1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MM_TYPES_H
3 #define _LINUX_MM_TYPES_H
4
5 #include <linux/mm_types_task.h>
6
7 #include <linux/auxvec.h>
8 #include <linux/kref.h>
9 #include <linux/list.h>
10 #include <linux/spinlock.h>
11 #include <linux/rbtree.h>
12 #include <linux/maple_tree.h>
13 #include <linux/rwsem.h>
14 #include <linux/completion.h>
15 #include <linux/cpumask.h>
16 #include <linux/uprobes.h>
17 #include <linux/rcupdate.h>
18 #include <linux/page-flags-layout.h>
19 #include <linux/workqueue.h>
20 #include <linux/seqlock.h>
21 #include <linux/percpu_counter.h>
22 #include <linux/android_kabi.h>
23
24 #include <asm/mmu.h>
25
26 #ifndef AT_VECTOR_SIZE_ARCH
27 #define AT_VECTOR_SIZE_ARCH 0
28 #endif
29 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
30
31 #define INIT_PASID 0
32
33 struct address_space;
34 struct mem_cgroup;
35
36 /*
37 * Each physical page in the system has a struct page associated with
38 * it to keep track of whatever it is we are using the page for at the
39 * moment. Note that we have no way to track which tasks are using
40 * a page, though if it is a pagecache page, rmap structures can tell us
41 * who is mapping it.
42 *
43 * If you allocate the page using alloc_pages(), you can use some of the
44 * space in struct page for your own purposes. The five words in the main
45 * union are available, except for bit 0 of the first word which must be
46 * kept clear. Many users use this word to store a pointer to an object
47 * which is guaranteed to be aligned. If you use the same storage as
48 * page->mapping, you must restore it to NULL before freeing the page.
49 *
50 * If your page will not be mapped to userspace, you can also use the four
51 * bytes in the mapcount union, but you must call page_mapcount_reset()
52 * before freeing it.
53 *
54 * If you want to use the refcount field, it must be used in such a way
55 * that other CPUs temporarily incrementing and then decrementing the
56 * refcount does not cause problems. On receiving the page from
57 * alloc_pages(), the refcount will be positive.
58 *
59 * If you allocate pages of order > 0, you can use some of the fields
60 * in each subpage, but you may need to restore some of their values
61 * afterwards.
62 *
63 * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
64 * That requires that freelist & counters in struct slab be adjacent and
65 * double-word aligned. Because struct slab currently just reinterprets the
66 * bits of struct page, we align all struct pages to double-word boundaries,
67 * and ensure that 'freelist' is aligned within struct slab.
68 */
69 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
70 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
71 #else
72 #define _struct_page_alignment __aligned(sizeof(unsigned long))
73 #endif
74
75 struct page {
76 unsigned long flags; /* Atomic flags, some possibly
77 * updated asynchronously */
78 /*
79 * Five words (20/40 bytes) are available in this union.
80 * WARNING: bit 0 of the first word is used for PageTail(). That
81 * means the other users of this union MUST NOT use the bit to
82 * avoid collision and false-positive PageTail().
83 */
84 union {
85 struct { /* Page cache and anonymous pages */
86 /**
87 * @lru: Pageout list, eg. active_list protected by
88 * lruvec->lru_lock. Sometimes used as a generic list
89 * by the page owner.
90 */
91 union {
92 struct list_head lru;
93
94 /* Or, for the Unevictable "LRU list" slot */
95 struct {
96 /* Always even, to negate PageTail */
97 void *__filler;
98 /* Count page's or folio's mlocks */
99 unsigned int mlock_count;
100 };
101
102 /* Or, free page */
103 struct list_head buddy_list;
104 struct list_head pcp_list;
105 };
106 /* See page-flags.h for PAGE_MAPPING_FLAGS */
107 struct address_space *mapping;
108 union {
109 pgoff_t index; /* Our offset within mapping. */
110 unsigned long share; /* share count for fsdax */
111 };
112 /**
113 * @private: Mapping-private opaque data.
114 * Usually used for buffer_heads if PagePrivate.
115 * Used for swp_entry_t if PageSwapCache.
116 * Indicates order in the buddy system if PageBuddy.
117 */
118 unsigned long private;
119 };
120 struct { /* page_pool used by netstack */
121 /**
122 * @pp_magic: magic value to avoid recycling non
123 * page_pool allocated pages.
124 */
125 unsigned long pp_magic;
126 struct page_pool *pp;
127 unsigned long _pp_mapping_pad;
128 unsigned long dma_addr;
129 union {
130 /**
131 * dma_addr_upper: might require a 64-bit
132 * value on 32-bit architectures.
133 */
134 unsigned long dma_addr_upper;
135 /**
136 * For frag page support, not supported in
137 * 32-bit architectures with 64-bit DMA.
138 */
139 atomic_long_t pp_frag_count;
140 };
141 };
142 struct { /* Tail pages of compound page */
143 unsigned long compound_head; /* Bit zero is set */
144 };
145 struct { /* ZONE_DEVICE pages */
146 /** @pgmap: Points to the hosting device page map. */
147 struct dev_pagemap *pgmap;
148 void *zone_device_data;
149 /*
150 * ZONE_DEVICE private pages are counted as being
151 * mapped so the next 3 words hold the mapping, index,
152 * and private fields from the source anonymous or
153 * page cache page while the page is migrated to device
154 * private memory.
155 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
156 * use the mapping, index, and private fields when
157 * pmem backed DAX files are mapped.
158 */
159 };
160
161 /** @rcu_head: You can use this to free a page by RCU. */
162 struct rcu_head rcu_head;
163 };
164
165 union { /* This union is 4 bytes in size. */
166 /*
167 * If the page can be mapped to userspace, encodes the number
168 * of times this page is referenced by a page table.
169 */
170 atomic_t _mapcount;
171
172 /*
173 * If the page is neither PageSlab nor mappable to userspace,
174 * the value stored here may help determine what this page
175 * is used for. See page-flags.h for a list of page types
176 * which are currently stored here.
177 */
178 unsigned int page_type;
179 };
180
181 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
182 atomic_t _refcount;
183
184 #ifdef CONFIG_MEMCG
185 unsigned long memcg_data;
186 #endif
187
188 /*
189 * On machines where all RAM is mapped into kernel address space,
190 * we can simply calculate the virtual address. On machines with
191 * highmem some memory is mapped into kernel virtual memory
192 * dynamically, so we need a place to store that address.
