1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_MM_TYPES_H 3 #define _LINUX_MM_TYPES_H 4 5 #include <linux/mm_types_task.h> 6 7 #include <linux/auxvec.h> 8 #include <linux/kref.h> 9 #include <linux/list.h> 10 #include <linux/spinlock.h> 11 #include <linux/rbtree.h> 12 #include <linux/maple_tree.h> 13 #include <linux/rwsem.h> 14 #include <linux/completion.h> 15 #include <linux/cpumask.h> 16 #include <linux/uprobes.h> 17 #include <linux/rcupdate.h> 18 #include <linux/page-flags-layout.h> 19 #include <linux/workqueue.h> 20 #include <linux/seqlock.h> 21 #include <linux/percpu_counter.h> 22 23 #include <asm/mmu.h> 24 25 #ifndef AT_VECTOR_SIZE_ARCH 26 #define AT_VECTOR_SIZE_ARCH 0 27 #endif 28 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) 29 30 #define INIT_PASID 0 31 32 struct address_space; 33 struct mem_cgroup; 34 35 /* 36 * Each physical page in the system has a struct page associated with 37 * it to keep track of whatever it is we are using the page for at the 38 * moment. Note that we have no way to track which tasks are using 39 * a page, though if it is a pagecache page, rmap structures can tell us 40 * who is mapping it. 41 * 42 * If you allocate the page using alloc_pages(), you can use some of the 43 * space in struct page for your own purposes. The five words in the main 44 * union are available, except for bit 0 of the first word which must be 45 * kept clear. Many users use this word to store a pointer to an object 46 * which is guaranteed to be aligned. If you use the same storage as 47 * page->mapping, you must restore it to NULL before freeing the page. 48 * 49 * The mapcount field must not be used for own purposes. 50 * 51 * If you want to use the refcount field, it must be used in such a way 52 * that other CPUs temporarily incrementing and then decrementing the 53 * refcount does not cause problems. On receiving the page from 54 * alloc_pages(), the refcount will be positive. 55 * 56 * If you allocate pages of order > 0, you can use some of the fields 57 * in each subpage, but you may need to restore some of their values 58 * afterwards. 59 * 60 * SLUB uses cmpxchg_double() to atomically update its freelist and counters. 61 * That requires that freelist & counters in struct slab be adjacent and 62 * double-word aligned. Because struct slab currently just reinterprets the 63 * bits of struct page, we align all struct pages to double-word boundaries, 64 * and ensure that 'freelist' is aligned within struct slab. 65 */ 66 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 67 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) 68 #else 69 #define _struct_page_alignment __aligned(sizeof(unsigned long)) 70 #endif 71 72 struct page { 73 unsigned long flags; /* Atomic flags, some possibly 74 * updated asynchronously */ 75 /* 76 * Five words (20/40 bytes) are available in this union. 77 * WARNING: bit 0 of the first word is used for PageTail(). That 78 * means the other users of this union MUST NOT use the bit to 79 * avoid collision and false-positive PageTail(). 80 */ 81 union { 82 struct { /* Page cache and anonymous pages */ 83 /** 84 * @lru: Pageout list, eg. active_list protected by 85 * lruvec->lru_lock. Sometimes used as a generic list 86 * by the page owner. 87 */ 88 union { 89 struct list_head lru; 90 91 /* Or, for the Unevictable "LRU list" slot */ 92 struct { 93 /* Always even, to negate PageTail */ 94 void *__filler; 95 /* Count page's or folio's mlocks */ 96 unsigned int mlock_count; 97 }; 98 99 /* Or, free page */ 100 struct list_head buddy_list; 101 struct list_head pcp_list; 102 struct { 103 struct llist_node pcp_llist; 104 unsigned int order; 105 }; 106 }; 107 /* See page-flags.h for PAGE_MAPPING_FLAGS */ 108 struct address_space *mapping; 109 union { 110 pgoff_t index; /* Our offset within mapping. */ 111 unsigned long share; /* share count for fsdax */ 112 }; 113 /** 114 * @private: Mapping-private opaque data. 115 * Usually used for buffer_heads if PagePrivate. 116 * Used for swp_entry_t if swapcache flag set. 117 * Indicates order in the buddy system if PageBuddy. 118 */ 119 unsigned long private; 120 }; 121 struct { /* page_pool used by netstack */ 122 /** 123 * @pp_magic: magic value to avoid recycling non 124 * page_pool allocated pages. 