Line data Source code
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 : * @dma_addr: might require a 64-bit value even on
101 : * 32-bit architectures.
102 : */
103 : dma_addr_t dma_addr;
104 : };
105 : struct { /* slab, slob and slub */
106 : union {
107 : struct list_head slab_list;
108 : struct { /* Partial pages */
109 : struct page *next;
110 : #ifdef CONFIG_64BIT
111 : int pages; /* Nr of pages left */
112 : int pobjects; /* Approximate count */
113 : #else
114 : short int pages;
115 : short int pobjects;
116 : #endif
117 : };
118 : };
119 : struct kmem_cache *slab_cache; /* not slob */
120 : /* Double-word boundary */
121 : void *freelist; /* first free object */
122 : union {
123 : void *s_mem; /* slab: first object */
124 : unsigned long counters; /* SLUB */
125 : struct { /* SLUB */
126 : unsigned inuse:16;
127 : unsigned objects:15;
128 : unsigned frozen:1;
129 : };
130 : };
131 : };
132 : struct { /* Tail pages of compound page */
133 : unsigned long compound_head; /* Bit zero is set */
134 :
135 : /* First tail page only */
136 : unsigned char compound_dtor;
137 : unsigned char compound_order;
138 : atomic_t compound_mapcount;
139 : unsigned int compound_nr; /* 1 << compound_order */
140 : };
141 : struct { /* Second tail page of compound page */
142 : unsigned long _compound_pad_1; /* compound_head */
143 : atomic_t hpage_pinned_refcount;
144 : /* For both global and memcg */
145 : struct list_head deferred_list;
146 : };
147 : struct { /* Page table pages */
148 : unsigned long _pt_pad_1; /* compound_head */
149 : pgtable_t pmd_huge_pte; /* protected by page->ptl */
150 : unsigned long _pt_pad_2; /* mapping */
151 : union {
152 : struct mm_struct *pt_mm; /* x86 pgds only */
153 : atomic_t pt_frag_refcount; /* powerpc */
154 : };
155 : #if ALLOC_SPLIT_PTLOCKS
156 : spinlock_t *ptl;
157 : #else
158 : spinlock_t ptl;
159 : #endif
160 : };
161 : struct { /* ZONE_DEVICE pages */
162 : /** @pgmap: Points to the hosting device page map. */
163 : struct dev_pagemap *pgmap;
164 : void *zone_device_data;
165 : /*
166 : * ZONE_DEVICE private pages are counted as being
167 : * mapped so the next 3 words hold the mapping, index,
168 : * and private fields from the source anonymous or
169 : * page cache page while the page is migrated to device
170 : * private memory.
171 : * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
172 : * use the mapping, index, and private fields when
173 : * pmem backed DAX files are mapped.
174 : */
175 : };
176 :
177 : /** @rcu_head: You can use this to free a page by RCU. */
178 : struct rcu_head rcu_head;
179 : };
180 :
181 : union { /* This union is 4 bytes in size. */
182 : /*
183 : * If the page can be mapped to userspace, encodes the number
184 : * of times this page is referenced by a page table.
185 : */
186 : atomic_t _mapcount;
187 :
188 : /*
189 : * If the page is neither PageSlab nor mappable to userspace,
190 : * the value stored here may help determine what this page
191 : * is used for. See page-flags.h for a list of page types
192 : * which are currently stored here.
193 : */
194 : unsigned int page_type;
195 :
196 : unsigned int active; /* SLAB */
197 : int units; /* SLOB */
198 : };
199 :
200 : /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
201 : atomic_t _refcount;
202 :
203 : #ifdef CONFIG_MEMCG
204 : unsigned long memcg_data;
205 : #endif
206 :
207 : /*
208 : * On machines where all RAM is mapped into kernel address space,
209 : * we can simply calculate the virtual address. On machines with
210 : * highmem some memory is mapped into kernel virtual memory
211 : * dynamically, so we need a place to store that address.
