linux/include/asm-generic/pgtable.h
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   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
  30extern 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
  37extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  38                                 unsigned long address, pmd_t *pmdp,
  39                                 pmd_t entry, int dirty);
  40extern 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
  44static 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}
  51static 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
  62static 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
  78static 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
  91static 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
 102int 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
 108extern 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 */
 115static 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
 125static 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
 137static 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
 147static 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
 161static 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
 170static 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
 180static 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
 196static 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
 206extern 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
 212extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
 213                              unsigned long address,
 214                              pmd_t *pmdp);
 215extern 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
 221struct mm_struct;
 222static 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
 255static 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
 262static 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
 271static 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
 279static 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
 289extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 290                                 unsigned long address, pmd_t *pmdp);
 291#else
 292static 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
 304extern 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
 309extern 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 */
 318static 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
 328extern 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
 333static 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 */
 346static 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
 378static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 379{
 380        return pmd_val(pmd_a) == pmd_val(pmd_b);
 381}
 382
 383static inline int pud_same(pud_t pud_a, pud_t pud_b)
 384{
 385        return pud_val(pud_a) == pud_val(pud_b);
 386}
 387#endif
 388
 389#ifndef __HAVE_ARCH_P4D_SAME
 390static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
 391{
 392        return p4d_val(p4d_a) == p4d_val(p4d_b);
 393}
 394#endif
 395
 396#ifndef __HAVE_ARCH_PGD_SAME
 397static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
 398{
 399        return pgd_val(pgd_a) == pgd_val(pgd_b);
 400}
 401#endif
 402
 403/*
 404 * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
 405 * TLB flush will be required as a result of the "set". For example, use
 406 * in scenarios where it is known ahead of time that the routine is
 407 * setting non-present entries, or re-setting an existing entry to the
 408 * same value. Otherwise, use the typical "set" helpers and flush the
 409 * TLB.
 410 */
 411#define set_pte_safe(ptep, pte) \
 412({ \
 413        WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \
 414        set_pte(ptep, pte); \
 415})
 416
 417#define set_pmd_safe(pmdp, pmd) \
 418({ \
 419        WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \
 420        set_pmd(pmdp, pmd); \
 421})
 422
 423#define set_pud_safe(pudp, pud) \
 424({ \
 425        WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
 426        set_pud(pudp, pud); \
 427})
 428
 429#define set_p4d_safe(p4dp, p4d) \
 430({ \
 431        WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
 432        set_p4d(p4dp, p4d); \
 433})
 434
 435#define set_pgd_safe(pgdp, pgd) \
 436({ \
 437        WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \
 438        set_pgd(pgdp, pgd); \
 439})
 440
 441#ifndef __HAVE_ARCH_DO_SWAP_PAGE
 442/*
 443 * Some architectures support metadata associated with a page. When a
 444 * page is being swapped out, this metadata must be saved so it can be
 445 * restored when the page is swapped back in. SPARC M7 and newer
 446 * processors support an ADI (Application Data Integrity) tag for the
 447 * page as metadata for the page. arch_do_swap_page() can restore this
 448 * metadata when a page is swapped back in.
 449 */
 450static inline void arch_do_swap_page(struct mm_struct *mm,
 451                                     struct vm_area_struct *vma,
 452                                     unsigned long addr,
 453                                     pte_t pte, pte_t oldpte)
 454{
 455
 456}
 457#endif
 458
 459#ifndef __HAVE_ARCH_UNMAP_ONE
 460/*
 461 * Some architectures support metadata associated with a page. When a
 462 * page is being swapped out, this metadata must be saved so it can be
 463 * restored when the page is swapped back in. SPARC M7 and newer
 464 * processors support an ADI (Application Data Integrity) tag for the
 465 * page as metadata for the page. arch_unmap_one() can save this
 466 * metadata on a swap-out of a page.
