pgtable.h 22 KB

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  1. #ifndef _ASM_GENERIC_PGTABLE_H
  2. #define _ASM_GENERIC_PGTABLE_H
  3. #ifndef __ASSEMBLY__
  4. #ifdef CONFIG_MMU
  5. #include <linux/mm_types.h>
  6. #include <linux/bug.h>
  7. /*
  8. * On almost all architectures and configurations, 0 can be used as the
  9. * upper ceiling to free_pgtables(): on many architectures it has the same
  10. * effect as using TASK_SIZE. However, there is one configuration which
  11. * must impose a more careful limit, to avoid freeing kernel pgtables.
  12. */
  13. #ifndef USER_PGTABLES_CEILING
  14. #define USER_PGTABLES_CEILING 0UL
  15. #endif
  16. #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  17. extern int ptep_set_access_flags(struct vm_area_struct *vma,
  18. unsigned long address, pte_t *ptep,
  19. pte_t entry, int dirty);
  20. #endif
  21. #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  22. extern int pmdp_set_access_flags(struct vm_area_struct *vma,
  23. unsigned long address, pmd_t *pmdp,
  24. pmd_t entry, int dirty);
  25. #endif
  26. #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
  27. static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
  28. unsigned long address,
  29. pte_t *ptep)
  30. {
  31. pte_t pte = *ptep;
  32. int r = 1;
  33. if (!pte_young(pte))
  34. r = 0;
  35. else
  36. set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
  37. return r;
  38. }
  39. #endif
  40. #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
  41. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  42. static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  43. unsigned long address,
  44. pmd_t *pmdp)
  45. {
  46. pmd_t pmd = *pmdp;
  47. int r = 1;
  48. if (!pmd_young(pmd))
  49. r = 0;
  50. else
  51. set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
  52. return r;
  53. }
  54. #else /* CONFIG_TRANSPARENT_HUGEPAGE */
  55. static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
  56. unsigned long address,
  57. pmd_t *pmdp)
  58. {
  59. BUG();
  60. return 0;
  61. }
  62. #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  63. #endif
  64. #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  65. int ptep_clear_flush_young(struct vm_area_struct *vma,
  66. unsigned long address, pte_t *ptep);
  67. #endif
  68. #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
  69. int pmdp_clear_flush_young(struct vm_area_struct *vma,
  70. unsigned long address, pmd_t *pmdp);
  71. #endif
  72. #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
  73. static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
  74. unsigned long address,
  75. pte_t *ptep)
  76. {
  77. pte_t pte = *ptep;
  78. pte_clear(mm, address, ptep);
  79. return pte;
  80. }
  81. #endif
  82. #ifndef __HAVE_ARCH_PMDP_GET_AND_CLEAR
  83. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  84. static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
  85. unsigned long address,
  86. pmd_t *pmdp)
  87. {
  88. pmd_t pmd = *pmdp;
  89. pmd_clear(pmdp);
  90. return pmd;
  91. }
  92. #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  93. #endif
  94. #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
  95. static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
  96. unsigned long address, pte_t *ptep,
  97. int full)
  98. {
  99. pte_t pte;
  100. pte = ptep_get_and_clear(mm, address, ptep);
  101. return pte;
  102. }
  103. #endif
  104. /*
  105. * Some architectures may be able to avoid expensive synchronization
  106. * primitives when modifications are made to PTE's which are already
  107. * not present, or in the process of an address space destruction.
