Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef _LINUX_PGTABLE_H
3 : #define _LINUX_PGTABLE_H
4 :
5 : #include <linux/pfn.h>
6 : #include <asm/pgtable.h>
7 :
8 : #ifndef __ASSEMBLY__
9 : #ifdef CONFIG_MMU
10 :
11 : #include <linux/mm_types.h>
12 : #include <linux/bug.h>
13 : #include <linux/errno.h>
14 : #include <asm-generic/pgtable_uffd.h>
15 : #include <linux/page_table_check.h>
16 :
17 : #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \
18 : defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS
19 : #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED
20 : #endif
21 :
22 : /*
23 : * On almost all architectures and configurations, 0 can be used as the
24 : * upper ceiling to free_pgtables(): on many architectures it has the same
25 : * effect as using TASK_SIZE. However, there is one configuration which
26 : * must impose a more careful limit, to avoid freeing kernel pgtables.
27 : */
28 : #ifndef USER_PGTABLES_CEILING
29 : #define USER_PGTABLES_CEILING 0UL
30 : #endif
31 :
32 : /*
33 : * This defines the first usable user address. Platforms
34 : * can override its value with custom FIRST_USER_ADDRESS
35 : * defined in their respective <asm/pgtable.h>.
36 : */
37 : #ifndef FIRST_USER_ADDRESS
38 : #define FIRST_USER_ADDRESS 0UL
39 : #endif
40 :
41 : /*
42 : * This defines the generic helper for accessing PMD page
43 : * table page. Although platforms can still override this
44 : * via their respective <asm/pgtable.h>.
45 : */
46 : #ifndef pmd_pgtable
47 : #define pmd_pgtable(pmd) pmd_page(pmd)
48 : #endif
49 :
50 : /*
51 : * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
52 : *
53 : * The pXx_index() functions return the index of the entry in the page
54 : * table page which would control the given virtual address
55 : *
56 : * As these functions may be used by the same code for different levels of
57 : * the page table folding, they are always available, regardless of
58 : * CONFIG_PGTABLE_LEVELS value. For the folded levels they simply return 0
59 : * because in such cases PTRS_PER_PxD equals 1.
60 : */
61 :
62 : static inline unsigned long pte_index(unsigned long address)
63 : {
64 127962 : return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
65 : }
66 : #define pte_index pte_index
67 :
68 : #ifndef pmd_index
69 : static inline unsigned long pmd_index(unsigned long address)
70 : {
71 127807 : return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
72 : }
73 : #define pmd_index pmd_index
74 : #endif
75 :
76 : #ifndef pud_index
77 : static inline unsigned long pud_index(unsigned long address)
78 : {
79 : return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1);
80 : }
81 : #define pud_index pud_index
82 : #endif
83 :
84 : #ifndef pgd_index
85 : /* Must be a compile-time constant, so implement it as a macro */
86 : #define pgd_index(a) (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
87 : #endif
88 :
89 : #ifndef pte_offset_kernel
90 : static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address)
91 : {
92 383887 : return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address);
93 : }
94 : #define pte_offset_kernel pte_offset_kernel
95 : #endif
96 :
97 : #if defined(CONFIG_HIGHPTE)
98 : #define pte_offset_map(dir, address) \
99 : ((pte_t *)kmap_atomic(pmd_page(*(dir))) + \
100 : pte_index((address)))
101 : #define pte_unmap(pte) kunmap_atomic((pte))
102 : #else
103 : #define pte_offset_map(dir, address) pte_offset_kernel((dir), (address))
104 : #define pte_unmap(pte) ((void)(pte)) /* NOP */
105 : #endif
106 :
107 : /* Find an entry in the second-level page table.. */
108 : #ifndef pmd_offset
109 : static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
110 : {
111 383420 : return pud_pgtable(*pud) + pmd_index(address);
112 : }
113 : #define pmd_offset pmd_offset
114 : #endif
115 :
116 : #ifndef pud_offset
117 : static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
118 : {
119 : return p4d_pgtable(*p4d) + pud_index(address);
120 : }
121 : #define pud_offset pud_offset
122 : #endif
123 :
124 : static inline pgd_t *pgd_offset_pgd(pgd_t *pgd, unsigned long address)
125 : {
126 127805 : return (pgd + pgd_index(address));
127 : };
128 :
129 : /*
130 : * a shortcut to get a pgd_t in a given mm
131 : */
132 : #ifndef pgd_offset
133 : #define pgd_offset(mm, address) pgd_offset_pgd((mm)->pgd, (address))
134 : #endif
135 :
136 : /*
137 : * a shortcut which implies the use of the kernel's pgd, instead
138 : * of a process's
139 : */
140 : #ifndef pgd_offset_k
141 : #define pgd_offset_k(address) pgd_offset(&init_mm, (address))
142 : #endif
143 :
144 : /*
145 : * In many cases it is known that a virtual address is mapped at PMD or PTE
146 : * level, so instead of traversing all the page table levels, we can get a
147 : * pointer to the PMD entry in user or kernel page table or translate a virtual
148 : * address to the pointer in the PTE in the kernel page tables with simple
149 : * helpers.
150 : */
151 : static inline pmd_t *pmd_off(struct mm_struct *mm, unsigned long va)
152 : {
153 0 : return pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, va), va), va), va);
154 : }
155 :
156 : static inline pmd_t *pmd_off_k(unsigned long va)
157 : {
158 : return pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va);
159 : }
160 :
161 : static inline pte_t *virt_to_kpte(unsigned long vaddr)
162 : {
163 : pmd_t *pmd = pmd_off_k(vaddr);
164 :
165 : return pmd_none(*pmd) ? NULL : pte_offset_kernel(pmd, vaddr);
166 : }
167 :
168 : #ifndef pmd_young
169 : static inline int pmd_young(pmd_t pmd)
170 : {
171 : return 0;
172 : }
173 : #endif
174 :
175 : #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
176 : extern int ptep_set_access_flags(struct vm_area_struct *vma,
177 : unsigned long address, pte_t *ptep,
178 : pte_t entry, int dirty);
179 : #endif
180 :
181 : #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
182 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
183 : extern int pmdp_set_access_flags(struct vm_area_struct *vma,
184 : unsigned long address, pmd_t *pmdp,
185 : pmd_t entry, int dirty);
186 : extern int pudp_set_access_flags(struct vm_area_struct *vma,
187 : unsigned long address, pud_t *pudp,
188 : pud_t entry, int dirty);
189 : #else
190 : static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
191 : unsigned long address, pmd_t *pmdp,
192 : pmd_t entry, int dirty)
193 : {
194 : BUILD_BUG();
195 : return 0;
196 : }
197 : static inline int pudp_set_access_flags(struct vm_area_struct *vma,
198 : unsigned long address, pud_t *pudp,
199 : pud_t entry, int dirty)
200 : {
201 : BUILD_BUG();
202 : return 0;
203 : }
204 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
205 : #endif
206 :
207 : #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
208 : static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
209 : unsigned long address,
210 : pte_t *ptep)
211 : {
212 0 : pte_t pte = *ptep;
213 0 : int r = 1;
214 0 : if (!pte_young(pte))
215 : r = 0;
216 : else
217 0 : set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
218 : return r;
219 : }
220 : #endif
221 :
222 : #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
223 : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
224 : static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
225 : unsigned long address,
226 : pmd_t *pmdp)
227 : {
228 : pmd_t pmd = *pmdp;
229 : int r = 1;
230 : if (!pmd_young(pmd))
231 : r = 0;
232 : else
233 : set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
234 : return r;
235 : }
236 : #else
237 : static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
238 : unsigned long address,
239 : pmd_t *pmdp)
240 : {
241 : BUILD_BUG();
242 : return 0;
243 : }
244 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */
245 : #endif
246 :
247 : #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
248 : int ptep_clear_flush_young(struct vm_area_struct *vma,
249 : unsigned long address, pte_t *ptep);
250 : #endif
251 :
252 : #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
253 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
254 : extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
255 : unsigned long address, pmd_t *pmdp);
256 : #else
257 : /*
258 : * Despite relevant to THP only, this API is called from generic rmap code
259 : * under PageTransHuge(), hence needs a dummy implementation for !THP
260 : */
261 : static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
262 : unsigned long address, pmd_t *pmdp)
263 : {
264 : BUILD_BUG();
265 : return 0;
266 : }
267 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
268 : #endif
269 :
270 : #ifndef arch_has_hw_nonleaf_pmd_young
271 : /*
272 : * Return whether the accessed bit in non-leaf PMD entries is supported on the
273 : * local CPU.
