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 #include <linux/android_kabi.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 __rcu *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 /*
303 * This struct describes a virtual memory area. There is one of these
304 * per VM-area/task. A VM area is any part of the process virtual memory
305 * space that has a special rule for the page-fault handlers (ie a shared
306 * library, the executable area etc).
307 */
308 struct vm_area_struct {
309 /* The first cache line has the info for VMA tree walking. */
310
311 unsigned long vm_start; /* Our start address within vm_mm. */
312 unsigned long vm_end; /* The first byte after our end address
313 within vm_mm. */
314
315 /* linked list of VM areas per task, sorted by address */
316 struct vm_area_struct *vm_next, *vm_prev;
317
318 struct rb_node vm_rb;
319
320 /*
321 * Largest free memory gap in bytes to the left of this VMA.
322 * Either between this VMA and vma->vm_prev, or between one of the
323 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
324 * get_unmapped_area find a free area of the right size.
325 */
326 unsigned long rb_subtree_gap;
327
328 /* Second cache line starts here. */
329
330 struct mm_struct *vm_mm; /* The address space we belong to. */
331
332 /*
333 * Access permissions of this VMA.
334 * See vmf_insert_mixed_prot() for discussion.
335 */
336 pgprot_t vm_page_prot;
337 unsigned long vm_flags; /* Flags, see mm.h. */
338
339 /*
340 * For areas with an address space and backing store,
341 * linkage into the address_space->i_mmap interval tree.
342 *
343 * For private anonymous mappings, a pointer to a null terminated string
344 * in the user process containing the name given to the vma, or NULL
345 * if unnamed.
346 */
347 union {
348 struct {
349 struct rb_node rb;
350 unsigned long rb_subtree_last;
351 } shared;
352 const char __user *anon_name;
353 };
354
355 /*
356 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
357 * list, after a COW of one of the file pages. A MAP_SHARED vma
358 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
359 * or brk vma (with NULL file) can only be in an anon_vma list.
360 */
361 struct list_head anon_vma_chain; /* Serialized by mmap_lock &
362 * page_table_lock */
363 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
364
365 /* Function pointers to deal with this struct. */
366 const struct vm_operations_struct *vm_ops;
367
368 /* Information about our backing store: */
369 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
370 units */
371 struct file * vm_file; /* File we map to (can be NULL). */
372 void * vm_private_data; /* was vm_pte (shared mem) */
373
374 #ifdef CONFIG_SWAP
375 atomic_long_t swap_readahead_info;
376 #endif
377 #ifndef CONFIG_MMU
378 struct vm_region *vm_region; /* NOMMU mapping region */
379 #endif
380 #ifdef CONFIG_NUMA
381 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
382 #endif
383 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
384 #ifdef CONFIG_SPECULATIVE_PAGE_FAULT
385 seqcount_t vm_sequence;
386 atomic_t vm_ref_count; /* see vma_get(), vma_put() */
387 #endif
388
389 ANDROID_KABI_RESERVE(1);
390 ANDROID_KABI_RESERVE(2);
391 ANDROID_KABI_RESERVE(3);
392 ANDROID_KABI_RESERVE(4);
393 } __randomize_layout;
394
395 struct core_thread {
396 struct task_struct *task;
397 struct core_thread *next;
398 };
399
400 struct core_state {
401 atomic_t nr_threads;
402 struct core_thread dumper;
403 struct completion startup;
404 };
405
406 struct kioctx_table;
407 struct mm_struct {
408 struct {
409 struct vm_area_struct *mmap; /* list of VMAs */
410 struct rb_root mm_rb;
411 u64 vmacache_seqnum; /* per-thread vmacache */
412 #ifdef CONFIG_SPECULATIVE_PAGE_FAULT
413 rwlock_t mm_rb_lock;
414 #endif
415 #ifdef CONFIG_MMU
416 unsigned long (*get_unmapped_area) (struct file *filp,
417 unsigned long addr, unsigned long len,
418 unsigned long pgoff, unsigned long flags);
419 #endif
420 unsigned long mmap_base; /* base of mmap area */
421 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
422 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
423 /* Base adresses for compatible mmap() */
424 unsigned long mmap_compat_base;
425 unsigned long mmap_compat_legacy_base;
426 #endif
427 unsigned long task_size; /* size of task vm space */
428 unsigned long highest_vm_end; /* highest vma end address */
429 pgd_t * pgd;
430
431 #ifdef CONFIG_MEMBARRIER
432 /**
433 * @membarrier_state: Flags controlling membarrier behavior.
434 *
435 * This field is close to @pgd to hopefully fit in the same
436 * cache-line, which needs to be touched by switch_mm().