212 : * Note that this field could be 16 bits on x86 ... ;)
213 : *
214 : * Architectures with slow multiplication can define
215 : * WANT_PAGE_VIRTUAL in asm/page.h
216 : */
217 : #if defined(WANT_PAGE_VIRTUAL)
218 : void *virtual; /* Kernel virtual address (NULL if
219 : not kmapped, ie. highmem) */
220 : #endif /* WANT_PAGE_VIRTUAL */
221 :
222 : #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
223 : int _last_cpupid;
224 : #endif
225 : } _struct_page_alignment;
226 :
227 35325 : static inline atomic_t *compound_mapcount_ptr(struct page *page)
228 : {
229 35325 : return &page[1].compound_mapcount;
230 : }
231 :
232 10179 : static inline atomic_t *compound_pincount_ptr(struct page *page)
233 : {
234 10179 : return &page[2].hpage_pinned_refcount;
235 : }
236 :
237 : /*
238 : * Used for sizing the vmemmap region on some architectures
239 : */
240 : #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page)))
241 :
242 : #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
243 : #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
244 :
245 : #define page_private(page) ((page)->private)
246 :
247 529505 : static inline void set_page_private(struct page *page, unsigned long private)
248 : {
249 432325 : page->private = private;
250 0 : }
251 :
252 : struct page_frag_cache {
253 : void * va;
254 : #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
255 : __u16 offset;
256 : __u16 size;
257 : #else
258 : __u32 offset;
259 : #endif
260 : /* we maintain a pagecount bias, so that we dont dirty cache line
261 : * containing page->_refcount every time we allocate a fragment.
262 : */
263 : unsigned int pagecnt_bias;
264 : bool pfmemalloc;
265 : };
266 :
267 : typedef unsigned long vm_flags_t;
268 :
269 : /*
270 : * A region containing a mapping of a non-memory backed file under NOMMU
271 : * conditions. These are held in a global tree and are pinned by the VMAs that
272 : * map parts of them.
273 : */
274 : struct vm_region {
275 : struct rb_node vm_rb; /* link in global region tree */
276 : vm_flags_t vm_flags; /* VMA vm_flags */
277 : unsigned long vm_start; /* start address of region */
278 : unsigned long vm_end; /* region initialised to here */
279 : unsigned long vm_top; /* region allocated to here */
280 : unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
281 : struct file *vm_file; /* the backing file or NULL */
282 :
283 : int vm_usage; /* region usage count (access under nommu_region_sem) */
284 : bool vm_icache_flushed : 1; /* true if the icache has been flushed for
285 : * this region */
286 : };
287 :
288 : #ifdef CONFIG_USERFAULTFD
289 : #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
290 : struct vm_userfaultfd_ctx {
291 : struct userfaultfd_ctx *ctx;
292 : };
293 : #else /* CONFIG_USERFAULTFD */
294 : #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
295 : struct vm_userfaultfd_ctx {};
296 : #endif /* CONFIG_USERFAULTFD */
297 :
298 : /*
299 : * This struct describes a virtual memory area. There is one of these
300 : * per VM-area/task. A VM area is any part of the process virtual memory
301 : * space that has a special rule for the page-fault handlers (ie a shared
302 : * library, the executable area etc).
303 : */
304 : struct vm_area_struct {
305 : /* The first cache line has the info for VMA tree walking. */
306 :
307 : unsigned long vm_start; /* Our start address within vm_mm. */
308 : unsigned long vm_end; /* The first byte after our end address
309 : within vm_mm. */
310 :
311 : /* linked list of VM areas per task, sorted by address */
312 : struct vm_area_struct *vm_next, *vm_prev;
313 :
314 : struct rb_node vm_rb;
315 :
316 : /*
317 : * Largest free memory gap in bytes to the left of this VMA.
318 : * Either between this VMA and vma->vm_prev, or between one of the
319 : * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
320 : * get_unmapped_area find a free area of the right size.
321 : */
322 : unsigned long rb_subtree_gap;
323 :
324 : /* Second cache line starts here. */
325 :
326 : struct mm_struct *vm_mm; /* The address space we belong to. */
327 :
328 : /*
329 : * Access permissions of this VMA.
330 : * See vmf_insert_mixed_prot() for discussion.
331 : */
332 : pgprot_t vm_page_prot;
333 : unsigned long vm_flags; /* Flags, see mm.h. */
334 :
335 : /*
336 : * For areas with an address space and backing store,
337 : * linkage into the address_space->i_mmap interval tree.
