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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _LINUX_MM_TYPES_H3#define _LINUX_MM_TYPES_H4 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_ARCH26#define AT_VECTOR_SIZE_ARCH 027#endif28#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))29 30#define INIT_PASID 031 32struct address_space;33struct mem_cgroup;34 35/*36 * Each physical page in the system has a struct page associated with37 * it to keep track of whatever it is we are using the page for at the38 * moment. Note that we have no way to track which tasks are using39 * a page, though if it is a pagecache page, rmap structures can tell us40 * who is mapping it.41 *42 * If you allocate the page using alloc_pages(), you can use some of the43 * space in struct page for your own purposes. The five words in the main44 * union are available, except for bit 0 of the first word which must be45 * kept clear. Many users use this word to store a pointer to an object46 * which is guaranteed to be aligned. If you use the same storage as47 * 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 way52 * that other CPUs temporarily incrementing and then decrementing the53 * refcount does not cause problems. On receiving the page from54 * alloc_pages(), the refcount will be positive.55 *56 * If you allocate pages of order > 0, you can use some of the fields57 * in each subpage, but you may need to restore some of their values58 * 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 and62 * double-word aligned. Because struct slab currently just reinterprets the63 * 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_PAGE67#define _struct_page_alignment __aligned(2 * sizeof(unsigned long))68#else69#define _struct_page_alignment __aligned(sizeof(unsigned long))70#endif71 72struct page {73 unsigned long flags; /* Atomic flags, some possibly74 * 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(). That78 * means the other users of this union MUST NOT use the bit to79 * 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 by85 * lruvec->lru_lock. Sometimes used as a generic list86 * 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 non120 * 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 being137 * mapped so the next 3 words hold the mapping, index,138 * and private fields from the source anonymous or139 * page cache page while the page is migrated to device140 * private memory.141 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also142 * use the mapping, index, and private fields when143 * 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 here154 * allows for determining what this page is used for. The155 * tail pages of typed folios will not store a type156 * (page_type == _mapcount == -1).157 *158 * See page-flags.h for a list of page types which are currently159 * stored here.160 *161 * Owners of typed folios may reuse the lower 16 bit of the162 * head page page_type field after setting the page type,163 * but must reset these 16 bit to -1 before clearing the164 * page type.165 */166 unsigned int page_type;167 168 /*169 * For pages that are part of non-typed folios for which mappings170 * are tracked via the RMAP, encodes the number of times this page171 * is directly referenced by a page table.172 *173 * Note that the mapcount is always initialized to -1, so that174 * transitions both from it and to it can be tracked, using175 * 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_MEMCG184 unsigned long memcg_data;185#elif defined(CONFIG_SLAB_OBJ_EXT)186 unsigned long _unused_slab_obj_exts;187#endif188 189 /*190 * On machines where all RAM is mapped into kernel address space,191 * we can simply calculate the virtual address. On machines with192 * highmem some memory is mapped into kernel virtual memory193 * 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 define197 * WANT_PAGE_VIRTUAL in asm/page.h198 */199#if defined(WANT_PAGE_VIRTUAL)200 void *virtual; /* Kernel virtual address (NULL if201 not kmapped, ie. highmem) */202#endif /* WANT_PAGE_VIRTUAL */203 204#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS205 int _last_cpupid;206#endif207 208#ifdef CONFIG_KMSAN209 /*210 * KMSAN metadata for this page:211 * - shadow page: every bit indicates whether the corresponding212 * bit of the original page is initialized (0) or not (1);213 * - origin page: every 4 bytes contain an id of the stack trace214 * where the uninitialized value was created.215 */216 struct page *kmsan_shadow;217 struct page *kmsan_origin;218#endif219} _struct_page_alignment;220 221/*222 * struct encoded_page - a nonexistent type marking this pointer223 *224 