437 */
438 atomic_t membarrier_state;
439 #endif
440
441 /**
442 * @mm_users: The number of users including userspace.
443 *
444 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
445 * drops to 0 (i.e. when the task exits and there are no other
446 * temporary reference holders), we also release a reference on
447 * @mm_count (which may then free the &struct mm_struct if
448 * @mm_count also drops to 0).
449 */
450 atomic_t mm_users;
451
452 /**
453 * @mm_count: The number of references to &struct mm_struct
454 * (@mm_users count as 1).
455 *
456 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
457 * &struct mm_struct is freed.
458 */
459 atomic_t mm_count;
460
461 /**
462 * @has_pinned: Whether this mm has pinned any pages. This can
463 * be either replaced in the future by @pinned_vm when it
464 * becomes stable, or grow into a counter on its own. We're
465 * aggresive on this bit now - even if the pinned pages were
466 * unpinned later on, we'll still keep this bit set for the
467 * lifecycle of this mm just for simplicity.
468 */
469 atomic_t has_pinned;
470
471 #ifdef CONFIG_MMU
472 atomic_long_t pgtables_bytes; /* PTE page table pages */
473 #endif
474 int map_count; /* number of VMAs */
475
476 spinlock_t page_table_lock; /* Protects page tables and some
477 * counters
478 */
479 /*
480 * With some kernel config, the current mmap_lock's offset
481 * inside 'mm_struct' is at 0x120, which is very optimal, as
482 * its two hot fields 'count' and 'owner' sit in 2 different
483 * cachelines, and when mmap_lock is highly contended, both
484 * of the 2 fields will be accessed frequently, current layout
485 * will help to reduce cache bouncing.
486 *
487 * So please be careful with adding new fields before
488 * mmap_lock, which can easily push the 2 fields into one
489 * cacheline.
490 */
491 struct rw_semaphore mmap_lock;
492
493 struct list_head mmlist; /* List of maybe swapped mm's. These
494 * are globally strung together off
495 * init_mm.mmlist, and are protected
496 * by mmlist_lock
497 */
498
499
500 unsigned long hiwater_rss; /* High-watermark of RSS usage */
501 unsigned long hiwater_vm; /* High-water virtual memory usage */
502
503 unsigned long total_vm; /* Total pages mapped */
504 unsigned long locked_vm; /* Pages that have PG_mlocked set */
505 atomic64_t pinned_vm; /* Refcount permanently increased */
506 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
507 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
508 unsigned long stack_vm; /* VM_STACK */
509 unsigned long def_flags;
510
511 /**
512 * @write_protect_seq: Locked when any thread is write
513 * protecting pages mapped by this mm to enforce a later COW,
514 * for instance during page table copying for fork().
515 */
516 seqcount_t write_protect_seq;
517
518 spinlock_t arg_lock; /* protect the below fields */
519
520 unsigned long start_code, end_code, start_data, end_data;
521 unsigned long start_brk, brk, start_stack;
522 unsigned long arg_start, arg_end, env_start, env_end;
523
524 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
525
526 /*
527 * Special counters, in some configurations protected by the
528 * page_table_lock, in other configurations by being atomic.
529 */
530 struct mm_rss_stat rss_stat;
531
532 struct linux_binfmt *binfmt;
533
534 /* Architecture-specific MM context */
535 mm_context_t context;
536
537 unsigned long flags; /* Must use atomic bitops to access */
538
539 struct core_state *core_state; /* coredumping support */
540
541 #ifdef CONFIG_AIO
542 spinlock_t ioctx_lock;
543 struct kioctx_table __rcu *ioctx_table;
544 #endif
545 #ifdef CONFIG_MEMCG
546 /*
547 * "owner" points to a task that is regarded as the canonical
548 * user/owner of this mm. All of the following must be true in
549 * order for it to be changed:
550 *
551 * current == mm->owner
552 * current->mm != mm
553 * new_owner->mm == mm
554 * new_owner->alloc_lock is held
555 */
556 struct task_struct __rcu *owner;
557 #endif
558 struct user_namespace *user_ns;
559
560 /* store ref to file /proc/<pid>/exe symlink points to */
561 struct file __rcu *exe_file;
562 #ifdef CONFIG_MMU_NOTIFIER
563 struct mmu_notifier_subscriptions *notifier_subscriptions;
564 #endif
565 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
566 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
567 #endif
568 #ifdef CONFIG_NUMA_BALANCING
569 /*
570 * numa_next_scan is the next time that the PTEs will be marked
571 * pte_numa. NUMA hinting faults will gather statistics and
572 * migrate pages to new nodes if necessary.
