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/maple_tree.h>
13  #include <linux/rwsem.h>
14  #include <linux/completion.h>
15  #include <linux/cpumask.h>
16  #include <linux/uprobes.h>
17  #include <linux/rcupdate.h>
18  #include <linux/page-flags-layout.h>
19  #include <linux/workqueue.h>
20  #include <linux/seqlock.h>
21  #include <linux/percpu_counter.h>
22  
23  #include <asm/mmu.h>
24  
25  #ifndef AT_VECTOR_SIZE_ARCH
26  #define AT_VECTOR_SIZE_ARCH 0
27  #endif
28  #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
29  
30  #define INIT_PASID	0
31  
32  struct address_space;
33  struct mem_cgroup;
34  
35  /*
36   * Each physical page in the system has a struct page associated with
37   * it to keep track of whatever it is we are using the page for at the
38   * moment. Note that we have no way to track which tasks are using
39   * a page, though if it is a pagecache page, rmap structures can tell us
40   * who is mapping it.
41   *
42   * If you allocate the page using alloc_pages(), you can use some of the
43   * space in struct page for your own purposes.  The five words in the main
44   * union are available, except for bit 0 of the first word which must be
45   * kept clear.  Many users use this word to store a pointer to an object
46   * which is guaranteed to be aligned.  If you use the same storage as
47   * page->mapping, you must restore it to NULL before freeing the page.
48   *
49   * The mapcount field must not be used for own purposes.
50   *
51   * If you want to use the refcount field, it must be used in such a way
52   * that other CPUs temporarily incrementing and then decrementing the
53   * refcount does not cause problems.  On receiving the page from
54   * alloc_pages(), the refcount will be positive.
55   *
56   * If you allocate pages of order > 0, you can use some of the fields
57   * in each subpage, but you may need to restore some of their values
58   * afterwards.
59   *
60   * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
61   * That requires that freelist & counters in struct slab be adjacent and
62   * double-word aligned. Because struct slab currently just reinterprets the
63   * bits of struct page, we align all struct pages to double-word boundaries,
64   * and ensure that 'freelist' is aligned within struct slab.
65   */
66  #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
67  #define _struct_page_alignment	__aligned(2 * sizeof(unsigned long))
68  #else
69  #define _struct_page_alignment	__aligned(sizeof(unsigned long))
70  #endif
71  
72  struct page {
73  	unsigned long flags;		/* Atomic flags, some possibly
74  					 * updated asynchronously */
75  	/*
76  	 * Five words (20/40 bytes) are available in this union.
77  	 * WARNING: bit 0 of the first word is used for PageTail(). That
78  	 * means the other users of this union MUST NOT use the bit to
79  	 * avoid collision and false-positive PageTail().
80  	 */
81  	union {
82  		struct {	/* Page cache and anonymous pages */
83  			/**
84  			 * @lru: Pageout list, eg. active_list protected by
85  			 * lruvec->lru_lock.  Sometimes used as a generic list
86  			 * by the page owner.
87  			 */
88  			union {
89  				struct list_head lru;
90  
91  				/* Or, for the Unevictable "LRU list" slot */
92  				struct {
93  					/* Always even, to negate PageTail */
94  					void *__filler;
95  					/* Count page's or folio's mlocks */
96  					unsigned int mlock_count;
97  				};
98  
99  				/* Or, free page */
100  				struct list_head buddy_list;
101  				struct list_head pcp_list;
102  			};
103  			/* See page-flags.h for PAGE_MAPPING_FLAGS */
104  			struct address_space *mapping;
105  			union {
106  				pgoff_t index;		/* Our offset within mapping. */
107  				unsigned long share;	/* share count for fsdax */
108  			};
109  			/**
110  			 * @private: Mapping-private opaque data.
111  			 * Usually used for buffer_heads if PagePrivate.
112  			 * Used for swp_entry_t if swapcache flag set.
113  			 * Indicates order in the buddy system if PageBuddy.
114  			 */
115  			unsigned long private;
116  		};
117  		struct {	/* page_pool used by netstack */
118  			/**
119  			 * @pp_magic: magic value to avoid recycling non
120  			 * page_pool allocated pages.
121  			 */
122  			unsigned long pp_magic;
123  			struct page_pool *pp;
124  			unsigned long _pp_mapping_pad;
125  			unsigned long dma_addr;
126  			atomic_long_t pp_ref_count;
127  		};
128  		struct {	/* Tail pages of compound page */
129  			unsigned long compound_head;	/* Bit zero is set */
130  		};
131  		struct {	/* ZONE_DEVICE pages */
132  			/** @pgmap: Points to the hosting device page map. */
133  			struct dev_pagemap *pgmap;
134  			void *zone_device_data;
135  			/*
136  			 * ZONE_DEVICE private pages are counted as being
137  			 * mapped so the next 3 words hold the mapping, index,
138  			 * and private fields from the source anonymous or
139  			 * page cache page while the page is migrated to device
140  			 * private memory.
141  			 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
142  			 * use the mapping, index, and private fields when
143  			 * pmem backed DAX files are mapped.
144  			 */
145  		};
146  
147  		/** @rcu_head: You can use this to free a page by RCU. */
148  		struct rcu_head rcu_head;
149  	};
150  
151  	union {		/* This union is 4 bytes in size. */
152  		/*
153  		 * For head pages of typed folios, the value stored here
154  		 * allows for determining what this page is used for. The
155  		 * tail pages of typed folios will not store a type
156  		 * (page_type == _mapcount == -1).
157  		 *
158  		 * See page-flags.h for a list of page types which are currently
159  		 * stored here.
160  		 *
161  		 * Owners of typed folios may reuse the lower 16 bit of the
162  		 * head page page_type field after setting the page type,
163  		 * but must reset these 16 bit to -1 before clearing the
164  		 * page type.
165  		 */
166  		unsigned int page_type;
167  
168  		/*
169  		 * For pages that are part of non-typed folios for which mappings
170  		 * are tracked via the RMAP, encodes the number of times this page
171  		 * is directly referenced by a page table.
172  		 *
173  		 * Note that the mapcount is always initialized to -1, so that
174  		 * transitions both from it and to it can be tracked, using
175  		 * atomic_inc_and_test() and atomic_add_negative(-1).
176  		 */
177  		atomic_t _mapcount;
178  	};
179  
180  	/* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
181  	atomic_t _refcount;
182  
183  #ifdef CONFIG_MEMCG
184  	unsigned long memcg_data;
185  #elif defined(CONFIG_SLAB_OBJ_EXT)
186  	unsigned long _unused_slab_obj_exts;
187  #endif
188  
189  	/*
190  	 * On machines where all RAM is mapped into kernel address space,
191  	 * we can simply calculate the virtual address. On machines with
192  	 * highmem some memory is mapped into kernel virtual memory
193  	 * dynamically, so we need a place to store that address.
194  	 * Note that this field could be 16 bits on x86 ... ;)
195  	 *
196  	 * Architectures with slow multiplication can define
197  	 * WANT_PAGE_VIRTUAL in asm/page.h
198  	 */
199  #if defined(WANT_PAGE_VIRTUAL)
200  	void *virtual;			/* Kernel virtual address (NULL if
201  					   not kmapped, ie. highmem) */
202  #endif /* WANT_PAGE_VIRTUAL */
203  
204  #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
205  	int _last_cpupid;
206  #endif
207  
208  #ifdef CONFIG_KMSAN
209  	/*
210  	 * KMSAN metadata for this page:
211  	 *  - shadow page: every bit indicates whether the corresponding
212  	 *    bit of the original page is initialized (0) or not (1);
213  	 *  - origin page: every 4 bytes contain an id of the stack trace
214  	 *    where the uninitialized value was created.
