1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_MM_TYPES_H 3 #define _LINUX_MM_TYPES_H 4 5 #include <linux/mm_types_task.h> 6 7 #include <linux/auxvec.h> 8 #include <linux/kref.h> 9 #include <linux/list.h> 10 #include <linux/spinlock.h> 11 #include <linux/rbtree.h> 12 #include <linux/maple_tree.h> 13 #include <linux/rwsem.h> 14 #include <linux/completion.h> 15 #include <linux/cpumask.h> 16 #include <linux/uprobes.h> 17 #include <linux/rcupdate.h> 18 #include <linux/page-flags-layout.h> 19 #include <linux/workqueue.h> 20 #include <linux/seqlock.h> 21 #include <linux/percpu_counter.h> 22 23 #include <asm/mmu.h> 24 25 #ifndef AT_VECTOR_SIZE_ARCH 26 #define AT_VECTOR_SIZE_ARCH 0 27 #endif 28 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) 29 30 #define INIT_PASID 0 31 32 struct address_space; 33 struct mem_cgroup; 34 35 /* 36 * Each physical page in the system has a struct page associated with 37 * it to keep track of whatever it is we are using the page for at the 38 * moment. Note that we have no way to track which tasks are using 39 * a page, though if it is a pagecache page, rmap structures can tell us 40 * who is mapping it. 41 * 42 * If you allocate the page using alloc_pages(), you can use some of the 43 * space in struct page for your own purposes. The five words in the main 44 * union are available, except for bit 0 of the first word which must be 45 * kept clear. Many users use this word to store a pointer to an object 46 * which is guaranteed to be aligned. If you use the same storage as 47 * page->mapping, you must restore it to NULL before freeing the page. 48 * 49 * The mapcount field must not be used for own purposes. 50 * 51 * If you want to use the refcount field, it must be used in such a way 52 * that other CPUs temporarily incrementing and then decrementing the 53 * refcount does not cause problems. On receiving the page from 54 * alloc_pages(), the refcount will be positive. 55 * 56 * If you allocate pages of order > 0, you can use some of the fields 57 * in each subpage, but you may need to restore some of their values 58 * afterwards. 59 * 60 * SLUB uses cmpxchg_double() to atomically update its freelist and counters. 61 * That requires that freelist & counters in struct slab be adjacent and 62 * double-word aligned. Because struct slab currently just reinterprets the 63 * bits of struct page, we align all struct pages to double-word boundaries, 64 * and ensure that 'freelist' is aligned within struct slab. 65 */ 66 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 67 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) 68 #else 69 #define _struct_page_alignment __aligned(sizeof(unsigned long)) 70 #endif 71 72 struct page { 73 unsigned long flags; /* Atomic flags, some possibly 74 * updated asynchronously */ 75 /* 76 * Five words (20/40 bytes) are available in this union. 77 * WARNING: bit 0 of the first word is used for PageTail(). That 78 * means the other users of this union MUST NOT use the bit to 79 * avoid collision and false-positive PageTail(). 80 */ 81 union { 82 struct { /* Page cache and anonymous pages */ 83 /** 84 * @lru: Pageout list, eg. active_list protected by 85 * lruvec->lru_lock. Sometimes used as a generic list 86 * by the page owner. 87 */ 88 union { 89 struct list_head lru; 90 91 /* Or, for the Unevictable "LRU list" slot */ 92 struct { 93 /* Always even, to negate PageTail */ 94 void *__filler; 95 /* Count page's or folio's mlocks */ 96 unsigned int mlock_count; 97 }; 98 99 /* Or, free page */ 100 struct list_head buddy_list; 101 struct list_head pcp_list; 102 }; 103 /* See page-flags.h for PAGE_MAPPING_FLAGS */ 104 struct address_space *mapping; 105 union { 106 pgoff_t index; /* Our offset within mapping. */ 107 unsigned long share; /* share count for fsdax */ 108 }; 109 /** 110 * @private: Mapping-private opaque data. 111 * Usually used for buffer_heads if PagePrivate. 112 * Used for swp_entry_t if PageSwapCache. 113 * Indicates order in the buddy system if PageBuddy. 114 */ 115 unsigned long private; 116 }; 117 struct { /* page_pool used by netstack */ 118 /** 119 * @pp_magic: magic value to avoid recycling non 120 * page_pool allocated pages. 121 */ 122 unsigned long pp_magic; 123 struct page_pool *pp; 124 unsigned long _pp_mapping_pad; 125 unsigned long dma_addr; 126 atomic_long_t pp_ref_count; 127 }; 128 struct { /* Tail pages of compound page */ 129 unsigned long compound_head; /* Bit zero is set */ 130 }; 131 struct { /* ZONE_DEVICE pages */ 132 /** @pgmap: Points to the hosting device page map. */ 133 struct dev_pagemap *pgmap; 134 void *zone_device_data; 135 /* 136 * ZONE_DEVICE private pages are counted as being 137 * mapped so the next 3 words hold the mapping, index, 138 * and private fields from the source anonymous or 139 * page cache page while the page is migrated to device 140 * private memory. 141 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also 142 * use the mapping, index, and private fields when 143 * pmem backed DAX files are mapped. 144 */ 145 }; 146 147 /** @rcu_head: You can use this to free a page by RCU. */ 148 struct rcu_head rcu_head; 149 }; 150 151 union { /* This union is 4 bytes in size. */ 152 /* 153 * For head pages of typed folios, the value stored here 154 * allows for determining what this page is used for. The 155 * tail pages of typed folios will not store a type 156 * (page_type == _mapcount == -1). 157 * 158 * See page-flags.h for a list of page types which are currently 159 * stored here. 160 * 161 * Owners of typed folios may reuse the lower 16 bit of the 162 * head page page_type field after setting the page type, 163 * but must reset these 16 bit to -1 before clearing the 164 * page type. 165 */ 166 unsigned int page_type; 167 168 /* 169 * For pages that are part of non-typed folios for which mappings 170 * are tracked via the RMAP, encodes the number of times this page 171 * is directly referenced by a page table. 172 * 173 * Note that the mapcount is always initialized to -1, so that 174 * transitions both from it and to it can be tracked, using 175 * atomic_inc_and_test() and atomic_add_negative(-1). 