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_PGD_OFFSET_GATE
 212#define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 213#endif
 214
 215#ifndef __HAVE_ARCH_MOVE_PTE
 216#define move_pte(pte, prot, old_addr, new_addr) (pte)
 217#endif
 218
 219#ifndef pte_accessible
 220# define pte_accessible(pte)            ((void)(pte),1)
 221#endif
 222
 223#ifndef flush_tlb_fix_spurious_fault
 224#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 225#endif
 226
 227#ifndef pgprot_noncached
 228#define pgprot_noncached(prot)  (prot)
 229#endif
 230
 231#ifndef pgprot_writecombine
 232#define pgprot_writecombine pgprot_noncached
 233#endif
 234
 235/*
 236 * When walking page tables, get the address of the next boundary,
 237 * or the end address of the range if that comes earlier.  Although no
 238 * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 239 */
 240
 241#define pgd_addr_end(addr, end)                                         \
 242({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 243        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 244})
 245
 246#ifndef pud_addr_end
 247#define pud_addr_end(addr, end)                                         \
 248({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 249        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 250})
 251#endif
 252
 253#ifndef pmd_addr_end
 254#define pmd_addr_end(addr, end)                                         \
 255({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 256        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 257})
 258#endif
 259
 260/*
 261 * When walking page tables, we usually want to skip any p?d_none entries;
 262 * and any p?d_bad entries - reporting the error before resetting to none.
 263 * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 264 */
 265void pgd_clear_bad(pgd_t *);
 266void pud_clear_bad(pud_t *);
 267void pmd_clear_bad(pmd_t *);
 268
 269static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 270{
 271        if (pgd_none(*pgd))
 272                return 1;
 273        if (unlikely(pgd_bad(*pgd))) {
 274                pgd_clear_bad(pgd);
 275                return 1;
 276        }
 277        return 0;
 278}
 279
 280static inline int pud_none_or_clear_bad(pud_t *pud)
 281{
 282        if (pud_none(*pud))
 283                return 1;
 284        if (unlikely(pud_bad(*pud))) {
 285                pud_clear_bad(pud);
 286                return 1;
 287        }
 288        return 0;
 289}
 290
 291static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 292{
 293        if (pmd_none(*pmd))
 294                return 1;
 295        if (unlikely(pmd_bad(*pmd))) {
 296                pmd_clear_bad(pmd);
 297                return 1;
 298        }
 299        return 0;
 300}
 301
 302static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
 303                                             unsigned long addr,
 304                                             pte_t *ptep)
 305{
 306        /*
 307         * Get the current pte state, but zero it out to make it
 308         * non-present, preventing the hardware from asynchronously
 309         * updating it.
 310         */
 311        return ptep_get_and_clear(mm, addr, ptep);
 312}
 313
 314static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
 315                                             unsigned long addr,
 316                                             pte_t *ptep, pte_t pte)
 317{
 318        /*
 319         * The pte is non-present, so there's no hardware state to
 320         * preserve.
 321         */
 322        set_pte_at(mm, addr, ptep, pte);
 323}
 324
 325#ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 326/*
 327 * Start a pte protection read-modify-write transaction, which
 328 * protects against asynchronous hardware modifications to the pte.
 329 * The intention is not to prevent the hardware from making pte
 330 * updates, but to prevent any updates it may make from being lost.
 331 *
 332 * This does not protect against other software modifications of the
 333 * pte; the appropriate pte lock must be held over the transation.
 334 *
 335 * Note that this interface is intended to be batchable, meaning that
 336 * ptep_modify_prot_commit may not actually update the pte, but merely
 337 * queue the update to be done at some later time.  The update must be
 338 * actually committed before the pte lock is released, however.
 339 */
 340static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
 341                                           unsigned long addr,
 342                                           pte_t *ptep)
 343{
 344        return __ptep_modify_prot_start(mm, addr, ptep);
 345}
 346
 347/*
 348 * Commit an update to a pte, leaving any hardware-controlled bits in
 349 * the PTE unmodified.