215  	 */
216  	struct page *kmsan_shadow;
217  	struct page *kmsan_origin;
218  #endif
219  } _struct_page_alignment;
220  
221  /*
222   * struct encoded_page - a nonexistent type marking this pointer
223   *
224   * An 'encoded_page' pointer is a pointer to a regular 'struct page', but
225   * with the low bits of the pointer indicating extra context-dependent
226   * information. Only used in mmu_gather handling, and this acts as a type
227   * system check on that use.
228   *
229   * We only really have two guaranteed bits in general, although you could
230   * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
231   * for more.
232   *
233   * Use the supplied helper functions to endcode/decode the pointer and bits.
234   */
235  struct encoded_page;
236  
237  #define ENCODED_PAGE_BITS			3ul
238  
239  /* Perform rmap removal after we have flushed the TLB. */
240  #define ENCODED_PAGE_BIT_DELAY_RMAP		1ul
241  
242  /*
243   * The next item in an encoded_page array is the "nr_pages" argument, specifying
244   * the number of consecutive pages starting from this page, that all belong to
245   * the same folio. For example, "nr_pages" corresponds to the number of folio
246   * references that must be dropped. If this bit is not set, "nr_pages" is
247   * implicitly 1.
248   */
249  #define ENCODED_PAGE_BIT_NR_PAGES_NEXT		2ul
250  
encode_page(struct page * page,unsigned long flags)251  static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
252  {
253  	BUILD_BUG_ON(flags > ENCODED_PAGE_BITS);
254  	return (struct encoded_page *)(flags | (unsigned long)page);
255  }
256  
encoded_page_flags(struct encoded_page * page)257  static inline unsigned long encoded_page_flags(struct encoded_page *page)
258  {
259  	return ENCODED_PAGE_BITS & (unsigned long)page;
260  }
261  
encoded_page_ptr(struct encoded_page * page)262  static inline struct page *encoded_page_ptr(struct encoded_page *page)
263  {
264  	return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page);
265  }
266  
encode_nr_pages(unsigned long nr)267  static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr)
268  {
269  	VM_WARN_ON_ONCE((nr << 2) >> 2 != nr);
270  	return (struct encoded_page *)(nr << 2);
271  }
272  
encoded_nr_pages(struct encoded_page * page)273  static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page)
274  {
275  	return ((unsigned long)page) >> 2;
276  }
277  
278  /*
279   * A swap entry has to fit into a "unsigned long", as the entry is hidden
280   * in the "index" field of the swapper address space.
281   */
282  typedef struct {
283  	unsigned long val;
284  } swp_entry_t;
285  
286  /**
287   * struct folio - Represents a contiguous set of bytes.
288   * @flags: Identical to the page flags.
289   * @lru: Least Recently Used list; tracks how recently this folio was used.
290   * @mlock_count: Number of times this folio has been pinned by mlock().
291   * @mapping: The file this page belongs to, or refers to the anon_vma for
292   *    anonymous memory.
293   * @index: Offset within the file, in units of pages.  For anonymous memory,
294   *    this is the index from the beginning of the mmap.
295   * @private: Filesystem per-folio data (see folio_attach_private()).
296   * @swap: Used for swp_entry_t if folio_test_swapcache().
297   * @_mapcount: Do not access this member directly.  Use folio_mapcount() to
298   *    find out how many times this folio is mapped by userspace.
299   * @_refcount: Do not access this member directly.  Use folio_ref_count()
300   *    to find how many references there are to this folio.
301   * @memcg_data: Memory Control Group data.
302   * @virtual: Virtual address in the kernel direct map.
303   * @_last_cpupid: IDs of last CPU and last process that accessed the folio.
304   * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
305   * @_large_mapcount: Do not use directly, call folio_mapcount().
306   * @_nr_pages_mapped: Do not use outside of rmap and debug code.
307   * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
308   * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
309   * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
310   * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
311   * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
312   * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
313   * @_deferred_list: Folios to be split under memory pressure.
314   * @_unused_slab_obj_exts: Placeholder to match obj_exts in struct slab.
315   *
316   * A folio is a physically, virtually and logically contiguous set
317   * of bytes.  It is a power-of-two in size, and it is aligned to that
318   * same power-of-two.  It is at least as large as %PAGE_SIZE.  If it is
319   * in the page cache, it is at a file offset which is a multiple of that
320   * power-of-two.  It may be mapped into userspace at an address which is
321   * at an arbitrary page offset, but its kernel virtual address is aligned
322   * to its size.
323   */
324  struct folio {
325  	/* private: don't document the anon union */
326  	union {
327  		struct {
328  	/* public: */
329  			unsigned long flags;
330  			union {
331  				struct list_head lru;
332  	/* private: avoid cluttering the output */
333  				struct {
334  					void *__filler;
335  	/* public: */
336  					unsigned int mlock_count;
337  	/* private: */
338  				};
339  	/* public: */
340  			};
341  			struct address_space *mapping;
342  			pgoff_t index;
343  			union {
344  				void *private;
345  				swp_entry_t swap;
346  			};
347  			atomic_t _mapcount;
348  			atomic_t _refcount;
349  #ifdef CONFIG_MEMCG
350  			unsigned long memcg_data;
351  #elif defined(CONFIG_SLAB_OBJ_EXT)
352  			unsigned long _unused_slab_obj_exts;
353  #endif
354  #if defined(WANT_PAGE_VIRTUAL)
355  			void *virtual;
356  #endif
357  #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
358  			int _last_cpupid;
359  #endif
360  	/* private: the union with struct page is transitional */
361  		};
362  		struct page page;
363  	};
364  	union {
365  		struct {
366  			unsigned long _flags_1;
367  			unsigned long _head_1;
368  	/* public: */
369  			atomic_t _large_mapcount;
370  			atomic_t _entire_mapcount;
371  			atomic_t _nr_pages_mapped;
372  			atomic_t _pincount;
373  #ifdef CONFIG_64BIT
374  			unsigned int _folio_nr_pages;
375  #endif
376  	/* private: the union with struct page is transitional */
377  		};
378  		struct page __page_1;
379  	};
380  	union {
381  		struct {
382  			unsigned long _flags_2;
383  			unsigned long _head_2;
384  	/* public: */
385  			void *_hugetlb_subpool;
386  			void *_hugetlb_cgroup;
387  			void *_hugetlb_cgroup_rsvd;
388  			void *_hugetlb_hwpoison;
389  	/* private: the union with struct page is transitional */
390  		};
391  		struct {
392  			unsigned long _flags_2a;
393  			unsigned long _head_2a;
394  	/* public: */
395  			struct list_head _deferred_list;
396  	/* private: the union with struct page is transitional */
397  		};
398  		struct page __page_2;
399  	};
400  };
401  
402  #define FOLIO_MATCH(pg, fl)						\
403  	static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
404  FOLIO_MATCH(flags, flags);
405  FOLIO_MATCH(lru, lru);
406  FOLIO_MATCH(mapping, mapping);
407  FOLIO_MATCH(compound_head, lru);
408  FOLIO_MATCH(index, index);
409  FOLIO_MATCH(private, private);
410  FOLIO_MATCH(_mapcount, _mapcount);
411  FOLIO_MATCH(_refcount, _refcount);
412  #ifdef CONFIG_MEMCG
413  FOLIO_MATCH(memcg_data, memcg_data);
414  #endif
415  #if defined(WANT_PAGE_VIRTUAL)
416  FOLIO_MATCH(virtual, virtual);
417  #endif
418  #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
419  FOLIO_MATCH(_last_cpupid, _last_cpupid);
420  #endif
421  #undef FOLIO_MATCH
422  #define FOLIO_MATCH(pg, fl)						\
423  	static_assert(offsetof(struct folio, fl) ==			\
424  			offsetof(struct page, pg) + sizeof(struct page))
425  FOLIO_MATCH(flags, _flags_1);
426  FOLIO_MATCH(compound_head, _head_1);
427  #undef FOLIO_MATCH
428  #define FOLIO_MATCH(pg, fl)						\
429  	static_assert(offsetof(struct folio, fl) ==			\
430  			offsetof(struct page, pg) + 2 * sizeof(struct page))
431  FOLIO_MATCH(flags, _flags_2);
432  FOLIO_MATCH(compound_head, _head_2);
433  FOLIO_MATCH(flags, _flags_2a);
434  FOLIO_MATCH(compound_head, _head_2a);
435  #undef FOLIO_MATCH
436  
437  /**
438   * struct ptdesc -    Memory descriptor for page tables.
