linux/include/asm-generic/pgtable.h
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   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
  21extern 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
  27extern 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
  33static 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
  49static 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 */
  62static 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
  73int 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
  78int 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
  83static 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
  95static 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
 107static 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
 123static 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
 133extern 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
 139extern 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
 145struct mm_struct;
 146static 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
 155static 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 */
 162static 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
 171extern 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
 176extern 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
 181extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 182#endif
 183
 184#ifndef __HAVE_ARCH_PMDP_INVALIDATE
 185extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 186                            pmd_t *pmdp);
 187#endif
 188
 189#ifndef __HAVE_ARCH_PTE_SAME
 190static 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
 198static 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 */
 203static 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 */
 269void pgd_clear_bad(pgd_t *);
 270void pud_clear_bad(pud_t *);
 271void pmd_clear_bad(pmd_t *);
 272
 273static 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
 284static 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
 295static 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
 306static 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
 318static 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 */
 344static 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 */
 355static 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
 401static inline int pte_soft_dirty(pte_t pte)
 402{
 403        return 0;
 404}
 405
 406static inline int pmd_soft_dirty(pmd_t pmd)
 407{
 408        return 0;
 409}
 410
 411static inline pte_t pte_mksoft_dirty(pte_t pte)
 412{
 413        return pte;
 414}
 415
 416static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 417{
 418        return pmd;
 419}
 420
 421static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 422{
 423        return pte;
 424}
 425
 426static inline int pte_swp_soft_dirty(pte_t pte)
 427{
 428        return 0;
 429}
 430
 431static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 432{
 433        return pte;
 434}
 435
 436static inline pte_t pte_file_clear_soft_dirty(pte_t pte)
 437{
 438       return pte;
 439}
 440
 441static inline pte_t pte_file_mksoft_dirty(pte_t pte)
 442{
 443       return pte;
 444}
 445
 446static inline int pte_file_soft_dirty(pte_t pte)
 447{
 448       return 0;
 449}
 450#endif
 451
 452#ifndef __HAVE_PFNMAP_TRACKING
 453/*
 454 * Interfaces that can be used by architecture code to keep track of
 455 * memory type of pfn mappings specified by the remap_pfn_range,
 456 * vm_insert_pfn.
 457 */
 458
 459/*
 460 * track_pfn_remap is called when a _new_ pfn mapping is being established
 461 * by remap_pfn_range() for physical range indicated by pfn and size.
 462 */
 463static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 464                                  unsigned long pfn, unsigned long addr,
 465                                  unsigned long size)
 466{
 467        return 0;
 468}
 469
 470/*
 471 * track_pfn_insert is called when a _new_ single pfn is established
 472 * by vm_insert_pfn().
 473 */
 474static inline int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 475                                   unsigned long pfn)
 476{
 477        return 0;
 478}
 479
 480/*
 481 * track_pfn_copy is called when vma that is covering the pfnmap gets
 482 * copied through copy_page_range().
 483 */
 484static inline int track_pfn_copy(struct vm_area_struct *vma)
 485{
 486        return 0;
 487}
 488
 489/*
 490 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 491 * untrack can be called for a specific region indicated by pfn and size or
 492 * can be for the entire vma (in which case pfn, size are zero).
