include/asm-generic/pgtable.h

   1 #ifndef _ASM_GENERIC_PGTABLE_H
   2 #define _ASM_GENERIC_PGTABLE_H
   3
   4 #ifndef __ASSEMBLY__
   5 #ifdef CONFIG_MMU
   6
   7 #include <linux/mm_types.h>
   8 #include <linux/bug.h>
   9
  10 /*
  11  * On almost all architectures and configurations, 0 can be used as the
  12  * upper ceiling to free_pgtables(): on many architectures it has the same
  13  * effect as using TASK_SIZE.  However, there is one configuration which
  14  * must impose a more careful limit, to avoid freeing kernel pgtables.
  15  */
  16 #ifndef USER_PGTABLES_CEILING
  17 #define USER_PGTABLES_CEILING   0UL
  18 #endif
  19
  20 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  21 extern int ptep_set_access_flags(struct vm_area_struct *vma,
  22                                  unsigned long address, pte_t *ptep,
  23                                  pte_t entry, int dirty);
  24 #endif
  25
  26 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  27 extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  28                                  unsigned long address, pmd_t *pmdp,
  29                                  pmd_t entry, int dirty);
  30 #endif
  31
  32 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  33 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
  34                                             unsigned long address,
  35                                             pte_t *ptep)
  36 {
  37         pte_t pte = *ptep;
  38         int r = 1;
  39         if (!pte_young(pte))
  40                 r = 0;
  41         else
  42                 set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
  43         return r;
  44 }
  45 #endif
  46
  47 #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
  48 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  49 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  50                                             unsigned long address,
  51                                             pmd_t *pmdp)
  52 {
  53         pmd_t pmd = *pmdp;
  54         int r = 1;
  55         if (!pmd_young(pmd))
  56                 r = 0;
  57         else
  58                 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
  59         return r;
  60 }
  61 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
  62 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  63                                             unsigned long address,
  64                                             pmd_t *pmdp)
  65 {
  66         BUG();
  67         return 0;
  68 }
  69 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  70 #endif
  71
  72 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  73 int ptep_clear_flush_young(struct vm_area_struct *vma,
  74                            unsigned long address, pte_t *ptep);
  75 #endif
  76
  77 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
  78 int pmdp_clear_flush_young(struct vm_area_struct *vma,
  79                            unsigned long address, pmd_t *pmdp);
  80 #endif
  81
  82 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  83 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
  84                                        unsigned long address,
  85                                        pte_t *ptep)
  86 {
  87         pte_t pte = *ptep;
  88         pte_clear(mm, address, ptep);
  89         return pte;
  90 }
  91 #endif
  92
  93 #ifndef __HAVE_ARCH_PMDP_GET_AND_CLEAR
  94 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  95 static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
  96                                        unsigned long address,
  97                                        pmd_t *pmdp)
  98 {
  99         pmd_t pmd = *pmdp;
 100         pmd_clear(pmdp);
 101         return pmd;
 102 }
 103 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 104 #endif
 105
 106 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 107 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 108                                             unsigned long address, pte_t *ptep,
 109                                             int full)
 110 {
 111         pte_t pte;
 112         pte = ptep_get_and_clear(mm, address, ptep);
 113         return pte;
 114 }
 115 #endif
 116
 117 /*
 118  * Some architectures may be able to avoid expensive synchronization
 119  * primitives when modifications are made to PTE's which are already
 120  * not present, or in the process of an address space destruction.
