include/asm-generic/pgtable.h

   1 #ifndef _ASM_GENERIC_PGTABLE_H
   2 #define _ASM_GENERIC_PGTABLE_H
   3
   4 #include <linux/pfn.h>
   5
   6 #ifndef __ASSEMBLY__
   7 #ifdef CONFIG_MMU
   8
   9 #include <linux/mm_types.h>
  10 #include <linux/bug.h>
  11 #include <linux/errno.h>
  12
  13 #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
  14         defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
  15 #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
  16 #endif
  17
  18 /*
  19  * On almost all architectures and configurations, 0 can be used as the
  20  * upper ceiling to free_pgtables(): on many architectures it has the same
  21  * effect as using TASK_SIZE.  However, there is one configuration which
  22  * must impose a more careful limit, to avoid freeing kernel pgtables.
  23  */
  24 #ifndef USER_PGTABLES_CEILING
  25 #define USER_PGTABLES_CEILING   0UL
  26 #endif
  27
  28 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  29 extern int ptep_set_access_flags(struct vm_area_struct *vma,
  30                                  unsigned long address, pte_t *ptep,
  31                                  pte_t entry, int dirty);
  32 #endif
  33
  34 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  35 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  36 extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  37                                  unsigned long address, pmd_t *pmdp,
  38                                  pmd_t entry, int dirty);
  39 extern int pudp_set_access_flags(struct vm_area_struct *vma,
  40                                  unsigned long address, pud_t *pudp,
  41                                  pud_t entry, int dirty);
  42 #else
  43 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
  44                                         unsigned long address, pmd_t *pmdp,
  45                                         pmd_t entry, int dirty)
  46 {
  47         BUILD_BUG();
  48         return 0;
  49 }
  50 static inline int pudp_set_access_flags(struct vm_area_struct *vma,
  51                                         unsigned long address, pud_t *pudp,
  52                                         pud_t entry, int dirty)
  53 {
  54         BUILD_BUG();
  55         return 0;
  56 }
  57 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  58 #endif
  59
  60 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  61 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
  62                                             unsigned long address,
  63                                             pte_t *ptep)
  64 {
  65         pte_t pte = *ptep;
  66         int r = 1;
  67         if (!pte_young(pte))
  68                 r = 0;
  69         else
  70                 set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
  71         return r;
  72 }
  73 #endif
  74
  75 #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
  76 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  77 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  78                                             unsigned long address,
  79                                             pmd_t *pmdp)
  80 {
  81         pmd_t pmd = *pmdp;
  82         int r = 1;
  83         if (!pmd_young(pmd))
  84                 r = 0;
  85         else
  86                 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
  87         return r;
  88 }
  89 #else
  90 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  91                                             unsigned long address,
  92                                             pmd_t *pmdp)
  93 {
  94         BUILD_BUG();
  95         return 0;
  96 }
  97 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  98 #endif
  99
 100 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 101 int ptep_clear_flush_young(struct vm_area_struct *vma,
 102                            unsigned long address, pte_t *ptep);
 103 #endif
 104
 105 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 106 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 107 extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 108                                   unsigned long address, pmd_t *pmdp);
 109 #else
 110 /*
 111  * Despite relevant to THP only, this API is called from generic rmap code
 112  * under PageTransHuge(), hence needs a dummy implementation for !THP
 113  */
 114 static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
 115                                          unsigned long address, pmd_t *pmdp)
 116 {
 117         BUILD_BUG();
 118         return 0;
 119 }
 120 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 121 #endif
 122
 123 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 124 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 125                                        unsigned long address,
 126                                        pte_t *ptep)
 127 {
 128         pte_t pte = *ptep;
 129         pte_clear(mm, address, ptep);
 130         return pte;
 131 }
 132 #endif
 133
 134 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 135 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
 136 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 137                                             unsigned long address,
 138                                             pmd_t *pmdp)
 139 {
 140         pmd_t pmd = *pmdp;
 141         pmd_clear(pmdp);
 142         return pmd;
 143 }
 144 #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
 145 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
 146 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
 147                                             unsigned long address,
 148                                             pud_t *pudp)
 149 {
 150         pud_t pud = *pudp;
 151
 152         pud_clear(pudp);
 153         return pud;
 154 }
 155 #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
 156 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 157
 158 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 159 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
 160 static inline pmd_t pmdp_huge_get_and_clear_full(struct mm_struct *mm,
 161                                             unsigned long address, pmd_t *pmdp,
 162                                             int full)
 163 {
 164         return pmdp_huge_get_and_clear(mm, address, pmdp);
 165 }
 166 #endif
 167
 168 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
 169 static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
 170                                             unsigned long address, pud_t *pudp,
 171                                             int full)
 172 {
 173         return pudp_huge_get_and_clear(mm, address, pudp);
 174 }
 175 #endif
 176 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 177
 178 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 179 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 180                                             unsigned long address, pte_t *ptep,
 181                                             int full)
 182 {
 183         pte_t pte;
 184         pte = ptep_get_and_clear(mm, address, ptep);
 185         return pte;
 186 }
 187 #endif
 188
 189 /*
 190  * Some architectures may be able to avoid expensive synchronization
 191  * primitives when modifications are made to PTE's which are already
 192  * not present, or in the process of an address space destruction.