 493 */
 494static inline void untrack_pfn(struct vm_area_struct *vma,
 495                               unsigned long pfn, unsigned long size)
 496{
 497}
 498#else
 499extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 500                           unsigned long pfn, unsigned long addr,
 501                           unsigned long size);
 502extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 503                            unsigned long pfn);
 504extern int track_pfn_copy(struct vm_area_struct *vma);
 505extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 506                        unsigned long size);
 507#endif
 508
 509#ifdef __HAVE_COLOR_ZERO_PAGE
 510static inline int is_zero_pfn(unsigned long pfn)
 511{
 512        extern unsigned long zero_pfn;
 513        unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 514        return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 515}
 516
 517#define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 518
 519#else
 520static inline int is_zero_pfn(unsigned long pfn)
 521{
 522        extern unsigned long zero_pfn;
 523        return pfn == zero_pfn;
 524}
 525
 526static inline unsigned long my_zero_pfn(unsigned long addr)
 527{
 528        extern unsigned long zero_pfn;
 529        return zero_pfn;
 530}
 531#endif
 532
 533#ifdef CONFIG_MMU
 534
 535#ifndef CONFIG_TRANSPARENT_HUGEPAGE
 536static inline int pmd_trans_huge(pmd_t pmd)
 537{
 538        return 0;
 539}
 540static inline int pmd_trans_splitting(pmd_t pmd)
 541{
 542        return 0;
 543}
 544#ifndef __HAVE_ARCH_PMD_WRITE
 545static inline int pmd_write(pmd_t pmd)
 546{
 547        BUG();
 548        return 0;
 549}
 550#endif /* __HAVE_ARCH_PMD_WRITE */
 551#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 552
 553#ifndef pmd_read_atomic
 554static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 555{
 556        /*
 557         * Depend on compiler for an atomic pmd read. NOTE: this is
 558         * only going to work, if the pmdval_t isn't larger than
 559         * an unsigned long.
 560         */
 561        return *pmdp;
 562}
 563#endif
 564
 565/*
 566 * This function is meant to be used by sites walking pagetables with
 567 * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 568 * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 569 * into a null pmd and the transhuge page fault can convert a null pmd
 570 * into an hugepmd or into a regular pmd (if the hugepage allocation
 571 * fails). While holding the mmap_sem in read mode the pmd becomes
 572 * stable and stops changing under us only if it's not null and not a
 573 * transhuge pmd. When those races occurs and this function makes a
 574 * difference vs the standard pmd_none_or_clear_bad, the result is
 575 * undefined so behaving like if the pmd was none is safe (because it
 576 * can return none anyway). The compiler level barrier() is critically
 577 * important to compute the two checks atomically on the same pmdval.
 578 *
 579 * For 32bit kernels with a 64bit large pmd_t this automatically takes
 580 * care of reading the pmd atomically to avoid SMP race conditions
 581 * against pmd_populate() when the mmap_sem is hold for reading by the
 582 * caller (a special atomic read not done by "gcc" as in the generic
 583 * version above, is also needed when THP is disabled because the page
 584 * fault can populate the pmd from under us).
 585 */
 586static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 587{
 588        pmd_t pmdval = pmd_read_atomic(pmd);
 589        /*
 590         * The barrier will stabilize the pmdval in a register or on
 591         * the stack so that it will stop changing under the code.
 592         *
 593         * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 594         * pmd_read_atomic is allowed to return a not atomic pmdval
 595         * (for example pointing to an hugepage that has never been
 596         * mapped in the pmd). The below checks will only care about
 597         * the low part of the pmd with 32bit PAE x86 anyway, with the
 598         * exception of pmd_none(). So the important thing is that if
 599         * the low part of the pmd is found null, the high part will
 600         * be also null or the pmd_none() check below would be
 601         * confused.
 602         */
 603#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 604        barrier();
 605#endif
 606        if (pmd_none(pmdval))
 607                return 1;
 608        if (unlikely(pmd_bad(pmdval))) {
 609                if (!pmd_trans_huge(pmdval))
 610                        pmd_clear_bad(pmd);
 611                return 1;
 612        }
 613        return 0;
 614}
 615
 616/*
 617 * This is a noop if Transparent Hugepage Support is not built into
 618 * the kernel. Otherwise it is equivalent to
 619 * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 620 * places that already verified the pmd is not none and they want to
 621 * walk ptes while holding the mmap sem in read mode (write mode don't
 622 * need this). If THP is not enabled, the pmd can't go away under the
 623 * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 624 * run a pmd_trans_unstable before walking the ptes after
 625 * split_huge_page_pmd returns (because it may have run when the pmd
 626 * become null, but then a page fault can map in a THP and not a
 627 * regular page).
