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 * If your page will not be mapped to userspace, you can also use the four 50 * bytes in the mapcount union, but you must call page_mapcount_reset() 51 * before freeing it. 52 * 53 * If you want to use the refcount field, it must be used in such a way 54 * that other CPUs temporarily incrementing and then decrementing the 55 * refcount does not cause problems. On receiving the page from 56 * alloc_pages(), the refcount will be positive. 57 * 58 * If you allocate pages of order > 0, you can use some of the fields 59 * in each subpage, but you may need to restore some of their values 60 * afterwards. 61 * 62 * SLUB uses cmpxchg_double() to atomically update its freelist and counters. 63 * That requires that freelist & counters in struct slab be adjacent and 64 * double-word aligned. Because struct slab currently just reinterprets the 65 * bits of struct page, we align all struct pages to double-word boundaries, 66 * and ensure that 'freelist' is aligned within struct slab. 67 */ 68 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 69 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) 70 #else 71 #define _struct_page_alignment __aligned(sizeof(unsigned long)) 72 #endif 73 74 struct page { 75 unsigned long flags; /* Atomic flags, some possibly 76 * updated asynchronously */ 77 /* 78 * Five words (20/40 bytes) are available in this union. 79 * WARNING: bit 0 of the first word is used for PageTail(). That 80 * means the other users of this union MUST NOT use the bit to 81 * avoid collision and false-positive PageTail(). 82 */ 83 union { 84 struct { /* Page cache and anonymous pages */ 85 /** 86 * @lru: Pageout list, eg. active_list protected by 87 * lruvec->lru_lock. Sometimes used as a generic list 88 * by the page owner. 89 */ 90 union { 91 struct list_head lru; 92 93 /* Or, for the Unevictable "LRU list" slot */ 94 struct { 95 /* Always even, to negate PageTail */ 96 void *__filler; 97 /* Count page's or folio's mlocks */ 98 unsigned int mlock_count; 99 }; 100 101 /* Or, free page */ 102 struct list_head buddy_list; 103 struct list_head pcp_list; 104 }; 105 /* See page-flags.h for PAGE_MAPPING_FLAGS */ 106 struct address_space *mapping; 107 union { 108 pgoff_t index; /* Our offset within mapping. */ 109 unsigned long share; /* share count for fsdax */ 110 }; 111 /** 112 * @private: Mapping-private opaque data. 113 * Usually used for buffer_heads if PagePrivate. 114 * Used for swp_entry_t if PageSwapCache. 115 * Indicates order in the buddy system if PageBuddy. 116 */ 117 unsigned long private; 118 }; 119 struct { /* page_pool used by netstack */ 120 /** 121 * @pp_magic: magic value to avoid recycling non 122 * page_pool allocated pages. 123 */ 124 unsigned long pp_magic; 125 struct page_pool *pp; 126 unsigned long _pp_mapping_pad; 127 unsigned long dma_addr; 128 atomic_long_t pp_frag_count; 129 }; 130 struct { /* Tail pages of compound page */ 131 unsigned long compound_head; /* Bit zero is set */ 132 }; 133 struct { /* ZONE_DEVICE pages */ 134 /** @pgmap: Points to the hosting device page map. */ 135 struct dev_pagemap *pgmap; 136 void *zone_device_data; 137 /* 138 * ZONE_DEVICE private pages are counted as being 139 * mapped so the next 3 words hold the mapping, index, 140 * and private fields from the source anonymous or 141 * page cache page while the page is migrated to device 142 * private memory. 143 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also 144 * use the mapping, index, and private fields when 145 * pmem backed DAX files are mapped. 146 */ 147 }; 148 149 /** @rcu_head: You can use this to free a page by RCU. */ 150 struct rcu_head rcu_head; 151 }; 152 153 union { /* This union is 4 bytes in size. */ 154 /* 155 * If the page can be mapped to userspace, encodes the number 156 * of times this page is referenced by a page table. 157 */ 158 atomic_t _mapcount; 159 160 /* 161 * If the page is neither PageSlab nor mappable to userspace, 162 * the value stored here may help determine what this page 163 * is used for. See page-flags.h for a list of page types 164 * which are currently stored here. 165 */ 166 unsigned int page_type; 167 }; 168 169 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */ 170 atomic_t _refcount; 171 172 #ifdef CONFIG_MEMCG 173 unsigned long memcg_data; 174 #endif 175 176 /* 177 * On machines where all RAM is mapped into kernel address space, 178 * we can simply calculate the virtual address. On machines with 179 * highmem some memory is mapped into kernel virtual memory 180 * dynamically, so we need a place to store that address. 181 * Note that this field could be 16 bits on x86 ... ;) 182 * 183 * Architectures with slow multiplication can define 184 * WANT_PAGE_VIRTUAL in asm/page.h 185 */ 186 #if defined(WANT_PAGE_VIRTUAL) 187 void *virtual; /* Kernel virtual address (NULL if 188 not kmapped, ie. highmem) */ 189 #endif /* WANT_PAGE_VIRTUAL */ 190 191 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 192 int _last_cpupid; 193 #endif 194 195 #ifdef CONFIG_KMSAN 196 /* 197 * KMSAN metadata for this page: 198 * - shadow page: every bit indicates whether the corresponding 199 * bit of the original page is initialized (0) or not (1); 200 * - origin page: every 4 bytes contain an id of the stack trace 201 * where the uninitialized value was created. 