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
22 #include <asm/mmu.h>
23
24 #ifndef AT_VECTOR_SIZE_ARCH
25 #define AT_VECTOR_SIZE_ARCH 0
26 #endif
27 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
28
29 #define INIT_PASID 0
30
31 struct address_space;
32 struct mem_cgroup;
33
34 /*
35 * Each physical page in the system has a struct page associated with
36 * it to keep track of whatever it is we are using the page for at the
37 * moment. Note that we have no way to track which tasks are using
38 * a page, though if it is a pagecache page, rmap structures can tell us
39 * who is mapping it.
40 *
41 * If you allocate the page using alloc_pages(), you can use some of the
42 * space in struct page for your own purposes. The five words in the main
43 * union are available, except for bit 0 of the first word which must be
44 * kept clear. Many users use this word to store a pointer to an object
45 * which is guaranteed to be aligned. If you use the same storage as
46 * page->mapping, you must restore it to NULL before freeing the page.
47 *
48 * If your page will not be mapped to userspace, you can also use the four
49 * bytes in the mapcount union, but you must call page_mapcount_reset()
50 * before freeing it.
51 *
52 * If you want to use the refcount field, it must be used in such a way
53 * that other CPUs temporarily incrementing and then decrementing the
54 * refcount does not cause problems. On receiving the page from
55 * alloc_pages(), the refcount will be positive.
56 *
57 * If you allocate pages of order > 0, you can use some of the fields
58 * in each subpage, but you may need to restore some of their values
59 * afterwards.
60 *
61 * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
62 * That requires that freelist & counters in struct slab be adjacent and
63 * double-word aligned. Because struct slab currently just reinterprets the
64 * bits of struct page, we align all struct pages to double-word boundaries,
65 * and ensure that 'freelist' is aligned within struct slab.
66 */
67 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
68 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
69 #else
70 #define _struct_page_alignment
71 #endif
72
73 struct page {
74 unsigned long flags; /* Atomic flags, some possibly
75 * updated asynchronously */
76 /*
77 * Five words (20/40 bytes) are available in this union.
78 * WARNING: bit 0 of the first word is used for PageTail(). That
79 * means the other users of this union MUST NOT use the bit to
80 * avoid collision and false-positive PageTail().
81 */
82 union {
83 struct { /* Page cache and anonymous pages */
84 /**
85 * @lru: Pageout list, eg. active_list protected by
86 * lruvec->lru_lock. Sometimes used as a generic list
87 * by the page owner.
88 */
89 union {
90 struct list_head lru;
91
92 /* Or, for the Unevictable "LRU list" slot */
93 struct {
94 /* Always even, to negate PageTail */
95 void *__filler;
96 /* Count page's or folio's mlocks */
97 unsigned int mlock_count;
98 };
99
100 /* Or, free page */
101 struct list_head buddy_list;
102 struct list_head pcp_list;
103 };
104 /* See page-flags.h for PAGE_MAPPING_FLAGS */
105 struct address_space *mapping;
106 pgoff_t index; /* Our offset within mapping. */
107 /**
108 * @private: Mapping-private opaque data.
109 * Usually used for buffer_heads if PagePrivate.
110 * Used for swp_entry_t if PageSwapCache.
111 * Indicates order in the buddy system if PageBuddy.
112 */
113 unsigned long private;
114 };
115 struct { /* page_pool used by netstack */
116 /**
117 * @pp_magic: magic value to avoid recycling non
118 * page_pool allocated pages.
119 */
120 unsigned long pp_magic;
121 struct page_pool *pp;
122 unsigned long _pp_mapping_pad;
123 unsigned long dma_addr;
124 union {
125 /**
126 * dma_addr_upper: might require a 64-bit
127 * value on 32-bit architectures.
128 */
129 unsigned long dma_addr_upper;
130 /**
131 * For frag page support, not supported in
132 * 32-bit architectures with 64-bit DMA.
