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