 193  */
 194 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 195 static inline void pte_clear_not_present_full(struct mm_struct *mm,
 196                                               unsigned long address,
 197                                               pte_t *ptep,
 198                                               int full)
 199 {
 200         pte_clear(mm, address, ptep);
 201 }
 202 #endif
 203
 204 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 205 extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
 206                               unsigned long address,
 207                               pte_t *ptep);
 208 #endif
 209
 210 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 211 extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
 212                               unsigned long address,
 213                               pmd_t *pmdp);
 214 extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
 215                               unsigned long address,
 216                               pud_t *pudp);
 217 #endif
 218
 219 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 220 struct mm_struct;
 221 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 222 {
 223         pte_t old_pte = *ptep;
 224         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 225 }
 226 #endif
 227
 228 #ifndef pte_savedwrite
 229 #define pte_savedwrite pte_write
 230 #endif
 231
 232 #ifndef pte_mk_savedwrite
 233 #define pte_mk_savedwrite pte_mkwrite
 234 #endif
 235
 236 #ifndef pte_clear_savedwrite
 237 #define pte_clear_savedwrite pte_wrprotect
 238 #endif
 239
 240 #ifndef pmd_savedwrite
 241 #define pmd_savedwrite pmd_write
 242 #endif
 243
 244 #ifndef pmd_mk_savedwrite
 245 #define pmd_mk_savedwrite pmd_mkwrite
 246 #endif
 247
 248 #ifndef pmd_clear_savedwrite
 249 #define pmd_clear_savedwrite pmd_wrprotect
 250 #endif
 251
 252 #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
 253 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 254 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 255                                       unsigned long address, pmd_t *pmdp)
 256 {
 257         pmd_t old_pmd = *pmdp;
 258         set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 259 }
 260 #else
 261 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 262                                       unsigned long address, pmd_t *pmdp)
 263 {
 264         BUILD_BUG();
 265 }
 266 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 267 #endif
 268 #ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
 269 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 270 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 271                                       unsigned long address, pud_t *pudp)
 272 {
 273         pud_t old_pud = *pudp;
 274
 275         set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
 276 }
 277 #else
 278 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 279                                       unsigned long address, pud_t *pudp)
 280 {
 281         BUILD_BUG();
 282 }
 283 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 284 #endif
 285
 286 #ifndef pmdp_collapse_flush
 287 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 288 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 289                                  unsigned long address, pmd_t *pmdp);
 290 #else
 291 static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 292                                         unsigned long address,
 293                                         pmd_t *pmdp)
 294 {
 295         BUILD_BUG();
 296         return *pmdp;
 297 }
 298 #define pmdp_collapse_flush pmdp_collapse_flush
 299 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 300 #endif
 301
 302 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 303 extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 304                                        pgtable_t pgtable);
 305 #endif
 306
 307 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 308 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 309 #endif
 310
 311 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 312 extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 313                             pmd_t *pmdp);
 314 #endif
 315
 316 #ifndef __HAVE_ARCH_PMDP_HUGE_SPLIT_PREPARE
 317 static inline void pmdp_huge_split_prepare(struct vm_area_struct *vma,
 318                                            unsigned long address, pmd_t *pmdp)
 319 {
 320
 321 }
 322 #endif
 323
 324 #ifndef __HAVE_ARCH_PTE_SAME
 325 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 326 {
 327         return pte_val(pte_a) == pte_val(pte_b);
 328 }
 329 #endif
 330
 331 #ifndef __HAVE_ARCH_PTE_UNUSED
 332 /*
 333  * Some architectures provide facilities to virtualization guests
 334  * so that they can flag allocated pages as unused. This allows the
 335  * host to transparently reclaim unused pages. This function returns
 336  * whether the pte's page is unused.