202 */ 203 struct page *kmsan_shadow; 204 struct page *kmsan_origin; 205 #endif 206 } _struct_page_alignment; 207 208 /* 209 * struct encoded_page - a nonexistent type marking this pointer 210 * 211 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but 212 * with the low bits of the pointer indicating extra context-dependent 213 * information. Not super-common, but happens in mmu_gather and mlock 214 * handling, and this acts as a type system check on that use. 215 * 216 * We only really have two guaranteed bits in general, although you could 217 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 218 * for more. 219 * 220 * Use the supplied helper functions to endcode/decode the pointer and bits. 221 */ 222 struct encoded_page; 223 #define ENCODE_PAGE_BITS 3ul 224 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags) 225 { 226 BUILD_BUG_ON(flags > ENCODE_PAGE_BITS); 227 return (struct encoded_page *)(flags | (unsigned long)page); 228 } 229 230 static inline unsigned long encoded_page_flags(struct encoded_page *page) 231 { 232 return ENCODE_PAGE_BITS & (unsigned long)page; 233 } 234 235 static inline struct page *encoded_page_ptr(struct encoded_page *page) 236 { 237 return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page); 238 } 239 240 /* 241 * A swap entry has to fit into a "unsigned long", as the entry is hidden 242 * in the "index" field of the swapper address space. 243 */ 244 typedef struct { 245 unsigned long val; 246 } swp_entry_t; 247 248 /** 249 * struct folio - Represents a contiguous set of bytes. 250 * @flags: Identical to the page flags. 251 * @lru: Least Recently Used list; tracks how recently this folio was used. 252 * @mlock_count: Number of times this folio has been pinned by mlock(). 253 * @mapping: The file this page belongs to, or refers to the anon_vma for 254 * anonymous memory. 255 * @index: Offset within the file, in units of pages. For anonymous memory, 256 * this is the index from the beginning of the mmap. 257 * @private: Filesystem per-folio data (see folio_attach_private()). 258 * @swap: Used for swp_entry_t if folio_test_swapcache(). 259 * @_mapcount: Do not access this member directly. Use folio_mapcount() to 260 * find out how many times this folio is mapped by userspace. 261 * @_refcount: Do not access this member directly. Use folio_ref_count() 262 * to find how many references there are to this folio. 263 * @memcg_data: Memory Control Group data. 264 * @virtual: Virtual address in the kernel direct map. 265 * @_last_cpupid: IDs of last CPU and last process that accessed the folio. 266 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount(). 267 * @_nr_pages_mapped: Do not use directly, call folio_mapcount(). 268 * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). 269 * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). 270 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h. 271 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h. 272 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h. 273 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head(). 274 * @_deferred_list: Folios to be split under memory pressure. 275 * 276 * A folio is a physically, virtually and logically contiguous set 277 * of bytes. It is a power-of-two in size, and it is aligned to that 278 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is 279 * in the page cache, it is at a file offset which is a multiple of that 280 * power-of-two. It may be mapped into userspace at an address which is 281 * at an arbitrary page offset, but its kernel virtual address is aligned 282 * to its size. 283 */ 284 struct folio { 285 /* private: don't document the anon union */ 286 union { 287 struct { 288 /* public: */ 289 unsigned long flags; 290 union { 291 struct list_head lru; 292 /* private: avoid cluttering the output */ 293 struct { 294 void *__filler; 295 /* public: */ 296 unsigned int mlock_count; 297 /* private: */ 298 }; 299 /* public: */ 300 }; 301 struct address_space *mapping; 302 pgoff_t index; 303 union { 304 void *private; 305 swp_entry_t swap; 306 }; 307 atomic_t _mapcount; 308 atomic_t _refcount; 309 #ifdef CONFIG_MEMCG 310 unsigned long memcg_data; 311 #endif 312 #if defined(WANT_PAGE_VIRTUAL) 313 void *virtual; 314 #endif 315 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 316 int _last_cpupid; 317 #endif 318 /* private: the union with struct page is transitional */ 319 }; 320 struct page page; 321 }; 322 union { 323 struct { 324 unsigned long _flags_1; 325 unsigned long _head_1; 326 unsigned long _folio_avail; 327 /* public: */ 328 atomic_t _entire_mapcount; 329 atomic_t _nr_pages_mapped; 330 atomic_t _pincount; 331 #ifdef CONFIG_64BIT 332 unsigned int _folio_nr_pages; 333 #endif 334 /* private: the union with struct page is transitional */ 335 }; 336 struct page __page_1; 337 }; 338 union { 339 struct { 340 unsigned long _flags_2; 341 unsigned long _head_2; 342 /* public: */ 343 void *_hugetlb_subpool; 344 void *_hugetlb_cgroup; 345 void *_hugetlb_cgroup_rsvd; 346 void *_hugetlb_hwpoison; 347 /* private: the union with struct page is transitional */ 348 }; 349 struct { 350 unsigned long _flags_2a; 351 unsigned long _head_2a; 352 /* public: */ 353 struct list_head _deferred_list; 354 /* private: the union with struct page is transitional */ 355 }; 356 struct page __page_2; 357 }; 358 }; 359 360 #define FOLIO_MATCH(pg, fl) \ 361 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl)) 362 FOLIO_MATCH(flags, flags); 363 FOLIO_MATCH(lru, lru); 364 FOLIO_MATCH(mapping, mapping); 365 FOLIO_MATCH(compound_head, lru); 366 FOLIO_MATCH(index, index); 367 FOLIO_MATCH(private, private); 368 FOLIO_MATCH(_mapcount, _mapcount); 369 FOLIO_MATCH(_refcount, _refcount); 370 #ifdef CONFIG_MEMCG 371 FOLIO_MATCH(memcg_data, memcg_data); 372 #endif 373 #if defined(WANT_PAGE_VIRTUAL) 374 FOLIO_MATCH(virtual, virtual); 375 #endif 376 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 377 FOLIO_MATCH(_last_cpupid, _last_cpupid); 378 #endif 379 #undef FOLIO_MATCH 380 #define FOLIO_MATCH(pg, fl) \ 381 static_assert(offsetof(struct folio, fl) == \ 382 offsetof(struct page, pg) + sizeof(struct page)) 383 FOLIO_MATCH(flags, _flags_1); 384 FOLIO_MATCH(compound_head, _head_1); 385 #undef FOLIO_MATCH 386 #define FOLIO_MATCH(pg, fl) \ 387 static_assert(offsetof(struct folio, fl) == \ 388 offsetof(struct page, pg) + 2 * sizeof(struct page)) 389 FOLIO_MATCH(flags, _flags_2); 390 FOLIO_MATCH(compound_head, _head_2); 391 FOLIO_MATCH(flags, _flags_2a); 392 FOLIO_MATCH(compound_head, _head_2a); 393 #undef FOLIO_MATCH 394 395 /** 396 * struct ptdesc - Memory descriptor for page tables. 