193 * Note that this field could be 16 bits on x86 ... ;)
194 *
195 * Architectures with slow multiplication can define
196 * WANT_PAGE_VIRTUAL in asm/page.h
197 */
198 #if defined(WANT_PAGE_VIRTUAL)
199 void *virtual; /* Kernel virtual address (NULL if
200 not kmapped, ie. highmem) */
201 #endif /* WANT_PAGE_VIRTUAL */
202
203 #ifdef CONFIG_KMSAN
204 /*
205 * KMSAN metadata for this page:
206 * - shadow page: every bit indicates whether the corresponding
207 * bit of the original page is initialized (0) or not (1);
208 * - origin page: every 4 bytes contain an id of the stack trace
209 * where the uninitialized value was created.
210 */
211 struct page *kmsan_shadow;
212 struct page *kmsan_origin;
213 #endif
214
215 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
216 int _last_cpupid;
217 #endif
218 } _struct_page_alignment;
219
220 /*
221 * struct encoded_page - a nonexistent type marking this pointer
222 *
223 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but
224 * with the low bits of the pointer indicating extra context-dependent
225 * information. Only used in mmu_gather handling, and this acts as a type
226 * system check on that use.
227 *
228 * We only really have two guaranteed bits in general, although you could
229 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
230 * for more.
231 *
232 * Use the supplied helper functions to endcode/decode the pointer and bits.
233 */
234 struct encoded_page;
235
236 #define ENCODED_PAGE_BITS 3ul
237
238 /* Perform rmap removal after we have flushed the TLB. */
239 #define ENCODED_PAGE_BIT_DELAY_RMAP 1ul
240
241 /*
242 * The next item in an encoded_page array is the "nr_pages" argument, specifying
243 * the number of consecutive pages starting from this page, that all belong to
244 * the same folio. For example, "nr_pages" corresponds to the number of folio
245 * references that must be dropped. If this bit is not set, "nr_pages" is
246 * implicitly 1.
247 */
248 #define ENCODED_PAGE_BIT_NR_PAGES_NEXT 2ul
249
encode_page(struct page * page,unsigned long flags)250 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
251 {
252 BUILD_BUG_ON(flags > ENCODED_PAGE_BITS);
253 return (struct encoded_page *)(flags | (unsigned long)page);
254 }
255
encoded_page_flags(struct encoded_page * page)256 static inline unsigned long encoded_page_flags(struct encoded_page *page)
257 {
258 return ENCODED_PAGE_BITS & (unsigned long)page;
259 }
260
encoded_page_ptr(struct encoded_page * page)261 static inline struct page *encoded_page_ptr(struct encoded_page *page)
262 {
263 return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page);
264 }
265
encode_nr_pages(unsigned long nr)266 static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr)
267 {
268 VM_WARN_ON_ONCE((nr << 2) >> 2 != nr);
269 return (struct encoded_page *)(nr << 2);
270 }
271
encoded_nr_pages(struct encoded_page * page)272 static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page)
273 {
274 return ((unsigned long)page) >> 2;
275 }
276
277 /*
278 * A swap entry has to fit into a "unsigned long", as the entry is hidden
279 * in the "index" field of the swapper address space.
280 */
281 typedef struct {
282 unsigned long val;
283 } swp_entry_t;
284
285 /**
286 * struct folio - Represents a contiguous set of bytes.
287 * @flags: Identical to the page flags.
288 * @lru: Least Recently Used list; tracks how recently this folio was used.
289 * @mlock_count: Number of times this folio has been pinned by mlock().
290 * @mapping: The file this page belongs to, or refers to the anon_vma for
291 * anonymous memory.
292 * @index: Offset within the file, in units of pages. For anonymous memory,
293 * this is the index from the beginning of the mmap.
294 * @private: Filesystem per-folio data (see folio_attach_private()).
295 * @swap: Used for swp_entry_t if folio_test_swapcache().
296 * @_mapcount: Do not access this member directly. Use folio_mapcount() to
297 * find out how many times this folio is mapped by userspace.
298 * @_refcount: Do not access this member directly. Use folio_ref_count()
299 * to find how many references there are to this folio.
300 * @memcg_data: Memory Control Group data.
301 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
302 * @_nr_pages_mapped: Do not use directly, call folio_mapcount().
303 * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
304 * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
305 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
306 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
307 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
308 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
309 * @_deferred_list: Folios to be split under memory pressure.
310 *
311 * A folio is a physically, virtually and logically contiguous set
312 * of bytes. It is a power-of-two in size, and it is aligned to that
313 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is
314 * in the page cache, it is at a file offset which is a multiple of that
315 * power-of-two. It may be mapped into userspace at an address which is
316 * at an arbitrary page offset, but its kernel virtual address is aligned
317 * to its size.