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but225 * with the low bits of the pointer indicating extra context-dependent226 * information. Only used in mmu_gather handling, and this acts as a type227 * system check on that use.228 *229 * We only really have two guaranteed bits in general, although you could230 * 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 */235struct encoded_page;236 237#define ENCODED_PAGE_BITS 3ul238 239/* Perform rmap removal after we have flushed the TLB. */240#define ENCODED_PAGE_BIT_DELAY_RMAP 1ul241 242/*243 * The next item in an encoded_page array is the "nr_pages" argument, specifying244 * the number of consecutive pages starting from this page, that all belong to245 * the same folio. For example, "nr_pages" corresponds to the number of folio246 * references that must be dropped. If this bit is not set, "nr_pages" is247 * implicitly 1.248 */249#define ENCODED_PAGE_BIT_NR_PAGES_NEXT 2ul250 251static __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 257static inline unsigned long encoded_page_flags(struct encoded_page *page)258{259 return ENCODED_PAGE_BITS & (unsigned long)page;260}261 262static inline struct page *encoded_page_ptr(struct encoded_page *page)263{264 return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page);265}266 267static __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 273static __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 hidden280 * in the "index" field of the swapper address space.281 */282typedef 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 for292 * 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() to298 * 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 set317 * of bytes. It is a power-of-two in size, and it is aligned to that318 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is319 * in the page cache, it is at a file offset which is a multiple of that320 * power-of-two. It may be mapped into userspace at an address which is321 * at an arbitrary page offset, but its kernel virtual address is aligned322 * to its size.323 */324struct 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_MEMCG350 unsigned long memcg_data;351#elif defined(CONFIG_SLAB_OBJ_EXT)352 unsigned long _unused_slab_obj_exts;353#endif354#if defined(WANT_PAGE_VIRTUAL)355 void *virtual;356#endif357#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS358 int _last_cpupid;359#endif360 /* 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_64BIT374 unsigned int _folio_nr_pages;375#endif376 /* 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))404FOLIO_MATCH(flags, flags);405FOLIO_MATCH(lru, lru);406FOLIO_MATCH(mapping, mapping);407FOLIO_MATCH(compound_head, lru);408FOLIO_MATCH(index, index);409FOLIO_MATCH(private, private);410FOLIO_MATCH(_mapcount, _mapcount);411FOLIO_MATCH(_refcount, _refcount);412#ifdef CONFIG_MEMCG413FOLIO_MATCH(memcg_data, memcg_data);414#endif415#if defined(WANT_PAGE_VIRTUAL)416FOLIO_MATCH(virtual, virtual);417#endif418#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS419FOLIO_MATCH(_last_cpupid, _last_cpupid);420#endif421#undef FOLIO_MATCH422#define FOLIO_MATCH(pg, fl) \423 static_assert(offsetof(struct folio, fl) == \424 offsetof(struct page, pg) + sizeof(struct page))425FOLIO_MATCH(flags, _flags_1);426FOLIO_MATCH(compound_head, _head_1);427#undef FOLIO_MATCH428#define FOLIO_MATCH(pg, fl) \429 static_assert(offsetof(struct folio, fl) == \430 offsetof(struct page, pg) + 2 * sizeof(struct page))431FOLIO_MATCH(flags, _flags_2);432FOLIO_MATCH(compound_head, _head_2);433FOLIO_MATCH(flags, _flags_2a);434FOLIO_MATCH(compound_head, _head_2a);435#undef FOLIO_MATCH436 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 good455 * understanding of the issues.456 */457struct 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_PTLOCKS479 spinlock_t *ptl;480#else481 spinlock_t ptl;482#endif483 };484 unsigned int __page_type;485 atomic_t __page_refcount;486#ifdef CONFIG_MEMCG487 unsigned long pt_memcg_data;488#endif489};490 491#define TABLE_MATCH(pg, pt) \492 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))493TABLE_MATCH(flags, __page_flags);494TABLE_MATCH(compound_head, pt_list);495TABLE_MATCH(compound_head, _pt_pad_1);496TABLE_MATCH(mapping, __page_mapping);497TABLE_MATCH(index, pt_index);498TABLE_MATCH(rcu_head, pt_rcu_head);499TABLE_MATCH(page_type, __page_type);500TABLE_MATCH(_refcount, __page_refcount);501#ifdef CONFIG_MEMCG502TABLE_MATCH(memcg_data, pt_memcg_data);503#endif504#undef TABLE_MATCH505static_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 architectures521 */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 only529 * checked by the VM on the head