1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SWAPOPS_H
3 #define _LINUX_SWAPOPS_H
4
5 #include <linux/radix-tree.h>
6 #include <linux/bug.h>
7 #include <linux/mm_types.h>
8
9 #ifdef CONFIG_MMU
10
11 #ifdef CONFIG_SWAP
12 #include <linux/swapfile.h>
13 #endif /* CONFIG_SWAP */
14
15 /*
16 * swapcache pages are stored in the swapper_space radix tree. We want to
17 * get good packing density in that tree, so the index should be dense in
18 * the low-order bits.
19 *
20 * We arrange the `type' and `offset' fields so that `type' is at the six
21 * high-order bits of the swp_entry_t and `offset' is right-aligned in the
22 * remaining bits. Although `type' itself needs only five bits, we allow for
23 * shmem/tmpfs to shift it all up a further one bit: see swp_to_radix_entry().
24 *
25 * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
26 */
27 #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
28 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
29
30 /*
31 * Definitions only for PFN swap entries (see is_pfn_swap_entry()). To
32 * store PFN, we only need SWP_PFN_BITS bits. Each of the pfn swap entries
33 * can use the extra bits to store other information besides PFN.
34 */
35 #ifdef MAX_PHYSMEM_BITS
36 #define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
37 #else /* MAX_PHYSMEM_BITS */
38 #define SWP_PFN_BITS min_t(int, \
39 sizeof(phys_addr_t) * 8 - PAGE_SHIFT, \
40 SWP_TYPE_SHIFT)
41 #endif /* MAX_PHYSMEM_BITS */
42 #define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1)
43
44 /**
45 * Migration swap entry specific bitfield definitions. Layout:
46 *
47 * |----------+--------------------|
48 * | swp_type | swp_offset |
49 * |----------+--------+-+-+-------|
50 * | | resv |D|A| PFN |
51 * |----------+--------+-+-+-------|
52 *
53 * @SWP_MIG_YOUNG_BIT: Whether the page used to have young bit set (bit A)
54 * @SWP_MIG_DIRTY_BIT: Whether the page used to have dirty bit set (bit D)
55 *
56 * Note: A/D bits will be stored in migration entries iff there're enough
57 * free bits in arch specific swp offset. By default we'll ignore A/D bits
58 * when migrating a page. Please refer to migration_entry_supports_ad()
59 * for more information. If there're more bits besides PFN and A/D bits,
60 * they should be reserved and always be zeros.
61 */
62 #define SWP_MIG_YOUNG_BIT (SWP_PFN_BITS)
63 #define SWP_MIG_DIRTY_BIT (SWP_PFN_BITS + 1)
64 #define SWP_MIG_TOTAL_BITS (SWP_PFN_BITS + 2)
65
66 #define SWP_MIG_YOUNG BIT(SWP_MIG_YOUNG_BIT)
67 #define SWP_MIG_DIRTY BIT(SWP_MIG_DIRTY_BIT)
68
69 static inline bool is_pfn_swap_entry(swp_entry_t entry);
70
71 /* Clear all flags but only keep swp_entry_t related information */
pte_swp_clear_flags(pte_t pte)72 static inline pte_t pte_swp_clear_flags(pte_t pte)
73 {
74 if (pte_swp_exclusive(pte))
75 pte = pte_swp_clear_exclusive(pte);
76 if (pte_swp_soft_dirty(pte))
77 pte = pte_swp_clear_soft_dirty(pte);
78 if (pte_swp_uffd_wp(pte))
79 pte = pte_swp_clear_uffd_wp(pte);
80 return pte;
81 }
82
83 /*
84 * Store a type+offset into a swp_entry_t in an arch-independent format
85 */
swp_entry(unsigned long type,pgoff_t offset)86 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
87 {
88 swp_entry_t ret;
89
90 ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
91 return ret;
92 }
93
94 /*
95 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
96 * arch-independent format
97 */
swp_type(swp_entry_t entry)98 static inline unsigned swp_type(swp_entry_t entry)
99 {
100 return (entry.val >> SWP_TYPE_SHIFT);
101 }
102
103 /*
104 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
105 * arch-independent format
106 */
swp_offset(swp_entry_t entry)107 static inline pgoff_t swp_offset(swp_entry_t entry)
108 {
109 return entry.val & SWP_OFFSET_MASK;
110 }
111
112 /*
113 * This should only be called upon a pfn swap entry to get the PFN stored
114 * in the swap entry. Please refers to is_pfn_swap_entry() for definition
115 * of pfn swap entry.