125 */ 126 unsigned long pp_magic; 127 struct page_pool *pp; 128 unsigned long _pp_mapping_pad; 129 unsigned long dma_addr; 130 atomic_long_t pp_ref_count; 131 }; 132 struct { /* Tail pages of compound page */ 133 unsigned long compound_head; /* Bit zero is set */ 134 }; 135 struct { /* ZONE_DEVICE pages */ 136 /** @pgmap: Points to the hosting device page map. */ 137 struct dev_pagemap *pgmap; 138 void *zone_device_data; 139 /* 140 * ZONE_DEVICE private pages are counted as being 141 * mapped so the next 3 words hold the mapping, index, 142 * and private fields from the source anonymous or 143 * page cache page while the page is migrated to device 144 * private memory. 145 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also 146 * use the mapping, index, and private fields when 147 * pmem backed DAX files are mapped. 148 */ 149 }; 150 151 /** @rcu_head: You can use this to free a page by RCU. */ 152 struct rcu_head rcu_head; 153 }; 154 155 union { /* This union is 4 bytes in size. */ 156 /* 157 * For head pages of typed folios, the value stored here 158 * allows for determining what this page is used for. The 159 * tail pages of typed folios will not store a type 160 * (page_type == _mapcount == -1). 161 * 162 * See page-flags.h for a list of page types which are currently 163 * stored here. 164 * 165 * Owners of typed folios may reuse the lower 16 bit of the 166 * head page page_type field after setting the page type, 167 * but must reset these 16 bit to -1 before clearing the 168 * page type. 169 */ 170 unsigned int page_type; 171 172 /* 173 * For pages that are part of non-typed folios for which mappings 174 * are tracked via the RMAP, encodes the number of times this page 175 * is directly referenced by a page table. 176 * 177 * Note that the mapcount is always initialized to -1, so that 178 * transitions both from it and to it can be tracked, using 179 * atomic_inc_and_test() and atomic_add_negative(-1). 180 */ 181 atomic_t _mapcount; 182 }; 183 184 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */ 185 atomic_t _refcount; 186 187 #ifdef CONFIG_MEMCG 188 unsigned long memcg_data; 189 #elif defined(CONFIG_SLAB_OBJ_EXT) 190 unsigned long _unused_slab_obj_exts; 191 #endif 192 193 /* 194 * On machines where all RAM is mapped into kernel address space, 195 * we can simply calculate the virtual address. On machines with 196 * highmem some memory is mapped into kernel virtual memory 197 * dynamically, so we need a place to store that address. 198 * Note that this field could be 16 bits on x86 ... ;) 199 * 200 * Architectures with slow multiplication can define 201 * WANT_PAGE_VIRTUAL in asm/page.h 202 */ 203 #if defined(WANT_PAGE_VIRTUAL) 204 void *virtual; /* Kernel virtual address (NULL if 205 not kmapped, ie. highmem) */ 206 #endif /* WANT_PAGE_VIRTUAL */ 207 208 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 209 int _last_cpupid; 210 #endif 211 212 #ifdef CONFIG_KMSAN 213 /* 214 * KMSAN metadata for this page: 215 * - shadow page: every bit indicates whether the corresponding 216 * bit of the original page is initialized (0) or not (1); 217 * - origin page: every 4 bytes contain an id of the stack trace 218 * where the uninitialized value was created. 219 */ 220 struct page *kmsan_shadow; 221 struct page *kmsan_origin; 222 #endif 223 } _struct_page_alignment; 224 225 /* 226 * struct encoded_page - a nonexistent type marking this pointer 227 * 228 * An 'encoded_page' pointer is a pointer to a regular 'struct page', but 229 * with the low bits of the pointer indicating extra context-dependent 230 * information. Only used in mmu_gather handling, and this acts as a type 231 * system check on that use. 232 * 233 * We only really have two guaranteed bits in general, although you could 234 * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 235 * for more. 236 * 237 * Use the supplied helper functions to endcode/decode the pointer and bits. 238 */ 239 struct encoded_page; 240 241 #define ENCODED_PAGE_BITS 3ul 242 243 /* Perform rmap removal after we have flushed the TLB. */ 244 #define ENCODED_PAGE_BIT_DELAY_RMAP 1ul 245 246 /* 247 * The next item in an encoded_page array is the "nr_pages" argument, specifying 248 * the number of consecutive pages starting from this page, that all belong to 249 * the same folio. For example, "nr_pages" corresponds to the number of folio 250 * references that must be dropped. If this bit is not set, "nr_pages" is 251 * implicitly 1. 