include/asm-generic/pgtable.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_GENERIC_PGTABLE_H
   3 #define _ASM_GENERIC_PGTABLE_H
   4
   5 #include <linux/pfn.h>
   6
   7 #ifndef __ASSEMBLY__
   8 #ifdef CONFIG_MMU
   9
  10 #include <linux/mm_types.h>
  11 #include <linux/bug.h>
  12 #include <linux/errno.h>
  13
  14 #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
  15         defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
  16 #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
  17 #endif
  18
  19 /*
  20  * On almost all architectures and configurations, 0 can be used as the
  21  * upper ceiling to free_pgtables(): on many architectures it has the same
  22  * effect as using TASK_SIZE.  However, there is one configuration which
  23  * must impose a more careful limit, to avoid freeing kernel pgtables.
  24  */
  25 #ifndef USER_PGTABLES_CEILING
  26 #define USER_PGTABLES_CEILING   0UL
  27 #endif
  28
  29 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  30 extern int ptep_set_access_flags(struct vm_area_struct *vma,
  31                                  unsigned long address, pte_t *ptep,
  32                                  pte_t entry, int dirty);
  33 #endif
  34
  35 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  36 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  37 extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  38                                  unsigned long address, pmd_t *pmdp,
  39                                  pmd_t entry, int dirty);
  40 extern int pudp_set_access_flags(struct vm_area_struct *vma,
  41                                  unsigned long address, pud_t *pudp,
  42                                  pud_t entry, int dirty);
  43 #else
  44 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
  45                                         unsigned long address, pmd_t *pmdp,
  46                                         pmd_t entry, int dirty)
  47 {
  48         BUILD_BUG();
  49         return 0;
  50 }
  51 static inline int pudp_set_access_flags(struct vm_area_struct *vma,
  52                                         unsigned long address, pud_t *pudp,
  53                                         pud_t entry, int dirty)
  54 {
  55         BUILD_BUG();
  56         return 0;
  57 }
  58 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  59 #endif
  60
  61 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  62 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
  63                                             unsigned long address,
  64                                             pte_t *ptep)
  65 {
  66         pte_t pte = *ptep;
  67         int r = 1;
  68         if (!pte_young(pte))
  69                 r = 0;
  70         else
  71                 set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
  72         return r;
  73 }
  74 #endif
  75
  76 #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
  77 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  78 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  79                                             unsigned long address,
  80                                             pmd_t *pmdp)
  81 {
  82         pmd_t pmd = *pmdp;
  83         int r = 1;
  84         if (!pmd_young(pmd))
  85                 r = 0;
  86         else
  87                 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
  88         return r;
  89 }
  90 #else
  91 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  92                                             unsigned long address,
  93                                             pmd_t *pmdp)
  94 {
  95         BUILD_BUG();
  96         return 0;
  97 }
  98 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  99 #endif
 100
 101 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 102 int ptep_clear_flush_young(struct vm_area_struct *vma,
 103                            unsigned long address, pte_t *ptep);
 104 #endif
 105
 106 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 107 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 108 extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 109                                   unsigned long address, pmd_t *pmdp);
 110 #else
 111 /*
 112  * Despite relevant to THP only, this API is called from generic rmap code
 113  * under PageTransHuge(), hence needs a dummy implementation for !THP
 114  */
 115 static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
 116                                          unsigned long address, pmd_t *pmdp)
 117 {
 118         BUILD_BUG();
 119         return 0;
 120 }
 121 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 122 #endif
 123
 124 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 125 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 126                                        unsigned long address,
 127                                        pte_t *ptep)
 128 {
 129         pte_t pte = *ptep;
 130         pte_clear(mm, address, ptep);
 131         return pte;
 132 }
 133 #endif
 134
 135 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 136 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
 137 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 138                                             unsigned long address,
 139                                             pmd_t *pmdp)
 140 {
 141         pmd_t pmd = *pmdp;
 142         pmd_clear(pmdp);
 143         return pmd;
 144 }
 145 #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
 146 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
 147 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
 148                                             unsigned long address,
 149                                             pud_t *pudp)
 150 {
 151         pud_t pud = *pudp;
 152
 153         pud_clear(pudp);
 154         return pud;
 155 }
 156 #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
 157 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 158
 159 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 160 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
 161 static inline pmd_t pmdp_huge_get_and_clear_full(struct mm_struct *mm,
 162                                             unsigned long address, pmd_t *pmdp,
 163                                             int full)
 164 {
 165         return pmdp_huge_get_and_clear(mm, address, pmdp);
 166 }
 167 #endif
 168
 169 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
 170 static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
 171                                             unsigned long address, pud_t *pudp,
 172                                             int full)
 173 {
 174         return pudp_huge_get_and_clear(mm, address, pudp);
 175 }
 176 #endif
 177 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 178
 179 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 180 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 181                                             unsigned long address, pte_t *ptep,
 182                                             int full)
 183 {
 184         pte_t pte;
 185         pte = ptep_get_and_clear(mm, address, ptep);
 186         return pte;
 187 }
 188 #endif
 189
 190 /*
 191  * Some architectures may be able to avoid expensive synchronization
 192  * primitives when modifications are made to PTE's which are already
 193  * not present, or in the process of an address space destruction.