116 */
swp_offset_pfn(swp_entry_t entry)117 static inline unsigned long swp_offset_pfn(swp_entry_t entry)
118 {
119 VM_BUG_ON(!is_pfn_swap_entry(entry));
120 return swp_offset(entry) & SWP_PFN_MASK;
121 }
122
123 /* check whether a pte points to a swap entry */
is_swap_pte(pte_t pte)124 static inline int is_swap_pte(pte_t pte)
125 {
126 return !pte_none(pte) && !pte_present(pte);
127 }
128
129 /*
130 * Convert the arch-dependent pte representation of a swp_entry_t into an
131 * arch-independent swp_entry_t.
132 */
pte_to_swp_entry(pte_t pte)133 static inline swp_entry_t pte_to_swp_entry(pte_t pte)
134 {
135 swp_entry_t arch_entry;
136
137 pte = pte_swp_clear_flags(pte);
138 arch_entry = __pte_to_swp_entry(pte);
139 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
140 }
141
142 /*
143 * Convert the arch-independent representation of a swp_entry_t into the
144 * arch-dependent pte representation.
145 */
swp_entry_to_pte(swp_entry_t entry)146 static inline pte_t swp_entry_to_pte(swp_entry_t entry)
147 {
148 swp_entry_t arch_entry;
149
150 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
151 return __swp_entry_to_pte(arch_entry);
152 }
153
radix_to_swp_entry(void * arg)154 static inline swp_entry_t radix_to_swp_entry(void *arg)
155 {
156 swp_entry_t entry;
157
158 entry.val = xa_to_value(arg);
159 return entry;
160 }
161
swp_to_radix_entry(swp_entry_t entry)162 static inline void *swp_to_radix_entry(swp_entry_t entry)
163 {
164 return xa_mk_value(entry.val);
165 }
166
make_swapin_error_entry(struct page * page)167 static inline swp_entry_t make_swapin_error_entry(struct page *page)
168 {
169 return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page));
170 }
171
is_swapin_error_entry(swp_entry_t entry)172 static inline int is_swapin_error_entry(swp_entry_t entry)
173 {
174 return swp_type(entry) == SWP_SWAPIN_ERROR;
175 }
176
177 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
make_readable_device_private_entry(pgoff_t offset)178 static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
179 {
180 return swp_entry(SWP_DEVICE_READ, offset);
181 }
182
make_writable_device_private_entry(pgoff_t offset)183 static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
184 {
185 return swp_entry(SWP_DEVICE_WRITE, offset);
186 }
187
is_device_private_entry(swp_entry_t entry)188 static inline bool is_device_private_entry(swp_entry_t entry)
189 {
190 int type = swp_type(entry);
191 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
192 }
193
is_writable_device_private_entry(swp_entry_t entry)194 static inline bool is_writable_device_private_entry(swp_entry_t entry)
195 {
196 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
197 }
198
make_readable_device_exclusive_entry(pgoff_t offset)199 static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
200 {
201 return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
202 }
203
make_writable_device_exclusive_entry(pgoff_t offset)204 static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
205 {
206 return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
207 }
208
is_device_exclusive_entry(swp_entry_t entry)209 static inline bool is_device_exclusive_entry(swp_entry_t entry)
210 {
211 return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
212 swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
213 }
214
is_writable_device_exclusive_entry(swp_entry_t entry)215 static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
216 {
217 return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
218 }
219 #else /* CONFIG_DEVICE_PRIVATE */
make_readable_device_private_entry(pgoff_t offset)220 static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
221 {
222 return swp_entry(0, 0);
223 }
224
make_writable_device_private_entry(pgoff_t offset)225 static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
226 {
227 return swp_entry(0, 0);
228 }
229
is_device_private_entry(swp_entry_t entry)230 static inline bool is_device_private_entry(swp_entry_t entry)
231 {
232 return false;
233 }
234
is_writable_device_private_entry(swp_entry_t entry)235 static inline bool is_writable_device_private_entry(swp_entry_t entry)
236 {
237 return false;
238 }
239
make_readable_device_exclusive_entry(pgoff_t offset)240 static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
241 {
242 return swp_entry(0, 0);
243 }
244
make_writable_device_exclusive_entry(pgoff_t offset)245 static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
246 {
247 return swp_entry(0, 0);
248 }
249
