
 121 #define __P001  PAGE_READONLY
 122 #define __P010  PAGE_COPY
 123 #define __P011  PAGE_COPY
 124 #define __P100  PAGE_READONLY_EXEC
 125 #define __P101  PAGE_READONLY_EXEC
 126 #define __P110  PAGE_COPY_EXEC
 127 #define __P111  PAGE_COPY_EXEC
 128
 129 #define __S000  PAGE_NONE
 130 #define __S001  PAGE_READONLY
 131 #define __S010  PAGE_SHARED
 132 #define __S011  PAGE_SHARED
 133 #define __S100  PAGE_READONLY_EXEC
 134 #define __S101  PAGE_READONLY_EXEC
 135 #define __S110  PAGE_SHARED_EXEC
 136 #define __S111  PAGE_SHARED_EXEC
 137
 138 #ifndef __ASSEMBLY__
 139
 140 /*
 141  * ZERO_PAGE is a global shared page that is always zero: used
 142  * for zero-mapped memory areas etc..
 143  */
 144 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 145 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 146
 147 extern spinlock_t pgd_lock;
 148 extern struct list_head pgd_list;
 149
 150 /*
 151  * The following only work if pte_present() is true.
 152  * Undefined behaviour if not..
 153  */
 154 static inline int pte_dirty(pte_t pte)
 155 {
 156         return pte_flags(pte) & _PAGE_DIRTY;
 157 }
 158
 159 static inline int pte_young(pte_t pte)
 160 {
 161         return pte_flags(pte) & _PAGE_ACCESSED;
 162 }
 163
 164 static inline int pte_write(pte_t pte)
 165 {
 166         return pte_flags(pte) & _PAGE_RW;
 167 }
 168
 169 static inline int pte_file(pte_t pte)
 170 {
 171         return pte_flags(pte) & _PAGE_FILE;
 172 }
 173
 174 static inline int pte_huge(pte_t pte)
 175 {
 176         return pte_flags(pte) & _PAGE_PSE;
 177 }
 178
 179 static inline int pte_global(pte_t pte)
 180 {
 181         return pte_flags(pte) & _PAGE_GLOBAL;
 182 }
 183
 184 static inline int pte_exec(pte_t pte)
 185 {
 186         return !(pte_flags(pte) & _PAGE_NX);
 187 }
 188
 189 static inline int pte_special(pte_t pte)
 190 {
 191         return 0;
 192 }
 193
 194 static inline int pmd_large(pmd_t pte)
 195 {
 196         return (pmd_val(pte) & (_PAGE_PSE | _PAGE_PRESENT)) ==
 197                 (_PAGE_PSE | _PAGE_PRESENT);
 198 }
 199
 200 static inline pte_t pte_mkclean(pte_t pte)
 201 {
 202         return __pte(pte_val(pte) & ~_PAGE_DIRTY);
 203 }
 204
 205 static inline pte_t pte_mkold(pte_t pte)
 206 {
 207         return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
 208 }
 209
 210 static inline pte_t pte_wrprotect(pte_t pte)
 211 {
 212         return __pte(pte_val(pte) & ~_PAGE_RW);
 213 }
 214
 215 static inline pte_t pte_mkexec(pte_t pte)
 216 {
 217         return __pte(pte_val(pte) & ~_PAGE_NX);
 218 }
 219
 220 static inline pte_t pte_mkdirty(pte_t pte)
 221 {
 222         return __pte(pte_val(pte) | _PAGE_DIRTY);
 223 }
 224
 225 static inline pte_t pte_mkyoung(pte_t pte)
 226 {
 227         return __pte(pte_val(pte) | _PAGE_ACCESSED);
 228 }
 229
 230 static inline pte_t pte_mkwrite(pte_t pte)
 231 {
 232         return __pte(pte_val(pte) | _PAGE_RW);
 233 }
 234
 235 static inline pte_t pte_mkhuge(pte_t pte)
 236 {
 237         return __pte(pte_val(pte) | _PAGE_PSE);
 238 }
 239
 240 static inline pte_t pte_clrhuge(pte_t pte)
 241 {
 242         return __pte(pte_val(pte) & ~_PAGE_PSE);
 243 }
 244
 245 static inline pte_t pte_mkglobal(pte_t pte)
 246 {
 247         return __pte(pte_val(pte) | _PAGE_GLOBAL);
 248 }
 249
 250 static inline pte_t pte_clrglobal(pte_t pte)
 251 {
 252         return __pte(pte_val(pte) & ~_PAGE_GLOBAL);
 253 }
 254
 255 static inline pte_t pte_mkspecial(pte_t pte)
 256 {
 257         return pte;
 258 }
 259
 260 extern pteval_t __supported_pte_mask;
 261
 262 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 263 {
 264         return __pte((((phys_addr_t)page_nr << PAGE_SHIFT) |
 265                       pgprot_val(pgprot)) & __supported_pte_mask);
 266 }
 267
 268 static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 269 {
 270         return __pmd((((phys_addr_t)page_nr << PAGE_SHIFT) |
 271                       pgprot_val(pgprot)) & __supported_pte_mask);
 272 }
 273
 274 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 275 {
 276         pteval_t val = pte_val(pte);
 277
 278         /*