 337  */
 338 static inline int pte_unused(pte_t pte)
 339 {
 340         return 0;
 341 }
 342 #endif
 343
 344 #ifndef pte_access_permitted
 345 #define pte_access_permitted(pte, write) \
 346         (pte_present(pte) && (!(write) || pte_write(pte)))
 347 #endif
 348
 349 #ifndef pmd_access_permitted
 350 #define pmd_access_permitted(pmd, write) \
 351         (pmd_present(pmd) && (!(write) || pmd_write(pmd)))
 352 #endif
 353
 354 #ifndef pud_access_permitted
 355 #define pud_access_permitted(pud, write) \
 356         (pud_present(pud) && (!(write) || pud_write(pud)))
 357 #endif
 358
 359 #ifndef p4d_access_permitted
 360 #define p4d_access_permitted(p4d, write) \
 361         (p4d_present(p4d) && (!(write) || p4d_write(p4d)))
 362 #endif
 363
 364 #ifndef pgd_access_permitted
 365 #define pgd_access_permitted(pgd, write) \
 366         (pgd_present(pgd) && (!(write) || pgd_write(pgd)))
 367 #endif
 368
 369 #ifndef __HAVE_ARCH_PMD_SAME
 370 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 371 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 372 {
 373         return pmd_val(pmd_a) == pmd_val(pmd_b);
 374 }
 375
 376 static inline int pud_same(pud_t pud_a, pud_t pud_b)
 377 {
 378         return pud_val(pud_a) == pud_val(pud_b);
 379 }
 380 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 381 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 382 {
 383         BUILD_BUG();
 384         return 0;
 385 }
 386
 387 static inline int pud_same(pud_t pud_a, pud_t pud_b)
 388 {
 389         BUILD_BUG();
 390         return 0;
 391 }
 392 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 393 #endif
 394
 395 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 396 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 397 #endif
 398
 399 #ifndef __HAVE_ARCH_MOVE_PTE
 400 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 401 #endif
 402
 403 #ifndef pte_accessible
 404 # define pte_accessible(mm, pte)        ((void)(pte), 1)
 405 #endif
 406
 407 #ifndef flush_tlb_fix_spurious_fault
 408 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 409 #endif
 410
 411 #ifndef pgprot_noncached
 412 #define pgprot_noncached(prot)  (prot)
 413 #endif
 414
 415 #ifndef pgprot_writecombine
 416 #define pgprot_writecombine pgprot_noncached
 417 #endif
 418
 419 #ifndef pgprot_writethrough
 420 #define pgprot_writethrough pgprot_noncached
 421 #endif
 422
 423 #ifndef pgprot_device
 424 #define pgprot_device pgprot_noncached
 425 #endif
 426
 427 #ifndef pgprot_modify
 428 #define pgprot_modify pgprot_modify
 429 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 430 {
 431         if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
 432                 newprot = pgprot_noncached(newprot);
 433         if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
 434                 newprot = pgprot_writecombine(newprot);
 435         if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
 436                 newprot = pgprot_device(newprot);
 437         return newprot;
 438 }
 439 #endif
 440
 441 /*
 442  * When walking page tables, get the address of the next boundary,
 443  * or the end address of the range if that comes earlier.  Although no
 444  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 445  */
 446
 447 #define pgd_addr_end(addr, end)                                         \
 448 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 449         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 450 })
 451
 452 #ifndef p4d_addr_end
 453 #define p4d_addr_end(addr, end)                                         \
 454 ({      unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;      \
 455         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 456 })
 457 #endif
 458
 459 #ifndef pud_addr_end
 460 #define pud_addr_end(addr, end)                                         \
 461 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 462         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 463 })
 464 #endif
 465
 466 #ifndef pmd_addr_end
 467 #define pmd_addr_end(addr, end)                                         \
 468 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 469         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 470 })
 471 #endif
 472
 473 /*
 474  * When walking page tables, we usually want to skip any p?d_none entries;
 475  * and any p?d_bad entries - reporting the error before resetting to none.