338 : */
339 : struct {
340 : struct rb_node rb;
341 : unsigned long rb_subtree_last;
342 : } shared;
343 :
344 : /*
345 : * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
346 : * list, after a COW of one of the file pages. A MAP_SHARED vma
347 : * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
348 : * or brk vma (with NULL file) can only be in an anon_vma list.
349 : */
350 : struct list_head anon_vma_chain; /* Serialized by mmap_lock &
351 : * page_table_lock */
352 : struct anon_vma *anon_vma; /* Serialized by page_table_lock */
353 :
354 : /* Function pointers to deal with this struct. */
355 : const struct vm_operations_struct *vm_ops;
356 :
357 : /* Information about our backing store: */
358 : unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
359 : units */
360 : struct file * vm_file; /* File we map to (can be NULL). */
361 : void * vm_private_data; /* was vm_pte (shared mem) */
362 :
363 : #ifdef CONFIG_SWAP
364 : atomic_long_t swap_readahead_info;
365 : #endif
366 : #ifndef CONFIG_MMU
367 : struct vm_region *vm_region; /* NOMMU mapping region */
368 : #endif
369 : #ifdef CONFIG_NUMA
370 : struct mempolicy *vm_policy; /* NUMA policy for the VMA */
371 : #endif
372 : struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
373 : } __randomize_layout;
374 :
375 : struct core_thread {
376 : struct task_struct *task;
377 : struct core_thread *next;
378 : };
379 :
380 : struct core_state {
381 : atomic_t nr_threads;
382 : struct core_thread dumper;
383 : struct completion startup;
384 : };
385 :
386 : struct kioctx_table;
387 : struct mm_struct {
388 : struct {
389 : struct vm_area_struct *mmap; /* list of VMAs */
390 : struct rb_root mm_rb;
391 : u64 vmacache_seqnum; /* per-thread vmacache */
392 : #ifdef CONFIG_MMU
393 : unsigned long (*get_unmapped_area) (struct file *filp,
394 : unsigned long addr, unsigned long len,
395 : unsigned long pgoff, unsigned long flags);
396 : #endif
397 : unsigned long mmap_base; /* base of mmap area */
398 : unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
399 : #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
400 : /* Base adresses for compatible mmap() */
401 : unsigned long mmap_compat_base;
402 : unsigned long mmap_compat_legacy_base;
403 : #endif
404 : unsigned long task_size; /* size of task vm space */
405 : unsigned long highest_vm_end; /* highest vma end address */
406 : pgd_t * pgd;
407 :
408 : #ifdef CONFIG_MEMBARRIER
409 : /**
410 : * @membarrier_state: Flags controlling membarrier behavior.
411 : *
412 : * This field is close to @pgd to hopefully fit in the same
413 : * cache-line, which needs to be touched by switch_mm().
414 : */
415 : atomic_t membarrier_state;
416 : #endif
417 :
418 : /**
419 : * @mm_users: The number of users including userspace.
420 : *
421 : * Use mmget()/mmget_not_zero()/mmput() to modify. When this
422 : * drops to 0 (i.e. when the task exits and there are no other
423 : * temporary reference holders), we also release a reference on
424 : * @mm_count (which may then free the &struct mm_struct if
425 : * @mm_count also drops to 0).
426 : */
427 : atomic_t mm_users;
428 :
429 : /**
430 : * @mm_count: The number of references to &struct mm_struct
431 : * (@mm_users count as 1).
432 : *
433 : * Use mmgrab()/mmdrop() to modify. When this drops to 0, the
434 : * &struct mm_struct is freed.
435 : */
436 : atomic_t mm_count;
437 :
438 : /**
439 : * @has_pinned: Whether this mm has pinned any pages. This can
440 : * be either replaced in the future by @pinned_vm when it
441 : * becomes stable, or grow into a counter on its own. We're
442 : * aggresive on this bit now - even if the pinned pages were
443 : * unpinned later on, we'll still keep this bit set for the
444 : * lifecycle of this mm just for simplicity.
445 : */
446 : atomic_t has_pinned;
447 :
448 : /**
449 : * @write_protect_seq: Locked when any thread is write
450 : * protecting pages mapped by this mm to enforce a later COW,
451 : * for instance during page table copying for fork().