 628 */
 629static inline int pmd_trans_unstable(pmd_t *pmd)
 630{
 631#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 632        return pmd_none_or_trans_huge_or_clear_bad(pmd);
 633#else
 634        return 0;
 635#endif
 636}
 637
 638#ifdef CONFIG_NUMA_BALANCING
 639#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
 640/*
 641 * _PAGE_NUMA works identical to _PAGE_PROTNONE (it's actually the
 642 * same bit too). It's set only when _PAGE_PRESET is not set and it's
 643 * never set if _PAGE_PRESENT is set.
 644 *
 645 * pte/pmd_present() returns true if pte/pmd_numa returns true. Page
 646 * fault triggers on those regions if pte/pmd_numa returns true
 647 * (because _PAGE_PRESENT is not set).
 648 */
 649#ifndef pte_numa
 650static inline int pte_numa(pte_t pte)
 651{
 652        return (pte_flags(pte) &
 653                (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 654}
 655#endif
 656
 657#ifndef pmd_numa
 658static inline int pmd_numa(pmd_t pmd)
 659{
 660        return (pmd_flags(pmd) &
 661                (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 662}
 663#endif
 664
 665/*
 666 * pte/pmd_mknuma sets the _PAGE_ACCESSED bitflag automatically
 667 * because they're called by the NUMA hinting minor page fault. If we
 668 * wouldn't set the _PAGE_ACCESSED bitflag here, the TLB miss handler
 669 * would be forced to set it later while filling the TLB after we
 670 * return to userland. That would trigger a second write to memory
 671 * that we optimize away by setting _PAGE_ACCESSED here.
 672 */
 673#ifndef pte_mknonnuma
 674static inline pte_t pte_mknonnuma(pte_t pte)
 675{
 676        pte = pte_clear_flags(pte, _PAGE_NUMA);
 677        return pte_set_flags(pte, _PAGE_PRESENT|_PAGE_ACCESSED);
 678}
 679#endif
 680
 681#ifndef pmd_mknonnuma
 682static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 683{
 684        pmd = pmd_clear_flags(pmd, _PAGE_NUMA);
 685        return pmd_set_flags(pmd, _PAGE_PRESENT|_PAGE_ACCESSED);
 686}
 687#endif
 688
 689#ifndef pte_mknuma
 690static inline pte_t pte_mknuma(pte_t pte)
 691{
 692        pte = pte_set_flags(pte, _PAGE_NUMA);
 693        return pte_clear_flags(pte, _PAGE_PRESENT);
 694}
 695#endif
 696
 697#ifndef pmd_mknuma
 698static inline pmd_t pmd_mknuma(pmd_t pmd)
 699{
 700        pmd = pmd_set_flags(pmd, _PAGE_NUMA);
 701        return pmd_clear_flags(pmd, _PAGE_PRESENT);
 702}
 703#endif
 704#else
 705extern int pte_numa(pte_t pte);
 706extern int pmd_numa(pmd_t pmd);
 707extern pte_t pte_mknonnuma(pte_t pte);
 708extern pmd_t pmd_mknonnuma(pmd_t pmd);
 709extern pte_t pte_mknuma(pte_t pte);
 710extern pmd_t pmd_mknuma(pmd_t pmd);
 711#endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */
 712#else
 713static inline int pmd_numa(pmd_t pmd)
 714{
 715        return 0;
 716}
 717
 718static inline int pte_numa(pte_t pte)
 719{
 720        return 0;
 721}
 722
 723static inline pte_t pte_mknonnuma(pte_t pte)
 724{
 725        return pte;
 726}
 727
 728static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 729{
 730        return pmd;
 731}
 732
 733static inline pte_t pte_mknuma(pte_t pte)
 734{
 735        return pte;
 736}
 737
 738static inline pmd_t pmd_mknuma(pmd_t pmd)
 739{
 740        return pmd;
 741}
 742#endif /* CONFIG_NUMA_BALANCING */
 743
 744#endif /* CONFIG_MMU */
 745
 746#endif /* !__ASSEMBLY__ */
 747
 748#ifndef io_remap_pfn_range
 749#define io_remap_pfn_range remap_pfn_range
 750#endif
 751
 752#endif /* _ASM_GENERIC_PGTABLE_H */
 753