318 */
319 struct folio {
320 /* private: don't document the anon union */
321 union {
322 struct {
323 /* public: */
324 unsigned long flags;
325 union {
326 struct list_head lru;
327 /* private: avoid cluttering the output */
328 struct {
329 void *__filler;
330 /* public: */
331 unsigned int mlock_count;
332 /* private: */
333 };
334 /* public: */
335 };
336 struct address_space *mapping;
337 pgoff_t index;
338 union {
339 void *private;
340 swp_entry_t swap;
341 };
342 atomic_t _mapcount;
343 atomic_t _refcount;
344 #ifdef CONFIG_MEMCG
345 unsigned long memcg_data;
346 #endif
347 /* private: the union with struct page is transitional */
348 };
349 struct page page;
350 };
351 union {
352 struct {
353 unsigned long _flags_1;
354 unsigned long _head_1;
355 /* public: */
356 atomic_t _entire_mapcount;
357 atomic_t _nr_pages_mapped;
358 atomic_t _pincount;
359 #ifdef CONFIG_64BIT
360 unsigned int __padding;
361 unsigned int _folio_nr_pages;
362 #endif
363 union {
364 unsigned long _private_1;
365 unsigned long *_dst_ul;
366 struct page **_dst_pp;
367 };
368 /* private: the union with struct page is transitional */
369 };
370 struct page __page_1;
371 };
372 union {
373 struct {
374 unsigned long _flags_2;
375 unsigned long _head_2;
376 /* public: */
377 void *_hugetlb_subpool;
378 void *_hugetlb_cgroup;
379 void *_hugetlb_cgroup_rsvd;
380 void *_hugetlb_hwpoison;
381 /* private: the union with struct page is transitional */
382 };
383 struct {
384 unsigned long _flags_2a;
385 unsigned long _head_2a;
386 /* public: */
387 struct list_head _deferred_list;
388 /* private: the union with struct page is transitional */
389 };
390 struct page __page_2;
391 };
392 };
393
394 #define FOLIO_MATCH(pg, fl) \
395 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
396 FOLIO_MATCH(flags, flags);
397 FOLIO_MATCH(lru, lru);
398 FOLIO_MATCH(mapping, mapping);
399 FOLIO_MATCH(compound_head, lru);
400 FOLIO_MATCH(index, index);
401 FOLIO_MATCH(private, private);
402 FOLIO_MATCH(_mapcount, _mapcount);
403 FOLIO_MATCH(_refcount, _refcount);
404 #ifdef CONFIG_MEMCG
405 FOLIO_MATCH(memcg_data, memcg_data);
406 #endif
407 #undef FOLIO_MATCH
408 #define FOLIO_MATCH(pg, fl) \
409 static_assert(offsetof(struct folio, fl) == \
410 offsetof(struct page, pg) + sizeof(struct page))
411 FOLIO_MATCH(flags, _flags_1);
412 FOLIO_MATCH(compound_head, _head_1);
413 FOLIO_MATCH(private, _private_1);
414 #undef FOLIO_MATCH
415 #define FOLIO_MATCH(pg, fl) \
416 static_assert(offsetof(struct folio, fl) == \
417 offsetof(struct page, pg) + 2 * sizeof(struct page))
418 FOLIO_MATCH(flags, _flags_2);
419 FOLIO_MATCH(compound_head, _head_2);
420 FOLIO_MATCH(flags, _flags_2a);
421 FOLIO_MATCH(compound_head, _head_2a);
422 #undef FOLIO_MATCH
423
424 /**
425 * struct ptdesc - Memory descriptor for page tables.
426 * @__page_flags: Same as page flags. Unused for page tables.
427 * @pt_rcu_head: For freeing page table pages.
428 * @pt_list: List of used page tables. Used for s390 and x86.
429 * @_pt_pad_1: Padding that aliases with page's compound head.
430 * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs.
431 * @__page_mapping: Aliases with page->mapping. Unused for page tables.
432 * @pt_mm: Used for x86 pgds.
433 * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
434 * @_pt_pad_2: Padding to ensure proper alignment.
435 * @ptl: Lock for the page table.
436 * @__page_type: Same as page->page_type. Unused for page tables.
437 * @_refcount: Same as page refcount. Used for s390 page tables.
438 * @pt_memcg_data: Memcg data. Tracked for page tables here.
439 *
440 * This struct overlays struct page for now. Do not modify without a good
441 * understanding of the issues.
442 */
443 struct ptdesc {
444 unsigned long __page_flags;
445
446 union {
447 struct rcu_head pt_rcu_head;
448 struct list_head pt_list;
449 struct {
450 unsigned long _pt_pad_1;
451 pgtable_t pmd_huge_pte;
452 };
453 };
454 unsigned long __page_mapping;
455
456 union {
457 struct mm_struct *pt_mm;
458 atomic_t pt_frag_refcount;
459 };
460
461 union {
462 unsigned long _pt_pad_2;
463 #if ALLOC_SPLIT_PTLOCKS
464 spinlock_t *ptl;
465 #else
466 spinlock_t ptl;
467 #endif
468 };
469 unsigned int __page_type;
470 atomic_t _refcount;
471 #ifdef CONFIG_MEMCG
472 unsigned long pt_memcg_data;
473 #endif
474 };
475
476 #define TABLE_MATCH(pg, pt) \
477 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
478 TABLE_MATCH(flags, __page_flags);
479 TABLE_MATCH(compound_head, pt_list);
480 TABLE_MATCH(compound_head, _pt_pad_1);
481 TABLE_MATCH(mapping, __page_mapping);
482 TABLE_MATCH(rcu_head, pt_rcu_head);
483 TABLE_MATCH(page_type, __page_type);
484 TABLE_MATCH(_refcount, _refcount);
485 #ifdef CONFIG_MEMCG
486 TABLE_MATCH(memcg_data, pt_memcg_data);
487 #endif
488 #undef TABLE_MATCH
489 static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
490
491 #define ptdesc_page(pt) (_Generic((pt), \
492 const struct ptdesc *: (const struct page *)(pt), \
493 struct ptdesc *: (struct page *)(pt)))
494
495 #define ptdesc_folio(pt) (_Generic((pt), \
496 const struct ptdesc *: (const struct folio *)(pt), \
497 struct ptdesc *: (struct folio *)(pt)))
498
499 #define page_ptdesc(p) (_Generic((p), \
500 const struct page *: (const struct ptdesc *)(p), \
501 struct page *: (struct ptdesc *)(p)))
502
503 /*
504 * Used for sizing the vmemmap region on some architectures
505 */
506 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
507
508 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
509 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
510
511 /*
512 * page_private can be used on tail pages. However, PagePrivate is only
513 * checked by the VM on the head page. So page_private on the tail pages
514 * should be used for data that's ancillary to the head page (eg attaching
515 * buffer heads to tail pages after attaching buffer heads to the head page)
516 */
517 #define page_private(page) ((page)->private)
518
set_page_private(struct page * page,unsigned long private)519 static inline void set_page_private(struct page *page, unsigned long private)
520 {
521 page->private = private;
522 }
523
folio_get_private(struct folio * folio)524 static inline void *folio_get_private(struct folio *folio)
525 {
526 return folio->private;
527 }
528
529 struct page_frag_cache {
530 void * va;
531 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
532 __u16 offset;
533 __u16 size;
534 #else
535 __u32 offset;
536 #endif
537 /* we maintain a pagecount bias, so that we dont dirty cache line
538 * containing page->_refcount every time we allocate a fragment.