397 * @__page_flags: Same as page flags. Unused for page tables. 398 * @pt_rcu_head: For freeing page table pages. 399 * @pt_list: List of used page tables. Used for s390 and x86. 400 * @_pt_pad_1: Padding that aliases with page's compound head. 401 * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs. 402 * @__page_mapping: Aliases with page->mapping. Unused for page tables. 403 * @pt_mm: Used for x86 pgds. 404 * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only. 405 * @_pt_pad_2: Padding to ensure proper alignment. 406 * @ptl: Lock for the page table. 407 * @__page_type: Same as page->page_type. Unused for page tables. 408 * @_refcount: Same as page refcount. Used for s390 page tables. 409 * @pt_memcg_data: Memcg data. Tracked for page tables here. 410 * 411 * This struct overlays struct page for now. Do not modify without a good 412 * understanding of the issues. 413 */ 414 struct ptdesc { 415 unsigned long __page_flags; 416 417 union { 418 struct rcu_head pt_rcu_head; 419 struct list_head pt_list; 420 struct { 421 unsigned long _pt_pad_1; 422 pgtable_t pmd_huge_pte; 423 }; 424 }; 425 unsigned long __page_mapping; 426 427 union { 428 struct mm_struct *pt_mm; 429 atomic_t pt_frag_refcount; 430 }; 431 432 union { 433 unsigned long _pt_pad_2; 434 #if ALLOC_SPLIT_PTLOCKS 435 spinlock_t *ptl; 436 #else 437 spinlock_t ptl; 438 #endif 439 }; 440 unsigned int __page_type; 441 atomic_t _refcount; 442 #ifdef CONFIG_MEMCG 443 unsigned long pt_memcg_data; 444 #endif 445 }; 446 447 #define TABLE_MATCH(pg, pt) \ 448 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt)) 449 TABLE_MATCH(flags, __page_flags); 450 TABLE_MATCH(compound_head, pt_list); 451 TABLE_MATCH(compound_head, _pt_pad_1); 452 TABLE_MATCH(mapping, __page_mapping); 453 TABLE_MATCH(rcu_head, pt_rcu_head); 454 TABLE_MATCH(page_type, __page_type); 455 TABLE_MATCH(_refcount, _refcount); 456 #ifdef CONFIG_MEMCG 457 TABLE_MATCH(memcg_data, pt_memcg_data); 458 #endif 459 #undef TABLE_MATCH 460 static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); 461 462 #define ptdesc_page(pt) (_Generic((pt), \ 463 const struct ptdesc *: (const struct page *)(pt), \ 464 struct ptdesc *: (struct page *)(pt))) 465 466 #define ptdesc_folio(pt) (_Generic((pt), \ 467 const struct ptdesc *: (const struct folio *)(pt), \ 468 struct ptdesc *: (struct folio *)(pt))) 469 470 #define page_ptdesc(p) (_Generic((p), \ 471 const struct page *: (const struct ptdesc *)(p), \ 472 struct page *: (struct ptdesc *)(p))) 473 474 /* 475 * Used for sizing the vmemmap region on some architectures 476 */ 477 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) 478 479 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) 480 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) 481 482 /* 483 * page_private can be used on tail pages. However, PagePrivate is only 484 * checked by the VM on the head page. So page_private on the tail pages 485 * should be used for data that's ancillary to the head page (eg attaching 486 * buffer heads to tail pages after attaching buffer heads to the head page) 487 */ 488 #define page_private(page) ((page)->private) 489 490 static inline void set_page_private(struct page *page, unsigned long private) 491 { 492 page->private = private; 493 } 494 495 static inline void *folio_get_private(struct folio *folio) 496 { 497 return folio->private; 498 } 499 500 struct page_frag_cache { 501 void * va; 502 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) 503 __u16 offset; 504 __u16 size; 505 #else 506 __u32 offset; 507 #endif 508 /* we maintain a pagecount bias, so that we dont dirty cache line 509 * containing page->_refcount every time we allocate a fragment. 510 */ 511 unsigned int pagecnt_bias; 512 bool pfmemalloc; 513 }; 514 515 typedef unsigned long vm_flags_t; 516 517 /* 518 * A region containing a mapping of a non-memory backed file under NOMMU 519 * conditions. These are held in a global tree and are pinned by the VMAs that 520 * map parts of them. 521 */ 522 struct vm_region { 523 struct rb_node vm_rb; /* link in global region tree */ 524 vm_flags_t vm_flags; /* VMA vm_flags */ 525 unsigned long vm_start; /* start address of region */ 526 unsigned long vm_end; /* region initialised to here */ 527 unsigned long vm_top; /* region allocated to here */ 528 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 529 struct file *vm_file; /* the backing file or NULL */ 530 531 int vm_usage; /* region usage count (access under nommu_region_sem) */ 532 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 533 * this region */ 534 }; 535 536 #ifdef CONFIG_USERFAULTFD 537 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 538 struct vm_userfaultfd_ctx { 539 struct userfaultfd_ctx *ctx; 540 }; 541 #else /* CONFIG_USERFAULTFD */ 542 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 543 struct vm_userfaultfd_ctx {}; 544 #endif /* CONFIG_USERFAULTFD */ 545 546 struct anon_vma_name { 547 struct kref kref; 548 /* The name needs to be at the end because it is dynamically sized. */ 549 char name[]; 550 }; 551 552 #ifdef CONFIG_ANON_VMA_NAME 553 /* 554 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should 555 * either keep holding the lock while using the returned pointer or it should 556 * raise anon_vma_name refcount before releasing the lock. 557 */ 558 struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); 559 struct anon_vma_name *anon_vma_name_alloc(const char *name); 560 void anon_vma_name_free(struct kref *kref); 561 #else /* CONFIG_ANON_VMA_NAME */ 562 static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) 563 { 564 return NULL; 565 } 566 567 static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) 568 { 569 return NULL; 570 } 571 #endif 572 573 struct vma_lock { 574 struct rw_semaphore lock; 575 }; 576 577 struct vma_numab_state { 578 /* 579 * Initialised as time in 'jiffies' after which VMA 580 * should be scanned. Delays first scan of new VMA by at 581 * least sysctl_numa_balancing_scan_delay: 582 */ 583 unsigned long next_scan; 584 585 /* 586 * Time in jiffies when pids_active[] is reset to 587 * detect phase change behaviour: 588 */ 589 unsigned long pids_active_reset; 590 591 /* 592 * Approximate tracking of PIDs that trapped a NUMA hinting 593 * fault. May produce false positives due to hash collisions. 594 * 595 * [0] Previous PID tracking 596 * [1] Current PID tracking 597 * 598 * Window moves after next_pid_reset has expired approximately 599 * every VMA_PID_RESET_PERIOD jiffies: 600 */ 601 unsigned long pids_active[2]; 602 603 /* 604 * MM scan sequence ID when the VMA was last completely scanned. 605 * A VMA is not eligible for scanning if prev_scan_seq == numa_scan_seq 606 */ 607 int prev_scan_seq; 608 }; 609 610 /* 611 * This struct describes a virtual memory area. There is one of these 612 * per VM-area/task. A VM area is any part of the process virtual memory 613 * space that has a special rule for the page-fault handlers (ie a shared 614 * library, the executable area etc). 615 */ 616 struct vm_area_struct { 617 /* The first cache line has the info for VMA tree walking. */ 618 619 union { 620 struct { 621 /* VMA covers [vm_start; vm_end) addresses within mm */ 622 unsigned long vm_start; 623 unsigned long vm_end; 624 }; 625 #ifdef CONFIG_PER_VMA_LOCK 626 struct rcu_head vm_rcu; /* Used for deferred freeing. */ 627 #endif 628 }; 629 630 struct mm_struct *vm_mm; /* The address space we belong to. */ 631 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 632 633 /* 634 * Flags, see mm.h. 635 * To modify use vm_flags_{init|reset|set|clear|mod} functions. 636 */ 637 union { 638 const vm_flags_t vm_flags; 639 vm_flags_t __private __vm_flags; 640 }; 641 642 #ifdef CONFIG_PER_VMA_LOCK 643 /* 644 * Can only be written (using WRITE_ONCE()) while holding both: 645 * - mmap_lock (in write mode) 646 * - vm_lock->lock (in write mode) 647 * Can be read reliably while holding one of: 648 * - mmap_lock (in read or write mode) 649 * - vm_lock->lock (in read or write mode) 650 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout 651 * while holding nothing (except RCU to keep the VMA struct allocated). 652 * 653 * This sequence counter is explicitly allowed to overflow; sequence 654 * counter reuse can only lead to occasional unnecessary use of the 655 * slowpath. 656 */ 657 int vm_lock_seq; 658 struct vma_lock *vm_lock; 659 660 /* Flag to indicate areas detached from the mm->mm_mt tree */ 661 bool detached; 662 #endif 663 664 /* 665 * For areas with an address space and backing store, 666 * linkage into the address_space->i_mmap interval tree. 667 * 668 */ 669 struct { 670 struct rb_node rb; 671 unsigned long rb_subtree_last; 672 } shared; 673 674 /* 675 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 676 * list, after a COW of one of the file pages. A MAP_SHARED vma 677 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 678 * or brk vma (with NULL file) can only be in an anon_vma list. 679 */ 680 struct list_head anon_vma_chain; /* Serialized by mmap_lock & 681 * page_table_lock */ 682 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 683 684 /* Function pointers to deal with this struct. */ 685 const struct vm_operations_struct *vm_ops; 686 687 /* Information about our backing store: */ 688 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 689 units */ 690 struct file * vm_file; /* File we map to (can be NULL). */ 691 void * vm_private_data; /* was vm_pte (shared mem) */ 692 693 #ifdef CONFIG_ANON_VMA_NAME 694 /* 695 * For private and shared anonymous mappings, a pointer to a null 696 * terminated string containing the name given to the vma, or NULL if 697 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access. 698 */ 699 struct anon_vma_name *anon_name; 700 #endif 701 #ifdef CONFIG_SWAP 702 atomic_long_t swap_readahead_info; 703 #endif 704 #ifndef CONFIG_MMU 705 struct vm_region *vm_region; /* NOMMU mapping region */ 706 #endif 707 #ifdef CONFIG_NUMA 708 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 709 #endif 710 #ifdef CONFIG_NUMA_BALANCING 711 struct vma_numab_state *numab_state; /* NUMA Balancing state */ 712 #endif 713 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 714 } __randomize_layout; 715 716 #ifdef CONFIG_NUMA 717 #define vma_policy(vma) ((vma)->vm_policy) 718 #else 719 #define vma_policy(vma) NULL 720 #endif 721 722 #ifdef CONFIG_SCHED_MM_CID 723 struct mm_cid { 724 u64 time; 725 int cid; 726 }; 727 #endif 728 729 struct kioctx_table; 730 struct mm_struct { 731 struct { 732 /* 733 * Fields which are often written to are placed in a separate 734 * cache line. 735 */ 736 struct { 737 /** 738 * @mm_count: The number of references to &struct 739 * mm_struct (@mm_users count as 1). 740 * 741 * Use mmgrab()/mmdrop() to modify. When this drops to 742 * 0, the &struct mm_struct is freed. 