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_PFN_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 #define __PAGE_KERNEL_EXEC                                              \
  82         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
  83 #define __PAGE_KERNEL           (__PAGE_KERNEL_EXEC | _PAGE_NX)
  84
  85 #define __PAGE_KERNEL_RO                (__PAGE_KERNEL & ~_PAGE_RW)
  86 #define __PAGE_KERNEL_RX                (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
  87 #define __PAGE_KERNEL_EXEC_NOCACHE      (__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT)
  88 #define __PAGE_KERNEL_WC                (__PAGE_KERNEL | _PAGE_CACHE_WC)
  89 #define __PAGE_KERNEL_NOCACHE           (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT)
  90 #define __PAGE_KERNEL_UC_MINUS          (__PAGE_KERNEL | _PAGE_PCD)
  91 #define __PAGE_KERNEL_VSYSCALL          (__PAGE_KERNEL_RX | _PAGE_USER)
  92 #define __PAGE_KERNEL_VSYSCALL_NOCACHE  (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
  93 #define __PAGE_KERNEL_LARGE             (__PAGE_KERNEL | _PAGE_PSE)
  94 #define __PAGE_KERNEL_LARGE_NOCACHE     (__PAGE_KERNEL | _PAGE_CACHE_UC | _PAGE_PSE)
  95 #define __PAGE_KERNEL_LARGE_EXEC        (__PAGE_KERNEL_EXEC | _PAGE_PSE)
  96
  97 #define PAGE_KERNEL                     __pgprot(__PAGE_KERNEL)
  98 #define PAGE_KERNEL_RO                  __pgprot(__PAGE_KERNEL_RO)
  99 #define PAGE_KERNEL_EXEC                __pgprot(__PAGE_KERNEL_EXEC)
 100 #define PAGE_KERNEL_RX                  __pgprot(__PAGE_KERNEL_RX)
 101 #define PAGE_KERNEL_WC                  __pgprot(__PAGE_KERNEL_WC)
 102 #define PAGE_KERNEL_NOCACHE             __pgprot(__PAGE_KERNEL_NOCACHE)
 103 #define PAGE_KERNEL_UC_MINUS            __pgprot(__PAGE_KERNEL_UC_MINUS)
 104 #define PAGE_KERNEL_EXEC_NOCACHE        __pgprot(__PAGE_KERNEL_EXEC_NOCACHE)
 105 #define PAGE_KERNEL_LARGE               __pgprot(__PAGE_KERNEL_LARGE)
 106 #define PAGE_KERNEL_LARGE_NOCACHE       __pgprot(__PAGE_KERNEL_LARGE_NOCACHE)
 107 #define PAGE_KERNEL_LARGE_EXEC          __pgprot(__PAGE_KERNEL_LARGE_EXEC)
 108 #define PAGE_KERNEL_VSYSCALL            __pgprot(__PAGE_KERNEL_VSYSCALL)
 109 #define PAGE_KERNEL_VSYSCALL_NOCACHE    __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)
 110
 111 /*         xwr */
 112 #define __P000  PAGE_NONE
 113 #define __P001  PAGE_READONLY
 114 #define __P010  PAGE_COPY
 115 #define __P011  PAGE_COPY
 116 #define __P100  PAGE_READONLY_EXEC
 117 #define __P101  PAGE_READONLY_EXEC
 118 #define __P110  PAGE_COPY_EXEC
 119 #define __P111  PAGE_COPY_EXEC
 120
 121 #define __S000  PAGE_NONE
 122 #define __S001  PAGE_READONLY
 123 #define __S010  PAGE_SHARED
 124 #define __S011  PAGE_SHARED
 125 #define __S100  PAGE_READONLY_EXEC
 126 #define __S101  PAGE_READONLY_EXEC
 127 #define __S110  PAGE_SHARED_EXEC
 128 #define __S111  PAGE_SHARED_EXEC
 129
 130 #ifndef __ASSEMBLY__
 131
 132 /*
 133  * ZERO_PAGE is a global shared page that is always zero: used
 134  * for zero-mapped memory areas etc..