274 : */
275 : static inline bool arch_has_hw_nonleaf_pmd_young(void)
276 : {
277 : return IS_ENABLED(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG);
278 : }
279 : #endif
280 :
281 : #ifndef arch_has_hw_pte_young
282 : /*
283 : * Return whether the accessed bit is supported on the local CPU.
284 : *
285 : * This stub assumes accessing through an old PTE triggers a page fault.
286 : * Architectures that automatically set the access bit should overwrite it.
287 : */
288 : static inline bool arch_has_hw_pte_young(void)
289 : {
290 : return false;
291 : }
292 : #endif
293 :
294 : #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
295 : static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
296 : unsigned long address,
297 : pte_t *ptep)
298 : {
299 42734 : pte_t pte = *ptep;
300 42734 : pte_clear(mm, address, ptep);
301 42734 : page_table_check_pte_clear(mm, address, pte);
302 : return pte;
303 : }
304 : #endif
305 :
306 : static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
307 : pte_t *ptep)
308 : {
309 : ptep_get_and_clear(mm, addr, ptep);
310 : }
311 :
312 : #ifndef ptep_get
313 : static inline pte_t ptep_get(pte_t *ptep)
314 : {
315 : return READ_ONCE(*ptep);
316 : }
317 : #endif
318 :
319 : #ifndef pmdp_get
320 : static inline pmd_t pmdp_get(pmd_t *pmdp)
321 : {
322 0 : return READ_ONCE(*pmdp);
323 : }
324 : #endif
325 :
326 : #ifdef CONFIG_GUP_GET_PXX_LOW_HIGH
327 : /*
328 : * For walking the pagetables without holding any locks. Some architectures
329 : * (eg x86-32 PAE) cannot load the entries atomically without using expensive
330 : * instructions. We are guaranteed that a PTE will only either go from not
331 : * present to present, or present to not present -- it will not switch to a
332 : * completely different present page without a TLB flush inbetween; which we
333 : * are blocking by holding interrupts off.
334 : *
335 : * Setting ptes from not present to present goes:
336 : *
337 : * ptep->pte_high = h;
338 : * smp_wmb();
339 : * ptep->pte_low = l;
340 : *
341 : * And present to not present goes:
342 : *
343 : * ptep->pte_low = 0;
344 : * smp_wmb();
345 : * ptep->pte_high = 0;
346 : *
347 : * We must ensure here that the load of pte_low sees 'l' IFF pte_high sees 'h'.
348 : * We load pte_high *after* loading pte_low, which ensures we don't see an older
349 : * value of pte_high. *Then* we recheck pte_low, which ensures that we haven't
350 : * picked up a changed pte high. We might have gotten rubbish values from
351 : * pte_low and pte_high, but we are guaranteed that pte_low will not have the
352 : * present bit set *unless* it is 'l'. Because get_user_pages_fast() only
353 : * operates on present ptes we're safe.
354 : */
355 : static inline pte_t ptep_get_lockless(pte_t *ptep)
356 : {
357 : pte_t pte;
358 :
359 : do {
360 : pte.pte_low = ptep->pte_low;
361 : smp_rmb();
362 : pte.pte_high = ptep->pte_high;
363 : smp_rmb();
364 : } while (unlikely(pte.pte_low != ptep->pte_low));
365 :
366 : return pte;
367 : }
368 : #define ptep_get_lockless ptep_get_lockless
369 :
370 : #if CONFIG_PGTABLE_LEVELS > 2
371 : static inline pmd_t pmdp_get_lockless(pmd_t *pmdp)
372 : {
373 : pmd_t pmd;
374 :
375 : do {
376 : pmd.pmd_low = pmdp->pmd_low;
377 : smp_rmb();
378 : pmd.pmd_high = pmdp->pmd_high;
379 : smp_rmb();
380 : } while (unlikely(pmd.pmd_low != pmdp->pmd_low));
381 :
382 : return pmd;
383 : }
384 : #define pmdp_get_lockless pmdp_get_lockless
385 : #endif /* CONFIG_PGTABLE_LEVELS > 2 */
386 : #endif /* CONFIG_GUP_GET_PXX_LOW_HIGH */
387 :
388 : /*
389 : * We require that the PTE can be read atomically.
390 : */
391 : #ifndef ptep_get_lockless
392 : static inline pte_t ptep_get_lockless(pte_t *ptep)
393 : {
394 : return ptep_get(ptep);
395 : }
396 : #endif
397 :
398 : #ifndef pmdp_get_lockless
399 : static inline pmd_t pmdp_get_lockless(pmd_t *pmdp)
400 : {
401 0 : return pmdp_get(pmdp);
402 : }
403 : #endif
404 :
405 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
406 : #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
407 : static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
408 : unsigned long address,
409 : pmd_t *pmdp)
410 : {
411 : pmd_t pmd = *pmdp;
412 :
413 : pmd_clear(pmdp);
414 : page_table_check_pmd_clear(mm, address, pmd);
415 :
416 : return pmd;
417 : }
418 : #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */
419 : #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
420 : static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
421 : unsigned long address,
422 : pud_t *pudp)
423 : {
424 : pud_t pud = *pudp;
425 :
426 : pud_clear(pudp);
427 : page_table_check_pud_clear(mm, address, pud);
428 :
429 : return pud;
430 : }
431 : #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */
432 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
433 :
434 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
435 : #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
436 : static inline pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
437 : unsigned long address, pmd_t *pmdp,
438 : int full)
439 : {
440 : return pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
441 : }
442 : #endif
443 :
444 : #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL
445 : static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm,
446 : unsigned long address, pud_t *pudp,
447 : int full)
448 : {
449 : return pudp_huge_get_and_clear(mm, address, pudp);
450 : }
451 : #endif
452 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
453 :
454 : #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
455 : static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
456 : unsigned long address, pte_t *ptep,
457 : int full)
458 : {
459 0 : return ptep_get_and_clear(mm, address, ptep);
460 : }
461 : #endif
462 :
463 :
464 : /*
465 : * If two threads concurrently fault at the same page, the thread that
466 : * won the race updates the PTE and its local TLB/Cache. The other thread
467 : * gives up, simply does nothing, and continues; on architectures where
468 : * software can update TLB, local TLB can be updated here to avoid next page
469 : * fault. This function updates TLB only, do nothing with cache or others.
