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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/types.h>
23#include <linux/rseq_types.h>
24#include <linux/bitmap.h>
25
26#include <asm/mmu.h>
27
28#ifndef AT_VECTOR_SIZE_ARCH
29#define AT_VECTOR_SIZE_ARCH 0
30#endif
31#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
32
33
34struct address_space;
35struct futex_private_hash;
36struct mem_cgroup;
37
38typedef struct {
39 unsigned long f;
40} memdesc_flags_t;
41
42/*
43 * Each physical page in the system has a struct page associated with
44 * it to keep track of whatever it is we are using the page for at the
45 * moment. Note that we have no way to track which tasks are using
46 * a page, though if it is a pagecache page, rmap structures can tell us
47 * who is mapping it.
48 *
49 * If you allocate the page using alloc_pages(), you can use some of the
50 * space in struct page for your own purposes. The five words in the main
51 * union are available, except for bit 0 of the first word which must be
52 * kept clear. Many users use this word to store a pointer to an object
53 * which is guaranteed to be aligned. If you use the same storage as
54 * page->mapping, you must restore it to NULL before freeing the page.
55 *
56 * The mapcount field must not be used for own purposes.
57 *
58 * If you want to use the refcount field, it must be used in such a way
59 * that other CPUs temporarily incrementing and then decrementing the
60 * refcount does not cause problems. On receiving the page from
61 * alloc_pages(), the refcount will be positive.
62 *
63 * If you allocate pages of order > 0, you can use some of the fields
64 * in each subpage, but you may need to restore some of their values
65 * afterwards.
66 *
67 * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
68 * That requires that freelist & counters in struct slab be adjacent and
69 * double-word aligned. Because struct slab currently just reinterprets the
70 * bits of struct page, we align all struct pages to double-word boundaries,
71 * and ensure that 'freelist' is aligned within struct slab.
72 */
73#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
74#define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
75#else
76#define _struct_page_alignment __aligned(sizeof(unsigned long))
77#endif
78
79struct page {
80 memdesc_flags_t flags; /* Atomic flags, some possibly
81 * updated asynchronously */
82 /*
83 * Five words (20/40 bytes) are available in this union.
84 * WARNING: bit 0 of the first word is used for PageTail(). That
85 * means the other users of this union MUST NOT use the bit to
86 * avoid collision and false-positive PageTail().
87 */
88 union {
89 struct { /* Page cache and anonymous pages */
90 /**
91 * @lru: Pageout list, eg. active_list protected by
92 * lruvec->lru_lock. Sometimes used as a generic list
93 * by the page owner.
94 */
95 union {
96 struct list_head lru;
97
98 /* Or, free page */
99 struct list_head buddy_list;
100 struct list_head pcp_list;
101 struct llist_node pcp_llist;
102 };
103 struct address_space *mapping;
104 union {
105 pgoff_t __folio_index; /* Our offset within mapping. */
106 unsigned long share; /* share count for fsdax */
107 };
108 /**
109 * @private: Mapping-private opaque data.
110 * Usually used for buffer_heads if PagePrivate.
111 * Used for swp_entry_t if swapcache flag set.
112 * Indicates order in the buddy system if PageBuddy
113 * or on pcp_llist.
114 */
115 unsigned long private;
116 };
117 struct { /* page_pool used by netstack */
118 /**
119 * @pp_magic: magic value to avoid recycling non
120 * page_pool allocated pages.
121 */
122 unsigned long pp_magic;
123 struct page_pool *pp;
124 unsigned long _pp_mapping_pad;
125 unsigned long dma_addr;
126 atomic_long_t pp_ref_count;
127 };
128 struct { /* Tail pages of compound page */
129 unsigned long compound_head; /* Bit zero is set */
130 };
131 struct { /* ZONE_DEVICE pages */
132 /*
133 * The first word is used for compound_head or folio
134 * pgmap
135 */
136 void *_unused_pgmap_compound_head;
137 void *zone_device_data;
138 /*
139 * ZONE_DEVICE private pages are counted as being
140 * mapped so the next 3 words hold the mapping, index,
141 * and private fields from the source anonymous or
142 * page cache page while the page is migrated to device
143 * private memory.
144 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
145 * use the mapping, index, and private fields when
146 * pmem backed DAX files are mapped.
147 */
148 };
149
150 /** @rcu_head: You can use this to free a page by RCU. */
151 struct rcu_head rcu_head;
152 };
153
154 union { /* This union is 4 bytes in size. */
155 /*
156 * For head pages of typed folios, the value stored here
157 * allows for determining what this page is used for. The
158 * tail pages of typed folios will not store a type
159 * (page_type == _mapcount == -1).
160 *
161 * See page-flags.h for a list of page types which are currently
162 * stored here.
163 *
164 * Owners of typed folios may reuse the lower 16 bit of the
165 * head page page_type field after setting the page type,
166 * but must reset these 16 bit to -1 before clearing the
167 * page type.
168 */
169 unsigned int page_type;
170
171 /*
172 * For pages that are part of non-typed folios for which mappings
173 * are tracked via the RMAP, encodes the number of times this page
174 * is directly referenced by a page table.
175 *
176 * Note that the mapcount is always initialized to -1, so that
177 * transitions both from it and to it can be tracked, using
178 * atomic_inc_and_test() and atomic_add_negative(-1).
179 */
180 atomic_t _mapcount;
181 };
182
183 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
184 atomic_t _refcount;
185
186#ifdef CONFIG_MEMCG
187 unsigned long memcg_data;
188#elif defined(CONFIG_SLAB_OBJ_EXT)
189 unsigned long _unused_slab_obj_exts;
190#endif
191
192 /*
193 * On machines where all RAM is mapped into kernel address space,
194 * we can simply calculate the virtual address. On machines with
195 * highmem some memory is mapped into kernel virtual memory
196 * dynamically, so we need a place to store that address.
197 * Note that this field could be 16 bits on x86 ... ;)
198 *
199 * Architectures with slow multiplication can define
200 * WANT_PAGE_VIRTUAL in asm/page.h
201 */
202#if defined(WANT_PAGE_VIRTUAL)
203 void *virtual; /* Kernel virtual address (NULL if
204 not kmapped, ie. highmem) */
205#endif /* WANT_PAGE_VIRTUAL */
206
207#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
208 int _last_cpupid;
209#endif
210
211#ifdef CONFIG_KMSAN
212 /*
213 * KMSAN metadata for this page:
214 * - shadow page: every bit indicates whether the corresponding
215 * bit of the original page is initialized (0) or not (1);
216 * - origin page: every 4 bytes contain an id of the stack trace
217 * where the uninitialized value was created.
218 */
219 struct page *kmsan_shadow;
220 struct page *kmsan_origin;
221#endif
222} _struct_page_alignment;
223
224/*
225 * struct encoded_page - a nonexistent type marking this pointer
226 *
227 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but
228 * with the low bits of the pointer indicating extra context-dependent
229 * information. Only used in mmu_gather handling, and this acts as a type
230 * system check on that use.
231 *
232 * We only really have two guaranteed bits in general, although you could
233 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
234 * for more.
235 *
236 * Use the supplied helper functions to endcode/decode the pointer and bits.
237 */
238struct encoded_page;
239
240#define ENCODED_PAGE_BITS 3ul
241
242/* Perform rmap removal after we have flushed the TLB. */
243#define ENCODED_PAGE_BIT_DELAY_RMAP 1ul
244
245/*
246 * The next item in an encoded_page array is the "nr_pages" argument, specifying
247 * the number of consecutive pages starting from this page, that all belong to
248 * the same folio. For example, "nr_pages" corresponds to the number of folio
249 * references that must be dropped. If this bit is not set, "nr_pages" is
250 * implicitly 1.
251 */
252#define ENCODED_PAGE_BIT_NR_PAGES_NEXT 2ul
253
254static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
255{
256 BUILD_BUG_ON(flags > ENCODED_PAGE_BITS);
257 return (struct encoded_page *)(flags | (unsigned long)page);
258}
259
260static inline unsigned long encoded_page_flags(struct encoded_page *page)
261{
262 return ENCODED_PAGE_BITS & (unsigned long)page;
263}
264
265static inline struct page *encoded_page_ptr(struct encoded_page *page)
266{
267 return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page);
268}
269
270static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr)
271{
272 VM_WARN_ON_ONCE((nr << 2) >> 2 != nr);
273 return (struct encoded_page *)(nr << 2);
274}
275
276static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page)
277{
278 return ((unsigned long)page) >> 2;
279}
280
281/*
282 * A swap entry has to fit into a "unsigned long", as the entry is hidden
283 * in the "index" field of the swapper address space.