  108. */
  109. #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
  110. static inline void pte_clear_not_present_full(struct mm_struct *mm,
  111. unsigned long address,
  112. pte_t *ptep,
  113. int full)
  114. {
  115. pte_clear(mm, address, ptep);
  116. }
  117. #endif
  118. #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  119. extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
  120. unsigned long address,
  121. pte_t *ptep);
  122. #endif
  123. #ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
  124. extern pmd_t pmdp_clear_flush(struct vm_area_struct *vma,
  125. unsigned long address,
  126. pmd_t *pmdp);
  127. #endif
  128. #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
  129. struct mm_struct;
  130. static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
  131. {
  132. pte_t old_pte = *ptep;
  133. set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
  134. }
  135. #endif
  136. #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
  137. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  138. static inline void pmdp_set_wrprotect(struct mm_struct *mm,
  139. unsigned long address, pmd_t *pmdp)
  140. {
  141. pmd_t old_pmd = *pmdp;
  142. set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
  143. }
  144. #else /* CONFIG_TRANSPARENT_HUGEPAGE */
  145. static inline void pmdp_set_wrprotect(struct mm_struct *mm,
  146. unsigned long address, pmd_t *pmdp)
  147. {
  148. BUG();
  149. }
  150. #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  151. #endif
  152. #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
  153. extern void pmdp_splitting_flush(struct vm_area_struct *vma,
  154. unsigned long address, pmd_t *pmdp);
  155. #endif
  156. #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
  157. extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
  158. pgtable_t pgtable);
  159. #endif
  160. #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
  161. extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
  162. #endif
  163. #ifndef __HAVE_ARCH_PMDP_INVALIDATE
  164. extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
  165. pmd_t *pmdp);
  166. #endif
  167. #ifndef __HAVE_ARCH_PTE_SAME
  168. static inline int pte_same(pte_t pte_a, pte_t pte_b)
  169. {
  170. return pte_val(pte_a) == pte_val(pte_b);
  171. }
  172. #endif
  173. #ifndef __HAVE_ARCH_PTE_UNUSED
  174. /*
  175. * Some architectures provide facilities to virtualization guests
  176. * so that they can flag allocated pages as unused. This allows the
  177. * host to transparently reclaim unused pages. This function returns
  178. * whether the pte's page is unused.
  179. */
  180. static inline int pte_unused(pte_t pte)
  181. {
  182. return 0;
  183. }
  184. #endif
  185. #ifndef __HAVE_ARCH_PMD_SAME
  186. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  187. static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
  188. {
  189. return pmd_val(pmd_a) == pmd_val(pmd_b);
  190. }
  191. #else /* CONFIG_TRANSPARENT_HUGEPAGE */
  192. static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
  193. {
  194. BUG();
  195. return 0;
  196. }
  197. #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  198. #endif
  199. #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
  200. #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
  201. #endif
  202. #ifndef __HAVE_ARCH_MOVE_PTE
  203. #define move_pte(pte, prot, old_addr, new_addr) (pte)
  204. #endif
  205. #ifndef pte_accessible
  206. # define pte_accessible(mm, pte) ((void)(pte), 1)
  207. #endif
  208. #ifndef pte_present_nonuma
  209. #define pte_present_nonuma(pte) pte_present(pte)
  210. #endif
  211. #ifndef flush_tlb_fix_spurious_fault
  212. #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
  213. #endif
  214. #ifndef pgprot_noncached
  215. #define pgprot_noncached(prot) (prot)
  216. #endif
  217. #ifndef pgprot_writecombine
  218. #define pgprot_writecombine pgprot_noncached
  219. #endif
  220. #ifndef pgprot_device
  221. #define pgprot_device pgprot_noncached
  222. #endif
  223. #ifndef pgprot_modify
  224. #define pgprot_modify pgprot_modify
  225. static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
  226. {
  227. if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
  228. newprot = pgprot_noncached(newprot);
  229. if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
  230. newprot = pgprot_writecombine(newprot);
  231. if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
  232. newprot = pgprot_device(newprot);
  233. return newprot;
  234. }
  235. #endif
  236. /*
  237. * When walking page tables, get the address of the next boundary,
  238. * or the end address of the range if that comes earlier. Although no
  239. * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
  240. */
  241. #define pgd_addr_end(addr, end) \
  242. ({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
  243. (__boundary - 1 < (end) - 1)? __boundary: (end); \
  244. })
  245. #ifndef pud_addr_end
  246. #define pud_addr_end(addr, end) \
  247. ({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \
  248. (__boundary - 1 < (end) - 1)? __boundary: (end); \
  249. })
  250. #endif
  251. #ifndef pmd_addr_end
  252. #define pmd_addr_end(addr, end) \
  253. ({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \
  254. (__boundary - 1 < (end) - 1)? __boundary: (end); \
  255. })
  256. #endif
  257. /*
  258. * When walking page tables, we usually want to skip any p?d_none entries;
  259. * and any p?d_bad entries - reporting the error before resetting to none.
  260. * Do the tests inline, but report and clear the bad entry in mm/memory.c.