252 */ 253 #define ENCODED_PAGE_BIT_NR_PAGES_NEXT 2ul 254 255 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags) 256 { 257 BUILD_BUG_ON(flags > ENCODED_PAGE_BITS); 258 return (struct encoded_page *)(flags | (unsigned long)page); 259 } 260 261 static inline unsigned long encoded_page_flags(struct encoded_page *page) 262 { 263 return ENCODED_PAGE_BITS & (unsigned long)page; 264 } 265 266 static inline struct page *encoded_page_ptr(struct encoded_page *page) 267 { 268 return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page); 269 } 270 271 static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr) 272 { 273 VM_WARN_ON_ONCE((nr << 2) >> 2 != nr); 274 return (struct encoded_page *)(nr << 2); 275 } 276 277 static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page) 278 { 279 return ((unsigned long)page) >> 2; 280 } 281 282 /* 283 * A swap entry has to fit into a "unsigned long", as the entry is hidden 284 * in the "index" field of the swapper address space. 285 */ 286 typedef struct { 287 unsigned long val; 288 } swp_entry_t; 289 290 /** 291 * struct folio - Represents a contiguous set of bytes. 292 * @flags: Identical to the page flags. 293 * @lru: Least Recently Used list; tracks how recently this folio was used. 294 * @mlock_count: Number of times this folio has been pinned by mlock(). 295 * @mapping: The file this page belongs to, or refers to the anon_vma for 296 * anonymous memory. 297 * @index: Offset within the file, in units of pages. For anonymous memory, 298 * this is the index from the beginning of the mmap. 299 * @private: Filesystem per-folio data (see folio_attach_private()). 300 * @swap: Used for swp_entry_t if folio_test_swapcache(). 301 * @_mapcount: Do not access this member directly. Use folio_mapcount() to 302 * find out how many times this folio is mapped by userspace. 303 * @_refcount: Do not access this member directly. Use folio_ref_count() 304 * to find how many references there are to this folio. 305 * @memcg_data: Memory Control Group data. 306 * @virtual: Virtual address in the kernel direct map. 307 * @_last_cpupid: IDs of last CPU and last process that accessed the folio. 308 * @_entire_mapcount: Do not use directly, call folio_entire_mapcount(). 309 * @_large_mapcount: Do not use directly, call folio_mapcount(). 310 * @_nr_pages_mapped: Do not use outside of rmap and debug code. 311 * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). 312 * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). 313 * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h. 314 * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h. 315 * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h. 316 * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head(). 317 * @_deferred_list: Folios to be split under memory pressure. 318 * @_unused_slab_obj_exts: Placeholder to match obj_exts in struct slab. 319 * 320 * A folio is a physically, virtually and logically contiguous set 321 * of bytes. It is a power-of-two in size, and it is aligned to that 322 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is 323 * in the page cache, it is at a file offset which is a multiple of that 324 * power-of-two. It may be mapped into userspace at an address which is 325 * at an arbitrary page offset, but its kernel virtual address is aligned 326 * to its size. 327 */ 328 struct folio { 329 /* private: don't document the anon union */ 330 union { 331 struct { 332 /* public: */ 333 unsigned long flags; 334 union { 335 struct list_head lru; 336 /* private: avoid cluttering the output */ 337 struct { 338 void *__filler; 339 /* public: */ 340 unsigned int mlock_count; 341 /* private: */ 342 }; 343 /* public: */ 344 }; 345 struct address_space *mapping; 346 pgoff_t index; 347 union { 348 void *private; 349 swp_entry_t swap; 350 }; 351 atomic_t _mapcount; 352 atomic_t _refcount; 353 #ifdef CONFIG_MEMCG 354 unsigned long memcg_data; 355 #elif defined(CONFIG_SLAB_OBJ_EXT) 356 unsigned long _unused_slab_obj_exts; 357 #endif 358 #if defined(WANT_PAGE_VIRTUAL) 359 void *virtual; 360 #endif 361 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 362 int _last_cpupid; 363 #endif 364 /* private: the union with struct page is transitional */ 365 }; 366 struct page page; 367 }; 368 union { 369 struct { 370 unsigned long _flags_1; 371 unsigned long _head_1; 372 /* public: */ 373 atomic_t _large_mapcount; 374 atomic_t _entire_mapcount; 375 atomic_t _nr_pages_mapped; 376 atomic_t _pincount; 377 #ifdef CONFIG_64BIT 378 unsigned int _folio_nr_pages; 379 #endif 380 /* private: the union with struct page is transitional */ 381 }; 382 struct page __page_1; 383 }; 384 union { 385 struct { 386 unsigned long _flags_2; 387 unsigned long _head_2; 388 /* public: */ 389 void *_hugetlb_subpool; 390 void *_hugetlb_cgroup; 391 void *_hugetlb_cgroup_rsvd; 392 void *_hugetlb_hwpoison; 393 /* private: the union with struct page is transitional */ 394 }; 395 struct { 396 