 194  */
 195 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 196 static inline void pte_clear_not_present_full(struct mm_struct *mm,
 197                                               unsigned long address,
 198                                               pte_t *ptep,
 199                                               int full)
 200 {
 201         pte_clear(mm, address, ptep);
 202 }
 203 #endif
 204
 205 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 206 extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
 207                               unsigned long address,
 208                               pte_t *ptep);
 209 #endif
 210
 211 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 212 extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
 213                               unsigned long address,
 214                               pmd_t *pmdp);
 215 extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
 216                               unsigned long address,
 217                               pud_t *pudp);
 218 #endif
 219
 220 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 221 struct mm_struct;
 222 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 223 {
 224         pte_t old_pte = *ptep;
 225         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 226 }
 227 #endif
 228
 229 #ifndef pte_savedwrite
 230 #define pte_savedwrite pte_write
 231 #endif
 232
 233 #ifndef pte_mk_savedwrite
 234 #define pte_mk_savedwrite pte_mkwrite
 235 #endif
 236
 237 #ifndef pte_clear_savedwrite
 238 #define pte_clear_savedwrite pte_wrprotect
 239 #endif
 240
 241 #ifndef pmd_savedwrite
 242 #define pmd_savedwrite pmd_write
 243 #endif
 244
 245 #ifndef pmd_mk_savedwrite
 246 #define pmd_mk_savedwrite pmd_mkwrite
 247 #endif
 248
 249 #ifndef pmd_clear_savedwrite
 250 #define pmd_clear_savedwrite pmd_wrprotect
 251 #endif
 252
 253 #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
 254 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 255 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 256                                       unsigned long address, pmd_t *pmdp)
 257 {
 258         pmd_t old_pmd = *pmdp;
 259         set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 260 }
 261 #else
 262 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 263                                       unsigned long address, pmd_t *pmdp)
 264 {
 265         BUILD_BUG();
 266 }
 267 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 268 #endif
 269 #ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
 270 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 271 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 272                                       unsigned long address, pud_t *pudp)
 273 {
 274         pud_t old_pud = *pudp;
 275
 276         set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
 277 }
 278 #else
 279 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 280                                       unsigned long address, pud_t *pudp)
 281 {
 282         BUILD_BUG();
 283 }
 284 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 285 #endif
 286
 287 #ifndef pmdp_collapse_flush
 288 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 289 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 290                                  unsigned long address, pmd_t *pmdp);
 291 #else
 292 static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 293                                         unsigned long address,
 294                                         pmd_t *pmdp)
 295 {
 296         BUILD_BUG();
 297         return *pmdp;
 298 }
 299 #define pmdp_collapse_flush pmdp_collapse_flush
 300 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 301 #endif
 302
 303 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 304 extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 305                                        pgtable_t pgtable);
 306 #endif
 307
 308 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 309 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 310 #endif
 311
 312 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 313 /*
 314  * This is an implementation of pmdp_establish() that is only suitable for an
 315  * architecture that doesn't have hardware dirty/accessed bits. In this case we
 316  * can't race with CPU which sets these bits and non-atomic aproach is fine.