452 : */
453 : seqcount_t write_protect_seq;
454 :
455 : #ifdef CONFIG_MMU
456 : atomic_long_t pgtables_bytes; /* PTE page table pages */
457 : #endif
458 : int map_count; /* number of VMAs */
459 :
460 : spinlock_t page_table_lock; /* Protects page tables and some
461 : * counters
462 : */
463 : struct rw_semaphore mmap_lock;
464 :
465 : struct list_head mmlist; /* List of maybe swapped mm's. These
466 : * are globally strung together off
467 : * init_mm.mmlist, and are protected
468 : * by mmlist_lock
469 : */
470 :
471 :
472 : unsigned long hiwater_rss; /* High-watermark of RSS usage */
473 : unsigned long hiwater_vm; /* High-water virtual memory usage */
474 :
475 : unsigned long total_vm; /* Total pages mapped */
476 : unsigned long locked_vm; /* Pages that have PG_mlocked set */
477 : atomic64_t pinned_vm; /* Refcount permanently increased */
478 : unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
479 : unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
480 : unsigned long stack_vm; /* VM_STACK */
481 : unsigned long def_flags;
482 :
483 : spinlock_t arg_lock; /* protect the below fields */
484 : unsigned long start_code, end_code, start_data, end_data;
485 : unsigned long start_brk, brk, start_stack;
486 : unsigned long arg_start, arg_end, env_start, env_end;
487 :
488 : unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
489 :
490 : /*
491 : * Special counters, in some configurations protected by the
492 : * page_table_lock, in other configurations by being atomic.
493 : */
494 : struct mm_rss_stat rss_stat;
495 :
496 : struct linux_binfmt *binfmt;
497 :
498 : /* Architecture-specific MM context */
499 : mm_context_t context;
500 :
501 : unsigned long flags; /* Must use atomic bitops to access */
502 :
503 : struct core_state *core_state; /* coredumping support */
504 :
505 : #ifdef CONFIG_AIO
506 : spinlock_t ioctx_lock;
507 : struct kioctx_table __rcu *ioctx_table;
508 : #endif
509 : #ifdef CONFIG_MEMCG
510 : /*
511 : * "owner" points to a task that is regarded as the canonical
512 : * user/owner of this mm. All of the following must be true in
513 : * order for it to be changed:
514 : *
515 : * current == mm->owner
516 : * current->mm != mm
517 : * new_owner->mm == mm
518 : * new_owner->alloc_lock is held
519 : */
520 : struct task_struct __rcu *owner;
521 : #endif
522 : struct user_namespace *user_ns;
523 :
524 : /* store ref to file /proc/<pid>/exe symlink points to */
525 : struct file __rcu *exe_file;
526 : #ifdef CONFIG_MMU_NOTIFIER
527 : struct mmu_notifier_subscriptions *notifier_subscriptions;
528 : #endif
529 : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
530 : pgtable_t pmd_huge_pte; /* protected by page_table_lock */
531 : #endif
532 : #ifdef CONFIG_NUMA_BALANCING
533 : /*
534 : * numa_next_scan is the next time that the PTEs will be marked
535 : * pte_numa. NUMA hinting faults will gather statistics and
536 : * migrate pages to new nodes if necessary.
537 : */
538 : unsigned long numa_next_scan;
539 :
540 : /* Restart point for scanning and setting pte_numa */
541 : unsigned long numa_scan_offset;
542 :
543 : /* numa_scan_seq prevents two threads setting pte_numa */
544 : int numa_scan_seq;
545 : #endif
546 : /*
547 : * An operation with batched TLB flushing is going on. Anything
548 : * that can move process memory needs to flush the TLB when
549 : * moving a PROT_NONE or PROT_NUMA mapped page.
550 : */
551 : atomic_t tlb_flush_pending;
552 : #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
553 : /* See flush_tlb_batched_pending() */
554 : bool tlb_flush_batched;
555 : #endif
556 : struct uprobes_state uprobes_state;
557 : #ifdef CONFIG_HUGETLB_PAGE
558 : atomic_long_t hugetlb_usage;
559 : #endif
560 : struct work_struct async_put_work;
561 :
562 : #ifdef CONFIG_IOMMU_SUPPORT
563 : u32 pasid;
564 : #endif
565 : } __randomize_layout;
566 :
567 : /*
568 : * The mm_cpumask needs to be at the end of mm_struct, because it
569 : * is dynamically sized based on nr_cpu_ids.