unsigned long _flags_2a; 397 unsigned long _head_2a; 398 /* public: */ 399 struct list_head _deferred_list; 400 /* private: the union with struct page is transitional */ 401 }; 402 struct page __page_2; 403 }; 404 }; 405 406 #define FOLIO_MATCH(pg, fl) \ 407 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl)) 408 FOLIO_MATCH(flags, flags); 409 FOLIO_MATCH(lru, lru); 410 FOLIO_MATCH(mapping, mapping); 411 FOLIO_MATCH(compound_head, lru); 412 FOLIO_MATCH(index, index); 413 FOLIO_MATCH(private, private); 414 FOLIO_MATCH(_mapcount, _mapcount); 415 FOLIO_MATCH(_refcount, _refcount); 416 #ifdef CONFIG_MEMCG 417 FOLIO_MATCH(memcg_data, memcg_data); 418 #endif 419 #if defined(WANT_PAGE_VIRTUAL) 420 FOLIO_MATCH(virtual, virtual); 421 #endif 422 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 423 FOLIO_MATCH(_last_cpupid, _last_cpupid); 424 #endif 425 #undef FOLIO_MATCH 426 #define FOLIO_MATCH(pg, fl) \ 427 static_assert(offsetof(struct folio, fl) == \ 428 offsetof(struct page, pg) + sizeof(struct page)) 429 FOLIO_MATCH(flags, _flags_1); 430 FOLIO_MATCH(compound_head, _head_1); 431 #undef FOLIO_MATCH 432 #define FOLIO_MATCH(pg, fl) \ 433 static_assert(offsetof(struct folio, fl) == \ 434 offsetof(struct page, pg) + 2 * sizeof(struct page)) 435 FOLIO_MATCH(flags, _flags_2); 436 FOLIO_MATCH(compound_head, _head_2); 437 FOLIO_MATCH(flags, _flags_2a); 438 FOLIO_MATCH(compound_head, _head_2a); 439 #undef FOLIO_MATCH 440 441 /** 442 * struct ptdesc - Memory descriptor for page tables. 443 * @__page_flags: Same as page flags. Powerpc only. 444 * @pt_rcu_head: For freeing page table pages. 445 * @pt_list: List of used page tables. Used for s390 gmap shadow pages 446 * (which are not linked into the user page tables) and x86 447 * pgds. 448 * @_pt_pad_1: Padding that aliases with page's compound head. 449 * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs. 450 * @__page_mapping: Aliases with page->mapping. Unused for page tables. 451 * @pt_index: Used for s390 gmap. 452 * @pt_mm: Used for x86 pgds. 453 * @pt_frag_refcount: For fragmented page table tracking. Powerpc only. 454 * @pt_share_count: Used for HugeTLB PMD page table share count. 455 * @_pt_pad_2: Padding to ensure proper alignment. 456 * @ptl: Lock for the page table. 457 * @__page_type: Same as page->page_type. Unused for page tables. 458 * @__page_refcount: Same as page refcount. 459 * @pt_memcg_data: Memcg data. Tracked for page tables here. 460 * 461 * This struct overlays struct page for now. Do not modify without a good 462 * understanding of the issues. 463 */ 464 struct ptdesc { 465 unsigned long __page_flags; 466 467 union { 468 struct rcu_head pt_rcu_head; 469 struct list_head pt_list; 470 struct { 471 unsigned long _pt_pad_1; 472 pgtable_t pmd_huge_pte; 473 }; 474 }; 475 unsigned long __page_mapping; 476 477 union { 478 pgoff_t pt_index; 479 struct mm_struct *pt_mm; 480 atomic_t pt_frag_refcount; 481 #ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING 482 atomic_t pt_share_count; 483 #endif 484 }; 485 486 union { 487 unsigned long _pt_pad_2; 488 #if ALLOC_SPLIT_PTLOCKS 489 spinlock_t *ptl; 490 #else 491 spinlock_t ptl; 492 #endif 493 }; 494 unsigned int __page_type; 495 atomic_t __page_refcount; 496 #ifdef CONFIG_MEMCG 497 unsigned long pt_memcg_data; 498 #endif 499 }; 500 501 #define TABLE_MATCH(pg, pt) \ 502 static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt)) 503 TABLE_MATCH(flags, __page_flags); 504 TABLE_MATCH(compound_head, pt_list); 505 TABLE_MATCH(compound_head, _pt_pad_1); 506 TABLE_MATCH(mapping, __page_mapping); 507 TABLE_MATCH(index, pt_index); 508 TABLE_MATCH(rcu_head, pt_rcu_head); 509 TABLE_MATCH(page_type, __page_type); 510 TABLE_MATCH(_refcount, __page_refcount); 511 #ifdef CONFIG_MEMCG 512 TABLE_MATCH(memcg_data, pt_memcg_data); 513 #endif 514 #undef TABLE_MATCH 515 static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); 516 517 #define ptdesc_page(pt) (_Generic((pt), \ 518 const struct ptdesc *: (const struct page *)(pt), \ 519 struct ptdesc *: (struct page *)(pt))) 520 521 #define ptdesc_folio(pt) (_Generic((pt), \ 522 const struct ptdesc *: (const struct folio *)(pt), \ 523 struct ptdesc *: (struct folio *)(pt))) 524 525 #define page_ptdesc(p) (_Generic((p), \ 526 const struct page *: (const struct ptdesc *)(p), \ 527 struct page *: (struct ptdesc *)(p))) 528 529 #ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING 530 static inline void ptdesc_pmd_pts_init(struct ptdesc *ptdesc) 531 { 532 atomic_set(&ptdesc->pt_share_count, 0); 533 } 534 535 static inline