743 */ 744 atomic_t mm_count; 745 } ____cacheline_aligned_in_smp; 746 747 struct maple_tree mm_mt; 748 #ifdef CONFIG_MMU 749 unsigned long (*get_unmapped_area) (struct file *filp, 750 unsigned long addr, unsigned long len, 751 unsigned long pgoff, unsigned long flags); 752 #endif 753 unsigned long mmap_base; /* base of mmap area */ 754 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 755 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES 756 /* Base addresses for compatible mmap() */ 757 unsigned long mmap_compat_base; 758 unsigned long mmap_compat_legacy_base; 759 #endif 760 unsigned long task_size; /* size of task vm space */ 761 pgd_t * pgd; 762 763 #ifdef CONFIG_MEMBARRIER 764 /** 765 * @membarrier_state: Flags controlling membarrier behavior. 766 * 767 * This field is close to @pgd to hopefully fit in the same 768 * cache-line, which needs to be touched by switch_mm(). 769 */ 770 atomic_t membarrier_state; 771 #endif 772 773 /** 774 * @mm_users: The number of users including userspace. 775 * 776 * Use mmget()/mmget_not_zero()/mmput() to modify. When this 777 * drops to 0 (i.e. when the task exits and there are no other 778 * temporary reference holders), we also release a reference on 779 * @mm_count (which may then free the &struct mm_struct if 780 * @mm_count also drops to 0). 781 */ 782 atomic_t mm_users; 783 784 #ifdef CONFIG_SCHED_MM_CID 785 /** 786 * @pcpu_cid: Per-cpu current cid. 787 * 788 * Keep track of the currently allocated mm_cid for each cpu. 789 * The per-cpu mm_cid values are serialized by their respective 790 * runqueue locks. 791 */ 792 struct mm_cid __percpu *pcpu_cid; 793 /* 794 * @mm_cid_next_scan: Next mm_cid scan (in jiffies). 795 * 796 * When the next mm_cid scan is due (in jiffies). 797 */ 798 unsigned long mm_cid_next_scan; 799 #endif 800 #ifdef CONFIG_MMU 801 atomic_long_t pgtables_bytes; /* size of all page tables */ 802 #endif 803 int map_count; /* number of VMAs */ 804 805 spinlock_t page_table_lock; /* Protects page tables and some 806 * counters 807 */ 808 /* 809 * With some kernel config, the current mmap_lock's offset 810 * inside 'mm_struct' is at 0x120, which is very optimal, as 811 * its two hot fields 'count' and 'owner' sit in 2 different 812 * cachelines, and when mmap_lock is highly contended, both 813 * of the 2 fields will be accessed frequently, current layout 814 * will help to reduce cache bouncing. 815 * 816 * So please be careful with adding new fields before 817 * mmap_lock, which can easily push the 2 fields into one 818 * cacheline. 819 */ 820 struct rw_semaphore mmap_lock; 821 822 struct list_head mmlist; /* List of maybe swapped mm's. These 823 * are globally strung together off 824 * init_mm.mmlist, and are protected 825 * by mmlist_lock 826 */ 827 #ifdef CONFIG_PER_VMA_LOCK 828 /* 829 * This field has lock-like semantics, meaning it is sometimes 830 * accessed with ACQUIRE/RELEASE semantics. 831 * Roughly speaking, incrementing the sequence number is 832 * equivalent to releasing locks on VMAs; reading the sequence 833 * number can be part of taking a read lock on a VMA. 834 * 835 * Can be modified under write mmap_lock using RELEASE 836 * semantics. 837 * Can be read with no other protection when holding write 838 * mmap_lock. 839 * Can be read with ACQUIRE semantics if not holding write 840 * mmap_lock. 841 */ 842 int mm_lock_seq; 843 #endif 844 845 846 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 847 unsigned long hiwater_vm; /* High-water virtual memory usage */ 848 849 unsigned long total_vm; /* Total pages mapped */ 850 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 851 atomic64_t pinned_vm; /* Refcount permanently increased */ 852 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 853 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 854 unsigned long stack_vm; /* VM_STACK */ 855 unsigned long def_flags; 856 857 /** 858 * @write_protect_seq: Locked when any thread is write 859 * protecting pages mapped by this mm to enforce a later COW, 860 * for instance during page table copying for fork(). 861 */ 862 seqcount_t write_protect_seq; 863 864 spinlock_t arg_lock; /* protect the below fields */ 865 866 unsigned long start_code, end_code, start_data, end_data; 867 unsigned long start_brk, brk, start_stack; 868 unsigned long arg_start, arg_end, env_start, env_end; 869 870 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 871 872 struct percpu_counter rss_stat[NR_MM_COUNTERS]; 873 874 struct linux_binfmt *binfmt; 875 876 /* Architecture-specific MM context */ 877 mm_context_t context; 878 879 unsigned long flags; /* Must use atomic bitops to access */ 880 881 #ifdef CONFIG_AIO 882 spinlock_t ioctx_lock; 883 struct kioctx_table __rcu *ioctx_table; 884 #endif 885 #ifdef CONFIG_MEMCG 886 /* 887 * "owner" points to a task that is regarded as the canonical 888 * user/owner of this mm. All of the following must be true in 889 * order for it to be changed: 890 * 891 * current == mm->owner 892 * current->mm != mm 893 * new_owner->mm == mm 894 * new_owner->alloc_lock is held 895 */ 896 struct task_struct __rcu *owner; 897 #endif 898 struct user_namespace *user_ns; 899 900 /* store ref to file /proc/<pid>/exe symlink points to */ 901 struct file __rcu *exe_file; 902 #ifdef CONFIG_MMU_NOTIFIER 903 struct mmu_notifier_subscriptions *notifier_subscriptions; 904 #endif 905 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 906 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 907 #endif 908 #ifdef CONFIG_NUMA_BALANCING 909 /* 910 * numa_next_scan is the next time that PTEs will be remapped 911 * PROT_NONE to trigger NUMA hinting faults; such faults gather 912 * statistics and migrate pages to new nodes if necessary. 