439   * @__page_flags:     Same as page flags. Powerpc only.
440   * @pt_rcu_head:      For freeing page table pages.
441   * @pt_list:          List of used page tables. Used for s390 and x86.
442   * @_pt_pad_1:        Padding that aliases with page's compound head.
443   * @pmd_huge_pte:     Protected by ptdesc->ptl, used for THPs.
444   * @__page_mapping:   Aliases with page->mapping. Unused for page tables.
445   * @pt_index:         Used for s390 gmap.
446   * @pt_mm:            Used for x86 pgds.
447   * @pt_frag_refcount: For fragmented page table tracking. Powerpc only.
448   * @_pt_pad_2:        Padding to ensure proper alignment.
449   * @ptl:              Lock for the page table.
450   * @__page_type:      Same as page->page_type. Unused for page tables.
451   * @__page_refcount:  Same as page refcount.
452   * @pt_memcg_data:    Memcg data. Tracked for page tables here.
453   *
454   * This struct overlays struct page for now. Do not modify without a good
455   * understanding of the issues.
456   */
457  struct ptdesc {
458  	unsigned long __page_flags;
459  
460  	union {
461  		struct rcu_head pt_rcu_head;
462  		struct list_head pt_list;
463  		struct {
464  			unsigned long _pt_pad_1;
465  			pgtable_t pmd_huge_pte;
466  		};
467  	};
468  	unsigned long __page_mapping;
469  
470  	union {
471  		pgoff_t pt_index;
472  		struct mm_struct *pt_mm;
473  		atomic_t pt_frag_refcount;
474  	};
475  
476  	union {
477  		unsigned long _pt_pad_2;
478  #if ALLOC_SPLIT_PTLOCKS
479  		spinlock_t *ptl;
480  #else
481  		spinlock_t ptl;
482  #endif
483  	};
484  	unsigned int __page_type;
485  	atomic_t __page_refcount;
486  #ifdef CONFIG_MEMCG
487  	unsigned long pt_memcg_data;
488  #endif
489  };
490  
491  #define TABLE_MATCH(pg, pt)						\
492  	static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
493  TABLE_MATCH(flags, __page_flags);
494  TABLE_MATCH(compound_head, pt_list);
495  TABLE_MATCH(compound_head, _pt_pad_1);
496  TABLE_MATCH(mapping, __page_mapping);
497  TABLE_MATCH(index, pt_index);
498  TABLE_MATCH(rcu_head, pt_rcu_head);
499  TABLE_MATCH(page_type, __page_type);
500  TABLE_MATCH(_refcount, __page_refcount);
501  #ifdef CONFIG_MEMCG
502  TABLE_MATCH(memcg_data, pt_memcg_data);
503  #endif
504  #undef TABLE_MATCH
505  static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
506  
507  #define ptdesc_page(pt)			(_Generic((pt),			\
508  	const struct ptdesc *:		(const struct page *)(pt),	\
509  	struct ptdesc *:		(struct page *)(pt)))
510  
511  #define ptdesc_folio(pt)		(_Generic((pt),			\
512  	const struct ptdesc *:		(const struct folio *)(pt),	\
513  	struct ptdesc *:		(struct folio *)(pt)))
514  
515  #define page_ptdesc(p)			(_Generic((p),			\
516  	const struct page *:		(const struct ptdesc *)(p),	\
517  	struct page *:			(struct ptdesc *)(p)))
518  
519  /*
520   * Used for sizing the vmemmap region on some architectures
521   */
522  #define STRUCT_PAGE_MAX_SHIFT	(order_base_2(sizeof(struct page)))
523  
524  #define PAGE_FRAG_CACHE_MAX_SIZE	__ALIGN_MASK(32768, ~PAGE_MASK)
525  #define PAGE_FRAG_CACHE_MAX_ORDER	get_order(PAGE_FRAG_CACHE_MAX_SIZE)
526  
527  /*
528   * page_private can be used on tail pages.  However, PagePrivate is only
529   * checked by the VM on the head page.  So page_private on the tail pages
530   * should be used for data that's ancillary to the head page (eg attaching
531   * buffer heads to tail pages after attaching buffer heads to the head page)
532   */
533  #define page_private(page)		((page)->private)
534  
set_page_private(struct page * page,unsigned long private)535  static inline void set_page_private(struct page *page, unsigned long private)
536  {
537  	page->private = private;
538  }
539  
folio_get_private(struct folio * folio)540  static inline void *folio_get_private(struct folio *folio)
541  {
542  	return folio->private;
543  }
544  
545  struct page_frag_cache {
546  	void * va;
547  #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
548  	__u16 offset;
549  	__u16 size;
550  #else
551  	__u32 offset;
552  #endif
553  	/* we maintain a pagecount bias, so that we dont dirty cache line
554  	 * containing page->_refcount every time we allocate a fragment.
555  	 */
556  	unsigned int		pagecnt_bias;
557  	bool pfmemalloc;
558  };
559  
560  typedef unsigned long vm_flags_t;
561  
562  /*
563   * A region containing a mapping of a non-memory backed file under NOMMU
564   * conditions.  These are held in a global tree and are pinned by the VMAs that
565   * map parts of them.
566   */
567  struct vm_region {
568  	struct rb_node	vm_rb;		/* link in global region tree */
569  	vm_flags_t	vm_flags;	/* VMA vm_flags */
570  	unsigned long	vm_start;	/* start address of region */
571  	unsigned long	vm_end;		/* region initialised to here */
572  	unsigned long	vm_top;		/* region allocated to here */
573  	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
574  	struct file	*vm_file;	/* the backing file or NULL */
575  
576  	int		vm_usage;	/* region usage count (access under nommu_region_sem) */
577  	bool		vm_icache_flushed : 1; /* true if the icache has been flushed for
578  						* this region */
579  };
580  
581  #ifdef CONFIG_USERFAULTFD
582  #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
583  struct vm_userfaultfd_ctx {
584  	struct userfaultfd_ctx *ctx;
585  };
586  #else /* CONFIG_USERFAULTFD */
587  #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
588  struct vm_userfaultfd_ctx {};
589  #endif /* CONFIG_USERFAULTFD */
590  
591  struct anon_vma_name {
592  	struct kref kref;
593  	/* The name needs to be at the end because it is dynamically sized. */
594  	char name[];
595  };
596  
597  #ifdef CONFIG_ANON_VMA_NAME
598  /*
599   * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
600   * either keep holding the lock while using the returned pointer or it should
601   * raise anon_vma_name refcount before releasing the lock.