void ptdesc_pmd_pts_inc(struct ptdesc *ptdesc) 536 { 537 atomic_inc(&ptdesc->pt_share_count); 538 } 539 540 static inline void ptdesc_pmd_pts_dec(struct ptdesc *ptdesc) 541 { 542 atomic_dec(&ptdesc->pt_share_count); 543 } 544 545 static inline int ptdesc_pmd_pts_count(struct ptdesc *ptdesc) 546 { 547 return atomic_read(&ptdesc->pt_share_count); 548 } 549 #else 550 static inline void ptdesc_pmd_pts_init(struct ptdesc *ptdesc) 551 { 552 } 553 #endif 554 555 /* 556 * Used for sizing the vmemmap region on some architectures 557 */ 558 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) 559 560 /* 561 * page_private can be used on tail pages. However, PagePrivate is only 562 * checked by the VM on the head page. So page_private on the tail pages 563 * should be used for data that's ancillary to the head page (eg attaching 564 * buffer heads to tail pages after attaching buffer heads to the head page) 565 */ 566 #define page_private(page) ((page)->private) 567 568 static inline void set_page_private(struct page *page, unsigned long private) 569 { 570 page->private = private; 571 } 572 573 static inline void *folio_get_private(struct folio *folio) 574 { 575 return folio->private; 576 } 577 578 typedef unsigned long vm_flags_t; 579 580 /* 581 * A region containing a mapping of a non-memory backed file under NOMMU 582 * conditions. These are held in a global tree and are pinned by the VMAs that 583 * map parts of them. 584 */ 585 struct vm_region { 586 struct rb_node vm_rb; /* link in global region tree */ 587 vm_flags_t vm_flags; /* VMA vm_flags */ 588 unsigned long vm_start; /* start address of region */ 589 unsigned long vm_end; /* region initialised to here */ 590 unsigned long vm_top; /* region allocated to here */ 591 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 592 struct file *vm_file; /* the backing file or NULL */ 593 594 int vm_usage; /* region usage count (access under nommu_region_sem) */ 595 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 596 * this region */ 597 }; 598 599 #ifdef CONFIG_USERFAULTFD 600 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 601 struct vm_userfaultfd_ctx { 602 struct userfaultfd_ctx *ctx; 603 }; 604 #else /* CONFIG_USERFAULTFD */ 605 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 606 struct vm_userfaultfd_ctx {}; 607 #endif /* CONFIG_USERFAULTFD */ 608 609 struct anon_vma_name { 610 struct kref kref; 611 /* The name needs to be at the end because it is dynamically sized. */ 612 char name[]; 613 }; 614 615 #ifdef CONFIG_ANON_VMA_NAME 616 /* 617 * mmap_lock should be read-locked when calling anon_vma_name(). Caller should 618 * either keep holding the lock while using the returned pointer or it should 619 * raise anon_vma_name refcount before releasing the lock. 620 */ 621 struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); 622 struct anon_vma_name *anon_vma_name_alloc(const char *name); 623 void anon_vma_name_free(struct kref *kref); 624 #else /* CONFIG_ANON_VMA_NAME */ 625 static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) 626 { 627 return NULL; 628 } 629 630 static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) 631 { 632 return NULL; 633 } 634 #endif 635 636 struct vma_lock { 637 struct rw_semaphore lock; 638 }; 639 640 struct vma_numab_state { 641 /* 642 * Initialised as time in 'jiffies' after which VMA 643 * should be scanned. Delays first scan of new VMA by at 644 * least sysctl_numa_balancing_scan_delay: 645 */ 646 unsigned long next_scan; 647 648 /* 649 * Time in jiffies when pids_active[] is reset to 650 * detect phase change behaviour: 651 */ 652 unsigned long pids_active_reset; 653 654 /* 655 * Approximate tracking of PIDs that trapped a NUMA hinting 656 * fault. May produce false positives due to hash collisions. 657 * 658 * [0] Previous PID tracking 659 * [1] Current PID tracking 660 * 661 * Window moves after next_pid_reset has expired approximately 662 * every VMA_PID_RESET_PERIOD jiffies: 663 */ 664 unsigned long pids_active[2]; 665 666 /* MM scan sequence ID when scan first started after VMA creation */ 667 int start_scan_seq; 668 669 /* 670 * MM scan sequence ID when the VMA was last completely scanned. 671 * A VMA is not eligible for scanning if prev_scan_seq == numa_scan_seq 672 */ 673 int prev_scan_seq; 674 }; 675 676 /* 677 * This struct describes a virtual memory area. There is one of these 678 * per VM-area/task. A VM area is any part of the process virtual memory 679 * space that has a special rule for the page-fault handlers (ie a shared 680 * library, the executable area etc). 