539 */
540 unsigned int pagecnt_bias;
541 bool pfmemalloc;
542 };
543
544 typedef unsigned long vm_flags_t;
545
546 /*
547 * A region containing a mapping of a non-memory backed file under NOMMU
548 * conditions. These are held in a global tree and are pinned by the VMAs that
549 * map parts of them.
550 */
551 struct vm_region {
552 struct rb_node vm_rb; /* link in global region tree */
553 vm_flags_t vm_flags; /* VMA vm_flags */
554 unsigned long vm_start; /* start address of region */
555 unsigned long vm_end; /* region initialised to here */
556 unsigned long vm_top; /* region allocated to here */
557 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
558 struct file *vm_file; /* the backing file or NULL */
559
560 int vm_usage; /* region usage count (access under nommu_region_sem) */
561 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
562 * this region */
563 };
564
565 #ifdef CONFIG_USERFAULTFD
566 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
567 struct vm_userfaultfd_ctx {
568 struct userfaultfd_ctx *ctx;
569 };
570 #else /* CONFIG_USERFAULTFD */
571 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
572 struct vm_userfaultfd_ctx {};
573 #endif /* CONFIG_USERFAULTFD */
574
575 struct anon_vma_name {
576 struct kref kref;
577 /* The name needs to be at the end because it is dynamically sized. */
578 char name[];
579 };
580
581 struct vma_lock {
582 struct rw_semaphore lock;
583 };
584
585 struct vma_numab_state {
586 unsigned long next_scan;
587 unsigned long next_pid_reset;
588 unsigned long access_pids[2];
589 };
590
591 /*
592 * This struct describes a virtual memory area. There is one of these
593 * per VM-area/task. A VM area is any part of the process virtual memory
594 * space that has a special rule for the page-fault handlers (ie a shared
595 * library, the executable area etc).
596 */
597 struct vm_area_struct {
598 /* The first cache line has the info for VMA tree walking. */
599
600 union {
601 struct {
602 /* VMA covers [vm_start; vm_end) addresses within mm */
603 unsigned long vm_start;
604 unsigned long vm_end;
605 };
606 #ifdef CONFIG_PER_VMA_LOCK
607 struct rcu_head vm_rcu; /* Used for deferred freeing. */
608 #endif
609 };
610
611 struct mm_struct *vm_mm; /* The address space we belong to. */
612 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
613
614 /*
615 * Flags, see mm.h.
616 * To modify use vm_flags_{init|reset|set|clear|mod} functions.
617 */
618 union {
619 const vm_flags_t vm_flags;
620 vm_flags_t __private __vm_flags;
621 };
622
623 #ifdef CONFIG_PER_VMA_LOCK
624 /* Flag to indicate areas detached from the mm->mm_mt tree */
625 bool detached;
626
627 /*
628 * Can only be written (using WRITE_ONCE()) while holding both:
629 * - mmap_lock (in write mode)
630 * - vm_lock->lock (in write mode)
631 * Can be read reliably while holding one of:
632 * - mmap_lock (in read or write mode)
633 * - vm_lock->lock (in read or write mode)
634 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout
635 * while holding nothing (except RCU to keep the VMA struct allocated).
636 *
637 * This sequence counter is explicitly allowed to overflow; sequence
638 * counter reuse can only lead to occasional unnecessary use of the
639 * slowpath.
640 */
641 int vm_lock_seq;
642 struct vma_lock *vm_lock;
643 #endif
644
645 /*
646 * For areas with an address space and backing store,
647 * linkage into the address_space->i_mmap interval tree.
648 *
649 */
650 struct {
651 struct rb_node rb;
652 unsigned long rb_subtree_last;
653 } shared;
654
655 /*
656 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
657 * list, after a COW of one of the file pages. A MAP_SHARED vma
658 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
659 * or brk vma (with NULL file) can only be in an anon_vma list.
660 */
661 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
662 * page_table_lock */
663 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
664
665 /* Function pointers to deal with this struct. */
666 const struct vm_operations_struct *vm_ops;
667
668 /* Information about our backing store: */
669 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
670 units */
671 struct file * vm_file; /* File we map to (can be NULL). */
672 void * vm_private_data; /* was vm_pte (shared mem) */
673
674 #ifdef CONFIG_ANON_VMA_NAME
675 /*
676 * For private and shared anonymous mappings, a pointer to a null
677 * terminated string containing the name given to the vma, or NULL if
678 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
679 */
680 struct anon_vma_name *anon_name;
681 #endif
682 #ifdef CONFIG_SWAP
683 atomic_long_t swap_readahead_info;
684 #endif
685 #ifndef CONFIG_MMU
686 struct vm_region *vm_region; /* NOMMU mapping region */
687 #endif
688 #ifdef CONFIG_NUMA
689 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
690 #endif
691 #ifdef CONFIG_NUMA_BALANCING
692 struct vma_numab_state *numab_state; /* NUMA Balancing state */
693 #endif
694 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
695
696 ANDROID_KABI_RESERVE(1);
697 ANDROID_KABI_RESERVE(2);
698 ANDROID_KABI_RESERVE(3);
699 ANDROID_KABI_RESERVE(4);
700 } __randomize_layout;
701
702 #ifdef CONFIG_SCHED_MM_CID
703 struct mm_cid {
704 u64 time;
705 int cid;
706 };
707 #endif
708
709 struct kioctx_table;
710 struct mm_struct {
711 struct {
712 /*
713 * Fields which are often written to are placed in a separate
714 * cache line.
715 */
716 struct {
717 /**
718 * @mm_count: The number of references to &struct
719 * mm_struct (@mm_users count as 1).
720 *
721 * Use mmgrab()/mmdrop() to modify. When this drops to
722 * 0, the &struct mm_struct is freed.
723 */
724 atomic_t mm_count;
725 } ____cacheline_aligned_in_smp;
726
727 struct maple_tree mm_mt;
728 #ifdef CONFIG_MMU
729 unsigned long (*get_unmapped_area) (struct file *filp,
730 unsigned long addr, unsigned long len,
731 unsigned long pgoff, unsigned long flags);
732 #endif
733 unsigned long mmap_base; /* base of mmap area */
734 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
735 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
736 /* Base addresses for compatible mmap() */
737 unsigned long mmap_compat_base;
738 unsigned long mmap_compat_legacy_base;
739 #endif
740 unsigned long task_size; /* size of task vm space */
741 pgd_t * pgd;
742
743 #ifdef CONFIG_MEMBARRIER
744 /**
745 * @membarrier_state: Flags controlling membarrier behavior.