176 */ 177 atomic_t _mapcount; 178 }; 179 180 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */ 181 atomic_t _refcount; 182 183 #ifdef CONFIG_SLAB_OBJ_EXT 184 unsigned long memcg_data; 185 #endif 186 187 /* 188 * On machines where all RAM is mapped into kernel address space, 189 * we can simply calculate the virtual address. On machines with 190 * highmem some memory is mapped into kernel virtual memory 191 * dynamically, so we need a place to store that address. 192 * Note that this field could be 16 bits on x86 ... ;) 193 * 194 * Architectures with slow multiplication can define 195 * WANT_PAGE_VIRTUAL in asm/page.h 196 */ 197 #if defined(WANT_PAGE_VIRTUAL) 198 void *virtual; /* Kernel virtual address (NULL if 199 not kmapped, ie. highmem) */ 200 #endif /* WANT_PAGE_VIRTUAL */ 201 202 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 203 int _last_cpupid; 204 #endif 205 206 #ifdef CONFIG_KMSAN 207 /* 208 * KMSAN metadata for this page: 209 * - shadow page: every bit indicates whether the corresponding 210 * bit of the original page is initialized (0) or not (1); 211 * - origin page: every 4 bytes contain an id of the stack trace 212 * where the uninitialized value was created. 213 */ 214 struct page *kmsan_shadow; 215 struct page *kmsan_origin; 216 #endif 217 } _struct_page_alignment; 218 219 /* 220 * struct encoded_page - a nonexistent type marking this pointer 221 * 222 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but 223 * with the low bits of the pointer indicating extra context-dependent 224 * information. Only used in mmu_gather handling, and this acts as a type 225 * system check on that use. 226 * 227 * We only really have two guaranteed bits in general, although you could 228 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 229 * for more. 230 * 231 * Use the supplied helper functions to endcode/decode the pointer and bits. 232 */ 233 struct encoded_page; 234 235 #define ENCODED_PAGE_BITS 3ul 236 237 /* Perform rmap removal after we have flushed the TLB. */ 238 #define ENCODED_PAGE_BIT_DELAY_RMAP 1ul 239 240 /* 241 * The next item in an encoded_page array is the "nr_pages" argument, specifying 242 * the number of consecutive pages starting from this page, that all belong to 243 * the same folio. For example, "nr_pages" corresponds to the number of folio 244 * references that must be dropped. If this bit is not set, "nr_pages" is 245 * implicitly 1. 246 */ 247 #define ENCODED_PAGE_BIT_NR_PAGES_NEXT 2ul 248 249 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags) 250 { 251 BUILD_BUG_ON(flags > ENCODED_PAGE_BITS); 252 return (struct encoded_page *)(flags | (unsigned long)page); 253 } 254 255 static inline unsigned long encoded_page_flags(struct encoded_page *page) 256 { 257 return ENCODED_PAGE_BITS & (unsigned long)page; 258 } 259 260 static inline struct page *encoded_page_ptr(struct encoded_page *page) 261 { 262 return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page); 263 } 264 265 static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr) 266 { 267 VM_WARN_ON_ONCE((nr << 2) >> 2 != nr); 268 return (struct encoded_page *)(nr << 2); 269 } 270 271 static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page) 272 { 273 return ((unsigned long)page) >> 2; 274 } 275 276 /* 277 * A swap entry has to fit into a "unsigned long", as the entry is hidden 278 * in the "index" field of the swapper address space. 279 */ 280 typedef struct { 281 unsigned long val; 282 } swp_entry_t; 283 284 /** 285 * struct folio - Represents a contiguous set of bytes. 286 * @flags: Identical to the page flags. 287 * @lru: Least Recently Used list; tracks how recently this folio was used. 288 * @mlock_count: Number of times this folio has been pinned by mlock(). 289 * @mapping: The file this page belongs to, or refers to the anon_vma for 290 * anonymous memory. 291 * @index: Offset within the file, in units of pages. For anonymous memory, 292 * this is the index from the beginning of the mmap. 293 * @private: Filesystem per-folio data (see folio_attach_private()). 294 * @swap: Used for swp_entry_t if folio_test_swapcache(). 295 * @_mapcount: Do not access this member directly. Use folio_mapcount() to 296 * find out how many times this folio is mapped by userspace. 297 * @_refcount: Do not access this member directly. Use folio_ref_count() 298 * to find how many references there are to this folio. 299 * @memcg_data: Memory Control Group data. 300 * @virtual: Virtual address in the kernel direct map. 301 * @_last_cpupid: IDs of last CPU and last process that accessed the folio. 302 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount(). 303 * @_large_mapcount: Do not use directly, call folio_mapcount(). 304 * @_nr_pages_mapped: Do not use outside of rmap and debug code. 305 * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). 306 * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). 307 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h. 308 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h. 309 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h. 310 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head(). 311 * @_deferred_list: Folios to be split under memory pressure. 312 * 313 * A folio is a physically, virtually and logically contiguous set 314 * of bytes. It is a power-of-two in size, and it is aligned to that 315 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is 316 * in the page cache, it is at a file offset which is a multiple of that 317 * power-of-two. It may be mapped into userspace at an address which is 318 * at an arbitrary page offset, but its kernel virtual address is aligned 319 * to its size. 320 */ 321 struct folio { 322 /* private: don't document the anon union */ 323 union { 324 struct { 325 /* public: */ 326 unsigned long flags; 327 union { 328 struct list_head lru; 329 /* private: avoid cluttering the output */ 330 struct { 331 void *__filler; 332 /* public: */ 333 unsigned int mlock_count; 334 /* private: */ 335 }; 336 /* public: */ 337 }; 338 struct address_space *mapping; 339 pgoff_t index; 340 union { 341 void *private; 342 swp_entry_t swap; 343 }; 344 atomic_t _mapcount; 345 atomic_t _refcount; 346 #ifdef CONFIG_SLAB_OBJ_EXT 347 unsigned long memcg_data; 348 #endif 349 #if defined(WANT_PAGE_VIRTUAL) 