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 /*
359 * Serialized by mmap_sem. Never use directly because it is
360 * valid only when vm_file is NULL. Use anon_vma_name instead.
361 */
362 struct anon_vma_name *anon_name;
363 };
364
365 /*
366 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
367 * list, after a COW of one of the file pages. A MAP_SHARED vma
368 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
369 * or brk vma (with NULL file) can only be in an anon_vma list.
370 */
371 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
372 * page_table_lock */
373 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
374
375 /* Function pointers to deal with this struct. */
376 const struct vm_operations_struct *vm_ops;
377
378 /* Information about our backing store: */
379 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
380 units */
381 struct file * vm_file; /* File we map to (can be NULL). */
382 void * vm_private_data; /* was vm_pte (shared mem) */
383
384 #ifdef CONFIG_SWAP
385 atomic_long_t swap_readahead_info;
386 #endif
387 #ifndef CONFIG_MMU
388 struct vm_region *vm_region; /* NOMMU mapping region */
389 #endif
390 #ifdef CONFIG_NUMA
391 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
392 #endif
393 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
394 } __randomize_layout;
395
396 struct core_thread {
397 struct task_struct *task;
398 struct core_thread *next;
399 };
400
401 struct core_state {
402 atomic_t nr_threads;
403 struct core_thread dumper;
404 struct completion startup;
405 };
406
407 struct kioctx_table;
408 struct mm_struct {
409 struct {
410 struct vm_area_struct *mmap; /* list of VMAs */
411 struct rb_root mm_rb;
412 u64 vmacache_seqnum; /* per-thread vmacache */
413 #ifdef CONFIG_MMU
414 unsigned long (*get_unmapped_area) (struct file *filp,
415 unsigned long addr, unsigned long len,
416 unsigned long pgoff, unsigned long flags);
417 #endif
418 unsigned long mmap_base; /* base of mmap area */
419 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
420 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
421 /* Base adresses for compatible mmap() */
422 unsigned long mmap_compat_base;
423 unsigned long mmap_compat_legacy_base;
424 #endif
425 unsigned long task_size; /* size of task vm space */
426 unsigned long highest_vm_end; /* highest vma end address */
427 pgd_t * pgd;
428 #ifdef CONFIG_MEM_PURGEABLE
429 void *uxpgd;
430 spinlock_t uxpgd_lock;
431 #endif
432
433 #ifdef CONFIG_MEMBARRIER
434 /**
435 * @membarrier_state: Flags controlling membarrier behavior.
436 *
437 * This field is close to @pgd to hopefully fit in the same
438 * cache-line, which needs to be touched by switch_mm().
439 */
440 atomic_t membarrier_state;
441 #endif
442
443 /**
444 * @mm_users: The number of users including userspace.
445 *
446 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
447 * drops to 0 (i.e. when the task exits and there are no other
448 * temporary reference holders), we also release a reference on
449 * @mm_count (which may then free the &struct mm_struct if
450 * @mm_count also drops to 0).
451 */
452 atomic_t mm_users;
453
454 /**
455 * @mm_count: The number of references to &struct mm_struct
456 * (@mm_users count as 1).
457 *
458 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
459 * &struct mm_struct is freed.
460 */
461 atomic_t mm_count;
462
463 /**
464 * @has_pinned: Whether this mm has pinned any pages. This can
465 * be either replaced in the future by @pinned_vm when it
466 * becomes stable, or grow into a counter on its own. We're
467 * aggresive on this bit now - even if the pinned pages were
468 * unpinned later on, we'll still keep this bit set for the
469 * lifecycle of this mm just for simplicity.
470 */
471 atomic_t has_pinned;
472
473 #ifdef CONFIG_MMU
474 atomic_long_t pgtables_bytes; /* PTE page table pages */
475 #endif
476 int map_count; /* number of VMAs */
477
478 spinlock_t page_table_lock; /* Protects page tables and some
479 * counters
480 */
481 /*
482 * With some kernel config, the current mmap_lock's offset
483 * inside 'mm_struct' is at 0x120, which is very optimal, as
484 * its two hot fields 'count' and 'owner' sit in 2 different
485 * cachelines, and when mmap_lock is highly contended, both
486 * of the 2 fields will be accessed frequently, current layout
487 * will help to reduce cache bouncing.