133 */
134 atomic_long_t pp_frag_count;
135 };
136 };
137 struct { /* Tail pages of compound page */
138 unsigned long compound_head; /* Bit zero is set */
139
140 /* First tail page only */
141 unsigned char compound_dtor;
142 unsigned char compound_order;
143 atomic_t compound_mapcount;
144 atomic_t compound_pincount;
145 #ifdef CONFIG_64BIT
146 unsigned int compound_nr; /* 1 << compound_order */
147 #endif
148 };
149 struct { /* Second tail page of compound page */
150 unsigned long _compound_pad_1; /* compound_head */
151 unsigned long _compound_pad_2;
152 /* For both global and memcg */
153 struct list_head deferred_list;
154 };
155 struct { /* Page table pages */
156 unsigned long _pt_pad_1; /* compound_head */
157 pgtable_t pmd_huge_pte; /* protected by page->ptl */
158 unsigned long _pt_pad_2; /* mapping */
159 union {
160 struct mm_struct *pt_mm; /* x86 pgds only */
161 atomic_t pt_frag_refcount; /* powerpc */
162 };
163 #if ALLOC_SPLIT_PTLOCKS
164 spinlock_t *ptl;
165 #else
166 spinlock_t ptl;
167 #endif
168 };
169 struct { /* ZONE_DEVICE pages */
170 /** @pgmap: Points to the hosting device page map. */
171 struct dev_pagemap *pgmap;
172 void *zone_device_data;
173 /*
174 * ZONE_DEVICE private pages are counted as being
175 * mapped so the next 3 words hold the mapping, index,
176 * and private fields from the source anonymous or
177 * page cache page while the page is migrated to device
178 * private memory.
179 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
180 * use the mapping, index, and private fields when
181 * pmem backed DAX files are mapped.
182 */
183 };
184
185 /** @rcu_head: You can use this to free a page by RCU. */
186 struct rcu_head rcu_head;
187 };
188
189 union { /* This union is 4 bytes in size. */
190 /*
191 * If the page can be mapped to userspace, encodes the number
192 * of times this page is referenced by a page table.
193 */
194 atomic_t _mapcount;
195
196 /*
197 * If the page is neither PageSlab nor mappable to userspace,
198 * the value stored here may help determine what this page
199 * is used for. See page-flags.h for a list of page types
200 * which are currently stored here.
201 */
202 unsigned int page_type;
203 };
204
205 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
206 atomic_t _refcount;
207
208 #ifdef CONFIG_MEMCG
209 unsigned long memcg_data;
210 #endif
211
212 /*
213 * On machines where all RAM is mapped into kernel address space,
214 * we can simply calculate the virtual address. On machines with
215 * highmem some memory is mapped into kernel virtual memory
216 * dynamically, so we need a place to store that address.
217 * Note that this field could be 16 bits on x86 ... ;)
218 *
219 * Architectures with slow multiplication can define
220 * WANT_PAGE_VIRTUAL in asm/page.h
221 */
222 #if defined(WANT_PAGE_VIRTUAL)
223 void *virtual; /* Kernel virtual address (NULL if
224 not kmapped, ie. highmem) */
225 #endif /* WANT_PAGE_VIRTUAL */
226
227 #ifdef CONFIG_KMSAN
228 /*
229 * KMSAN metadata for this page:
230 * - shadow page: every bit indicates whether the corresponding
231 * bit of the original page is initialized (0) or not (1);
232 * - origin page: every 4 bytes contain an id of the stack trace
233 * where the uninitialized value was created.
234 */
235 struct page *kmsan_shadow;
236 struct page *kmsan_origin;
237 #endif
238
239 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
240 int _last_cpupid;
241 #endif
242 } _struct_page_alignment;
243
244 /**
245 * struct folio - Represents a contiguous set of bytes.
246 * @flags: Identical to the page flags.
247 * @lru: Least Recently Used list; tracks how recently this folio was used.
248 * @mlock_count: Number of times this folio has been pinned by mlock().
249 * @mapping: The file this page belongs to, or refers to the anon_vma for
250 * anonymous memory.
251 * @index: Offset within the file, in units of pages. For anonymous memory,
252 * this is the index from the beginning of the mmap.
253 * @private: Filesystem per-folio data (see folio_attach_private()).
254 * Used for swp_entry_t if folio_test_swapcache().
255 * @_mapcount: Do not access this member directly. Use folio_mapcount() to
256 * find out how many times this folio is mapped by userspace.
257 * @_refcount: Do not access this member directly. Use folio_ref_count()
258 * to find how many references there are to this folio.