 121  */
 122 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 123 static inline void pte_clear_not_present_full(struct mm_struct *mm,
 124                                               unsigned long address,
 125                                               pte_t *ptep,
 126                                               int full)
 127 {
 128         pte_clear(mm, address, ptep);
 129 }
 130 #endif
 131
 132 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 133 extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
 134                               unsigned long address,
 135                               pte_t *ptep);
 136 #endif
 137
 138 #ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
 139 extern pmd_t pmdp_clear_flush(struct vm_area_struct *vma,
 140                               unsigned long address,
 141                               pmd_t *pmdp);
 142 #endif
 143
 144 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 145 struct mm_struct;
 146 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 147 {
 148         pte_t old_pte = *ptep;
 149         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 150 }
 151 #endif
 152
 153 #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
 154 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 155 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 156                                       unsigned long address, pmd_t *pmdp)
 157 {
 158         pmd_t old_pmd = *pmdp;
 159         set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 160 }
 161 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 162 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 163                                       unsigned long address, pmd_t *pmdp)
 164 {
 165         BUG();
 166 }
 167 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 168 #endif
 169
 170 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 171 extern void pmdp_splitting_flush(struct vm_area_struct *vma,
 172                                  unsigned long address, pmd_t *pmdp);
 173 #endif
 174
 175 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 176 extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 177                                        pgtable_t pgtable);
 178 #endif
 179
 180 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 181 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 182 #endif
 183
 184 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 185 extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 186                             pmd_t *pmdp);
 187 #endif
 188
 189 #ifndef __HAVE_ARCH_PTE_SAME
 190 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 191 {
 192         return pte_val(pte_a) == pte_val(pte_b);
 193 }
 194 #endif
 195
 196 #ifndef __HAVE_ARCH_PMD_SAME
 197 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 198 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 199 {
 200         return pmd_val(pmd_a) == pmd_val(pmd_b);
 201 }
 202 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 203 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 204 {
 205         BUG();
 206         return 0;
 207 }
 208 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 209 #endif
 210
 211 #ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 212 #define page_test_and_clear_young(pfn) (0)
 213 #endif
 214
 215 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 216 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 217 #endif
 218
 219 #ifndef __HAVE_ARCH_MOVE_PTE
 220 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 221 #endif
 222
 223 #ifndef pte_accessible
 224 # define pte_accessible(pte)            ((void)(pte),1)
 225 #endif
 226
 227 #ifndef flush_tlb_fix_spurious_fault
 228 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 229 #endif
 230
 231 #ifndef pgprot_noncached
 232 #define pgprot_noncached(prot)  (prot)
 233 #endif
 234
 235 #ifndef pgprot_writecombine
 236 #define pgprot_writecombine pgprot_noncached
 237 #endif
 238
 239 /*
 240  * When walking page tables, get the address of the next boundary,
 241  * or the end address of the range if that comes earlier.  Although no
 242  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 243  */
 244
 245 #define pgd_addr_end(addr, end)                                         \
 246 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 247         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 248 })
 249
 250 #ifndef pud_addr_end
 251 #define pud_addr_end(addr, end)                                         \
 252 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 253         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 254 })
 255 #endif
 256
 257 #ifndef pmd_addr_end
 258 #define pmd_addr_end(addr, end)                                         \
 259 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 260         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 261 })
 262 #endif
 263
 264 /*
 265  * When walking page tables, we usually want to skip any p?d_none entries;
 266  * and any p?d_bad entries - reporting the error before resetting to none.
 267  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 268  */
 269 void pgd_clear_bad(pgd_t *);
 270 void pud_clear_bad(pud_t *);
 271 void pmd_clear_bad(pmd_t *);
 272
 273 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 274 {
 275         if (pgd_none(*pgd))
 276                 return 1;
 277         if (unlikely(pgd_bad(*pgd))) {
 278                 pgd_clear_bad(pgd);
 279                 return 1;
 280         }
 281         return 0;
 282 }
 283
 284 static inline int pud_none_or_clear_bad(pud_t *pud)
 285 {
 286         if (pud_none(*pud))
 287                 return 1;
 288         if (unlikely(pud_bad(*pud))) {
 289                 pud_clear_bad(pud);
 290                 return 1;
 291         }
 292         return 0;
 293 }
 294
 295 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 296 {
 297         if (pmd_none(*pmd))
 298                 return 1;
 299         if (unlikely(pmd_bad(*pmd))) {
 300                 pmd_clear_bad(pmd);
 301                 return 1;
 302         }
 303         return 0;
 304 }
 305
 306 static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
 307                                              unsigned long addr,
 308                                              pte_t *ptep)
 309 {
 310         /*
 311          * Get the current pte state, but zero it out to make it
 312          * non-present, preventing the hardware from asynchronously
 313          * updating it.
 314          */
 315         return ptep_get_and_clear(mm, addr, ptep);
 316 }
 317
 318 static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
 319                                              unsigned long addr,
 320                                              pte_t *ptep, pte_t pte)
 321 {
 322         /*
 323          * The pte is non-present, so there's no hardware state to
 324          * preserve.
 325          */
 326         set_pte_at(mm, addr, ptep, pte);
 327 }
 328
 329 #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 330 /*
 331  * Start a pte protection read-modify-write transaction, which
 332  * protects against asynchronous hardware modifications to the pte.
 333  * The intention is not to prevent the hardware from making pte
 334  * updates, but to prevent any updates it may make from being lost.
 335  *
 336  * This does not protect against other software modifications of the
 337  * pte; the appropriate pte lock must be held over the transation.