 317  */
 318 static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
 319                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
 320 {
 321         pmd_t old_pmd = *pmdp;
 322         set_pmd_at(vma->vm_mm, address, pmdp, pmd);
 323         return old_pmd;
 324 }
 325 #endif
 326
 327 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 328 extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 329                             pmd_t *pmdp);
 330 #endif
 331
 332 #ifndef __HAVE_ARCH_PTE_SAME
 333 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 334 {
 335         return pte_val(pte_a) == pte_val(pte_b);
 336 }
 337 #endif
 338
 339 #ifndef __HAVE_ARCH_PTE_UNUSED
 340 /*
 341  * Some architectures provide facilities to virtualization guests
 342  * so that they can flag allocated pages as unused. This allows the
 343  * host to transparently reclaim unused pages. This function returns
 344  * whether the pte's page is unused.
 345  */
 346 static inline int pte_unused(pte_t pte)
 347 {
 348         return 0;
 349 }
 350 #endif
 351
 352 #ifndef pte_access_permitted
 353 #define pte_access_permitted(pte, write) \
 354         (pte_present(pte) && (!(write) || pte_write(pte)))
 355 #endif
 356
 357 #ifndef pmd_access_permitted
 358 #define pmd_access_permitted(pmd, write) \
 359         (pmd_present(pmd) && (!(write) || pmd_write(pmd)))
 360 #endif
 361
 362 #ifndef pud_access_permitted
 363 #define pud_access_permitted(pud, write) \
 364         (pud_present(pud) && (!(write) || pud_write(pud)))
 365 #endif
 366
 367 #ifndef p4d_access_permitted
 368 #define p4d_access_permitted(p4d, write) \
 369         (p4d_present(p4d) && (!(write) || p4d_write(p4d)))
 370 #endif
 371
 372 #ifndef pgd_access_permitted
 373 #define pgd_access_permitted(pgd, write) \
 374         (pgd_present(pgd) && (!(write) || pgd_write(pgd)))
 375 #endif
 376
 377 #ifndef __HAVE_ARCH_PMD_SAME
 378 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 379 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 380 {
 381         return pmd_val(pmd_a) == pmd_val(pmd_b);
 382 }
 383
 384 static inline int pud_same(pud_t pud_a, pud_t pud_b)
 385 {
 386         return pud_val(pud_a) == pud_val(pud_b);
 387 }
 388 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 389 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 390 {
 391         BUILD_BUG();
 392         return 0;
 393 }
 394
 395 static inline int pud_same(pud_t pud_a, pud_t pud_b)
 396 {
 397         BUILD_BUG();
 398         return 0;
 399 }
 400 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 401 #endif
 402
 403 #ifndef __HAVE_ARCH_DO_SWAP_PAGE
 404 /*
 405  * Some architectures support metadata associated with a page. When a
 406  * page is being swapped out, this metadata must be saved so it can be
 407  * restored when the page is swapped back in. SPARC M7 and newer
 408  * processors support an ADI (Application Data Integrity) tag for the
 409  * page as metadata for the page. arch_do_swap_page() can restore this
 410  * metadata when a page is swapped back in.
 411  */
 412 static inline void arch_do_swap_page(struct mm_struct *mm,
 413                                      struct vm_area_struct *vma,
 414                                      unsigned long addr,
 415                                      pte_t pte, pte_t oldpte)
 416 {
 417
 418 }
 419 #endif
 420
 421 #ifndef __HAVE_ARCH_UNMAP_ONE
 422 /*
 423  * Some architectures support metadata associated with a page. When a
 424  * page is being swapped out, this metadata must be saved so it can be
 425  * restored when the page is swapped back in. SPARC M7 and newer
 426  * processors support an ADI (Application Data Integrity) tag for the
 427  * page as metadata for the page. arch_unmap_one() can save this
 428  * metadata on a swap-out of a page.