681 * 682 * Only explicitly marked struct members may be accessed by RCU readers before 683 * getting a stable reference. 684 */ 685 struct vm_area_struct { 686 /* The first cache line has the info for VMA tree walking. */ 687 688 union { 689 struct { 690 /* VMA covers [vm_start; vm_end) addresses within mm */ 691 unsigned long vm_start; 692 unsigned long vm_end; 693 }; 694 #ifdef CONFIG_PER_VMA_LOCK 695 struct rcu_head vm_rcu; /* Used for deferred freeing. */ 696 #endif 697 }; 698 699 /* 700 * The address space we belong to. 701 * Unstable RCU readers are allowed to read this. 702 */ 703 struct mm_struct *vm_mm; 704 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 705 706 /* 707 * Flags, see mm.h. 708 * To modify use vm_flags_{init|reset|set|clear|mod} functions. 709 */ 710 union { 711 const vm_flags_t vm_flags; 712 vm_flags_t __private __vm_flags; 713 }; 714 715 #ifdef CONFIG_PER_VMA_LOCK 716 /* 717 * Flag to indicate areas detached from the mm->mm_mt tree. 718 * Unstable RCU readers are allowed to read this. 719 */ 720 bool detached; 721 722 /* 723 * Can only be written (using WRITE_ONCE()) while holding both: 724 * - mmap_lock (in write mode) 725 * - vm_lock->lock (in write mode) 726 * Can be read reliably while holding one of: 727 * - mmap_lock (in read or write mode) 728 * - vm_lock->lock (in read or write mode) 729 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout 730 * while holding nothing (except RCU to keep the VMA struct allocated). 731 * 732 * This sequence counter is explicitly allowed to overflow; sequence 733 * counter reuse can only lead to occasional unnecessary use of the 734 * slowpath. 735 */ 736 unsigned int vm_lock_seq; 737 /* Unstable RCU readers are allowed to read this. */ 738 struct vma_lock *vm_lock; 739 #endif 740 741 /* 742 * For areas with an address space and backing store, 743 * linkage into the address_space->i_mmap interval tree. 744 * 745 */ 746 struct { 747 struct rb_node rb; 748 unsigned long rb_subtree_last; 749 } shared; 750 751 /* 752 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 753 * list, after a COW of one of the file pages. A MAP_SHARED vma 754 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 755 * or brk vma (with NULL file) can only be in an anon_vma list. 756 */ 757 struct list_head anon_vma_chain; /* Serialized by mmap_lock & 758 * page_table_lock */ 759 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 760 761 /* Function pointers to deal with this struct. */ 762 const struct vm_operations_struct *vm_ops; 763 764 /* Information about our backing store: */ 765 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 766 units */ 767 struct file * vm_file; /* File we map to (can be NULL). */ 768 void * vm_private_data; /* was vm_pte (shared mem) */ 769 770 #ifdef CONFIG_ANON_VMA_NAME 771 /* 772 * For private and shared anonymous mappings, a pointer to a null 773 * terminated string containing the name given to the vma, or NULL if 774 * unnamed. Serialized by mmap_lock. Use anon_vma_name to access. 775 */ 776 struct anon_vma_name *anon_name; 777 #endif 778 #ifdef CONFIG_SWAP 779 atomic_long_t swap_readahead_info; 780 #endif 781 #ifndef CONFIG_MMU 782 struct vm_region *vm_region; /* NOMMU mapping region */ 783 #endif 784 #ifdef CONFIG_NUMA 785 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 786 #endif 787 #ifdef CONFIG_NUMA_BALANCING 788 struct vma_numab_state *numab_state; /* NUMA Balancing state */ 789 #endif 790 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 791 } __randomize_layout; 792 793 #ifdef CONFIG_NUMA 794 #define vma_policy(vma) ((vma)->vm_policy) 795 #else 796 #define vma_policy(vma) NULL 797 #endif 798 799 #ifdef CONFIG_SCHED_MM_CID 800 struct mm_cid { 801 u64 time; 802 int cid; 803 int recent_cid; 804 }; 805 #endif 806 807 struct kioctx_table; 808 struct iommu_mm_data; 809 struct mm_struct { 810 struct { 811 /* 812 * Fields which are often written to are placed in a separate 813 * cache line. 814 */ 815 struct { 816 /** 817 * @mm_count: The number of references to &struct 818 * mm_struct (@mm_users count as 1). 819 * 820 * Use mmgrab()/mmdrop() to modify. When this drops to 821 * 0, the &struct mm_struct is freed. 822 */ 823 atomic_t mm_count; 824 } ____cacheline_aligned_in_smp; 825 826 struct maple_tree mm_mt; 827 828 unsigned long mmap_base; /* base of mmap area */ 829 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 830 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES 831 /* Base addresses for compatible mmap() */ 832 unsigned long mmap_compat_base; 833 unsigned long mmap_compat_legacy_base; 834 #endif 835 unsigned long task_size; /* size of task vm space */ 836 pgd_t * pgd; 837 838 #ifdef CONFIG_MEMBARRIER 839 /** 840 * @membarrier_state: Flags controlling membarrier behavior. 