746 *
747 * This field is close to @pgd to hopefully fit in the same
748 * cache-line, which needs to be touched by switch_mm().
749 */
750 atomic_t membarrier_state;
751 #endif
752
753 /**
754 * @mm_users: The number of users including userspace.
755 *
756 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
757 * drops to 0 (i.e. when the task exits and there are no other
758 * temporary reference holders), we also release a reference on
759 * @mm_count (which may then free the &struct mm_struct if
760 * @mm_count also drops to 0).
761 */
762 atomic_t mm_users;
763
764 #ifdef CONFIG_SCHED_MM_CID
765 /**
766 * @pcpu_cid: Per-cpu current cid.
767 *
768 * Keep track of the currently allocated mm_cid for each cpu.
769 * The per-cpu mm_cid values are serialized by their respective
770 * runqueue locks.
771 */
772 struct mm_cid __percpu *pcpu_cid;
773 /*
774 * @mm_cid_next_scan: Next mm_cid scan (in jiffies).
775 *
776 * When the next mm_cid scan is due (in jiffies).
777 */
778 unsigned long mm_cid_next_scan;
779 #endif
780 #ifdef CONFIG_MMU
781 atomic_long_t pgtables_bytes; /* size of all page tables */
782 #endif
783 int map_count; /* number of VMAs */
784
785 spinlock_t page_table_lock; /* Protects page tables and some
786 * counters
787 */
788 /*
789 * With some kernel config, the current mmap_lock's offset
790 * inside 'mm_struct' is at 0x120, which is very optimal, as
791 * its two hot fields 'count' and 'owner' sit in 2 different
792 * cachelines, and when mmap_lock is highly contended, both
793 * of the 2 fields will be accessed frequently, current layout
794 * will help to reduce cache bouncing.
795 *
796 * So please be careful with adding new fields before
797 * mmap_lock, which can easily push the 2 fields into one
798 * cacheline.
799 */
800 struct rw_semaphore mmap_lock;
801
802 struct list_head mmlist; /* List of maybe swapped mm's. These
803 * are globally strung together off
804 * init_mm.mmlist, and are protected
805 * by mmlist_lock
806 */
807 #ifdef CONFIG_PER_VMA_LOCK
808 /*
809 * This field has lock-like semantics, meaning it is sometimes
810 * accessed with ACQUIRE/RELEASE semantics.
811 * Roughly speaking, incrementing the sequence number is
812 * equivalent to releasing locks on VMAs; reading the sequence
813 * number can be part of taking a read lock on a VMA.
814 *
815 * Can be modified under write mmap_lock using RELEASE
816 * semantics.
817 * Can be read with no other protection when holding write
818 * mmap_lock.
819 * Can be read with ACQUIRE semantics if not holding write
820 * mmap_lock.
821 */
822 int mm_lock_seq;
823 #endif
824
825
826 unsigned long hiwater_rss; /* High-watermark of RSS usage */
827 unsigned long hiwater_vm; /* High-water virtual memory usage */
828
829 unsigned long total_vm; /* Total pages mapped */
830 unsigned long locked_vm; /* Pages that have PG_mlocked set */
831 atomic64_t pinned_vm; /* Refcount permanently increased */
832 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
833 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
834 unsigned long stack_vm; /* VM_STACK */
835 unsigned long def_flags;
836
837 /**
838 * @write_protect_seq: Locked when any thread is write
839 * protecting pages mapped by this mm to enforce a later COW,
840 * for instance during page table copying for fork().
841 */
842 seqcount_t write_protect_seq;
843
844 spinlock_t arg_lock; /* protect the below fields */
845
846 unsigned long start_code, end_code, start_data, end_data;
847 unsigned long start_brk, brk, start_stack;
848 unsigned long arg_start, arg_end, env_start, env_end;
849
850 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
851
852 struct percpu_counter rss_stat[NR_MM_COUNTERS];
853
854 struct linux_binfmt *binfmt;
855
856 /* Architecture-specific MM context */
857 mm_context_t context;
858
859 unsigned long flags; /* Must use atomic bitops to access */
860
861 #ifdef CONFIG_AIO
862 spinlock_t ioctx_lock;
863 struct kioctx_table __rcu *ioctx_table;
864 #endif
865 #ifdef CONFIG_MEMCG
866 /*
867 * "owner" points to a task that is regarded as the canonical
868 * user/owner of this mm. All of the following must be true in
869 * order for it to be changed:
870 *
871 * current == mm->owner
872 * current->mm != mm
873 * new_owner->mm == mm
874 * new_owner->alloc_lock is held
875 */
876 struct task_struct __rcu *owner;
877 #endif
878 struct user_namespace *user_ns;
879
880 /* store ref to file /proc/<pid>/exe symlink points to */
881 struct file __rcu *exe_file;
882 #ifdef CONFIG_MMU_NOTIFIER
883 struct mmu_notifier_subscriptions *notifier_subscriptions;
884 #endif
885 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
886 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
887 #endif
888 #ifdef CONFIG_NUMA_BALANCING
889 /*
890 * numa_next_scan is the next time that PTEs will be remapped
891 * PROT_NONE to trigger NUMA hinting faults; such faults gather
892 * statistics and migrate pages to new nodes if necessary.
893 */
894 unsigned long numa_next_scan;
895
896 /* Restart point for scanning and remapping PTEs. */
897 unsigned long numa_scan_offset;
898
899 /* numa_scan_seq prevents two threads remapping PTEs. */
900 int numa_scan_seq;
901 #endif
902 /*
903 * An operation with batched TLB flushing is going on. Anything
904 * that can move process memory needs to flush the TLB when
905 * moving a PROT_NONE mapped page.
906 */
907 atomic_t tlb_flush_pending;
908 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
909 /* See flush_tlb_batched_pending() */
910 atomic_t tlb_flush_batched;
911 #endif
912 struct uprobes_state uprobes_state;
913 #ifdef CONFIG_PREEMPT_RT
914 struct rcu_head delayed_drop;
915 #endif
916 #ifdef CONFIG_HUGETLB_PAGE
917 atomic_long_t hugetlb_usage;
918 #endif
919 struct work_struct async_put_work;
920
921 #ifdef CONFIG_IOMMU_SVA
922 u32 pasid;
923 #endif
924 #ifdef CONFIG_KSM
925 /*
926 * Represent how many pages of this process are involved in KSM
927 * merging (not including ksm_zero_pages).
