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/rwsem.h>
13 #include <linux/completion.h>
14 #include <linux/cpumask.h>
15 #include <linux/uprobes.h>
16 #include <linux/page-flags-layout.h>
17 #include <linux/workqueue.h>
18 #include <linux/seqlock.h>
19
20 #include <asm/mmu.h>
21
22 #ifndef AT_VECTOR_SIZE_ARCH
23 #define AT_VECTOR_SIZE_ARCH 0
24 #endif
25 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
26
27 #define INIT_PASID 0
28
29 struct address_space;
30 struct mem_cgroup;
31
32 /*
33 * Each physical page in the system has a struct page associated with
34 * it to keep track of whatever it is we are using the page for at the
35 * moment. Note that we have no way to track which tasks are using
36 * a page, though if it is a pagecache page, rmap structures can tell us
37 * who is mapping it.
38 *
39 * If you allocate the page using alloc_pages(), you can use some of the
40 * space in struct page for your own purposes. The five words in the main
41 * union are available, except for bit 0 of the first word which must be
42 * kept clear. Many users use this word to store a pointer to an object
43 * which is guaranteed to be aligned. If you use the same storage as
44 * page->mapping, you must restore it to NULL before freeing the page.
45 *
46 * If your page will not be mapped to userspace, you can also use the four
47 * bytes in the mapcount union, but you must call page_mapcount_reset()
48 * before freeing it.
49 *
50 * If you want to use the refcount field, it must be used in such a way
51 * that other CPUs temporarily incrementing and then decrementing the
52 * refcount does not cause problems. On receiving the page from
53 * alloc_pages(), the refcount will be positive.
54 *
55 * If you allocate pages of order > 0, you can use some of the fields
56 * in each subpage, but you may need to restore some of their values
57 * afterwards.
58 *
59 * SLUB uses cmpxchg_double() to atomically update its freelist and
60 * counters. That requires that freelist & counters be adjacent and
61 * double-word aligned. We align all struct pages to double-word
62 * boundaries, and ensure that 'freelist' is aligned within the
63 * struct.
64 */
65 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
66 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long))
67 #else
68 #define _struct_page_alignment
69 #endif
70
71 struct page {
72 unsigned long flags; /* Atomic flags, some possibly
73 * updated asynchronously */
74 /*
75 * Five words (20/40 bytes) are available in this union.
76 * WARNING: bit 0 of the first word is used for PageTail(). That
77 * means the other users of this union MUST NOT use the bit to
78 * avoid collision and false-positive PageTail().
79 */
80 union {
81 struct { /* Page cache and anonymous pages */
82 /**
83 * @lru: Pageout list, eg. active_list protected by
84 * pgdat->lru_lock. Sometimes used as a generic list
85 * by the page owner.
86 */
87 struct list_head lru;
88 /* See page-flags.h for PAGE_MAPPING_FLAGS */
89 struct address_space *mapping;
90 pgoff_t index; /* Our offset within mapping. */
91 /**
92 * @private: Mapping-private opaque data.
93 * Usually used for buffer_heads if PagePrivate.
94 * Used for swp_entry_t if PageSwapCache.
95 * Indicates order in the buddy system if PageBuddy.
96 */
97 unsigned long private;
98 };
99 struct { /* page_pool used by netstack */
100 /**
101 * @dma_addr: might require a 64-bit value on
102 * 32-bit architectures.