602   */
603  struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
604  struct anon_vma_name *anon_vma_name_alloc(const char *name);
605  void anon_vma_name_free(struct kref *kref);
606  #else /* CONFIG_ANON_VMA_NAME */
anon_vma_name(struct vm_area_struct * vma)607  static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
608  {
609  	return NULL;
610  }
611  
anon_vma_name_alloc(const char * name)612  static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
613  {
614  	return NULL;
615  }
616  #endif
617  
618  struct vma_lock {
619  	struct rw_semaphore lock;
620  };
621  
622  struct vma_numab_state {
623  	/*
624  	 * Initialised as time in 'jiffies' after which VMA
625  	 * should be scanned.  Delays first scan of new VMA by at
626  	 * least sysctl_numa_balancing_scan_delay:
627  	 */
628  	unsigned long next_scan;
629  
630  	/*
631  	 * Time in jiffies when pids_active[] is reset to
632  	 * detect phase change behaviour:
633  	 */
634  	unsigned long pids_active_reset;
635  
636  	/*
637  	 * Approximate tracking of PIDs that trapped a NUMA hinting
638  	 * fault. May produce false positives due to hash collisions.
639  	 *
640  	 *   [0] Previous PID tracking
641  	 *   [1] Current PID tracking
642  	 *
643  	 * Window moves after next_pid_reset has expired approximately
644  	 * every VMA_PID_RESET_PERIOD jiffies:
645  	 */
646  	unsigned long pids_active[2];
647  
648  	/* MM scan sequence ID when scan first started after VMA creation */
649  	int start_scan_seq;
650  
651  	/*
652  	 * MM scan sequence ID when the VMA was last completely scanned.
653  	 * A VMA is not eligible for scanning if prev_scan_seq == numa_scan_seq
654  	 */
655  	int prev_scan_seq;
656  };
657  
658  /*
659   * This struct describes a virtual memory area. There is one of these
660   * per VM-area/task. A VM area is any part of the process virtual memory
661   * space that has a special rule for the page-fault handlers (ie a shared
662   * library, the executable area etc).
663   *
664   * Only explicitly marked struct members may be accessed by RCU readers before
665   * getting a stable reference.
666   */
667  struct vm_area_struct {
668  	/* The first cache line has the info for VMA tree walking. */
669  
670  	union {
671  		struct {
672  			/* VMA covers [vm_start; vm_end) addresses within mm */
673  			unsigned long vm_start;
674  			unsigned long vm_end;
675  		};
676  #ifdef CONFIG_PER_VMA_LOCK
677  		struct rcu_head vm_rcu;	/* Used for deferred freeing. */
678  #endif
679  	};
680  
681  	/*
682  	 * The address space we belong to.
683  	 * Unstable RCU readers are allowed to read this.
684  	 */
685  	struct mm_struct *vm_mm;
686  	pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
687  
688  	/*
689  	 * Flags, see mm.h.
690  	 * To modify use vm_flags_{init|reset|set|clear|mod} functions.
691  	 */
692  	union {
693  		const vm_flags_t vm_flags;
694  		vm_flags_t __private __vm_flags;
695  	};
696  
697  #ifdef CONFIG_PER_VMA_LOCK
698  	/*
699  	 * Flag to indicate areas detached from the mm->mm_mt tree.
700  	 * Unstable RCU readers are allowed to read this.
701  	 */
702  	bool detached;
703  
704  	/*
705  	 * Can only be written (using WRITE_ONCE()) while holding both:
706  	 *  - mmap_lock (in write mode)
707  	 *  - vm_lock->lock (in write mode)
708  	 * Can be read reliably while holding one of:
709  	 *  - mmap_lock (in read or write mode)
710  	 *  - vm_lock->lock (in read or write mode)
711  	 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout
712  	 * while holding nothing (except RCU to keep the VMA struct allocated).
713  	 *
714  	 * This sequence counter is explicitly allowed to overflow; sequence
715  	 * counter reuse can only lead to occasional unnecessary use of the
716  	 * slowpath.
717  	 */
718  	int vm_lock_seq;
719  	/* Unstable RCU readers are allowed to read this. */
720  	struct vma_lock *vm_lock;
721  #endif
722  
723  	/*
724  	 * For areas with an address space and backing store,
725  	 * linkage into the address_space->i_mmap interval tree.
726  	 *
727  	 */
728  	struct {
729  		struct rb_node rb;
730  		unsigned long rb_subtree_last;
731  	} shared;
732  
733  	/*
734  	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
735  	 * list, after a COW of one of the file pages.	A MAP_SHARED vma
736  	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
737  	 * or brk vma (with NULL file) can only be in an anon_vma list.
738  	 */
739  	struct list_head anon_vma_chain; /* Serialized by mmap_lock &
740  					  * page_table_lock */
741  	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */
742  
743  	/* Function pointers to deal with this struct. */
744  	const struct vm_operations_struct *vm_ops;
745  
746  	/* Information about our backing store: */
747  	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
748  					   units */
749  	struct file * vm_file;		/* File we map to (can be NULL). */
750  	void * vm_private_data;		/* was vm_pte (shared mem) */
751  
752  #ifdef CONFIG_ANON_VMA_NAME
753  	/*
754  	 * For private and shared anonymous mappings, a pointer to a null
755  	 * terminated string containing the name given to the vma, or NULL if
756  	 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
757  	 */
758  	struct anon_vma_name *anon_name;
759  #endif
760  #ifdef CONFIG_SWAP
761  	atomic_long_t swap_readahead_info;
762  #endif
763  #ifndef CONFIG_MMU
764  	struct vm_region *vm_region;	/* NOMMU mapping region */
765  #endif
766  #ifdef CONFIG_NUMA
767  	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
768  #endif
769  #ifdef CONFIG_NUMA_BALANCING
770  	struct vma_numab_state *numab_state;	/* NUMA Balancing state */
771  #endif
772  	struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
773  } __randomize_layout;
774  
775  #ifdef CONFIG_NUMA
776  #define vma_policy(vma) ((vma)->vm_policy)
777  #else
778  #define vma_policy(vma) NULL
779  #endif
780  
781  #ifdef CONFIG_SCHED_MM_CID
782  struct mm_cid {
783  	u64 time;
784  	int cid;
785  };
786  #endif
787  
788  struct kioctx_table;
789  struct iommu_mm_data;
790  struct mm_struct {
791  	struct {
792  		/*
793  		 * Fields which are often written to are placed in a separate
794  		 * cache line.
795  		 */
796  		struct {
797  			/**
798  			 * @mm_count: The number of references to &struct
799  			 * mm_struct (@mm_users count as 1).
800  			 *
801  			 * Use mmgrab()/mmdrop() to modify. When this drops to
802  			 * 0, the &struct mm_struct is freed.
803  			 */
804  			atomic_t mm_count;
805  		} ____cacheline_aligned_in_smp;
806  
807  		struct maple_tree mm_mt;
808  
809  		unsigned long mmap_base;	/* base of mmap area */
810  		unsigned long mmap_legacy_base;	/* base of mmap area in bottom-up allocations */
811  #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES
812  		/* Base addresses for compatible mmap() */
813  		unsigned long mmap_compat_base;
814  		unsigned long mmap_compat_legacy_base;
815  #endif
816  		unsigned long task_size;	/* size of task vm space */
817  		pgd_t * pgd;
818  
819  #ifdef CONFIG_MEMBARRIER
820  		/**
821  		 * @membarrier_state: Flags controlling membarrier behavior.