928 */
929 unsigned long ksm_merging_pages;
930 /*
931 * Represent how many pages are checked for ksm merging
932 * including merged and not merged.
933 */
934 unsigned long ksm_rmap_items;
935 /*
936 * Represent how many empty pages are merged with kernel zero
937 * pages when enabling KSM use_zero_pages.
938 */
939 atomic_long_t ksm_zero_pages;
940 #endif /* CONFIG_KSM */
941 #ifdef CONFIG_LRU_GEN
942 struct {
943 /* this mm_struct is on lru_gen_mm_list */
944 struct list_head list;
945 /*
946 * Set when switching to this mm_struct, as a hint of
947 * whether it has been used since the last time per-node
948 * page table walkers cleared the corresponding bits.
949 */
950 unsigned long bitmap;
951 #ifdef CONFIG_MEMCG
952 /* points to the memcg of "owner" above */
953 struct mem_cgroup *memcg;
954 #endif
955 } lru_gen;
956 #endif /* CONFIG_LRU_GEN */
957
958 ANDROID_KABI_RESERVE(1);
959 ANDROID_BACKPORT_RESERVE(1);
960 } __randomize_layout;
961
962 /*
963 * The mm_cpumask needs to be at the end of mm_struct, because it
964 * is dynamically sized based on nr_cpu_ids.
965 */
966 unsigned long cpu_bitmap[];
967 };
968
969 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
970 MT_FLAGS_USE_RCU)
971 extern struct mm_struct init_mm;
972
973 /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)974 static inline void mm_init_cpumask(struct mm_struct *mm)
975 {
976 unsigned long cpu_bitmap = (unsigned long)mm;
977
978 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
979 cpumask_clear((struct cpumask *)cpu_bitmap);
980 }
981
982 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)983 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
984 {
985 return (struct cpumask *)&mm->cpu_bitmap;
986 }
987
988 #ifdef CONFIG_LRU_GEN
989
990 struct lru_gen_mm_list {
991 /* mm_struct list for page table walkers */
992 struct list_head fifo;
993 /* protects the list above */
994 spinlock_t lock;
995 };
996
997 void lru_gen_add_mm(struct mm_struct *mm);
998 void lru_gen_del_mm(struct mm_struct *mm);
999 #ifdef CONFIG_MEMCG
1000 void lru_gen_migrate_mm(struct mm_struct *mm);
1001 #endif
1002
lru_gen_init_mm(struct mm_struct * mm)1003 static inline void lru_gen_init_mm(struct mm_struct *mm)
1004 {
1005 INIT_LIST_HEAD(&mm->lru_gen.list);
1006 mm->lru_gen.bitmap = 0;
1007 #ifdef CONFIG_MEMCG
1008 mm->lru_gen.memcg = NULL;
1009 #endif
1010 }
1011
lru_gen_use_mm(struct mm_struct * mm)1012 static inline void lru_gen_use_mm(struct mm_struct *mm)
1013 {
1014 /*
1015 * When the bitmap is set, page reclaim knows this mm_struct has been
1016 * used since the last time it cleared the bitmap. So it might be worth
1017 * walking the page tables of this mm_struct to clear the accessed bit.
1018 */
1019 WRITE_ONCE(mm->lru_gen.bitmap, -1);
1020 }
1021
1022 #else /* !CONFIG_LRU_GEN */
1023
lru_gen_add_mm(struct mm_struct * mm)1024 static inline void lru_gen_add_mm(struct mm_struct *mm)
1025 {
1026 }
1027
lru_gen_del_mm(struct mm_struct * mm)1028 static inline void lru_gen_del_mm(struct mm_struct *mm)
1029 {
1030 }
1031
1032 #ifdef CONFIG_MEMCG
lru_gen_migrate_mm(struct mm_struct * mm)1033 static inline void lru_gen_migrate_mm(struct mm_struct *mm)
1034 {
1035 }
1036 #endif
1037
lru_gen_init_mm(struct mm_struct * mm)1038 static inline void lru_gen_init_mm(struct mm_struct *mm)
1039 {
1040 }
1041
lru_gen_use_mm(struct mm_struct * mm)1042 static inline void lru_gen_use_mm(struct mm_struct *mm)
1043 {
1044 }
1045
1046 #endif /* CONFIG_LRU_GEN */
1047
1048 struct vma_iterator {
1049 struct ma_state mas;
1050 };
1051
1052 #define VMA_ITERATOR(name, __mm, __addr) \
1053 struct vma_iterator name = { \
1054 .mas = { \
1055 .tree = &(__mm)->mm_mt, \
1056 .index = __addr, \
1057 .node = MAS_START, \
1058 }, \
1059 }
1060
vma_iter_init(struct vma_iterator * vmi,struct mm_struct * mm,unsigned long addr)1061 static inline void vma_iter_init(struct vma_iterator *vmi,
1062 struct mm_struct *mm, unsigned long addr)
1063 {
1064 mas_init(&vmi->mas, &mm->mm_mt, addr);
1065 }
1066
1067 #ifdef CONFIG_SCHED_MM_CID
1068
1069 enum mm_cid_state {
1070 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */
1071 MM_CID_LAZY_PUT = (1U << 31),
1072 };
1073
mm_cid_is_unset(int cid)1074 static inline bool mm_cid_is_unset(int cid)
1075 {
1076 return cid == MM_CID_UNSET;
1077 }
1078
mm_cid_is_lazy_put(int cid)1079 static inline bool mm_cid_is_lazy_put(int cid)
1080 {
1081 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT);
1082 }
1083
mm_cid_is_valid(int cid)1084 static inline bool mm_cid_is_valid(int cid)
1085 {
1086 return !(cid & MM_CID_LAZY_PUT);
1087 }
1088
mm_cid_set_lazy_put(int cid)1089 static inline int mm_cid_set_lazy_put(int cid)
1090 {
1091 return cid | MM_CID_LAZY_PUT;
1092 }
1093
mm_cid_clear_lazy_put(int cid)1094 static inline int mm_cid_clear_lazy_put(int cid)
1095 {
1096 return cid & ~MM_CID_LAZY_PUT;
1097 }
1098
1099 /* Accessor for struct mm_struct's cidmask. */
mm_cidmask(struct mm_struct * mm)1100 static inline cpumask_t *mm_cidmask(struct mm_struct *mm)
1101 {
1102 unsigned long cid_bitmap = (unsigned long)mm;
1103
1104 cid_bitmap += offsetof(struct mm_struct, cpu_bitmap);
1105 /* Skip cpu_bitmap */
1106 cid_bitmap += cpumask_size();
1107 return (struct cpumask *)cid_bitmap;
1108 }
1109
mm_init_cid(struct mm_struct * mm)1110 static inline void mm_init_cid(struct mm_struct *mm)
1111 {
1112 int i;
1113
1114 for_each_possible_cpu(i) {
1115 struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i);
1116