284 */
285typedef struct {
286 unsigned long val;
287} swp_entry_t;
288
289/**
290 * typedef softleaf_t - Describes a page table software leaf entry, abstracted
291 * from its architecture-specific encoding.
292 *
293 * Page table leaf entries are those which do not reference any descendent page
294 * tables but rather either reference a data page, are an empty (or 'none'
295 * entry), or contain a non-present entry.
296 *
297 * If referencing another page table or a data page then the page table entry is
298 * pertinent to hardware - that is it tells the hardware how to decode the page
299 * table entry.
300 *
301 * Otherwise it is a software-defined leaf page table entry, which this type
302 * describes. See leafops.h and specifically @softleaf_type for a list of all
303 * possible kinds of software leaf entry.
304 *
305 * A softleaf_t entry is abstracted from the hardware page table entry, so is
306 * not architecture-specific.
307 *
308 * NOTE: While we transition from the confusing swp_entry_t type used for this
309 * purpose, we simply alias this type. This will be removed once the
310 * transition is complete.
311 */
312typedef swp_entry_t softleaf_t;
313
314#if defined(CONFIG_MEMCG) || defined(CONFIG_SLAB_OBJ_EXT)
315/* We have some extra room after the refcount in tail pages. */
316#define NR_PAGES_IN_LARGE_FOLIO
317#endif
318
319/*
320 * On 32bit, we can cut the required metadata in half, because:
321 * (a) PID_MAX_LIMIT implicitly limits the number of MMs we could ever have,
322 * so we can limit MM IDs to 15 bit (32767).
323 * (b) We don't expect folios where even a single complete PTE mapping by
324 * one MM would exceed 15 bits (order-15).
325 */
326#ifdef CONFIG_64BIT
327typedef int mm_id_mapcount_t;
328#define MM_ID_MAPCOUNT_MAX INT_MAX
329typedef unsigned int mm_id_t;
330#else /* !CONFIG_64BIT */
331typedef short mm_id_mapcount_t;
332#define MM_ID_MAPCOUNT_MAX SHRT_MAX
333typedef unsigned short mm_id_t;
334#endif /* CONFIG_64BIT */
335
336/* We implicitly use the dummy ID for init-mm etc. where we never rmap pages. */
337#define MM_ID_DUMMY 0
338#define MM_ID_MIN (MM_ID_DUMMY + 1)
339
340/*
341 * We leave the highest bit of each MM id unused, so we can store a flag
342 * in the highest bit of each folio->_mm_id[].
343 */
344#define MM_ID_BITS ((sizeof(mm_id_t) * BITS_PER_BYTE) - 1)
345#define MM_ID_MASK ((1U << MM_ID_BITS) - 1)
346#define MM_ID_MAX MM_ID_MASK
347
348/*
349 * In order to use bit_spin_lock(), which requires an unsigned long, we
350 * operate on folio->_mm_ids when working on flags.
351 */
352#define FOLIO_MM_IDS_LOCK_BITNUM MM_ID_BITS
353#define FOLIO_MM_IDS_LOCK_BIT BIT(FOLIO_MM_IDS_LOCK_BITNUM)
354#define FOLIO_MM_IDS_SHARED_BITNUM (2 * MM_ID_BITS + 1)
355#define FOLIO_MM_IDS_SHARED_BIT BIT(FOLIO_MM_IDS_SHARED_BITNUM)
356
357/**
358 * struct folio - Represents a contiguous set of bytes.
359 * @flags: Identical to the page flags.
360 * @lru: Least Recently Used list; tracks how recently this folio was used.
361 * @mlock_count: Number of times this folio has been pinned by mlock().
362 * @mapping: The file this page belongs to, or refers to the anon_vma for
363 * anonymous memory.
364 * @index: Offset within the file, in units of pages. For anonymous memory,
365 * this is the index from the beginning of the mmap.
366 * @share: number of DAX mappings that reference this folio. See
367 * dax_associate_entry.
368 * @private: Filesystem per-folio data (see folio_attach_private()).
369 * @swap: Used for swp_entry_t if folio_test_swapcache().
370 * @_mapcount: Do not access this member directly. Use folio_mapcount() to
371 * find out how many times this folio is mapped by userspace.
372 * @_refcount: Do not access this member directly. Use folio_ref_count()
373 * to find how many references there are to this folio.
374 * @memcg_data: Memory Control Group data.
375 * @pgmap: Metadata for ZONE_DEVICE mappings
376 * @virtual: Virtual address in the kernel direct map.
377 * @_last_cpupid: IDs of last CPU and last process that accessed the folio.
378 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
379 * @_large_mapcount: Do not use directly, call folio_mapcount().
380 * @_nr_pages_mapped: Do not use outside of rmap and debug code.
381 * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
382 * @_nr_pages: Do not use directly, call folio_nr_pages().
383 * @_mm_id: Do not use outside of rmap code.
384 * @_mm_ids: Do not use outside of rmap code.
385 * @_mm_id_mapcount: Do not use outside of rmap code.
386 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
387 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
388 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
389 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
390 * @_deferred_list: Folios to be split under memory pressure.
391 * @_unused_slab_obj_exts: Placeholder to match obj_exts in struct slab.
392 *
393 * A folio is a physically, virtually and logically contiguous set
394 * of bytes. It is a power-of-two in size, and it is aligned to that
395 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is
396 * in the page cache, it is at a file offset which is a multiple of that
397 * power-of-two. It may be mapped into userspace at an address which is
398 * at an arbitrary page offset, but its kernel virtual address is aligned
399 * to its size.
400 */
401struct folio {
402 /* private: don't document the anon union */
403 union {
404 struct {
405 /* public: */
406 memdesc_flags_t flags;
407 union {
408 struct list_head lru;
409 /* private: avoid cluttering the output */
410 /* For the Unevictable "LRU list" slot */
411 struct {
412 /* Avoid compound_head */
413 void *__filler;
414 /* public: */
415 unsigned int mlock_count;
416 /* private: */
417 };
418 /* public: */
419 struct dev_pagemap *pgmap;
420 };
421 struct address_space *mapping;
422 union {
423 pgoff_t index;
424 unsigned long share;
425 };
426 union {
427 void *private;
428 swp_entry_t swap;
429 };
430 atomic_t _mapcount;
431 atomic_t _refcount;
432#ifdef CONFIG_MEMCG
433 unsigned long memcg_data;
434#elif defined(CONFIG_SLAB_OBJ_EXT)
435 unsigned long _unused_slab_obj_exts;
436#endif
437#if defined(WANT_PAGE_VIRTUAL)
438 void *virtual;
439#endif
440#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
441 int _last_cpupid;
442#endif
443 /* private: the union with struct page is transitional */
444 };
445 struct page page;
446 };
447 union {
448 struct {
449 unsigned long _flags_1;
450 unsigned long _head_1;
451 union {
452 struct {
453 /* public: */
454 atomic_t _large_mapcount;
455 atomic_t _nr_pages_mapped;
456#ifdef CONFIG_64BIT
457 atomic_t _entire_mapcount;
458 atomic_t _pincount;
459#endif /* CONFIG_64BIT */
460 mm_id_mapcount_t _mm_id_mapcount[2];
461 union {
462 mm_id_t _mm_id[2];
463 unsigned long _mm_ids;
464 };
465 /* private: the union with struct page is transitional */
466 };
467 unsigned long _usable_1[4];
468 };
469 atomic_t _mapcount_1;
470 atomic_t _refcount_1;
471 /* public: */
472#ifdef NR_PAGES_IN_LARGE_FOLIO
473 unsigned int _nr_pages;
474#endif /* NR_PAGES_IN_LARGE_FOLIO */
475 /* private: the union with struct page is transitional */
476 };
477 struct page __page_1;
478 };
479 union {
480 struct {
481 unsigned long _flags_2;
482 unsigned long _head_2;
483 /* public: */
484 struct list_head _deferred_list;
485#ifndef CONFIG_64BIT
486 atomic_t _entire_mapcount;
487 atomic_t _pincount;
488#endif /* !CONFIG_64BIT */
489 /* private: the union with struct page is transitional */
490 };
491 struct page __page_2;
492 };
493 union {
494 struct {
495 unsigned long _flags_3;
496 unsigned long _head_3;
497 /* public: */
498 void *_hugetlb_subpool;
499 void *_hugetlb_cgroup;
500 void *_hugetlb_cgroup_rsvd;
501 void *_hugetlb_hwpoison;
502 /* private: the union with struct page is transitional */
503 };
504 struct page __page_3;
505 };
506};
507
508#define FOLIO_MATCH(pg, fl) \
509 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
510FOLIO_MATCH(flags, flags);
511FOLIO_MATCH(lru, lru);
512FOLIO_MATCH(mapping, mapping);
513FOLIO_MATCH(compound_head, lru);
514FOLIO_MATCH(__folio_index, index);
515FOLIO_MATCH(private, private);
516FOLIO_MATCH(_mapcount, _mapcount);
517FOLIO_MATCH(_refcount, _refcount);
518#ifdef CONFIG_MEMCG
519FOLIO_MATCH(memcg_data, memcg_data);
520#endif
521#if defined(WANT_PAGE_VIRTUAL)
522FOLIO_MATCH(virtual, virtual);
523#endif
524#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
525FOLIO_MATCH(_last_cpupid, _last_cpupid);
526#endif
527#undef FOLIO_MATCH
528#define FOLIO_MATCH(pg, fl) \
529 static_assert(offsetof(struct folio, fl) == \
530 offsetof(struct page, pg) + sizeof(struct page))
531FOLIO_MATCH(flags, _flags_1);
532FOLIO_MATCH(compound_head, _head_1);
533FOLIO_MATCH(_mapcount, _mapcount_1);
534FOLIO_MATCH(_refcount, _refcount_1);
535#undef FOLIO_MATCH
536#define FOLIO_MATCH(pg, fl) \
537 static_assert(offsetof(struct folio, fl) == \
538 offsetof(struct page, pg) + 2 * sizeof(struct page))
539FOLIO_MATCH(flags, _flags_2);
540FOLIO_MATCH(compound_head, _head_2);
541#undef FOLIO_MATCH
542#define FOLIO_MATCH(pg, fl) \
543 static_assert(offsetof(struct folio, fl) == \
544 offsetof(struct page, pg) + 3 * sizeof(struct page))
545FOLIO_MATCH(flags, _flags_3);
546FOLIO_MATCH(compound_head, _head_3);
547#undef FOLIO_MATCH
548
549/**
550 * struct ptdesc - Memory descriptor for page tables.
