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 #include <asm-generic/pgtable_uffd.h>
  14
  15 #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
  16         defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
  17 #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
  18 #endif
  19
  20 /*
  21  * On almost all architectures and configurations, 0 can be used as the
  22  * upper ceiling to free_pgtables(): on many architectures it has the same
  23  * effect as using TASK_SIZE.  However, there is one configuration which
  24  * must impose a more careful limit, to avoid freeing kernel pgtables.
  25  */
  26 #ifndef USER_PGTABLES_CEILING
  27 #define USER_PGTABLES_CEILING   0UL
  28 #endif
  29
  30 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  31 extern int ptep_set_access_flags(struct vm_area_struct *vma,
  32                                  unsigned long address, pte_t *ptep,
  33                                  pte_t entry, int dirty);
  34 #endif
  35
  36 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  37 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  38 extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  39                                  unsigned long address, pmd_t *pmdp,
  40                                  pmd_t entry, int dirty);
  41 extern int pudp_set_access_flags(struct vm_area_struct *vma,
  42                                  unsigned long address, pud_t *pudp,
  43                                  pud_t entry, int dirty);
  44 #else
  45 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
  46                                         unsigned long address, pmd_t *pmdp,
  47                                         pmd_t entry, int dirty)
  48 {
  49         BUILD_BUG();
  50         return 0;
  51 }
  52 static inline int pudp_set_access_flags(struct vm_area_struct *vma,
  53                                         unsigned long address, pud_t *pudp,
  54                                         pud_t entry, int dirty)
  55 {
  56         BUILD_BUG();
  57         return 0;
  58 }
  59 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  60 #endif
  61
  62 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  63 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
  64                                             unsigned long address,
  65                                             pte_t *ptep)
  66 {
  67         pte_t pte = *ptep;
  68         int r = 1;
  69         if (!pte_young(pte))
  70                 r = 0;
  71         else
  72                 set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
  73         return r;
  74 }
  75 #endif
  76
  77 #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
  78 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  79 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  80                                             unsigned long address,
  81                                             pmd_t *pmdp)
  82 {
  83         pmd_t pmd = *pmdp;
  84         int r = 1;
  85         if (!pmd_young(pmd))
  86                 r = 0;
  87         else
  88                 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
  89         return r;
  90 }
  91 #else
  92 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  93                                             unsigned long address,
  94                                             pmd_t *pmdp)
  95 {
  96         BUILD_BUG();
  97         return 0;
  98 }
  99 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 100 #endif
 101
 102 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 103 int ptep_clear_flush_young(struct vm_area_struct *vma,
 104                            unsigned long address, pte_t *ptep);
 105 #endif
 106
 107 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 108 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 109 extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 110                                   unsigned long address, pmd_t *pmdp);
 111 #else
 112 /*
 113  * Despite relevant to THP only, this API is called from generic rmap code
 114  * under PageTransHuge(), hence needs a dummy implementation for !THP
 115  */
 116 static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
 117                                          unsigned long address, pmd_t *pmdp)
 118 {
 119         BUILD_BUG();
 120         return 0;
 121 }
 122 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 123 #endif
 124
 125 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 126 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 127                                        unsigned long address,
 128                                        pte_t *ptep)
 129 {
 130         pte_t pte = *ptep;
 131         pte_clear(mm, address, ptep);
 132         return pte;
 133 }
 134 #endif
 135
 136 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 137 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
 138 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 139                                             unsigned long address,
 140                                             pmd_t *pmdp)
 141 {
 142         pmd_t pmd = *pmdp;
 143         pmd_clear(pmdp);
 144         return pmd;
 145 }
 146 #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
 147 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
 148 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
 149                                             unsigned long address,
 150                                             pud_t *pudp)
 151 {
 152         pud_t pud = *pudp;
 153
 154         pud_clear(pudp);
 155         return pud;
 156 }
 157 #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
 158 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 159
 160 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 161 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
 162 static inline pmd_t pmdp_huge_get_and_clear_full(struct mm_struct *mm,
 163                                             unsigned long address, pmd_t *pmdp,
 164                                             int full)
 165 {
 166         return pmdp_huge_get_and_clear(mm, address, pmdp);
 167 }
 168 #endif
 169
 170 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
 171 static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
 172                                             unsigned long address, pud_t *pudp,
 173                                             int full)
 174 {
 175         return pudp_huge_get_and_clear(mm, address, pudp);
 176 }
 177 #endif
 178 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 179
 180 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 181 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 182                                             unsigned long address, pte_t *ptep,
 183                                             int full)
 184 {
 185         pte_t pte;
 186         pte = ptep_get_and_clear(mm, address, ptep);
 187         return pte;
 188 }
 189 #endif
 190
 191 /*
 192  * Some architectures may be able to avoid expensive synchronization
 193  * primitives when modifications are made to PTE's which are already
 194  * not present, or in the process of an address space destruction.
