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