913 */ 914 unsigned long numa_next_scan; 915 916 /* Restart point for scanning and remapping PTEs. */ 917 unsigned long numa_scan_offset; 918 919 /* numa_scan_seq prevents two threads remapping PTEs. */ 920 int numa_scan_seq; 921 #endif 922 /* 923 * An operation with batched TLB flushing is going on. Anything 924 * that can move process memory needs to flush the TLB when 925 * moving a PROT_NONE mapped page. 926 */ 927 atomic_t tlb_flush_pending; 928 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 929 /* See flush_tlb_batched_pending() */ 930 atomic_t tlb_flush_batched; 931 #endif 932 struct uprobes_state uprobes_state; 933 #ifdef CONFIG_PREEMPT_RT 934 struct rcu_head delayed_drop; 935 #endif 936 #ifdef CONFIG_HUGETLB_PAGE 937 atomic_long_t hugetlb_usage; 938 #endif 939 struct work_struct async_put_work; 940 941 #ifdef CONFIG_IOMMU_SVA 942 u32 pasid; 943 #endif 944 #ifdef CONFIG_KSM 945 /* 946 * Represent how many pages of this process are involved in KSM 947 * merging (not including ksm_zero_pages). 948 */ 949 unsigned long ksm_merging_pages; 950 /* 951 * Represent how many pages are checked for ksm merging 952 * including merged and not merged. 953 */ 954 unsigned long ksm_rmap_items; 955 /* 956 * Represent how many empty pages are merged with kernel zero 957 * pages when enabling KSM use_zero_pages. 958 */ 959 unsigned long ksm_zero_pages; 960 #endif /* CONFIG_KSM */ 961 #ifdef CONFIG_LRU_GEN 962 struct { 963 /* this mm_struct is on lru_gen_mm_list */ 964 struct list_head list; 965 /* 966 * Set when switching to this mm_struct, as a hint of 967 * whether it has been used since the last time per-node 968 * page table walkers cleared the corresponding bits. 969 */ 970 unsigned long bitmap; 971 #ifdef CONFIG_MEMCG 972 /* points to the memcg of "owner" above */ 973 struct mem_cgroup *memcg; 974 #endif 975 } lru_gen; 976 #endif /* CONFIG_LRU_GEN */ 977 } __randomize_layout; 978 979 /* 980 * The mm_cpumask needs to be at the end of mm_struct, because it 981 * is dynamically sized based on nr_cpu_ids. 982 */ 983 unsigned long cpu_bitmap[]; 984 }; 985 986 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \ 987 MT_FLAGS_USE_RCU) 988 extern struct mm_struct init_mm; 989 990 /* Pointer magic because the dynamic array size confuses some compilers. */ 991 static inline void mm_init_cpumask(struct mm_struct *mm) 992 { 993 unsigned long cpu_bitmap = (unsigned long)mm; 994 995 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap); 996 cpumask_clear((struct cpumask *)cpu_bitmap); 997 } 998 999 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 1000 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 1001 { 1002 return (struct cpumask *)&mm->cpu_bitmap; 1003 } 1004 1005 #ifdef CONFIG_LRU_GEN 1006 1007 struct lru_gen_mm_list { 1008 /* mm_struct list for page table walkers */ 1009 struct list_head fifo; 1010 /* protects the list above */ 1011 spinlock_t lock; 1012 }; 1013 1014 void lru_gen_add_mm(struct mm_struct *mm); 1015 void lru_gen_del_mm(struct mm_struct *mm); 1016 #ifdef CONFIG_MEMCG 1017 void lru_gen_migrate_mm(struct mm_struct *mm); 1018 #endif 1019 1020 static inline void lru_gen_init_mm(struct mm_struct *mm) 1021 { 1022 INIT_LIST_HEAD(&mm->lru_gen.list); 1023 mm->lru_gen.bitmap = 0; 1024 #ifdef CONFIG_MEMCG 1025 mm->lru_gen.memcg = NULL; 1026 #endif 1027 } 1028 1029 static inline void lru_gen_use_mm(struct mm_struct *mm) 1030 { 1031 /* 1032 * When the bitmap is set, page reclaim knows this mm_struct has been 1033 * used since the last time it cleared the bitmap. So it might be worth 1034 * walking the page tables of this mm_struct to clear the accessed bit. 1035 */ 1036 WRITE_ONCE(mm->lru_gen.bitmap, -1); 1037 } 1038 1039 #else /* !CONFIG_LRU_GEN */ 1040 1041 static inline void lru_gen_add_mm(struct mm_struct *mm) 1042 { 1043 } 1044 1045 static inline void lru_gen_del_mm(struct mm_struct *mm) 1046 { 1047 } 1048 1049 #ifdef CONFIG_MEMCG 1050 static inline void lru_gen_migrate_mm(struct mm_struct *mm) 1051 { 1052 } 1053 #endif 1054 1055 static inline void lru_gen_init_mm(struct mm_struct *mm) 1056 { 1057 } 1058 1059 static inline void lru_gen_use_mm(struct mm_struct *mm) 1060 { 1061 } 1062 1063 #endif /* CONFIG_LRU_GEN */ 1064 1065 struct vma_iterator { 1066 struct ma_state mas; 1067 }; 1068 1069 #define VMA_ITERATOR(name, __mm, __addr) \ 1070 struct vma_iterator name = { \ 1071 .mas = { \ 1072 .tree = &(__mm)->mm_mt, \ 1073 .index = __addr, \ 1074 .node = MAS_START, \ 1075 }, \ 1076 } 1077 1078 static inline void vma_iter_init(struct vma_iterator *vmi, 1079 struct mm_struct *mm, unsigned long addr) 1080 { 1081 mas_init(&vmi->mas, &mm->mm_mt, addr); 1082 } 1083 1084 #ifdef CONFIG_SCHED_MM_CID 1085 1086 enum mm_cid_state { 1087 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */ 1088 MM_CID_LAZY_PUT = (1U << 31), 1089 }; 1090 1091 static inline bool mm_cid_is_unset(int cid) 1092 { 1093 return cid == MM_CID_UNSET; 1094 } 1095 1096 static inline bool mm_cid_is_lazy_put(int cid) 1097 { 1098 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT); 1099 } 1100 1101 static inline bool mm_cid_is_valid(int cid) 1102 { 1103 return !(cid & MM_CID_LAZY_PUT); 1104 } 1105 1106 static inline int mm_cid_set_lazy_put(int cid) 1107 { 1108 return cid | MM_CID_LAZY_PUT; 1109 } 1110 1111 static inline int mm_cid_clear_lazy_put(int cid) 1112 { 1113 return cid & ~MM_CID_LAZY_PUT; 1114 } 1115 1116 /* Accessor for struct mm_struct's cidmask. */ 1117 static inline cpumask_t *mm_cidmask(struct mm_struct *mm) 1118 { 1119 unsigned long cid_bitmap = (unsigned long)mm; 1120 1121 cid_bitmap += offsetof(struct mm_struct, cpu_bitmap); 1122 /* Skip cpu_bitmap */ 1123 cid_bitmap += cpumask_size(); 1124 return (struct cpumask *)cid_bitmap; 1125 } 1126 1127 static inline void mm_init_cid(struct mm_struct *mm) 1128 { 1129 int i; 1130 1131 for_each_possible_cpu(i) { 1132 struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i); 1133 1134 pcpu_cid->cid = MM_CID_UNSET; 1135 pcpu_cid->time = 0; 1136 } 1137 cpumask_clear(mm_cidmask(mm)); 1138 } 1139 1140 static inline int mm_alloc_cid(struct mm_struct *mm) 1141 { 1142 mm->pcpu_cid = alloc_percpu(struct mm_cid); 1143 if (!mm->pcpu_cid) 1144 return -ENOMEM; 1145 mm_init_cid(mm); 1146 return 0; 1147 } 1148 