is_device_exclusive_entry(swp_entry_t entry)250 static inline bool is_device_exclusive_entry(swp_entry_t entry)
251 {
252 return false;
253 }
254
is_writable_device_exclusive_entry(swp_entry_t entry)255 static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
256 {
257 return false;
258 }
259 #endif /* CONFIG_DEVICE_PRIVATE */
260
261 #ifdef CONFIG_MIGRATION
is_migration_entry(swp_entry_t entry)262 static inline int is_migration_entry(swp_entry_t entry)
263 {
264 return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
265 swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE ||
266 swp_type(entry) == SWP_MIGRATION_WRITE);
267 }
268
is_writable_migration_entry(swp_entry_t entry)269 static inline int is_writable_migration_entry(swp_entry_t entry)
270 {
271 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
272 }
273
is_readable_migration_entry(swp_entry_t entry)274 static inline int is_readable_migration_entry(swp_entry_t entry)
275 {
276 return unlikely(swp_type(entry) == SWP_MIGRATION_READ);
277 }
278
is_readable_exclusive_migration_entry(swp_entry_t entry)279 static inline int is_readable_exclusive_migration_entry(swp_entry_t entry)
280 {
281 return unlikely(swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE);
282 }
283
make_readable_migration_entry(pgoff_t offset)284 static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
285 {
286 return swp_entry(SWP_MIGRATION_READ, offset);
287 }
288
make_readable_exclusive_migration_entry(pgoff_t offset)289 static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
290 {
291 return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset);
292 }
293
make_writable_migration_entry(pgoff_t offset)294 static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
295 {
296 return swp_entry(SWP_MIGRATION_WRITE, offset);
297 }
298
299 /*
300 * Returns whether the host has large enough swap offset field to support
301 * carrying over pgtable A/D bits for page migrations. The result is
302 * pretty much arch specific.
303 */
migration_entry_supports_ad(void)304 static inline bool migration_entry_supports_ad(void)
305 {
306 #ifdef CONFIG_SWAP
307 return swap_migration_ad_supported;
308 #else /* CONFIG_SWAP */
309 return false;
310 #endif /* CONFIG_SWAP */
311 }
312
make_migration_entry_young(swp_entry_t entry)313 static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
314 {
315 if (migration_entry_supports_ad())
316 return swp_entry(swp_type(entry),
317 swp_offset(entry) | SWP_MIG_YOUNG);
318 return entry;
319 }
320
is_migration_entry_young(swp_entry_t entry)321 static inline bool is_migration_entry_young(swp_entry_t entry)
322 {
323 if (migration_entry_supports_ad())
324 return swp_offset(entry) & SWP_MIG_YOUNG;
325 /* Keep the old behavior of aging page after migration */
326 return false;
327 }
328
make_migration_entry_dirty(swp_entry_t entry)329 static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
330 {
331 if (migration_entry_supports_ad())
332 return swp_entry(swp_type(entry),
333 swp_offset(entry) | SWP_MIG_DIRTY);
334 return entry;
335 }
336
is_migration_entry_dirty(swp_entry_t entry)337 static inline bool is_migration_entry_dirty(swp_entry_t entry)
338 {
339 if (migration_entry_supports_ad())
340 return swp_offset(entry) & SWP_MIG_DIRTY;
341 /* Keep the old behavior of clean page after migration */
342 return false;
343 }
344
345 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
346 spinlock_t *ptl);
347 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
348 unsigned long address);
349 #ifdef CONFIG_HUGETLB_PAGE
350 extern void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl);
351 extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
352 #endif /* CONFIG_HUGETLB_PAGE */
353 #else /* CONFIG_MIGRATION */
make_readable_migration_entry(pgoff_t offset)354 static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
355 {
356 return swp_entry(0, 0);
357 }
358
make_readable_exclusive_migration_entry(pgoff_t offset)359 static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
360 {
361 return swp_entry(0, 0);
362 }
363
make_writable_migration_entry(pgoff_t offset)364 static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
365 {
366 return swp_entry(0, 0);
367 }
368
is_migration_entry(swp_entry_t swp)369 static inline int is_migration_entry(swp_entry_t swp)
370 {
371 return 0;
372 }
373
__migration_entry_wait(struct mm_struct * mm,pte_t * ptep,spinlock_t * ptl)374 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
375 spinlock_t *ptl) { }
migration_entry_wait(struct mm_struct * mm,pmd_t * pmd,unsigned long address)376 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