259 * @memcg_data: Memory Control Group data.
260 * @_flags_1: For large folios, additional page flags.
261 * @__head: Points to the folio. Do not use.
262 * @_folio_dtor: Which destructor to use for this folio.
263 * @_folio_order: Do not use directly, call folio_order().
264 * @_total_mapcount: Do not use directly, call folio_entire_mapcount().
265 * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
266 * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
267 *
268 * A folio is a physically, virtually and logically contiguous set
269 * of bytes. It is a power-of-two in size, and it is aligned to that
270 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is
271 * in the page cache, it is at a file offset which is a multiple of that
272 * power-of-two. It may be mapped into userspace at an address which is
273 * at an arbitrary page offset, but its kernel virtual address is aligned
274 * to its size.
275 */
276 struct folio {
277 /* private: don't document the anon union */
278 union {
279 struct {
280 /* public: */
281 unsigned long flags;
282 union {
283 struct list_head lru;
284 /* private: avoid cluttering the output */
285 struct {
286 void *__filler;
287 /* public: */
288 unsigned int mlock_count;
289 /* private: */
290 };
291 /* public: */
292 };
293 struct address_space *mapping;
294 pgoff_t index;
295 void *private;
296 atomic_t _mapcount;
297 atomic_t _refcount;
298 #ifdef CONFIG_MEMCG
299 unsigned long memcg_data;
300 #endif
301 /* private: the union with struct page is transitional */
302 };
303 struct page page;
304 };
305 unsigned long _flags_1;
306 unsigned long __head;
307 unsigned char _folio_dtor;
308 unsigned char _folio_order;
309 atomic_t _total_mapcount;
310 atomic_t _pincount;
311 #ifdef CONFIG_64BIT
312 unsigned int _folio_nr_pages;
313 #endif
314 };
315
316 #define FOLIO_MATCH(pg, fl) \
317 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
318 FOLIO_MATCH(flags, flags);
319 FOLIO_MATCH(lru, lru);
320 FOLIO_MATCH(mapping, mapping);
321 FOLIO_MATCH(compound_head, lru);
322 FOLIO_MATCH(index, index);
323 FOLIO_MATCH(private, private);
324 FOLIO_MATCH(_mapcount, _mapcount);
325 FOLIO_MATCH(_refcount, _refcount);
326 #ifdef CONFIG_MEMCG
327 FOLIO_MATCH(memcg_data, memcg_data);
328 #endif
329 #undef FOLIO_MATCH
330 #define FOLIO_MATCH(pg, fl) \
331 static_assert(offsetof(struct folio, fl) == \
332 offsetof(struct page, pg) + sizeof(struct page))
333 FOLIO_MATCH(flags, _flags_1);
334 FOLIO_MATCH(compound_head, __head);
335 FOLIO_MATCH(compound_dtor, _folio_dtor);
336 FOLIO_MATCH(compound_order, _folio_order);
337 FOLIO_MATCH(compound_mapcount, _total_mapcount);
338 FOLIO_MATCH(compound_pincount, _pincount);
339 #ifdef CONFIG_64BIT
340 FOLIO_MATCH(compound_nr, _folio_nr_pages);
341 #endif
342 #undef FOLIO_MATCH
343
folio_mapcount_ptr(struct folio * folio)344 static inline atomic_t *folio_mapcount_ptr(struct folio *folio)
345 {
346 struct page *tail = &folio->page + 1;
347 return &tail->compound_mapcount;
348 }
349
compound_mapcount_ptr(struct page * page)350 static inline atomic_t *compound_mapcount_ptr(struct page *page)
351 {
352 return &page[1].compound_mapcount;
353 }
354
compound_pincount_ptr(struct page * page)355 static inline atomic_t *compound_pincount_ptr(struct page *page)
356 {
357 return &page[1].compound_pincount;
358 }
359
360 /*
361 * Used for sizing the vmemmap region on some architectures
362 */
363 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
364
365 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
366 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
367
368 /*
369 * page_private can be used on tail pages. However, PagePrivate is only
370 * checked by the VM on the head page. So page_private on the tail pages
371 * should be used for data that's ancillary to the head page (eg attaching
372 * buffer heads to tail pages after attaching buffer heads to the head page)
373 */
374 #define page_private(page) ((page)->private)
375
set_page_private(struct page * page,unsigned long private)376 static inline void set_page_private(struct page *page, unsigned long private)
377 {
378 page->private = private;
379 }
380
folio_get_private(struct folio * folio)381 static inline void *folio_get_private(struct folio *folio)
382 {
383 return folio->private;
384 }
385
386 struct page_frag_cache {
387 void * va;
388 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
389 __u16 offset;
390 __u16 size;
391 #else
392 __u32 offset;
393 #endif
394 /* we maintain a pagecount bias, so that we dont dirty cache line
395 * containing page->_refcount every time we allocate a fragment.