103 */
104 unsigned long dma_addr[2];
105 };
106 struct { /* slab, slob and slub */
107 union {
108 struct list_head slab_list;
109 struct { /* Partial pages */
110 struct page *next;
111 #ifdef CONFIG_64BIT
112 int pages; /* Nr of pages left */
113 int pobjects; /* Approximate count */
114 #else
115 short int pages;
116 short int pobjects;
117 #endif
118 };
119 };
120 struct kmem_cache *slab_cache; /* not slob */
121 /* Double-word boundary */
122 void *freelist; /* first free object */
123 union {
124 void *s_mem; /* slab: first object */
125 unsigned long counters; /* SLUB */
126 struct { /* SLUB */
127 unsigned inuse:16;
128 unsigned objects:15;
129 unsigned frozen:1;
130 };
131 };
132 };
133 struct { /* Tail pages of compound page */
134 unsigned long compound_head; /* Bit zero is set */
135
136 /* First tail page only */
137 unsigned char compound_dtor;
138 unsigned char compound_order;
139 atomic_t compound_mapcount;
140 unsigned int compound_nr; /* 1 << compound_order */
141 };
142 struct { /* Second tail page of compound page */
143 unsigned long _compound_pad_1; /* compound_head */
144 atomic_t hpage_pinned_refcount;
145 /* For both global and memcg */
146 struct list_head deferred_list;
147 };
148 struct { /* Page table pages */
149 unsigned long _pt_pad_1; /* compound_head */
150 pgtable_t pmd_huge_pte; /* protected by page->ptl */
151 unsigned long _pt_pad_2; /* mapping */
152 union {
153 struct mm_struct *pt_mm; /* x86 pgds only */
154 atomic_t pt_frag_refcount; /* powerpc */
155 };
156 #if ALLOC_SPLIT_PTLOCKS
157 spinlock_t *ptl;
158 #else
159 spinlock_t ptl;
160 #endif
161 };
162 struct { /* ZONE_DEVICE pages */
163 /** @pgmap: Points to the hosting device page map. */
164 struct dev_pagemap *pgmap;
165 void *zone_device_data;
166 /*
167 * ZONE_DEVICE private pages are counted as being
168 * mapped so the next 3 words hold the mapping, index,
169 * and private fields from the source anonymous or
170 * page cache page while the page is migrated to device
171 * private memory.
172 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
173 * use the mapping, index, and private fields when
174 * pmem backed DAX files are mapped.
175 */
176 };
177
178 /** @rcu_head: You can use this to free a page by RCU. */
179 struct rcu_head rcu_head;
180 };
181
182 union { /* This union is 4 bytes in size. */
183 /*
184 * If the page can be mapped to userspace, encodes the number
185 * of times this page is referenced by a page table.
186 */
187 atomic_t _mapcount;
188
189 /*
190 * If the page is neither PageSlab nor mappable to userspace,
191 * the value stored here may help determine what this page
192 * is used for. See page-flags.h for a list of page types
193 * which are currently stored here.
194 */
195 unsigned int page_type;
196
197 unsigned int active; /* SLAB */
198 int units; /* SLOB */
199 };
200
201 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
202 atomic_t _refcount;
203
204 #ifdef CONFIG_MEMCG
205 union {
206 struct mem_cgroup *mem_cgroup;
207 struct obj_cgroup **obj_cgroups;
208 };
209 #endif
210
211 /*
212 * On machines where all RAM is mapped into kernel address space,
213 * we can simply calculate the virtual address. On machines with
214 * highmem some memory is mapped into kernel virtual memory
215 * dynamically, so we need a place to store that address.
216 * Note that this field could be 16 bits on x86 ... ;)
217 *
218 * Architectures with slow multiplication can define
219 * WANT_PAGE_VIRTUAL in asm/page.h
220 */
221 #if defined(WANT_PAGE_VIRTUAL)
222 void *virtual; /* Kernel virtual address (NULL if
223 not kmapped, ie. highmem) */
224 #endif /* WANT_PAGE_VIRTUAL */
225
226 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
227 int _last_cpupid;
228 #endif
229 } _struct_page_alignment;
230
compound_mapcount_ptr(struct page * page)231 static inline atomic_t *compound_mapcount_ptr(struct page *page)
232 {
233 return &page[1].compound_mapcount;
234 }
235
compound_pincount_ptr(struct page * page)236 static inline atomic_t *compound_pincount_ptr(struct page *page)
237 {
238 return &page[2].hpage_pinned_refcount;
239 }
240
241 /*
242 * Used for sizing the vmemmap region on some architectures
243 */
244 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
245
246 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
247 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
248
249 #define page_private(page) ((page)->private)
250
set_page_private(struct page * page,unsigned long private)251 static inline void set_page_private(struct page *page, unsigned long private)
252 {
253 page->private = private;
254 }
255
256 struct page_frag_cache {
257 void * va;
258 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
259 __u16 offset;
260 __u16 size;
261 #else
262 __u32 offset;
263 #endif
264 /* we maintain a pagecount bias, so that we dont dirty cache line
265 * containing page->_refcount every time we allocate a fragment.