 338  *
 339  * Note that this interface is intended to be batchable, meaning that
 340  * ptep_modify_prot_commit may not actually update the pte, but merely
 341  * queue the update to be done at some later time.  The update must be
 342  * actually committed before the pte lock is released, however.
 343  */
 344 static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
 345                                            unsigned long addr,
 346                                            pte_t *ptep)
 347 {
 348         return __ptep_modify_prot_start(mm, addr, ptep);
 349 }
 350
 351 /*
 352  * Commit an update to a pte, leaving any hardware-controlled bits in
 353  * the PTE unmodified.
 354  */
 355 static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 356                                            unsigned long addr,
 357                                            pte_t *ptep, pte_t pte)
 358 {
 359         __ptep_modify_prot_commit(mm, addr, ptep, pte);
 360 }
 361 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 362 #endif /* CONFIG_MMU */
 363
 364 /*
 365  * A facility to provide lazy MMU batching.  This allows PTE updates and
 366  * page invalidations to be delayed until a call to leave lazy MMU mode
 367  * is issued.  Some architectures may benefit from doing this, and it is
 368  * beneficial for both shadow and direct mode hypervisors, which may batch
 369  * the PTE updates which happen during this window.  Note that using this
 370  * interface requires that read hazards be removed from the code.  A read
 371  * hazard could result in the direct mode hypervisor case, since the actual
 372  * write to the page tables may not yet have taken place, so reads though
 373  * a raw PTE pointer after it has been modified are not guaranteed to be
 374  * up to date.  This mode can only be entered and left under the protection of
 375  * the page table locks for all page tables which may be modified.  In the UP
 376  * case, this is required so that preemption is disabled, and in the SMP case,
 377  * it must synchronize the delayed page table writes properly on other CPUs.
 378  */
 379 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 380 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 381 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 382 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 383 #endif
 384
 385 /*
 386  * A facility to provide batching of the reload of page tables and
 387  * other process state with the actual context switch code for
 388  * paravirtualized guests.  By convention, only one of the batched
 389  * update (lazy) modes (CPU, MMU) should be active at any given time,
 390  * entry should never be nested, and entry and exits should always be
 391  * paired.  This is for sanity of maintaining and reasoning about the
 392  * kernel code.  In this case, the exit (end of the context switch) is
 393  * in architecture-specific code, and so doesn't need a generic
 394  * definition.
 395  */
 396 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 397 #define arch_start_context_switch(prev) do {} while (0)
 398 #endif
 399
 400 #ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
 401 static inline int pte_soft_dirty(pte_t pte)
 402 {
 403         return 0;
 404 }
 405
 406 static inline int pmd_soft_dirty(pmd_t pmd)
 407 {
 408         return 0;
 409 }
 410
 411 static inline pte_t pte_mksoft_dirty(pte_t pte)
 412 {
 413         return pte;
 414 }
 415
 416 static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 417 {
 418         return pmd;
 419 }
 420
 421 static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 422 {
 423         return pte;
 424 }
 425
 426 static inline int pte_swp_soft_dirty(pte_t pte)
 427 {
 428         return 0;
 429 }
 430
 431 static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 432 {
 433         return pte;
 434 }
 435 #endif
 436
 437 #ifndef __HAVE_PFNMAP_TRACKING
 438 /*
 439  * Interfaces that can be used by architecture code to keep track of
 440  * memory type of pfn mappings specified by the remap_pfn_range,
 441  * vm_insert_pfn.
 442  */
 443
 444 /*
 445  * track_pfn_remap is called when a _new_ pfn mapping is being established
 446  * by remap_pfn_range() for physical range indicated by pfn and size.
 447  */
 448 static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 449                                   unsigned long pfn, unsigned long addr,
 450                                   unsigned long size)
 451 {
 452         return 0;
 453 }
 454
 455 /*
 456  * track_pfn_insert is called when a _new_ single pfn is established
 457  * by vm_insert_pfn().
 458  */
 459 static inline int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 460                                    unsigned long pfn)
 461 {
 462         return 0;
 463 }
 464
 465 /*
 466  * track_pfn_copy is called when vma that is covering the pfnmap gets
 467  * copied through copy_page_range().
 468  */
 469 static inline int track_pfn_copy(struct vm_area_struct *vma)
 470 {
 471         return 0;
 472 }
 473
 474 /*
 475  * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 476  * untrack can be called for a specific region indicated by pfn and size or
 477  * can be for the entire vma (in which case pfn, size are zero).