350 void *virtual; 351 #endif 352 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 353 int _last_cpupid; 354 #endif 355 /* private: the union with struct page is transitional */ 356 }; 357 struct page page; 358 }; 359 union { 360 struct { 361 unsigned long _flags_1; 362 unsigned long _head_1; 363 /* public: */ 364 atomic_t _large_mapcount; 365 atomic_t _entire_mapcount; 366 atomic_t _nr_pages_mapped; 367 atomic_t _pincount; 368 #ifdef CONFIG_64BIT 369 unsigned int _folio_nr_pages; 370 #endif 371 /* private: the union with struct page is transitional */ 372 }; 373 struct page __page_1; 374 }; 375 union { 376 struct { 377 unsigned long _flags_2; 378 unsigned long _head_2; 379 /* public: */ 380 void *_hugetlb_subpool; 381 void *_hugetlb_cgroup; 382 void *_hugetlb_cgroup_rsvd; 383 void *_hugetlb_hwpoison; 384 /* private: the union with struct page is transitional */ 385 }; 386 struct { 387 unsigned long _flags_2a; 388 unsigned long _head_2a; 389 /* public: */ 390 struct list_head _deferred_list; 391 /* private: the union with struct page is transitional */ 392 }; 393 struct page __page_2; 394 }; 395 }; 396 397 #define FOLIO_MATCH(pg, fl) \ 398 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl)) 399 FOLIO_MATCH(flags, flags); 400 FOLIO_MATCH(lru, lru); 401 FOLIO_MATCH(mapping, mapping); 402 FOLIO_MATCH(compound_head, lru); 403 FOLIO_MATCH(index, index); 404 FOLIO_MATCH(private, private); 405 FOLIO_MATCH(_mapcount, _mapcount); 406 FOLIO_MATCH(_refcount, _refcount); 407 #ifdef CONFIG_MEMCG 408 FOLIO_MATCH(memcg_data, memcg_data); 409 #endif 410 #if defined(WANT_PAGE_VIRTUAL) 411 FOLIO_MATCH(virtual, virtual); 412 #endif 413 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 414 FOLIO_MATCH(_last_cpupid, _last_cpupid); 415 #endif 416 #undef FOLIO_MATCH 417 #define FOLIO_MATCH(pg, fl) \ 418 static_assert(offsetof(struct folio, fl) == \ 419 offsetof(struct page, pg) + sizeof(struct page)) 420 FOLIO_MATCH(flags, _flags_1); 421 FOLIO_MATCH(compound_head, _head_1); 422 #undef FOLIO_MATCH 423 #define FOLIO_MATCH(pg, fl) \ 424 static_assert(offsetof(struct folio, fl) == \ 425 offsetof(struct page, pg) + 2 * sizeof(struct page)) 426 FOLIO_MATCH(flags, _flags_2); 427 FOLIO_MATCH(compound_head, _head_2); 428 FOLIO_MATCH(flags, _flags_2a); 429 FOLIO_MATCH(compound_head, _head_2a); 430 #undef FOLIO_MATCH 431 432 /** 433 * struct ptdesc - Memory descriptor for page tables. 434 * @__page_flags: Same as page flags. Powerpc only. 435 * @pt_rcu_head: For freeing page table pages. 436 * @pt_list: List of used page tables. Used for s390 and x86. 437 * @_pt_pad_1: Padding that aliases with page's compound head. 438 * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs. 439 * @__page_mapping: Aliases with page->mapping. Unused for page tables. 440 * @pt_index: Used for s390 gmap. 441 * @pt_mm: Used for x86 pgds. 442 * @pt_frag_refcount: For fragmented page table tracking. Powerpc only. 443 * @_pt_pad_2: Padding to ensure proper alignment. 444 * @ptl: Lock for the page table. 445 * @__page_type: Same as page->page_type. Unused for page tables. 446 * @__page_refcount: Same as page refcount. 447 * @pt_memcg_data: Memcg data. Tracked for page tables here. 448 * 449 * This struct overlays struct page for now. Do not modify without a good 450 * understanding of the issues. 451 */ 452 struct ptdesc { 453 unsigned long __page_flags; 454 455 union { 456 struct rcu_head pt_rcu_head; 457 struct list_head pt_list; 458 struct { 459 unsigned long _pt_pad_1; 460 pgtable_t pmd_huge_pte; 461 }; 462 }; 463 unsigned long __page_mapping; 464 465 union { 466 pgoff_t pt_index; 467 struct mm_struct *pt_mm; 468 atomic_t pt_frag_refcount; 469 }; 470 471 union { 472 unsigned long _pt_pad_2; 473 #if ALLOC_SPLIT_PTLOCKS 474 spinlock_t *ptl; 475 #else 476 spinlock_t ptl; 477 #endif 478 }; 479 unsigned int __page_type; 480 atomic_t __page_refcount; 481 #ifdef CONFIG_MEMCG 482 unsigned long pt_memcg_data; 483 #endif 484 }; 485 486 #define TABLE_MATCH(pg, pt) \ 487 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt)) 488 TABLE_MATCH(flags, __page_flags); 489 TABLE_MATCH(compound_head, pt_list); 490 TABLE_MATCH(compound_head, _pt_pad_1); 491 TABLE_MATCH(mapping, __page_mapping); 492 TABLE_MATCH(index, pt_index); 493 TABLE_MATCH(rcu_head, pt_rcu_head); 494 TABLE_MATCH(page_type, __page_type); 495 TABLE_MATCH(_refcount, __page_refcount); 496 #ifdef CONFIG_MEMCG 497 TABLE_MATCH(memcg_data, pt_memcg_data); 498 #endif 499 #undef TABLE_MATCH 500 static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); 501 502 #define ptdesc_page(pt) (_Generic((pt), \ 503 const struct ptdesc *: (const struct page *)(pt), \ 504 struct ptdesc *: (struct page *)(pt))) 505 506 #define ptdesc_folio(pt) (_Generic((pt), \ 507 const struct ptdesc *: (const struct folio *)(pt), \ 508 struct ptdesc *: (struct folio *)(pt))) 509 510 #define page_ptdesc(p) (_Generic((p), \ 511 const struct page *: (const struct ptdesc *)(p), \ 512 struct page *: (struct ptdesc *)(p))) 513 514 /* 515 * Used for sizing the vmemmap region on some architectures 516 */ 517 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) 518 519 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) 520 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) 521 522 /* 523 * page_private can be used on tail pages. However, PagePrivate is only 524 * checked by the VM on the head page. So page_private on the tail pages 525 * should be used for data that's ancillary to the head page (eg attaching 526 * buffer heads to tail pages after attaching buffer heads to the head page) 527 */ 528 #define page_private(page) ((page)->private) 529 530 static inline void set_page_private(struct page *page, unsigned long private) 531 { 532 page->private = private; 533 } 534 535 static inline void *folio_get_private(struct folio *folio) 536 { 537 return folio->private; 538 } 539 540 struct page_frag_cache { 541 void * va; 542 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) 543 __u16 offset; 544 __u16 size; 545 #else 546 __u32 offset; 547 #endif 548 /* we maintain a pagecount bias, so that we dont dirty cache line 549 * containing page->_refcount every time we allocate a fragment. 