488 *
489 * So please be careful with adding new fields before
490 * mmap_lock, which can easily push the 2 fields into one
491 * cacheline.
492 */
493 struct rw_semaphore mmap_lock;
494
495 struct list_head mmlist; /* List of maybe swapped mm's. These
496 * are globally strung together off
497 * init_mm.mmlist, and are protected
498 * by mmlist_lock
499 */
500
501
502 unsigned long hiwater_rss; /* High-watermark of RSS usage */
503 unsigned long hiwater_vm; /* High-water virtual memory usage */
504 #ifdef CONFIG_RSS_THRESHOLD
505 unsigned long rss_threshold; /* A threshold monitor RSS */
506 #endif
507
508 unsigned long total_vm; /* Total pages mapped */
509 unsigned long locked_vm; /* Pages that have PG_mlocked set */
510 atomic64_t pinned_vm; /* Refcount permanently increased */
511 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
512 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
513 unsigned long stack_vm; /* VM_STACK */
514 unsigned long def_flags;
515
516 /**
517 * @write_protect_seq: Locked when any thread is write
518 * protecting pages mapped by this mm to enforce a later COW,
519 * for instance during page table copying for fork().
520 */
521 seqcount_t write_protect_seq;
522
523 spinlock_t arg_lock; /* protect the below fields */
524
525 unsigned long start_code, end_code, start_data, end_data;
526 unsigned long start_brk, brk, start_stack;
527 unsigned long arg_start, arg_end, env_start, env_end;
528
529 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
530
531 /*
532 * Special counters, in some configurations protected by the
533 * page_table_lock, in other configurations by being atomic.
534 */
535 struct mm_rss_stat rss_stat;
536
537 struct linux_binfmt *binfmt;
538
539 /* Architecture-specific MM context */
540 mm_context_t context;
541
542 unsigned long flags; /* Must use atomic bitops to access */
543
544 struct core_state *core_state; /* coredumping support */
545
546 #ifdef CONFIG_AIO
547 spinlock_t ioctx_lock;
548 struct kioctx_table __rcu *ioctx_table;
549 #endif
550 #ifdef CONFIG_MEMCG
551 /*
552 * "owner" points to a task that is regarded as the canonical
553 * user/owner of this mm. All of the following must be true in
554 * order for it to be changed:
555 *
556 * current == mm->owner
557 * current->mm != mm
558 * new_owner->mm == mm
559 * new_owner->alloc_lock is held
560 */
561 struct task_struct __rcu *owner;
562 #endif
563 struct user_namespace *user_ns;
564
565 /* store ref to file /proc/<pid>/exe symlink points to */
566 struct file __rcu *exe_file;
567 #ifdef CONFIG_MMU_NOTIFIER
568 struct mmu_notifier_subscriptions *notifier_subscriptions;
569 #endif
570 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
571 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
572 #endif
573 #ifdef CONFIG_NUMA_BALANCING
574 /*
575 * numa_next_scan is the next time that the PTEs will be marked
576 * pte_numa. NUMA hinting faults will gather statistics and
577 * migrate pages to new nodes if necessary.
578 */
579 unsigned long numa_next_scan;
580
581 /* Restart point for scanning and setting pte_numa */
582 unsigned long numa_scan_offset;
583
584 /* numa_scan_seq prevents two threads setting pte_numa */
585 int numa_scan_seq;
586 #endif
587 /*
588 * An operation with batched TLB flushing is going on. Anything
589 * that can move process memory needs to flush the TLB when
590 * moving a PROT_NONE or PROT_NUMA mapped page.