 135  */
 136 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 137 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 138
 139 extern spinlock_t pgd_lock;
 140 extern struct list_head pgd_list;
 141
 142 /*
 143  * The following only work if pte_present() is true.
 144  * Undefined behaviour if not..
 145  */
 146 static inline int pte_dirty(pte_t pte)
 147 {
 148         return pte_flags(pte) & _PAGE_DIRTY;
 149 }
 150
 151 static inline int pte_young(pte_t pte)
 152 {
 153         return pte_flags(pte) & _PAGE_ACCESSED;
 154 }
 155
 156 static inline int pte_write(pte_t pte)
 157 {
 158         return pte_flags(pte) & _PAGE_RW;
 159 }
 160
 161 static inline int pte_file(pte_t pte)
 162 {
 163         return pte_flags(pte) & _PAGE_FILE;
 164 }
 165
 166 static inline int pte_huge(pte_t pte)
 167 {
 168         return pte_flags(pte) & _PAGE_PSE;
 169 }
 170
 171 static inline int pte_global(pte_t pte)
 172 {
 173         return pte_flags(pte) & _PAGE_GLOBAL;
 174 }
 175
 176 static inline int pte_exec(pte_t pte)
 177 {
 178         return !(pte_flags(pte) & _PAGE_NX);
 179 }
 180
 181 static inline int pte_special(pte_t pte)
 182 {
 183         return 0;
 184 }
 185
 186 static inline int pmd_large(pmd_t pte)
 187 {
 188         return (pmd_val(pte) & (_PAGE_PSE | _PAGE_PRESENT)) ==
 189                 (_PAGE_PSE | _PAGE_PRESENT);
 190 }
 191
 192 static inline pte_t pte_mkclean(pte_t pte)
 193 {
 194         return __pte(pte_val(pte) & ~_PAGE_DIRTY);
 195 }
 196
 197 static inline pte_t pte_mkold(pte_t pte)
 198 {
 199         return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
 200 }
 201
 202 static inline pte_t pte_wrprotect(pte_t pte)
 203 {
 204         return __pte(pte_val(pte) & ~_PAGE_RW);
 205 }
 206
 207 static inline pte_t pte_mkexec(pte_t pte)
 208 {
 209         return __pte(pte_val(pte) & ~_PAGE_NX);
 210 }
 211
 212 static inline pte_t pte_mkdirty(pte_t pte)
 213 {
 214         return __pte(pte_val(pte) | _PAGE_DIRTY);
 215 }
 216
 217 static inline pte_t pte_mkyoung(pte_t pte)
 218 {
 219         return __pte(pte_val(pte) | _PAGE_ACCESSED);
 220 }
 221
 222 static inline pte_t pte_mkwrite(pte_t pte)
 223 {
 224         return __pte(pte_val(pte) | _PAGE_RW);
 225 }
 226
 227 static inline pte_t pte_mkhuge(pte_t pte)
 228 {
 229         return __pte(pte_val(pte) | _PAGE_PSE);
 230 }
 231
 232 static inline pte_t pte_clrhuge(pte_t pte)
 233 {
 234         return __pte(pte_val(pte) & ~_PAGE_PSE);
 235 }
 236
 237 static inline pte_t pte_mkglobal(pte_t pte)
 238 {
 239         return __pte(pte_val(pte) | _PAGE_GLOBAL);
 240 }
 241
 242 static inline pte_t pte_clrglobal(pte_t pte)
 243 {
 244         return __pte(pte_val(pte) & ~_PAGE_GLOBAL);
 245 }
 246
 247 static inline pte_t pte_mkspecial(pte_t pte)
 248 {
 249         return pte;
 250 }
 251
 252 extern pteval_t __supported_pte_mask;
 253
 254 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 255 {
 256         return __pte((((phys_addr_t)page_nr << PAGE_SHIFT) |
 257                       pgprot_val(pgprot)) & __supported_pte_mask);
 258 }
 259
 260 static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 261 {
 262         return __pmd((((phys_addr_t)page_nr << PAGE_SHIFT) |
 263                       pgprot_val(pgprot)) & __supported_pte_mask);
 264 }
 265
 266 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 267 {
 268         pteval_t val = pte_val(pte);
 269
 270         /*