550 */ 551 unsigned int pagecnt_bias; 552 bool pfmemalloc; 553 }; 554 555 typedef unsigned long vm_flags_t; 556 557 /* 558 * A region containing a mapping of a non-memory backed file under NOMMU 559 * conditions. These are held in a global tree and are pinned by the VMAs that 560 * map parts of them. 561 */ 562 struct vm_region { 563 struct rb_node vm_rb; /* link in global region tree */ 564 vm_flags_t vm_flags; /* VMA vm_flags */ 565 unsigned long vm_start; /* start address of region */ 566 unsigned long vm_end; /* region initialised to here */ 567 unsigned long vm_top; /* region allocated to here */ 568 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 569 struct file *vm_file; /* the backing file or NULL */ 570 571 int vm_usage; /* region usage count (access under nommu_region_sem) */ 572 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 573 * this region */ 574 }; 575 576 #ifdef CONFIG_USERFAULTFD 577 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 578 struct vm_userfaultfd_ctx { 579 struct userfaultfd_ctx *ctx; 580 }; 581 #else /* CONFIG_USERFAULTFD */ 582 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 583 struct vm_userfaultfd_ctx {}; 584 #endif /* CONFIG_USERFAULTFD */ 585 586 struct anon_vma_name { 587 struct kref kref; 588 /* The name needs to be at the end because it is dynamically sized. */ 589 char name[]; 590 }; 591 592 #ifdef CONFIG_ANON_VMA_NAME 593 /* 594 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should 595 * either keep holding the lock while using the returned pointer or it should 596 * raise anon_vma_name refcount before releasing the lock. 597 */ 598 struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); 599 struct anon_vma_name *anon_vma_name_alloc(const char *name); 600 void anon_vma_name_free(struct kref *kref); 601 #else /* CONFIG_ANON_VMA_NAME */ 602 static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) 603 { 604 return NULL; 605 } 606 607 static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) 608 { 609 return NULL; 610 } 611 #endif 612 613 struct vma_lock { 614 struct rw_semaphore lock; 615 }; 616 617 struct vma_numab_state { 618 /* 619 * Initialised as time in 'jiffies' after which VMA 620 * should be scanned. Delays first scan of new VMA by at 621 * least sysctl_numa_balancing_scan_delay: 622 */ 623 unsigned long next_scan; 624 625 /* 626 * Time in jiffies when pids_active[] is reset to 627 * detect phase change behaviour: 628 */ 629 unsigned long pids_active_reset; 630 631 /* 632 * Approximate tracking of PIDs that trapped a NUMA hinting 633 * fault. May produce false positives due to hash collisions. 634 * 635 * [0] Previous PID tracking 636 * [1] Current PID tracking 637 * 638 * Window moves after next_pid_reset has expired approximately 639 * every VMA_PID_RESET_PERIOD jiffies: 640 */ 641 unsigned long pids_active[2]; 642 643 /* MM scan sequence ID when scan first started after VMA creation */ 644 int start_scan_seq; 645 646 /* 647 * MM scan sequence ID when the VMA was last completely scanned. 648 * A VMA is not eligible for scanning if prev_scan_seq == numa_scan_seq 649 */ 650 int prev_scan_seq; 651 }; 652 653 /* 654 * This struct describes a virtual memory area. There is one of these 655 * per VM-area/task. A VM area is any part of the process virtual memory 656 * space that has a special rule for the page-fault handlers (ie a shared 657 * library, the executable area etc). 658 */ 659 struct vm_area_struct { 660 /* The first cache line has the info for VMA tree walking. */ 661 662 union { 663 struct { 664 /* VMA covers [vm_start; vm_end) addresses within mm */ 665 unsigned long vm_start; 666 unsigned long vm_end; 667 }; 668 #ifdef CONFIG_PER_VMA_LOCK 669 struct rcu_head vm_rcu; /* Used for deferred freeing. */ 670 #endif 671 }; 672 673 struct mm_struct *vm_mm; /* The address space we belong to. */ 674 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 675 676 /* 677 * Flags, see mm.h. 678 * To modify use vm_flags_{init|reset|set|clear|mod} functions. 679 */ 680 union { 681 const vm_flags_t vm_flags; 682 vm_flags_t __private __vm_flags; 683 }; 684 685 #ifdef CONFIG_PER_VMA_LOCK 686 /* Flag to indicate areas detached from the mm->mm_mt tree */ 687 bool detached; 688 689 /* 690 * Can only be written (using WRITE_ONCE()) while holding both: 691 * - mmap_lock (in write mode) 692 * - vm_lock->lock (in write mode) 693 * Can be read reliably while holding one of: 694 * - mmap_lock (in read or write mode) 695 * - vm_lock->lock (in read or write mode) 696 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout 697 * while holding nothing (except RCU to keep the VMA struct allocated). 698 * 699 * This sequence counter is explicitly allowed to overflow; sequence 700 * counter reuse can only lead to occasional unnecessary use of the 701 * slowpath. 702 */ 703 int vm_lock_seq; 704 struct vma_lock *vm_lock; 705 #endif 706 707 /* 708 * For areas with an address space and backing store, 709 * linkage into the address_space->i_mmap interval tree. 710 * 711 */ 712 struct { 713 struct rb_node rb; 714 unsigned long rb_subtree_last; 715 } shared; 716 717 /* 718 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 719 * list, after a COW of one of the file pages. A MAP_SHARED vma 720 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 721 * or brk vma (with NULL file) can only be in an anon_vma list. 722 */ 723 struct list_head anon_vma_chain; /* Serialized by mmap_lock & 724 * page_table_lock */ 725 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 726 727 /* Function pointers to deal with this struct. */ 728 const struct vm_operations_struct *vm_ops; 729 730 /* Information about our backing store: */ 731 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 732 units */ 733 struct file * vm_file; /* File we map to (can be NULL). */ 734 void * vm_private_data; /* was vm_pte (shared mem) */ 735 736 #ifdef CONFIG_ANON_VMA_NAME 737 /* 738 * For private and shared anonymous mappings, a pointer to a null 739 * terminated string containing the name given to the vma, or NULL if 740 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access. 