 279          * Chop off the NX bit (if present), and add the NX portion of
 280          * the newprot (if present):
 281          */
 282         val &= _PAGE_CHG_MASK;
 283         val |= pgprot_val(newprot) & (~_PAGE_CHG_MASK) & __supported_pte_mask;
 284
 285         return __pte(val);
 286 }
 287
 288 /* mprotect needs to preserve PAT bits when updating vm_page_prot */
 289 #define pgprot_modify pgprot_modify
 290 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 291 {
 292         pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK;
 293         pgprotval_t addbits = pgprot_val(newprot);
 294         return __pgprot(preservebits | addbits);
 295 }
 296
 297 #define pte_pgprot(x) __pgprot(pte_flags(x) & ~PTE_MASK)
 298
 299 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
 300
 301 #ifndef __ASSEMBLY__
 302 #define __HAVE_PHYS_MEM_ACCESS_PROT
 303 struct file;
 304 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 305                               unsigned long size, pgprot_t vma_prot);
 306 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 307                               unsigned long size, pgprot_t *vma_prot);
 308 #endif
 309
 310 /* Install a pte for a particular vaddr in kernel space. */
 311 void set_pte_vaddr(unsigned long vaddr, pte_t pte);
 312
 313 #ifdef CONFIG_PARAVIRT
 314 #include <asm/paravirt.h>
 315 #else  /* !CONFIG_PARAVIRT */
 316 #define set_pte(ptep, pte)              native_set_pte(ptep, pte)
 317 #define set_pte_at(mm, addr, ptep, pte) native_set_pte_at(mm, addr, ptep, pte)
 318
 319 #define set_pte_present(mm, addr, ptep, pte)                            \
 320         native_set_pte_present(mm, addr, ptep, pte)
 321 #define set_pte_atomic(ptep, pte)                                       \
 322         native_set_pte_atomic(ptep, pte)
 323
 324 #define set_pmd(pmdp, pmd)              native_set_pmd(pmdp, pmd)
 325
 326 #ifndef __PAGETABLE_PUD_FOLDED
 327 #define set_pgd(pgdp, pgd)              native_set_pgd(pgdp, pgd)
 328 #define pgd_clear(pgd)                  native_pgd_clear(pgd)
 329 #endif
 330
 331 #ifndef set_pud
 332 # define set_pud(pudp, pud)             native_set_pud(pudp, pud)
 333 #endif
 334
 335 #ifndef __PAGETABLE_PMD_FOLDED
 336 #define pud_clear(pud)                  native_pud_clear(pud)
 337 #endif
 338
 339 #define pte_clear(mm, addr, ptep)       native_pte_clear(mm, addr, ptep)
 340 #define pmd_clear(pmd)                  native_pmd_clear(pmd)
 341
 342 #define pte_update(mm, addr, ptep)              do { } while (0)
 343 #define pte_update_defer(mm, addr, ptep)        do { } while (0)
 344 #endif  /* CONFIG_PARAVIRT */
 345
 346 #endif  /* __ASSEMBLY__ */
 347
 348 #ifdef CONFIG_X86_32
 349 # include "pgtable_32.h"
 350 #else
 351 # include "pgtable_64.h"
 352 #endif
 353
 354 /*
 355  * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
 356  *
 357  * this macro returns the index of the entry in the pgd page which would
 358  * control the given virtual address
 359  */
 360 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 361
 362 /*
 363  * pgd_offset() returns a (pgd_t *)
 364  * pgd_index() is used get the offset into the pgd page's array of pgd_t's;
 365  */
 366 #define pgd_offset(mm, address) ((mm)->pgd + pgd_index((address)))
 367 /*
 368  * a shortcut which implies the use of the kernel's pgd, instead
 369  * of a process's
 370  */
 371 #define pgd_offset_k(address) pgd_offset(&init_mm, (address))
 372
 373
 374 #define KERNEL_PGD_BOUNDARY     pgd_index(PAGE_OFFSET)
 375 #define KERNEL_PGD_PTRS         (PTRS_PER_PGD - KERNEL_PGD_BOUNDARY)
 376
 377 #ifndef __ASSEMBLY__
 378
 379 enum {
 380         PG_LEVEL_NONE,
 381         PG_LEVEL_4K,
 382         PG_LEVEL_2M,
 383         PG_LEVEL_1G,
 384         PG_LEVEL_NUM
 385 };
 386
 387 #ifdef CONFIG_PROC_FS
 388 extern void update_page_count(int level, unsigned long pages);
 389 #else
 390 static inline void update_page_count(int level, unsigned long pages) { }
 391 #endif
 392
 393 /*
 394  * Helper function that returns the kernel pagetable entry controlling
 395  * the virtual address 'address'. NULL means no pagetable entry present.