 195  */
 196 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 197 static inline void pte_clear_not_present_full(struct mm_struct *mm,
 198                                               unsigned long address,
 199                                               pte_t *ptep,
 200                                               int full)
 201 {
 202         pte_clear(mm, address, ptep);
 203 }
 204 #endif
 205
 206 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 207 extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
 208                               unsigned long address,
 209                               pte_t *ptep);
 210 #endif
 211
 212 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 213 extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
 214                               unsigned long address,
 215                               pmd_t *pmdp);
 216 extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
 217                               unsigned long address,
 218                               pud_t *pudp);
 219 #endif
 220
 221 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 222 struct mm_struct;
 223 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 224 {
 225         pte_t old_pte = *ptep;
 226         set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 227 }
 228 #endif
 229
 230 #ifndef pte_savedwrite
 231 #define pte_savedwrite pte_write
 232 #endif
 233
 234 #ifndef pte_mk_savedwrite
 235 #define pte_mk_savedwrite pte_mkwrite
 236 #endif
 237
 238 #ifndef pte_clear_savedwrite
 239 #define pte_clear_savedwrite pte_wrprotect
 240 #endif
 241
 242 #ifndef pmd_savedwrite
 243 #define pmd_savedwrite pmd_write
 244 #endif
 245
 246 #ifndef pmd_mk_savedwrite
 247 #define pmd_mk_savedwrite pmd_mkwrite
 248 #endif
 249
 250 #ifndef pmd_clear_savedwrite
 251 #define pmd_clear_savedwrite pmd_wrprotect
 252 #endif
 253
 254 #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
 255 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 256 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 257                                       unsigned long address, pmd_t *pmdp)
 258 {
 259         pmd_t old_pmd = *pmdp;
 260         set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 261 }
 262 #else
 263 static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 264                                       unsigned long address, pmd_t *pmdp)
 265 {
 266         BUILD_BUG();
 267 }
 268 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 269 #endif
 270 #ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
 271 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 272 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 273                                       unsigned long address, pud_t *pudp)
 274 {
 275         pud_t old_pud = *pudp;
 276
 277         set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
 278 }
 279 #else
 280 static inline void pudp_set_wrprotect(struct mm_struct *mm,
 281                                       unsigned long address, pud_t *pudp)
 282 {
 283         BUILD_BUG();
 284 }
 285 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 286 #endif
 287
 288 #ifndef pmdp_collapse_flush
 289 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 290 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 291                                  unsigned long address, pmd_t *pmdp);
 292 #else
 293 static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 294                                         unsigned long address,
 295                                         pmd_t *pmdp)
 296 {
 297         BUILD_BUG();
 298         return *pmdp;
 299 }
 300 #define pmdp_collapse_flush pmdp_collapse_flush
 301 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 302 #endif
 303
 304 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 305 extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 306                                        pgtable_t pgtable);
 307 #endif
 308
 309 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 310 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 311 #endif
 312
 313 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 314 /*
 315  * This is an implementation of pmdp_establish() that is only suitable for an
 316  * architecture that doesn't have hardware dirty/accessed bits. In this case we
 317  * can't race with CPU which sets these bits and non-atomic aproach is fine.
 318  */
 319 static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
 320                 unsigned long address, pmd_t *pmdp, pmd_t pmd)
 321 {
 322         pmd_t old_pmd = *pmdp;
 323         set_pmd_at(vma->vm_mm, address, pmdp, pmd);
 324         return old_pmd;
 325 }
 326 #endif
 327
 328 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 329 extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 330                             pmd_t *pmdp);
 331 #endif
 332
 333 #ifndef __HAVE_ARCH_PTE_SAME
 334 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 335 {
 336         return pte_val(pte_a) == pte_val(pte_b);
 337 }
 338 #endif
 339
 340 #ifndef __HAVE_ARCH_PTE_UNUSED
 341 /*
 342  * Some architectures provide facilities to virtualization guests
 343  * so that they can flag allocated pages as unused. This allows the
 344  * host to transparently reclaim unused pages. This function returns
 345  * whether the pte's page is unused.