741 */ 742 struct anon_vma_name *anon_name; 743 #endif 744 #ifdef CONFIG_SWAP 745 atomic_long_t swap_readahead_info; 746 #endif 747 #ifndef CONFIG_MMU 748 struct vm_region *vm_region; /* NOMMU mapping region */ 749 #endif 750 #ifdef CONFIG_NUMA 751 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 752 #endif 753 #ifdef CONFIG_NUMA_BALANCING 754 struct vma_numab_state *numab_state; /* NUMA Balancing state */ 755 #endif 756 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 757 } __randomize_layout; 758 759 #ifdef CONFIG_NUMA 760 #define vma_policy(vma) ((vma)->vm_policy) 761 #else 762 #define vma_policy(vma) NULL 763 #endif 764 765 #ifdef CONFIG_SCHED_MM_CID 766 struct mm_cid { 767 u64 time; 768 int cid; 769 }; 770 #endif 771 772 struct kioctx_table; 773 struct iommu_mm_data; 774 struct mm_struct { 775 struct { 776 /* 777 * Fields which are often written to are placed in a separate 778 * cache line. 779 */ 780 struct { 781 /** 782 * @mm_count: The number of references to &struct 783 * mm_struct (@mm_users count as 1). 784 * 785 * Use mmgrab()/mmdrop() to modify. When this drops to 786 * 0, the &struct mm_struct is freed. 787 */ 788 atomic_t mm_count; 789 } ____cacheline_aligned_in_smp; 790 791 struct maple_tree mm_mt; 792 793 unsigned long mmap_base; /* base of mmap area */ 794 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 795 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES 796 /* Base addresses for compatible mmap() */ 797 unsigned long mmap_compat_base; 798 unsigned long mmap_compat_legacy_base; 799 #endif 800 unsigned long task_size; /* size of task vm space */ 801 pgd_t * pgd; 802 803 #ifdef CONFIG_MEMBARRIER 804 /** 805 * @membarrier_state: Flags controlling membarrier behavior. 806 * 807 * This field is close to @pgd to hopefully fit in the same 808 * cache-line, which needs to be touched by switch_mm(). 809 */ 810 atomic_t membarrier_state; 811 #endif 812 813 /** 814 * @mm_users: The number of users including userspace. 815 * 816 * Use mmget()/mmget_not_zero()/mmput() to modify. When this 817 * drops to 0 (i.e. when the task exits and there are no other 818 * temporary reference holders), we also release a reference on 819 * @mm_count (which may then free the &struct mm_struct if 820 * @mm_count also drops to 0). 821 */ 822 atomic_t mm_users; 823 824 #ifdef CONFIG_SCHED_MM_CID 825 /** 826 * @pcpu_cid: Per-cpu current cid. 827 * 828 * Keep track of the currently allocated mm_cid for each cpu. 829 * The per-cpu mm_cid values are serialized by their respective 830 * runqueue locks. 831 */ 832 struct mm_cid __percpu *pcpu_cid; 833 /* 834 * @mm_cid_next_scan: Next mm_cid scan (in jiffies). 835 * 836 * When the next mm_cid scan is due (in jiffies). 837 */ 838 unsigned long mm_cid_next_scan; 839 #endif 840 #ifdef CONFIG_MMU 841 atomic_long_t pgtables_bytes; /* size of all page tables */ 842 #endif 843 int map_count; /* number of VMAs */ 844 845 spinlock_t page_table_lock; /* Protects page tables and some 846 * counters 847 */ 848 /* 849 * With some kernel config, the current mmap_lock's offset 850 * inside 'mm_struct' is at 0x120, which is very optimal, as 851 * its two hot fields 'count' and 'owner' sit in 2 different 852 * cachelines, and when mmap_lock is highly contended, both 853 * of the 2 fields will be accessed frequently, current layout 854 * will help to reduce cache bouncing. 855 * 856 * So please be careful with adding new fields before 857 * mmap_lock, which can easily push the 2 fields into one 858 * cacheline. 859 */ 860 struct rw_semaphore mmap_lock; 861 862 struct list_head mmlist; /* List of maybe swapped mm's. These 863 * are globally strung together off 864 * init_mm.mmlist, and are protected 865 * by mmlist_lock 866 */ 867 #ifdef CONFIG_PER_VMA_LOCK 868 /* 869 * This field has lock-like semantics, meaning it is sometimes 870 * accessed with ACQUIRE/RELEASE semantics. 871 * Roughly speaking, incrementing the sequence number is 872 * equivalent to releasing locks on VMAs; reading the sequence 873 * number can be part of taking a read lock on a VMA. 874 * 875 * Can be modified under write mmap_lock using RELEASE 876 * semantics. 877 * Can be read with no other protection when holding write 878 * mmap_lock. 879 * Can be read with ACQUIRE semantics if not holding write 880 * mmap_lock. 881 */ 882 int mm_lock_seq; 883 #endif 884 885 886 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 887 unsigned long hiwater_vm; /* High-water virtual memory usage */ 888 889 unsigned long total_vm; /* Total pages mapped */ 890 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 891 atomic64_t pinned_vm; /* Refcount permanently increased */ 892 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 893 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 894 unsigned long stack_vm; /* VM_STACK */ 895 unsigned long def_flags; 896 897 /** 898 * @write_protect_seq: Locked when any thread is write 899 * protecting pages mapped by this mm to enforce a later COW, 900 * for instance during page table copying for fork(). 901 */ 902 seqcount_t write_protect_seq; 903 904 spinlock_t arg_lock; /* protect the below fields */ 905 906 unsigned long start_code, end_code, start_data, end_data; 907 unsigned long start_brk, brk, start_stack; 908 unsigned long arg_start, arg_end, env_start, env_end; 909 910 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 911 912 struct percpu_counter rss_stat[NR_MM_COUNTERS]; 913 914 struct linux_binfmt *binfmt; 915 916 /* Architecture-specific MM context */ 917 mm_context_t context; 918 919 unsigned long flags; /* Must use atomic bitops to access */ 920 921 #ifdef CONFIG_AIO 922 spinlock_t ioctx_lock; 923 struct kioctx_table __rcu *ioctx_table; 924 #endif 925 #ifdef CONFIG_MEMCG 926 /* 927 * "owner" points to a task that is regarded as the canonical 928 * user/owner of this mm. All of the following must be true in 929 * order for it to be changed: 930 * 931 * current == mm->owner 932 * current->mm != mm 933 * new_owner->mm == mm 934 * new_owner->alloc_lock is held 935 */ 936 struct task_struct __rcu *owner; 937 #endif 938 struct user_namespace *user_ns; 939 940 /* store ref to file /proc/<pid>/exe symlink points to */ 941 struct file __rcu *exe_file; 942 #ifdef CONFIG_MMU_NOTIFIER 943 struct mmu_notifier_subscriptions *notifier_subscriptions; 944 #endif 945 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 946 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 947 #endif 948 #ifdef CONFIG_NUMA_BALANCING 949 /* 950 * numa_next_scan is the next time that PTEs will be remapped 951 * PROT_NONE to trigger NUMA hinting faults; such faults gather 952 * statistics and migrate pages to new nodes if necessary. 