470 : * It is the difference with function update_mmu_cache.
471 : */
472 : #ifndef __HAVE_ARCH_UPDATE_MMU_TLB
473 : static inline void update_mmu_tlb(struct vm_area_struct *vma,
474 : unsigned long address, pte_t *ptep)
475 : {
476 : }
477 : #define __HAVE_ARCH_UPDATE_MMU_TLB
478 : #endif
479 :
480 : /*
481 : * Some architectures may be able to avoid expensive synchronization
482 : * primitives when modifications are made to PTE's which are already
483 : * not present, or in the process of an address space destruction.
484 : */
485 : #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
486 : static inline void pte_clear_not_present_full(struct mm_struct *mm,
487 : unsigned long address,
488 : pte_t *ptep,
489 : int full)
490 : {
491 0 : pte_clear(mm, address, ptep);
492 : }
493 : #endif
494 :
495 : #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
496 : extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
497 : unsigned long address,
498 : pte_t *ptep);
499 : #endif
500 :
501 : #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
502 : extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
503 : unsigned long address,
504 : pmd_t *pmdp);
505 : extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
506 : unsigned long address,
507 : pud_t *pudp);
508 : #endif
509 :
510 : #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
511 : struct mm_struct;
512 : static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
513 : {
514 0 : pte_t old_pte = *ptep;
515 0 : set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
516 : }
517 : #endif
518 :
519 : /*
520 : * On some architectures hardware does not set page access bit when accessing
521 : * memory page, it is responsibility of software setting this bit. It brings
522 : * out extra page fault penalty to track page access bit. For optimization page
523 : * access bit can be set during all page fault flow on these arches.
524 : * To be differentiate with macro pte_mkyoung, this macro is used on platforms
525 : * where software maintains page access bit.
526 : */
527 : #ifndef pte_sw_mkyoung
528 : static inline pte_t pte_sw_mkyoung(pte_t pte)
529 : {
530 : return pte;
531 : }
532 : #define pte_sw_mkyoung pte_sw_mkyoung
533 : #endif
534 :
535 : #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
536 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
537 : static inline void pmdp_set_wrprotect(struct mm_struct *mm,
538 : unsigned long address, pmd_t *pmdp)
539 : {
540 : pmd_t old_pmd = *pmdp;
541 : set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
542 : }
543 : #else
544 : static inline void pmdp_set_wrprotect(struct mm_struct *mm,
545 : unsigned long address, pmd_t *pmdp)
546 : {
547 : BUILD_BUG();
548 : }
549 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
550 : #endif
551 : #ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
552 : #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
553 : static inline void pudp_set_wrprotect(struct mm_struct *mm,
554 : unsigned long address, pud_t *pudp)
555 : {
556 : pud_t old_pud = *pudp;
557 :
558 : set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
559 : }
560 : #else
561 : static inline void pudp_set_wrprotect(struct mm_struct *mm,
562 : unsigned long address, pud_t *pudp)
563 : {
564 : BUILD_BUG();
565 : }
566 : #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
567 : #endif
568 :
569 : #ifndef pmdp_collapse_flush
570 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
571 : extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
572 : unsigned long address, pmd_t *pmdp);
573 : #else
574 : static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
575 : unsigned long address,
576 : pmd_t *pmdp)
577 : {
578 : BUILD_BUG();
579 : return *pmdp;
580 : }
581 : #define pmdp_collapse_flush pmdp_collapse_flush
582 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
583 : #endif
584 :
585 : #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
586 : extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
587 : pgtable_t pgtable);
588 : #endif
589 :
590 : #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
591 : extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
592 : #endif
593 :
594 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
595 : /*
596 : * This is an implementation of pmdp_establish() that is only suitable for an
597 : * architecture that doesn't have hardware dirty/accessed bits. In this case we
598 : * can't race with CPU which sets these bits and non-atomic approach is fine.
599 : */
600 : static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
601 : unsigned long address, pmd_t *pmdp, pmd_t pmd)
602 : {
603 : pmd_t old_pmd = *pmdp;
604 : set_pmd_at(vma->vm_mm, address, pmdp, pmd);
605 : return old_pmd;
606 : }
607 : #endif
608 :
609 : #ifndef __HAVE_ARCH_PMDP_INVALIDATE
610 : extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
611 : pmd_t *pmdp);
612 : #endif
613 :
614 : #ifndef __HAVE_ARCH_PMDP_INVALIDATE_AD
615 :
616 : /*
617 : * pmdp_invalidate_ad() invalidates the PMD while changing a transparent
618 : * hugepage mapping in the page tables. This function is similar to
619 : * pmdp_invalidate(), but should only be used if the access and dirty bits would
620 : * not be cleared by the software in the new PMD value. The function ensures
621 : * that hardware changes of the access and dirty bits updates would not be lost.
622 : *
623 : * Doing so can allow in certain architectures to avoid a TLB flush in most
624 : * cases. Yet, another TLB flush might be necessary later if the PMD update
625 : * itself requires such flush (e.g., if protection was set to be stricter). Yet,
626 : * even when a TLB flush is needed because of the update, the caller may be able
627 : * to batch these TLB flushing operations, so fewer TLB flush operations are
628 : * needed.
629 : */
630 : extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
631 : unsigned long address, pmd_t *pmdp);
632 : #endif
633 :
634 : #ifndef __HAVE_ARCH_PTE_SAME
635 : static inline int pte_same(pte_t pte_a, pte_t pte_b)
636 : {
637 : return pte_val(pte_a) == pte_val(pte_b);
638 : }
639 : #endif
640 :
641 : #ifndef __HAVE_ARCH_PTE_UNUSED
642 : /*
643 : * Some architectures provide facilities to virtualization guests
644 : * so that they can flag allocated pages as unused. This allows the
645 : * host to transparently reclaim unused pages. This function returns
646 : * whether the pte's page is unused.
647 : */
648 : static inline int pte_unused(pte_t pte)
649 : {
650 : return 0;
651 : }
652 : #endif
653 :
654 : #ifndef pte_access_permitted
655 : #define pte_access_permitted(pte, write) \
656 : (pte_present(pte) && (!(write) || pte_write(pte)))
657 : #endif
658 :
659 : #ifndef pmd_access_permitted
660 : #define pmd_access_permitted(pmd, write) \
661 : (pmd_present(pmd) && (!(write) || pmd_write(pmd)))
662 : #endif
663 :
664 : #ifndef pud_access_permitted
665 : #define pud_access_permitted(pud, write) \
666 : (pud_present(pud) && (!(write) || pud_write(pud)))
667 : #endif
668 :
669 : #ifndef p4d_access_permitted
670 : #define p4d_access_permitted(p4d, write) \
671 : (p4d_present(p4d) && (!(write) || p4d_write(p4d)))
672 : #endif
673 :
674 : #ifndef pgd_access_permitted
675 : #define pgd_access_permitted(pgd, write) \
676 : (pgd_present(pgd) && (!(write) || pgd_write(pgd)))
677 : #endif
678 :
679 : #ifndef __HAVE_ARCH_PMD_SAME
680 : static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
681 : {
682 : return pmd_val(pmd_a) == pmd_val(pmd_b);
683 : }
684 :
685 : static inline int pud_same(pud_t pud_a, pud_t pud_b)
686 : {
687 : return pud_val(pud_a) == pud_val(pud_b);
688 : }
689 : #endif
690 :
691 : #ifndef __HAVE_ARCH_P4D_SAME
692 : static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b)
693 : {
694 : return p4d_val(p4d_a) == p4d_val(p4d_b);
695 : }
696 : #endif
697 :
698 : #ifndef __HAVE_ARCH_PGD_SAME
699 : static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)
700 : {
701 : return pgd_val(pgd_a) == pgd_val(pgd_b);
702 : }
703 : #endif
704 :
705 : /*
706 : * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
707 : * TLB flush will be required as a result of the "set". For example, use
708 : * in scenarios where it is known ahead of time that the routine is
709 : * setting non-present entries, or re-setting an existing entry to the
710 : * same value. Otherwise, use the typical "set" helpers and flush the
711 : * TLB.