 429  */
 430 static inline int arch_unmap_one(struct mm_struct *mm,
 431                                   struct vm_area_struct *vma,
 432                                   unsigned long addr,
 433                                   pte_t orig_pte)
 434 {
 435         return 0;
 436 }
 437 #endif
 438
 439 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 440 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 441 #endif
 442
 443 #ifndef __HAVE_ARCH_MOVE_PTE
 444 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 445 #endif
 446
 447 #ifndef pte_accessible
 448 # define pte_accessible(mm, pte)        ((void)(pte), 1)
 449 #endif
 450
 451 #ifndef flush_tlb_fix_spurious_fault
 452 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 453 #endif
 454
 455 #ifndef pgprot_noncached
 456 #define pgprot_noncached(prot)  (prot)
 457 #endif
 458
 459 #ifndef pgprot_writecombine
 460 #define pgprot_writecombine pgprot_noncached
 461 #endif
 462
 463 #ifndef pgprot_writethrough
 464 #define pgprot_writethrough pgprot_noncached
 465 #endif
 466
 467 #ifndef pgprot_device
 468 #define pgprot_device pgprot_noncached
 469 #endif
 470
 471 #ifndef pgprot_modify
 472 #define pgprot_modify pgprot_modify
 473 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 474 {
 475         if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
 476                 newprot = pgprot_noncached(newprot);
 477         if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
 478                 newprot = pgprot_writecombine(newprot);
 479         if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
 480                 newprot = pgprot_device(newprot);
 481         return newprot;
 482 }
 483 #endif
 484
 485 /*
 486  * When walking page tables, get the address of the next boundary,
 487  * or the end address of the range if that comes earlier.  Although no
 488  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 489  */
 490
 491 #define pgd_addr_end(addr, end)                                         \
 492 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 493         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 494 })
 495
 496 #ifndef p4d_addr_end
 497 #define p4d_addr_end(addr, end)                                         \
 498 ({      unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;      \
 499         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 500 })
 501 #endif
 502
 503 #ifndef pud_addr_end
 504 #define pud_addr_end(addr, end)                                         \
 505 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 506         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 507 })
 508 #endif
 509
 510 #ifndef pmd_addr_end
 511 #define pmd_addr_end(addr, end)                                         \
 512 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 513         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 514 })
 515 #endif
 516
 517 /*
 518  * When walking page tables, we usually want to skip any p?d_none entries;
 519  * and any p?d_bad entries - reporting the error before resetting to none.
 520  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 521  */
 522 void pgd_clear_bad(pgd_t *);
 523 void p4d_clear_bad(p4d_t *);
 524 void pud_clear_bad(pud_t *);
 525 void pmd_clear_bad(pmd_t *);
 526
 527 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 528 {
 529         if (pgd_none(*pgd))
 530                 return 1;
 531         if (unlikely(pgd_bad(*pgd))) {
 532                 pgd_clear_bad(pgd);
 533                 return 1;
 534         }
 535         return 0;
 536 }
 537
 538 static inline int p4d_none_or_clear_bad(p4d_t *p4d)
 539 {
 540         if (p4d_none(*p4d))
 541                 return 1;
 542         if (unlikely(p4d_bad(*p4d))) {
 543                 p4d_clear_bad(p4d);
 544                 return 1;
 545         }
 546         return 0;
 547 }
 548
 549 static inline int pud_none_or_clear_bad(pud_t *pud)
 550 {
 551         if (pud_none(*pud))
 552                 return 1;
 553         if (unlikely(pud_bad(*pud))) {
 554                 pud_clear_bad(pud);
 555                 return 1;
 556         }
 557         return 0;
 558 }
 559
 560 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 561 {
 562         if (pmd_none(*pmd))
 563                 return 1;
 564         if (unlikely(pmd_bad(*pmd))) {
 565                 pmd_clear_bad(pmd);
 566                 return 1;
 567         }
 568         return 0;
 569 }
 570
 571 static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
 572                                              unsigned long addr,
 573                                              pte_t *ptep)
 574 {
 575         /*
 576          * Get the current pte state, but zero it out to make it
 577          * non-present, preventing the hardware from asynchronously
 578          * updating it.
 579          */
 580         return ptep_get_and_clear(mm, addr, ptep);
 581 }
 582
 583 static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
 584                                              unsigned long addr,
 585                                              pte_t *ptep, pte_t pte)
 586 {
 587         /*
 588          * The pte is non-present, so there's no hardware state to
 589          * preserve.
 590          */
 591         set_pte_at(mm, addr, ptep, pte);
 592 }
 593
 594 #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 595 /*
 596  * Start a pte protection read-modify-write transaction, which
 597  * protects against asynchronous hardware modifications to the pte.
 598  * The intention is not to prevent the hardware from making pte
 599  * updates, but to prevent any updates it may make from being lost.