396 */
397 unsigned int pagecnt_bias;
398 bool pfmemalloc;
399 };
400
401 typedef unsigned long vm_flags_t;
402
403 /*
404 * A region containing a mapping of a non-memory backed file under NOMMU
405 * conditions. These are held in a global tree and are pinned by the VMAs that
406 * map parts of them.
407 */
408 struct vm_region {
409 struct rb_node vm_rb; /* link in global region tree */
410 vm_flags_t vm_flags; /* VMA vm_flags */
411 unsigned long vm_start; /* start address of region */
412 unsigned long vm_end; /* region initialised to here */
413 unsigned long vm_top; /* region allocated to here */
414 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
415 struct file *vm_file; /* the backing file or NULL */
416
417 int vm_usage; /* region usage count (access under nommu_region_sem) */
418 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
419 * this region */
420 };
421
422 #ifdef CONFIG_USERFAULTFD
423 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
424 struct vm_userfaultfd_ctx {
425 struct userfaultfd_ctx *ctx;
426 };
427 #else /* CONFIG_USERFAULTFD */
428 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
429 struct vm_userfaultfd_ctx {};
430 #endif /* CONFIG_USERFAULTFD */
431
432 struct anon_vma_name {
433 struct kref kref;
434 /* The name needs to be at the end because it is dynamically sized. */
435 char name[];
436 };
437
438 /*
439 * This struct describes a virtual memory area. There is one of these
440 * per VM-area/task. A VM area is any part of the process virtual memory
441 * space that has a special rule for the page-fault handlers (ie a shared
442 * library, the executable area etc).
443 */
444 struct vm_area_struct {
445 /* The first cache line has the info for VMA tree walking. */
446
447 unsigned long vm_start; /* Our start address within vm_mm. */
448 unsigned long vm_end; /* The first byte after our end address
449 within vm_mm. */
450
451 struct mm_struct *vm_mm; /* The address space we belong to. */
452
453 /*
454 * Access permissions of this VMA.
455 * See vmf_insert_mixed_prot() for discussion.
456 */
457 pgprot_t vm_page_prot;
458 unsigned long vm_flags; /* Flags, see mm.h. */
459
460 /*
461 * For areas with an address space and backing store,
462 * linkage into the address_space->i_mmap interval tree.
463 *
464 * For private anonymous mappings, a pointer to a null terminated string
465 * containing the name given to the vma, or NULL if unnamed.
466 */
467
468 union {
469 struct {
470 struct rb_node rb;
471 unsigned long rb_subtree_last;
472 } shared;
473 /*
474 * Serialized by mmap_sem. Never use directly because it is
475 * valid only when vm_file is NULL. Use anon_vma_name instead.
476 */
477 struct anon_vma_name *anon_name;
478 };
479
480 /*
481 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
482 * list, after a COW of one of the file pages. A MAP_SHARED vma
483 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
484 * or brk vma (with NULL file) can only be in an anon_vma list.