266 */
267 unsigned int pagecnt_bias;
268 bool pfmemalloc;
269 };
270
271 typedef unsigned long vm_flags_t;
272
273 /*
274 * A region containing a mapping of a non-memory backed file under NOMMU
275 * conditions. These are held in a global tree and are pinned by the VMAs that
276 * map parts of them.
277 */
278 struct vm_region {
279 struct rb_node vm_rb; /* link in global region tree */
280 vm_flags_t vm_flags; /* VMA vm_flags */
281 unsigned long vm_start; /* start address of region */
282 unsigned long vm_end; /* region initialised to here */
283 unsigned long vm_top; /* region allocated to here */
284 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
285 struct file *vm_file; /* the backing file or NULL */
286
287 int vm_usage; /* region usage count (access under nommu_region_sem) */
288 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
289 * this region */
290 };
291
292 #ifdef CONFIG_USERFAULTFD
293 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
294 struct vm_userfaultfd_ctx {
295 struct userfaultfd_ctx *ctx;
296 };
297 #else /* CONFIG_USERFAULTFD */
298 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
299 struct vm_userfaultfd_ctx {};
300 #endif /* CONFIG_USERFAULTFD */
301
302 struct anon_vma_name {
303 struct kref kref;
304 /* The name needs to be at the end because it is dynamically sized. */
305 char name[];
306 };
307
308 /*
309 * This struct describes a virtual memory area. There is one of these
310 * per VM-area/task. A VM area is any part of the process virtual memory
311 * space that has a special rule for the page-fault handlers (ie a shared
312 * library, the executable area etc).
313 */
314 struct vm_area_struct {
315 /* The first cache line has the info for VMA tree walking. */
316
317 unsigned long vm_start; /* Our start address within vm_mm. */
318 unsigned long vm_end; /* The first byte after our end address
319 within vm_mm. */
320
321 /* linked list of VM areas per task, sorted by address */
322 struct vm_area_struct *vm_next, *vm_prev;
323
324 struct rb_node vm_rb;
325
326 /*
327 * Largest free memory gap in bytes to the left of this VMA.
328 * Either between this VMA and vma->vm_prev, or between one of the
329 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
330 * get_unmapped_area find a free area of the right size.
331 */
332 unsigned long rb_subtree_gap;
333
334 /* Second cache line starts here. */
335
336 struct mm_struct *vm_mm; /* The address space we belong to. */
337
338 /*
339 * Access permissions of this VMA.
340 * See vmf_insert_mixed_prot() for discussion.
341 */
342 pgprot_t vm_page_prot;
343 unsigned long vm_flags; /* Flags, see mm.h. */
344
345 /*
346 * For areas with an address space and backing store,
347 * linkage into the address_space->i_mmap interval tree.
348 *
349 * For private anonymous mappings, a pointer to a null terminated string
350 * containing the name given to the vma, or NULL if unnamed.
351 */
352
353 union {
354 struct {
355 struct rb_node rb;
356 unsigned long rb_subtree_last;
357 } shared;
358 /* Serialized by mmap_sem. */
359 struct anon_vma_name *anon_name;
360 };
361
362 /*
363 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
364 * list, after a COW of one of the file pages. A MAP_SHARED vma
365 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
366 * or brk vma (with NULL file) can only be in an anon_vma list.