712 : */
713 : #define set_pte_safe(ptep, pte) \
714 : ({ \
715 : WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \
716 : set_pte(ptep, pte); \
717 : })
718 :
719 : #define set_pmd_safe(pmdp, pmd) \
720 : ({ \
721 : WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \
722 : set_pmd(pmdp, pmd); \
723 : })
724 :
725 : #define set_pud_safe(pudp, pud) \
726 : ({ \
727 : WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
728 : set_pud(pudp, pud); \
729 : })
730 :
731 : #define set_p4d_safe(p4dp, p4d) \
732 : ({ \
733 : WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
734 : set_p4d(p4dp, p4d); \
735 : })
736 :
737 : #define set_pgd_safe(pgdp, pgd) \
738 : ({ \
739 : WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \
740 : set_pgd(pgdp, pgd); \
741 : })
742 :
743 : #ifndef __HAVE_ARCH_DO_SWAP_PAGE
744 : /*
745 : * Some architectures support metadata associated with a page. When a
746 : * page is being swapped out, this metadata must be saved so it can be
747 : * restored when the page is swapped back in. SPARC M7 and newer
748 : * processors support an ADI (Application Data Integrity) tag for the
749 : * page as metadata for the page. arch_do_swap_page() can restore this
750 : * metadata when a page is swapped back in.
751 : */
752 : static inline void arch_do_swap_page(struct mm_struct *mm,
753 : struct vm_area_struct *vma,
754 : unsigned long addr,
755 : pte_t pte, pte_t oldpte)
756 : {
757 :
758 : }
759 : #endif
760 :
761 : #ifndef __HAVE_ARCH_UNMAP_ONE
762 : /*
763 : * Some architectures support metadata associated with a page. When a
764 : * page is being swapped out, this metadata must be saved so it can be
765 : * restored when the page is swapped back in. SPARC M7 and newer
766 : * processors support an ADI (Application Data Integrity) tag for the
767 : * page as metadata for the page. arch_unmap_one() can save this
768 : * metadata on a swap-out of a page.
769 : */
770 : static inline int arch_unmap_one(struct mm_struct *mm,
771 : struct vm_area_struct *vma,
772 : unsigned long addr,
773 : pte_t orig_pte)
774 : {
775 : return 0;
776 : }
777 : #endif
778 :
779 : /*
780 : * Allow architectures to preserve additional metadata associated with
781 : * swapped-out pages. The corresponding __HAVE_ARCH_SWAP_* macros and function
782 : * prototypes must be defined in the arch-specific asm/pgtable.h file.
783 : */
784 : #ifndef __HAVE_ARCH_PREPARE_TO_SWAP
785 : static inline int arch_prepare_to_swap(struct page *page)
786 : {
787 : return 0;
788 : }
789 : #endif
790 :
791 : #ifndef __HAVE_ARCH_SWAP_INVALIDATE
792 : static inline void arch_swap_invalidate_page(int type, pgoff_t offset)
793 : {
794 : }
795 :
796 : static inline void arch_swap_invalidate_area(int type)
797 : {
798 : }
799 : #endif
800 :
801 : #ifndef __HAVE_ARCH_SWAP_RESTORE
802 : static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio)
803 : {
804 : }
805 : #endif
806 :
807 : #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
808 : #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
809 : #endif
810 :
811 : #ifndef __HAVE_ARCH_MOVE_PTE
812 : #define move_pte(pte, prot, old_addr, new_addr) (pte)
813 : #endif
814 :
815 : #ifndef pte_accessible
816 : # define pte_accessible(mm, pte) ((void)(pte), 1)
817 : #endif
818 :
819 : #ifndef flush_tlb_fix_spurious_fault
820 : #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
821 : #endif
822 :
823 : /*
824 : * When walking page tables, get the address of the next boundary,
825 : * or the end address of the range if that comes earlier. Although no
826 : * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
827 : */
828 :
829 : #define pgd_addr_end(addr, end) \
830 : ({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
831 : (__boundary - 1 < (end) - 1)? __boundary: (end); \
832 : })
833 :
834 : #ifndef p4d_addr_end
835 : #define p4d_addr_end(addr, end) \
836 : ({ unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK; \
837 : (__boundary - 1 < (end) - 1)? __boundary: (end); \
838 : })
839 : #endif
840 :
841 : #ifndef pud_addr_end
842 : #define pud_addr_end(addr, end) \
843 : ({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \
844 : (__boundary - 1 < (end) - 1)? __boundary: (end); \
845 : })
846 : #endif
847 :
848 : #ifndef pmd_addr_end
849 : #define pmd_addr_end(addr, end) \
850 : ({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \
851 : (__boundary - 1 < (end) - 1)? __boundary: (end); \
852 : })
853 : #endif
854 :
855 : /*
856 : * When walking page tables, we usually want to skip any p?d_none entries;
857 : * and any p?d_bad entries - reporting the error before resetting to none.
858 : * Do the tests inline, but report and clear the bad entry in mm/memory.c.
859 : */
860 : void pgd_clear_bad(pgd_t *);
861 :
862 : #ifndef __PAGETABLE_P4D_FOLDED
863 : void p4d_clear_bad(p4d_t *);
864 : #else
865 : #define p4d_clear_bad(p4d) do { } while (0)
866 : #endif
867 :
868 : #ifndef __PAGETABLE_PUD_FOLDED
869 : void pud_clear_bad(pud_t *);
870 : #else
871 : #define pud_clear_bad(p4d) do { } while (0)
872 : #endif
873 :
874 : void pmd_clear_bad(pmd_t *);
875 :
876 : static inline int pgd_none_or_clear_bad(pgd_t *pgd)
877 : {
878 258 : if (pgd_none(*pgd))
879 : return 1;
880 258 : if (unlikely(pgd_bad(*pgd))) {
881 : pgd_clear_bad(pgd);
882 : return 1;
883 : }
884 : return 0;
885 : }
886 :
887 : static inline int p4d_none_or_clear_bad(p4d_t *p4d)
888 : {
889 258 : if (p4d_none(*p4d))
890 : return 1;
891 258 : if (unlikely(p4d_bad(*p4d))) {
892 : p4d_clear_bad(p4d);
893 : return 1;
894 : }
895 : return 0;
896 : }
897 :
898 : static inline int pud_none_or_clear_bad(pud_t *pud)
899 : {
900 258 : if (pud_none(*pud))
901 : return 1;
902 258 : if (unlikely(pud_bad(*pud))) {
903 : pud_clear_bad(pud);
904 : return 1;
905 : }
906 : return 0;
907 : }
908 :
909 : static inline int pmd_none_or_clear_bad(pmd_t *pmd)
910 : {
911 338 : if (pmd_none(*pmd))
912 : return 1;
913 337 : if (unlikely(pmd_bad(*pmd))) {
914 0 : pmd_clear_bad(pmd);
915 : return 1;
916 : }
917 : return 0;
918 : }
919 :
920 : static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma,
921 : unsigned long addr,
922 : pte_t *ptep)
923 : {
924 : /*
925 : * Get the current pte state, but zero it out to make it
926 : * non-present, preventing the hardware from asynchronously
927 : * updating it.