485 */
486 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
487 * page_table_lock */
488 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
489
490 /* Function pointers to deal with this struct. */
491 const struct vm_operations_struct *vm_ops;
492
493 /* Information about our backing store: */
494 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
495 units */
496 struct file * vm_file; /* File we map to (can be NULL). */
497 void * vm_private_data; /* was vm_pte (shared mem) */
498
499 #ifdef CONFIG_SWAP
500 atomic_long_t swap_readahead_info;
501 #endif
502 #ifndef CONFIG_MMU
503 struct vm_region *vm_region; /* NOMMU mapping region */
504 #endif
505 #ifdef CONFIG_NUMA
506 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
507 #endif
508 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
509 } __randomize_layout;
510
511 struct kioctx_table;
512 struct mm_struct {
513 struct {
514 struct maple_tree mm_mt;
515 #ifdef CONFIG_MMU
516 unsigned long (*get_unmapped_area) (struct file *filp,
517 unsigned long addr, unsigned long len,
518 unsigned long pgoff, unsigned long flags);
519 #endif
520 unsigned long mmap_base; /* base of mmap area */
521 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
522 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
523 /* Base addresses for compatible mmap() */
524 unsigned long mmap_compat_base;
525 unsigned long mmap_compat_legacy_base;
526 #endif
527 unsigned long task_size; /* size of task vm space */
528 pgd_t * pgd;
529
530 #ifdef CONFIG_MEMBARRIER
531 /**
532 * @membarrier_state: Flags controlling membarrier behavior.
533 *
534 * This field is close to @pgd to hopefully fit in the same
535 * cache-line, which needs to be touched by switch_mm().
536 */
537 atomic_t membarrier_state;
538 #endif
539
540 /**
541 * @mm_users: The number of users including userspace.
542 *
543 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
544 * drops to 0 (i.e. when the task exits and there are no other
545 * temporary reference holders), we also release a reference on
546 * @mm_count (which may then free the &struct mm_struct if
547 * @mm_count also drops to 0).
548 */
549 atomic_t mm_users;
550
551 /**
552 * @mm_count: The number of references to &struct mm_struct
553 * (@mm_users count as 1).
554 *
555 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
556 * &struct mm_struct is freed.
557 */
558 atomic_t mm_count;
559
560 #ifdef CONFIG_MMU
561 atomic_long_t pgtables_bytes; /* PTE page table pages */
562 #endif
563 int map_count; /* number of VMAs */
564
565 spinlock_t page_table_lock; /* Protects page tables and some
566 * counters
567 */
568 /*
569 * With some kernel config, the current mmap_lock's offset
570 * inside 'mm_struct' is at 0x120, which is very optimal, as
571 * its two hot fields 'count' and 'owner' sit in 2 different
572 * cachelines, and when mmap_lock is highly contended, both
573 * of the 2 fields will be accessed frequently, current layout
574 * will help to reduce cache bouncing.
575 *
576 * So please be careful with adding new fields before
577 * mmap_lock, which can easily push the 2 fields into one
578 * cacheline.
579 */
580 struct rw_semaphore mmap_lock;
581
582 struct list_head mmlist; /* List of maybe swapped mm's. These
583 * are globally strung together off
584 * init_mm.mmlist, and are protected
585 * by mmlist_lock
586 */
587
588
589 unsigned long hiwater_rss; /* High-watermark of RSS usage */
590 unsigned long hiwater_vm; /* High-water virtual memory usage */
591
592 unsigned long total_vm; /* Total pages mapped */
593 unsigned long locked_vm; /* Pages that have PG_mlocked set */
594 atomic64_t pinned_vm; /* Refcount permanently increased */
595 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
596 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
597 unsigned long stack_vm; /* VM_STACK */
598 unsigned long def_flags;
599
600 /**
601 * @write_protect_seq: Locked when any thread is write
602 * protecting pages mapped by this mm to enforce a later COW,
603 * for instance during page table copying for fork().
604 */
605 seqcount_t write_protect_seq;
606
607 spinlock_t arg_lock; /* protect the below fields */
608
609 unsigned long start_code, end_code, start_data, end_data;
610 unsigned long start_brk, brk, start_stack;
611 unsigned long arg_start, arg_end, env_start, env_end;
612
613 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
614
615 /*
616 * Special counters, in some configurations protected by the
617 * page_table_lock, in other configurations by being atomic.