573 */
574 unsigned long numa_next_scan;
575
576 /* Restart point for scanning and setting pte_numa */
577 unsigned long numa_scan_offset;
578
579 /* numa_scan_seq prevents two threads setting pte_numa */
580 int numa_scan_seq;
581 #endif
582 /*
583 * An operation with batched TLB flushing is going on. Anything
584 * that can move process memory needs to flush the TLB when
585 * moving a PROT_NONE or PROT_NUMA mapped page.
586 */
587 atomic_t tlb_flush_pending;
588 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
589 /* See flush_tlb_batched_pending() */
590 bool tlb_flush_batched;
591 #endif
592 struct uprobes_state uprobes_state;
593 #ifdef CONFIG_HUGETLB_PAGE
594 atomic_long_t hugetlb_usage;
595 #endif
596 struct work_struct async_put_work;
597
598 #ifdef CONFIG_IOMMU_SUPPORT
599 u32 pasid;
600 #endif
601
602 ANDROID_KABI_RESERVE(1);
603 } __randomize_layout;
604
605 /*
606 * The mm_cpumask needs to be at the end of mm_struct, because it
607 * is dynamically sized based on nr_cpu_ids.
608 */
609 unsigned long cpu_bitmap[];
610 };
611
612 extern struct mm_struct init_mm;
613
614 /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)615 static inline void mm_init_cpumask(struct mm_struct *mm)
616 {
617 unsigned long cpu_bitmap = (unsigned long)mm;
618
619 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
620 cpumask_clear((struct cpumask *)cpu_bitmap);
621 }
622
623 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)624 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
625 {
626 return (struct cpumask *)&mm->cpu_bitmap;
627 }
628
629 struct mmu_gather;
630 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
631 unsigned long start, unsigned long end);
632 extern void tlb_finish_mmu(struct mmu_gather *tlb,
633 unsigned long start, unsigned long end);
634
init_tlb_flush_pending(struct mm_struct * mm)635 static inline void init_tlb_flush_pending(struct mm_struct *mm)
636 {
637 atomic_set(&mm->tlb_flush_pending, 0);
638 }
639
inc_tlb_flush_pending(struct mm_struct * mm)640 static inline void inc_tlb_flush_pending(struct mm_struct *mm)
641 {
642 atomic_inc(&mm->tlb_flush_pending);
643 /*
644 * The only time this value is relevant is when there are indeed pages
645 * to flush. And we'll only flush pages after changing them, which
646 * requires the PTL.
647 *
648 * So the ordering here is:
649 *
650 * atomic_inc(&mm->tlb_flush_pending);
651 * spin_lock(&ptl);
652 * ...
653 * set_pte_at();
654 * spin_unlock(&ptl);
655 *
656 * spin_lock(&ptl)
657 * mm_tlb_flush_pending();
658 * ....
659 * spin_unlock(&ptl);
660 *
661 * flush_tlb_range();
662 * atomic_dec(&mm->tlb_flush_pending);
663 *
664 * Where the increment if constrained by the PTL unlock, it thus
665 * ensures that the increment is visible if the PTE modification is
666 * visible. After all, if there is no PTE modification, nobody cares
667 * about TLB flushes either.
668 *
669 * This very much relies on users (mm_tlb_flush_pending() and
670 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
671 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
672 * locks (PPC) the unlock of one doesn't order against the lock of
673 * another PTL.
674 *
675 * The decrement is ordered by the flush_tlb_range(), such that
676 * mm_tlb_flush_pending() will not return false unless all flushes have
677 * completed.
678 */
679 }
680
dec_tlb_flush_pending(struct mm_struct * mm)681 static inline void dec_tlb_flush_pending(struct mm_struct *mm)
682 {
683 /*
684 * See inc_tlb_flush_pending().
685 *
686 * This cannot be smp_mb__before_atomic() because smp_mb() simply does
687 * not order against TLB invalidate completion, which is what we need.
688 *
689 * Therefore we must rely on tlb_flush_*() to guarantee order.
690 */
691 atomic_dec(&mm->tlb_flush_pending);
692 }
693
mm_tlb_flush_pending(struct mm_struct * mm)694 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
695 {
696 /*
697 * Must be called after having acquired the PTL; orders against that
698 * PTLs release and therefore ensures that if we observe the modified
699 * PTE we must also observe the increment from inc_tlb_flush_pending().
700 *
701 * That is, it only guarantees to return true if there is a flush
702 * pending for _this_ PTL.
703 */
704 return atomic_read(&mm->tlb_flush_pending);
705 }
706
mm_tlb_flush_nested(struct mm_struct * mm)707 static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
708 {
709 /*
710 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
711 * for which there is a TLB flush pending in order to guarantee
712 * we've seen both that PTE modification and the increment.