928 : */
929 0 : return ptep_get_and_clear(vma->vm_mm, addr, ptep);
930 : }
931 :
932 : static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma,
933 : unsigned long addr,
934 : pte_t *ptep, pte_t pte)
935 : {
936 : /*
937 : * The pte is non-present, so there's no hardware state to
938 : * preserve.
939 : */
940 0 : set_pte_at(vma->vm_mm, addr, ptep, pte);
941 : }
942 :
943 : #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
944 : /*
945 : * Start a pte protection read-modify-write transaction, which
946 : * protects against asynchronous hardware modifications to the pte.
947 : * The intention is not to prevent the hardware from making pte
948 : * updates, but to prevent any updates it may make from being lost.
949 : *
950 : * This does not protect against other software modifications of the
951 : * pte; the appropriate pte lock must be held over the transaction.
952 : *
953 : * Note that this interface is intended to be batchable, meaning that
954 : * ptep_modify_prot_commit may not actually update the pte, but merely
955 : * queue the update to be done at some later time. The update must be
956 : * actually committed before the pte lock is released, however.
957 : */
958 : static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
959 : unsigned long addr,
960 : pte_t *ptep)
961 : {
962 0 : return __ptep_modify_prot_start(vma, addr, ptep);
963 : }
964 :
965 : /*
966 : * Commit an update to a pte, leaving any hardware-controlled bits in
967 : * the PTE unmodified.
968 : */
969 : static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
970 : unsigned long addr,
971 : pte_t *ptep, pte_t old_pte, pte_t pte)
972 : {
973 0 : __ptep_modify_prot_commit(vma, addr, ptep, pte);
974 : }
975 : #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
976 : #endif /* CONFIG_MMU */
977 :
978 : /*
979 : * No-op macros that just return the current protection value. Defined here
980 : * because these macros can be used even if CONFIG_MMU is not defined.
981 : */
982 :
983 : #ifndef pgprot_nx
984 : #define pgprot_nx(prot) (prot)
985 : #endif
986 :
987 : #ifndef pgprot_noncached
988 : #define pgprot_noncached(prot) (prot)
989 : #endif
990 :
991 : #ifndef pgprot_writecombine
992 : #define pgprot_writecombine pgprot_noncached
993 : #endif
994 :
995 : #ifndef pgprot_writethrough
996 : #define pgprot_writethrough pgprot_noncached
997 : #endif
998 :
999 : #ifndef pgprot_device
1000 : #define pgprot_device pgprot_noncached
1001 : #endif
1002 :
1003 : #ifndef pgprot_mhp
1004 : #define pgprot_mhp(prot) (prot)
1005 : #endif
1006 :
1007 : #ifdef CONFIG_MMU
1008 : #ifndef pgprot_modify
1009 : #define pgprot_modify pgprot_modify
1010 : static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
1011 : {
1012 : if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
1013 : newprot = pgprot_noncached(newprot);
1014 : if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
1015 : newprot = pgprot_writecombine(newprot);
1016 : if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
1017 : newprot = pgprot_device(newprot);
1018 : return newprot;
1019 : }
1020 : #endif
1021 : #endif /* CONFIG_MMU */
1022 :
1023 : #ifndef pgprot_encrypted
1024 : #define pgprot_encrypted(prot) (prot)
1025 : #endif
1026 :
1027 : #ifndef pgprot_decrypted
1028 : #define pgprot_decrypted(prot) (prot)
1029 : #endif
1030 :
1031 : /*
1032 : * A facility to provide lazy MMU batching. This allows PTE updates and
1033 : * page invalidations to be delayed until a call to leave lazy MMU mode
1034 : * is issued. Some architectures may benefit from doing this, and it is
1035 : * beneficial for both shadow and direct mode hypervisors, which may batch
1036 : * the PTE updates which happen during this window. Note that using this
1037 : * interface requires that read hazards be removed from the code. A read
1038 : * hazard could result in the direct mode hypervisor case, since the actual
1039 : * write to the page tables may not yet have taken place, so reads though
1040 : * a raw PTE pointer after it has been modified are not guaranteed to be
1041 : * up to date. This mode can only be entered and left under the protection of
1042 : * the page table locks for all page tables which may be modified. In the UP
1043 : * case, this is required so that preemption is disabled, and in the SMP case,
1044 : * it must synchronize the delayed page table writes properly on other CPUs.
1045 : */
1046 : #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
1047 : #define arch_enter_lazy_mmu_mode() do {} while (0)
1048 : #define arch_leave_lazy_mmu_mode() do {} while (0)
1049 : #define arch_flush_lazy_mmu_mode() do {} while (0)
1050 : #endif
1051 :
1052 : /*
1053 : * A facility to provide batching of the reload of page tables and
1054 : * other process state with the actual context switch code for
1055 : * paravirtualized guests. By convention, only one of the batched
1056 : * update (lazy) modes (CPU, MMU) should be active at any given time,
1057 : * entry should never be nested, and entry and exits should always be
1058 : * paired. This is for sanity of maintaining and reasoning about the
1059 : * kernel code. In this case, the exit (end of the context switch) is
1060 : * in architecture-specific code, and so doesn't need a generic
1061 : * definition.
1062 : */
1063 : #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
1064 : #define arch_start_context_switch(prev) do {} while (0)
1065 : #endif
1066 :
1067 : #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
1068 : #ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
1069 : static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
1070 : {
1071 : return pmd;
1072 : }
1073 :
1074 : static inline int pmd_swp_soft_dirty(pmd_t pmd)
1075 : {
1076 : return 0;
1077 : }
1078 :
1079 : static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
1080 : {
1081 : return pmd;
1082 : }
1083 : #endif
1084 : #else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
1085 : static inline int pte_soft_dirty(pte_t pte)
1086 : {
1087 : return 0;
1088 : }
1089 :
1090 : static inline int pmd_soft_dirty(pmd_t pmd)
1091 : {
1092 : return 0;
1093 : }
1094 :
1095 : static inline pte_t pte_mksoft_dirty(pte_t pte)
1096 : {
1097 : return pte;
1098 : }
1099 :
1100 : static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
1101 : {
1102 : return pmd;
1103 : }
1104 :
1105 : static inline pte_t pte_clear_soft_dirty(pte_t pte)
1106 : {
1107 : return pte;
1108 : }
1109 :
1110 : static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
1111 : {
1112 : return pmd;
1113 : }
1114 :
1115 : static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
1116 : {
1117 : return pte;
1118 : }
1119 :
1120 : static inline int pte_swp_soft_dirty(pte_t pte)
1121 : {
1122 : return 0;
1123 : }
1124 :
1125 : static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
1126 : {
1127 : return pte;
1128 : }
1129 :
1130 : static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
1131 : {
1132 : return pmd;
1133 : }
1134 :
1135 : static inline int pmd_swp_soft_dirty(pmd_t pmd)
1136 : {
1137 : return 0;
1138 : }
1139 :
1140 : static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
1141 : {
1142 : return pmd;
1143 : }
1144 : #endif
1145 :
1146 : #ifndef __HAVE_PFNMAP_TRACKING
1147 : /*
1148 : * Interfaces that can be used by architecture code to keep track of
1149 : * memory type of pfn mappings specified by the remap_pfn_range,
1150 : * vmf_insert_pfn.