 476  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 477  */
 478 void pgd_clear_bad(pgd_t *);
 479 void p4d_clear_bad(p4d_t *);
 480 void pud_clear_bad(pud_t *);
 481 void pmd_clear_bad(pmd_t *);
 482
 483 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 484 {
 485         if (pgd_none(*pgd))
 486                 return 1;
 487         if (unlikely(pgd_bad(*pgd))) {
 488                 pgd_clear_bad(pgd);
 489                 return 1;
 490         }
 491         return 0;
 492 }
 493
 494 static inline int p4d_none_or_clear_bad(p4d_t *p4d)
 495 {
 496         if (p4d_none(*p4d))
 497                 return 1;
 498         if (unlikely(p4d_bad(*p4d))) {
 499                 p4d_clear_bad(p4d);
 500                 return 1;
 501         }
 502         return 0;
 503 }
 504
 505 static inline int pud_none_or_clear_bad(pud_t *pud)
 506 {
 507         if (pud_none(*pud))
 508                 return 1;
 509         if (unlikely(pud_bad(*pud))) {
 510                 pud_clear_bad(pud);
 511                 return 1;
 512         }
 513         return 0;
 514 }
 515
 516 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 517 {
 518         if (pmd_none(*pmd))
 519                 return 1;
 520         if (unlikely(pmd_bad(*pmd))) {
 521                 pmd_clear_bad(pmd);
 522                 return 1;
 523         }
 524         return 0;
 525 }
 526
 527 static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
 528                                              unsigned long addr,
 529                                              pte_t *ptep)
 530 {
 531         /*
 532          * Get the current pte state, but zero it out to make it
 533          * non-present, preventing the hardware from asynchronously
 534          * updating it.
 535          */
 536         return ptep_get_and_clear(mm, addr, ptep);
 537 }
 538
 539 static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
 540                                              unsigned long addr,
 541                                              pte_t *ptep, pte_t pte)
 542 {
 543         /*
 544          * The pte is non-present, so there's no hardware state to
 545          * preserve.
 546          */
 547         set_pte_at(mm, addr, ptep, pte);
 548 }
 549
 550 #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 551 /*
 552  * Start a pte protection read-modify-write transaction, which
 553  * protects against asynchronous hardware modifications to the pte.
 554  * The intention is not to prevent the hardware from making pte
 555  * updates, but to prevent any updates it may make from being lost.
 556  *
 557  * This does not protect against other software modifications of the
 558  * pte; the appropriate pte lock must be held over the transation.
 559  *
 560  * Note that this interface is intended to be batchable, meaning that
 561  * ptep_modify_prot_commit may not actually update the pte, but merely
 562  * queue the update to be done at some later time.  The update must be
 563  * actually committed before the pte lock is released, however.
 564  */
 565 static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
 566                                            unsigned long addr,
 567                                            pte_t *ptep)
 568 {
 569         return __ptep_modify_prot_start(mm, addr, ptep);
 570 }
 571
 572 /*
 573  * Commit an update to a pte, leaving any hardware-controlled bits in
 574  * the PTE unmodified.