page. So page_private on the tail pages530 * should be used for data that's ancillary to the head page (eg attaching531 * buffer heads to tail pages after attaching buffer heads to the head page)532 */533#define page_private(page) ((page)->private)534 535static inline void set_page_private(struct page *page, unsigned long private)536{537 page->private = private;538}539 540static inline void *folio_get_private(struct folio *folio)541{542 return folio->private;543}544 545struct page_frag_cache {546 void * va;547#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)548 __u16 offset;549 __u16 size;550#else551 __u32 offset;552#endif553 /* we maintain a pagecount bias, so that we dont dirty cache line554 * containing page->_refcount every time we allocate a fragment.555 */556 unsigned int pagecnt_bias;557 bool pfmemalloc;558};559 560typedef unsigned long vm_flags_t;561 562/*563 * A region containing a mapping of a non-memory backed file under NOMMU564 * conditions. These are held in a global tree and are pinned by the VMAs that565 * map parts of them.566 */567struct 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 for578 * this region */579};580 581#ifdef CONFIG_USERFAULTFD582#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })583struct vm_userfaultfd_ctx {584 struct userfaultfd_ctx *ctx;585};586#else /* CONFIG_USERFAULTFD */587#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})588struct vm_userfaultfd_ctx {};589#endif /* CONFIG_USERFAULTFD */590 591struct 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_NAME598/*599 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should600 * either keep holding the lock while using the returned pointer or it should601 * raise anon_vma_name refcount before releasing the lock.602 */603struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);604struct anon_vma_name *anon_vma_name_alloc(const char *name);605void anon_vma_name_free(struct kref *kref);606#else /* CONFIG_ANON_VMA_NAME */607static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)608{609 return NULL;610}611 612static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)613{614 return NULL;615}616#endif617 618struct vma_lock {619 struct rw_semaphore lock;620};621 622struct vma_numab_state {623 /*624 * Initialised as time in 'jiffies' after which VMA625 * should be scanned. Delays first scan of new VMA by at626 * least sysctl_numa_balancing_scan_delay:627 */628 unsigned long next_scan;629 630 /*631 * Time in jiffies when pids_active[] is reset to632 * detect phase change behaviour:633 */634 unsigned long pids_active_reset;635 636 /*637 * Approximate tracking of PIDs that trapped a NUMA hinting638 * fault. May produce false positives due to hash collisions.639 *640 * [0] Previous PID tracking641 * [1] Current PID tracking642 *643 * Window moves after next_pid_reset has expired approximately644 * 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_seq654 */655 int prev_scan_seq;656};657 658/*659 * This struct describes a virtual memory area. There is one of these660 * per VM-area/task. A VM area is any part of the process virtual memory661 * space that has a special rule for the page-fault handlers (ie a shared662 * library, the executable area etc).663 *664 * Only explicitly marked struct members may be accessed by RCU readers before665 * getting a stable reference.666 */667struct 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_LOCK677 struct rcu_head vm_rcu; /* Used for deferred freeing. */678#endif679 };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_LOCK698 /*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 bailout712 * while holding nothing (except RCU to keep the VMA struct allocated).713 *714 * This sequence counter is explicitly allowed to overflow; sequence715 * counter reuse can only lead to occasional unnecessary use of the716 * slowpath.717 */718 int vm_lock_seq;719 /* Unstable RCU readers are allowed to read this. */720 struct vma_lock *vm_lock;721#endif722 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_vma735 * list, after a COW of one of the file pages. A MAP_SHARED vma736 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack737 * 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_SIZE748 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_NAME753 /*754 * For private and shared anonymous mappings, a pointer to a null755 * terminated string containing the name given to the vma, or NULL if756 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.757 */758 struct anon_vma_name *anon_name;759#endif760#ifdef CONFIG_SWAP761 atomic_long_t swap_readahead_info;762#endif763#ifndef CONFIG_MMU764 struct vm_region *vm_region; /* NOMMU