953 */ 954 unsigned long numa_next_scan; 955 956 /* Restart point for scanning and remapping PTEs. */ 957 unsigned long numa_scan_offset; 958 959 /* numa_scan_seq prevents two threads remapping PTEs. */ 960 int numa_scan_seq; 961 #endif 962 /* 963 * An operation with batched TLB flushing is going on. Anything 964 * that can move process memory needs to flush the TLB when 965 * moving a PROT_NONE mapped page. 966 */ 967 atomic_t tlb_flush_pending; 968 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 969 /* See flush_tlb_batched_pending() */ 970 atomic_t tlb_flush_batched; 971 #endif 972 struct uprobes_state uprobes_state; 973 #ifdef CONFIG_PREEMPT_RT 974 struct rcu_head delayed_drop; 975 #endif 976 #ifdef CONFIG_HUGETLB_PAGE 977 atomic_long_t hugetlb_usage; 978 #endif 979 struct work_struct async_put_work; 980 981 #ifdef CONFIG_IOMMU_MM_DATA 982 struct iommu_mm_data *iommu_mm; 983 #endif 984 #ifdef CONFIG_KSM 985 /* 986 * Represent how many pages of this process are involved in KSM 987 * merging (not including ksm_zero_pages). 988 */ 989 unsigned long ksm_merging_pages; 990 /* 991 * Represent how many pages are checked for ksm merging 992 * including merged and not merged. 993 */ 994 unsigned long ksm_rmap_items; 995 /* 996 * Represent how many empty pages are merged with kernel zero 997 * pages when enabling KSM use_zero_pages. 998 */ 999 atomic_long_t ksm_zero_pages; 1000 #endif /* CONFIG_KSM */ 1001 #ifdef CONFIG_LRU_GEN_WALKS_MMU 1002 struct { 1003 /* this mm_struct is on lru_gen_mm_list */ 1004 struct list_head list; 1005 /* 1006 * Set when switching to this mm_struct, as a hint of 1007 * whether it has been used since the last time per-node 1008 * page table walkers cleared the corresponding bits. 1009 */ 1010 unsigned long bitmap; 1011 #ifdef CONFIG_MEMCG 1012 /* points to the memcg of "owner" above */ 1013 struct mem_cgroup *memcg; 1014 #endif 1015 } lru_gen; 1016 #endif /* CONFIG_LRU_GEN_WALKS_MMU */ 1017 } __randomize_layout; 1018 1019 /* 1020 * The mm_cpumask needs to be at the end of mm_struct, because it 1021 * is dynamically sized based on nr_cpu_ids. 1022 */ 1023 unsigned long cpu_bitmap[]; 1024 }; 1025 1026 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \ 1027 MT_FLAGS_USE_RCU) 1028 extern struct mm_struct init_mm; 1029 1030 /* Pointer magic because the dynamic array size confuses some compilers. */ 1031 static inline void mm_init_cpumask(struct mm_struct *mm) 1032 { 1033 unsigned long cpu_bitmap = (unsigned long)mm; 1034 1035 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap); 1036 cpumask_clear((struct cpumask *)cpu_bitmap); 1037 } 1038 1039 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 1040 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 1041 { 1042 return (struct cpumask *)&mm->cpu_bitmap; 1043 } 1044 1045 #ifdef CONFIG_LRU_GEN 1046 1047 struct lru_gen_mm_list { 1048 /* mm_struct list for page table walkers */ 1049 struct list_head fifo; 1050 /* protects the list above */ 1051 spinlock_t lock; 1052 }; 1053 1054 #endif /* CONFIG_LRU_GEN */ 1055 1056 #ifdef CONFIG_LRU_GEN_WALKS_MMU 1057 1058 void lru_gen_add_mm(struct mm_struct *mm); 1059 void lru_gen_del_mm(struct mm_struct *mm); 1060 void lru_gen_migrate_mm(struct mm_struct *mm); 1061 1062 static inline void lru_gen_init_mm(struct mm_struct *mm) 1063 { 1064 INIT_LIST_HEAD(&mm->lru_gen.list); 1065 mm->lru_gen.bitmap = 0; 1066 #ifdef CONFIG_MEMCG 1067 mm->lru_gen.memcg = NULL; 1068 #endif 1069 } 1070 1071 static inline void lru_gen_use_mm(struct mm_struct *mm) 1072 { 1073 /* 1074 * When the bitmap is set, page reclaim knows this mm_struct has been 1075 * used since the last time it cleared the bitmap. So it might be worth 1076 * walking the page tables of this mm_struct to clear the accessed bit. 1077 */ 1078 WRITE_ONCE(mm->lru_gen.bitmap, -1); 1079 } 1080 1081 #else /* !CONFIG_LRU_GEN_WALKS_MMU */ 1082 1083 static inline void lru_gen_add_mm(struct mm_struct *mm) 1084 { 1085 } 1086 1087 static inline void lru_gen_del_mm(struct mm_struct *mm) 1088 { 1089 } 1090 1091 static inline void lru_gen_migrate_mm(struct mm_struct *mm) 1092 { 1093 } 1094 1095 static inline void lru_gen_init_mm(struct mm_struct *mm) 1096 { 1097 } 1098 1099 static inline void lru_gen_use_mm(struct mm_struct *mm) 1100 { 1101 } 1102 1103 #endif /* CONFIG_LRU_GEN_WALKS_MMU */ 1104 1105 struct vma_iterator { 1106 struct ma_state mas; 1107 }; 1108 1109 #define VMA_ITERATOR(name, __mm, __addr) \ 1110 struct vma_iterator name = { \ 1111 .mas = { \ 1112 .tree = &(__mm)->mm_mt, \ 1113 .index = __addr, \ 1114 .node = NULL, \ 1115 .status = ma_start, \ 1116 }, \ 1117 } 1118 1119 static inline void vma_iter_init(struct vma_iterator *vmi, 1120 struct mm_struct *mm, unsigned long addr) 1121 { 1122 mas_init(&vmi->mas, &mm->mm_mt, addr); 1123 } 1124 1125 #ifdef CONFIG_SCHED_MM_CID 1126 1127 enum mm_cid_state { 1128 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */ 1129 MM_CID_LAZY_PUT = (1U << 31), 1130 }; 1131 1132 static inline bool mm_cid_is_unset(int cid) 1133 { 1134 return cid == MM_CID_UNSET; 1135 } 1136 1137 static inline bool mm_cid_is_lazy_put(int cid) 1138 { 1139 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT); 1140 } 1141 1142 static inline bool mm_cid_is_valid(int cid) 1143 { 1144 return !