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