 600  *
 601  * This does not protect against other software modifications of the
 602  * pte; the appropriate pte lock must be held over the transation.
 603  *
 604  * Note that this interface is intended to be batchable, meaning that
 605  * ptep_modify_prot_commit may not actually update the pte, but merely
 606  * queue the update to be done at some later time.  The update must be
 607  * actually committed before the pte lock is released, however.
 608  */
 609 static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
 610                                            unsigned long addr,
 611                                            pte_t *ptep)
 612 {
 613         return __ptep_modify_prot_start(mm, addr, ptep);
 614 }
 615
 616 /*
 617  * Commit an update to a pte, leaving any hardware-controlled bits in
 618  * the PTE unmodified.
 619  */
 620 static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 621                                            unsigned long addr,
 622                                            pte_t *ptep, pte_t pte)
 623 {
 624         __ptep_modify_prot_commit(mm, addr, ptep, pte);
 625 }
 626 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 627 #endif /* CONFIG_MMU */
 628
 629 /*
 630  * No-op macros that just return the current protection value. Defined here
 631  * because these macros can be used used even if CONFIG_MMU is not defined.
 632  */
 633 #ifndef pgprot_encrypted
 634 #define pgprot_encrypted(prot)  (prot)
 635 #endif
 636
 637 #ifndef pgprot_decrypted
 638 #define pgprot_decrypted(prot)  (prot)
 639 #endif
 640
 641 /*
 642  * A facility to provide lazy MMU batching.  This allows PTE updates and
 643  * page invalidations to be delayed until a call to leave lazy MMU mode
 644  * is issued.  Some architectures may benefit from doing this, and it is
 645  * beneficial for both shadow and direct mode hypervisors, which may batch
 646  * the PTE updates which happen during this window.  Note that using this
 647  * interface requires that read hazards be removed from the code.  A read
 648  * hazard could result in the direct mode hypervisor case, since the actual
 649  * write to the page tables may not yet have taken place, so reads though
 650  * a raw PTE pointer after it has been modified are not guaranteed to be
 651  * up to date.  This mode can only be entered and left under the protection of
 652  * the page table locks for all page tables which may be modified.  In the UP
 653  * case, this is required so that preemption is disabled, and in the SMP case,
 654  * it must synchronize the delayed page table writes properly on other CPUs.
 655  */
 656 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 657 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 658 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 659 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 660 #endif
 661
 662 /*
 663  * A facility to provide batching of the reload of page tables and
 664  * other process state with the actual context switch code for
 665  * paravirtualized guests.  By convention, only one of the batched
 666  * update (lazy) modes (CPU, MMU) should be active at any given time,
 667  * entry should never be nested, and entry and exits should always be
 668  * paired.  This is for sanity of maintaining and reasoning about the
 669  * kernel code.  In this case, the exit (end of the context switch) is
 670  * in architecture-specific code, and so doesn't need a generic
 671  * definition.
 672  */
 673 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 674 #define arch_start_context_switch(prev) do {} while (0)
 675 #endif
 676
 677 #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
 678 #ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
 679 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 680 {
 681         return pmd;
 682 }
 683
 684 static inline int pmd_swp_soft_dirty(pmd_t pmd)
 685 {
 686         return 0;
 687 }
 688
 689 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 690 {
 691         return pmd;
 692 }
 693 #endif
 694 #else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
 695 static inline int pte_soft_dirty(pte_t pte)
 696 {
 697         return 0;
 698 }
 699
 700 static inline int pmd_soft_dirty(pmd_t pmd)
 701 {
 702         return 0;
 703 }
 704
 705 static inline pte_t pte_mksoft_dirty(pte_t pte)
 706 {
 707         return pte;
 708 }
 709
 710 static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 711 {
 712         return pmd;
 713 }
 714
 715 static inline pte_t pte_clear_soft_dirty(pte_t pte)
 716 {
 717         return pte;
 718 }
 719
 720 static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
 721 {
 722         return pmd;
 723 }
 724
 725 static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 726 {
 727         return pte;
 728 }
 729
 730 static inline int pte_swp_soft_dirty(pte_t pte)
 731 {
 732         return 0;
 733 }
 734
 735 static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 736 {
 737         return pte;
 738 }
 739
 740 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 741 {
 742         return pmd;
 743 }
 744
 745 static inline int pmd_swp_soft_dirty(pmd_t pmd)
 746 {
 747         return 0;
 748 }
 749
 750 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 751 {
 752         return pmd;
 753 }
 754 #endif
 755
 756 #ifndef __HAVE_PFNMAP_TRACKING
 757 /*
 758  * Interfaces that can be used by architecture code to keep track of
 759  * memory type of pfn mappings specified by the remap_pfn_range,
 760  * vmf_insert_pfn.