841 * 842 * This field is close to @pgd to hopefully fit in the same 843 * cache-line, which needs to be touched by switch_mm(). 844 */ 845 atomic_t membarrier_state; 846 #endif 847 848 /** 849 * @mm_users: The number of users including userspace. 850 * 851 * Use mmget()/mmget_not_zero()/mmput() to modify. When this 852 * drops to 0 (i.e. when the task exits and there are no other 853 * temporary reference holders), we also release a reference on 854 * @mm_count (which may then free the &struct mm_struct if 855 * @mm_count also drops to 0). 856 */ 857 atomic_t mm_users; 858 859 #ifdef CONFIG_SCHED_MM_CID 860 /** 861 * @pcpu_cid: Per-cpu current cid. 862 * 863 * Keep track of the currently allocated mm_cid for each cpu. 864 * The per-cpu mm_cid values are serialized by their respective 865 * runqueue locks. 866 */ 867 struct mm_cid __percpu *pcpu_cid; 868 /* 869 * @mm_cid_next_scan: Next mm_cid scan (in jiffies). 870 * 871 * When the next mm_cid scan is due (in jiffies). 872 */ 873 unsigned long mm_cid_next_scan; 874 /** 875 * @nr_cpus_allowed: Number of CPUs allowed for mm. 876 * 877 * Number of CPUs allowed in the union of all mm's 878 * threads allowed CPUs. 879 */ 880 unsigned int nr_cpus_allowed; 881 /** 882 * @max_nr_cid: Maximum number of allowed concurrency 883 * IDs allocated. 884 * 885 * Track the highest number of allowed concurrency IDs 886 * allocated for the mm. 887 */ 888 atomic_t max_nr_cid; 889 /** 890 * @cpus_allowed_lock: Lock protecting mm cpus_allowed. 891 * 892 * Provide mutual exclusion for mm cpus_allowed and 893 * mm nr_cpus_allowed updates. 894 */ 895 raw_spinlock_t cpus_allowed_lock; 896 #endif 897 #ifdef CONFIG_MMU 898 atomic_long_t pgtables_bytes; /* size of all page tables */ 899 #endif 900 int map_count; /* number of VMAs */ 901 902 spinlock_t page_table_lock; /* Protects page tables and some 903 * counters 904 */ 905 /* 906 * With some kernel config, the current mmap_lock's offset 907 * inside 'mm_struct' is at 0x120, which is very optimal, as 908 * its two hot fields 'count' and 'owner' sit in 2 different 909 * cachelines, and when mmap_lock is highly contended, both 910 * of the 2 fields will be accessed frequently, current layout 911 * will help to reduce cache bouncing. 912 * 913 * So please be careful with adding new fields before 914 * mmap_lock, which can easily push the 2 fields into one 915 * cacheline. 916 */ 917 struct rw_semaphore mmap_lock; 918 919 struct list_head mmlist; /* List of maybe swapped mm's. These 920 * are globally strung together off 921 * init_mm.mmlist, and are protected 922 * by mmlist_lock 923 */ 924 #ifdef CONFIG_PER_VMA_LOCK 925 /* 926 * This field has lock-like semantics, meaning it is sometimes 927 * accessed with ACQUIRE/RELEASE semantics. 928 * Roughly speaking, incrementing the sequence number is 929 * equivalent to releasing locks on VMAs; reading the sequence 930 * number can be part of taking a read lock on a VMA. 931 * Incremented every time mmap_lock is write-locked/unlocked. 932 * Initialized to 0, therefore odd values indicate mmap_lock 933 * is write-locked and even values that it's released. 934 * 935 * Can be modified under write mmap_lock using RELEASE 936 * semantics. 937 * Can be read with no other protection when holding write 938 * mmap_lock. 939 * Can be read with ACQUIRE semantics if not holding write 940 * mmap_lock. 941 */ 942 seqcount_t mm_lock_seq; 943 #endif 944 945 946 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 947 unsigned long hiwater_vm; /* High-water virtual memory usage */ 948 949 unsigned long total_vm; /* Total pages mapped */ 950 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 951 atomic64_t pinned_vm; /* Refcount permanently increased */ 952 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 953 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 954 unsigned long stack_vm; /* VM_STACK */ 955 unsigned long def_flags; 956 957 /** 958 * @write_protect_seq: Locked when any thread is write 959 * protecting pages mapped by this mm to enforce a later COW, 960 * for instance during page table copying for fork(). 