 467 */
 468static inline int arch_unmap_one(struct mm_struct *mm,
 469                                  struct vm_area_struct *vma,
 470                                  unsigned long addr,
 471                                  pte_t orig_pte)
 472{
 473        return 0;
 474}
 475#endif
 476
 477#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 478#define pgd_offset_gate(mm, addr)       pgd_offset(mm, addr)
 479#endif
 480
 481#ifndef __HAVE_ARCH_MOVE_PTE
 482#define move_pte(pte, prot, old_addr, new_addr) (pte)
 483#endif
 484
 485#ifndef pte_accessible
 486# define pte_accessible(mm, pte)        ((void)(pte), 1)
 487#endif
 488
 489#ifndef flush_tlb_fix_spurious_fault
 490#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 491#endif
 492
 493#ifndef pgprot_noncached
 494#define pgprot_noncached(prot)  (prot)
 495#endif
 496
 497#ifndef pgprot_writecombine
 498#define pgprot_writecombine pgprot_noncached
 499#endif
 500
 501#ifndef pgprot_writethrough
 502#define pgprot_writethrough pgprot_noncached
 503#endif
 504
 505#ifndef pgprot_device
 506#define pgprot_device pgprot_noncached
 507#endif
 508
 509#ifndef pgprot_modify
 510#define pgprot_modify pgprot_modify
 511static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 512{
 513        if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
 514                newprot = pgprot_noncached(newprot);
 515        if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
 516                newprot = pgprot_writecombine(newprot);
 517        if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
 518                newprot = pgprot_device(newprot);
 519        return newprot;
 520}
 521#endif
 522
 523/*
 524 * When walking page tables, get the address of the next boundary,
 525 * or the end address of the range if that comes earlier.  Although no
 526 * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 527 */
 528
 529#define pgd_addr_end(addr, end)                                         \
 530({      unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
 531        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 532})
 533
 534#ifndef p4d_addr_end
 535#define p4d_addr_end(addr, end)                                         \
 536({      unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;      \
 537        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 538})
 539#endif
 540
 541#ifndef pud_addr_end
 542#define pud_addr_end(addr, end)                                         \
 543({      unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;      \
 544        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 545})
 546#endif
 547
 548#ifndef pmd_addr_end
 549#define pmd_addr_end(addr, end)                                         \
 550({      unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;      \
 551        (__boundary - 1 < (end) - 1)? __boundary: (end);                \
 552})
 553#endif
 554
 555/*
 556 * When walking page tables, we usually want to skip any p?d_none entries;
 557 * and any p?d_bad entries - reporting the error before resetting to none.
 558 * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 559 */
 560void pgd_clear_bad(pgd_t *);
 561void p4d_clear_bad(p4d_t *);
 562void pud_clear_bad(pud_t *);
 563void pmd_clear_bad(pmd_t *);
 564
 565static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 566{
 567        if (pgd_none(*pgd))
 568                return 1;
 569        if (unlikely(pgd_bad(*pgd))) {
 570                pgd_clear_bad(pgd);
 571                return 1;
 572        }
 573        return 0;
 574}
 575
 576static inline int p4d_none_or_clear_bad(p4d_t *p4d)
 577{
 578        if (p4d_none(*p4d))
 579                return 1;
 580        if (unlikely(p4d_bad(*p4d))) {
 581                p4d_clear_bad(p4d);
 582                return 1;
 583        }
 584        return 0;
 585}
 586
 587static inline int pud_none_or_clear_bad(pud_t *pud)
 588{
 589        if (pud_none(*pud))
 590                return 1;
 591        if (unlikely(pud_bad(*pud))) {
 592                pud_clear_bad(pud);
 593                return 1;
 594        }
 595        return 0;
 596}
 597
 598static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 599{
 600        if (pmd_none(*pmd))
 601                return 1;
 602        if (unlikely(pmd_bad(*pmd))) {
 603                pmd_clear_bad(pmd);
 604                return 1;
 605        }
 606        return 0;
 607}
 608
 609static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma,
 610                                             unsigned long addr,
 611                                             pte_t *ptep)
 612{
 613        /*
 614         * Get the current pte state, but zero it out to make it
 615         * non-present, preventing the hardware from asynchronously
 616         * updating it.
 617         */
 618        return ptep_get_and_clear(vma->vm_mm, addr, ptep);
 619}
 620
 621static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma,
 622                                             unsigned long addr,
 623                                             pte_t *ptep, pte_t pte)
 624{
 625        /*
 626         * The pte is non-present, so there's no hardware state to
 627         * preserve.
 628         */
 629        set_pte_at(vma->vm_mm, addr, ptep, pte);
 630}
 631
 632#ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 633/*
 634 * Start a pte protection read-modify-write transaction, which
 635 * protects against asynchronous hardware modifications to the pte.