551 * @pt_flags: enum pt_flags plus zone/node/section.
552 * @pt_rcu_head: For freeing page table pages.
553 * @pt_list: List of used page tables. Used for s390 gmap shadow pages
554 * (which are not linked into the user page tables) and x86
555 * pgds.
556 * @_pt_pad_1: Padding that aliases with page's compound head.
557 * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs.
558 * @__page_mapping: Aliases with page->mapping. Unused for page tables.
559 * @pt_index: Used for s390 gmap.
560 * @pt_mm: Used for x86 pgds.
561 * @pt_frag_refcount: For fragmented page table tracking. Powerpc only.
562 * @pt_share_count: Used for HugeTLB PMD page table share count.
563 * @_pt_pad_2: Padding to ensure proper alignment.
564 * @ptl: Lock for the page table.
565 * @__page_type: Same as page->page_type. Unused for page tables.
566 * @__page_refcount: Same as page refcount.
567 * @pt_memcg_data: Memcg data. Tracked for page tables here.
568 *
569 * This struct overlays struct page for now. Do not modify without a good
570 * understanding of the issues.
571 */
572struct ptdesc {
573 memdesc_flags_t pt_flags;
574
575 union {
576 struct rcu_head pt_rcu_head;
577 struct list_head pt_list;
578 struct {
579 unsigned long _pt_pad_1;
580 pgtable_t pmd_huge_pte;
581 };
582 };
583 unsigned long __page_mapping;
584
585 union {
586 pgoff_t pt_index;
587 struct mm_struct *pt_mm;
588 atomic_t pt_frag_refcount;
589#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
590 atomic_t pt_share_count;
591#endif
592 };
593
594 union {
595 unsigned long _pt_pad_2;
596#if ALLOC_SPLIT_PTLOCKS
597 spinlock_t *ptl;
598#else
599 spinlock_t ptl;
600#endif
601 };
602 unsigned int __page_type;
603 atomic_t __page_refcount;
604#ifdef CONFIG_MEMCG
605 unsigned long pt_memcg_data;
606#endif
607};
608
609#define TABLE_MATCH(pg, pt) \
610 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
611TABLE_MATCH(flags, pt_flags);
612TABLE_MATCH(compound_head, pt_list);
613TABLE_MATCH(compound_head, _pt_pad_1);
614TABLE_MATCH(mapping, __page_mapping);
615TABLE_MATCH(__folio_index, pt_index);
616TABLE_MATCH(rcu_head, pt_rcu_head);
617TABLE_MATCH(page_type, __page_type);
618TABLE_MATCH(_refcount, __page_refcount);
619#ifdef CONFIG_MEMCG
620TABLE_MATCH(memcg_data, pt_memcg_data);
621#endif
622#undef TABLE_MATCH
623static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
624
625#define ptdesc_page(pt) (_Generic((pt), \
626 const struct ptdesc *: (const struct page *)(pt), \
627 struct ptdesc *: (struct page *)(pt)))
628
629#define ptdesc_folio(pt) (_Generic((pt), \
630 const struct ptdesc *: (const struct folio *)(pt), \
631 struct ptdesc *: (struct folio *)(pt)))
632
633#define page_ptdesc(p) (_Generic((p), \
634 const struct page *: (const struct ptdesc *)(p), \
635 struct page *: (struct ptdesc *)(p)))
636
637#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING
638static inline void ptdesc_pmd_pts_init(struct ptdesc *ptdesc)
639{
640 atomic_set(v: &ptdesc->pt_share_count, i: 0);
641}
642
643static inline void ptdesc_pmd_pts_inc(struct ptdesc *ptdesc)
644{
645 atomic_inc(v: &ptdesc->pt_share_count);
646}
647
648static inline void ptdesc_pmd_pts_dec(struct ptdesc *ptdesc)
649{
650 atomic_dec(v: &ptdesc->pt_share_count);
651}
652
653static inline int ptdesc_pmd_pts_count(const struct ptdesc *ptdesc)
654{
655 return atomic_read(v: &ptdesc->pt_share_count);
656}
657
658static inline bool ptdesc_pmd_is_shared(struct ptdesc *ptdesc)
659{
660 return !!ptdesc_pmd_pts_count(ptdesc);
661}
662#else
663static inline void ptdesc_pmd_pts_init(struct ptdesc *ptdesc)
664{
665}
666#endif
667
668/*
669 * Used for sizing the vmemmap region on some architectures
670 */
671#define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
672
673/*
674 * page_private can be used on tail pages. However, PagePrivate is only
675 * checked by the VM on the head page. So page_private on the tail pages
676 * should be used for data that's ancillary to the head page (eg attaching
677 * buffer heads to tail pages after attaching buffer heads to the head page)
678 */
679#define page_private(page) ((page)->private)
680
681static inline void set_page_private(struct page *page, unsigned long private)
682{
683 page->private = private;
684}
685
686static inline void *folio_get_private(const struct folio *folio)
687{
688 return folio->private;
689}
690
691typedef unsigned long vm_flags_t;
692
693/*
694 * freeptr_t represents a SLUB freelist pointer, which might be encoded
695 * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
696 */
697typedef struct { unsigned long v; } freeptr_t;
698
699/*
700 * A region containing a mapping of a non-memory backed file under NOMMU
701 * conditions. These are held in a global tree and are pinned by the VMAs that
702 * map parts of them.
703 */
704struct vm_region {
705 struct rb_node vm_rb; /* link in global region tree */
706 vm_flags_t vm_flags; /* VMA vm_flags */
707 unsigned long vm_start; /* start address of region */
708 unsigned long vm_end; /* region initialised to here */
709 unsigned long vm_top; /* region allocated to here */
710 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
711 struct file *vm_file; /* the backing file or NULL */
712
713 int vm_usage; /* region usage count (access under nommu_region_sem) */
714 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
715 * this region */
716};
717
718#ifdef CONFIG_USERFAULTFD
719#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
720struct vm_userfaultfd_ctx {
721 struct userfaultfd_ctx *ctx;
722};
723#else /* CONFIG_USERFAULTFD */
724#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
725struct vm_userfaultfd_ctx {};
726#endif /* CONFIG_USERFAULTFD */
727
728struct anon_vma_name {
729 struct kref kref;
730 /* The name needs to be at the end because it is dynamically sized. */
731 char name[];
732};
733
734#ifdef CONFIG_ANON_VMA_NAME
735/*
736 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
737 * either keep holding the lock while using the returned pointer or it should
738 * raise anon_vma_name refcount before releasing the lock.