 346  */
 347 static inline int pte_unused(pte_t pte)
 348 {
 349         return 0;
 350 }
 351 #endif
 352
 353 #ifndef pte_access_permitted
 354 #define pte_access_permitted(pte, write) \
 355         (pte_present(pte) && (!(write) || pte_write(pte)))
 356 #endif
 357
 358 #ifndef pmd_access_permitted
 359 #define pmd_access_permitted(pmd, write) \
 360         (pmd_present(pmd) && (!(write) || pmd_write(pmd)))
 361 #endif
 362
 363 #ifndef pud_access_permitted
 364 #define pud_access_permitted(pud, write) \
 365         (pud_present(pud) && (!(write) || pud_write(pud)))
 366 #endif
 367
 368 #ifndef p4d_access_permitted
 369 #define p4d_access_permitted(p4d, write) \
 370         (p4d_present(p4d) && (!(write) || p4d_write(p4d)))
 371 #endif
 372
 373 #ifndef pgd_access_permitted
 374 #define pgd_access_permitted(pgd, write) \
 375         (pgd_present(pgd) && (!(write) || pgd_write(pgd)))
 376 #endif
 377
 378 #ifndef __HAVE_ARCH_PMD_SAME
 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 #endif
 389
 390 #ifndef __HAVE_ARCH_P4D_SAME
 391 static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
 392 {
 393         return p4d_val(p4d_a) == p4d_val(p4d_b);
 394 }
 395 #endif
 396
 397 #ifndef __HAVE_ARCH_PGD_SAME
 398 static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
 399 {
 400         return pgd_val(pgd_a) == pgd_val(pgd_b);
 401 }
 402 #endif
 403
 404 /*
 405  * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
 406  * TLB flush will be required as a result of the "set". For example, use
 407  * in scenarios where it is known ahead of time that the routine is
 408  * setting non-present entries, or re-setting an existing entry to the
 409  * same value. Otherwise, use the typical "set" helpers and flush the
 410  * TLB.
 411  */
 412 #define set_pte_safe(ptep, pte) \
 413 ({ \
 414         WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \
 415         set_pte(ptep, pte); \
 416 })
 417
 418 #define set_pmd_safe(pmdp, pmd) \
 419 ({ \
 420         WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \
 421         set_pmd(pmdp, pmd); \
 422 })
 423
 424 #define set_pud_safe(pudp, pud) \
 425 ({ \
 426         WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
 427         set_pud(pudp, pud); \
 428 })
 429
 430 #define set_p4d_safe(p4dp, p4d) \
 431 ({ \
 432         WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
 433         set_p4d(p4dp, p4d); \
 434 })
 435
 436 #define set_pgd_safe(pgdp, pgd) \
 437 ({ \
 438         WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \
 439         set_pgd(pgdp, pgd); \
 440 })
 441
 442 #ifndef __HAVE_ARCH_DO_SWAP_PAGE
 443 /*
 444  * Some architectures support metadata associated with a page. When a
 445  * page is being swapped out, this metadata must be saved so it can be
 446  * restored when the page is swapped back in. SPARC M7 and newer
 447  * processors support an ADI (Application Data Integrity) tag for the
 448  * page as metadata for the page. arch_do_swap_page() can restore this
 449  * metadata when a page is swapped back in.
 450  */
 451 static inline void arch_do_swap_page(struct mm_struct *mm,
 452                                      struct vm_area_struct *vma,
 453                                      unsigned long addr,
 454                                      pte_t pte, pte_t oldpte)
 455 {
 456
 457 }
 458 #endif
 459
 460 #ifndef __HAVE_ARCH_UNMAP_ONE
 461 /*
 462  * Some architectures support metadata associated with a page. When a
 463  * page is being swapped out, this metadata must be saved so it can be
 464  * restored when the page is swapped back in. SPARC M7 and newer
 465  * processors support an ADI (Application Data Integrity) tag for the
 466  * page as metadata for the page. arch_unmap_one() can save this
 467  * metadata on a swap-out of a page.