 636 * The intention is not to prevent the hardware from making pte
 637 * updates, but to prevent any updates it may make from being lost.
 638 *
 639 * This does not protect against other software modifications of the
 640 * pte; the appropriate pte lock must be held over the transation.
 641 *
 642 * Note that this interface is intended to be batchable, meaning that
 643 * ptep_modify_prot_commit may not actually update the pte, but merely
 644 * queue the update to be done at some later time.  The update must be
 645 * actually committed before the pte lock is released, however.
 646 */
 647static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
 648                                           unsigned long addr,
 649                                           pte_t *ptep)
 650{
 651        return __ptep_modify_prot_start(vma, addr, ptep);
 652}
 653
 654/*
 655 * Commit an update to a pte, leaving any hardware-controlled bits in
 656 * the PTE unmodified.
 657 */
 658static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
 659                                           unsigned long addr,
 660                                           pte_t *ptep, pte_t old_pte, pte_t pte)
 661{
 662        __ptep_modify_prot_commit(vma, addr, ptep, pte);
 663}
 664#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 665#endif /* CONFIG_MMU */
 666
 667/*
 668 * No-op macros that just return the current protection value. Defined here
 669 * because these macros can be used used even if CONFIG_MMU is not defined.
 670 */
 671#ifndef pgprot_encrypted
 672#define pgprot_encrypted(prot)  (prot)
 673#endif
 674
 675#ifndef pgprot_decrypted
 676#define pgprot_decrypted(prot)  (prot)
 677#endif
 678
 679/*
 680 * A facility to provide lazy MMU batching.  This allows PTE updates and
 681 * page invalidations to be delayed until a call to leave lazy MMU mode
 682 * is issued.  Some architectures may benefit from doing this, and it is
 683 * beneficial for both shadow and direct mode hypervisors, which may batch
 684 * the PTE updates which happen during this window.  Note that using this
 685 * interface requires that read hazards be removed from the code.  A read
 686 * hazard could result in the direct mode hypervisor case, since the actual
 687 * write to the page tables may not yet have taken place, so reads though
 688 * a raw PTE pointer after it has been modified are not guaranteed to be
 689 * up to date.  This mode can only be entered and left under the protection of
 690 * the page table locks for all page tables which may be modified.  In the UP
 691 * case, this is required so that preemption is disabled, and in the SMP case,
 692 * it must synchronize the delayed page table writes properly on other CPUs.
 693 */
 694#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 695#define arch_enter_lazy_mmu_mode()      do {} while (0)
 696#define arch_leave_lazy_mmu_mode()      do {} while (0)
 697#define arch_flush_lazy_mmu_mode()      do {} while (0)
 698#endif
 699
 700/*
 701 * A facility to provide batching of the reload of page tables and
 702 * other process state with the actual context switch code for
 703 * paravirtualized guests.  By convention, only one of the batched
 704 * update (lazy) modes (CPU, MMU) should be active at any given time,
 705 * entry should never be nested, and entry and exits should always be
 706 * paired.  This is for sanity of maintaining and reasoning about the
 707 * kernel code.  In this case, the exit (end of the context switch) is
 708 * in architecture-specific code, and so doesn't need a generic
 709 * definition.
 710 */
 711#ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 712#define arch_start_context_switch(prev) do {} while (0)
 713#endif
 714
 715#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
 716#ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
 717static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 718{
 719        return pmd;
 720}
 721
 722static inline int pmd_swp_soft_dirty(pmd_t pmd)
 723{
 724        return 0;
 725}
 726
 727static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 728{
 729        return pmd;
 730}
 731#endif
 732#else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
 733static inline int pte_soft_dirty(pte_t pte)
 734{
 735        return 0;
 736}
 737
 738static inline int pmd_soft_dirty(pmd_t pmd)
 739{
 740        return 0;
 741}
 742
 743static inline pte_t pte_mksoft_dirty(pte_t pte)
 744{
 745        return pte;
 746}
 747
 748static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 749{
 750        return pmd;
 751}
 752
 753static inline pte_t pte_clear_soft_dirty(pte_t pte)
 754{
 755        return pte;
 756}
 757
 758static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
 759{
 760        return pmd;
 761}
 762
 763static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 764{
 765        return pte;
 766}
 767
 768static inline int pte_swp_soft_dirty(pte_t pte)
 769{
 770        return 0;
 771}
 772
 773static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 774{
 775        return pte;
 776}
 777
 778static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
 779{
 780        return pmd;
 781}
 782
 783static inline int pmd_swp_soft_dirty(pmd_t pmd)
 784{
 785        return 0;
 786}
 787
 788static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
 789{
 790        return pmd;
 791}
 792#endif
 793
 794#ifndef __HAVE_PFNMAP_TRACKING
 795/*
 796 * Interfaces that can be used by architecture code to keep track of
 797 * memory type of pfn mappings specified by the remap_pfn_range,
 798 * vmf_insert_pfn.