367 */
368 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
369 * page_table_lock */
370 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
371
372 /* Function pointers to deal with this struct. */
373 const struct vm_operations_struct *vm_ops;
374
375 /* Information about our backing store: */
376 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
377 units */
378 struct file * vm_file; /* File we map to (can be NULL). */
379 void * vm_private_data; /* was vm_pte (shared mem) */
380
381 #ifdef CONFIG_SWAP
382 atomic_long_t swap_readahead_info;
383 #endif
384 #ifndef CONFIG_MMU
385 struct vm_region *vm_region; /* NOMMU mapping region */
386 #endif
387 #ifdef CONFIG_NUMA
388 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
389 #endif
390 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
391 } __randomize_layout;
392
393 struct core_thread {
394 struct task_struct *task;
395 struct core_thread *next;
396 };
397
398 struct core_state {
399 atomic_t nr_threads;
400 struct core_thread dumper;
401 struct completion startup;
402 };
403
404 struct kioctx_table;
405 struct mm_struct {
406 struct {
407 struct vm_area_struct *mmap; /* list of VMAs */
408 struct rb_root mm_rb;
409 u64 vmacache_seqnum; /* per-thread vmacache */
410 #ifdef CONFIG_MMU
411 unsigned long (*get_unmapped_area) (struct file *filp,
412 unsigned long addr, unsigned long len,
413 unsigned long pgoff, unsigned long flags);
414 #endif
415 unsigned long mmap_base; /* base of mmap area */
416 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
417 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
418 /* Base adresses for compatible mmap() */
419 unsigned long mmap_compat_base;
420 unsigned long mmap_compat_legacy_base;
421 #endif
422 unsigned long task_size; /* size of task vm space */
423 unsigned long highest_vm_end; /* highest vma end address */
424 pgd_t * pgd;
425
426 #ifdef CONFIG_MEMBARRIER
427 /**
428 * @membarrier_state: Flags controlling membarrier behavior.
429 *
430 * This field is close to @pgd to hopefully fit in the same
431 * cache-line, which needs to be touched by switch_mm().
432 */
433 atomic_t membarrier_state;
434 #endif
435
436 /**
437 * @mm_users: The number of users including userspace.
438 *
439 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
440 * drops to 0 (i.e. when the task exits and there are no other
441 * temporary reference holders), we also release a reference on
442 * @mm_count (which may then free the &struct mm_struct if
443 * @mm_count also drops to 0).
444 */
445 atomic_t mm_users;
446
447 /**
448 * @mm_count: The number of references to &struct mm_struct
449 * (@mm_users count as 1).
450 *
451 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
452 * &struct mm_struct is freed.
453 */
454 atomic_t mm_count;
455
456 /**
457 * @has_pinned: Whether this mm has pinned any pages. This can
458 * be either replaced in the future by @pinned_vm when it
459 * becomes stable, or grow into a counter on its own. We're
460 * aggresive on this bit now - even if the pinned pages were
461 * unpinned later on, we'll still keep this bit set for the
462 * lifecycle of this mm just for simplicity.
463 */
464 atomic_t has_pinned;
465
466 #ifdef CONFIG_MMU
467 atomic_long_t pgtables_bytes; /* PTE page table pages */
468 #endif
469 int map_count; /* number of VMAs */
470
471 spinlock_t page_table_lock; /* Protects page tables and some
472 * counters
473 */
474 /*
475 * With some kernel config, the current mmap_lock's offset
476 * inside 'mm_struct' is at 0x120, which is very optimal, as
477 * its two hot fields 'count' and 'owner' sit in 2 different
478 * cachelines, and when mmap_lock is highly contended, both
479 * of the 2 fields will be accessed frequently, current layout
480 * will help to reduce cache bouncing.
481 *
482 * So please be careful with adding new fields before
483 * mmap_lock, which can easily push the 2 fields into one
484 * cacheline.
485 */
486 struct rw_semaphore mmap_lock;
487
488 struct list_head mmlist; /* List of maybe swapped mm's. These
489 * are globally strung together off
490 * init_mm.mmlist, and are protected
491 * by mmlist_lock
492 */
493
494
495 unsigned long hiwater_rss; /* High-watermark of RSS usage */
496 unsigned long hiwater_vm; /* High-water virtual memory usage */
497
498 unsigned long total_vm; /* Total pages mapped */
499 unsigned long locked_vm; /* Pages that have PG_mlocked set */
500 atomic64_t pinned_vm; /* Refcount permanently increased */
501 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
502 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
503 unsigned long stack_vm; /* VM_STACK */
504 unsigned long def_flags;
505
506 /**
507 * @write_protect_seq: Locked when any thread is write
508 * protecting pages mapped by this mm to enforce a later COW,
509 * for instance during page table copying for fork().