591 */
592 atomic_t tlb_flush_pending;
593 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
594 /* See flush_tlb_batched_pending() */
595 bool tlb_flush_batched;
596 #endif
597 struct uprobes_state uprobes_state;
598 #ifdef CONFIG_HUGETLB_PAGE
599 atomic_long_t hugetlb_usage;
600 #endif
601 struct work_struct async_put_work;
602
603 #ifdef CONFIG_IOMMU_SUPPORT
604 u32 pasid;
605 #endif
606 } __randomize_layout;
607
608 /*
609 * The mm_cpumask needs to be at the end of mm_struct, because it
610 * is dynamically sized based on nr_cpu_ids.
611 */
612 unsigned long cpu_bitmap[];
613 };
614
615 extern struct mm_struct init_mm;
616
617 /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)618 static inline void mm_init_cpumask(struct mm_struct *mm)
619 {
620 unsigned long cpu_bitmap = (unsigned long)mm;
621
622 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
623 cpumask_clear((struct cpumask *)cpu_bitmap);
624 }
625
626 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)627 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
628 {
629 return (struct cpumask *)&mm->cpu_bitmap;
630 }
631
632 struct mmu_gather;
633 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
634 unsigned long start, unsigned long end);
635 extern void tlb_finish_mmu(struct mmu_gather *tlb,
636 unsigned long start, unsigned long end);
637
init_tlb_flush_pending(struct mm_struct * mm)638 static inline void init_tlb_flush_pending(struct mm_struct *mm)
639 {
640 atomic_set(&mm->tlb_flush_pending, 0);
641 }
642
inc_tlb_flush_pending(struct mm_struct * mm)643 static inline void inc_tlb_flush_pending(struct mm_struct *mm)
644 {
645 atomic_inc(&mm->tlb_flush_pending);
646 /*
647 * The only time this value is relevant is when there are indeed pages
648 * to flush. And we'll only flush pages after changing them, which
649 * requires the PTL.
650 *
651 * So the ordering here is:
652 *
653 * atomic_inc(&mm->tlb_flush_pending);
654 * spin_lock(&ptl);
655 * ...
656 * set_pte_at();
657 * spin_unlock(&ptl);
658 *
659 * spin_lock(&ptl)
660 * mm_tlb_flush_pending();
661 * ....
662 * spin_unlock(&ptl);
663 *
664 * flush_tlb_range();
665 * atomic_dec(&mm->tlb_flush_pending);
666 *
667 * Where the increment if constrained by the PTL unlock, it thus
668 * ensures that the increment is visible if the PTE modification is
669 * visible. After all, if there is no PTE modification, nobody cares
670 * about TLB flushes either.
671 *
672 * This very much relies on users (mm_tlb_flush_pending() and
673 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
674 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
675 * locks (PPC) the unlock of one doesn't order against the lock of
676 * another PTL.
677 *
678 * The decrement is ordered by the flush_tlb_range(), such that
679 * mm_tlb_flush_pending() will not return false unless all flushes have
680 * completed.
681 */
682 }
683
dec_tlb_flush_pending(struct mm_struct * mm)684 static inline void dec_tlb_flush_pending(struct mm_struct *mm)
685 {
686 /*
687 * See inc_tlb_flush_pending().
688 *
689 * This cannot be smp_mb__before_atomic() because smp_mb() simply does
690 * not order against TLB invalidate completion, which is what we need.
691 *
692 * Therefore we must rely on tlb_flush_*() to guarantee order.
693 */
694 atomic_dec(&mm->tlb_flush_pending);
695 }
696
mm_tlb_flush_pending(struct mm_struct * mm)697 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
698 {
699 /*
700 * Must be called after having acquired the PTL; orders against that
701 * PTLs release and therefore ensures that if we observe the modified
702 * PTE we must also observe the increment from inc_tlb_flush_pending().
703 *
704 * That is, it only guarantees to return true if there is a flush
705 * pending for _this_ PTL.
706 */
707 return atomic_read(&mm->tlb_flush_pending);
708 }
709
mm_tlb_flush_nested(struct mm_struct * mm)710 static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
711 {
712 /*
713 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
714 * for which there is a TLB flush pending in order to guarantee
715 * we've seen both that PTE modification and the increment.