(cid & MM_CID_LAZY_PUT); 1145 } 1146 1147 static inline int mm_cid_set_lazy_put(int cid) 1148 { 1149 return cid | MM_CID_LAZY_PUT; 1150 } 1151 1152 static inline int mm_cid_clear_lazy_put(int cid) 1153 { 1154 return cid & ~MM_CID_LAZY_PUT; 1155 } 1156 1157 /* Accessor for struct mm_struct's cidmask. */ 1158 static inline cpumask_t *mm_cidmask(struct mm_struct *mm) 1159 { 1160 unsigned long cid_bitmap = (unsigned long)mm; 1161 1162 cid_bitmap += offsetof(struct mm_struct, cpu_bitmap); 1163 /* Skip cpu_bitmap */ 1164 cid_bitmap += cpumask_size(); 1165 return (struct cpumask *)cid_bitmap; 1166 } 1167 1168 static inline void mm_init_cid(struct mm_struct *mm) 1169 { 1170 int i; 1171 1172 for_each_possible_cpu(i) { 1173 struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i); 1174 1175 pcpu_cid->cid = MM_CID_UNSET; 1176 pcpu_cid->time = 0; 1177 } 1178 cpumask_clear(mm_cidmask(mm)); 1179 } 1180 1181 static inline int mm_alloc_cid_noprof(struct mm_struct *mm) 1182 { 1183 mm->pcpu_cid = alloc_percpu_noprof(struct mm_cid); 1184 if (!mm->pcpu_cid) 1185 return -ENOMEM; 1186 mm_init_cid(mm); 1187 return 0; 1188 } 1189 #define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__)) 1190 1191 static inline void mm_destroy_cid(struct mm_struct *mm) 1192 { 1193 free_percpu(mm->pcpu_cid); 1194 mm->pcpu_cid = NULL; 1195 } 1196 1197 static inline unsigned int mm_cid_size(void) 1198 { 1199 return cpumask_size(); 1200 } 1201 #else /* CONFIG_SCHED_MM_CID */ 1202 static inline void mm_init_cid(struct mm_struct *mm) { } 1203 static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; } 1204 static inline void mm_destroy_cid(struct mm_struct *mm) { } 1205 static inline unsigned int mm_cid_size(void) 1206 { 1207 return 0; 1208 } 1209 #endif /* CONFIG_SCHED_MM_CID */ 1210 1211 struct mmu_gather; 1212 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); 1213 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); 1214 extern void tlb_finish_mmu(struct mmu_gather *tlb); 1215 1216 struct vm_fault; 1217 1218 /** 1219 * typedef vm_fault_t - Return type for page fault handlers. 1220 * 1221 * Page fault handlers return a bitmask of %VM_FAULT values. 1222 */ 1223 typedef __bitwise unsigned int vm_fault_t; 1224 1225 /** 1226 * enum vm_fault_reason - Page fault handlers return a bitmask of 1227 * these values to tell the core VM what happened when handling the 1228 * fault. Used to decide whether a process gets delivered SIGBUS or 1229 * just gets major/minor fault counters bumped up. 1230 * 1231 * @VM_FAULT_OOM: Out Of Memory 1232 * @VM_FAULT_SIGBUS: Bad access 1233 * @VM_FAULT_MAJOR: Page read from storage 1234 * @VM_FAULT_HWPOISON: Hit poisoned small page 1235 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded 1236 * in upper bits 1237 * @VM_FAULT_SIGSEGV: segmentation fault 1238 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page 1239 * @VM_FAULT_LOCKED: ->fault locked the returned page 1240 * @VM_FAULT_RETRY: ->fault blocked, must retry 1241 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small 1242 * @VM_FAULT_DONE_COW: ->fault has fully handled COW 1243 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs 1244 * fsync() to complete (for synchronous page faults 1245 * in DAX) 1246 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released 1247 * @VM_FAULT_HINDEX_MASK: mask HINDEX value 1248 * 1249 */ 1250 enum vm_fault_reason { 1251 VM_FAULT_OOM = (__force vm_fault_t)0x000001, 1252 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, 1253 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, 1254 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, 1255 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, 1256 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, 1257 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, 1258 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, 1259 VM_FAULT_RETRY = (__force vm_fault_t)0x000400, 1260 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, 1261 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, 1262 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, 1263 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000, 1264 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, 1265 }; 1266 1267 /* Encode hstate index for a hwpoisoned large page */ 1268 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) 1269 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf) 1270 1271 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ 1272 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ 1273 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) 1274 1275 #define VM_FAULT_RESULT_TRACE \ 1276 { VM_FAULT_OOM, "OOM" }, \ 1277 { VM_FAULT_SIGBUS, "SIGBUS" }, \ 1278 { VM_FAULT_MAJOR, "MAJOR" }, \ 1279 { VM_FAULT_HWPOISON, "HWPOISON" }, \ 1280 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ 1281 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ 1282 { VM_FAULT_NOPAGE, "NOPAGE" }, \ 1283 { VM_FAULT_LOCKED, "LOCKED" }, \ 1284 { VM_FAULT_RETRY, "RETRY" }, \ 1285 { VM_FAULT_FALLBACK, "FALLBACK" }, \ 1286 { VM_FAULT_DONE_COW, "DONE_COW" }, \ 1287 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \ 1288 { VM_FAULT_COMPLETED, "COMPLETED" } 1289 1290 struct vm_special_mapping { 1291 const char *name; /* The name, e.g. "[vdso]". */ 1292 1293 /* 1294 * If .fault is not provided, this points to a 1295 * NULL-terminated array of pages that back the special mapping. 1296 * 1297 * This must not be NULL unless .fault is provided. 1298 */ 1299 struct page **pages; 1300 1301 /* 1302 * If non-NULL, then this is called to resolve page faults 1303 * on the special mapping. If used, .pages is not checked. 1304 */ 1305 vm_fault_t (*fault)(const struct vm_special_mapping *sm, 1306 struct vm_area_struct *vma, 1307 struct vm_fault *vmf); 1308 1309 int (*mremap)(const struct vm_special_mapping *sm, 1310 struct vm_area_struct *new_vma); 1311 }; 1312 1313 enum tlb_flush_reason { 1314 TLB_FLUSH_ON_TASK_SWITCH, 1315 TLB_REMOTE_SHOOTDOWN, 1316 TLB_LOCAL_SHOOTDOWN, 1317 TLB_LOCAL_MM_SHOOTDOWN, 1318 TLB_REMOTE_SEND_IPI, 1319 NR_TLB_FLUSH_REASONS, 1320 }; 1321 1322 /** 1323 * enum fault_flag - Fault flag definitions. 1324 * @FAULT_FLAG_WRITE: Fault was a write fault. 1325 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE. 1326 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked. 1327 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying. 1328 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region. 1329 * @FAULT_FLAG_TRIED: The fault has been tried once. 1330 * @FAULT_FLAG_USER: The fault originated in userspace. 1331 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. 1332 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. 1333 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. 