510 */
511 seqcount_t write_protect_seq;
512
513 spinlock_t arg_lock; /* protect the below fields */
514
515 unsigned long start_code, end_code, start_data, end_data;
516 unsigned long start_brk, brk, start_stack;
517 unsigned long arg_start, arg_end, env_start, env_end;
518
519 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
520
521 /*
522 * Special counters, in some configurations protected by the
523 * page_table_lock, in other configurations by being atomic.
524 */
525 struct mm_rss_stat rss_stat;
526
527 struct linux_binfmt *binfmt;
528
529 /* Architecture-specific MM context */
530 mm_context_t context;
531
532 unsigned long flags; /* Must use atomic bitops to access */
533
534 struct core_state *core_state; /* coredumping support */
535
536 #ifdef CONFIG_AIO
537 spinlock_t ioctx_lock;
538 struct kioctx_table __rcu *ioctx_table;
539 #endif
540 #ifdef CONFIG_MEMCG
541 /*
542 * "owner" points to a task that is regarded as the canonical
543 * user/owner of this mm. All of the following must be true in
544 * order for it to be changed:
545 *
546 * current == mm->owner
547 * current->mm != mm
548 * new_owner->mm == mm
549 * new_owner->alloc_lock is held
550 */
551 struct task_struct __rcu *owner;
552 #endif
553 struct user_namespace *user_ns;
554
555 /* store ref to file /proc/<pid>/exe symlink points to */
556 struct file __rcu *exe_file;
557 #ifdef CONFIG_MMU_NOTIFIER
558 struct mmu_notifier_subscriptions *notifier_subscriptions;
559 #endif
560 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
561 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
562 #endif
563 #ifdef CONFIG_NUMA_BALANCING
564 /*
565 * numa_next_scan is the next time that the PTEs will be marked
566 * pte_numa. NUMA hinting faults will gather statistics and
567 * migrate pages to new nodes if necessary.
568 */
569 unsigned long numa_next_scan;
570
571 /* Restart point for scanning and setting pte_numa */
572 unsigned long numa_scan_offset;
573
574 /* numa_scan_seq prevents two threads setting pte_numa */
575 int numa_scan_seq;
576 #endif
577 /*
578 * An operation with batched TLB flushing is going on. Anything
579 * that can move process memory needs to flush the TLB when
580 * moving a PROT_NONE or PROT_NUMA mapped page.
581 */
582 atomic_t tlb_flush_pending;
583 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
584 /* See flush_tlb_batched_pending() */
585 bool tlb_flush_batched;
586 #endif
587 struct uprobes_state uprobes_state;
588 #ifdef CONFIG_HUGETLB_PAGE
589 atomic_long_t hugetlb_usage;
590 #endif
591 struct work_struct async_put_work;
592
593 #ifdef CONFIG_IOMMU_SUPPORT
594 u32 pasid;
595 #endif
596 } __randomize_layout;
597
598 /*
599 * The mm_cpumask needs to be at the end of mm_struct, because it
600 * is dynamically sized based on nr_cpu_ids.
601 */
602 unsigned long cpu_bitmap[];
603 };
604
605 extern struct mm_struct init_mm;
606
607 /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)608 static inline void mm_init_cpumask(struct mm_struct *mm)
609 {
610 unsigned long cpu_bitmap = (unsigned long)mm;
611
612 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
613 cpumask_clear((struct cpumask *)cpu_bitmap);
614 }
615
616 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)617 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
618 {
619 return (struct cpumask *)&mm->cpu_bitmap;
620 }
621
622 struct mmu_gather;
623 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
624 unsigned long start, unsigned long end);
625 extern void tlb_finish_mmu(struct mmu_gather *tlb,
626 unsigned long start, unsigned long end);
627
init_tlb_flush_pending(struct mm_struct * mm)628 static inline void init_tlb_flush_pending(struct mm_struct *mm)
629 {
630 atomic_set(&mm->tlb_flush_pending, 0);
631 }
632
inc_tlb_flush_pending(struct mm_struct * mm)633 static inline void inc_tlb_flush_pending(struct mm_struct *mm)
634 {
635 atomic_inc(&mm->tlb_flush_pending);
636 /*
637 * The only time this value is relevant is when there are indeed pages
638 * to flush. And we'll only flush pages after changing them, which
639 * requires the PTL.