 350 */
 351static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 352                                           unsigned long addr,
 353                                           pte_t *ptep, pte_t pte)
 354{
 355        __ptep_modify_prot_commit(mm, addr, ptep, pte);
 356}
 357#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 358#endif /* CONFIG_MMU */
 359
 360/*
 361 * A facility to provide lazy MMU batching.  This allows PTE updates and
 362 * page invalidations to be delayed until a call to leave lazy MMU mode
 363 * is issued.  Some architectures may benefit from doing this, and it is
 364 * beneficial for both shadow and direct mode hypervisors, which may batch
 365 * the PTE updates which happen during this window.  Note that using this
 366 * interface requires that read hazards be removed from the code.  A read
 367 * hazard could result in the direct mode hypervisor case, since the actual
 368 * write to the page tables may not yet have taken place, so reads though
 369 * a raw PTE pointer after it has been modified are not guaranteed to be
 370 * up to date.  This mode can only be entered and left under the protection of
 371 * the page table locks for all page tables which may be modified.  In the UP
 372 * case, this is required so that preemption is disabled, and in the SMP case,
 373 * it must synchronize the delayed page table writes properly on other CPUs.
 374 */
 375#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 376#define arch_enter_lazy_mmu_mode()      do {} while (0)
 377#define arch_leave_lazy_mmu_mode()      do {} while (0)
 378#define arch_flush_lazy_mmu_mode()      do {} while (0)
 379#endif
 380
 381/*
 382 * A facility to provide batching of the reload of page tables and
 383 * other process state with the actual context switch code for
 384 * paravirtualized guests.  By convention, only one of the batched
 385 * update (lazy) modes (CPU, MMU) should be active at any given time,
 386 * entry should never be nested, and entry and exits should always be
 387 * paired.  This is for sanity of maintaining and reasoning about the
 388 * kernel code.  In this case, the exit (end of the context switch) is
 389 * in architecture-specific code, and so doesn't need a generic
 390 * definition.
 391 */
 392#ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 393#define arch_start_context_switch(prev) do {} while (0)
 394#endif
 395
 396#ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
 397static inline int pte_soft_dirty(pte_t pte)
 398{
 399        return 0;
 400}
 401
 402static inline int pmd_soft_dirty(pmd_t pmd)
 403{
 404        return 0;
 405}
 406
 407static inline pte_t pte_mksoft_dirty(pte_t pte)
 408{
 409        return pte;
 410}
 411
 412static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 413{
 414        return pmd;
 415}
 416
 417static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 418{
 419        return pte;
 420}
 421
 422static inline int pte_swp_soft_dirty(pte_t pte)
 423{
 424        return 0;
 425}
 426
 427static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 428{
 429        return pte;
 430}
 431
 432static inline pte_t pte_file_clear_soft_dirty(pte_t pte)
 433{
 434       return pte;
 435}
 436
 437static inline pte_t pte_file_mksoft_dirty(pte_t pte)
 438{
 439       return pte;
 440}
 441
 442static inline int pte_file_soft_dirty(pte_t pte)
 443{
 444       return 0;
 445}
 446#endif
 447
 448#ifndef __HAVE_PFNMAP_TRACKING
 449/*
 450 * Interfaces that can be used by architecture code to keep track of
 451 * memory type of pfn mappings specified by the remap_pfn_range,
 452 * vm_insert_pfn.
 453 */
 454
 455/*
 456 * track_pfn_remap is called when a _new_ pfn mapping is being established
 457 * by remap_pfn_range() for physical range indicated by pfn and size.
 458 */
 459static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 460                                  unsigned long pfn, unsigned long addr,
 461                                  unsigned long size)
 462{
 463        return 0;
 464}
 465
 466/*
 467 * track_pfn_insert is called when a _new_ single pfn is established
 468 * by vm_insert_pfn().
 469 */
 470static inline int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 471                                   unsigned long pfn)
 472{
 473        return 0;
 474}
 475
 476/*
 477 * track_pfn_copy is called when vma that is covering the pfnmap gets
 478 * copied through copy_page_range().
 479 */
 480static inline int track_pfn_copy(struct vm_area_struct *vma)
 481{
 482        return 0;
 483}
 484
 485/*
 486 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 487 * untrack can be called for a specific region indicated by pfn and size or
 488 * can be for the entire vma (in which case pfn, size are zero).