618 */
619 struct mm_rss_stat rss_stat;
620
621 struct linux_binfmt *binfmt;
622
623 /* Architecture-specific MM context */
624 mm_context_t context;
625
626 unsigned long flags; /* Must use atomic bitops to access */
627
628 #ifdef CONFIG_AIO
629 spinlock_t ioctx_lock;
630 struct kioctx_table __rcu *ioctx_table;
631 #endif
632 #ifdef CONFIG_MEMCG
633 /*
634 * "owner" points to a task that is regarded as the canonical
635 * user/owner of this mm. All of the following must be true in
636 * order for it to be changed:
637 *
638 * current == mm->owner
639 * current->mm != mm
640 * new_owner->mm == mm
641 * new_owner->alloc_lock is held
642 */
643 struct task_struct __rcu *owner;
644 #endif
645 struct user_namespace *user_ns;
646
647 /* store ref to file /proc/<pid>/exe symlink points to */
648 struct file __rcu *exe_file;
649 #ifdef CONFIG_MMU_NOTIFIER
650 struct mmu_notifier_subscriptions *notifier_subscriptions;
651 #endif
652 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
653 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
654 #endif
655 #ifdef CONFIG_NUMA_BALANCING
656 /*
657 * numa_next_scan is the next time that PTEs will be remapped
658 * PROT_NONE to trigger NUMA hinting faults; such faults gather
659 * statistics and migrate pages to new nodes if necessary.
660 */
661 unsigned long numa_next_scan;
662
663 /* Restart point for scanning and remapping PTEs. */
664 unsigned long numa_scan_offset;
665
666 /* numa_scan_seq prevents two threads remapping PTEs. */
667 int numa_scan_seq;
668 #endif
669 /*
670 * An operation with batched TLB flushing is going on. Anything
671 * that can move process memory needs to flush the TLB when
672 * moving a PROT_NONE mapped page.
673 */
674 atomic_t tlb_flush_pending;
675 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
676 /* See flush_tlb_batched_pending() */
677 atomic_t tlb_flush_batched;
678 #endif
679 struct uprobes_state uprobes_state;
680 #ifdef CONFIG_PREEMPT_RT
681 struct rcu_head delayed_drop;
682 #endif
683 #ifdef CONFIG_HUGETLB_PAGE
684 atomic_long_t hugetlb_usage;
685 #endif
686 struct work_struct async_put_work;
687
688 #ifdef CONFIG_IOMMU_SVA
689 u32 pasid;
690 #endif
691 #ifdef CONFIG_KSM
692 /*
693 * Represent how many pages of this process are involved in KSM
694 * merging.
695 */
696 unsigned long ksm_merging_pages;
697 /*
698 * Represent how many pages are checked for ksm merging
699 * including merged and not merged.
700 */
701 unsigned long ksm_rmap_items;
702 #endif
703 #ifdef CONFIG_LRU_GEN
704 struct {
705 /* this mm_struct is on lru_gen_mm_list */
706 struct list_head list;
707 /*
708 * Set when switching to this mm_struct, as a hint of
709 * whether it has been used since the last time per-node
710 * page table walkers cleared the corresponding bits.
711 */
712 unsigned long bitmap;
713 #ifdef CONFIG_MEMCG
714 /* points to the memcg of "owner" above */
715 struct mem_cgroup *memcg;
716 #endif
717 } lru_gen;
718 #endif /* CONFIG_LRU_GEN */
719 } __randomize_layout;
720
721 /*
722 * The mm_cpumask needs to be at the end of mm_struct, because it
723 * is dynamically sized based on nr_cpu_ids.
724 */
725 unsigned long cpu_bitmap[];
726 };
727
728 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN)
729 extern struct mm_struct init_mm;
730
731 /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)732 static inline void mm_init_cpumask(struct mm_struct *mm)
733 {
734 unsigned long cpu_bitmap = (unsigned long)mm;
735
736 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
737 cpumask_clear((struct cpumask *)cpu_bitmap);
738 }
739
740 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)741 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
742 {
743 return (struct cpumask *)&mm->cpu_bitmap;
744 }
745
746 #ifdef CONFIG_LRU_GEN
747
748 struct lru_gen_mm_list {
749 /* mm_struct list for page table walkers */
750 struct list_head fifo;
751 /* protects the list above */
752 spinlock_t lock;
753 };
754
755 void lru_gen_add_mm(struct mm_struct *mm);
756 void lru_gen_del_mm(struct mm_struct *mm);
757 #ifdef CONFIG_MEMCG
758 void lru_gen_migrate_mm(struct mm_struct *mm);
759 #endif
760
lru_gen_init_mm(struct mm_struct * mm)761 static inline void lru_gen_init_mm(struct mm_struct *mm)
762 {
763 INIT_LIST_HEAD(&mm->lru_gen.list);
764 mm->lru_gen.bitmap = 0;
765 #ifdef CONFIG_MEMCG
766 mm->lru_gen.memcg = NULL;
767 #endif
768 }
769
lru_gen_use_mm(struct mm_struct * mm)770 static inline void lru_gen_use_mm(struct mm_struct *mm)
771 {
772 /*
773 * When the bitmap is set, page reclaim knows this mm_struct has been
774 * used since the last time it cleared the bitmap. So it might be worth
775 * walking the page tables of this mm_struct to clear the accessed bit.