 468  */
 469 static inline int arch_unmap_one(struct mm_struct *mm,
 470                                   struct vm_area_struct *vma,
 471                                   unsigned long addr,
 472                                   pte_t orig_pte)
 473 {
 474         return 0;
 475 }
 476 #endif
 477
 478 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 479 #define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 480 #endif
 481
 482 #ifndef __HAVE_ARCH_MOVE_PTE
 483 #define move_pte(pte, prot, old_addr, new_addr) (pte)
 484 #endif
 485
 486 #ifndef pte_accessible
 487 # define pte_accessible(mm, pte)        ((void)(pte), 1)
 488 #endif
 489
 490 #ifndef flush_tlb_fix_spurious_fault
 491 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 492 #endif
 493
 494 #ifndef pgprot_nx
 495 #define pgprot_nx(prot) (prot)
 496 #endif
 497
 498 #ifndef pgprot_noncached
 499 #define pgprot_noncached(prot)  (prot)
 500 #endif
 501
 502 #ifndef pgprot_writecombine
 503 #define pgprot_writecombine pgprot_noncached
 504 #endif
 505
 506 #ifndef pgprot_writethrough
 507 #define pgprot_writethrough pgprot_noncached
 508 #endif
 509
 510 #ifndef pgprot_device
 511 #define pgprot_device pgprot_noncached
 512 #endif
 513
 514 #ifndef pgprot_modify
 515 #define pgprot_modify pgprot_modify
 516 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 517 {
 518         if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
 519                 newprot = pgprot_noncached(newprot);
 520         if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
 521                 newprot = pgprot_writecombine(newprot);
 522         if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
 523                 newprot = pgprot_device(newprot);
 524         return newprot;
 525 }
 526 #endif
 527
 528 /*
 529  * When walking page tables, get the address of the next boundary,
 530  * or the end address of the range if that comes earlier.  Although no
 531  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 532  */
 533
 534 #define pgd_addr_end(addr, end)                                         \
 535 ({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 536         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 537 })
 538
 539 #ifndef p4d_addr_end
 540 #define p4d_addr_end(addr, end)                                         \
 541 ({      unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;      \
 542         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 543 })
 544 #endif
 545
 546 #ifndef pud_addr_end
 547 #define pud_addr_end(addr, end)                                         \
 548 ({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 549         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 550 })
 551 #endif
 552
 553 #ifndef pmd_addr_end
 554 #define pmd_addr_end(addr, end)                                         \
 555 ({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 556         (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 557 })
 558 #endif
 559
 560 /*
 561  * When walking page tables, we usually want to skip any p?d_none entries;
 562  * and any p?d_bad entries - reporting the error before resetting to none.
 563  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 564  */
 565 void pgd_clear_bad(pgd_t *);
 566
 567 #ifndef __PAGETABLE_P4D_FOLDED
 568 void p4d_clear_bad(p4d_t *);
 569 #else
 570 #define p4d_clear_bad(p4d)        do { } while (0)
 571 #endif
 572
 573 #ifndef __PAGETABLE_PUD_FOLDED
 574 void pud_clear_bad(pud_t *);
 575 #else
 576 #define pud_clear_bad(p4d)        do { } while (0)
 577 #endif
 578
 579 void pmd_clear_bad(pmd_t *);
 580
 581 static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 582 {
 583         if (pgd_none(*pgd))
 584                 return 1;
 585         if (unlikely(pgd_bad(*pgd))) {
 586                 pgd_clear_bad(pgd);
 587                 return 1;
 588         }
 589         return 0;
 590 }
 591
 592 static inline int p4d_none_or_clear_bad(p4d_t *p4d)
 593 {
 594         if (p4d_none(*p4d))
 595                 return 1;
 596         if (unlikely(p4d_bad(*p4d))) {
 597                 p4d_clear_bad(p4d);
 598                 return 1;
 599         }
 600         return 0;
 601 }
 602
 603 static inline int pud_none_or_clear_bad(pud_t *pud)
 604 {
 605         if (pud_none(*pud))
 606                 return 1;
 607         if (unlikely(pud_bad(*pud))) {
 608                 pud_clear_bad(pud);
 609                 return 1;
 610         }
 611         return 0;
 612 }
 613
 614 static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 615 {
 616         if (pmd_none(*pmd))
 617                 return 1;
 618         if (unlikely(pmd_bad(*pmd))) {
 619                 pmd_clear_bad(pmd);
 620                 return 1;
 621         }
 622         return 0;
 623 }
 624
 625 static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma,
 626                                              unsigned long addr,
 627                                              pte_t *ptep)
 628 {
 629         /*
 630          * Get the current pte state, but zero it out to make it
 631          * non-present, preventing the hardware from asynchronously
 632          * updating it.
 633          */
 634         return ptep_get_and_clear(vma->vm_mm, addr, ptep);
 635 }
 636
 637 static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma,
 638                                              unsigned long addr,
 639                                              pte_t *ptep, pte_t pte)
 640 {
 641         /*
 642          * The pte is non-present, so there's no hardware state to
 643          * preserve.
 644          */
 645         set_pte_at(vma->vm_mm, addr, ptep, pte);
 646 }
 647
 648 #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 649 /*
 650  * Start a pte protection read-modify-write transaction, which
 651  * protects against asynchronous hardware modifications to the pte.
 652  * The intention is not to prevent the hardware from making pte
 653  * updates, but to prevent any updates it may make from being lost.
 654  *
 655  * This does not protect against other software modifications of the
 656  * pte; the appropriate pte lock must be held over the transation.
 657  *
 658  * Note that this interface is intended to be batchable, meaning that
 659  * ptep_modify_prot_commit may not actually update the pte, but merely
 660  * queue the update to be done at some later time.  The update must be
 661  * actually committed before the pte lock is released, however.