822  		 *
823  		 * This field is close to @pgd to hopefully fit in the same
824  		 * cache-line, which needs to be touched by switch_mm().
825  		 */
826  		atomic_t membarrier_state;
827  #endif
828  
829  		/**
830  		 * @mm_users: The number of users including userspace.
831  		 *
832  		 * Use mmget()/mmget_not_zero()/mmput() to modify. When this
833  		 * drops to 0 (i.e. when the task exits and there are no other
834  		 * temporary reference holders), we also release a reference on
835  		 * @mm_count (which may then free the &struct mm_struct if
836  		 * @mm_count also drops to 0).
837  		 */
838  		atomic_t mm_users;
839  
840  #ifdef CONFIG_SCHED_MM_CID
841  		/**
842  		 * @pcpu_cid: Per-cpu current cid.
843  		 *
844  		 * Keep track of the currently allocated mm_cid for each cpu.
845  		 * The per-cpu mm_cid values are serialized by their respective
846  		 * runqueue locks.
847  		 */
848  		struct mm_cid __percpu *pcpu_cid;
849  		/*
850  		 * @mm_cid_next_scan: Next mm_cid scan (in jiffies).
851  		 *
852  		 * When the next mm_cid scan is due (in jiffies).
853  		 */
854  		unsigned long mm_cid_next_scan;
855  #endif
856  #ifdef CONFIG_MMU
857  		atomic_long_t pgtables_bytes;	/* size of all page tables */
858  #endif
859  		int map_count;			/* number of VMAs */
860  
861  		spinlock_t page_table_lock; /* Protects page tables and some
862  					     * counters
863  					     */
864  		/*
865  		 * With some kernel config, the current mmap_lock's offset
866  		 * inside 'mm_struct' is at 0x120, which is very optimal, as
867  		 * its two hot fields 'count' and 'owner' sit in 2 different
868  		 * cachelines,  and when mmap_lock is highly contended, both
869  		 * of the 2 fields will be accessed frequently, current layout
870  		 * will help to reduce cache bouncing.
871  		 *
872  		 * So please be careful with adding new fields before
873  		 * mmap_lock, which can easily push the 2 fields into one
874  		 * cacheline.
875  		 */
876  		struct rw_semaphore mmap_lock;
877  
878  		struct list_head mmlist; /* List of maybe swapped mm's.	These
879  					  * are globally strung together off
880  					  * init_mm.mmlist, and are protected
881  					  * by mmlist_lock
882  					  */
883  #ifdef CONFIG_PER_VMA_LOCK
884  		/*
885  		 * This field has lock-like semantics, meaning it is sometimes
886  		 * accessed with ACQUIRE/RELEASE semantics.
887  		 * Roughly speaking, incrementing the sequence number is
888  		 * equivalent to releasing locks on VMAs; reading the sequence
889  		 * number can be part of taking a read lock on a VMA.
890  		 *
891  		 * Can be modified under write mmap_lock using RELEASE
892  		 * semantics.
893  		 * Can be read with no other protection when holding write
894  		 * mmap_lock.
895  		 * Can be read with ACQUIRE semantics if not holding write
896  		 * mmap_lock.
897  		 */
898  		int mm_lock_seq;
899  #endif
900  
901  
902  		unsigned long hiwater_rss; /* High-watermark of RSS usage */
903  		unsigned long hiwater_vm;  /* High-water virtual memory usage */
904  
905  		unsigned long total_vm;	   /* Total pages mapped */
906  		unsigned long locked_vm;   /* Pages that have PG_mlocked set */
907  		atomic64_t    pinned_vm;   /* Refcount permanently increased */
908  		unsigned long data_vm;	   /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
909  		unsigned long exec_vm;	   /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
910  		unsigned long stack_vm;	   /* VM_STACK */
911  		unsigned long def_flags;
912  
913  		/**
914  		 * @write_protect_seq: Locked when any thread is write
915  		 * protecting pages mapped by this mm to enforce a later COW,
916  		 * for instance during page table copying for fork().
917  		 */
918  		seqcount_t write_protect_seq;
919  
920  		spinlock_t arg_lock; /* protect the below fields */
921  
922  		unsigned long start_code, end_code, start_data, end_data;
923  		unsigned long start_brk, brk, start_stack;
924  		unsigned long arg_start, arg_end, env_start, env_end;
925  
926  		unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
927  
928  		struct percpu_counter rss_stat[NR_MM_COUNTERS];
929  
930  		struct linux_binfmt *binfmt;
931  
932  		/* Architecture-specific MM context */
933  		mm_context_t context;
934  
935  		unsigned long flags; /* Must use atomic bitops to access */
936  
937  #ifdef CONFIG_AIO
938  		spinlock_t			ioctx_lock;
939  		struct kioctx_table __rcu	*ioctx_table;
940  #endif
941  #ifdef CONFIG_MEMCG
942  		/*
943  		 * "owner" points to a task that is regarded as the canonical
944  		 * user/owner of this mm. All of the following must be true in
945  		 * order for it to be changed:
946  		 *
947  		 * current == mm->owner
948  		 * current->mm != mm
949  		 * new_owner->mm == mm
950  		 * new_owner->alloc_lock is held
951  		 */
952  		struct task_struct __rcu *owner;
953  #endif
954  		struct user_namespace *user_ns;
955  
956  		/* store ref to file /proc/<pid>/exe symlink points to */
957  		struct file __rcu *exe_file;
958  #ifdef CONFIG_MMU_NOTIFIER
959  		struct mmu_notifier_subscriptions *notifier_subscriptions;
960  #endif
961  #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)
962  		pgtable_t pmd_huge_pte; /* protected by page_table_lock */
963  #endif
964  #ifdef CONFIG_NUMA_BALANCING
965  		/*
966  		 * numa_next_scan is the next time that PTEs will be remapped
967  		 * PROT_NONE to trigger NUMA hinting faults; such faults gather
968  		 * statistics and migrate pages to new nodes if necessary.
969  		 */
970  		unsigned long numa_next_scan;
971  
972  		/* Restart point for scanning and remapping PTEs. */
973  		unsigned long numa_scan_offset;
974  
975  		/* numa_scan_seq prevents two threads remapping PTEs. */
976  		int numa_scan_seq;
977  #endif
978  		/*
979  		 * An operation with batched TLB flushing is going on. Anything
980  		 * that can move process memory needs to flush the TLB when
981  		 * moving a PROT_NONE mapped page.
982  		 */
983  		atomic_t tlb_flush_pending;
984  #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
985  		/* See flush_tlb_batched_pending() */
986  		atomic_t tlb_flush_batched;
987  #endif
988  		struct uprobes_state uprobes_state;
989  #ifdef CONFIG_PREEMPT_RT
990  		struct rcu_head delayed_drop;
991  #endif
992  #ifdef CONFIG_HUGETLB_PAGE
993  		atomic_long_t hugetlb_usage;
994  #endif
995  		struct work_struct async_put_work;
996  
997  #ifdef CONFIG_IOMMU_MM_DATA
998  		struct iommu_mm_data *iommu_mm;
999  #endif
1000  #ifdef CONFIG_KSM
1001  		/*
1002  		 * Represent how many pages of this process are involved in KSM
1003  		 * merging (not including ksm_zero_pages).
1004  		 */
1005  		unsigned long ksm_merging_pages;
1006  		/*
1007  		 * Represent how many pages are checked for ksm merging
1008  		 * including merged and not merged.
