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