  261. */
  262. void pgd_clear_bad(pgd_t *);
  263. void pud_clear_bad(pud_t *);
  264. void pmd_clear_bad(pmd_t *);
  265. static inline int pgd_none_or_clear_bad(pgd_t *pgd)
  266. {
  267. if (pgd_none(*pgd))
  268. return 1;
  269. if (unlikely(pgd_bad(*pgd))) {
  270. pgd_clear_bad(pgd);
  271. return 1;
  272. }
  273. return 0;
  274. }
  275. static inline int pud_none_or_clear_bad(pud_t *pud)
  276. {
  277. if (pud_none(*pud))
  278. return 1;
  279. if (unlikely(pud_bad(*pud))) {
  280. pud_clear_bad(pud);
  281. return 1;
  282. }
  283. return 0;
  284. }
  285. static inline int pmd_none_or_clear_bad(pmd_t *pmd)
  286. {
  287. if (pmd_none(*pmd))
  288. return 1;
  289. if (unlikely(pmd_bad(*pmd))) {
  290. pmd_clear_bad(pmd);
  291. return 1;
  292. }
  293. return 0;
  294. }
  295. static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
  296. unsigned long addr,
  297. pte_t *ptep)
  298. {
  299. /*
  300. * Get the current pte state, but zero it out to make it
  301. * non-present, preventing the hardware from asynchronously
  302. * updating it.
  303. */
  304. return ptep_get_and_clear(mm, addr, ptep);
  305. }
  306. static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
  307. unsigned long addr,
  308. pte_t *ptep, pte_t pte)
  309. {
  310. /*
  311. * The pte is non-present, so there's no hardware state to
  312. * preserve.
  313. */
  314. set_pte_at(mm, addr, ptep, pte);
  315. }
  316. #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
  317. /*
  318. * Start a pte protection read-modify-write transaction, which
  319. * protects against asynchronous hardware modifications to the pte.
  320. * The intention is not to prevent the hardware from making pte
  321. * updates, but to prevent any updates it may make from being lost.
  322. *
  323. * This does not protect against other software modifications of the
  324. * pte; the appropriate pte lock must be held over the transation.
  325. *
  326. * Note that this interface is intended to be batchable, meaning that
  327. * ptep_modify_prot_commit may not actually update the pte, but merely
  328. * queue the update to be done at some later time. The update must be
  329. * actually committed before the pte lock is released, however.
  330. */
  331. static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
  332. unsigned long addr,
  333. pte_t *ptep)
  334. {
  335. return __ptep_modify_prot_start(mm, addr, ptep);
  336. }
  337. /*
  338. * Commit an update to a pte, leaving any hardware-controlled bits in
  339. * the PTE unmodified.
  340. */
  341. static inline void ptep_modify_prot_commit(struct mm_struct *mm,
  342. unsigned long addr,
  343. pte_t *ptep, pte_t pte)
  344. {
  345. __ptep_modify_prot_commit(mm, addr, ptep, pte);
  346. }
  347. #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
  348. #endif /* CONFIG_MMU */
  349. /*
  350. * A facility to provide lazy MMU batching. This allows PTE updates and
  351. * page invalidations to be delayed until a call to leave lazy MMU mode
  352. * is issued. Some architectures may benefit from doing this, and it is
  353. * beneficial for both shadow and direct mode hypervisors, which may batch
  354. * the PTE updates which happen during this window. Note that using this
  355. * interface requires that read hazards be removed from the code. A read
  356. * hazard could result in the direct mode hypervisor case, since the actual
  357. * write to the page tables may not yet have taken place, so reads though
  358. * a raw PTE pointer after it has been modified are not guaranteed to be
  359. * up to date. This mode can only be entered and left under the protection of
  360. * the page table locks for all page tables which may be modified. In the UP
  361. * case, this is required so that preemption is disabled, and in the SMP case,
  362. * it must synchronize the delayed page table writes properly on other CPUs.
  363. */
  364. #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
  365. #define arch_enter_lazy_mmu_mode() do {} while (0)
  366. #define arch_leave_lazy_mmu_mode() do {} while (0)
  367. #define arch_flush_lazy_mmu_mode() do {} while (0)
  368. #endif
  369. /*
  370. * A facility to provide batching of the reload of page tables and
  371. * other process state with the actual context switch code for
  372. * paravirtualized guests. By convention, only one of the batched
  373. * update (lazy) modes (CPU, MMU) should be active at any given time,
  374. * entry should never be nested, and entry and exits should always be
  375. * paired. This is for sanity of maintaining and reasoning about the
  376. * kernel code. In this case, the exit (end of the context switch) is
  377. * in architecture-specific code, and so doesn't need a generic
  378. * definition.