739 */
740struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
741struct anon_vma_name *anon_vma_name_alloc(const char *name);
742void anon_vma_name_free(struct kref *kref);
743#else /* CONFIG_ANON_VMA_NAME */
744static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
745{
746 return NULL;
747}
748
749static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
750{
751 return NULL;
752}
753#endif
754
755#define VMA_LOCK_OFFSET 0x40000000
756#define VMA_REF_LIMIT (VMA_LOCK_OFFSET - 1)
757
758struct vma_numab_state {
759 /*
760 * Initialised as time in 'jiffies' after which VMA
761 * should be scanned. Delays first scan of new VMA by at
762 * least sysctl_numa_balancing_scan_delay:
763 */
764 unsigned long next_scan;
765
766 /*
767 * Time in jiffies when pids_active[] is reset to
768 * detect phase change behaviour:
769 */
770 unsigned long pids_active_reset;
771
772 /*
773 * Approximate tracking of PIDs that trapped a NUMA hinting
774 * fault. May produce false positives due to hash collisions.
775 *
776 * [0] Previous PID tracking
777 * [1] Current PID tracking
778 *
779 * Window moves after next_pid_reset has expired approximately
780 * every VMA_PID_RESET_PERIOD jiffies:
781 */
782 unsigned long pids_active[2];
783
784 /* MM scan sequence ID when scan first started after VMA creation */
785 int start_scan_seq;
786
787 /*
788 * MM scan sequence ID when the VMA was last completely scanned.
789 * A VMA is not eligible for scanning if prev_scan_seq == numa_scan_seq
790 */
791 int prev_scan_seq;
792};
793
794#ifdef __HAVE_PFNMAP_TRACKING
795struct pfnmap_track_ctx {
796 struct kref kref;
797 unsigned long pfn;
798 unsigned long size; /* in bytes */
799};
800#endif
801
802/* What action should be taken after an .mmap_prepare call is complete? */
803enum mmap_action_type {
804 MMAP_NOTHING, /* Mapping is complete, no further action. */
805 MMAP_REMAP_PFN, /* Remap PFN range. */
806 MMAP_IO_REMAP_PFN, /* I/O remap PFN range. */
807};
808
809/*
810 * Describes an action an mmap_prepare hook can instruct to be taken to complete
811 * the mapping of a VMA. Specified in vm_area_desc.
812 */
813struct mmap_action {
814 union {
815 /* Remap range. */
816 struct {
817 unsigned long start;
818 unsigned long start_pfn;
819 unsigned long size;
820 pgprot_t pgprot;
821 } remap;
822 };
823 enum mmap_action_type type;
824
825 /*
826 * If specified, this hook is invoked after the selected action has been
827 * successfully completed. Note that the VMA write lock still held.
828 *
829 * The absolute minimum ought to be done here.
830 *
831 * Returns 0 on success, or an error code.
832 */
833 int (*success_hook)(const struct vm_area_struct *vma);
834
835 /*
836 * If specified, this hook is invoked when an error occurred when
837 * attempting the selection action.
838 *
839 * The hook can return an error code in order to filter the error, but
840 * it is not valid to clear the error here.
841 */
842 int (*error_hook)(int err);
843
844 /*
845 * This should be set in rare instances where the operation required
846 * that the rmap should not be able to access the VMA until
847 * completely set up.
848 */
849 bool hide_from_rmap_until_complete :1;
850};
851
852/*
853 * Opaque type representing current VMA (vm_area_struct) flag state. Must be
854 * accessed via vma_flags_xxx() helper functions.
855 */
856#define NUM_VMA_FLAG_BITS BITS_PER_LONG
857typedef struct {
858 DECLARE_BITMAP(__vma_flags, NUM_VMA_FLAG_BITS);
859} __private vma_flags_t;
860
861/*
862 * Describes a VMA that is about to be mmap()'ed. Drivers may choose to
863 * manipulate mutable fields which will cause those fields to be updated in the
864 * resultant VMA.
865 *
866 * Helper functions are not required for manipulating any field.
867 */
868struct vm_area_desc {
869 /* Immutable state. */
870 const struct mm_struct *const mm;
871 struct file *const file; /* May vary from vm_file in stacked callers. */
872 unsigned long start;
873 unsigned long end;
874
875 /* Mutable fields. Populated with initial state. */
876 pgoff_t pgoff;
877 struct file *vm_file;
878 union {
879 vm_flags_t vm_flags;
880 vma_flags_t vma_flags;
881 };
882 pgprot_t page_prot;
883
884 /* Write-only fields. */
885 const struct vm_operations_struct *vm_ops;
886 void *private_data;
887
888 /* Take further action? */
889 struct mmap_action action;
890};
891
892/*
893 * This struct describes a virtual memory area. There is one of these
894 * per VM-area/task. A VM area is any part of the process virtual memory
895 * space that has a special rule for the page-fault handlers (ie a shared
896 * library, the executable area etc).
897 *
898 * Only explicitly marked struct members may be accessed by RCU readers before
899 * getting a stable reference.
900 *
901 * WARNING: when adding new members, please update vm_area_init_from() to copy
902 * them during vm_area_struct content duplication.
903 */
904struct vm_area_struct {
905 /* The first cache line has the info for VMA tree walking. */
906
907 union {
908 struct {
909 /* VMA covers [vm_start; vm_end) addresses within mm */
910 unsigned long vm_start;
911 unsigned long vm_end;
912 };
913 freeptr_t vm_freeptr; /* Pointer used by SLAB_TYPESAFE_BY_RCU */
914 };
915
916 /*
917 * The address space we belong to.
918 * Unstable RCU readers are allowed to read this.
919 */
920 struct mm_struct *vm_mm;
921 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
922
923 /*
924 * Flags, see mm.h.
925 * To modify use vm_flags_{init|reset|set|clear|mod} functions.
926 * Preferably, use vma_flags_xxx() functions.
927 */
928 union {
929 /* Temporary while VMA flags are being converted. */
930 const vm_flags_t vm_flags;
931 vma_flags_t flags;
932 };
933
934#ifdef CONFIG_PER_VMA_LOCK
935 /*
936 * Can only be written (using WRITE_ONCE()) while holding both:
937 * - mmap_lock (in write mode)
938 * - vm_refcnt bit at VMA_LOCK_OFFSET is set
939 * Can be read reliably while holding one of:
940 * - mmap_lock (in read or write mode)
941 * - vm_refcnt bit at VMA_LOCK_OFFSET is set or vm_refcnt > 1
942 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout
943 * while holding nothing (except RCU to keep the VMA struct allocated).
944 *
945 * This sequence counter is explicitly allowed to overflow; sequence
946 * counter reuse can only lead to occasional unnecessary use of the
947 * slowpath.
948 */
949 unsigned int vm_lock_seq;
950#endif
951 /*
952 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
953 * list, after a COW of one of the file pages. A MAP_SHARED vma
954 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
955 * or brk vma (with NULL file) can only be in an anon_vma list.
956 */
957 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
958 * page_table_lock */
959 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
960
961 /* Function pointers to deal with this struct. */
962 const struct vm_operations_struct *vm_ops;
963
964 /* Information about our backing store: */
965 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
966 units */
967 struct file * vm_file; /* File we map to (can be NULL). */
968 void * vm_private_data; /* was vm_pte (shared mem) */
969
970#ifdef CONFIG_SWAP
971 atomic_long_t swap_readahead_info;
972#endif
973#ifndef CONFIG_MMU
974 struct vm_region *vm_region; /* NOMMU mapping region */
975#endif
976#ifdef CONFIG_NUMA
977 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
978#endif
979#ifdef CONFIG_NUMA_BALANCING
980 struct vma_numab_state *numab_state; /* NUMA Balancing state */
981#endif
982#ifdef CONFIG_PER_VMA_LOCK
983 /* Unstable RCU readers are allowed to read this. */
984 refcount_t vm_refcnt ____cacheline_aligned_in_smp;
985#ifdef CONFIG_DEBUG_LOCK_ALLOC
986 struct lockdep_map vmlock_dep_map;
987#endif
988#endif
989 /*
990 * For areas with an address space and backing store,
991 * linkage into the address_space->i_mmap interval tree.
992 *
993 */
994 struct {
995 struct rb_node rb;
996 unsigned long rb_subtree_last;
997 } shared;
998#ifdef CONFIG_ANON_VMA_NAME
999 /*
1000 * For private and shared anonymous mappings, a pointer to a null
1001 * terminated string containing the name given to the vma, or NULL if
1002 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
1003 */
1004 struct anon_vma_name *anon_name;
1005#endif
1006 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
1007#ifdef __HAVE_PFNMAP_TRACKING
1008 struct pfnmap_track_ctx *pfnmap_track_ctx;
1009#endif
1010} __randomize_layout;
1011
1012/* Clears all bits in the VMA flags bitmap, non-atomically. */
1013static inline void vma_flags_clear_all(vma_flags_t *flags)
1014{
1015 bitmap_zero(ACCESS_PRIVATE(flags, __vma_flags), NUM_VMA_FLAG_BITS);
1016}
1017
1018/*
1019 * Copy value to the first system word of VMA flags, non-atomically.