776 */
777 WRITE_ONCE(mm->lru_gen.bitmap, -1);
778 }
779
780 #else /* !CONFIG_LRU_GEN */
781
lru_gen_add_mm(struct mm_struct * mm)782 static inline void lru_gen_add_mm(struct mm_struct *mm)
783 {
784 }
785
lru_gen_del_mm(struct mm_struct * mm)786 static inline void lru_gen_del_mm(struct mm_struct *mm)
787 {
788 }
789
790 #ifdef CONFIG_MEMCG
lru_gen_migrate_mm(struct mm_struct * mm)791 static inline void lru_gen_migrate_mm(struct mm_struct *mm)
792 {
793 }
794 #endif
795
lru_gen_init_mm(struct mm_struct * mm)796 static inline void lru_gen_init_mm(struct mm_struct *mm)
797 {
798 }
799
lru_gen_use_mm(struct mm_struct * mm)800 static inline void lru_gen_use_mm(struct mm_struct *mm)
801 {
802 }
803
804 #endif /* CONFIG_LRU_GEN */
805
806 struct vma_iterator {
807 struct ma_state mas;
808 };
809
810 #define VMA_ITERATOR(name, __mm, __addr) \
811 struct vma_iterator name = { \
812 .mas = { \
813 .tree = &(__mm)->mm_mt, \
814 .index = __addr, \
815 .node = MAS_START, \
816 }, \
817 }
818
vma_iter_init(struct vma_iterator * vmi,struct mm_struct * mm,unsigned long addr)819 static inline void vma_iter_init(struct vma_iterator *vmi,
820 struct mm_struct *mm, unsigned long addr)
821 {
822 vmi->mas.tree = &mm->mm_mt;
823 vmi->mas.index = addr;
824 vmi->mas.node = MAS_START;
825 }
826
827 struct mmu_gather;
828 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
829 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
830 extern void tlb_finish_mmu(struct mmu_gather *tlb);
831
832 struct vm_fault;
833
834 /**
835 * typedef vm_fault_t - Return type for page fault handlers.
836 *
837 * Page fault handlers return a bitmask of %VM_FAULT values.
838 */
839 typedef __bitwise unsigned int vm_fault_t;
840
841 /**
842 * enum vm_fault_reason - Page fault handlers return a bitmask of
843 * these values to tell the core VM what happened when handling the
844 * fault. Used to decide whether a process gets delivered SIGBUS or
845 * just gets major/minor fault counters bumped up.
846 *
847 * @VM_FAULT_OOM: Out Of Memory
848 * @VM_FAULT_SIGBUS: Bad access
849 * @VM_FAULT_MAJOR: Page read from storage
850 * @VM_FAULT_WRITE: Special case for get_user_pages
851 * @VM_FAULT_HWPOISON: Hit poisoned small page
852 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
853 * in upper bits
854 * @VM_FAULT_SIGSEGV: segmentation fault
855 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
856 * @VM_FAULT_LOCKED: ->fault locked the returned page
857 * @VM_FAULT_RETRY: ->fault blocked, must retry
858 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
859 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
860 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
861 * fsync() to complete (for synchronous page faults
862 * in DAX)
863 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released
864 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
865 *
866 */
867 enum vm_fault_reason {
868 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
869 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
870 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
871 VM_FAULT_WRITE = (__force vm_fault_t)0x000008,
872 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
873 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
874 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
875 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
876 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
877 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
878 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
879 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
880 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
881 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000,
882 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
883 };
884
885 /* Encode hstate index for a hwpoisoned large page */
886 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
887 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
888
889 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
890 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
891 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
892
893 #define VM_FAULT_RESULT_TRACE \
894 { VM_FAULT_OOM, "OOM" }, \
895 { VM_FAULT_SIGBUS, "SIGBUS" }, \
896 { VM_FAULT_MAJOR, "MAJOR" }, \
897 { VM_FAULT_WRITE, "WRITE" }, \
898 { VM_FAULT_HWPOISON, "HWPOISON" }, \
899 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
900 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
901 { VM_FAULT_NOPAGE, "NOPAGE" }, \
902 { VM_FAULT_LOCKED, "LOCKED" }, \
903 { VM_FAULT_RETRY, "RETRY" }, \
904 { VM_FAULT_FALLBACK, "FALLBACK" }, \
905 { VM_FAULT_DONE_COW, "DONE_COW" }, \
906 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
907
908 struct vm_special_mapping {
909 const char *name; /* The name, e.g. "[vdso]". */
910
911 /*
912 * If .fault is not provided, this points to a
913 * NULL-terminated array of pages that back the special mapping.