1117 pcpu_cid->cid = MM_CID_UNSET;
1118 pcpu_cid->time = 0;
1119 }
1120 cpumask_clear(mm_cidmask(mm));
1121 }
1122
mm_alloc_cid(struct mm_struct * mm)1123 static inline int mm_alloc_cid(struct mm_struct *mm)
1124 {
1125 mm->pcpu_cid = alloc_percpu(struct mm_cid);
1126 if (!mm->pcpu_cid)
1127 return -ENOMEM;
1128 mm_init_cid(mm);
1129 return 0;
1130 }
1131
mm_destroy_cid(struct mm_struct * mm)1132 static inline void mm_destroy_cid(struct mm_struct *mm)
1133 {
1134 free_percpu(mm->pcpu_cid);
1135 mm->pcpu_cid = NULL;
1136 }
1137
mm_cid_size(void)1138 static inline unsigned int mm_cid_size(void)
1139 {
1140 return cpumask_size();
1141 }
1142 #else /* CONFIG_SCHED_MM_CID */
mm_init_cid(struct mm_struct * mm)1143 static inline void mm_init_cid(struct mm_struct *mm) { }
mm_alloc_cid(struct mm_struct * mm)1144 static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; }
mm_destroy_cid(struct mm_struct * mm)1145 static inline void mm_destroy_cid(struct mm_struct *mm) { }
mm_cid_size(void)1146 static inline unsigned int mm_cid_size(void)
1147 {
1148 return 0;
1149 }
1150 #endif /* CONFIG_SCHED_MM_CID */
1151
1152 struct mmu_gather;
1153 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
1154 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
1155 extern void tlb_finish_mmu(struct mmu_gather *tlb);
1156
1157 struct vm_fault;
1158
1159 /**
1160 * typedef vm_fault_t - Return type for page fault handlers.
1161 *
1162 * Page fault handlers return a bitmask of %VM_FAULT values.
1163 */
1164 typedef __bitwise unsigned int vm_fault_t;
1165
1166 /**
1167 * enum vm_fault_reason - Page fault handlers return a bitmask of
1168 * these values to tell the core VM what happened when handling the
1169 * fault. Used to decide whether a process gets delivered SIGBUS or
1170 * just gets major/minor fault counters bumped up.
1171 *
1172 * @VM_FAULT_OOM: Out Of Memory
1173 * @VM_FAULT_SIGBUS: Bad access
1174 * @VM_FAULT_MAJOR: Page read from storage
1175 * @VM_FAULT_HWPOISON: Hit poisoned small page
1176 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
1177 * in upper bits
1178 * @VM_FAULT_SIGSEGV: segmentation fault
1179 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
1180 * @VM_FAULT_LOCKED: ->fault locked the returned page
1181 * @VM_FAULT_RETRY: ->fault blocked, must retry
1182 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
1183 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
1184 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
1185 * fsync() to complete (for synchronous page faults
1186 * in DAX)
1187 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released
1188 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
1189 *
1190 */
1191 enum vm_fault_reason {
1192 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
1193 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
1194 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
1195 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
1196 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
1197 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
1198 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
1199 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
1200 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
1201 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
1202 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
1203 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
1204 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000,
1205 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
1206 };
1207
1208 /* Encode hstate index for a hwpoisoned large page */
1209 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
1210 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
1211
1212 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
1213 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
1214 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
1215
1216 #define VM_FAULT_RESULT_TRACE \
1217 { VM_FAULT_OOM, "OOM" }, \
1218 { VM_FAULT_SIGBUS, "SIGBUS" }, \
1219 { VM_FAULT_MAJOR, "MAJOR" }, \
1220 { VM_FAULT_HWPOISON, "HWPOISON" }, \
1221 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
1222 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
1223 { VM_FAULT_NOPAGE, "NOPAGE" }, \
1224 { VM_FAULT_LOCKED, "LOCKED" }, \
1225 { VM_FAULT_RETRY, "RETRY" }, \
1226 { VM_FAULT_FALLBACK, "FALLBACK" }, \
1227 { VM_FAULT_DONE_COW, "DONE_COW" }, \
1228 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \
1229 { VM_FAULT_COMPLETED, "COMPLETED" }
1230
1231 struct vm_special_mapping {
1232 const char *name; /* The name, e.g. "[vdso]". */
1233
1234 /*
1235 * If .fault is not provided, this points to a
1236 * NULL-terminated array of pages that back the special mapping.
1237 *
1238 * This must not be NULL unless .fault is provided.
1239 */
1240 struct page **pages;
1241
1242 /*
1243 * If non-NULL, then this is called to resolve page faults
1244 * on the special mapping. If used, .pages is not checked.
1245 */
1246 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
1247 struct vm_area_struct *vma,
1248 struct vm_fault *vmf);
1249
1250 int (*mremap)(const struct vm_special_mapping *sm,
1251 struct vm_area_struct *new_vma);
1252 };
1253
1254 enum tlb_flush_reason {
1255 TLB_FLUSH_ON_TASK_SWITCH,
1256 TLB_REMOTE_SHOOTDOWN,
1257 TLB_LOCAL_SHOOTDOWN,
1258 TLB_LOCAL_MM_SHOOTDOWN,
1259 TLB_REMOTE_SEND_IPI,
1260 NR_TLB_FLUSH_REASONS,
1261 };
1262
1263 /**
1264 * enum fault_flag - Fault flag definitions.