1020 *
1021 * IMPORTANT: This does not overwrite bytes past the first system word. The
1022 * caller must account for this.
1023 */
1024static inline void vma_flags_overwrite_word(vma_flags_t *flags, unsigned long value)
1025{
1026 *ACCESS_PRIVATE(flags, __vma_flags) = value;
1027}
1028
1029/*
1030 * Copy value to the first system word of VMA flags ONCE, non-atomically.
1031 *
1032 * IMPORTANT: This does not overwrite bytes past the first system word. The
1033 * caller must account for this.
1034 */
1035static inline void vma_flags_overwrite_word_once(vma_flags_t *flags, unsigned long value)
1036{
1037 unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
1038
1039 WRITE_ONCE(*bitmap, value);
1040}
1041
1042/* Update the first system word of VMA flags setting bits, non-atomically. */
1043static inline void vma_flags_set_word(vma_flags_t *flags, unsigned long value)
1044{
1045 unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
1046
1047 *bitmap |= value;
1048}
1049
1050/* Update the first system word of VMA flags clearing bits, non-atomically. */
1051static inline void vma_flags_clear_word(vma_flags_t *flags, unsigned long value)
1052{
1053 unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
1054
1055 *bitmap &= ~value;
1056}
1057
1058#ifdef CONFIG_NUMA
1059#define vma_policy(vma) ((vma)->vm_policy)
1060#else
1061#define vma_policy(vma) NULL
1062#endif
1063
1064/*
1065 * Opaque type representing current mm_struct flag state. Must be accessed via
1066 * mm_flags_xxx() helper functions.
1067 */
1068#define NUM_MM_FLAG_BITS (64)
1069typedef struct {
1070 DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
1071} __private mm_flags_t;
1072
1073struct kioctx_table;
1074struct iommu_mm_data;
1075struct mm_struct {
1076 struct {
1077 /*
1078 * Fields which are often written to are placed in a separate
1079 * cache line.
1080 */
1081 struct {
1082 /**
1083 * @mm_count: The number of references to &struct
1084 * mm_struct (@mm_users count as 1).
1085 *
1086 * Use mmgrab()/mmdrop() to modify. When this drops to
1087 * 0, the &struct mm_struct is freed.
1088 */
1089 atomic_t mm_count;
1090 } ____cacheline_aligned_in_smp;
1091
1092 struct maple_tree mm_mt;
1093
1094 unsigned long mmap_base; /* base of mmap area */
1095 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
1096#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
1097 /* Base addresses for compatible mmap() */
1098 unsigned long mmap_compat_base;
1099 unsigned long mmap_compat_legacy_base;
1100#endif
1101 unsigned long task_size; /* size of task vm space */
1102 pgd_t * pgd;
1103
1104#ifdef CONFIG_MEMBARRIER
1105 /**
1106 * @membarrier_state: Flags controlling membarrier behavior.
1107 *
1108 * This field is close to @pgd to hopefully fit in the same
1109 * cache-line, which needs to be touched by switch_mm().
1110 */
1111 atomic_t membarrier_state;
1112#endif
1113
1114 /**
1115 * @mm_users: The number of users including userspace.
1116 *
1117 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
1118 * drops to 0 (i.e. when the task exits and there are no other
1119 * temporary reference holders), we also release a reference on
1120 * @mm_count (which may then free the &struct mm_struct if
1121 * @mm_count also drops to 0).
1122 */
1123 atomic_t mm_users;
1124
1125 /* MM CID related storage */
1126 struct mm_mm_cid mm_cid;
1127
1128#ifdef CONFIG_MMU
1129 atomic_long_t pgtables_bytes; /* size of all page tables */
1130#endif
1131 int map_count; /* number of VMAs */
1132
1133 spinlock_t page_table_lock; /* Protects page tables and some
1134 * counters
1135 */
1136 /*
1137 * Typically the current mmap_lock's offset is 56 bytes from
1138 * the last cacheline boundary, which is very optimal, as
1139 * its two hot fields 'count' and 'owner' sit in 2 different
1140 * cachelines, and when mmap_lock is highly contended, both
1141 * of the 2 fields will be accessed frequently, current layout
1142 * will help to reduce cache bouncing.
1143 *
1144 * So please be careful with adding new fields before
1145 * mmap_lock, which can easily push the 2 fields into one
1146 * cacheline.
1147 */
1148 struct rw_semaphore mmap_lock;
1149
1150 struct list_head mmlist; /* List of maybe swapped mm's. These
1151 * are globally strung together off
1152 * init_mm.mmlist, and are protected
1153 * by mmlist_lock
1154 */
1155#ifdef CONFIG_PER_VMA_LOCK
1156 struct rcuwait vma_writer_wait;
1157 /*
1158 * This field has lock-like semantics, meaning it is sometimes
1159 * accessed with ACQUIRE/RELEASE semantics.
1160 * Roughly speaking, incrementing the sequence number is
1161 * equivalent to releasing locks on VMAs; reading the sequence
1162 * number can be part of taking a read lock on a VMA.
1163 * Incremented every time mmap_lock is write-locked/unlocked.
1164 * Initialized to 0, therefore odd values indicate mmap_lock
1165 * is write-locked and even values that it's released.
1166 *
1167 * Can be modified under write mmap_lock using RELEASE
1168 * semantics.
1169 * Can be read with no other protection when holding write
1170 * mmap_lock.
1171 * Can be read with ACQUIRE semantics if not holding write
1172 * mmap_lock.
1173 */
1174 seqcount_t mm_lock_seq;
1175#endif
1176#ifdef CONFIG_FUTEX_PRIVATE_HASH
1177 struct mutex futex_hash_lock;
1178 struct futex_private_hash __rcu *futex_phash;
1179 struct futex_private_hash *futex_phash_new;
1180 /* futex-ref */
1181 unsigned long futex_batches;
1182 struct rcu_head futex_rcu;
1183 atomic_long_t futex_atomic;
1184 unsigned int __percpu *futex_ref;
1185#endif
1186
1187 unsigned long hiwater_rss; /* High-watermark of RSS usage */
1188 unsigned long hiwater_vm; /* High-water virtual memory usage */
1189
1190 unsigned long total_vm; /* Total pages mapped */
1191 unsigned long locked_vm; /* Pages that have PG_mlocked set */
1192 atomic64_t pinned_vm; /* Refcount permanently increased */
1193 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
1194 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
1195 unsigned long stack_vm; /* VM_STACK */
1196 vm_flags_t def_flags;
1197
1198 /**
1199 * @write_protect_seq: Locked when any thread is write
1200 * protecting pages mapped by this mm to enforce a later COW,
1201 * for instance during page table copying for fork().
1202 */
1203 seqcount_t write_protect_seq;
1204
1205 spinlock_t arg_lock; /* protect the below fields */
1206
1207 unsigned long start_code, end_code, start_data, end_data;
1208 unsigned long start_brk, brk, start_stack;
1209 unsigned long arg_start, arg_end, env_start, env_end;
1210
1211 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
1212
1213#ifdef CONFIG_ARCH_HAS_ELF_CORE_EFLAGS
1214 /* the ABI-related flags from the ELF header. Used for core dump */
1215 unsigned long saved_e_flags;
1216#endif
1217
1218 struct percpu_counter rss_stat[NR_MM_COUNTERS];
1219
1220 struct linux_binfmt *binfmt;
1221
1222 /* Architecture-specific MM context */
1223 mm_context_t context;
1224
1225 mm_flags_t flags; /* Must use mm_flags_* hlpers to access */
1226
1227#ifdef CONFIG_AIO
1228 spinlock_t ioctx_lock;
1229 struct kioctx_table __rcu *ioctx_table;
1230#endif
1231#ifdef CONFIG_MEMCG
1232 /*
1233 * "owner" points to a task that is regarded as the canonical
1234 * user/owner of this mm. All of the following must be true in
1235 * order for it to be changed:
1236 *
1237 * current == mm->owner
1238 * current->mm != mm
1239 * new_owner->mm == mm
1240 * new_owner->alloc_lock is held
1241 */
1242 struct task_struct __rcu *owner;
1243#endif
1244 struct user_namespace *user_ns;
1245
1246 /* store ref to file /proc/<pid>/exe symlink points to */
1247 struct file __rcu *exe_file;
1248#ifdef CONFIG_MMU_NOTIFIER
1249 struct mmu_notifier_subscriptions *notifier_subscriptions;
1250#endif
1251#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
1252 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
1253#endif
1254#ifdef CONFIG_NUMA_BALANCING
1255 /*
1256 * numa_next_scan is the next time that PTEs will be remapped
1257 * PROT_NONE to trigger NUMA hinting faults; such faults gather
1258 * statistics and migrate pages to new nodes if necessary.