 662  */
 663 static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
 664                                            unsigned long addr,
 665                                            pte_t *ptep)
 666 {
 667         return __ptep_modify_prot_start(vma, addr, ptep);
 668 }
 669
 670 /*
 671  * Commit an update to a pte, leaving any hardware-controlled bits in
 672  * the PTE unmodified.
 673  */
 674 static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
 675                                            unsigned long addr,
 676                                            pte_t *ptep, pte_t old_pte, pte_t pte)
 677 {
 678         __ptep_modify_prot_commit(vma, addr, ptep, pte);
 679 }
 680 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 681 #endif /* CONFIG_MMU */
 682
 683 /*
 684  * No-op macros that just return the current protection value. Defined here
 685  * because these macros can be used used even if CONFIG_MMU is not defined.
 686  */
 687 #ifndef pgprot_encrypted
 688 #define pgprot_encrypted(prot)  (prot)
 689 #endif
 690
 691 #ifndef pgprot_decrypted
 692 #define pgprot_decrypted(prot)  (prot)
 693 #endif
 694
 695 /*
 696  * A facility to provide lazy MMU batching.  This allows PTE updates and
 697  * page invalidations to be delayed until a call to leave lazy MMU mode
 698  * is issued.  Some architectures may benefit from doing this, and it is
 699  * beneficial for both shadow and direct mode hypervisors, which may batch
 700  * the PTE updates which happen during this window.  Note that using this
 701  * interface requires that read hazards be removed from the code.  A read
 702  * hazard could result in the direct mode hypervisor case, since the actual
 703  * write to the page tables may not yet have taken place, so reads though
 704  * a raw PTE pointer after it has been modified are not guaranteed to be
 705  * up to date.  This mode can only be entered and left under the protection of
 706  * the page table locks for all page tables which may be modified.  In the UP
 707  * case, this is required so that preemption is disabled, and in the SMP case,
 708  * it must synchronize the delayed page table writes properly on other CPUs.
 709  */
 710 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 711 #define arch_enter_lazy_mmu_mode()      do {} while (0)
 712 #define arch_leave_lazy_mmu_mode()      do {} while (0)
 713 #define arch_flush_lazy_mmu_mode()      do {} while (0)
 714 #endif
 715
 716 /*
 717  * A facility to provide batching of the reload of page tables and
 718  * other process state with the actual context switch code for
 719  * paravirtualized guests.  By convention, only one of the batched
 720  * update (lazy) modes (CPU, MMU) should be active at any given time,
 721  * entry should never be nested, and entry and exits should always be
 722  * paired.  This is for sanity of maintaining and reasoning about the
 723  * kernel code.  In this case, the exit (end of the context switch) is
 724  * in architecture-specific code, and so doesn't need a generic
 725  * definition.
 726  */
 727 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 728 #define arch_start_context_switch(prev) do {} while (0)
 729 #endif
 730
 731 #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
 732 #ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
 733 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 734 {
 735         return pmd;
 736 }
 737
 738 static inline int pmd_swp_soft_dirty(pmd_t pmd)
 739 {
 740         return 0;
 741 }
 742
 743 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 744 {
 745         return pmd;
 746 }
 747 #endif
 748 #else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
 749 static inline int pte_soft_dirty(pte_t pte)
 750 {
 751         return 0;
 752 }
 753
 754 static inline int pmd_soft_dirty(pmd_t pmd)
 755 {
 756         return 0;
 757 }
 758
 759 static inline pte_t pte_mksoft_dirty(pte_t pte)
 760 {
 761         return pte;
 762 }
 763
 764 static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 765 {
 766         return pmd;
 767 }
 768
 769 static inline pte_t pte_clear_soft_dirty(pte_t pte)
 770 {
 771         return pte;
 772 }
 773
 774 static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
 775 {
 776         return pmd;
 777 }
 778
 779 static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 780 {
 781         return pte;
 782 }
 783
 784 static inline int pte_swp_soft_dirty(pte_t pte)
 785 {
 786         return 0;
 787 }
 788
 789 static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 790 {
 791         return pte;
 792 }
 793
 794 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 795 {
 796         return pmd;
 797 }
 798
 799 static inline int pmd_swp_soft_dirty(pmd_t pmd)
 800 {
 801         return 0;
 802 }
 803
 804 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 805 {
 806         return pmd;
 807 }
 808 #endif
 809
 810 #ifndef __HAVE_PFNMAP_TRACKING
 811 /*
 812  * Interfaces that can be used by architecture code to keep track of
 813  * memory type of pfn mappings specified by the remap_pfn_range,
 814  * vmf_insert_pfn.
 815  */
 816
 817 /*
 818  * track_pfn_remap is called when a _new_ pfn mapping is being established
 819  * by remap_pfn_range() for physical range indicated by pfn and size.