1149 static inline void mm_destroy_cid(struct mm_struct *mm) 1150 { 1151 free_percpu(mm->pcpu_cid); 1152 mm->pcpu_cid = NULL; 1153 } 1154 1155 static inline unsigned int mm_cid_size(void) 1156 { 1157 return cpumask_size(); 1158 } 1159 #else /* CONFIG_SCHED_MM_CID */ 1160 static inline void mm_init_cid(struct mm_struct *mm) { } 1161 static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; } 1162 static inline void mm_destroy_cid(struct mm_struct *mm) { } 1163 static inline unsigned int mm_cid_size(void) 1164 { 1165 return 0; 1166 } 1167 #endif /* CONFIG_SCHED_MM_CID */ 1168 1169 struct mmu_gather; 1170 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); 1171 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); 1172 extern void tlb_finish_mmu(struct mmu_gather *tlb); 1173 1174 struct vm_fault; 1175 1176 /** 1177 * typedef vm_fault_t - Return type for page fault handlers. 1178 * 1179 * Page fault handlers return a bitmask of %VM_FAULT values. 1180 */ 1181 typedef __bitwise unsigned int vm_fault_t; 1182 1183 /** 1184 * enum vm_fault_reason - Page fault handlers return a bitmask of 1185 * these values to tell the core VM what happened when handling the 1186 * fault. Used to decide whether a process gets delivered SIGBUS or 1187 * just gets major/minor fault counters bumped up. 1188 * 1189 * @VM_FAULT_OOM: Out Of Memory 1190 * @VM_FAULT_SIGBUS: Bad access 1191 * @VM_FAULT_MAJOR: Page read from storage 1192 * @VM_FAULT_HWPOISON: Hit poisoned small page 1193 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded 1194 * in upper bits 1195 * @VM_FAULT_SIGSEGV: segmentation fault 1196 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page 1197 * @VM_FAULT_LOCKED: ->fault locked the returned page 1198 * @VM_FAULT_RETRY: ->fault blocked, must retry 1199 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small 1200 * @VM_FAULT_DONE_COW: ->fault has fully handled COW 1201 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs 1202 * fsync() to complete (for synchronous page faults 1203 * in DAX) 1204 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released 1205 * @VM_FAULT_HINDEX_MASK: mask HINDEX value 1206 * 1207 */ 1208 enum vm_fault_reason { 1209 VM_FAULT_OOM = (__force vm_fault_t)0x000001, 1210 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, 1211 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, 1212 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, 1213 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, 1214 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, 1215 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, 1216 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, 1217 VM_FAULT_RETRY = (__force vm_fault_t)0x000400, 1218 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, 1219 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, 1220 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, 1221 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000, 1222 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, 1223 }; 1224 1225 /* Encode hstate index for a hwpoisoned large page */ 1226 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) 1227 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf) 1228 1229 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ 1230 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ 1231 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) 1232 1233 #define VM_FAULT_RESULT_TRACE \ 1234 { VM_FAULT_OOM, "OOM" }, \ 1235 { VM_FAULT_SIGBUS, "SIGBUS" }, \ 1236 { VM_FAULT_MAJOR, "MAJOR" }, \ 1237 { VM_FAULT_HWPOISON, "HWPOISON" }, \ 1238 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ 1239 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ 1240 { VM_FAULT_NOPAGE, "NOPAGE" }, \ 1241 { VM_FAULT_LOCKED, "LOCKED" }, \ 1242 { VM_FAULT_RETRY, "RETRY" }, \ 1243 { VM_FAULT_FALLBACK, "FALLBACK" }, \ 1244 { VM_FAULT_DONE_COW, "DONE_COW" }, \ 1245 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \ 1246 { VM_FAULT_COMPLETED, "COMPLETED" } 1247 1248 struct vm_special_mapping { 1249 const char *name; /* The name, e.g. "[vdso]". */ 1250 1251 /* 1252 * If .fault is not provided, this points to a 1253 * NULL-terminated array of pages that back the special mapping. 1254 * 1255 * This must not be NULL unless .fault is provided. 1256 */ 1257 struct page **pages; 1258 1259 /* 1260 * If non-NULL, then this is called to resolve page faults 1261 * on the special mapping. If used, .pages is not checked. 1262 */ 1263 vm_fault_t (*fault)(const struct vm_special_mapping *sm, 1264 struct vm_area_struct *vma, 1265 struct vm_fault *vmf); 1266 1267 int (*mremap)(const struct vm_special_mapping *sm, 1268 struct vm_area_struct *new_vma); 1269 }; 1270 1271 enum tlb_flush_reason { 1272 TLB_FLUSH_ON_TASK_SWITCH, 1273 TLB_REMOTE_SHOOTDOWN, 1274 TLB_LOCAL_SHOOTDOWN, 1275 TLB_LOCAL_MM_SHOOTDOWN, 1276 TLB_REMOTE_SEND_IPI, 1277 NR_TLB_FLUSH_REASONS, 1278 }; 1279 1280 /** 1281 * enum fault_flag - Fault flag definitions. 1282 * @FAULT_FLAG_WRITE: Fault was a write fault. 1283 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE. 1284 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked. 1285 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying. 1286 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region. 1287 * @FAULT_FLAG_TRIED: The fault has been tried once. 1288 * @FAULT_FLAG_USER: The fault originated in userspace. 1289 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. 1290 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. 1291 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. 1292 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a 1293 * COW mapping, making sure that an exclusive anon page is 1294 * mapped after the fault. 1295 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached. 