 271          * Chop off the NX bit (if present), and add the NX portion of
 272          * the newprot (if present):
 273          */
 274         val &= _PAGE_CHG_MASK;
 275         val |= pgprot_val(newprot) & (~_PAGE_CHG_MASK) & __supported_pte_mask;
 276
 277         return __pte(val);
 278 }
 279
 280 /* mprotect needs to preserve PAT bits when updating vm_page_prot */
 281 #define pgprot_modify pgprot_modify
 282 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 283 {
 284         pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK;
 285         pgprotval_t addbits = pgprot_val(newprot);
 286         return __pgprot(preservebits | addbits);
 287 }
 288
 289 #define pte_pgprot(x) __pgprot(pte_flags(x) & ~PTE_PFN_MASK)
 290
 291 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
 292
 293 #ifndef __ASSEMBLY__
 294 #define __HAVE_PHYS_MEM_ACCESS_PROT
 295 struct file;
 296 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 297                               unsigned long size, pgprot_t vma_prot);
 298 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 299                               unsigned long size, pgprot_t *vma_prot);
 300 #endif
 301
 302 /* Install a pte for a particular vaddr in kernel space. */
 303 void set_pte_vaddr(unsigned long vaddr, pte_t pte);
 304
 305 #ifdef CONFIG_X86_32
 306 extern void native_pagetable_setup_start(pgd_t *base);
 307 extern void native_pagetable_setup_done(pgd_t *base);
 308 #else
 309 static inline void native_pagetable_setup_start(pgd_t *base) {}
 310 static inline void native_pagetable_setup_done(pgd_t *base) {}
 311 #endif
 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
 345 static inline void __init paravirt_pagetable_setup_start(pgd_t *base)
 346 {
 347         native_pagetable_setup_start(base);
 348 }
 349
 350 static inline void __init paravirt_pagetable_setup_done(pgd_t *base)
 351 {
 352         native_pagetable_setup_done(base);
 353 }
 354 #endif  /* CONFIG_PARAVIRT */
 355
 356 #endif  /* __ASSEMBLY__ */
 357
 358 #ifdef CONFIG_X86_32
 359 # include "pgtable_32.h"
 360 #else
 361 # include "pgtable_64.h"
 362 #endif
 363
 364 /*
 365  * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
 366  *
 367  * this macro returns the index of the entry in the pgd page which would
 368  * control the given virtual address
 369  */
 370 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 371
 372 /*
 373  * pgd_offset() returns a (pgd_t *)
 374  * pgd_index() is used get the offset into the pgd page's array of pgd_t's;
 375  */
 376 #define pgd_offset(mm, address) ((mm)->pgd + pgd_index((address)))
 377 /*
 378  * a shortcut which implies the use of the kernel's pgd, instead
 379  * of a process's
 380  */
 381 #define pgd_offset_k(address) pgd_offset(&init_mm, (address))
 382
 383
 384 #define KERNEL_PGD_BOUNDARY     pgd_index(PAGE_OFFSET)
 385 #define KERNEL_PGD_PTRS         (PTRS_PER_PGD - KERNEL_PGD_BOUNDARY)
 386
 387 #ifndef __ASSEMBLY__
 388
 389 enum {
 390         PG_LEVEL_NONE,
 391         PG_LEVEL_4K,
 392         PG_LEVEL_2M,
 393         PG_LEVEL_1G,
 394         PG_LEVEL_NUM
 395 };
 396
 397 #ifdef CONFIG_PROC_FS
 398 extern void update_page_count(int level, unsigned long pages);
 399 #else
 400 static inline void update_page_count(int level, unsigned long pages) { }
 401 #endif
 402
 403 /*
 404  * Helper function that returns the kernel pagetable entry controlling
 405  * the virtual address 'address'. NULL means no pagetable entry present.