 820  */
 821 static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 822                                   unsigned long pfn, unsigned long addr,
 823                                   unsigned long size)
 824 {
 825         return 0;
 826 }
 827
 828 /*
 829  * track_pfn_insert is called when a _new_ single pfn is established
 830  * by vmf_insert_pfn().
 831  */
 832 static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 833                                     pfn_t pfn)
 834 {
 835 }
 836
 837 /*
 838  * track_pfn_copy is called when vma that is covering the pfnmap gets
 839  * copied through copy_page_range().
 840  */
 841 static inline int track_pfn_copy(struct vm_area_struct *vma)
 842 {
 843         return 0;
 844 }
 845
 846 /*
 847  * untrack_pfn is called while unmapping a pfnmap for a region.
 848  * untrack can be called for a specific region indicated by pfn and size or
 849  * can be for the entire vma (in which case pfn, size are zero).
 850  */
 851 static inline void untrack_pfn(struct vm_area_struct *vma,
 852                                unsigned long pfn, unsigned long size)
 853 {
 854 }
 855
 856 /*
 857  * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
 858  */
 859 static inline void untrack_pfn_moved(struct vm_area_struct *vma)
 860 {
 861 }
 862 #else
 863 extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 864                            unsigned long pfn, unsigned long addr,
 865                            unsigned long size);
 866 extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 867                              pfn_t pfn);
 868 extern int track_pfn_copy(struct vm_area_struct *vma);
 869 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 870                         unsigned long size);
 871 extern void untrack_pfn_moved(struct vm_area_struct *vma);
 872 #endif
 873
 874 #ifdef __HAVE_COLOR_ZERO_PAGE
 875 static inline int is_zero_pfn(unsigned long pfn)
 876 {
 877         extern unsigned long zero_pfn;
 878         unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 879         return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 880 }
 881
 882 #define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 883
 884 #else
 885 static inline int is_zero_pfn(unsigned long pfn)
 886 {
 887         extern unsigned long zero_pfn;
 888         return pfn == zero_pfn;
 889 }
 890
 891 static inline unsigned long my_zero_pfn(unsigned long addr)
 892 {
 893         extern unsigned long zero_pfn;
 894         return zero_pfn;
 895 }
 896 #endif
 897
 898 #ifdef CONFIG_MMU
 899
 900 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 901 static inline int pmd_trans_huge(pmd_t pmd)
 902 {
 903         return 0;
 904 }
 905 #ifndef pmd_write
 906 static inline int pmd_write(pmd_t pmd)
 907 {
 908         BUG();
 909         return 0;
 910 }
 911 #endif /* pmd_write */
 912 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 913
 914 #ifndef pud_write
 915 static inline int pud_write(pud_t pud)
 916 {
 917         BUG();
 918         return 0;
 919 }
 920 #endif /* pud_write */
 921
 922 #if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
 923 static inline int pmd_devmap(pmd_t pmd)
 924 {
 925         return 0;
 926 }
 927 static inline int pud_devmap(pud_t pud)
 928 {
 929         return 0;
 930 }
 931 static inline int pgd_devmap(pgd_t pgd)
 932 {
 933         return 0;
 934 }
 935 #endif
 936
 937 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 938         (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 939          !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 940 static inline int pud_trans_huge(pud_t pud)
 941 {
 942         return 0;
 943 }
 944 #endif
 945
 946 /* See pmd_none_or_trans_huge_or_clear_bad for discussion. */
 947 static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud)
 948 {
 949         pud_t pudval = READ_ONCE(*pud);
 950
 951         if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
 952                 return 1;
 953         if (unlikely(pud_bad(pudval))) {
 954                 pud_clear_bad(pud);
 955                 return 1;
 956         }
 957         return 0;
 958 }
 959
 960 /* See pmd_trans_unstable for discussion. */
 961 static inline int pud_trans_unstable(pud_t *pud)
 962 {
 963 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) &&                     \
 964         defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
 965         return pud_none_or_trans_huge_or_dev_or_clear_bad(pud);
 966 #else
 967         return 0;
 968 #endif
 969 }
 970
 971 #ifndef pmd_read_atomic
 972 static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 973 {
 974         /*
 975          * Depend on compiler for an atomic pmd read. NOTE: this is
 976          * only going to work, if the pmdval_t isn't larger than
 977          * an unsigned long.