1265 * @FAULT_FLAG_WRITE: Fault was a write fault.
1266 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
1267 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
1268 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
1269 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
1270 * @FAULT_FLAG_TRIED: The fault has been tried once.
1271 * @FAULT_FLAG_USER: The fault originated in userspace.
1272 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
1273 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
1274 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
1275 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a
1276 * COW mapping, making sure that an exclusive anon page is
1277 * mapped after the fault.
1278 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
1279 * We should only access orig_pte if this flag set.
1280 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock.
1281 *
1282 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
1283 * whether we would allow page faults to retry by specifying these two
1284 * fault flags correctly. Currently there can be three legal combinations:
1285 *
1286 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
1287 * this is the first try
1288 *
1289 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
1290 * we've already tried at least once
1291 *
1292 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
1293 *
1294 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
1295 * be used. Note that page faults can be allowed to retry for multiple times,
1296 * in which case we'll have an initial fault with flags (a) then later on
1297 * continuous faults with flags (b). We should always try to detect pending
1298 * signals before a retry to make sure the continuous page faults can still be
1299 * interrupted if necessary.
1300 *
1301 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
1302 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
1303 * applied to mappings that are not COW mappings.
1304 */
1305 enum fault_flag {
1306 FAULT_FLAG_WRITE = 1 << 0,
1307 FAULT_FLAG_MKWRITE = 1 << 1,
1308 FAULT_FLAG_ALLOW_RETRY = 1 << 2,
1309 FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
1310 FAULT_FLAG_KILLABLE = 1 << 4,
1311 FAULT_FLAG_TRIED = 1 << 5,
1312 FAULT_FLAG_USER = 1 << 6,
1313 FAULT_FLAG_REMOTE = 1 << 7,
1314 FAULT_FLAG_INSTRUCTION = 1 << 8,
1315 FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
1316 FAULT_FLAG_UNSHARE = 1 << 10,
1317 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11,
1318 FAULT_FLAG_VMA_LOCK = 1 << 12,
1319 };
1320
1321 typedef unsigned int __bitwise zap_flags_t;
1322
1323 /* Flags for clear_young_dirty_ptes(). */
1324 typedef int __bitwise cydp_t;
1325
1326 /* Clear the access bit */
1327 #define CYDP_CLEAR_YOUNG ((__force cydp_t)BIT(0))
1328
1329 /* Clear the dirty bit */
1330 #define CYDP_CLEAR_DIRTY ((__force cydp_t)BIT(1))
1331
1332 /*
1333 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
1334 * other. Here is what they mean, and how to use them:
1335 *
1336 *
1337 * FIXME: For pages which are part of a filesystem, mappings are subject to the
1338 * lifetime enforced by the filesystem and we need guarantees that longterm
1339 * users like RDMA and V4L2 only establish mappings which coordinate usage with
1340 * the filesystem. Ideas for this coordination include revoking the longterm
1341 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was
1342 * added after the problem with filesystems was found FS DAX VMAs are
1343 * specifically failed. Filesystem pages are still subject to bugs and use of
1344 * FOLL_LONGTERM should be avoided on those pages.
1345 *
1346 * In the CMA case: long term pins in a CMA region would unnecessarily fragment
1347 * that region. And so, CMA attempts to migrate the page before pinning, when
1348 * FOLL_LONGTERM is specified.
1349 *
1350 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
1351 * but an additional pin counting system) will be invoked. This is intended for
1352 * anything that gets a page reference and then touches page data (for example,
1353 * Direct IO). This lets the filesystem know that some non-file-system entity is
1354 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages
1355 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by
1356 * a call to unpin_user_page().
1357 *
1358 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
1359 * and separate refcounting mechanisms, however, and that means that each has
1360 * its own acquire and release mechanisms:
1361 *
1362 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
1363 *
1364 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
1365 *
1366 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
1367 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
1368 * calls applied to them, and that's perfectly OK. This is a constraint on the
1369 * callers, not on the pages.)
1370 *
1371 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
1372 * directly by the caller. That's in order to help avoid mismatches when
1373 * releasing pages: get_user_pages*() pages must be released via put_page(),
1374 * while pin_user_pages*() pages must be released via unpin_user_page().
1375 *
1376 * Please see Documentation/core-api/pin_user_pages.rst for more information.
1377 */
1378
1379 enum {
1380 /* check pte is writable */
1381 FOLL_WRITE = 1 << 0,
1382 /* do get_page on page */
1383 FOLL_GET = 1 << 1,
1384 /* give error on hole if it would be zero */
1385 FOLL_DUMP = 1 << 2,
1386 /* get_user_pages read/write w/o permission */
1387 FOLL_FORCE = 1 << 3,
1388 /*
1389 * if a disk transfer is needed, start the IO and return without waiting
1390 * upon it
1391 */
1392 FOLL_NOWAIT = 1 << 4,
1393 /* do not fault in pages */
1394 FOLL_NOFAULT = 1 << 5,
1395 /* check page is hwpoisoned */
1396 FOLL_HWPOISON = 1 << 6,
1397 /* don't do file mappings */
1398 FOLL_ANON = 1 << 7,
1399 /*
1400 * FOLL_LONGTERM indicates that the page will be held for an indefinite
1401 * time period _often_ under userspace control. This is in contrast to
1402 * iov_iter_get_pages(), whose usages are transient.
1403 */
1404 FOLL_LONGTERM = 1 << 8,
1405 /* split huge pmd before returning */
1406 FOLL_SPLIT_PMD = 1 << 9,
1407 /* allow returning PCI P2PDMA pages */
1408 FOLL_PCI_P2PDMA = 1 << 10,
1409 /* allow interrupts from generic signals */
1410 FOLL_INTERRUPTIBLE = 1 << 11,
1411 /*
1412 * Always honor (trigger) NUMA hinting faults.
1413 *
1414 * FOLL_WRITE implicitly honors NUMA hinting faults because a
1415 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE
1416 * apply). get_user_pages_fast_only() always implicitly honors NUMA
1417 * hinting faults.
1418 */
1419 FOLL_HONOR_NUMA_FAULT = 1 << 12,
1420
1421 /* See also internal only FOLL flags in mm/internal.h */
1422 };
1423
1424 #endif /* _LINUX_MM_TYPES_H */
1425