640 *
641 * So the ordering here is:
642 *
643 * atomic_inc(&mm->tlb_flush_pending);
644 * spin_lock(&ptl);
645 * ...
646 * set_pte_at();
647 * spin_unlock(&ptl);
648 *
649 * spin_lock(&ptl)
650 * mm_tlb_flush_pending();
651 * ....
652 * spin_unlock(&ptl);
653 *
654 * flush_tlb_range();
655 * atomic_dec(&mm->tlb_flush_pending);
656 *
657 * Where the increment if constrained by the PTL unlock, it thus
658 * ensures that the increment is visible if the PTE modification is
659 * visible. After all, if there is no PTE modification, nobody cares
660 * about TLB flushes either.
661 *
662 * This very much relies on users (mm_tlb_flush_pending() and
663 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
664 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
665 * locks (PPC) the unlock of one doesn't order against the lock of
666 * another PTL.
667 *
668 * The decrement is ordered by the flush_tlb_range(), such that
669 * mm_tlb_flush_pending() will not return false unless all flushes have
670 * completed.
671 */
672 }
673
dec_tlb_flush_pending(struct mm_struct * mm)674 static inline void dec_tlb_flush_pending(struct mm_struct *mm)
675 {
676 /*
677 * See inc_tlb_flush_pending().
678 *
679 * This cannot be smp_mb__before_atomic() because smp_mb() simply does
680 * not order against TLB invalidate completion, which is what we need.
681 *
682 * Therefore we must rely on tlb_flush_*() to guarantee order.
683 */
684 atomic_dec(&mm->tlb_flush_pending);
685 }
686
mm_tlb_flush_pending(struct mm_struct * mm)687 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
688 {
689 /*
690 * Must be called after having acquired the PTL; orders against that
691 * PTLs release and therefore ensures that if we observe the modified
692 * PTE we must also observe the increment from inc_tlb_flush_pending().
693 *
694 * That is, it only guarantees to return true if there is a flush
695 * pending for _this_ PTL.
696 */
697 return atomic_read(&mm->tlb_flush_pending);
698 }
699
mm_tlb_flush_nested(struct mm_struct * mm)700 static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
701 {
702 /*
703 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
704 * for which there is a TLB flush pending in order to guarantee
705 * we've seen both that PTE modification and the increment.
706 *
707 * (no requirement on actually still holding the PTL, that is irrelevant)
708 */
709 return atomic_read(&mm->tlb_flush_pending) > 1;
710 }
711
712 struct vm_fault;
713
714 /**
715 * typedef vm_fault_t - Return type for page fault handlers.
716 *
717 * Page fault handlers return a bitmask of %VM_FAULT values.
718 */
719 typedef __bitwise unsigned int vm_fault_t;
720
721 /**
722 * enum vm_fault_reason - Page fault handlers return a bitmask of
723 * these values to tell the core VM what happened when handling the
724 * fault. Used to decide whether a process gets delivered SIGBUS or
725 * just gets major/minor fault counters bumped up.
726 *
727 * @VM_FAULT_OOM: Out Of Memory
728 * @VM_FAULT_SIGBUS: Bad access
729 * @VM_FAULT_MAJOR: Page read from storage
730 * @VM_FAULT_WRITE: Special case for get_user_pages
731 * @VM_FAULT_HWPOISON: Hit poisoned small page
732 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
733 * in upper bits
734 * @VM_FAULT_SIGSEGV: segmentation fault
735 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
736 * @VM_FAULT_LOCKED: ->fault locked the returned page
737 * @VM_FAULT_RETRY: ->fault blocked, must retry
738 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
739 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
740 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
741 * fsync() to complete (for synchronous page faults
742 * in DAX)
743 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
744 *
745 */
746 enum vm_fault_reason {
747 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
748 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
749 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
750 VM_FAULT_WRITE = (__force vm_fault_t)0x000008,
751 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
752 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
753 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
754 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
755 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
756 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
757 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
758 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
759 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
760 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
761 };
762
763 /* Encode hstate index for a hwpoisoned large page */
764 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
765 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
766
767 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
768 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
769 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
770
771 #define VM_FAULT_RESULT_TRACE \
772 { VM_FAULT_OOM, "OOM" }, \
773 { VM_FAULT_SIGBUS, "SIGBUS" }, \
774 { VM_FAULT_MAJOR, "MAJOR" }, \
775 { VM_FAULT_WRITE, "WRITE" }, \
776 { VM_FAULT_HWPOISON, "HWPOISON" }, \
777 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
778 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
779 { VM_FAULT_NOPAGE, "NOPAGE" }, \
780 { VM_FAULT_LOCKED, "LOCKED" }, \
781 { VM_FAULT_RETRY, "RETRY" }, \
782 { VM_FAULT_FALLBACK, "FALLBACK" }, \
783 { VM_FAULT_DONE_COW, "DONE_COW" }, \
784 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
785
786 struct vm_special_mapping {
787 const char *name; /* The name, e.g. "[vdso]". */
788
789 /*
790 * If .fault is not provided, this points to a
791 * NULL-terminated array of pages that back the special mapping.