  379. */
  380. #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
  381. #define arch_start_context_switch(prev) do {} while (0)
  382. #endif
  383. #ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
  384. static inline int pte_soft_dirty(pte_t pte)
  385. {
  386. return 0;
  387. }
  388. static inline int pmd_soft_dirty(pmd_t pmd)
  389. {
  390. return 0;
  391. }
  392. static inline pte_t pte_mksoft_dirty(pte_t pte)
  393. {
  394. return pte;
  395. }
  396. static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
  397. {
  398. return pmd;
  399. }
  400. static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
  401. {
  402. return pte;
  403. }
  404. static inline int pte_swp_soft_dirty(pte_t pte)
  405. {
  406. return 0;
  407. }
  408. static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
  409. {
  410. return pte;
  411. }
  412. static inline pte_t pte_file_clear_soft_dirty(pte_t pte)
  413. {
  414. return pte;
  415. }
  416. static inline pte_t pte_file_mksoft_dirty(pte_t pte)
  417. {
  418. return pte;
  419. }
  420. static inline int pte_file_soft_dirty(pte_t pte)
  421. {
  422. return 0;
  423. }
  424. #endif
  425. #ifndef __HAVE_PFNMAP_TRACKING
  426. /*
  427. * Interfaces that can be used by architecture code to keep track of
  428. * memory type of pfn mappings specified by the remap_pfn_range,
  429. * vm_insert_pfn.
  430. */
  431. /*
  432. * track_pfn_remap is called when a _new_ pfn mapping is being established
  433. * by remap_pfn_range() for physical range indicated by pfn and size.
  434. */
  435. static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
  436. unsigned long pfn, unsigned long addr,
  437. unsigned long size)
  438. {
  439. return 0;
  440. }
  441. /*
  442. * track_pfn_insert is called when a _new_ single pfn is established
  443. * by vm_insert_pfn().
  444. */
  445. static inline int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
  446. unsigned long pfn)
  447. {
  448. return 0;
  449. }
  450. /*
  451. * track_pfn_copy is called when vma that is covering the pfnmap gets
  452. * copied through copy_page_range().
  453. */
  454. static inline int track_pfn_copy(struct vm_area_struct *vma)
  455. {
  456. return 0;
  457. }
  458. /*
  459. * untrack_pfn_vma is called while unmapping a pfnmap for a region.
  460. * untrack can be called for a specific region indicated by pfn and size or
  461. * can be for the entire vma (in which case pfn, size are zero).
  462. */
  463. static inline void untrack_pfn(struct vm_area_struct *vma,
  464. unsigned long pfn, unsigned long size)
  465. {
  466. }
  467. #else
  468. extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
  469. unsigned long pfn, unsigned long addr,
  470. unsigned long size);
  471. extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
  472. unsigned long pfn);
  473. extern int track_pfn_copy(struct vm_area_struct *vma);
  474. extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
  475. unsigned long size);
  476. #endif
  477. #ifdef __HAVE_COLOR_ZERO_PAGE
  478. static inline int is_zero_pfn(unsigned long pfn)
  479. {
  480. extern unsigned long zero_pfn;
  481. unsigned long offset_from_zero_pfn = pfn - zero_pfn;
  482. return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
  483. }
  484. #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr))
  485. #else
  486. static inline int is_zero_pfn(unsigned long pfn)
  487. {
  488. extern unsigned long zero_pfn;
  489. return pfn == zero_pfn;
  490. }
  491. static inline unsigned long my_zero_pfn(unsigned long addr)
  492. {
  493. extern unsigned long zero_pfn;
  494. return zero_pfn;
  495. }
  496. #endif
  497. #ifdef CONFIG_MMU
  498. #ifndef CONFIG_TRANSPARENT_HUGEPAGE
  499. static inline int pmd_trans_huge(pmd_t pmd)
  500. {
  501. return 0;
  502. }
  503. static inline int pmd_trans_splitting(pmd_t pmd)
  504. {
  505. return 0;
  506. }
  507. #ifndef __HAVE_ARCH_PMD_WRITE
  508. static inline int pmd_write(pmd_t pmd)
  509. {
  510. BUG();
  511. return 0;
  512. }
  513. #endif /* __HAVE_ARCH_PMD_WRITE */
  514. #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  515. #ifndef pmd_read_atomic
  516. static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
  517. {
  518. /*
  519. * Depend on compiler for an atomic pmd read. NOTE: this is
  520. * only going to work, if the pmdval_t isn't larger than
  521. * an unsigned long.