mapping region */765#endif766#ifdef CONFIG_NUMA767 struct mempolicy *vm_policy; /* NUMA policy for the VMA */768#endif769#ifdef CONFIG_NUMA_BALANCING770 struct vma_numab_state *numab_state; /* NUMA Balancing state */771#endif772 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;773} __randomize_layout;774 775#ifdef CONFIG_NUMA776#define vma_policy(vma) ((vma)->vm_policy)777#else778#define vma_policy(vma) NULL779#endif780 781#ifdef CONFIG_SCHED_MM_CID782struct mm_cid {783 u64 time;784 int cid;785};786#endif787 788struct kioctx_table;789struct iommu_mm_data;790struct mm_struct {791 struct {792 /*793 * Fields which are often written to are placed in a separate794 * cache line.795 */796 struct {797 /**798 * @mm_count: The number of references to &struct799 * mm_struct (@mm_users count as 1).800 *801 * Use mmgrab()/mmdrop() to modify. When this drops to802 * 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_BASES812 /* Base addresses for compatible mmap() */813 unsigned long mmap_compat_base;814 unsigned long mmap_compat_legacy_base;815#endif816 unsigned long task_size; /* size of task vm space */817 pgd_t * pgd;818 819#ifdef CONFIG_MEMBARRIER820 /**821 * @membarrier_state: Flags controlling membarrier behavior.822 *823 * This field is close to @pgd to hopefully fit in the same824 * cache-line, which needs to be touched by switch_mm().825 */826 atomic_t membarrier_state;827#endif828 829 /**830 * @mm_users: The number of users including userspace.831 *832 * Use mmget()/mmget_not_zero()/mmput() to modify. When this833 * drops to 0 (i.e. when the task exits and there are no other834 * temporary reference holders), we also release a reference on835 * @mm_count (which may then free the &struct mm_struct if836 * @mm_count also drops to 0).837 */838 atomic_t mm_users;839 840#ifdef CONFIG_SCHED_MM_CID841 /**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 respective846 * 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#endif856#ifdef CONFIG_MMU857 atomic_long_t pgtables_bytes; /* size of all page tables */858#endif859 int map_count; /* number of VMAs */860 861 spinlock_t page_table_lock; /* Protects page tables and some862 * counters863 */864 /*865 * With some kernel config, the current mmap_lock's offset866 * inside 'mm_struct' is at 0x120, which is very optimal, as867 * its two hot fields 'count' and 'owner' sit in 2 different868 * cachelines, and when mmap_lock is highly contended, both869 * of the 2 fields will be accessed frequently, current layout870 * will help to reduce cache bouncing.871 *872 * So please be careful with adding new fields before873 * mmap_lock, which can easily push the 2 fields into one874 * cacheline.875 */876 struct rw_semaphore mmap_lock;877 878 struct list_head mmlist; /* List of maybe swapped mm's. These879 * are globally strung together off880 * init_mm.mmlist, and are protected881 * by mmlist_lock882 */883#ifdef CONFIG_PER_VMA_LOCK884 /*885 * This field has lock-like semantics, meaning it is sometimes886 * accessed with ACQUIRE/RELEASE semantics.887 * Roughly speaking, incrementing the sequence number is888 * equivalent to releasing locks on VMAs; reading the sequence889 * number can be part of taking a read lock on a VMA.890 *891 * Can be modified under write mmap_lock using RELEASE892 * semantics.893 * Can be read with no other protection when holding write894 * mmap_lock.895 * Can be read with ACQUIRE semantics if not holding write896 * mmap_lock.897 */898 int mm_lock_seq;899#endif900 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 write915 * 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_AIO938 spinlock_t ioctx_lock;939 struct kioctx_table __rcu *ioctx_table;940#endif941#ifdef CONFIG_MEMCG942 /*943 * "owner" points to a task that is regarded as the canonical944 * user/owner of this mm. All of the following must be true in945 * order for it to be changed:946 *947 * current == mm->owner948 * current->mm != mm949 * new_owner->mm == mm950 * new_owner->alloc_lock is held951 */952 struct task_struct __rcu *owner;953#endif954 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_NOTIFIER959 struct mmu_notifier_subscriptions *notifier_subscriptions;960#endif961#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS)962 pgtable_t pmd_huge_pte; /* protected by page_table_lock */963#endif964#ifdef CONFIG_NUMA_BALANCING965 /*966 * numa_next_scan is the next time that PTEs will be remapped967 * PROT_NONE to trigger NUMA hinting faults; such faults gather968 * 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#endif978 /*979 * An operation with batched TLB flushing is going on. Anything980 * that can move process memory needs to flush the