 761  */
 762
 763 /*
 764  * track_pfn_remap is called when a _new_ pfn mapping is being established
 765  * by remap_pfn_range() for physical range indicated by pfn and size.
 766  */
 767 static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 768                                   unsigned long pfn, unsigned long addr,
 769                                   unsigned long size)
 770 {
 771         return 0;
 772 }
 773
 774 /*
 775  * track_pfn_insert is called when a _new_ single pfn is established
 776  * by vmf_insert_pfn().
 777  */
 778 static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 779                                     pfn_t pfn)
 780 {
 781 }
 782
 783 /*
 784  * track_pfn_copy is called when vma that is covering the pfnmap gets
 785  * copied through copy_page_range().
 786  */
 787 static inline int track_pfn_copy(struct vm_area_struct *vma)
 788 {
 789         return 0;
 790 }
 791
 792 /*
 793  * untrack_pfn is called while unmapping a pfnmap for a region.
 794  * untrack can be called for a specific region indicated by pfn and size or
 795  * can be for the entire vma (in which case pfn, size are zero).
 796  */
 797 static inline void untrack_pfn(struct vm_area_struct *vma,
 798                                unsigned long pfn, unsigned long size)
 799 {
 800 }
 801
 802 /*
 803  * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
 804  */
 805 static inline void untrack_pfn_moved(struct vm_area_struct *vma)
 806 {
 807 }
 808 #else
 809 extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 810                            unsigned long pfn, unsigned long addr,
 811                            unsigned long size);
 812 extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 813                              pfn_t pfn);
 814 extern int track_pfn_copy(struct vm_area_struct *vma);
 815 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 816                         unsigned long size);
 817 extern void untrack_pfn_moved(struct vm_area_struct *vma);
 818 #endif
 819
 820 #ifdef __HAVE_COLOR_ZERO_PAGE
 821 static inline int is_zero_pfn(unsigned long pfn)
 822 {
 823         extern unsigned long zero_pfn;
 824         unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 825         return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 826 }
 827
 828 #define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 829
 830 #else
 831 static inline int is_zero_pfn(unsigned long pfn)
 832 {
 833         extern unsigned long zero_pfn;
 834         return pfn == zero_pfn;
 835 }
 836
 837 static inline unsigned long my_zero_pfn(unsigned long addr)
 838 {
 839         extern unsigned long zero_pfn;
 840         return zero_pfn;
 841 }
 842 #endif
 843
 844 #ifdef CONFIG_MMU
 845
 846 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 847 static inline int pmd_trans_huge(pmd_t pmd)
 848 {
 849         return 0;
 850 }
 851 #ifndef pmd_write
 852 static inline int pmd_write(pmd_t pmd)
 853 {
 854         BUG();
 855         return 0;
 856 }
 857 #endif /* pmd_write */
 858 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 859
 860 #ifndef pud_write
 861 static inline int pud_write(pud_t pud)
 862 {
 863         BUG();
 864         return 0;
 865 }
 866 #endif /* pud_write */
 867
 868 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 869         (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 870          !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 871 static inline int pud_trans_huge(pud_t pud)
 872 {
 873         return 0;
 874 }
 875 #endif
 876
 877 #ifndef pmd_read_atomic
 878 static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 879 {
 880         /*
 881          * Depend on compiler for an atomic pmd read. NOTE: this is
 882          * only going to work, if the pmdval_t isn't larger than
 883          * an unsigned long.