1259 */
1260 unsigned long numa_next_scan;
1261
1262 /* Restart point for scanning and remapping PTEs. */
1263 unsigned long numa_scan_offset;
1264
1265 /* numa_scan_seq prevents two threads remapping PTEs. */
1266 int numa_scan_seq;
1267#endif
1268 /*
1269 * An operation with batched TLB flushing is going on. Anything
1270 * that can move process memory needs to flush the TLB when
1271 * moving a PROT_NONE mapped page.
1272 */
1273 atomic_t tlb_flush_pending;
1274#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
1275 /* See flush_tlb_batched_pending() */
1276 atomic_t tlb_flush_batched;
1277#endif
1278 struct uprobes_state uprobes_state;
1279#ifdef CONFIG_PREEMPT_RT
1280 struct rcu_head delayed_drop;
1281#endif
1282#ifdef CONFIG_HUGETLB_PAGE
1283 atomic_long_t hugetlb_usage;
1284#endif
1285 struct work_struct async_put_work;
1286
1287#ifdef CONFIG_IOMMU_MM_DATA
1288 struct iommu_mm_data *iommu_mm;
1289#endif
1290#ifdef CONFIG_KSM
1291 /*
1292 * Represent how many pages of this process are involved in KSM
1293 * merging (not including ksm_zero_pages).
1294 */
1295 unsigned long ksm_merging_pages;
1296 /*
1297 * Represent how many pages are checked for ksm merging
1298 * including merged and not merged.
1299 */
1300 unsigned long ksm_rmap_items;
1301 /*
1302 * Represent how many empty pages are merged with kernel zero
1303 * pages when enabling KSM use_zero_pages.
1304 */
1305 atomic_long_t ksm_zero_pages;
1306#endif /* CONFIG_KSM */
1307#ifdef CONFIG_LRU_GEN_WALKS_MMU
1308 struct {
1309 /* this mm_struct is on lru_gen_mm_list */
1310 struct list_head list;
1311 /*
1312 * Set when switching to this mm_struct, as a hint of
1313 * whether it has been used since the last time per-node
1314 * page table walkers cleared the corresponding bits.
1315 */
1316 unsigned long bitmap;
1317#ifdef CONFIG_MEMCG
1318 /* points to the memcg of "owner" above */
1319 struct mem_cgroup *memcg;
1320#endif
1321 } lru_gen;
1322#endif /* CONFIG_LRU_GEN_WALKS_MMU */
1323#ifdef CONFIG_MM_ID
1324 mm_id_t mm_id;
1325#endif /* CONFIG_MM_ID */
1326 } __randomize_layout;
1327
1328 /*
1329 * The mm_cpumask needs to be at the end of mm_struct, because it
1330 * is dynamically sized based on nr_cpu_ids.
1331 */
1332 char flexible_array[] __aligned(__alignof__(unsigned long));
1333};
1334
1335/* Copy value to the first system word of mm flags, non-atomically. */
1336static inline void __mm_flags_overwrite_word(struct mm_struct *mm, unsigned long value)
1337{
1338 *ACCESS_PRIVATE(&mm->flags, __mm_flags) = value;
1339}
1340
1341/* Obtain a read-only view of the mm flags bitmap. */
1342static inline const unsigned long *__mm_flags_get_bitmap(const struct mm_struct *mm)
1343{
1344 return (const unsigned long *)ACCESS_PRIVATE(&mm->flags, __mm_flags);
1345}
1346
1347/* Read the first system word of mm flags, non-atomically. */
1348static inline unsigned long __mm_flags_get_word(const struct mm_struct *mm)
1349{
1350 return *__mm_flags_get_bitmap(mm);
1351}
1352
1353/*
1354 * Update the first system word of mm flags ONLY, applying the specified mask to
1355 * it, then setting all flags specified by bits.
1356 */
1357static inline void __mm_flags_set_mask_bits_word(struct mm_struct *mm,
1358 unsigned long mask, unsigned long bits)
1359{
1360 unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
1361
1362 set_mask_bits(bitmap, mask, bits);
1363}
1364
1365#define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
1366 MT_FLAGS_USE_RCU)
1367extern struct mm_struct init_mm;
1368
1369#define MM_STRUCT_FLEXIBLE_ARRAY_INIT \
1370{ \
1371 [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE - 1] = 0 \
1372}
1373
1374/* Pointer magic because the dynamic array size confuses some compilers. */
1375static inline void mm_init_cpumask(struct mm_struct *mm)
1376{
1377 unsigned long cpu_bitmap = (unsigned long)mm;
1378
1379 cpu_bitmap += offsetof(struct mm_struct, flexible_array);
1380 cpumask_clear(dstp: (struct cpumask *)cpu_bitmap);
1381}
1382
1383/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
1384static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
1385{
1386 return (struct cpumask *)&mm->flexible_array;
1387}
1388
1389#ifdef CONFIG_LRU_GEN
1390
1391struct lru_gen_mm_list {
1392 /* mm_struct list for page table walkers */
1393 struct list_head fifo;
1394 /* protects the list above */
1395 spinlock_t lock;
1396};
1397
1398#endif /* CONFIG_LRU_GEN */
1399
1400#ifdef CONFIG_LRU_GEN_WALKS_MMU
1401
1402void lru_gen_add_mm(struct mm_struct *mm);
1403void lru_gen_del_mm(struct mm_struct *mm);
1404void lru_gen_migrate_mm(struct mm_struct *mm);
1405
1406static inline void lru_gen_init_mm(struct mm_struct *mm)
1407{
1408 INIT_LIST_HEAD(list: &mm->lru_gen.list);
1409 mm->lru_gen.bitmap = 0;
1410#ifdef CONFIG_MEMCG
1411 mm->lru_gen.memcg = NULL;
1412#endif
1413}
1414
1415static inline void lru_gen_use_mm(struct mm_struct *mm)
1416{
1417 /*
1418 * When the bitmap is set, page reclaim knows this mm_struct has been
1419 * used since the last time it cleared the bitmap. So it might be worth
1420 * walking the page tables of this mm_struct to clear the accessed bit.
1421 */
1422 WRITE_ONCE(mm->lru_gen.bitmap, -1);
1423}
1424
1425#else /* !CONFIG_LRU_GEN_WALKS_MMU */
1426
1427static inline void lru_gen_add_mm(struct mm_struct *mm)
1428{
1429}
1430
1431static inline void lru_gen_del_mm(struct mm_struct *mm)
1432{
1433}
1434
1435static inline void lru_gen_migrate_mm(struct mm_struct *mm)
1436{
1437}
1438
1439static inline void lru_gen_init_mm(struct mm_struct *mm)
1440{
1441}
1442
1443static inline void lru_gen_use_mm(struct mm_struct *mm)
1444{
1445}
1446
1447#endif /* CONFIG_LRU_GEN_WALKS_MMU */
1448
1449struct vma_iterator {
1450 struct ma_state mas;
1451};
1452
1453#define VMA_ITERATOR(name, __mm, __addr) \
1454 struct vma_iterator name = { \
1455 .mas = { \
1456 .tree = &(__mm)->mm_mt, \
1457 .index = __addr, \
1458 .node = NULL, \
1459 .status = ma_start, \
1460 }, \
1461 }
1462
1463static inline void vma_iter_init(struct vma_iterator *vmi,
1464 struct mm_struct *mm, unsigned long addr)
1465{
1466 mas_init(mas: &vmi->mas, tree: &mm->mm_mt, addr);
1467}
1468
1469#ifdef CONFIG_SCHED_MM_CID
1470/*
1471 * mm_cpus_allowed: Union of all mm's threads allowed CPUs.