570 : */
571 : unsigned long cpu_bitmap[];
572 : };
573 :
574 : extern struct mm_struct init_mm;
575 :
576 : /* Pointer magic because the dynamic array size confuses some compilers. */
577 2019 : static inline void mm_init_cpumask(struct mm_struct *mm)
578 : {
579 2019 : unsigned long cpu_bitmap = (unsigned long)mm;
580 :
581 2019 : cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
582 2019 : cpumask_clear((struct cpumask *)cpu_bitmap);
583 : }
584 :
585 : /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
586 126513 : static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
587 : {
588 126513 : return (struct cpumask *)&mm->cpu_bitmap;
589 : }
590 :
591 : struct mmu_gather;
592 : extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
593 : extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
594 : extern void tlb_finish_mmu(struct mmu_gather *tlb);
595 :
596 2019 : static inline void init_tlb_flush_pending(struct mm_struct *mm)
597 : {
598 2019 : atomic_set(&mm->tlb_flush_pending, 0);
599 : }
600 :
601 29451 : static inline void inc_tlb_flush_pending(struct mm_struct *mm)
602 : {
603 29451 : atomic_inc(&mm->tlb_flush_pending);
604 : /*
605 : * The only time this value is relevant is when there are indeed pages
606 : * to flush. And we'll only flush pages after changing them, which
607 : * requires the PTL.
608 : *
609 : * So the ordering here is:
610 : *
611 : * atomic_inc(&mm->tlb_flush_pending);
612 : * spin_lock(&ptl);
613 : * ...
614 : * set_pte_at();
615 : * spin_unlock(&ptl);
616 : *
617 : * spin_lock(&ptl)
618 : * mm_tlb_flush_pending();
619 : * ....
620 : * spin_unlock(&ptl);
621 : *
622 : * flush_tlb_range();
623 : * atomic_dec(&mm->tlb_flush_pending);
624 : *
625 : * Where the increment if constrained by the PTL unlock, it thus
626 : * ensures that the increment is visible if the PTE modification is
627 : * visible. After all, if there is no PTE modification, nobody cares
628 : * about TLB flushes either.
629 : *
630 : * This very much relies on users (mm_tlb_flush_pending() and
631 : * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
632 : * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
633 : * locks (PPC) the unlock of one doesn't order against the lock of
634 : * another PTL.
635 : *
636 : * The decrement is ordered by the flush_tlb_range(), such that
637 : * mm_tlb_flush_pending() will not return false unless all flushes have
638 : * completed.
639 : */
640 29451 : }
641 :
642 29450 : static inline void dec_tlb_flush_pending(struct mm_struct *mm)
643 : {
644 : /*
645 : * See inc_tlb_flush_pending().
646 : *
647 : * This cannot be smp_mb__before_atomic() because smp_mb() simply does
648 : * not order against TLB invalidate completion, which is what we need.
649 : *
650 : * Therefore we must rely on tlb_flush_*() to guarantee order.
651 : */
652 29450 : atomic_dec(&mm->tlb_flush_pending);
653 29451 : }
654 :
655 0 : static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
656 : {
657 : /*
658 : * Must be called after having acquired the PTL; orders against that
659 : * PTLs release and therefore ensures that if we observe the modified
660 : * PTE we must also observe the increment from inc_tlb_flush_pending().
661 : *
662 : * That is, it only guarantees to return true if there is a flush
663 : * pending for _this_ PTL.
664 : */
665 0 : return atomic_read(&mm->tlb_flush_pending);
666 : }
667 :
668 21474 : static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
669 : {
670 : /*
671 : * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
672 : * for which there is a TLB flush pending in order to guarantee
673 : * we've seen both that PTE modification and the increment.
674 : *
675 : * (no requirement on actually still holding the PTL, that is irrelevant)
676 : */
677 21474 : return atomic_read(&mm->tlb_flush_pending) > 1;
678 : }
679 :
680 : struct vm_fault;
681 :
682 : /**
683 : * typedef vm_fault_t - Return type for page fault handlers.
684 : *
685 : * Page fault handlers return a bitmask of %VM_FAULT values.
686 : */
687 : typedef __bitwise unsigned int vm_fault_t;
688 :
689 : /**
690 : * enum vm_fault_reason - Page fault handlers return a bitmask of
691 : * these values to tell the core VM what happened when handling the
692 : * fault. Used to decide whether a process gets delivered SIGBUS or
693 : * just gets major/minor fault counters bumped up.