 478  */
 479 static inline void untrack_pfn(struct vm_area_struct *vma,
 480                                unsigned long pfn, unsigned long size)
 481 {
 482 }
 483 #else
 484 extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 485                            unsigned long pfn, unsigned long addr,
 486                            unsigned long size);
 487 extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 488                             unsigned long pfn);
 489 extern int track_pfn_copy(struct vm_area_struct *vma);
 490 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 491                         unsigned long size);
 492 #endif
 493
 494 #ifdef __HAVE_COLOR_ZERO_PAGE
 495 static inline int is_zero_pfn(unsigned long pfn)
 496 {
 497         extern unsigned long zero_pfn;
 498         unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 499         return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 500 }
 501
 502 #define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 503
 504 #else
 505 static inline int is_zero_pfn(unsigned long pfn)
 506 {
 507         extern unsigned long zero_pfn;
 508         return pfn == zero_pfn;
 509 }
 510
 511 static inline unsigned long my_zero_pfn(unsigned long addr)
 512 {
 513         extern unsigned long zero_pfn;
 514         return zero_pfn;
 515 }
 516 #endif
 517
 518 #ifdef CONFIG_MMU
 519
 520 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 521 static inline int pmd_trans_huge(pmd_t pmd)
 522 {
 523         return 0;
 524 }
 525 static inline int pmd_trans_splitting(pmd_t pmd)
 526 {
 527         return 0;
 528 }
 529 #ifndef __HAVE_ARCH_PMD_WRITE
 530 static inline int pmd_write(pmd_t pmd)
 531 {
 532         BUG();
 533         return 0;
 534 }
 535 #endif /* __HAVE_ARCH_PMD_WRITE */
 536 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 537
 538 #ifndef pmd_read_atomic
 539 static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 540 {
 541         /*
 542          * Depend on compiler for an atomic pmd read. NOTE: this is
 543          * only going to work, if the pmdval_t isn't larger than
 544          * an unsigned long.
 545          */
 546         return *pmdp;
 547 }
 548 #endif
 549
 550 /*
 551  * This function is meant to be used by sites walking pagetables with
 552  * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 553  * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 554  * into a null pmd and the transhuge page fault can convert a null pmd
 555  * into an hugepmd or into a regular pmd (if the hugepage allocation
 556  * fails). While holding the mmap_sem in read mode the pmd becomes
 557  * stable and stops changing under us only if it's not null and not a
 558  * transhuge pmd. When those races occurs and this function makes a
 559  * difference vs the standard pmd_none_or_clear_bad, the result is
 560  * undefined so behaving like if the pmd was none is safe (because it
 561  * can return none anyway). The compiler level barrier() is critically
 562  * important to compute the two checks atomically on the same pmdval.
 563  *
 564  * For 32bit kernels with a 64bit large pmd_t this automatically takes
 565  * care of reading the pmd atomically to avoid SMP race conditions
 566  * against pmd_populate() when the mmap_sem is hold for reading by the
 567  * caller (a special atomic read not done by "gcc" as in the generic
 568  * version above, is also needed when THP is disabled because the page
 569  * fault can populate the pmd from under us).
 570  */
 571 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 572 {
 573         pmd_t pmdval = pmd_read_atomic(pmd);
 574         /*
 575          * The barrier will stabilize the pmdval in a register or on
 576          * the stack so that it will stop changing under the code.
 577          *
 578          * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 579          * pmd_read_atomic is allowed to return a not atomic pmdval
 580          * (for example pointing to an hugepage that has never been
 581          * mapped in the pmd). The below checks will only care about
 582          * the low part of the pmd with 32bit PAE x86 anyway, with the
 583          * exception of pmd_none(). So the important thing is that if
 584          * the low part of the pmd is found null, the high part will
 585          * be also null or the pmd_none() check below would be
 586          * confused.
 587          */
 588 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 589         barrier();
 590 #endif
 591         if (pmd_none(pmdval))
 592                 return 1;
 593         if (unlikely(pmd_bad(pmdval))) {
 594                 if (!pmd_trans_huge(pmdval))
 595                         pmd_clear_bad(pmd);
 596                 return 1;
 597         }
 598         return 0;
 599 }
 600
 601 /*
 602  * This is a noop if Transparent Hugepage Support is not built into
 603  * the kernel. Otherwise it is equivalent to
 604  * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 605  * places that already verified the pmd is not none and they want to
 606  * walk ptes while holding the mmap sem in read mode (write mode don't
 607  * need this). If THP is not enabled, the pmd can't go away under the
 608  * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 609  * run a pmd_trans_unstable before walking the ptes after
 610  * split_huge_page_pmd returns (because it may have run when the pmd
 611  * become null, but then a page fault can map in a THP and not a
 612  * regular page).