 978          */
 979         return *pmdp;
 980 }
 981 #endif
 982
 983 #ifndef arch_needs_pgtable_deposit
 984 #define arch_needs_pgtable_deposit() (false)
 985 #endif
 986 /*
 987  * This function is meant to be used by sites walking pagetables with
 988  * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 989  * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 990  * into a null pmd and the transhuge page fault can convert a null pmd
 991  * into an hugepmd or into a regular pmd (if the hugepage allocation
 992  * fails). While holding the mmap_sem in read mode the pmd becomes
 993  * stable and stops changing under us only if it's not null and not a
 994  * transhuge pmd. When those races occurs and this function makes a
 995  * difference vs the standard pmd_none_or_clear_bad, the result is
 996  * undefined so behaving like if the pmd was none is safe (because it
 997  * can return none anyway). The compiler level barrier() is critically
 998  * important to compute the two checks atomically on the same pmdval.
 999  *
1000  * For 32bit kernels with a 64bit large pmd_t this automatically takes
1001  * care of reading the pmd atomically to avoid SMP race conditions
1002  * against pmd_populate() when the mmap_sem is hold for reading by the
1003  * caller (a special atomic read not done by "gcc" as in the generic
1004  * version above, is also needed when THP is disabled because the page
1005  * fault can populate the pmd from under us).
1006  */
1007 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
1008 {
1009         pmd_t pmdval = pmd_read_atomic(pmd);
1010         /*
1011          * The barrier will stabilize the pmdval in a register or on
1012          * the stack so that it will stop changing under the code.
1013          *
1014          * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
1015          * pmd_read_atomic is allowed to return a not atomic pmdval
1016          * (for example pointing to an hugepage that has never been
1017          * mapped in the pmd). The below checks will only care about
1018          * the low part of the pmd with 32bit PAE x86 anyway, with the
1019          * exception of pmd_none(). So the important thing is that if
1020          * the low part of the pmd is found null, the high part will
1021          * be also null or the pmd_none() check below would be
1022          * confused.
1023          */
1024 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1025         barrier();
1026 #endif
1027         /*
1028          * !pmd_present() checks for pmd migration entries
1029          *
1030          * The complete check uses is_pmd_migration_entry() in linux/swapops.h
1031          * But using that requires moving current function and pmd_trans_unstable()
1032          * to linux/swapops.h to resovle dependency, which is too much code move.
1033          *
1034          * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
1035          * because !pmd_present() pages can only be under migration not swapped
1036          * out.
1037          *
1038          * pmd_none() is preseved for future condition checks on pmd migration
1039          * entries and not confusing with this function name, although it is
1040          * redundant with !pmd_present().
1041          */
1042         if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
1043                 (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
1044                 return 1;
1045         if (unlikely(pmd_bad(pmdval))) {
1046                 pmd_clear_bad(pmd);
1047                 return 1;
1048         }
1049         return 0;
1050 }
1051
1052 /*
1053  * This is a noop if Transparent Hugepage Support is not built into
1054  * the kernel. Otherwise it is equivalent to
1055  * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
1056  * places that already verified the pmd is not none and they want to
1057  * walk ptes while holding the mmap sem in read mode (write mode don't
1058  * need this). If THP is not enabled, the pmd can't go away under the
1059  * code even if MADV_DONTNEED runs, but if THP is enabled we need to
1060  * run a pmd_trans_unstable before walking the ptes after
1061  * split_huge_pmd returns (because it may have run when the pmd become
1062  * null, but then a page fault can map in a THP and not a regular page).
1063  */
1064 static inline int pmd_trans_unstable(pmd_t *pmd)
1065 {
1066 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1067         return pmd_none_or_trans_huge_or_clear_bad(pmd);
1068 #else
1069         return 0;
1070 #endif
1071 }
1072
1073 #ifndef CONFIG_NUMA_BALANCING
1074 /*
1075  * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
1076  * the only case the kernel cares is for NUMA balancing and is only ever set
1077  * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
1078  * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
1079  * is the responsibility of the caller to distinguish between PROT_NONE
1080  * protections and NUMA hinting fault protections.