 396  * NOTE: the return type is pte_t but if the pmd is PSE then we return it
 397  * as a pte too.
 398  */
 399 extern pte_t *lookup_address(unsigned long address, unsigned int *level);
 400
 401 /* local pte updates need not use xchg for locking */
 402 static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
 403 {
 404         pte_t res = *ptep;
 405
 406         /* Pure native function needs no input for mm, addr */
 407         native_pte_clear(NULL, 0, ptep);
 408         return res;
 409 }
 410
 411 static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
 412                                      pte_t *ptep , pte_t pte)
 413 {
 414         native_set_pte(ptep, pte);
 415 }
 416
 417 #ifndef CONFIG_PARAVIRT
 418 /*
 419  * Rules for using pte_update - it must be called after any PTE update which
 420  * has not been done using the set_pte / clear_pte interfaces.  It is used by
 421  * shadow mode hypervisors to resynchronize the shadow page tables.  Kernel PTE
 422  * updates should either be sets, clears, or set_pte_atomic for P->P
 423  * transitions, which means this hook should only be called for user PTEs.
 424  * This hook implies a P->P protection or access change has taken place, which
 425  * requires a subsequent TLB flush.  The notification can optionally be delayed
 426  * until the TLB flush event by using the pte_update_defer form of the
 427  * interface, but care must be taken to assure that the flush happens while
 428  * still holding the same page table lock so that the shadow and primary pages
 429  * do not become out of sync on SMP.
 430  */
 431 #define pte_update(mm, addr, ptep)              do { } while (0)
 432 #define pte_update_defer(mm, addr, ptep)        do { } while (0)
 433 #endif
 434
 435 /*
 436  * We only update the dirty/accessed state if we set
 437  * the dirty bit by hand in the kernel, since the hardware
 438  * will do the accessed bit for us, and we don't want to
 439  * race with other CPU's that might be updating the dirty
 440  * bit at the same time.
 441  */
 442 struct vm_area_struct;
 443
 444 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 445 extern int ptep_set_access_flags(struct vm_area_struct *vma,
 446                                  unsigned long address, pte_t *ptep,
 447                                  pte_t entry, int dirty);
 448
 449 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 450 extern int ptep_test_and_clear_young(struct vm_area_struct *vma,
 451                                      unsigned long addr, pte_t *ptep);
 452
 453 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 454 extern int ptep_clear_flush_young(struct vm_area_struct *vma,
 455                                   unsigned long address, pte_t *ptep);
 456
 457 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 458 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 459                                        pte_t *ptep)
 460 {
 461         pte_t pte = native_ptep_get_and_clear(ptep);
 462         pte_update(mm, addr, ptep);
 463         return pte;
 464 }
 465
 466 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 467 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 468                                             unsigned long addr, pte_t *ptep,
 469                                             int full)
 470 {
 471         pte_t pte;
 472         if (full) {
 473                 /*
 474                  * Full address destruction in progress; paravirt does not
 475                  * care about updates and native needs no locking
 476                  */
 477                 pte = native_local_ptep_get_and_clear(ptep);
 478         } else {
 479                 pte = ptep_get_and_clear(mm, addr, ptep);
 480         }
 481         return pte;
 482 }
 483
 484 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 485 static inline void ptep_set_wrprotect(struct mm_struct *mm,
 486                                       unsigned long addr, pte_t *ptep)
 487 {
 488         clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
 489         pte_update(mm, addr, ptep);
 490 }
 491
 492 /*
 493  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
 494  *
 495  *  dst - pointer to pgd range anwhere on a pgd page
 496  *  src - ""
 497  *  count - the number of pgds to copy.
 498  *
 499  * dst and src can be on the same page, but the range must not overlap,
 500  * and must not cross a page boundary.
 501  */
 502 static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
 503 {
 504        memcpy(dst, src, count * sizeof(pgd_t));
 505 }
 506
 507
 508 #include <asm-generic/pgtable.h>
 509 #endif  /* __ASSEMBLY__ */
 510
 511 #endif  /* _ASM_X86_PGTABLE_H */