 575  */
 576 static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 577                                            unsigned long addr,
 578                                            pte_t *ptep, pte_t pte)
 579 {
 580         __ptep_modify_prot_commit(mm, addr, ptep, pte);
 581 }
 582 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 583 #endif /* CONFIG_MMU */
 584
 585 /*
 586  * A facility to provide lazy MMU batching.  This allows PTE updates and
 587  * page invalidations to be delayed until a call to leave lazy MMU mode
 588  * is issued.  Some architectures may benefit from doing this, and it is
 589  * beneficial for both shadow and direct mode hypervisors, which may batch
 590  * the PTE updates which happen during this window.  Note that using this
 591  * interface requires that read hazards be removed from the code.  A read
 592  * hazard could result in the direct mode hypervisor case, since the actual
 593  * write to the page tables may not yet have taken place, so reads though
 594  * a raw PTE pointer after it has been modified are not guaranteed to be
 595  * up to date.  This mode can only be entered and left under the protection of
 596  * the page table locks for all page tables which may be modified.  In the UP
 597  * case, this is required so that preemption is disabled, and in the SMP case,
 598  * it must synchronize the delayed page table writes properly on other CPUs.
 599  */
 600 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 601 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 602 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 603 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 604 #endif
 605
 606 /*
 607  * A facility to provide batching of the reload of page tables and
 608  * other process state with the actual context switch code for
 609  * paravirtualized guests.  By convention, only one of the batched
 610  * update (lazy) modes (CPU, MMU) should be active at any given time,
 611  * entry should never be nested, and entry and exits should always be
 612  * paired.  This is for sanity of maintaining and reasoning about the
 613  * kernel code.  In this case, the exit (end of the context switch) is
 614  * in architecture-specific code, and so doesn't need a generic
 615  * definition.
 616  */
 617 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 618 #define arch_start_context_switch(prev) do {} while (0)
 619 #endif
 620
 621 #ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
 622 static inline int pte_soft_dirty(pte_t pte)
 623 {
 624         return 0;
 625 }
 626
 627 static inline int pmd_soft_dirty(pmd_t pmd)
 628 {
 629         return 0;
 630 }
 631
 632 static inline pte_t pte_mksoft_dirty(pte_t pte)
 633 {
 634         return pte;
 635 }
 636
 637 static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 638 {
 639         return pmd;
 640 }
 641
 642 static inline pte_t pte_clear_soft_dirty(pte_t pte)
 643 {
 644         return pte;
 645 }
 646
 647 static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
 648 {
 649         return pmd;
 650 }
 651
 652 static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 653 {
 654         return pte;
 655 }
 656
 657 static inline int pte_swp_soft_dirty(pte_t pte)
 658 {
 659         return 0;
 660 }
 661
 662 static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 663 {
 664         return pte;
 665 }
 666 #endif
 667
 668 #ifndef __HAVE_PFNMAP_TRACKING
 669 /*
 670  * Interfaces that can be used by architecture code to keep track of
 671  * memory type of pfn mappings specified by the remap_pfn_range,
 672  * vm_insert_pfn.
 673  */
 674
 675 /*
 676  * track_pfn_remap is called when a _new_ pfn mapping is being established
 677  * by remap_pfn_range() for physical range indicated by pfn and size.
 678  */
 679 static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 680                                   unsigned long pfn, unsigned long addr,
 681                                   unsigned long size)
 682 {
 683         return 0;
 684 }
 685
 686 /*
 687  * track_pfn_insert is called when a _new_ single pfn is established
 688  * by vm_insert_pfn().
 689  */
 690 static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 691                                     pfn_t pfn)
 692 {
 693 }
 694
 695 /*
 696  * track_pfn_copy is called when vma that is covering the pfnmap gets
 697  * copied through copy_page_range().
 698  */
 699 static inline int track_pfn_copy(struct vm_area_struct *vma)
 700 {
 701         return 0;
 702 }
 703
 704 /*
 705  * untrack_pfn is called while unmapping a pfnmap for a region.
 706  * untrack can be called for a specific region indicated by pfn and size or
 707  * can be for the entire vma (in which case pfn, size are zero).