 489 */
 490static inline void untrack_pfn(struct vm_area_struct *vma,
 491                               unsigned long pfn, unsigned long size)
 492{
 493}
 494#else
 495extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 496                           unsigned long pfn, unsigned long addr,
 497                           unsigned long size);
 498extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 499                            unsigned long pfn);
 500extern int track_pfn_copy(struct vm_area_struct *vma);
 501extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 502                        unsigned long size);
 503#endif
 504
 505#ifdef __HAVE_COLOR_ZERO_PAGE
 506static inline int is_zero_pfn(unsigned long pfn)
 507{
 508        extern unsigned long zero_pfn;
 509        unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 510        return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 511}
 512
 513#define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 514
 515#else
 516static inline int is_zero_pfn(unsigned long pfn)
 517{
 518        extern unsigned long zero_pfn;
 519        return pfn == zero_pfn;
 520}
 521
 522static inline unsigned long my_zero_pfn(unsigned long addr)
 523{
 524        extern unsigned long zero_pfn;
 525        return zero_pfn;
 526}
 527#endif
 528
 529#ifdef CONFIG_MMU
 530
 531#ifndef CONFIG_TRANSPARENT_HUGEPAGE
 532static inline int pmd_trans_huge(pmd_t pmd)
 533{
 534        return 0;
 535}
 536static inline int pmd_trans_splitting(pmd_t pmd)
 537{
 538        return 0;
 539}
 540#ifndef __HAVE_ARCH_PMD_WRITE
 541static inline int pmd_write(pmd_t pmd)
 542{
 543        BUG();
 544        return 0;
 545}
 546#endif /* __HAVE_ARCH_PMD_WRITE */
 547#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 548
 549#ifndef pmd_read_atomic
 550static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 551{
 552        /*
 553         * Depend on compiler for an atomic pmd read. NOTE: this is
 554         * only going to work, if the pmdval_t isn't larger than
 555         * an unsigned long.
 556         */
 557        return *pmdp;
 558}
 559#endif
 560
 561/*
 562 * This function is meant to be used by sites walking pagetables with
 563 * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 564 * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 565 * into a null pmd and the transhuge page fault can convert a null pmd
 566 * into an hugepmd or into a regular pmd (if the hugepage allocation
 567 * fails). While holding the mmap_sem in read mode the pmd becomes
 568 * stable and stops changing under us only if it's not null and not a
 569 * transhuge pmd. When those races occurs and this function makes a
 570 * difference vs the standard pmd_none_or_clear_bad, the result is
 571 * undefined so behaving like if the pmd was none is safe (because it
 572 * can return none anyway). The compiler level barrier() is critically
 573 * important to compute the two checks atomically on the same pmdval.
 574 *
 575 * For 32bit kernels with a 64bit large pmd_t this automatically takes
 576 * care of reading the pmd atomically to avoid SMP race conditions
 577 * against pmd_populate() when the mmap_sem is hold for reading by the
 578 * caller (a special atomic read not done by "gcc" as in the generic
 579 * version above, is also needed when THP is disabled because the page
 580 * fault can populate the pmd from under us).
 581 */
 582static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 583{
 584        pmd_t pmdval = pmd_read_atomic(pmd);
 585        /*
 586         * The barrier will stabilize the pmdval in a register or on
 587         * the stack so that it will stop changing under the code.
 588         *
 589         * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 590         * pmd_read_atomic is allowed to return a not atomic pmdval
 591         * (for example pointing to an hugepage that has never been
 592         * mapped in the pmd). The below checks will only care about
 593         * the low part of the pmd with 32bit PAE x86 anyway, with the
 594         * exception of pmd_none(). So the important thing is that if
 595         * the low part of the pmd is found null, the high part will
 596         * be also null or the pmd_none() check below would be
 597         * confused.
 598         */
 599#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 600        barrier();
 601#endif
 602        if (pmd_none(pmdval))
 603                return 1;
 604        if (unlikely(pmd_bad(pmdval))) {
 605                if (!pmd_trans_huge(pmdval))
 606                        pmd_clear_bad(pmd);
 607                return 1;
 608        }
 609        return 0;
 610}
 611
 612/*
 613 * This is a noop if Transparent Hugepage Support is not built into
 614 * the kernel. Otherwise it is equivalent to
 615 * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 616 * places that already verified the pmd is not none and they want to
 617 * walk ptes while holding the mmap sem in read mode (write mode don't
 618 * need this). If THP is not enabled, the pmd can't go away under the
 619 * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 620 * run a pmd_trans_unstable before walking the ptes after
 621 * split_huge_page_pmd returns (because it may have run when the pmd
 622 * become null, but then a page fault can map in a THP and not a
 623 * regular page).