 884          */
 885         return *pmdp;
 886 }
 887 #endif
 888
 889 #ifndef arch_needs_pgtable_deposit
 890 #define arch_needs_pgtable_deposit() (false)
 891 #endif
 892 /*
 893  * This function is meant to be used by sites walking pagetables with
 894  * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 895  * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 896  * into a null pmd and the transhuge page fault can convert a null pmd
 897  * into an hugepmd or into a regular pmd (if the hugepage allocation
 898  * fails). While holding the mmap_sem in read mode the pmd becomes
 899  * stable and stops changing under us only if it's not null and not a
 900  * transhuge pmd. When those races occurs and this function makes a
 901  * difference vs the standard pmd_none_or_clear_bad, the result is
 902  * undefined so behaving like if the pmd was none is safe (because it
 903  * can return none anyway). The compiler level barrier() is critically
 904  * important to compute the two checks atomically on the same pmdval.
 905  *
 906  * For 32bit kernels with a 64bit large pmd_t this automatically takes
 907  * care of reading the pmd atomically to avoid SMP race conditions
 908  * against pmd_populate() when the mmap_sem is hold for reading by the
 909  * caller (a special atomic read not done by "gcc" as in the generic
 910  * version above, is also needed when THP is disabled because the page
 911  * fault can populate the pmd from under us).
 912  */
 913 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 914 {
 915         pmd_t pmdval = pmd_read_atomic(pmd);
 916         /*
 917          * The barrier will stabilize the pmdval in a register or on
 918          * the stack so that it will stop changing under the code.
 919          *
 920          * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 921          * pmd_read_atomic is allowed to return a not atomic pmdval
 922          * (for example pointing to an hugepage that has never been
 923          * mapped in the pmd). The below checks will only care about
 924          * the low part of the pmd with 32bit PAE x86 anyway, with the
 925          * exception of pmd_none(). So the important thing is that if
 926          * the low part of the pmd is found null, the high part will
 927          * be also null or the pmd_none() check below would be
 928          * confused.
 929          */
 930 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 931         barrier();
 932 #endif
 933         /*
 934          * !pmd_present() checks for pmd migration entries
 935          *
 936          * The complete check uses is_pmd_migration_entry() in linux/swapops.h
 937          * But using that requires moving current function and pmd_trans_unstable()
 938          * to linux/swapops.h to resovle dependency, which is too much code move.
 939          *
 940          * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
 941          * because !pmd_present() pages can only be under migration not swapped
 942          * out.
 943          *
 944          * pmd_none() is preseved for future condition checks on pmd migration
 945          * entries and not confusing with this function name, although it is
 946          * redundant with !pmd_present().
 947          */
 948         if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
 949                 (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
 950                 return 1;
 951         if (unlikely(pmd_bad(pmdval))) {
 952                 pmd_clear_bad(pmd);
 953                 return 1;
 954         }
 955         return 0;
 956 }
 957
 958 /*
 959  * This is a noop if Transparent Hugepage Support is not built into
 960  * the kernel. Otherwise it is equivalent to
 961  * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 962  * places that already verified the pmd is not none and they want to
 963  * walk ptes while holding the mmap sem in read mode (write mode don't
 964  * need this). If THP is not enabled, the pmd can't go away under the
 965  * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 966  * run a pmd_trans_unstable before walking the ptes after
 967  * split_huge_page_pmd returns (because it may have run when the pmd
 968  * become null, but then a page fault can map in a THP and not a
 969  * regular page).
 970  */
 971 static inline int pmd_trans_unstable(pmd_t *pmd)
 972 {
 973 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 974         return pmd_none_or_trans_huge_or_clear_bad(pmd);
 975 #else
 976         return 0;
 977 #endif
 978 }
 979
 980 #ifndef CONFIG_NUMA_BALANCING
 981 /*
 982  * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
 983  * the only case the kernel cares is for NUMA balancing and is only ever set
 984  * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
 985  * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
 986  * is the responsibility of the caller to distinguish between PROT_NONE
 987  * protections and NUMA hinting fault protections.