 708  */
 709 static inline void untrack_pfn(struct vm_area_struct *vma,
 710                                unsigned long pfn, unsigned long size)
 711 {
 712 }
 713
 714 /*
 715  * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
 716  */
 717 static inline void untrack_pfn_moved(struct vm_area_struct *vma)
 718 {
 719 }
 720 #else
 721 extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 722                            unsigned long pfn, unsigned long addr,
 723                            unsigned long size);
 724 extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 725                              pfn_t pfn);
 726 extern int track_pfn_copy(struct vm_area_struct *vma);
 727 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 728                         unsigned long size);
 729 extern void untrack_pfn_moved(struct vm_area_struct *vma);
 730 #endif
 731
 732 #ifdef __HAVE_COLOR_ZERO_PAGE
 733 static inline int is_zero_pfn(unsigned long pfn)
 734 {
 735         extern unsigned long zero_pfn;
 736         unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 737         return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 738 }
 739
 740 #define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 741
 742 #else
 743 static inline int is_zero_pfn(unsigned long pfn)
 744 {
 745         extern unsigned long zero_pfn;
 746         return pfn == zero_pfn;
 747 }
 748
 749 static inline unsigned long my_zero_pfn(unsigned long addr)
 750 {
 751         extern unsigned long zero_pfn;
 752         return zero_pfn;
 753 }
 754 #endif
 755
 756 #ifdef CONFIG_MMU
 757
 758 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 759 static inline int pmd_trans_huge(pmd_t pmd)
 760 {
 761         return 0;
 762 }
 763 #ifndef __HAVE_ARCH_PMD_WRITE
 764 static inline int pmd_write(pmd_t pmd)
 765 {
 766         BUG();
 767         return 0;
 768 }
 769 #endif /* __HAVE_ARCH_PMD_WRITE */
 770 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 771
 772 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 773         (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 774          !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 775 static inline int pud_trans_huge(pud_t pud)
 776 {
 777         return 0;
 778 }
 779 #endif
 780
 781 #ifndef pmd_read_atomic
 782 static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 783 {
 784         /*
 785          * Depend on compiler for an atomic pmd read. NOTE: this is
 786          * only going to work, if the pmdval_t isn't larger than
 787          * an unsigned long.
 788          */
 789         return *pmdp;
 790 }
 791 #endif
 792
 793 #ifndef arch_needs_pgtable_deposit
 794 #define arch_needs_pgtable_deposit() (false)
 795 #endif
 796 /*
 797  * This function is meant to be used by sites walking pagetables with
 798  * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 799  * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 800  * into a null pmd and the transhuge page fault can convert a null pmd
 801  * into an hugepmd or into a regular pmd (if the hugepage allocation
 802  * fails). While holding the mmap_sem in read mode the pmd becomes
 803  * stable and stops changing under us only if it's not null and not a
 804  * transhuge pmd. When those races occurs and this function makes a
 805  * difference vs the standard pmd_none_or_clear_bad, the result is
 806  * undefined so behaving like if the pmd was none is safe (because it
 807  * can return none anyway). The compiler level barrier() is critically
 808  * important to compute the two checks atomically on the same pmdval.
 809  *
 810  * For 32bit kernels with a 64bit large pmd_t this automatically takes
 811  * care of reading the pmd atomically to avoid SMP race conditions
 812  * against pmd_populate() when the mmap_sem is hold for reading by the
 813  * caller (a special atomic read not done by "gcc" as in the generic
 814  * version above, is also needed when THP is disabled because the page
 815  * fault can populate the pmd from under us).
 816  */
 817 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 818 {
 819         pmd_t pmdval = pmd_read_atomic(pmd);
 820         /*
 821          * The barrier will stabilize the pmdval in a register or on
 822          * the stack so that it will stop changing under the code.
 823          *
 824          * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 825          * pmd_read_atomic is allowed to return a not atomic pmdval
 826          * (for example pointing to an hugepage that has never been
 827          * mapped in the pmd). The below checks will only care about
 828          * the low part of the pmd with 32bit PAE x86 anyway, with the
 829          * exception of pmd_none(). So the important thing is that if
 830          * the low part of the pmd is found null, the high part will
 831          * be also null or the pmd_none() check below would be
 832          * confused.