  522. */
  523. return *pmdp;
  524. }
  525. #endif
  526. #ifndef pmd_move_must_withdraw
  527. static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
  528. spinlock_t *old_pmd_ptl)
  529. {
  530. /*
  531. * With split pmd lock we also need to move preallocated
  532. * PTE page table if new_pmd is on different PMD page table.
  533. */
  534. return new_pmd_ptl != old_pmd_ptl;
  535. }
  536. #endif
  537. /*
  538. * This function is meant to be used by sites walking pagetables with
  539. * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
  540. * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
  541. * into a null pmd and the transhuge page fault can convert a null pmd
  542. * into an hugepmd or into a regular pmd (if the hugepage allocation
  543. * fails). While holding the mmap_sem in read mode the pmd becomes
  544. * stable and stops changing under us only if it's not null and not a
  545. * transhuge pmd. When those races occurs and this function makes a
  546. * difference vs the standard pmd_none_or_clear_bad, the result is
  547. * undefined so behaving like if the pmd was none is safe (because it
  548. * can return none anyway). The compiler level barrier() is critically
  549. * important to compute the two checks atomically on the same pmdval.
  550. *
  551. * For 32bit kernels with a 64bit large pmd_t this automatically takes
  552. * care of reading the pmd atomically to avoid SMP race conditions
  553. * against pmd_populate() when the mmap_sem is hold for reading by the
  554. * caller (a special atomic read not done by "gcc" as in the generic
  555. * version above, is also needed when THP is disabled because the page
  556. * fault can populate the pmd from under us).
  557. */
  558. static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
  559. {
  560. pmd_t pmdval = pmd_read_atomic(pmd);
  561. /*
  562. * The barrier will stabilize the pmdval in a register or on
  563. * the stack so that it will stop changing under the code.
  564. *
  565. * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
  566. * pmd_read_atomic is allowed to return a not atomic pmdval
  567. * (for example pointing to an hugepage that has never been
  568. * mapped in the pmd). The below checks will only care about
  569. * the low part of the pmd with 32bit PAE x86 anyway, with the
  570. * exception of pmd_none(). So the important thing is that if
  571. * the low part of the pmd is found null, the high part will
  572. * be also null or the pmd_none() check below would be
  573. * confused.
  574. */
  575. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  576. barrier();
  577. #endif
  578. if (pmd_none(pmdval) || pmd_trans_huge(pmdval))
  579. return 1;
  580. if (unlikely(pmd_bad(pmdval))) {
  581. pmd_clear_bad(pmd);
  582. return 1;
  583. }
  584. return 0;
  585. }
  586. /*
  587. * This is a noop if Transparent Hugepage Support is not built into
  588. * the kernel. Otherwise it is equivalent to
  589. * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
  590. * places that already verified the pmd is not none and they want to
  591. * walk ptes while holding the mmap sem in read mode (write mode don't
  592. * need this). If THP is not enabled, the pmd can't go away under the
  593. * code even if MADV_DONTNEED runs, but if THP is enabled we need to
  594. * run a pmd_trans_unstable before walking the ptes after
  595. * split_huge_page_pmd returns (because it may have run when the pmd
  596. * become null, but then a page fault can map in a THP and not a
  597. * regular page).
  598. */
  599. static inline int pmd_trans_unstable(pmd_t *pmd)
  600. {
  601. #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  602. return pmd_none_or_trans_huge_or_clear_bad(pmd);
  603. #else
  604. return 0;
  605. #endif
  606. }
  607. #ifdef CONFIG_NUMA_BALANCING
  608. /*
  609. * _PAGE_NUMA distinguishes between an unmapped page table entry, an entry that
  610. * is protected for PROT_NONE and a NUMA hinting fault entry. If the
  611. * architecture defines __PAGE_PROTNONE then it should take that into account
  612. * but those that do not can rely on the fact that the NUMA hinting scanner
  613. * skips inaccessible VMAs.
  614. *
  615. * pte/pmd_present() returns true if pte/pmd_numa returns true. Page
  616. * fault triggers on those regions if pte/pmd_numa returns true
  617. * (because _PAGE_PRESENT is not set).