1472 */
1473static inline cpumask_t *mm_cpus_allowed(struct mm_struct *mm)
1474{
1475 unsigned long bitmap = (unsigned long)mm;
1476
1477 bitmap += offsetof(struct mm_struct, flexible_array);
1478 /* Skip cpu_bitmap */
1479 bitmap += cpumask_size();
1480 return (struct cpumask *)bitmap;
1481}
1482
1483/* Accessor for struct mm_struct's cidmask. */
1484static inline unsigned long *mm_cidmask(struct mm_struct *mm)
1485{
1486 unsigned long cid_bitmap = (unsigned long)mm_cpus_allowed(mm);
1487
1488 /* Skip mm_cpus_allowed */
1489 cid_bitmap += cpumask_size();
1490 return (unsigned long *)cid_bitmap;
1491}
1492
1493void mm_init_cid(struct mm_struct *mm, struct task_struct *p);
1494
1495static inline int mm_alloc_cid_noprof(struct mm_struct *mm, struct task_struct *p)
1496{
1497 mm->mm_cid.pcpu = alloc_percpu_noprof(struct mm_cid_pcpu);
1498 if (!mm->mm_cid.pcpu)
1499 return -ENOMEM;
1500 mm_init_cid(mm, p);
1501 return 0;
1502}
1503# define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__))
1504
1505static inline void mm_destroy_cid(struct mm_struct *mm)
1506{
1507 free_percpu(pdata: mm->mm_cid.pcpu);
1508 mm->mm_cid.pcpu = NULL;
1509}
1510
1511static inline unsigned int mm_cid_size(void)
1512{
1513 /* mm_cpus_allowed(), mm_cidmask(). */
1514 return cpumask_size() + bitmap_size(num_possible_cpus());
1515}
1516
1517/* Use 2 * NR_CPUS as worse case for static allocation. */
1518# define MM_CID_STATIC_SIZE (2 * sizeof(cpumask_t))
1519#else /* CONFIG_SCHED_MM_CID */
1520static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p) { }
1521static inline int mm_alloc_cid(struct mm_struct *mm, struct task_struct *p) { return 0; }
1522static inline void mm_destroy_cid(struct mm_struct *mm) { }
1523static inline unsigned int mm_cid_size(void)
1524{
1525 return 0;
1526}
1527# define MM_CID_STATIC_SIZE 0
1528#endif /* CONFIG_SCHED_MM_CID */
1529
1530struct mmu_gather;
1531extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
1532extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
1533void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct vm_area_struct *vma);
1534extern void tlb_finish_mmu(struct mmu_gather *tlb);
1535
1536struct vm_fault;
1537
1538/**
1539 * typedef vm_fault_t - Return type for page fault handlers.
1540 *
1541 * Page fault handlers return a bitmask of %VM_FAULT values.
1542 */
1543typedef __bitwise unsigned int vm_fault_t;
1544
1545/**
1546 * enum vm_fault_reason - Page fault handlers return a bitmask of
1547 * these values to tell the core VM what happened when handling the
1548 * fault. Used to decide whether a process gets delivered SIGBUS or
1549 * just gets major/minor fault counters bumped up.
1550 *
1551 * @VM_FAULT_OOM: Out Of Memory
1552 * @VM_FAULT_SIGBUS: Bad access
1553 * @VM_FAULT_MAJOR: Page read from storage
1554 * @VM_FAULT_HWPOISON: Hit poisoned small page
1555 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
1556 * in upper bits
1557 * @VM_FAULT_SIGSEGV: segmentation fault
1558 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
1559 * @VM_FAULT_LOCKED: ->fault locked the returned page
1560 * @VM_FAULT_RETRY: ->fault blocked, must retry
1561 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
1562 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
1563 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
1564 * fsync() to complete (for synchronous page faults
1565 * in DAX)
1566 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released
1567 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
1568 *
1569 */
1570enum vm_fault_reason {
1571 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
1572 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
1573 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
1574 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
1575 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
1576 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
1577 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
1578 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
1579 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
1580 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
1581 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
1582 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
1583 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000,
1584 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
1585};
1586
1587/* Encode hstate index for a hwpoisoned large page */
1588#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
1589#define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
1590
1591#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
1592 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
1593 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
1594
1595#define VM_FAULT_RESULT_TRACE \
1596 { VM_FAULT_OOM, "OOM" }, \
1597 { VM_FAULT_SIGBUS, "SIGBUS" }, \
1598 { VM_FAULT_MAJOR, "MAJOR" }, \
1599 { VM_FAULT_HWPOISON, "HWPOISON" }, \
1600 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
1601 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
1602 { VM_FAULT_NOPAGE, "NOPAGE" }, \
1603 { VM_FAULT_LOCKED, "LOCKED" }, \
1604 { VM_FAULT_RETRY, "RETRY" }, \
1605 { VM_FAULT_FALLBACK, "FALLBACK" }, \
1606 { VM_FAULT_DONE_COW, "DONE_COW" }, \
1607 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \
1608 { VM_FAULT_COMPLETED, "COMPLETED" }
1609
1610struct vm_special_mapping {
1611 const char *name; /* The name, e.g. "[vdso]". */
1612
1613 /*
1614 * If .fault is not provided, this points to a
1615 * NULL-terminated array of pages that back the special mapping.
1616 *
1617 * This must not be NULL unless .fault is provided.
1618 */
1619 struct page **pages;
1620
1621 /*
1622 * If non-NULL, then this is called to resolve page faults
1623 * on the special mapping. If used, .pages is not checked.
1624 */
1625 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
1626 struct vm_area_struct *vma,
1627 struct vm_fault *vmf);
1628
1629 int (*mremap)(const struct vm_special_mapping *sm,
1630 struct vm_area_struct *new_vma);
1631
1632 void (*close)(const struct vm_special_mapping *sm,
1633 struct vm_area_struct *vma);
1634};
1635
1636enum tlb_flush_reason {
1637 TLB_FLUSH_ON_TASK_SWITCH,
1638 TLB_REMOTE_SHOOTDOWN,
1639 TLB_LOCAL_SHOOTDOWN,
1640 TLB_LOCAL_MM_SHOOTDOWN,
1641 TLB_REMOTE_SEND_IPI,
1642 TLB_REMOTE_WRONG_CPU,
1643};
1644
1645/**
1646 * enum fault_flag - Fault flag definitions.
1647 * @FAULT_FLAG_WRITE: Fault was a write fault.
1648 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
1649 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
1650 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
1651 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
1652 * @FAULT_FLAG_TRIED: The fault has been tried once.
1653 * @FAULT_FLAG_USER: The fault originated in userspace.
1654 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
1655 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
1656 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
1657 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a
1658 * COW mapping, making sure that an exclusive anon page is
1659 * mapped after the fault.
1660 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
1661 * We should only access orig_pte if this flag set.
1662 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock.
1663 *
1664 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
1665 * whether we would allow page faults to retry by specifying these two
1666 * fault flags correctly. Currently there can be three legal combinations:
1667 *
1668 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
1669 * this is the first try
1670 *
1671 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
1672 * we've already tried at least once
1673 *
1674 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
1675 *
1676 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
1677 * be used. Note that page faults can be allowed to retry for multiple times,
1678 * in which case we'll have an initial fault with flags (a) then later on
1679 * continuous faults with flags (b). We should always try to detect pending
1680 * signals before a retry to make sure the continuous page faults can still be
1681 * interrupted if necessary.
1682 *
1683 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
1684 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
1685 * applied to mappings that are not COW mappings.
1686 */
1687enum fault_flag {
1688 FAULT_FLAG_WRITE = 1 << 0,
1689 FAULT_FLAG_MKWRITE = 1 << 1,
1690 FAULT_FLAG_ALLOW_RETRY = 1 << 2,
1691 FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
1692 FAULT_FLAG_KILLABLE = 1 << 4,
1693 FAULT_FLAG_TRIED = 1 << 5,
1694 FAULT_FLAG_USER = 1 << 6,
1695 FAULT_FLAG_REMOTE = 1 << 7,
1696 FAULT_FLAG_INSTRUCTION = 1 << 8,
1697 FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
1698 FAULT_FLAG_UNSHARE = 1 << 10,
1699 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11,
1700 FAULT_FLAG_VMA_LOCK = 1 << 12,
1701};
1702
1703typedef unsigned int __bitwise zap_flags_t;
1704
1705/* Flags for clear_young_dirty_ptes(). */
1706typedef int __bitwise cydp_t;
1707
1708/* Clear the access bit */
1709#define CYDP_CLEAR_YOUNG ((__force cydp_t)BIT(0))
1710
1711/* Clear the dirty bit */
1712#define CYDP_CLEAR_DIRTY ((__force cydp_t)BIT(1))
1713
1714/*
1715 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
1716 * other. Here is what they mean, and how to use them:
1717 *
1718 *
1719 * FIXME: For pages which are part of a filesystem, mappings are subject to the
1720 * lifetime enforced by the filesystem and we need guarantees that longterm
1721 * users like RDMA and V4L2 only establish mappings which coordinate usage with
1722 * the filesystem. Ideas for this coordination include revoking the longterm
1723 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was
1724 * added after the problem with filesystems was found FS DAX VMAs are
1725 * specifically failed. Filesystem pages are still subject to bugs and use of
1726 * FOLL_LONGTERM should be avoided on those pages.