 833          */
 834 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 835         barrier();
 836 #endif
 837         if (pmd_none(pmdval) || pmd_trans_huge(pmdval))
 838                 return 1;
 839         if (unlikely(pmd_bad(pmdval))) {
 840                 pmd_clear_bad(pmd);
 841                 return 1;
 842         }
 843         return 0;
 844 }
 845
 846 /*
 847  * This is a noop if Transparent Hugepage Support is not built into
 848  * the kernel. Otherwise it is equivalent to
 849  * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 850  * places that already verified the pmd is not none and they want to
 851  * walk ptes while holding the mmap sem in read mode (write mode don't
 852  * need this). If THP is not enabled, the pmd can't go away under the
 853  * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 854  * run a pmd_trans_unstable before walking the ptes after
 855  * split_huge_page_pmd returns (because it may have run when the pmd
 856  * become null, but then a page fault can map in a THP and not a
 857  * regular page).
 858  */
 859 static inline int pmd_trans_unstable(pmd_t *pmd)
 860 {
 861 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 862         return pmd_none_or_trans_huge_or_clear_bad(pmd);
 863 #else
 864         return 0;
 865 #endif
 866 }
 867
 868 #ifndef CONFIG_NUMA_BALANCING
 869 /*
 870  * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
 871  * the only case the kernel cares is for NUMA balancing and is only ever set
 872  * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
 873  * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
 874  * is the responsibility of the caller to distinguish between PROT_NONE
 875  * protections and NUMA hinting fault protections.
 876  */
 877 static inline int pte_protnone(pte_t pte)
 878 {
 879         return 0;
 880 }
 881
 882 static inline int pmd_protnone(pmd_t pmd)
 883 {
 884         return 0;
 885 }
 886 #endif /* CONFIG_NUMA_BALANCING */
 887
 888 #endif /* CONFIG_MMU */
 889
 890 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 891
 892 #ifndef __PAGETABLE_P4D_FOLDED
 893 int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
 894 int p4d_clear_huge(p4d_t *p4d);
 895 #else
 896 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
 897 {
 898         return 0;
 899 }
 900 static inline int p4d_clear_huge(p4d_t *p4d)
 901 {
 902         return 0;
 903 }
 904 #endif /* !__PAGETABLE_P4D_FOLDED */
 905
 906 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
 907 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
 908 int pud_clear_huge(pud_t *pud);
 909 int pmd_clear_huge(pmd_t *pmd);
 910 #else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 911 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
 912 {
 913         return 0;
 914 }
 915 static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 916 {
 917         return 0;
 918 }
 919 static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
 920 {
 921         return 0;
 922 }
 923 static inline int p4d_clear_huge(p4d_t *p4d)
 924 {
 925         return 0;
 926 }
 927 static inline int pud_clear_huge(pud_t *pud)
 928 {
 929         return 0;
 930 }
 931 static inline int pmd_clear_huge(pmd_t *pmd)
 932 {
 933         return 0;
 934 }
 935 #endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 936
 937 #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
 938 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 939 /*
 940  * ARCHes with special requirements for evicting THP backing TLB entries can
 941  * implement this. Otherwise also, it can help optimize normal TLB flush in
 942  * THP regime. stock flush_tlb_range() typically has optimization to nuke the
 943  * entire TLB TLB if flush span is greater than a threshold, which will
 944  * likely be true for a single huge page. Thus a single thp flush will
 945  * invalidate the entire TLB which is not desitable.
 946  * e.g. see arch/arc: flush_pmd_tlb_range
 947  */
 948 #define flush_pmd_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
 949 #define flush_pud_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
 950 #else
 951 #define flush_pmd_tlb_range(vma, addr, end)     BUILD_BUG()
 952 #define flush_pud_tlb_range(vma, addr, end)     BUILD_BUG()
 953 #endif
 954 #endif
 955
 956 struct file;
 957 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 958                         unsigned long size, pgprot_t *vma_prot);
 959 #endif /* !__ASSEMBLY__ */
 960
 961 #ifndef io_remap_pfn_range
 962 #define io_remap_pfn_range remap_pfn_range
 963 #endif
 964
 965 #ifndef has_transparent_hugepage
 966 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 967 #define has_transparent_hugepage() 1
 968 #else
 969 #define has_transparent_hugepage() 0
 970 #endif
 971 #endif
 972
 973 #endif /* _ASM_GENERIC_PGTABLE_H */