1009  		 */
1010  		unsigned long ksm_rmap_items;
1011  		/*
1012  		 * Represent how many empty pages are merged with kernel zero
1013  		 * pages when enabling KSM use_zero_pages.
1014  		 */
1015  		atomic_long_t ksm_zero_pages;
1016  #endif /* CONFIG_KSM */
1017  #ifdef CONFIG_LRU_GEN_WALKS_MMU
1018  		struct {
1019  			/* this mm_struct is on lru_gen_mm_list */
1020  			struct list_head list;
1021  			/*
1022  			 * Set when switching to this mm_struct, as a hint of
1023  			 * whether it has been used since the last time per-node
1024  			 * page table walkers cleared the corresponding bits.
1025  			 */
1026  			unsigned long bitmap;
1027  #ifdef CONFIG_MEMCG
1028  			/* points to the memcg of "owner" above */
1029  			struct mem_cgroup *memcg;
1030  #endif
1031  		} lru_gen;
1032  #endif /* CONFIG_LRU_GEN_WALKS_MMU */
1033  	} __randomize_layout;
1034  
1035  	/*
1036  	 * The mm_cpumask needs to be at the end of mm_struct, because it
1037  	 * is dynamically sized based on nr_cpu_ids.
1038  	 */
1039  	unsigned long cpu_bitmap[];
1040  };
1041  
1042  #define MM_MT_FLAGS	(MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
1043  			 MT_FLAGS_USE_RCU)
1044  extern struct mm_struct init_mm;
1045  
1046  /* Pointer magic because the dynamic array size confuses some compilers. */
mm_init_cpumask(struct mm_struct * mm)1047  static inline void mm_init_cpumask(struct mm_struct *mm)
1048  {
1049  	unsigned long cpu_bitmap = (unsigned long)mm;
1050  
1051  	cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap);
1052  	cpumask_clear((struct cpumask *)cpu_bitmap);
1053  }
1054  
1055  /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
mm_cpumask(struct mm_struct * mm)1056  static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
1057  {
1058  	return (struct cpumask *)&mm->cpu_bitmap;
1059  }
1060  
1061  #ifdef CONFIG_LRU_GEN
1062  
1063  struct lru_gen_mm_list {
1064  	/* mm_struct list for page table walkers */
1065  	struct list_head fifo;
1066  	/* protects the list above */
1067  	spinlock_t lock;
1068  };
1069  
1070  #endif /* CONFIG_LRU_GEN */
1071  
1072  #ifdef CONFIG_LRU_GEN_WALKS_MMU
1073  
1074  void lru_gen_add_mm(struct mm_struct *mm);
1075  void lru_gen_del_mm(struct mm_struct *mm);
1076  void lru_gen_migrate_mm(struct mm_struct *mm);
1077  
lru_gen_init_mm(struct mm_struct * mm)1078  static inline void lru_gen_init_mm(struct mm_struct *mm)
1079  {
1080  	INIT_LIST_HEAD(&mm->lru_gen.list);
1081  	mm->lru_gen.bitmap = 0;
1082  #ifdef CONFIG_MEMCG
1083  	mm->lru_gen.memcg = NULL;
1084  #endif
1085  }
1086  
lru_gen_use_mm(struct mm_struct * mm)1087  static inline void lru_gen_use_mm(struct mm_struct *mm)
1088  {
1089  	/*
1090  	 * When the bitmap is set, page reclaim knows this mm_struct has been
1091  	 * used since the last time it cleared the bitmap. So it might be worth
1092  	 * walking the page tables of this mm_struct to clear the accessed bit.
1093  	 */
1094  	WRITE_ONCE(mm->lru_gen.bitmap, -1);
1095  }
1096  
1097  #else /* !CONFIG_LRU_GEN_WALKS_MMU */
1098  
lru_gen_add_mm(struct mm_struct * mm)1099  static inline void lru_gen_add_mm(struct mm_struct *mm)
1100  {
1101  }
1102  
lru_gen_del_mm(struct mm_struct * mm)1103  static inline void lru_gen_del_mm(struct mm_struct *mm)
1104  {
1105  }
1106  
lru_gen_migrate_mm(struct mm_struct * mm)1107  static inline void lru_gen_migrate_mm(struct mm_struct *mm)
1108  {
1109  }
1110  
lru_gen_init_mm(struct mm_struct * mm)1111  static inline void lru_gen_init_mm(struct mm_struct *mm)
1112  {
1113  }
1114  
lru_gen_use_mm(struct mm_struct * mm)1115  static inline void lru_gen_use_mm(struct mm_struct *mm)
1116  {
1117  }
1118  
1119  #endif /* CONFIG_LRU_GEN_WALKS_MMU */
1120  
1121  struct vma_iterator {
1122  	struct ma_state mas;
1123  };
1124  
1125  #define VMA_ITERATOR(name, __mm, __addr)				\
1126  	struct vma_iterator name = {					\
1127  		.mas = {						\
1128  			.tree = &(__mm)->mm_mt,				\
1129  			.index = __addr,				\
1130  			.node = NULL,					\
1131  			.status = ma_start,				\
1132  		},							\
1133  	}
1134  
vma_iter_init(struct vma_iterator * vmi,struct mm_struct * mm,unsigned long addr)1135  static inline void vma_iter_init(struct vma_iterator *vmi,
1136  		struct mm_struct *mm, unsigned long addr)
1137  {
1138  	mas_init(&vmi->mas, &mm->mm_mt, addr);
1139  }
1140  
1141  #ifdef CONFIG_SCHED_MM_CID
1142  
1143  enum mm_cid_state {
1144  	MM_CID_UNSET = -1U,		/* Unset state has lazy_put flag set. */
1145  	MM_CID_LAZY_PUT = (1U << 31),
1146  };
1147  
mm_cid_is_unset(int cid)1148  static inline bool mm_cid_is_unset(int cid)
1149  {
1150  	return cid == MM_CID_UNSET;
1151  }
1152  
mm_cid_is_lazy_put(int cid)1153  static inline bool mm_cid_is_lazy_put(int cid)
1154  {
1155  	return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT);
1156  }
1157  
mm_cid_is_valid(int cid)1158  static inline bool mm_cid_is_valid(int cid)
1159  {
1160  	return !(cid & MM_CID_LAZY_PUT);
1161  }
1162  
mm_cid_set_lazy_put(int cid)1163  static inline int mm_cid_set_lazy_put(int cid)
1164  {
1165  	return cid | MM_CID_LAZY_PUT;
1166  }
1167  
mm_cid_clear_lazy_put(int cid)1168  static inline int mm_cid_clear_lazy_put(int cid)
1169  {
1170  	return cid & ~MM_CID_LAZY_PUT;
1171  }
1172  
1173  /* Accessor for struct mm_struct's cidmask. */
mm_cidmask(struct mm_struct * mm)1174  static inline cpumask_t *mm_cidmask(struct mm_struct *mm)
1175  {
1176  	unsigned long cid_bitmap = (unsigned long)mm;
1177  
1178  	cid_bitmap += offsetof(struct mm_struct, cpu_bitmap);
1179  	/* Skip cpu_bitmap */
1180  	cid_bitmap += cpumask_size();
1181  	return (struct cpumask *)cid_bitmap;
1182  }
1183  
mm_init_cid(struct mm_struct * mm)1184  static inline void mm_init_cid(struct mm_struct *mm)
1185  {
1186  	int i;
1187  
1188  	for_each_possible_cpu(i) {
1189  		struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i);
1190  
1191  		pcpu_cid->cid = MM_CID_UNSET;
1192  		pcpu_cid->time = 0;
1193  	}
1194  	cpumask_clear(mm_cidmask(mm));
1195  }
1196  
mm_alloc_cid_noprof(struct mm_struct * mm)1197  static inline int mm_alloc_cid_noprof(struct mm_struct *mm)
1198  {
1199  	mm->pcpu_cid = alloc_percpu_noprof(struct mm_cid);
1200  	if (!mm->pcpu_cid)
1201  		return -ENOMEM;
1202  	mm_init_cid(mm);
1203  	return 0;
1204  }
1205  #define mm_alloc_cid(...)	alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__))
1206  
mm_destroy_cid(struct mm_struct * mm)1207  static inline void mm_destroy_cid(struct mm_struct *mm)
1208  {
1209  	free_percpu(mm->pcpu_cid);
1210  	mm->pcpu_cid = NULL;
1211  }
1212  
mm_cid_size(void)1213  static inline unsigned int mm_cid_size(void)
1214  {
1215  	return cpumask_size();
1216  }
1217  #else /* CONFIG_SCHED_MM_CID */
mm_init_cid(struct mm_struct * mm)1218  static inline void mm_init_cid(struct mm_struct *mm) { }
mm_alloc_cid(struct mm_struct * mm)1219  static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; }
mm_destroy_cid(struct mm_struct * mm)1220  static inline void mm_destroy_cid(struct mm_struct *mm) { }
mm_cid_size(void)1221  static inline unsigned int mm_cid_size(void)
1222  {
1223  	return 0;
1224  }
1225  #endif /* CONFIG_SCHED_MM_CID */
1226  
1227  struct mmu_gather;
1228  extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);
1229  extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);
1230  extern void tlb_finish_mmu(struct mmu_gather *tlb);
1231  
1232  struct vm_fault;
1233  
1234  /**
1235   * typedef vm_fault_t - Return type for page fault handlers.