 406  * NOTE: the return type is pte_t but if the pmd is PSE then we return it
 407  * as a pte too.
 408  */
 409 extern pte_t *lookup_address(unsigned long address, unsigned int *level);
 410
 411 /* local pte updates need not use xchg for locking */
 412 static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
 413 {
 414         pte_t res = *ptep;
 415
 416         /* Pure native function needs no input for mm, addr */
 417         native_pte_clear(NULL, 0, ptep);
 418         return res;
 419 }
 420
 421 static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
 422                                      pte_t *ptep , pte_t pte)
 423 {
 424         native_set_pte(ptep, pte);
 425 }
 426
 427 #ifndef CONFIG_PARAVIRT
 428 /*
 429  * Rules for using pte_update - it must be called after any PTE update which
 430  * has not been done using the set_pte / clear_pte interfaces.  It is used by
 431  * shadow mode hypervisors to resynchronize the shadow page tables.  Kernel PTE
 432  * updates should either be sets, clears, or set_pte_atomic for P->P
 433  * transitions, which means this hook should only be called for user PTEs.
 434  * This hook implies a P->P protection or access change has taken place, which
 435  * requires a subsequent TLB flush.  The notification can optionally be delayed
 436  * until the TLB flush event by using the pte_update_defer form of the
 437  * interface, but care must be taken to assure that the flush happens while
 438  * still holding the same page table lock so that the shadow and primary pages
 439  * do not become out of sync on SMP.
 440  */
 441 #define pte_update(mm, addr, ptep)              do { } while (0)
 442 #define pte_update_defer(mm, addr, ptep)        do { } while (0)
 443 #endif
 444
 445 /*
 446  * We only update the dirty/accessed state if we set
 447  * the dirty bit by hand in the kernel, since the hardware
 448  * will do the accessed bit for us, and we don't want to
 449  * race with other CPU's that might be updating the dirty
 450  * bit at the same time.
 451  */
 452 struct vm_area_struct;
 453
 454 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 455 extern int ptep_set_access_flags(struct vm_area_struct *vma,
 456                                  unsigned long address, pte_t *ptep,
 457                                  pte_t entry, int dirty);
 458
 459 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 460 extern int ptep_test_and_clear_young(struct vm_area_struct *vma,
 461                                      unsigned long addr, pte_t *ptep);
 462
 463 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 464 extern int ptep_clear_flush_young(struct vm_area_struct *vma,
 465                                   unsigned long address, pte_t *ptep);
 466
 467 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 468 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 469                                        pte_t *ptep)
 470 {
 471         pte_t pte = native_ptep_get_and_clear(ptep);
 472         pte_update(mm, addr, ptep);
 473         return pte;
 474 }
 475
 476 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 477 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 478                                             unsigned long addr, pte_t *ptep,
 479                                             int full)
 480 {
 481         pte_t pte;
 482         if (full) {
 483                 /*
 484                  * Full address destruction in progress; paravirt does not
 485                  * care about updates and native needs no locking
 486                  */
 487                 pte = native_local_ptep_get_and_clear(ptep);
 488         } else {
 489                 pte = ptep_get_and_clear(mm, addr, ptep);
 490         }
 491         return pte;
 492 }
 493
 494 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 495 static inline void ptep_set_wrprotect(struct mm_struct *mm,
 496                                       unsigned long addr, pte_t *ptep)
 497 {
 498         clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
 499         pte_update(mm, addr, ptep);
 500 }
 501
 502 /*
 503  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
 504  *
 505  *  dst - pointer to pgd range anwhere on a pgd page
 506  *  src - ""
 507  *  count - the number of pgds to copy.
 508  *
 509  * dst and src can be on the same page, but the range must not overlap,
 510  * and must not cross a page boundary.
 511  */
 512 static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
 513 {
 514        memcpy(dst, src, count * sizeof(pgd_t));
 515 }
 516
 517
 518 #include <asm-generic/pgtable.h>
 519 #endif  /* __ASSEMBLY__ */
 520
 521 #endif  /* _ASM_X86_PGTABLE_H */