716 *
717 * (no requirement on actually still holding the PTL, that is irrelevant)
718 */
719 return atomic_read(&mm->tlb_flush_pending) > 1;
720 }
721
722 struct vm_fault;
723
724 /**
725 * typedef vm_fault_t - Return type for page fault handlers.
726 *
727 * Page fault handlers return a bitmask of %VM_FAULT values.
728 */
729 typedef __bitwise unsigned int vm_fault_t;
730
731 /**
732 * enum vm_fault_reason - Page fault handlers return a bitmask of
733 * these values to tell the core VM what happened when handling the
734 * fault. Used to decide whether a process gets delivered SIGBUS or
735 * just gets major/minor fault counters bumped up.
736 *
737 * @VM_FAULT_OOM: Out Of Memory
738 * @VM_FAULT_SIGBUS: Bad access
739 * @VM_FAULT_MAJOR: Page read from storage
740 * @VM_FAULT_WRITE: Special case for get_user_pages
741 * @VM_FAULT_HWPOISON: Hit poisoned small page
742 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
743 * in upper bits
744 * @VM_FAULT_SIGSEGV: segmentation fault
745 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
746 * @VM_FAULT_LOCKED: ->fault locked the returned page
747 * @VM_FAULT_RETRY: ->fault blocked, must retry
748 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
749 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
750 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
751 * fsync() to complete (for synchronous page faults
752 * in DAX)
753 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
754 *
755 */
756 enum vm_fault_reason {
757 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
758 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
759 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
760 VM_FAULT_WRITE = (__force vm_fault_t)0x000008,
761 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
762 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
763 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
764 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
765 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
766 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
767 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
768 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
769 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
770 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
771 };
772
773 /* Encode hstate index for a hwpoisoned large page */
774 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
775 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
776
777 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
778 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
779 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
780
781 #define VM_FAULT_RESULT_TRACE \
782 { VM_FAULT_OOM, "OOM" }, \
783 { VM_FAULT_SIGBUS, "SIGBUS" }, \
784 { VM_FAULT_MAJOR, "MAJOR" }, \
785 { VM_FAULT_WRITE, "WRITE" }, \
786 { VM_FAULT_HWPOISON, "HWPOISON" }, \
787 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
788 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
789 { VM_FAULT_NOPAGE, "NOPAGE" }, \
790 { VM_FAULT_LOCKED, "LOCKED" }, \
791 { VM_FAULT_RETRY, "RETRY" }, \
792 { VM_FAULT_FALLBACK, "FALLBACK" }, \
793 { VM_FAULT_DONE_COW, "DONE_COW" }, \
794 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
795
796 struct vm_special_mapping {
797 const char *name; /* The name, e.g. "[vdso]". */
798
799 /*
800 * If .fault is not provided, this points to a
801 * NULL-terminated array of pages that back the special mapping.
802 *
803 * This must not be NULL unless .fault is provided.
804 */
805 struct page **pages;
806
807 /*
808 * If non-NULL, then this is called to resolve page faults
809 * on the special mapping. If used, .pages is not checked.
810 */
811 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
812 struct vm_area_struct *vma,
813 struct vm_fault *vmf);
814
815 int (*mremap)(const struct vm_special_mapping *sm,
816 struct vm_area_struct *new_vma);
817 };
818
819 enum tlb_flush_reason {
820 TLB_FLUSH_ON_TASK_SWITCH,
821 TLB_REMOTE_SHOOTDOWN,
822 TLB_LOCAL_SHOOTDOWN,
823 TLB_LOCAL_MM_SHOOTDOWN,
824 TLB_REMOTE_SEND_IPI,
825 NR_TLB_FLUSH_REASONS,
826 };
827
828 /*
829 * A swap entry has to fit into a "unsigned long", as the entry is hidden
830 * in the "index" field of the swapper address space.
831 */
832 typedef struct {
833 unsigned long val;
834 } swp_entry_t;
835
836 #endif /* _LINUX_MM_TYPES_H */
837