 624 */
 625static inline int pmd_trans_unstable(pmd_t *pmd)
 626{
 627#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 628        return pmd_none_or_trans_huge_or_clear_bad(pmd);
 629#else
 630        return 0;
 631#endif
 632}
 633
 634#ifdef CONFIG_NUMA_BALANCING
 635#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
 636/*
 637 * _PAGE_NUMA works identical to _PAGE_PROTNONE (it's actually the
 638 * same bit too). It's set only when _PAGE_PRESET is not set and it's
 639 * never set if _PAGE_PRESENT is set.
 640 *
 641 * pte/pmd_present() returns true if pte/pmd_numa returns true. Page
 642 * fault triggers on those regions if pte/pmd_numa returns true
 643 * (because _PAGE_PRESENT is not set).
 644 */
 645#ifndef pte_numa
 646static inline int pte_numa(pte_t pte)
 647{
 648        return (pte_flags(pte) &
 649                (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 650}
 651#endif
 652
 653#ifndef pmd_numa
 654static inline int pmd_numa(pmd_t pmd)
 655{
 656        return (pmd_flags(pmd) &
 657                (_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
 658}
 659#endif
 660
 661/*
 662 * pte/pmd_mknuma sets the _PAGE_ACCESSED bitflag automatically
 663 * because they're called by the NUMA hinting minor page fault. If we
 664 * wouldn't set the _PAGE_ACCESSED bitflag here, the TLB miss handler
 665 * would be forced to set it later while filling the TLB after we
 666 * return to userland. That would trigger a second write to memory
 667 * that we optimize away by setting _PAGE_ACCESSED here.
 668 */
 669#ifndef pte_mknonnuma
 670static inline pte_t pte_mknonnuma(pte_t pte)
 671{
 672        pte = pte_clear_flags(pte, _PAGE_NUMA);
 673        return pte_set_flags(pte, _PAGE_PRESENT|_PAGE_ACCESSED);
 674}
 675#endif
 676
 677#ifndef pmd_mknonnuma
 678static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 679{
 680        pmd = pmd_clear_flags(pmd, _PAGE_NUMA);
 681        return pmd_set_flags(pmd, _PAGE_PRESENT|_PAGE_ACCESSED);
 682}
 683#endif
 684
 685#ifndef pte_mknuma
 686static inline pte_t pte_mknuma(pte_t pte)
 687{
 688        pte = pte_set_flags(pte, _PAGE_NUMA);
 689        return pte_clear_flags(pte, _PAGE_PRESENT);
 690}
 691#endif
 692
 693#ifndef pmd_mknuma
 694static inline pmd_t pmd_mknuma(pmd_t pmd)
 695{
 696        pmd = pmd_set_flags(pmd, _PAGE_NUMA);
 697        return pmd_clear_flags(pmd, _PAGE_PRESENT);
 698}
 699#endif
 700#else
 701extern int pte_numa(pte_t pte);
 702extern int pmd_numa(pmd_t pmd);
 703extern pte_t pte_mknonnuma(pte_t pte);
 704extern pmd_t pmd_mknonnuma(pmd_t pmd);
 705extern pte_t pte_mknuma(pte_t pte);
 706extern pmd_t pmd_mknuma(pmd_t pmd);
 707#endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */
 708#else
 709static inline int pmd_numa(pmd_t pmd)
 710{
 711        return 0;
 712}
 713
 714static inline int pte_numa(pte_t pte)
 715{
 716        return 0;
 717}
 718
 719static inline pte_t pte_mknonnuma(pte_t pte)
 720{
 721        return pte;
 722}
 723
 724static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 725{
 726        return pmd;
 727}
 728
 729static inline pte_t pte_mknuma(pte_t pte)
 730{
 731        return pte;
 732}
 733
 734static inline pmd_t pmd_mknuma(pmd_t pmd)
 735{
 736        return pmd;
 737}
 738#endif /* CONFIG_NUMA_BALANCING */
 739
 740#endif /* CONFIG_MMU */
 741
 742#endif /* !__ASSEMBLY__ */
 743
 744#ifndef io_remap_pfn_range
 745#define io_remap_pfn_range remap_pfn_range
 746#endif
 747
 748#endif /* _ASM_GENERIC_PGTABLE_H */
 749