  618. */
  619. #ifndef pte_numa
  620. static inline int pte_numa(pte_t pte)
  621. {
  622. return ptenuma_flags(pte) == _PAGE_NUMA;
  623. }
  624. #endif
  625. #ifndef pmd_numa
  626. static inline int pmd_numa(pmd_t pmd)
  627. {
  628. return pmdnuma_flags(pmd) == _PAGE_NUMA;
  629. }
  630. #endif
  631. /*
  632. * pte/pmd_mknuma sets the _PAGE_ACCESSED bitflag automatically
  633. * because they're called by the NUMA hinting minor page fault. If we
  634. * wouldn't set the _PAGE_ACCESSED bitflag here, the TLB miss handler
  635. * would be forced to set it later while filling the TLB after we
  636. * return to userland. That would trigger a second write to memory
  637. * that we optimize away by setting _PAGE_ACCESSED here.
  638. */
  639. #ifndef pte_mknonnuma
  640. static inline pte_t pte_mknonnuma(pte_t pte)
  641. {
  642. pteval_t val = pte_val(pte);
  643. val &= ~_PAGE_NUMA;
  644. val |= (_PAGE_PRESENT|_PAGE_ACCESSED);
  645. return __pte(val);
  646. }
  647. #endif
  648. #ifndef pmd_mknonnuma
  649. static inline pmd_t pmd_mknonnuma(pmd_t pmd)
  650. {
  651. pmdval_t val = pmd_val(pmd);
  652. val &= ~_PAGE_NUMA;
  653. val |= (_PAGE_PRESENT|_PAGE_ACCESSED);
  654. return __pmd(val);
  655. }
  656. #endif
  657. #ifndef pte_mknuma
  658. static inline pte_t pte_mknuma(pte_t pte)
  659. {
  660. pteval_t val = pte_val(pte);
  661. VM_BUG_ON(!(val & _PAGE_PRESENT));
  662. val &= ~_PAGE_PRESENT;
  663. val |= _PAGE_NUMA;
  664. return __pte(val);
  665. }
  666. #endif
  667. #ifndef ptep_set_numa
  668. static inline void ptep_set_numa(struct mm_struct *mm, unsigned long addr,
  669. pte_t *ptep)
  670. {
  671. pte_t ptent = *ptep;
  672. ptent = pte_mknuma(ptent);
  673. set_pte_at(mm, addr, ptep, ptent);
  674. return;
  675. }
  676. #endif
  677. #ifndef pmd_mknuma
  678. static inline pmd_t pmd_mknuma(pmd_t pmd)
  679. {
  680. pmdval_t val = pmd_val(pmd);
  681. val &= ~_PAGE_PRESENT;
  682. val |= _PAGE_NUMA;
  683. return __pmd(val);
  684. }
  685. #endif
  686. #ifndef pmdp_set_numa
  687. static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr,
  688. pmd_t *pmdp)
  689. {
  690. pmd_t pmd = *pmdp;
  691. pmd = pmd_mknuma(pmd);
  692. set_pmd_at(mm, addr, pmdp, pmd);
  693. return;
  694. }
  695. #endif
  696. #else
  697. static inline int pmd_numa(pmd_t pmd)
  698. {
  699. return 0;
  700. }
  701. static inline int pte_numa(pte_t pte)
  702. {
  703. return 0;
  704. }
  705. static inline pte_t pte_mknonnuma(pte_t pte)
  706. {
  707. return pte;
  708. }
  709. static inline pmd_t pmd_mknonnuma(pmd_t pmd)
  710. {
  711. return pmd;
  712. }
  713. static inline pte_t pte_mknuma(pte_t pte)
  714. {
  715. return pte;
  716. }
  717. static inline void ptep_set_numa(struct mm_struct *mm, unsigned long addr,
  718. pte_t *ptep)
  719. {
  720. return;
  721. }
  722. static inline pmd_t pmd_mknuma(pmd_t pmd)
  723. {
  724. return pmd;
  725. }
  726. static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr,
  727. pmd_t *pmdp)
  728. {
  729. return ;
  730. }
  731. #endif /* CONFIG_NUMA_BALANCING */
  732. #endif /* CONFIG_MMU */
  733. #endif /* !__ASSEMBLY__ */
  734. #ifndef io_remap_pfn_range
  735. #define io_remap_pfn_range remap_pfn_range
  736. #endif
  737. #endif /* _ASM_GENERIC_PGTABLE_H */