 799 */
 800
 801/*
 802 * track_pfn_remap is called when a _new_ pfn mapping is being established
 803 * by remap_pfn_range() for physical range indicated by pfn and size.
 804 */
 805static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 806                                  unsigned long pfn, unsigned long addr,
 807                                  unsigned long size)
 808{
 809        return 0;
 810}
 811
 812/*
 813 * track_pfn_insert is called when a _new_ single pfn is established
 814 * by vmf_insert_pfn().
 815 */
 816static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 817                                    pfn_t pfn)
 818{
 819}
 820
 821/*
 822 * track_pfn_copy is called when vma that is covering the pfnmap gets
 823 * copied through copy_page_range().
 824 */
 825static inline int track_pfn_copy(struct vm_area_struct *vma)
 826{
 827        return 0;
 828}
 829
 830/*
 831 * untrack_pfn is called while unmapping a pfnmap for a region.
 832 * untrack can be called for a specific region indicated by pfn and size or
 833 * can be for the entire vma (in which case pfn, size are zero).
 834 */
 835static inline void untrack_pfn(struct vm_area_struct *vma,
 836                               unsigned long pfn, unsigned long size)
 837{
 838}
 839
 840/*
 841 * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
 842 */
 843static inline void untrack_pfn_moved(struct vm_area_struct *vma)
 844{
 845}
 846#else
 847extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 848                           unsigned long pfn, unsigned long addr,
 849                           unsigned long size);
 850extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 851                             pfn_t pfn);
 852extern int track_pfn_copy(struct vm_area_struct *vma);
 853extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 854                        unsigned long size);
 855extern void untrack_pfn_moved(struct vm_area_struct *vma);
 856#endif
 857
 858#ifdef __HAVE_COLOR_ZERO_PAGE
 859static inline int is_zero_pfn(unsigned long pfn)
 860{
 861        extern unsigned long zero_pfn;
 862        unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 863        return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 864}
 865
 866#define my_zero_pfn(addr)       page_to_pfn(ZERO_PAGE(addr))
 867
 868#else
 869static inline int is_zero_pfn(unsigned long pfn)
 870{
 871        extern unsigned long zero_pfn;
 872        return pfn == zero_pfn;
 873}
 874
 875static inline unsigned long my_zero_pfn(unsigned long addr)
 876{
 877        extern unsigned long zero_pfn;
 878        return zero_pfn;
 879}
 880#endif
 881
 882#ifdef CONFIG_MMU
 883
 884#ifndef CONFIG_TRANSPARENT_HUGEPAGE
 885static inline int pmd_trans_huge(pmd_t pmd)
 886{
 887        return 0;
 888}
 889#ifndef pmd_write
 890static inline int pmd_write(pmd_t pmd)
 891{
 892        BUG();
 893        return 0;
 894}
 895#endif /* pmd_write */
 896#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 897
 898#ifndef pud_write
 899static inline int pud_write(pud_t pud)
 900{
 901        BUG();
 902        return 0;
 903}
 904#endif /* pud_write */
 905
 906#if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 907        (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 908         !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 909static inline int pud_trans_huge(pud_t pud)
 910{
 911        return 0;
 912}
 913#endif
 914
 915#ifndef pmd_read_atomic
 916static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 917{
 918        /*
 919         * Depend on compiler for an atomic pmd read. NOTE: this is
 920         * only going to work, if the pmdval_t isn't larger than
 921         * an unsigned long.