1151 : */
1152 :
1153 : /*
1154 : * track_pfn_remap is called when a _new_ pfn mapping is being established
1155 : * by remap_pfn_range() for physical range indicated by pfn and size.
1156 : */
1157 : static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
1158 : unsigned long pfn, unsigned long addr,
1159 : unsigned long size)
1160 : {
1161 : return 0;
1162 : }
1163 :
1164 : /*
1165 : * track_pfn_insert is called when a _new_ single pfn is established
1166 : * by vmf_insert_pfn().
1167 : */
1168 : static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
1169 : pfn_t pfn)
1170 : {
1171 : }
1172 :
1173 : /*
1174 : * track_pfn_copy is called when vma that is covering the pfnmap gets
1175 : * copied through copy_page_range().
1176 : */
1177 : static inline int track_pfn_copy(struct vm_area_struct *vma)
1178 : {
1179 : return 0;
1180 : }
1181 :
1182 : /*
1183 : * untrack_pfn is called while unmapping a pfnmap for a region.
1184 : * untrack can be called for a specific region indicated by pfn and size or
1185 : * can be for the entire vma (in which case pfn, size are zero).
1186 : */
1187 : static inline void untrack_pfn(struct vm_area_struct *vma,
1188 : unsigned long pfn, unsigned long size,
1189 : bool mm_wr_locked)
1190 : {
1191 : }
1192 :
1193 : /*
1194 : * untrack_pfn_moved is called while mremapping a pfnmap for a new region.
1195 : */
1196 : static inline void untrack_pfn_moved(struct vm_area_struct *vma)
1197 : {
1198 : }
1199 : #else
1200 : extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
1201 : unsigned long pfn, unsigned long addr,
1202 : unsigned long size);
1203 : extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
1204 : pfn_t pfn);
1205 : extern int track_pfn_copy(struct vm_area_struct *vma);
1206 : extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
1207 : unsigned long size, bool mm_wr_locked);
1208 : extern void untrack_pfn_moved(struct vm_area_struct *vma);
1209 : #endif
1210 :
1211 : #ifdef CONFIG_MMU
1212 : #ifdef __HAVE_COLOR_ZERO_PAGE
1213 : static inline int is_zero_pfn(unsigned long pfn)
1214 : {
1215 : extern unsigned long zero_pfn;
1216 : unsigned long offset_from_zero_pfn = pfn - zero_pfn;
1217 : return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
1218 : }
1219 :
1220 : #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr))
1221 :
1222 : #else
1223 : static inline int is_zero_pfn(unsigned long pfn)
1224 : {
1225 : extern unsigned long zero_pfn;
1226 0 : return pfn == zero_pfn;
1227 : }
1228 :
1229 : static inline unsigned long my_zero_pfn(unsigned long addr)
1230 : {
1231 : extern unsigned long zero_pfn;
1232 0 : return zero_pfn;
1233 : }
1234 : #endif
1235 : #else
1236 : static inline int is_zero_pfn(unsigned long pfn)
1237 : {
1238 : return 0;
1239 : }
1240 :
1241 : static inline unsigned long my_zero_pfn(unsigned long addr)
1242 : {
1243 : return 0;
1244 : }
1245 : #endif /* CONFIG_MMU */
1246 :
1247 : #ifdef CONFIG_MMU
1248 :
1249 : #ifndef CONFIG_TRANSPARENT_HUGEPAGE
1250 : static inline int pmd_trans_huge(pmd_t pmd)
1251 : {
1252 : return 0;
1253 : }
1254 : #ifndef pmd_write
1255 : static inline int pmd_write(pmd_t pmd)
1256 : {
1257 : BUG();
1258 : return 0;
1259 : }
1260 : #endif /* pmd_write */
1261 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1262 :
1263 : #ifndef pud_write
1264 : static inline int pud_write(pud_t pud)
1265 : {
1266 : BUG();
1267 : return 0;
1268 : }
1269 : #endif /* pud_write */
1270 :
1271 : #if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
1272 : static inline int pmd_devmap(pmd_t pmd)
1273 : {
1274 : return 0;
1275 : }
1276 : static inline int pud_devmap(pud_t pud)
1277 : {
1278 : return 0;
1279 : }
1280 : static inline int pgd_devmap(pgd_t pgd)
1281 : {
1282 : return 0;
1283 : }
1284 : #endif
1285 :
1286 : #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
1287 : !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
1288 : static inline int pud_trans_huge(pud_t pud)
1289 : {
1290 : return 0;
1291 : }
1292 : #endif
1293 :
1294 : /* See pmd_none_or_trans_huge_or_clear_bad for discussion. */
1295 : static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud)
1296 : {
1297 : pud_t pudval = READ_ONCE(*pud);
1298 :
1299 : if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
1300 : return 1;
1301 : if (unlikely(pud_bad(pudval))) {
1302 : pud_clear_bad(pud);
1303 : return 1;
1304 : }
1305 : return 0;
1306 : }
1307 :
1308 : /* See pmd_trans_unstable for discussion. */
1309 : static inline int pud_trans_unstable(pud_t *pud)
1310 : {
1311 : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
1312 : defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
1313 : return pud_none_or_trans_huge_or_dev_or_clear_bad(pud);
1314 : #else
1315 : return 0;
1316 : #endif
1317 : }
1318 :
1319 : #ifndef arch_needs_pgtable_deposit
1320 : #define arch_needs_pgtable_deposit() (false)
1321 : #endif
1322 : /*
1323 : * This function is meant to be used by sites walking pagetables with
1324 : * the mmap_lock held in read mode to protect against MADV_DONTNEED and
1325 : * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
1326 : * into a null pmd and the transhuge page fault can convert a null pmd
1327 : * into an hugepmd or into a regular pmd (if the hugepage allocation
1328 : * fails). While holding the mmap_lock in read mode the pmd becomes
1329 : * stable and stops changing under us only if it's not null and not a
1330 : * transhuge pmd. When those races occurs and this function makes a
1331 : * difference vs the standard pmd_none_or_clear_bad, the result is
1332 : * undefined so behaving like if the pmd was none is safe (because it
1333 : * can return none anyway). The compiler level barrier() is critically
1334 : * important to compute the two checks atomically on the same pmdval.
1335 : *
1336 : * For 32bit kernels with a 64bit large pmd_t this automatically takes
1337 : * care of reading the pmd atomically to avoid SMP race conditions
1338 : * against pmd_populate() when the mmap_lock is hold for reading by the
1339 : * caller (a special atomic read not done by "gcc" as in the generic
1340 : * version above, is also needed when THP is disabled because the page
1341 : * fault can populate the pmd from under us).