914 *
915 * This must not be NULL unless .fault is provided.
916 */
917 struct page **pages;
918
919 /*
920 * If non-NULL, then this is called to resolve page faults
921 * on the special mapping. If used, .pages is not checked.
922 */
923 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
924 struct vm_area_struct *vma,
925 struct vm_fault *vmf);
926
927 int (*mremap)(const struct vm_special_mapping *sm,
928 struct vm_area_struct *new_vma);
929 };
930
931 enum tlb_flush_reason {
932 TLB_FLUSH_ON_TASK_SWITCH,
933 TLB_REMOTE_SHOOTDOWN,
934 TLB_LOCAL_SHOOTDOWN,
935 TLB_LOCAL_MM_SHOOTDOWN,
936 TLB_REMOTE_SEND_IPI,
937 NR_TLB_FLUSH_REASONS,
938 };
939
940 /*
941 * A swap entry has to fit into a "unsigned long", as the entry is hidden
942 * in the "index" field of the swapper address space.
943 */
944 typedef struct {
945 unsigned long val;
946 } swp_entry_t;
947
948 /**
949 * enum fault_flag - Fault flag definitions.
950 * @FAULT_FLAG_WRITE: Fault was a write fault.
951 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
952 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
953 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
954 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
955 * @FAULT_FLAG_TRIED: The fault has been tried once.
956 * @FAULT_FLAG_USER: The fault originated in userspace.
957 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
958 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
959 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
960 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to unshare (and mark
961 * exclusive) a possibly shared anonymous page that is
962 * mapped R/O.
963 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
964 * We should only access orig_pte if this flag set.
965 *
966 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
967 * whether we would allow page faults to retry by specifying these two
968 * fault flags correctly. Currently there can be three legal combinations:
969 *
970 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and
971 * this is the first try
972 *
973 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and
974 * we've already tried at least once
975 *
976 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
977 *
978 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
979 * be used. Note that page faults can be allowed to retry for multiple times,
980 * in which case we'll have an initial fault with flags (a) then later on
981 * continuous faults with flags (b). We should always try to detect pending
982 * signals before a retry to make sure the continuous page faults can still be
983 * interrupted if necessary.
984 *
985 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
986 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
987 * no existing R/O-mapped anonymous page is encountered.
988 */
989 enum fault_flag {
990 FAULT_FLAG_WRITE = 1 << 0,
991 FAULT_FLAG_MKWRITE = 1 << 1,
992 FAULT_FLAG_ALLOW_RETRY = 1 << 2,
993 FAULT_FLAG_RETRY_NOWAIT = 1 << 3,
994 FAULT_FLAG_KILLABLE = 1 << 4,
995 FAULT_FLAG_TRIED = 1 << 5,
996 FAULT_FLAG_USER = 1 << 6,
997 FAULT_FLAG_REMOTE = 1 << 7,
998 FAULT_FLAG_INSTRUCTION = 1 << 8,
999 FAULT_FLAG_INTERRUPTIBLE = 1 << 9,
1000 FAULT_FLAG_UNSHARE = 1 << 10,
1001 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11,
1002 };
1003
1004 typedef unsigned int __bitwise zap_flags_t;
1005
1006 #endif /* _LINUX_MM_TYPES_H */
1007