377 unsigned long address) { }
378 #ifdef CONFIG_HUGETLB_PAGE
__migration_entry_wait_huge(pte_t * ptep,spinlock_t * ptl)379 static inline void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { }
migration_entry_wait_huge(struct vm_area_struct * vma,pte_t * pte)380 static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
381 #endif /* CONFIG_HUGETLB_PAGE */
is_writable_migration_entry(swp_entry_t entry)382 static inline int is_writable_migration_entry(swp_entry_t entry)
383 {
384 return 0;
385 }
is_readable_migration_entry(swp_entry_t entry)386 static inline int is_readable_migration_entry(swp_entry_t entry)
387 {
388 return 0;
389 }
390
make_migration_entry_young(swp_entry_t entry)391 static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
392 {
393 return entry;
394 }
395
is_migration_entry_young(swp_entry_t entry)396 static inline bool is_migration_entry_young(swp_entry_t entry)
397 {
398 return false;
399 }
400
make_migration_entry_dirty(swp_entry_t entry)401 static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
402 {
403 return entry;
404 }
405
is_migration_entry_dirty(swp_entry_t entry)406 static inline bool is_migration_entry_dirty(swp_entry_t entry)
407 {
408 return false;
409 }
410 #endif /* CONFIG_MIGRATION */
411
412 typedef unsigned long pte_marker;
413
414 #define PTE_MARKER_UFFD_WP BIT(0)
415 #define PTE_MARKER_MASK (PTE_MARKER_UFFD_WP)
416
417 #ifdef CONFIG_PTE_MARKER
418
make_pte_marker_entry(pte_marker marker)419 static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
420 {
421 return swp_entry(SWP_PTE_MARKER, marker);
422 }
423
is_pte_marker_entry(swp_entry_t entry)424 static inline bool is_pte_marker_entry(swp_entry_t entry)
425 {
426 return swp_type(entry) == SWP_PTE_MARKER;
427 }
428
pte_marker_get(swp_entry_t entry)429 static inline pte_marker pte_marker_get(swp_entry_t entry)
430 {
431 return swp_offset(entry) & PTE_MARKER_MASK;
432 }
433
is_pte_marker(pte_t pte)434 static inline bool is_pte_marker(pte_t pte)
435 {
436 return is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte));
437 }
438
439 #else /* CONFIG_PTE_MARKER */
440
make_pte_marker_entry(pte_marker marker)441 static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
442 {
443 /* This should never be called if !CONFIG_PTE_MARKER */
444 WARN_ON_ONCE(1);
445 return swp_entry(0, 0);
446 }
447
is_pte_marker_entry(swp_entry_t entry)448 static inline bool is_pte_marker_entry(swp_entry_t entry)
449 {
450 return false;
451 }
452
pte_marker_get(swp_entry_t entry)453 static inline pte_marker pte_marker_get(swp_entry_t entry)
454 {
455 return 0;
456 }
457
is_pte_marker(pte_t pte)458 static inline bool is_pte_marker(pte_t pte)
459 {
460 return false;
461 }
462
463 #endif /* CONFIG_PTE_MARKER */
464
make_pte_marker(pte_marker marker)465 static inline pte_t make_pte_marker(pte_marker marker)
466 {
467 return swp_entry_to_pte(make_pte_marker_entry(marker));
468 }
469
470 /*
471 * This is a special version to check pte_none() just to cover the case when
472 * the pte is a pte marker. It existed because in many cases the pte marker
473 * should be seen as a none pte; it's just that we have stored some information
474 * onto the none pte so it becomes not-none any more.
475 *
476 * It should be used when the pte is file-backed, ram-based and backing
477 * userspace pages, like shmem. It is not needed upon pgtables that do not
478 * support pte markers at all. For example, it's not needed on anonymous
479 * memory, kernel-only memory (including when the system is during-boot),
480 * non-ram based generic file-system. It's fine to be used even there, but the
481 * extra pte marker check will be pure overhead.
482 *
483 * For systems configured with !CONFIG_PTE_MARKER this will be automatically
484 * optimized to pte_none().
485 */
pte_none_mostly(pte_t pte)486 static inline int pte_none_mostly(pte_t pte)
487 {
488 return pte_none(pte) || is_pte_marker(pte);
489 }
490
pfn_swap_entry_to_page(swp_entry_t entry)491 static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
492 {
493 struct page *p = pfn_to_page(swp_offset_pfn(entry));
494
495 /*
496 * Any use of migration entries may only occur while the
497 * corresponding page is locked
498 */
499 BUG_ON(is_migration_entry(entry) && !PageLocked(p));
500
501 return p;
502 }
503
504 /*
505 * A pfn swap entry is a special type of swap entry that always has a pfn stored
506 * in the swap offset. They are used to represent unaddressable device memory
507 * and to restrict access to a page undergoing migration.