 922         */
 923        return *pmdp;
 924}
 925#endif
 926
 927#ifndef arch_needs_pgtable_deposit
 928#define arch_needs_pgtable_deposit() (false)
 929#endif
 930/*
 931 * This function is meant to be used by sites walking pagetables with
 932 * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 933 * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 934 * into a null pmd and the transhuge page fault can convert a null pmd
 935 * into an hugepmd or into a regular pmd (if the hugepage allocation
 936 * fails). While holding the mmap_sem in read mode the pmd becomes
 937 * stable and stops changing under us only if it's not null and not a
 938 * transhuge pmd. When those races occurs and this function makes a
 939 * difference vs the standard pmd_none_or_clear_bad, the result is
 940 * undefined so behaving like if the pmd was none is safe (because it
 941 * can return none anyway). The compiler level barrier() is critically
 942 * important to compute the two checks atomically on the same pmdval.
 943 *
 944 * For 32bit kernels with a 64bit large pmd_t this automatically takes
 945 * care of reading the pmd atomically to avoid SMP race conditions
 946 * against pmd_populate() when the mmap_sem is hold for reading by the
 947 * caller (a special atomic read not done by "gcc" as in the generic
 948 * version above, is also needed when THP is disabled because the page
 949 * fault can populate the pmd from under us).
 950 */
 951static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 952{
 953        pmd_t pmdval = pmd_read_atomic(pmd);
 954        /*
 955         * The barrier will stabilize the pmdval in a register or on
 956         * the stack so that it will stop changing under the code.
 957         *
 958         * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 959         * pmd_read_atomic is allowed to return a not atomic pmdval
 960         * (for example pointing to an hugepage that has never been
 961         * mapped in the pmd). The below checks will only care about
 962         * the low part of the pmd with 32bit PAE x86 anyway, with the
 963         * exception of pmd_none(). So the important thing is that if
 964         * the low part of the pmd is found null, the high part will
 965         * be also null or the pmd_none() check below would be
 966         * confused.
 967         */
 968#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 969        barrier();
 970#endif
 971        /*
 972         * !pmd_present() checks for pmd migration entries
 973         *
 974         * The complete check uses is_pmd_migration_entry() in linux/swapops.h
 975         * But using that requires moving current function and pmd_trans_unstable()
 976         * to linux/swapops.h to resovle dependency, which is too much code move.
 977         *
 978         * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
 979         * because !pmd_present() pages can only be under migration not swapped
 980         * out.
 981         *
 982         * pmd_none() is preseved for future condition checks on pmd migration
 983         * entries and not confusing with this function name, although it is
 984         * redundant with !pmd_present().
 985         */
 986        if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
 987                (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
 988                return 1;
 989        if (unlikely(pmd_bad(pmdval))) {
 990                pmd_clear_bad(pmd);
 991                return 1;
 992        }
 993        return 0;
 994}
 995
 996/*
 997 * This is a noop if Transparent Hugepage Support is not built into
 998 * the kernel. Otherwise it is equivalent to
 999 * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
1000 * places that already verified the pmd is not none and they want to
1001 * walk ptes while holding the mmap sem in read mode (write mode don't
1002 * need this). If THP is not enabled, the pmd can't go away under the
1003 * code even if MADV_DONTNEED runs, but if THP is enabled we need to
1004 * run a pmd_trans_unstable before walking the ptes after
1005 * split_huge_pmd returns (because it may have run when the pmd become
1006 * null, but then a page fault can map in a THP and not a regular page).
1007 */
1008static inline int pmd_trans_unstable(pmd_t *pmd)
1009{
1010#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1011        return pmd_none_or_trans_huge_or_clear_bad(pmd);
1012#else
1013        return 0;
1014#endif
1015}
1016
1017#ifndef CONFIG_NUMA_BALANCING
1018/*
1019 * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
1020 * the only case the kernel cares is for NUMA balancing and is only ever set
1021 * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
1022 * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
1023 * is the responsibility of the caller to distinguish between PROT_NONE
1024 * protections and NUMA hinting fault protections.