713 *
714 * (no requirement on actually still holding the PTL, that is irrelevant)
715 */
716 return atomic_read(&mm->tlb_flush_pending) > 1;
717 }
718
719 struct vm_fault;
720
721 /**
722 * typedef vm_fault_t - Return type for page fault handlers.
723 *
724 * Page fault handlers return a bitmask of %VM_FAULT values.
725 */
726 typedef __bitwise unsigned int vm_fault_t;
727
728 /**
729 * enum vm_fault_reason - Page fault handlers return a bitmask of
730 * these values to tell the core VM what happened when handling the
731 * fault. Used to decide whether a process gets delivered SIGBUS or
732 * just gets major/minor fault counters bumped up.
733 *
734 * @VM_FAULT_OOM: Out Of Memory
735 * @VM_FAULT_SIGBUS: Bad access
736 * @VM_FAULT_MAJOR: Page read from storage
737 * @VM_FAULT_WRITE: Special case for get_user_pages
738 * @VM_FAULT_HWPOISON: Hit poisoned small page
739 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
740 * in upper bits
741 * @VM_FAULT_SIGSEGV: segmentation fault
742 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
743 * @VM_FAULT_LOCKED: ->fault locked the returned page
744 * @VM_FAULT_RETRY: ->fault blocked, must retry
745 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
746 * @VM_FAULT_DONE_COW: ->fault has fully handled COW
747 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
748 * fsync() to complete (for synchronous page faults
749 * in DAX)
750 * @VM_FAULT_HINDEX_MASK: mask HINDEX value
751 *
752 */
753 enum vm_fault_reason {
754 VM_FAULT_OOM = (__force vm_fault_t)0x000001,
755 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
756 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
757 VM_FAULT_WRITE = (__force vm_fault_t)0x000008,
758 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
759 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
760 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
761 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
762 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
763 VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
764 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
765 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
766 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
767 VM_FAULT_PTNOTSAME = (__force vm_fault_t)0x004000,
768 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
769 };
770
771 /* Encode hstate index for a hwpoisoned large page */
772 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
773 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
774
775 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
776 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
777 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
778
779 #define VM_FAULT_RESULT_TRACE \
780 { VM_FAULT_OOM, "OOM" }, \
781 { VM_FAULT_SIGBUS, "SIGBUS" }, \
782 { VM_FAULT_MAJOR, "MAJOR" }, \
783 { VM_FAULT_WRITE, "WRITE" }, \
784 { VM_FAULT_HWPOISON, "HWPOISON" }, \
785 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
786 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
787 { VM_FAULT_NOPAGE, "NOPAGE" }, \
788 { VM_FAULT_LOCKED, "LOCKED" }, \
789 { VM_FAULT_RETRY, "RETRY" }, \
790 { VM_FAULT_FALLBACK, "FALLBACK" }, \
791 { VM_FAULT_DONE_COW, "DONE_COW" }, \
792 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
793
794 struct vm_special_mapping {
795 const char *name; /* The name, e.g. "[vdso]". */
796
797 /*
798 * If .fault is not provided, this points to a
799 * NULL-terminated array of pages that back the special mapping.
800 *
801 * This must not be NULL unless .fault is provided.
802 */
803 struct page **pages;
804
805 /*
806 * If non-NULL, then this is called to resolve page faults
807 * on the special mapping. If used, .pages is not checked.
808 */
809 vm_fault_t (*fault)(const struct vm_special_mapping *sm,
810 struct vm_area_struct *vma,
811 struct vm_fault *vmf);
812
813 int (*mremap)(const struct vm_special_mapping *sm,
814 struct vm_area_struct *new_vma);
815 };
816
817 enum tlb_flush_reason {
818 TLB_FLUSH_ON_TASK_SWITCH,
819 TLB_REMOTE_SHOOTDOWN,
820 TLB_LOCAL_SHOOTDOWN,
821 TLB_LOCAL_MM_SHOOTDOWN,
822 TLB_REMOTE_SEND_IPI,
823 NR_TLB_FLUSH_REASONS,
824 };
825
826 /*
827 * A swap entry has to fit into a "unsigned long", as the entry is hidden
828 * in the "index" field of the swapper address space.
829 */
830 typedef struct {
831 unsigned long val;
832 } swp_entry_t;
833
834 /* Return the name for an anonymous mapping or NULL for a file-backed mapping */
vma_get_anon_name(struct vm_area_struct * vma)835 static inline const char __user *vma_get_anon_name(struct vm_area_struct *vma)
836 {
837 if (vma->vm_file)
838 return NULL;
839
840 return vma->anon_name;
841 }
842
843 #endif /* _LINUX_MM_TYPES_H */
844