 613  */
 614 static inline int pmd_trans_unstable(pmd_t *pmd)
 615 {
 616 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 617         return pmd_none_or_trans_huge_or_clear_bad(pmd);
 618 #else
 619         return 0;
 620 #endif
 621 }
 622
 623 #ifdef CONFIG_NUMA_BALANCING
 624 #ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
 625 /*
 626  * _PAGE_NUMA works identical to _PAGE_PROTNONE (it's actually the
 627  * same bit too). It's set only when _PAGE_PRESET is not set and it's
 628  * never set if _PAGE_PRESENT is set.
 629  *
 630  * pte/pmd_present() returns true if pte/pmd_numa returns true. Page
 631  * fault triggers on those regions if pte/pmd_numa returns true
 632  * (because _PAGE_PRESENT is not set).
 633  */
 634 #ifndef pte_numa
 635 static inline int pte_numa(pte_t pte)
 636 {
 637         return (pte_flags(pte) &
 638                 (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 639 }
 640 #endif
 641
 642 #ifndef pmd_numa
 643 static inline int pmd_numa(pmd_t pmd)
 644 {
 645         return (pmd_flags(pmd) &
 646                 (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 647 }
 648 #endif
 649
 650 /*
 651  * pte/pmd_mknuma sets the _PAGE_ACCESSED bitflag automatically
 652  * because they're called by the NUMA hinting minor page fault. If we
 653  * wouldn't set the _PAGE_ACCESSED bitflag here, the TLB miss handler
 654  * would be forced to set it later while filling the TLB after we
 655  * return to userland. That would trigger a second write to memory
 656  * that we optimize away by setting _PAGE_ACCESSED here.
 657  */
 658 #ifndef pte_mknonnuma
 659 static inline pte_t pte_mknonnuma(pte_t pte)
 660 {
 661         pte = pte_clear_flags(pte, _PAGE_NUMA);
 662         return pte_set_flags(pte, _PAGE_PRESENT|_PAGE_ACCESSED);
 663 }
 664 #endif
 665
 666 #ifndef pmd_mknonnuma
 667 static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 668 {
 669         pmd = pmd_clear_flags(pmd, _PAGE_NUMA);
 670         return pmd_set_flags(pmd, _PAGE_PRESENT|_PAGE_ACCESSED);
 671 }
 672 #endif
 673
 674 #ifndef pte_mknuma
 675 static inline pte_t pte_mknuma(pte_t pte)
 676 {
 677         pte = pte_set_flags(pte, _PAGE_NUMA);
 678         return pte_clear_flags(pte, _PAGE_PRESENT);
 679 }
 680 #endif
 681
 682 #ifndef pmd_mknuma
 683 static inline pmd_t pmd_mknuma(pmd_t pmd)
 684 {
 685         pmd = pmd_set_flags(pmd, _PAGE_NUMA);
 686         return pmd_clear_flags(pmd, _PAGE_PRESENT);
 687 }
 688 #endif
 689 #else
 690 extern int pte_numa(pte_t pte);
 691 extern int pmd_numa(pmd_t pmd);
 692 extern pte_t pte_mknonnuma(pte_t pte);
 693 extern pmd_t pmd_mknonnuma(pmd_t pmd);
 694 extern pte_t pte_mknuma(pte_t pte);
 695 extern pmd_t pmd_mknuma(pmd_t pmd);
 696 #endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */
 697 #else
 698 static inline int pmd_numa(pmd_t pmd)
 699 {
 700         return 0;
 701 }
 702
 703 static inline int pte_numa(pte_t pte)
 704 {
 705         return 0;
 706 }
 707
 708 static inline pte_t pte_mknonnuma(pte_t pte)
 709 {
 710         return pte;
 711 }
 712
 713 static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 714 {
 715         return pmd;
 716 }
 717
 718 static inline pte_t pte_mknuma(pte_t pte)
 719 {
 720         return pte;
 721 }
 722
 723 static inline pmd_t pmd_mknuma(pmd_t pmd)
 724 {
 725         return pmd;
 726 }
 727 #endif /* CONFIG_NUMA_BALANCING */
 728
 729 #endif /* CONFIG_MMU */
 730
 731 #endif /* !__ASSEMBLY__ */
 732
 733 #ifndef io_remap_pfn_range
 734 #define io_remap_pfn_range remap_pfn_range
 735 #endif
 736
 737 #endif /* _ASM_GENERIC_PGTABLE_H */