TLB when981 * moving a PROT_NONE mapped page.982 */983 atomic_t tlb_flush_pending;984#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH985 /* See flush_tlb_batched_pending() */986 atomic_t tlb_flush_batched;987#endif988 struct uprobes_state uprobes_state;989#ifdef CONFIG_PREEMPT_RT990 struct rcu_head delayed_drop;991#endif992#ifdef CONFIG_HUGETLB_PAGE993 atomic_long_t hugetlb_usage;994#endif995 struct work_struct async_put_work;996 997#ifdef CONFIG_IOMMU_MM_DATA998 struct iommu_mm_data *iommu_mm;999#endif1000#ifdef CONFIG_KSM1001 /*1002 * Represent how many pages of this process are involved in KSM1003 * merging (not including ksm_zero_pages).1004 */1005 unsigned long ksm_merging_pages;1006 /*1007 * Represent how many pages are checked for ksm merging1008 * including merged and not merged.1009 */1010 unsigned long ksm_rmap_items;1011 /*1012 * Represent how many empty pages are merged with kernel zero1013 * 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_MMU1018 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 of1023 * whether it has been used since the last time per-node1024 * page table walkers cleared the corresponding bits.1025 */1026 unsigned long bitmap;1027#ifdef CONFIG_MEMCG1028 /* points to the memcg of "owner" above */1029 struct mem_cgroup *memcg;1030#endif1031 } 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 it1037 * 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)1044extern struct mm_struct init_mm;1045 1046/* Pointer magic because the dynamic array size confuses some compilers. */1047static 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. */1056static inline cpumask_t *mm_cpumask(struct mm_struct *mm)1057{1058 return (struct cpumask *)&mm->cpu_bitmap;1059}1060 1061#ifdef CONFIG_LRU_GEN1062 1063struct 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_MMU1073 1074void lru_gen_add_mm(struct mm_struct *mm);1075void lru_gen_del_mm(struct mm_struct *mm);1076void lru_gen_migrate_mm(struct mm_struct *mm);1077 1078static 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_MEMCG1083 mm->lru_gen.memcg = NULL;1084#endif1085}1086 1087static 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 been1091 * used since the last time it cleared the bitmap. So it might be worth1092 * 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 1099static inline void lru_gen_add_mm(struct mm_struct *mm)1100{1101}1102 1103static inline void lru_gen_del_mm(struct mm_struct *mm)1104{1105}1106 1107static inline void lru_gen_migrate_mm(struct mm_struct *mm)1108{1109}1110 1111static inline void lru_gen_init_mm(struct mm_struct *mm)1112{1113}1114 1115static inline void lru_gen_use_mm(struct mm_struct *mm)1116{1117}1118 1119#endif /* CONFIG_LRU_GEN_WALKS_MMU */1120 1121struct 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 1135static 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_CID1142 1143enum mm_cid_state {1144 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */1145 MM_CID_LAZY_PUT = (1U << 31),1146};1147 1148static inline bool mm_cid_is_unset(int cid)1149{1150 return cid == MM_CID_UNSET;1151}1152 1153static inline bool mm_cid_is_lazy_put(int cid)1154{1155 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT);1156}1157 1158static inline bool mm_cid_is_valid(int cid)1159{1160 return !(cid & MM_CID_LAZY_PUT);1161}1162 1163static inline int mm_cid_set_lazy_put(int cid)1164{1165 return cid | MM_CID_LAZY_PUT;1166}1167 1168static 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. */1174static 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 1184static 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 1197static 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 1207static inline void mm_destroy_cid(struct mm_struct *mm)1208{1209 free_percpu(mm->pcpu_cid);1210 mm->pcpu_cid = NULL;1211}1212 1213static inline unsigned int mm_cid_size(void)1214{1215 return cpumask_size();1216}1217#else /* CONFIG_SCHED_MM_CID */1218static inline void mm_init_cid(struct mm_struct *mm) { }1219static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; }1220static inline void mm_destroy_cid(struct mm_struct *mm) { }1221static inline unsigned int mm_cid_size(void)1222{1223 return 0;1224}1225#endif /* CONFIG_SCHED_MM_CID */1226 1227struct mmu_gather;1228extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm);1229extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm);1230extern void tlb_finish_mmu(struct mmu_gather *tlb) HWJS_SUSPENDS;1231 1232struct 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 */1239typedef __bitwise unsigned int vm_fault_t;1240 1241/**1242 * enum vm_fault_reason - Page fault handlers return a bitmask of1243 * these values