1342 : */
1343 0 : static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
1344 : {
1345 0 : pmd_t pmdval = pmdp_get_lockless(pmd);
1346 : /*
1347 : * The barrier will stabilize the pmdval in a register or on
1348 : * the stack so that it will stop changing under the code.
1349 : *
1350 : * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
1351 : * pmdp_get_lockless is allowed to return a not atomic pmdval
1352 : * (for example pointing to an hugepage that has never been
1353 : * mapped in the pmd). The below checks will only care about
1354 : * the low part of the pmd with 32bit PAE x86 anyway, with the
1355 : * exception of pmd_none(). So the important thing is that if
1356 : * the low part of the pmd is found null, the high part will
1357 : * be also null or the pmd_none() check below would be
1358 : * confused.
1359 : */
1360 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1361 : barrier();
1362 : #endif
1363 : /*
1364 : * !pmd_present() checks for pmd migration entries
1365 : *
1366 : * The complete check uses is_pmd_migration_entry() in linux/swapops.h
1367 : * But using that requires moving current function and pmd_trans_unstable()
1368 : * to linux/swapops.h to resolve dependency, which is too much code move.
1369 : *
1370 : * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
1371 : * because !pmd_present() pages can only be under migration not swapped
1372 : * out.
1373 : *
1374 : * pmd_none() is preserved for future condition checks on pmd migration
1375 : * entries and not confusing with this function name, although it is
1376 : * redundant with !pmd_present().
1377 : */
1378 0 : if (pmd_none(pmdval) || pmd_trans_huge(pmdval) ||
1379 : (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval)))
1380 : return 1;
1381 0 : if (unlikely(pmd_bad(pmdval))) {
1382 0 : pmd_clear_bad(pmd);
1383 0 : return 1;
1384 : }
1385 : return 0;
1386 : }
1387 :
1388 : /*
1389 : * This is a noop if Transparent Hugepage Support is not built into
1390 : * the kernel. Otherwise it is equivalent to
1391 : * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
1392 : * places that already verified the pmd is not none and they want to
1393 : * walk ptes while holding the mmap sem in read mode (write mode don't
1394 : * need this). If THP is not enabled, the pmd can't go away under the
1395 : * code even if MADV_DONTNEED runs, but if THP is enabled we need to
1396 : * run a pmd_trans_unstable before walking the ptes after
1397 : * split_huge_pmd returns (because it may have run when the pmd become
1398 : * null, but then a page fault can map in a THP and not a regular page).
1399 : */
1400 : static inline int pmd_trans_unstable(pmd_t *pmd)
1401 : {
1402 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1403 : return pmd_none_or_trans_huge_or_clear_bad(pmd);
1404 : #else
1405 : return 0;
1406 : #endif
1407 : }
1408 :
1409 : /*
1410 : * the ordering of these checks is important for pmds with _page_devmap set.
1411 : * if we check pmd_trans_unstable() first we will trip the bad_pmd() check
1412 : * inside of pmd_none_or_trans_huge_or_clear_bad(). this will end up correctly
1413 : * returning 1 but not before it spams dmesg with the pmd_clear_bad() output.
1414 : */
1415 : static inline int pmd_devmap_trans_unstable(pmd_t *pmd)
1416 : {
1417 0 : return pmd_devmap(*pmd) || pmd_trans_unstable(pmd);
1418 : }
1419 :
1420 : #ifndef CONFIG_NUMA_BALANCING
1421 : /*
1422 : * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
1423 : * the only case the kernel cares is for NUMA balancing and is only ever set
1424 : * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
1425 : * _PAGE_PROTNONE so by default, implement the helper as "always no". It
1426 : * is the responsibility of the caller to distinguish between PROT_NONE
1427 : * protections and NUMA hinting fault protections.
1428 : */
1429 : static inline int pte_protnone(pte_t pte)
1430 : {
1431 : return 0;
1432 : }
1433 :
1434 : static inline int pmd_protnone(pmd_t pmd)
1435 : {
1436 : return 0;
1437 : }
1438 : #endif /* CONFIG_NUMA_BALANCING */
1439 :
1440 : #endif /* CONFIG_MMU */
1441 :
1442 : #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
1443 :
1444 : #ifndef __PAGETABLE_P4D_FOLDED
1445 : int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot);
1446 : void p4d_clear_huge(p4d_t *p4d);
1447 : #else
1448 : static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1449 : {
1450 : return 0;
1451 : }
1452 : static inline void p4d_clear_huge(p4d_t *p4d) { }
1453 : #endif /* !__PAGETABLE_P4D_FOLDED */
1454 :
1455 : int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
1456 : int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
1457 : int pud_clear_huge(pud_t *pud);
1458 : int pmd_clear_huge(pmd_t *pmd);
1459 : int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
1460 : int pud_free_pmd_page(pud_t *pud, unsigned long addr);
1461 : int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
1462 : #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
1463 : static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
1464 : {
1465 : return 0;
1466 : }
1467 : static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
1468 : {
1469 : return 0;
1470 : }
1471 : static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
1472 : {
1473 : return 0;
1474 : }
1475 : static inline void p4d_clear_huge(p4d_t *p4d) { }
1476 : static inline int pud_clear_huge(pud_t *pud)
1477 : {
1478 : return 0;
1479 : }
1480 : static inline int pmd_clear_huge(pmd_t *pmd)
1481 : {
1482 : return 0;
1483 : }
1484 : static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1485 : {
1486 : return 0;
1487 : }
1488 : static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
1489 : {
1490 : return 0;
1491 : }
1492 : static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
1493 : {
1494 : return 0;
1495 : }
1496 : #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
1497 :
1498 : #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
1499 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1500 : /*
1501 : * ARCHes with special requirements for evicting THP backing TLB entries can
1502 : * implement this. Otherwise also, it can help optimize normal TLB flush in
1503 : * THP regime. Stock flush_tlb_range() typically has optimization to nuke the
1504 : * entire TLB if flush span is greater than a threshold, which will
1505 : * likely be true for a single huge page. Thus a single THP flush will
1506 : * invalidate the entire TLB which is not desirable.
1507 : * e.g. see arch/arc: flush_pmd_tlb_range
1508 : */
1509 : #define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
1510 : #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
1511 : #else
1512 : #define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
1513 : #define flush_pud_tlb_range(vma, addr, end) BUILD_BUG()
1514 : #endif
1515 : #endif
1516 :
1517 : struct file;
1518 : int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
1519 : unsigned long size, pgprot_t *vma_prot);
1520 :
1521 : #ifndef CONFIG_X86_ESPFIX64
1522 : static inline void init_espfix_bsp(void) { }
1523 : #endif
1524 :
1525 : extern void __init pgtable_cache_init(void);
1526 :
1527 : #ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
1528 : static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
1529 : {
1530 : return true;
1531 : }
1532 :
1533 : static inline bool arch_has_pfn_modify_check(void)
1534 : {
1535 : return false;
1536 : }
1537 : #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
1538 :
1539 : /*
1540 : * Architecture PAGE_KERNEL_* fallbacks
1541 : *
1542 : * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
1543 : * because they really don't support them, or the port needs to be updated to
1544 : * reflect the required functionality. Below are a set of relatively safe
1545 : * fallbacks, as best effort, which we can count on in lieu of the architectures
1546 : * not defining them on their own yet.