1727 *
1728 * In the CMA case: long term pins in a CMA region would unnecessarily fragment
1729 * that region. And so, CMA attempts to migrate the page before pinning, when
1730 * FOLL_LONGTERM is specified.
1731 *
1732 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
1733 * but an additional pin counting system) will be invoked. This is intended for
1734 * anything that gets a page reference and then touches page data (for example,
1735 * Direct IO). This lets the filesystem know that some non-file-system entity is
1736 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages
1737 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by
1738 * a call to unpin_user_page().
1739 *
1740 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
1741 * and separate refcounting mechanisms, however, and that means that each has
1742 * its own acquire and release mechanisms:
1743 *
1744 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
1745 *
1746 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
1747 *
1748 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
1749 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
1750 * calls applied to them, and that's perfectly OK. This is a constraint on the
1751 * callers, not on the pages.)
1752 *
1753 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
1754 * directly by the caller. That's in order to help avoid mismatches when
1755 * releasing pages: get_user_pages*() pages must be released via put_page(),
1756 * while pin_user_pages*() pages must be released via unpin_user_page().
1757 *
1758 * Please see Documentation/core-api/pin_user_pages.rst for more information.
1759 */
1760
1761enum {
1762 /* check pte is writable */
1763 FOLL_WRITE = 1 << 0,
1764 /* do get_page on page */
1765 FOLL_GET = 1 << 1,
1766 /* give error on hole if it would be zero */
1767 FOLL_DUMP = 1 << 2,
1768 /* get_user_pages read/write w/o permission */
1769 FOLL_FORCE = 1 << 3,
1770 /*
1771 * if a disk transfer is needed, start the IO and return without waiting
1772 * upon it
1773 */
1774 FOLL_NOWAIT = 1 << 4,
1775 /* do not fault in pages */
1776 FOLL_NOFAULT = 1 << 5,
1777 /* check page is hwpoisoned */
1778 FOLL_HWPOISON = 1 << 6,
1779 /* don't do file mappings */
1780 FOLL_ANON = 1 << 7,
1781 /*
1782 * FOLL_LONGTERM indicates that the page will be held for an indefinite
1783 * time period _often_ under userspace control. This is in contrast to
1784 * iov_iter_get_pages(), whose usages are transient.
1785 */
1786 FOLL_LONGTERM = 1 << 8,
1787 /* split huge pmd before returning */
1788 FOLL_SPLIT_PMD = 1 << 9,
1789 /* allow returning PCI P2PDMA pages */
1790 FOLL_PCI_P2PDMA = 1 << 10,
1791 /* allow interrupts from generic signals */
1792 FOLL_INTERRUPTIBLE = 1 << 11,
1793 /*
1794 * Always honor (trigger) NUMA hinting faults.
1795 *
1796 * FOLL_WRITE implicitly honors NUMA hinting faults because a
1797 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE
1798 * apply). get_user_pages_fast_only() always implicitly honors NUMA
1799 * hinting faults.
1800 */
1801 FOLL_HONOR_NUMA_FAULT = 1 << 12,
1802
1803 /* See also internal only FOLL flags in mm/internal.h */
1804};
1805
1806/* mm flags */
1807
1808/*
1809 * The first two bits represent core dump modes for set-user-ID,
1810 * the modes are SUID_DUMP_* defined in linux/sched/coredump.h
1811 */
1812#define MMF_DUMPABLE_BITS 2
1813#define MMF_DUMPABLE_MASK (BIT(MMF_DUMPABLE_BITS) - 1)
1814/* coredump filter bits */
1815#define MMF_DUMP_ANON_PRIVATE 2
1816#define MMF_DUMP_ANON_SHARED 3
1817#define MMF_DUMP_MAPPED_PRIVATE 4
1818#define MMF_DUMP_MAPPED_SHARED 5
1819#define MMF_DUMP_ELF_HEADERS 6
1820#define MMF_DUMP_HUGETLB_PRIVATE 7
1821#define MMF_DUMP_HUGETLB_SHARED 8
1822#define MMF_DUMP_DAX_PRIVATE 9
1823#define MMF_DUMP_DAX_SHARED 10
1824
1825#define MMF_DUMP_FILTER_SHIFT MMF_DUMPABLE_BITS
1826#define MMF_DUMP_FILTER_BITS 9
1827#define MMF_DUMP_FILTER_MASK \
1828 ((BIT(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
1829#define MMF_DUMP_FILTER_DEFAULT \
1830 (BIT(MMF_DUMP_ANON_PRIVATE) | BIT(MMF_DUMP_ANON_SHARED) | \
1831 BIT(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
1832
1833#ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
1834# define MMF_DUMP_MASK_DEFAULT_ELF BIT(MMF_DUMP_ELF_HEADERS)
1835#else
1836# define MMF_DUMP_MASK_DEFAULT_ELF 0
1837#endif
1838 /* leave room for more dump flags */
1839#define MMF_VM_MERGEABLE 16 /* KSM may merge identical pages */
1840#define MMF_VM_HUGEPAGE 17 /* set when mm is available for khugepaged */
1841
1842#define MMF_HUGE_ZERO_FOLIO 18 /* mm has ever used the global huge zero folio */
1843
1844#define MMF_HAS_UPROBES 19 /* has uprobes */
1845#define MMF_RECALC_UPROBES 20 /* MMF_HAS_UPROBES can be wrong */
1846#define MMF_OOM_SKIP 21 /* mm is of no interest for the OOM killer */
1847#define MMF_UNSTABLE 22 /* mm is unstable for copy_from_user */
1848#define MMF_DISABLE_THP_EXCEPT_ADVISED 23 /* no THP except when advised (e.g., VM_HUGEPAGE) */
1849#define MMF_DISABLE_THP_COMPLETELY 24 /* no THP for all VMAs */
1850#define MMF_DISABLE_THP_MASK (BIT(MMF_DISABLE_THP_COMPLETELY) | \
1851 BIT(MMF_DISABLE_THP_EXCEPT_ADVISED))
1852#define MMF_OOM_REAP_QUEUED 25 /* mm was queued for oom_reaper */
1853#define MMF_MULTIPROCESS 26 /* mm is shared between processes */
1854/*
1855 * MMF_HAS_PINNED: Whether this mm has pinned any pages. This can be either
1856 * replaced in the future by mm.pinned_vm when it becomes stable, or grow into
1857 * a counter on its own. We're aggresive on this bit for now: even if the
1858 * pinned pages were unpinned later on, we'll still keep this bit set for the
1859 * lifecycle of this mm, just for simplicity.
1860 */
1861#define MMF_HAS_PINNED 27 /* FOLL_PIN has run, never cleared */
1862
1863#define MMF_HAS_MDWE 28
1864#define MMF_HAS_MDWE_MASK BIT(MMF_HAS_MDWE)
1865
1866#define MMF_HAS_MDWE_NO_INHERIT 29
1867
1868#define MMF_VM_MERGE_ANY 30
1869#define MMF_VM_MERGE_ANY_MASK BIT(MMF_VM_MERGE_ANY)
1870
1871#define MMF_TOPDOWN 31 /* mm searches top down by default */
1872#define MMF_TOPDOWN_MASK BIT(MMF_TOPDOWN)
1873
1874#define MMF_INIT_LEGACY_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
1875 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
1876 MMF_VM_MERGE_ANY_MASK | MMF_TOPDOWN_MASK)
1877
1878/* Legacy flags must fit within 32 bits. */
1879static_assert((u64)MMF_INIT_LEGACY_MASK <= (u64)UINT_MAX);
1880
1881/*
1882 * Initialise legacy flags according to masks, propagating selected flags on
1883 * fork. Further flag manipulation can be performed by the caller.
1884 */
1885static inline unsigned long mmf_init_legacy_flags(unsigned long flags)
1886{
1887 if (flags & (1UL << MMF_HAS_MDWE_NO_INHERIT))
1888 flags &= ~((1UL << MMF_HAS_MDWE) |
1889 (1UL << MMF_HAS_MDWE_NO_INHERIT));
1890 return flags & MMF_INIT_LEGACY_MASK;
1891}
1892
1893#endif /* _LINUX_MM_TYPES_H */
1894

source code of linux/include/linux/mm_types.h