 988  */
 989 static inline int pte_protnone(pte_t pte)
 990 {
 991         return 0;
 992 }
 993
 994 static inline int pmd_protnone(pmd_t pmd)
 995 {
 996         return 0;
 997 }
 998 #endif /* CONFIG_NUMA_BALANCING */
 999
1000 #endif /* CONFIG_MMU */
1001
1002 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
1003
1004 #ifndef __PAGETABLE_P4D_FOLDED
1005 int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
1006 int p4d_clear_huge(p4d_t *p4d);
1007 #else
1008 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1009 {
1010         return 0;
1011 }
1012 static inline int p4d_clear_huge(p4d_t *p4d)
1013 {
1014         return 0;
1015 }
1016 #endif /* !__PAGETABLE_P4D_FOLDED */
1017
1018 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
1019 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
1020 int pud_clear_huge(pud_t *pud);
1021 int pmd_clear_huge(pmd_t *pmd);
1022 int pud_free_pmd_page(pud_t *pud, unsigned long addr);
1023 int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
1024 #else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
1025 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1026 {
1027         return 0;
1028 }
1029 static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
1030 {
1031         return 0;
1032 }
1033 static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
1034 {
1035         return 0;
1036 }
1037 static inline int p4d_clear_huge(p4d_t *p4d)
1038 {
1039         return 0;
1040 }
1041 static inline int pud_clear_huge(pud_t *pud)
1042 {
1043         return 0;
1044 }
1045 static inline int pmd_clear_huge(pmd_t *pmd)
1046 {
1047         return 0;
1048 }
1049 static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
1050 {
1051         return 0;
1052 }
1053 static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
1054 {
1055         return 0;
1056 }
1057 #endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
1058
1059 #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
1060 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1061 /*
1062  * ARCHes with special requirements for evicting THP backing TLB entries can
1063  * implement this. Otherwise also, it can help optimize normal TLB flush in
1064  * THP regime. stock flush_tlb_range() typically has optimization to nuke the
1065  * entire TLB TLB if flush span is greater than a threshold, which will
1066  * likely be true for a single huge page. Thus a single thp flush will
1067  * invalidate the entire TLB which is not desitable.
1068  * e.g. see arch/arc: flush_pmd_tlb_range
1069  */
1070 #define flush_pmd_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1071 #define flush_pud_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1072 #else
1073 #define flush_pmd_tlb_range(vma, addr, end)     BUILD_BUG()
1074 #define flush_pud_tlb_range(vma, addr, end)     BUILD_BUG()
1075 #endif
1076 #endif
1077
1078 struct file;
1079 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
1080                         unsigned long size, pgprot_t *vma_prot);
1081
1082 #ifndef CONFIG_X86_ESPFIX64
1083 static inline void init_espfix_bsp(void) { }
1084 #endif
1085
1086 #ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
1087 static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
1088 {
1089         return true;
1090 }
1091
1092 static inline bool arch_has_pfn_modify_check(void)
1093 {
1094         return false;
1095 }
1096 #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
1097
1098 /*
1099  * Architecture PAGE_KERNEL_* fallbacks
1100  *
1101  * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
1102  * because they really don't support them, or the port needs to be updated to
1103  * reflect the required functionality. Below are a set of relatively safe
1104  * fallbacks, as best effort, which we can count on in lieu of the architectures
1105  * not defining them on their own yet.
1106  */
1107
1108 #ifndef PAGE_KERNEL_RO
1109 # define PAGE_KERNEL_RO PAGE_KERNEL
1110 #endif
1111
1112 #ifndef PAGE_KERNEL_EXEC
1113 # define PAGE_KERNEL_EXEC PAGE_KERNEL
1114 #endif
1115
1116 #endif /* !__ASSEMBLY__ */
1117
1118 #ifndef io_remap_pfn_range
1119 #define io_remap_pfn_range remap_pfn_range
1120 #endif
1121
1122 #ifndef has_transparent_hugepage
1123 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1124 #define has_transparent_hugepage() 1
1125 #else
1126 #define has_transparent_hugepage() 0
1127 #endif
1128 #endif
1129
1130 /*
1131  * On some architectures it depends on the mm if the p4d/pud or pmd
1132  * layer of the page table hierarchy is folded or not.
1133  */
1134 #ifndef mm_p4d_folded
1135 #define mm_p4d_folded(mm)       __is_defined(__PAGETABLE_P4D_FOLDED)
1136 #endif
1137
1138 #ifndef mm_pud_folded
1139 #define mm_pud_folded(mm)       __is_defined(__PAGETABLE_PUD_FOLDED)
1140 #endif
1141
1142 #ifndef mm_pmd_folded
1143 #define mm_pmd_folded(mm)       __is_defined(__PAGETABLE_PMD_FOLDED)
1144 #endif
1145
1146 #endif /* _ASM_GENERIC_PGTABLE_H */