1296 * We should only access orig_pte if this flag set. 1297 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock. 1298 * 1299 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify 1300 * whether we would allow page faults to retry by specifying these two 1301 * fault flags correctly. Currently there can be three legal combinations: 1302 * 1303 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and 1304 * this is the first try 1305 * 1306 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and 1307 * we've already tried at least once 1308 * 1309 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry 1310 * 1311 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never 1312 * be used. Note that page faults can be allowed to retry for multiple times, 1313 * in which case we'll have an initial fault with flags (a) then later on 1314 * continuous faults with flags (b). We should always try to detect pending 1315 * signals before a retry to make sure the continuous page faults can still be 1316 * interrupted if necessary. 1317 * 1318 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal. 1319 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when 1320 * applied to mappings that are not COW mappings. 1321 */ 1322 enum fault_flag { 1323 FAULT_FLAG_WRITE = 1 << 0, 1324 FAULT_FLAG_MKWRITE = 1 << 1, 1325 FAULT_FLAG_ALLOW_RETRY = 1 << 2, 1326 FAULT_FLAG_RETRY_NOWAIT = 1 << 3, 1327 FAULT_FLAG_KILLABLE = 1 << 4, 1328 FAULT_FLAG_TRIED = 1 << 5, 1329 FAULT_FLAG_USER = 1 << 6, 1330 FAULT_FLAG_REMOTE = 1 << 7, 1331 FAULT_FLAG_INSTRUCTION = 1 << 8, 1332 FAULT_FLAG_INTERRUPTIBLE = 1 << 9, 1333 FAULT_FLAG_UNSHARE = 1 << 10, 1334 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11, 1335 FAULT_FLAG_VMA_LOCK = 1 << 12, 1336 }; 1337 1338 typedef unsigned int __bitwise zap_flags_t; 1339 1340 /* 1341 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each 1342 * other. Here is what they mean, and how to use them: 1343 * 1344 * 1345 * FIXME: For pages which are part of a filesystem, mappings are subject to the 1346 * lifetime enforced by the filesystem and we need guarantees that longterm 1347 * users like RDMA and V4L2 only establish mappings which coordinate usage with 1348 * the filesystem. Ideas for this coordination include revoking the longterm 1349 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was 1350 * added after the problem with filesystems was found FS DAX VMAs are 1351 * specifically failed. Filesystem pages are still subject to bugs and use of 1352 * FOLL_LONGTERM should be avoided on those pages. 1353 * 1354 * In the CMA case: long term pins in a CMA region would unnecessarily fragment 1355 * that region. And so, CMA attempts to migrate the page before pinning, when 1356 * FOLL_LONGTERM is specified. 1357 * 1358 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount, 1359 * but an additional pin counting system) will be invoked. This is intended for 1360 * anything that gets a page reference and then touches page data (for example, 1361 * Direct IO). This lets the filesystem know that some non-file-system entity is 1362 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages 1363 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by 1364 * a call to unpin_user_page(). 1365 * 1366 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different 1367 * and separate refcounting mechanisms, however, and that means that each has 1368 * its own acquire and release mechanisms: 1369 * 1370 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release. 1371 * 1372 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release. 1373 * 1374 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call. 1375 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based 1376 * calls applied to them, and that's perfectly OK. This is a constraint on the 1377 * callers, not on the pages.) 1378 * 1379 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never 1380 * directly by the caller. That's in order to help avoid mismatches when 1381 * releasing pages: get_user_pages*() pages must be released via put_page(), 1382 * while pin_user_pages*() pages must be released via unpin_user_page(). 1383 * 1384 * Please see Documentation/core-api/pin_user_pages.rst for more information. 1385 */ 1386 1387 enum { 1388 /* check pte is writable */ 1389 FOLL_WRITE = 1 << 0, 1390 /* do get_page on page */ 1391 FOLL_GET = 1 << 1, 1392 /* give error on hole if it would be zero */ 1393 FOLL_DUMP = 1 << 2, 1394 /* get_user_pages read/write w/o permission */ 1395 FOLL_FORCE = 1 << 3, 1396 /* 1397 * if a disk transfer is needed, start the IO and return without waiting 1398 * upon it 1399 */ 1400 FOLL_NOWAIT = 1 << 4, 1401 /* do not fault in pages */ 1402 FOLL_NOFAULT = 1 << 5, 1403 /* check page is hwpoisoned */ 1404 FOLL_HWPOISON = 1 << 6, 1405 /* don't do file mappings */ 1406 FOLL_ANON = 1 << 7, 1407 /* 1408 * FOLL_LONGTERM indicates that the page will be held for an indefinite 1409 * time period _often_ under userspace control. This is in contrast to 1410 * iov_iter_get_pages(), whose usages are transient. 1411 */ 1412 FOLL_LONGTERM = 1 << 8, 1413 /* split huge pmd before returning */ 1414 FOLL_SPLIT_PMD = 1 << 9, 1415 /* allow returning PCI P2PDMA pages */ 1416 FOLL_PCI_P2PDMA = 1 << 10, 1417 /* allow interrupts from generic signals */ 1418 FOLL_INTERRUPTIBLE = 1 << 11, 1419 /* 1420 * Always honor (trigger) NUMA hinting faults. 1421 * 1422 * FOLL_WRITE implicitly honors NUMA hinting faults because a 1423 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE 1424 * apply). get_user_pages_fast_only() always implicitly honors NUMA 1425 * hinting faults. 1426 */ 1427 FOLL_HONOR_NUMA_FAULT = 1 << 12, 1428 1429 /* See also internal only FOLL flags in mm/internal.h */ 1430 }; 1431 1432 #endif /* _LINUX_MM_TYPES_H */ 1433