694 : *
695 : * @VM_FAULT_OOM: Out Of Memory
696 : * @VM_FAULT_SIGBUS: Bad access
697 : * @VM_FAULT_MAJOR: Page read from storage
698 : * @VM_FAULT_WRITE: Special case for get_user_pages
699 : * @VM_FAULT_HWPOISON: Hit poisoned small page
700 : * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
701 : * in upper bits
702 : * @VM_FAULT_SIGSEGV: segmentation fault
703 : * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page
704 : * @VM_FAULT_LOCKED: ->fault locked the returned page
705 : * @VM_FAULT_RETRY: ->fault blocked, must retry
706 : * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small
707 : * @VM_FAULT_DONE_COW: ->fault has fully handled COW
708 : * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs
709 : * fsync() to complete (for synchronous page faults
710 : * in DAX)
711 : * @VM_FAULT_HINDEX_MASK: mask HINDEX value
712 : *
713 : */
714 : enum vm_fault_reason {
715 : VM_FAULT_OOM = (__force vm_fault_t)0x000001,
716 : VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002,
717 : VM_FAULT_MAJOR = (__force vm_fault_t)0x000004,
718 : VM_FAULT_WRITE = (__force vm_fault_t)0x000008,
719 : VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010,
720 : VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
721 : VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040,
722 : VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100,
723 : VM_FAULT_LOCKED = (__force vm_fault_t)0x000200,
724 : VM_FAULT_RETRY = (__force vm_fault_t)0x000400,
725 : VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800,
726 : VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000,
727 : VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000,
728 : VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000,
729 : };
730 :
731 : /* Encode hstate index for a hwpoisoned large page */
732 : #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
733 : #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
734 :
735 : #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \
736 : VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \
737 : VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
738 :
739 : #define VM_FAULT_RESULT_TRACE \
740 : { VM_FAULT_OOM, "OOM" }, \
741 : { VM_FAULT_SIGBUS, "SIGBUS" }, \
742 : { VM_FAULT_MAJOR, "MAJOR" }, \
743 : { VM_FAULT_WRITE, "WRITE" }, \
744 : { VM_FAULT_HWPOISON, "HWPOISON" }, \
745 : { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
746 : { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
747 : { VM_FAULT_NOPAGE, "NOPAGE" }, \
748 : { VM_FAULT_LOCKED, "LOCKED" }, \
749 : { VM_FAULT_RETRY, "RETRY" }, \
750 : { VM_FAULT_FALLBACK, "FALLBACK" }, \
751 : { VM_FAULT_DONE_COW, "DONE_COW" }, \
752 : { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
753 :
754 : struct vm_special_mapping {
755 : const char *name; /* The name, e.g. "[vdso]". */
756 :
757 : /*
758 : * If .fault is not provided, this points to a
759 : * NULL-terminated array of pages that back the special mapping.
760 : *
761 : * This must not be NULL unless .fault is provided.
762 : */
763 : struct page **pages;
764 :
765 : /*
766 : * If non-NULL, then this is called to resolve page faults
767 : * on the special mapping. If used, .pages is not checked.
768 : */
769 : vm_fault_t (*fault)(const struct vm_special_mapping *sm,
770 : struct vm_area_struct *vma,
771 : struct vm_fault *vmf);
772 :
773 : int (*mremap)(const struct vm_special_mapping *sm,
774 : struct vm_area_struct *new_vma);
775 : };
776 :
777 : enum tlb_flush_reason {
778 : TLB_FLUSH_ON_TASK_SWITCH,
779 : TLB_REMOTE_SHOOTDOWN,
780 : TLB_LOCAL_SHOOTDOWN,
781 : TLB_LOCAL_MM_SHOOTDOWN,
782 : TLB_REMOTE_SEND_IPI,
783 : NR_TLB_FLUSH_REASONS,
784 : };
785 :
786 : /*
787 : * A swap entry has to fit into a "unsigned long", as the entry is hidden
788 : * in the "index" field of the swapper address space.
789 : */
790 : typedef struct {
791 : unsigned long val;
792 : } swp_entry_t;
793 :
794 : #endif /* _LINUX_MM_TYPES_H */
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