1334 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a 1335 * COW mapping, making sure that an exclusive anon page is 1336 * mapped after the fault. 1337 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached. 1338 * We should only access orig_pte if this flag set. 1339 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock. 1340 * 1341 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify 1342 * whether we would allow page faults to retry by specifying these two 1343 * fault flags correctly. Currently there can be three legal combinations: 1344 * 1345 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and 1346 * this is the first try 1347 * 1348 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and 1349 * we've already tried at least once 1350 * 1351 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry 1352 * 1353 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never 1354 * be used. Note that page faults can be allowed to retry for multiple times, 1355 * in which case we'll have an initial fault with flags (a) then later on 1356 * continuous faults with flags (b). We should always try to detect pending 1357 * signals before a retry to make sure the continuous page faults can still be 1358 * interrupted if necessary. 1359 * 1360 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal. 1361 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when 1362 * applied to mappings that are not COW mappings. 1363 */ 1364 enum fault_flag { 1365 FAULT_FLAG_WRITE = 1 << 0, 1366 FAULT_FLAG_MKWRITE = 1 << 1, 1367 FAULT_FLAG_ALLOW_RETRY = 1 << 2, 1368 FAULT_FLAG_RETRY_NOWAIT = 1 << 3, 1369 FAULT_FLAG_KILLABLE = 1 << 4, 1370 FAULT_FLAG_TRIED = 1 << 5, 1371 FAULT_FLAG_USER = 1 << 6, 1372 FAULT_FLAG_REMOTE = 1 << 7, 1373 FAULT_FLAG_INSTRUCTION = 1 << 8, 1374 FAULT_FLAG_INTERRUPTIBLE = 1 << 9, 1375 FAULT_FLAG_UNSHARE = 1 << 10, 1376 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11, 1377 FAULT_FLAG_VMA_LOCK = 1 << 12, 1378 }; 1379 1380 typedef unsigned int __bitwise zap_flags_t; 1381 1382 /* Flags for clear_young_dirty_ptes(). */ 1383 typedef int __bitwise cydp_t; 1384 1385 /* Clear the access bit */ 1386 #define CYDP_CLEAR_YOUNG ((__force cydp_t)BIT(0)) 1387 1388 /* Clear the dirty bit */ 1389 #define CYDP_CLEAR_DIRTY ((__force cydp_t)BIT(1)) 1390 1391 /* 1392 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each 1393 * other. Here is what they mean, and how to use them: 1394 * 1395 * 1396 * FIXME: For pages which are part of a filesystem, mappings are subject to the 1397 * lifetime enforced by the filesystem and we need guarantees that longterm 1398 * users like RDMA and V4L2 only establish mappings which coordinate usage with 1399 * the filesystem. Ideas for this coordination include revoking the longterm 1400 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was 1401 * added after the problem with filesystems was found FS DAX VMAs are 1402 * specifically failed. Filesystem pages are still subject to bugs and use of 1403 * FOLL_LONGTERM should be avoided on those pages. 1404 * 1405 * In the CMA case: long term pins in a CMA region would unnecessarily fragment 1406 * that region. And so, CMA attempts to migrate the page before pinning, when 1407 * FOLL_LONGTERM is specified. 1408 * 1409 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount, 1410 * but an additional pin counting system) will be invoked. This is intended for 1411 * anything that gets a page reference and then touches page data (for example, 1412 * Direct IO). This lets the filesystem know that some non-file-system entity is 1413 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages 1414 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by 1415 * a call to unpin_user_page(). 1416 * 1417 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different 1418 * and separate refcounting mechanisms, however, and that means that each has 1419 * its own acquire and release mechanisms: 1420 * 1421 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release. 1422 * 1423 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release. 1424 * 1425 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call. 1426 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based 1427 * calls applied to them, and that's perfectly OK. This is a constraint on the 1428 * callers, not on the pages.) 1429 * 1430 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never 1431 * directly by the caller. That's in order to help avoid mismatches when 1432 * releasing pages: get_user_pages*() pages must be released via put_page(), 1433 * while pin_user_pages*() pages must be released via unpin_user_page(). 1434 * 1435 * Please see Documentation/core-api/pin_user_pages.rst for more information. 1436 */ 1437 1438 enum { 1439 /* check pte is writable */ 1440 FOLL_WRITE = 1 << 0, 1441 /* do get_page on page */ 1442 FOLL_GET = 1 << 1, 1443 /* give error on hole if it would be zero */ 1444 FOLL_DUMP = 1 << 2, 1445 /* get_user_pages read/write w/o permission */ 1446 FOLL_FORCE = 1 << 3, 1447 /* 1448 * if a disk transfer is needed, start the IO and return without waiting 1449 * upon it 1450 */ 1451 FOLL_NOWAIT = 1 << 4, 1452 /* do not fault in pages */ 1453 FOLL_NOFAULT = 1 << 5, 1454 /* check page is hwpoisoned */ 1455 FOLL_HWPOISON = 1 << 6, 1456 /* don't do file mappings */ 1457 FOLL_ANON = 1 << 7, 1458 /* 1459 * FOLL_LONGTERM indicates that the page will be held for an indefinite 1460 * time period _often_ under userspace control. This is in contrast to 1461 * iov_iter_get_pages(), whose usages are transient. 1462 */ 1463 FOLL_LONGTERM = 1 << 8, 1464 /* split huge pmd before returning */ 1465 FOLL_SPLIT_PMD = 1 << 9, 1466 /* allow returning PCI P2PDMA pages */ 1467 FOLL_PCI_P2PDMA = 1 << 10, 1468 /* allow interrupts from generic signals */ 1469 FOLL_INTERRUPTIBLE = 1 << 11, 1470 /* 1471 * Always honor (trigger) NUMA hinting faults. 1472 * 1473 * FOLL_WRITE implicitly honors NUMA hinting faults because a 1474 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE 1475 * apply). get_user_pages_fast_only() always implicitly honors NUMA 1476 * hinting faults. 1477 */ 1478 FOLL_HONOR_NUMA_FAULT = 1 << 12, 1479 1480 /* See also internal only FOLL flags in mm/internal.h */ 1481 }; 1482 1483 #endif /* _LINUX_MM_TYPES_H */ 1484