1236   *
1237   * Page fault handlers return a bitmask of %VM_FAULT values.
1238   */
1239  typedef __bitwise unsigned int vm_fault_t;
1240  
1241  /**
1242   * enum vm_fault_reason - Page fault handlers return a bitmask of
1243   * these values to tell the core VM what happened when handling the
1244   * fault. Used to decide whether a process gets delivered SIGBUS or
1245   * just gets major/minor fault counters bumped up.
1246   *
1247   * @VM_FAULT_OOM:		Out Of Memory
1248   * @VM_FAULT_SIGBUS:		Bad access
1249   * @VM_FAULT_MAJOR:		Page read from storage
1250   * @VM_FAULT_HWPOISON:		Hit poisoned small page
1251   * @VM_FAULT_HWPOISON_LARGE:	Hit poisoned large page. Index encoded
1252   *				in upper bits
1253   * @VM_FAULT_SIGSEGV:		segmentation fault
1254   * @VM_FAULT_NOPAGE:		->fault installed the pte, not return page
1255   * @VM_FAULT_LOCKED:		->fault locked the returned page
1256   * @VM_FAULT_RETRY:		->fault blocked, must retry
1257   * @VM_FAULT_FALLBACK:		huge page fault failed, fall back to small
1258   * @VM_FAULT_DONE_COW:		->fault has fully handled COW
1259   * @VM_FAULT_NEEDDSYNC:		->fault did not modify page tables and needs
1260   *				fsync() to complete (for synchronous page faults
1261   *				in DAX)
1262   * @VM_FAULT_COMPLETED:		->fault completed, meanwhile mmap lock released
1263   * @VM_FAULT_HINDEX_MASK:	mask HINDEX value
1264   *
1265   */
1266  enum vm_fault_reason {
1267  	VM_FAULT_OOM            = (__force vm_fault_t)0x000001,
1268  	VM_FAULT_SIGBUS         = (__force vm_fault_t)0x000002,
1269  	VM_FAULT_MAJOR          = (__force vm_fault_t)0x000004,
1270  	VM_FAULT_HWPOISON       = (__force vm_fault_t)0x000010,
1271  	VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
1272  	VM_FAULT_SIGSEGV        = (__force vm_fault_t)0x000040,
1273  	VM_FAULT_NOPAGE         = (__force vm_fault_t)0x000100,
1274  	VM_FAULT_LOCKED         = (__force vm_fault_t)0x000200,
1275  	VM_FAULT_RETRY          = (__force vm_fault_t)0x000400,
1276  	VM_FAULT_FALLBACK       = (__force vm_fault_t)0x000800,
1277  	VM_FAULT_DONE_COW       = (__force vm_fault_t)0x001000,
1278  	VM_FAULT_NEEDDSYNC      = (__force vm_fault_t)0x002000,
1279  	VM_FAULT_COMPLETED      = (__force vm_fault_t)0x004000,
1280  	VM_FAULT_HINDEX_MASK    = (__force vm_fault_t)0x0f0000,
1281  };
1282  
1283  /* Encode hstate index for a hwpoisoned large page */
1284  #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16))
1285  #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf)
1286  
1287  #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS |	\
1288  			VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON |	\
1289  			VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
1290  
1291  #define VM_FAULT_RESULT_TRACE \
1292  	{ VM_FAULT_OOM,                 "OOM" },	\
1293  	{ VM_FAULT_SIGBUS,              "SIGBUS" },	\
1294  	{ VM_FAULT_MAJOR,               "MAJOR" },	\
1295  	{ VM_FAULT_HWPOISON,            "HWPOISON" },	\
1296  	{ VM_FAULT_HWPOISON_LARGE,      "HWPOISON_LARGE" },	\
1297  	{ VM_FAULT_SIGSEGV,             "SIGSEGV" },	\
1298  	{ VM_FAULT_NOPAGE,              "NOPAGE" },	\
1299  	{ VM_FAULT_LOCKED,              "LOCKED" },	\
1300  	{ VM_FAULT_RETRY,               "RETRY" },	\
1301  	{ VM_FAULT_FALLBACK,            "FALLBACK" },	\
1302  	{ VM_FAULT_DONE_COW,            "DONE_COW" },	\
1303  	{ VM_FAULT_NEEDDSYNC,           "NEEDDSYNC" },	\
1304  	{ VM_FAULT_COMPLETED,           "COMPLETED" }
1305  
1306  struct vm_special_mapping {
1307  	const char *name;	/* The name, e.g. "[vdso]". */
1308  
1309  	/*
1310  	 * If .fault is not provided, this points to a
1311  	 * NULL-terminated array of pages that back the special mapping.
1312  	 *
1313  	 * This must not be NULL unless .fault is provided.
1314  	 */
1315  	struct page **pages;
1316  
1317  	/*
1318  	 * If non-NULL, then this is called to resolve page faults
1319  	 * on the special mapping.  If used, .pages is not checked.
1320  	 */
1321  	vm_fault_t (*fault)(const struct vm_special_mapping *sm,
1322  				struct vm_area_struct *vma,
1323  				struct vm_fault *vmf);
1324  
1325  	int (*mremap)(const struct vm_special_mapping *sm,
1326  		     struct vm_area_struct *new_vma);
1327  
1328  	void (*close)(const struct vm_special_mapping *sm,
1329  		      struct vm_area_struct *vma);
1330  };
1331  
1332  enum tlb_flush_reason {
1333  	TLB_FLUSH_ON_TASK_SWITCH,
1334  	TLB_REMOTE_SHOOTDOWN,
1335  	TLB_LOCAL_SHOOTDOWN,
1336  	TLB_LOCAL_MM_SHOOTDOWN,
1337  	TLB_REMOTE_SEND_IPI,
1338  	NR_TLB_FLUSH_REASONS,
1339  };
1340  
1341  /**
1342   * enum fault_flag - Fault flag definitions.