792 *
793 * This must not be NULL unless .fault is provided.
794 */
795 struct page **pages;
796
797 /*
798 * If non-NULL, then this is called to resolve page faults
799 * on the special mapping. If used, .pages is not checked.
800 */
801 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
802 struct vm_area_struct *vma,
803 struct vm_fault *vmf);
804
805 int (*mremap)(const struct vm_special_mapping *sm,
806 struct vm_area_struct *new_vma);
807 };
808
809 enum tlb_flush_reason {
810 TLB_FLUSH_ON_TASK_SWITCH,
811 TLB_REMOTE_SHOOTDOWN,
812 TLB_LOCAL_SHOOTDOWN,
813 TLB_LOCAL_MM_SHOOTDOWN,
814 TLB_REMOTE_SEND_IPI,
815 NR_TLB_FLUSH_REASONS,
816 };
817
818 /*
819 * A swap entry has to fit into a "unsigned long", as the entry is hidden
820 * in the "index" field of the swapper address space.
821 */
822 typedef struct {
823 unsigned long val;
824 } swp_entry_t;
825
826 #ifdef CONFIG_ANON_VMA_NAME
827 /*
828 * mmap_lock should be read-locked when calling vma_anon_name() and while using
829 * the returned pointer.
830 */
831 extern const char *vma_anon_name(struct vm_area_struct *vma);
832
833 /*
834 * mmap_lock should be read-locked for orig_vma->vm_mm.
835 * mmap_lock should be write-locked for new_vma->vm_mm or new_vma should be
836 * isolated.
837 */
838 extern void dup_vma_anon_name(struct vm_area_struct *orig_vma,
839 struct vm_area_struct *new_vma);
840
841 /*
842 * mmap_lock should be write-locked or vma should have been isolated under
843 * write-locked mmap_lock protection.
844 */
845 extern void free_vma_anon_name(struct vm_area_struct *vma);
846
847 /* mmap_lock should be read-locked */
is_same_vma_anon_name(struct vm_area_struct * vma,const char * name)848 static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
849 const char *name)
850 {
851 const char *vma_name = vma_anon_name(vma);
852
853 /* either both NULL, or pointers to same string */
854 if (vma_name == name)
855 return true;
856
857 return name && vma_name && !strcmp(name, vma_name);
858 }
859 #else /* CONFIG_ANON_VMA_NAME */
vma_anon_name(struct vm_area_struct * vma)860 static inline const char *vma_anon_name(struct vm_area_struct *vma)
861 {
862 return NULL;
863 }
dup_vma_anon_name(struct vm_area_struct * orig_vma,struct vm_area_struct * new_vma)864 static inline void dup_vma_anon_name(struct vm_area_struct *orig_vma,
865 struct vm_area_struct *new_vma) {}
free_vma_anon_name(struct vm_area_struct * vma)866 static inline void free_vma_anon_name(struct vm_area_struct *vma) {}
is_same_vma_anon_name(struct vm_area_struct * vma,const char * name)867 static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
868 const char *name)
869 {
870 return true;
871 }
872 #endif /* CONFIG_ANON_VMA_NAME */
873
874 #endif /* _LINUX_MM_TYPES_H */
875