508 */
is_pfn_swap_entry(swp_entry_t entry)509 static inline bool is_pfn_swap_entry(swp_entry_t entry)
510 {
511 /* Make sure the swp offset can always store the needed fields */
512 BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
513
514 return is_migration_entry(entry) || is_device_private_entry(entry) ||
515 is_device_exclusive_entry(entry);
516 }
517
518 struct page_vma_mapped_walk;
519
520 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
521 extern int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
522 struct page *page);
523
524 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
525 struct page *new);
526
527 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
528
pmd_to_swp_entry(pmd_t pmd)529 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
530 {
531 swp_entry_t arch_entry;
532
533 if (pmd_swp_soft_dirty(pmd))
534 pmd = pmd_swp_clear_soft_dirty(pmd);
535 if (pmd_swp_uffd_wp(pmd))
536 pmd = pmd_swp_clear_uffd_wp(pmd);
537 arch_entry = __pmd_to_swp_entry(pmd);
538 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
539 }
540
swp_entry_to_pmd(swp_entry_t entry)541 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
542 {
543 swp_entry_t arch_entry;
544
545 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
546 return __swp_entry_to_pmd(arch_entry);
547 }
548
is_pmd_migration_entry(pmd_t pmd)549 static inline int is_pmd_migration_entry(pmd_t pmd)
550 {
551 return is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
552 }
553 #else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
set_pmd_migration_entry(struct page_vma_mapped_walk * pvmw,struct page * page)554 static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
555 struct page *page)
556 {
557 BUILD_BUG();
558 }
559
remove_migration_pmd(struct page_vma_mapped_walk * pvmw,struct page * new)560 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
561 struct page *new)
562 {
563 BUILD_BUG();
564 }
565
pmd_migration_entry_wait(struct mm_struct * m,pmd_t * p)566 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
567
pmd_to_swp_entry(pmd_t pmd)568 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
569 {
570 return swp_entry(0, 0);
571 }
572
swp_entry_to_pmd(swp_entry_t entry)573 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
574 {
575 return __pmd(0);
576 }
577
is_pmd_migration_entry(pmd_t pmd)578 static inline int is_pmd_migration_entry(pmd_t pmd)
579 {
580 return 0;
581 }
582 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
583
584 #ifdef CONFIG_MEMORY_FAILURE
585
586 extern atomic_long_t num_poisoned_pages __read_mostly;
587
588 /*
589 * Support for hardware poisoned pages
590 */
make_hwpoison_entry(struct page * page)591 static inline swp_entry_t make_hwpoison_entry(struct page *page)
592 {
593 BUG_ON(!PageLocked(page));
594 return swp_entry(SWP_HWPOISON, page_to_pfn(page));
595 }
596
is_hwpoison_entry(swp_entry_t entry)597 static inline int is_hwpoison_entry(swp_entry_t entry)
598 {
599 return swp_type(entry) == SWP_HWPOISON;
600 }
601
num_poisoned_pages_inc(void)602 static inline void num_poisoned_pages_inc(void)
603 {
604 atomic_long_inc(&num_poisoned_pages);
605 }
606
num_poisoned_pages_sub(long i)607 static inline void num_poisoned_pages_sub(long i)
608 {
609 atomic_long_sub(i, &num_poisoned_pages);
610 }
611
612 #else /* CONFIG_MEMORY_FAILURE */
613
make_hwpoison_entry(struct page * page)614 static inline swp_entry_t make_hwpoison_entry(struct page *page)
615 {
616 return swp_entry(0, 0);
617 }
618
is_hwpoison_entry(swp_entry_t swp)619 static inline int is_hwpoison_entry(swp_entry_t swp)
620 {
621 return 0;
622 }
623
num_poisoned_pages_inc(void)624 static inline void num_poisoned_pages_inc(void)
625 {
626 }
627
num_poisoned_pages_sub(long i)628 static inline void num_poisoned_pages_sub(long i)
629 {
630 }
631 #endif /* CONFIG_MEMORY_FAILURE */
632
non_swap_entry(swp_entry_t entry)633 static inline int non_swap_entry(swp_entry_t entry)
634 {
635 return swp_type(entry) >= MAX_SWAPFILES;
636 }
637
638 #endif /* CONFIG_MMU */
639 #endif /* _LINUX_SWAPOPS_H */
640