to tell the core VM what happened when handling the1244 * fault. Used to decide whether a process gets delivered SIGBUS or1245 * just gets major/minor fault counters bumped up.1246 *1247 * @VM_FAULT_OOM: Out Of Memory1248 * @VM_FAULT_SIGBUS: Bad access1249 * @VM_FAULT_MAJOR: Page read from storage1250 * @VM_FAULT_HWPOISON: Hit poisoned small page1251 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded1252 * in upper bits1253 * @VM_FAULT_SIGSEGV: segmentation fault1254 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page1255 * @VM_FAULT_LOCKED: ->fault locked the returned page1256 * @VM_FAULT_RETRY: ->fault blocked, must retry1257 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small1258 * @VM_FAULT_DONE_COW: ->fault has fully handled COW1259 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs1260 * fsync() to complete (for synchronous page faults1261 * in DAX)1262 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released1263 * @VM_FAULT_HINDEX_MASK: mask HINDEX value1264 *1265 */1266enum 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 1306struct vm_special_mapping {1307 const char *name; /* The name, e.g. "[vdso]". */1308 1309 /*1310 * If .fault is not provided, this points to a1311 * 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 faults1319 * 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 1332enum 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 a1354 * COW mapping, making sure that an exclusive anon page is1355 * 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 specify1361 * whether we would allow page faults to retry by specifying these two1362 * fault flags correctly. Currently there can be three legal combinations:1363 *1364 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and1365 * this is the first try1366 *1367 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and1368 * we've already tried at least once1369 *1370 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry1371 *1372 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never1373 * 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 on1375 * continuous faults with flags (b). We should always try to detect pending1376 * signals before a retry to make sure the continuous page faults can still be1377 * 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 when1381 * applied to mappings that are not COW mappings.1382 */1383enum 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 1399typedef unsigned int __bitwise zap_flags_t;1400 1401/* Flags for clear_young_dirty_ptes(). */1402typedef 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 each1412 * 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 the1416 * lifetime enforced by the filesystem and we need guarantees that longterm1417 * users like RDMA and V4L2 only establish mappings which coordinate usage with1418 * the filesystem. Ideas for this coordination include revoking the longterm1419 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was1420 * added after the problem with filesystems was found FS DAX VMAs are1421 * specifically failed. Filesystem pages are still subject to bugs and use of1422 * FOLL_LONGTERM should be avoided on those pages.1423 *1424 * In the CMA case: long term pins in a CMA region would unnecessarily fragment1425 * that region. And so, CMA attempts to migrate the page before pinning, when1426 * 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 for1430 * 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 is1432 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages1433 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by1434 * a call to unpin_user_page().1435 *1436 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different1437 * and separate refcounting mechanisms, however, and that means that each has1438 * 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-based1446 * calls applied to them, and that's perfectly OK. This is a constraint on the1447 * callers, not on the pages.)1448 *1449 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never1450 * directly by the caller. That's in order to help avoid mismatches when1451 * 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 1457enum {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 waiting1468 * upon it1469 */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 indefinite1479 * time period _often_ under userspace control. This is in contrast to1480 * 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 a1493 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE1494 * apply). get_user_pages_fast_only() always implicitly honors NUMA1495 * 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