1081  */
1082 static inline int pte_protnone(pte_t pte)
1083 {
1084         return 0;
1085 }
1086
1087 static inline int pmd_protnone(pmd_t pmd)
1088 {
1089         return 0;
1090 }
1091 #endif /* CONFIG_NUMA_BALANCING */
1092
1093 #endif /* CONFIG_MMU */
1094
1095 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
1096
1097 #ifndef __PAGETABLE_P4D_FOLDED
1098 int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
1099 int p4d_clear_huge(p4d_t *p4d);
1100 #else
1101 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1102 {
1103         return 0;
1104 }
1105 static inline int p4d_clear_huge(p4d_t *p4d)
1106 {
1107         return 0;
1108 }
1109 #endif /* !__PAGETABLE_P4D_FOLDED */
1110
1111 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
1112 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
1113 int pud_clear_huge(pud_t *pud);
1114 int pmd_clear_huge(pmd_t *pmd);
1115 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
1116 int pud_free_pmd_page(pud_t *pud, unsigned long addr);
1117 int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
1118 #else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
1119 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1120 {
1121         return 0;
1122 }
1123 static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
1124 {
1125         return 0;
1126 }
1127 static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
1128 {
1129         return 0;
1130 }
1131 static inline int p4d_clear_huge(p4d_t *p4d)
1132 {
1133         return 0;
1134 }
1135 static inline int pud_clear_huge(pud_t *pud)
1136 {
1137         return 0;
1138 }
1139 static inline int pmd_clear_huge(pmd_t *pmd)
1140 {
1141         return 0;
1142 }
1143 static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1144 {
1145         return 0;
1146 }
1147 static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
1148 {
1149         return 0;
1150 }
1151 static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
1152 {
1153         return 0;
1154 }
1155 #endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
1156
1157 #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
1158 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1159 /*
1160  * ARCHes with special requirements for evicting THP backing TLB entries can
1161  * implement this. Otherwise also, it can help optimize normal TLB flush in
1162  * THP regime. stock flush_tlb_range() typically has optimization to nuke the
1163  * entire TLB TLB if flush span is greater than a threshold, which will
1164  * likely be true for a single huge page. Thus a single thp flush will
1165  * invalidate the entire TLB which is not desitable.
1166  * e.g. see arch/arc: flush_pmd_tlb_range
1167  */
1168 #define flush_pmd_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1169 #define flush_pud_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1170 #else
1171 #define flush_pmd_tlb_range(vma, addr, end)     BUILD_BUG()
1172 #define flush_pud_tlb_range(vma, addr, end)     BUILD_BUG()
1173 #endif
1174 #endif
1175
1176 struct file;
1177 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
1178                         unsigned long size, pgprot_t *vma_prot);
1179
1180 #ifndef CONFIG_X86_ESPFIX64
1181 static inline void init_espfix_bsp(void) { }
1182 #endif
1183
1184 extern void __init pgtable_cache_init(void);
1185
1186 #ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
1187 static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
1188 {
1189         return true;
1190 }
1191
1192 static inline bool arch_has_pfn_modify_check(void)
1193 {
1194         return false;
1195 }
1196 #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
1197
1198 /*
1199  * Architecture PAGE_KERNEL_* fallbacks
1200  *
1201  * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
1202  * because they really don't support them, or the port needs to be updated to
1203  * reflect the required functionality. Below are a set of relatively safe
1204  * fallbacks, as best effort, which we can count on in lieu of the architectures
1205  * not defining them on their own yet.
1206  */
1207
1208 #ifndef PAGE_KERNEL_RO
1209 # define PAGE_KERNEL_RO PAGE_KERNEL
1210 #endif
1211
1212 #ifndef PAGE_KERNEL_EXEC
1213 # define PAGE_KERNEL_EXEC PAGE_KERNEL
1214 #endif
1215
1216 #endif /* !__ASSEMBLY__ */
1217
1218 #ifndef io_remap_pfn_range
1219 #define io_remap_pfn_range remap_pfn_range
1220 #endif
1221
1222 #ifndef has_transparent_hugepage
1223 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1224 #define has_transparent_hugepage() 1
1225 #else
1226 #define has_transparent_hugepage() 0
1227 #endif
1228 #endif
1229
1230 /*
1231  * On some architectures it depends on the mm if the p4d/pud or pmd
1232  * layer of the page table hierarchy is folded or not.
1233  */
1234 #ifndef mm_p4d_folded
1235 #define mm_p4d_folded(mm)       __is_defined(__PAGETABLE_P4D_FOLDED)
1236 #endif
1237
1238 #ifndef mm_pud_folded
1239 #define mm_pud_folded(mm)       __is_defined(__PAGETABLE_PUD_FOLDED)
1240 #endif
1241
1242 #ifndef mm_pmd_folded
1243 #define mm_pmd_folded(mm)       __is_defined(__PAGETABLE_PMD_FOLDED)
1244 #endif
1245
1246 /*
1247  * p?d_leaf() - true if this entry is a final mapping to a physical address.
1248  * This differs from p?d_huge() by the fact that they are always available (if
1249  * the architecture supports large pages at the appropriate level) even
1250  * if CONFIG_HUGETLB_PAGE is not defined.
1251  * Only meaningful when called on a valid entry.
1252  */
1253 #ifndef pgd_leaf
1254 #define pgd_leaf(x)     0
1255 #endif
1256 #ifndef p4d_leaf
1257 #define p4d_leaf(x)     0
1258 #endif
1259 #ifndef pud_leaf
1260 #define pud_leaf(x)     0
1261 #endif
1262 #ifndef pmd_leaf
1263 #define pmd_leaf(x)     0
1264 #endif
1265
1266 #endif /* _ASM_GENERIC_PGTABLE_H */