1025 */
1026static inline int pte_protnone(pte_t pte)
1027{
1028        return 0;
1029}
1030
1031static inline int pmd_protnone(pmd_t pmd)
1032{
1033        return 0;
1034}
1035#endif /* CONFIG_NUMA_BALANCING */
1036
1037#endif /* CONFIG_MMU */
1038
1039#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
1040
1041#ifndef __PAGETABLE_P4D_FOLDED
1042int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
1043int p4d_clear_huge(p4d_t *p4d);
1044#else
1045static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1046{
1047        return 0;
1048}
1049static inline int p4d_clear_huge(p4d_t *p4d)
1050{
1051        return 0;
1052}
1053#endif /* !__PAGETABLE_P4D_FOLDED */
1054
1055int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
1056int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
1057int pud_clear_huge(pud_t *pud);
1058int pmd_clear_huge(pmd_t *pmd);
1059int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
1060int pud_free_pmd_page(pud_t *pud, unsigned long addr);
1061int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
1062#else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
1063static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1064{
1065        return 0;
1066}
1067static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
1068{
1069        return 0;
1070}
1071static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
1072{
1073        return 0;
1074}
1075static inline int p4d_clear_huge(p4d_t *p4d)
1076{
1077        return 0;
1078}
1079static inline int pud_clear_huge(pud_t *pud)
1080{
1081        return 0;
1082}
1083static inline int pmd_clear_huge(pmd_t *pmd)
1084{
1085        return 0;
1086}
1087static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1088{
1089        return 0;
1090}
1091static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
1092{
1093        return 0;
1094}
1095static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
1096{
1097        return 0;
1098}
1099#endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
1100
1101#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
1102#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1103/*
1104 * ARCHes with special requirements for evicting THP backing TLB entries can
1105 * implement this. Otherwise also, it can help optimize normal TLB flush in
1106 * THP regime. stock flush_tlb_range() typically has optimization to nuke the
1107 * entire TLB TLB if flush span is greater than a threshold, which will
1108 * likely be true for a single huge page. Thus a single thp flush will
1109 * invalidate the entire TLB which is not desitable.
1110 * e.g. see arch/arc: flush_pmd_tlb_range
1111 */
1112#define flush_pmd_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1113#define flush_pud_tlb_range(vma, addr, end)     flush_tlb_range(vma, addr, end)
1114#else
1115#define flush_pmd_tlb_range(vma, addr, end)     BUILD_BUG()
1116#define flush_pud_tlb_range(vma, addr, end)     BUILD_BUG()
1117#endif
1118#endif
1119
1120struct file;
1121int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
1122                        unsigned long size, pgprot_t *vma_prot);
1123
1124#ifndef CONFIG_X86_ESPFIX64
1125static inline void init_espfix_bsp(void) { }
1126#endif
1127
1128extern void __init pgtable_cache_init(void);
1129
1130#ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
1131static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
1132{
1133        return true;
1134}
1135
1136static inline bool arch_has_pfn_modify_check(void)
1137{
1138        return false;
1139}
1140#endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
1141
1142/*
1143 * Architecture PAGE_KERNEL_* fallbacks
1144 *
1145 * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
1146 * because they really don't support them, or the port needs to be updated to
1147 * reflect the required functionality. Below are a set of relatively safe
1148 * fallbacks, as best effort, which we can count on in lieu of the architectures
1149 * not defining them on their own yet.
1150 */
1151
1152#ifndef PAGE_KERNEL_RO
1153# define PAGE_KERNEL_RO PAGE_KERNEL
1154#endif
1155
1156#ifndef PAGE_KERNEL_EXEC
1157# define PAGE_KERNEL_EXEC PAGE_KERNEL
1158#endif
1159
1160#endif /* !__ASSEMBLY__ */
1161
1162#ifndef io_remap_pfn_range
1163#define io_remap_pfn_range remap_pfn_range
1164#endif
1165
1166#ifndef has_transparent_hugepage
1167#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1168#define has_transparent_hugepage() 1
1169#else
1170#define has_transparent_hugepage() 0
1171#endif
1172#endif
1173
1174/*
1175 * On some architectures it depends on the mm if the p4d/pud or pmd
1176 * layer of the page table hierarchy is folded or not.
1177 */
1178#ifndef mm_p4d_folded
1179#define mm_p4d_folded(mm)       __is_defined(__PAGETABLE_P4D_FOLDED)
1180#endif
1181
1182#ifndef mm_pud_folded
1183#define mm_pud_folded(mm)       __is_defined(__PAGETABLE_PUD_FOLDED)
1184#endif
1185
1186#ifndef mm_pmd_folded
1187#define mm_pmd_folded(mm)       __is_defined(__PAGETABLE_PMD_FOLDED)
1188#endif
1189
1190#endif /* _ASM_GENERIC_PGTABLE_H */
1191