1343   * @FAULT_FLAG_WRITE: Fault was a write fault.
1344   * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE.
1345   * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked.
1346   * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying.
1347   * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region.
1348   * @FAULT_FLAG_TRIED: The fault has been tried once.
1349   * @FAULT_FLAG_USER: The fault originated in userspace.
1350   * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
1351   * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
1352   * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
1353   * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a
1354   *                      COW mapping, making sure that an exclusive anon page is
1355   *                      mapped after the fault.
1356   * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached.
1357   *                        We should only access orig_pte if this flag set.
1358   * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock.
1359   *
1360   * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
1361   * whether we would allow page faults to retry by specifying these two
1362   * fault flags correctly.  Currently there can be three legal combinations:
1363   *
1364   * (a) ALLOW_RETRY and !TRIED:  this means the page fault allows retry, and
1365   *                              this is the first try
1366   *
1367   * (b) ALLOW_RETRY and TRIED:   this means the page fault allows retry, and
1368   *                              we've already tried at least once
1369   *
1370   * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry
1371   *
1372   * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never
1373   * be used.  Note that page faults can be allowed to retry for multiple times,
1374   * in which case we'll have an initial fault with flags (a) then later on
1375   * continuous faults with flags (b).  We should always try to detect pending
1376   * signals before a retry to make sure the continuous page faults can still be
1377   * interrupted if necessary.
1378   *
1379   * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal.
1380   * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when
1381   * applied to mappings that are not COW mappings.
1382   */
1383  enum fault_flag {
1384  	FAULT_FLAG_WRITE =		1 << 0,
1385  	FAULT_FLAG_MKWRITE =		1 << 1,
1386  	FAULT_FLAG_ALLOW_RETRY =	1 << 2,
1387  	FAULT_FLAG_RETRY_NOWAIT = 	1 << 3,
1388  	FAULT_FLAG_KILLABLE =		1 << 4,
1389  	FAULT_FLAG_TRIED = 		1 << 5,
1390  	FAULT_FLAG_USER =		1 << 6,
1391  	FAULT_FLAG_REMOTE =		1 << 7,
1392  	FAULT_FLAG_INSTRUCTION =	1 << 8,
1393  	FAULT_FLAG_INTERRUPTIBLE =	1 << 9,
1394  	FAULT_FLAG_UNSHARE =		1 << 10,
1395  	FAULT_FLAG_ORIG_PTE_VALID =	1 << 11,
1396  	FAULT_FLAG_VMA_LOCK =		1 << 12,
1397  };
1398  
1399  typedef unsigned int __bitwise zap_flags_t;
1400  
1401  /* Flags for clear_young_dirty_ptes(). */
1402  typedef int __bitwise cydp_t;
1403  
1404  /* Clear the access bit */
1405  #define CYDP_CLEAR_YOUNG		((__force cydp_t)BIT(0))
1406  
1407  /* Clear the dirty bit */
1408  #define CYDP_CLEAR_DIRTY		((__force cydp_t)BIT(1))
1409  
1410  /*
1411   * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
1412   * other. Here is what they mean, and how to use them:
1413   *
1414   *
1415   * FIXME: For pages which are part of a filesystem, mappings are subject to the
1416   * lifetime enforced by the filesystem and we need guarantees that longterm
1417   * users like RDMA and V4L2 only establish mappings which coordinate usage with
1418   * the filesystem.  Ideas for this coordination include revoking the longterm
1419   * pin, delaying writeback, bounce buffer page writeback, etc.  As FS DAX was
1420   * added after the problem with filesystems was found FS DAX VMAs are
1421   * specifically failed.  Filesystem pages are still subject to bugs and use of
1422   * FOLL_LONGTERM should be avoided on those pages.
1423   *
1424   * In the CMA case: long term pins in a CMA region would unnecessarily fragment
1425   * that region.  And so, CMA attempts to migrate the page before pinning, when
1426   * FOLL_LONGTERM is specified.
1427   *
1428   * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
1429   * but an additional pin counting system) will be invoked. This is intended for
1430   * anything that gets a page reference and then touches page data (for example,
1431   * Direct IO). This lets the filesystem know that some non-file-system entity is
1432   * potentially changing the pages' data. In contrast to FOLL_GET (whose pages
1433   * are released via put_page()), FOLL_PIN pages must be released, ultimately, by
1434   * a call to unpin_user_page().
1435   *
1436   * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
1437   * and separate refcounting mechanisms, however, and that means that each has
1438   * its own acquire and release mechanisms:
1439   *
1440   *     FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
1441   *
1442   *     FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
1443   *
1444   * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
1445   * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
1446   * calls applied to them, and that's perfectly OK. This is a constraint on the
1447   * callers, not on the pages.)
1448   *
1449   * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
1450   * directly by the caller. That's in order to help avoid mismatches when
1451   * releasing pages: get_user_pages*() pages must be released via put_page(),
1452   * while pin_user_pages*() pages must be released via unpin_user_page().
1453   *
1454   * Please see Documentation/core-api/pin_user_pages.rst for more information.
1455   */
1456  
1457  enum {
1458  	/* check pte is writable */
1459  	FOLL_WRITE = 1 << 0,
1460  	/* do get_page on page */
1461  	FOLL_GET = 1 << 1,
1462  	/* give error on hole if it would be zero */
1463  	FOLL_DUMP = 1 << 2,
1464  	/* get_user_pages read/write w/o permission */
1465  	FOLL_FORCE = 1 << 3,
1466  	/*
1467  	 * if a disk transfer is needed, start the IO and return without waiting
1468  	 * upon it
1469  	 */
1470  	FOLL_NOWAIT = 1 << 4,
1471  	/* do not fault in pages */
1472  	FOLL_NOFAULT = 1 << 5,
1473  	/* check page is hwpoisoned */
1474  	FOLL_HWPOISON = 1 << 6,
1475  	/* don't do file mappings */
1476  	FOLL_ANON = 1 << 7,
1477  	/*
1478  	 * FOLL_LONGTERM indicates that the page will be held for an indefinite
1479  	 * time period _often_ under userspace control.  This is in contrast to
1480  	 * iov_iter_get_pages(), whose usages are transient.
1481  	 */
1482  	FOLL_LONGTERM = 1 << 8,
1483  	/* split huge pmd before returning */
1484  	FOLL_SPLIT_PMD = 1 << 9,
1485  	/* allow returning PCI P2PDMA pages */
1486  	FOLL_PCI_P2PDMA = 1 << 10,
1487  	/* allow interrupts from generic signals */
1488  	FOLL_INTERRUPTIBLE = 1 << 11,
1489  	/*
1490  	 * Always honor (trigger) NUMA hinting faults.
1491  	 *
1492  	 * FOLL_WRITE implicitly honors NUMA hinting faults because a
1493  	 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE
1494  	 * apply). get_user_pages_fast_only() always implicitly honors NUMA
1495  	 * hinting faults.
1496  	 */
1497  	FOLL_HONOR_NUMA_FAULT = 1 << 12,
1498  
1499  	/* See also internal only FOLL flags in mm/internal.h */
1500  };
1501  
1502  #endif /* _LINUX_MM_TYPES_H */
1503