1547 : */
1548 :
1549 : #ifndef PAGE_KERNEL_RO
1550 : # define PAGE_KERNEL_RO PAGE_KERNEL
1551 : #endif
1552 :
1553 : #ifndef PAGE_KERNEL_EXEC
1554 : # define PAGE_KERNEL_EXEC PAGE_KERNEL
1555 : #endif
1556 :
1557 : /*
1558 : * Page Table Modification bits for pgtbl_mod_mask.
1559 : *
1560 : * These are used by the p?d_alloc_track*() set of functions an in the generic
1561 : * vmalloc/ioremap code to track at which page-table levels entries have been
1562 : * modified. Based on that the code can better decide when vmalloc and ioremap
1563 : * mapping changes need to be synchronized to other page-tables in the system.
1564 : */
1565 : #define __PGTBL_PGD_MODIFIED 0
1566 : #define __PGTBL_P4D_MODIFIED 1
1567 : #define __PGTBL_PUD_MODIFIED 2
1568 : #define __PGTBL_PMD_MODIFIED 3
1569 : #define __PGTBL_PTE_MODIFIED 4
1570 :
1571 : #define PGTBL_PGD_MODIFIED BIT(__PGTBL_PGD_MODIFIED)
1572 : #define PGTBL_P4D_MODIFIED BIT(__PGTBL_P4D_MODIFIED)
1573 : #define PGTBL_PUD_MODIFIED BIT(__PGTBL_PUD_MODIFIED)
1574 : #define PGTBL_PMD_MODIFIED BIT(__PGTBL_PMD_MODIFIED)
1575 : #define PGTBL_PTE_MODIFIED BIT(__PGTBL_PTE_MODIFIED)
1576 :
1577 : /* Page-Table Modification Mask */
1578 : typedef unsigned int pgtbl_mod_mask;
1579 :
1580 : #endif /* !__ASSEMBLY__ */
1581 :
1582 : #if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT)
1583 : #ifdef CONFIG_PHYS_ADDR_T_64BIT
1584 : /*
1585 : * ZSMALLOC needs to know the highest PFN on 32-bit architectures
1586 : * with physical address space extension, but falls back to
1587 : * BITS_PER_LONG otherwise.
1588 : */
1589 : #error Missing MAX_POSSIBLE_PHYSMEM_BITS definition
1590 : #else
1591 : #define MAX_POSSIBLE_PHYSMEM_BITS 32
1592 : #endif
1593 : #endif
1594 :
1595 : #ifndef has_transparent_hugepage
1596 : #define has_transparent_hugepage() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE)
1597 : #endif
1598 :
1599 : /*
1600 : * On some architectures it depends on the mm if the p4d/pud or pmd
1601 : * layer of the page table hierarchy is folded or not.
1602 : */
1603 : #ifndef mm_p4d_folded
1604 : #define mm_p4d_folded(mm) __is_defined(__PAGETABLE_P4D_FOLDED)
1605 : #endif
1606 :
1607 : #ifndef mm_pud_folded
1608 : #define mm_pud_folded(mm) __is_defined(__PAGETABLE_PUD_FOLDED)
1609 : #endif
1610 :
1611 : #ifndef mm_pmd_folded
1612 : #define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED)
1613 : #endif
1614 :
1615 : #ifndef p4d_offset_lockless
1616 : #define p4d_offset_lockless(pgdp, pgd, address) p4d_offset(&(pgd), address)
1617 : #endif
1618 : #ifndef pud_offset_lockless
1619 : #define pud_offset_lockless(p4dp, p4d, address) pud_offset(&(p4d), address)
1620 : #endif
1621 : #ifndef pmd_offset_lockless
1622 : #define pmd_offset_lockless(pudp, pud, address) pmd_offset(&(pud), address)
1623 : #endif
1624 :
1625 : /*
1626 : * p?d_leaf() - true if this entry is a final mapping to a physical address.
1627 : * This differs from p?d_huge() by the fact that they are always available (if
1628 : * the architecture supports large pages at the appropriate level) even
1629 : * if CONFIG_HUGETLB_PAGE is not defined.
1630 : * Only meaningful when called on a valid entry.
1631 : */
1632 : #ifndef pgd_leaf
1633 : #define pgd_leaf(x) 0
1634 : #endif
1635 : #ifndef p4d_leaf
1636 : #define p4d_leaf(x) 0
1637 : #endif
1638 : #ifndef pud_leaf
1639 : #define pud_leaf(x) 0
1640 : #endif
1641 : #ifndef pmd_leaf
1642 : #define pmd_leaf(x) 0
1643 : #endif
1644 :
1645 : #ifndef pgd_leaf_size
1646 : #define pgd_leaf_size(x) (1ULL << PGDIR_SHIFT)
1647 : #endif
1648 : #ifndef p4d_leaf_size
1649 : #define p4d_leaf_size(x) P4D_SIZE
1650 : #endif
1651 : #ifndef pud_leaf_size
1652 : #define pud_leaf_size(x) PUD_SIZE
1653 : #endif
1654 : #ifndef pmd_leaf_size
1655 : #define pmd_leaf_size(x) PMD_SIZE
1656 : #endif
1657 : #ifndef pte_leaf_size
1658 : #define pte_leaf_size(x) PAGE_SIZE
1659 : #endif
1660 :
1661 : /*
1662 : * Some architectures have MMUs that are configurable or selectable at boot
1663 : * time. These lead to variable PTRS_PER_x. For statically allocated arrays it
1664 : * helps to have a static maximum value.
1665 : */
1666 :
1667 : #ifndef MAX_PTRS_PER_PTE
1668 : #define MAX_PTRS_PER_PTE PTRS_PER_PTE
1669 : #endif
1670 :
1671 : #ifndef MAX_PTRS_PER_PMD
1672 : #define MAX_PTRS_PER_PMD PTRS_PER_PMD
1673 : #endif
1674 :
1675 : #ifndef MAX_PTRS_PER_PUD
1676 : #define MAX_PTRS_PER_PUD PTRS_PER_PUD
1677 : #endif
1678 :
1679 : #ifndef MAX_PTRS_PER_P4D
1680 : #define MAX_PTRS_PER_P4D PTRS_PER_P4D
1681 : #endif
1682 :
1683 : /* description of effects of mapping type and prot in current implementation.
1684 : * this is due to the limited x86 page protection hardware. The expected
1685 : * behavior is in parens:
1686 : *
1687 : * map_type prot
1688 : * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
1689 : * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
1690 : * w: (no) no w: (no) no w: (yes) yes w: (no) no
1691 : * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
1692 : *
1693 : * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
1694 : * w: (no) no w: (no) no w: (copy) copy w: (no) no
1695 : * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
1696 : *
1697 : * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
1698 : * MAP_PRIVATE (with Enhanced PAN supported):
1699 : * r: (no) no
1700 : * w: (no) no
1701 : * x: (yes) yes
1702 : */
1703 : #define DECLARE_VM_GET_PAGE_PROT \
1704 : pgprot_t vm_get_page_prot(unsigned long vm_flags) \
1705 : { \
1706 : return protection_map[vm_flags & \
1707 : (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)]; \
1708 : } \
1709 : EXPORT_SYMBOL(vm_get_page_prot);
1710 :
1711 : #endif /* _LINUX_PGTABLE_H */
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