961 */ 962 seqcount_t write_protect_seq; 963 964 spinlock_t arg_lock; /* protect the below fields */ 965 966 unsigned long start_code, end_code, start_data, end_data; 967 unsigned long start_brk, brk, start_stack; 968 unsigned long arg_start, arg_end, env_start, env_end; 969 970 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 971 972 struct percpu_counter rss_stat[NR_MM_COUNTERS]; 973 974 struct linux_binfmt *binfmt; 975 976 /* Architecture-specific MM context */ 977 mm_context_t context; 978 979 unsigned long flags; /* Must use atomic bitops to access */ 980 981 #ifdef CONFIG_AIO 982 spinlock_t ioctx_lock; 983 struct kioctx_table __rcu *ioctx_table; 984 #endif 985 #ifdef CONFIG_MEMCG 986 /* 987 * "owner" points to a task that is regarded as the canonical 988 * user/owner of this mm. All of the following must be true in 989 * order for it to be changed: 990 * 991 * current == mm->owner 992 * current->mm != mm 993 * new_owner->mm == mm 994 * new_owner->alloc_lock is held 995 */ 996 struct task_struct __rcu *owner; 997 #endif 998 struct user_namespace *user_ns; 999 1000 /* store ref to file /proc/<pid>/exe symlink points to */ 1001 struct file __rcu *exe_file; 1002 #ifdef CONFIG_MMU_NOTIFIER 1003 struct mmu_notifier_subscriptions *notifier_subscriptions; 1004 #endif 1005 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !defined(CONFIG_SPLIT_PMD_PTLOCKS) 1006 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 1007 #endif 1008 #ifdef CONFIG_NUMA_BALANCING 1009 /* 1010 * numa_next_scan is the next time that PTEs will be remapped 1011 * PROT_NONE to trigger NUMA hinting faults; such faults gather 1012 * statistics and migrate pages to new nodes if necessary. 1013 */ 1014 unsigned long numa_next_scan; 1015 1016 /* Restart point for scanning and remapping PTEs. */ 1017 unsigned long numa_scan_offset; 1018 1019 /* numa_scan_seq prevents two threads remapping PTEs. */ 1020 int numa_scan_seq; 1021 #endif 1022 /* 1023 * An operation with batched TLB flushing is going on. Anything 1024 * that can move process memory needs to flush the TLB when 1025 * moving a PROT_NONE mapped page. 1026 */ 1027 atomic_t tlb_flush_pending; 1028 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 1029 /* See flush_tlb_batched_pending() */ 1030 atomic_t tlb_flush_batched; 1031 #endif 1032 struct uprobes_state uprobes_state; 1033 #ifdef CONFIG_PREEMPT_RT 1034 struct rcu_head delayed_drop; 1035 #endif 1036 #ifdef CONFIG_HUGETLB_PAGE 1037 atomic_long_t hugetlb_usage; 1038 #endif 1039 struct work_struct async_put_work; 1040 1041 #ifdef CONFIG_IOMMU_MM_DATA 1042 struct iommu_mm_data *iommu_mm; 1043 #endif 1044 #ifdef CONFIG_KSM 1045 /* 1046 * Represent how many pages of this process are involved in KSM 1047 * merging (not including ksm_zero_pages). 1048 */ 1049 unsigned long ksm_merging_pages; 1050 /* 1051 * Represent how many pages are checked for ksm merging 1052 * including merged and not merged. 1053 */ 1054 unsigned long ksm_rmap_items; 1055 /* 1056 * Represent how many empty pages are merged with kernel zero 1057 * pages when enabling KSM use_zero_pages. 1058 */ 1059 atomic_long_t ksm_zero_pages; 1060 #endif /* CONFIG_KSM */ 1061 #ifdef CONFIG_LRU_GEN_WALKS_MMU 1062 struct { 1063 /* this mm_struct is on lru_gen_mm_list */ 1064 struct list_head list; 1065 /* 1066 * Set when switching to this mm_struct, as a hint of 1067 * whether it has been used since the last time per-node 1068 * page table walkers cleared the corresponding bits. 1069 */ 1070 unsigned long bitmap; 1071 #ifdef CONFIG_MEMCG 1072 /* points to the memcg of "owner" above */ 1073 struct mem_cgroup *memcg; 1074 #endif 1075 } lru_gen; 1076 #endif /* CONFIG_LRU_GEN_WALKS_MMU */ 1077 } __randomize_layout; 1078 1079 /* 1080 * The mm_cpumask needs to be at the end of mm_struct, because it 1081 * is dynamically sized based on nr_cpu_ids. 1082 */ 1083 unsigned long cpu_bitmap[]; 1084 }; 1085 1086 #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \ 1087 MT_FLAGS_USE_RCU) 1088 extern struct mm_struct init_mm; 1089 1090 /* Pointer magic because the dynamic array size confuses some compilers. */ 1091 static inline void mm_init_cpumask(struct mm_struct *mm) 1092 { 1093 unsigned long cpu_bitmap = (unsigned long)mm; 1094 1095 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap); 1096 cpumask_clear((struct cpumask *)cpu_bitmap); 1097 } 1098 1099 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 1100 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 1101 { 1102 return (struct cpumask *)&mm->cpu_bitmap; 1103 } 1104 1105 #ifdef CONFIG_LRU_GEN 1106 1107 struct lru_gen_mm_list { 1108 /* mm_struct list for page table walkers */ 1109 struct list_head fifo; 1110 /* protects the list above */ 1111 spinlock_t lock; 1112 }; 1113 1114 #endif /* CONFIG_LRU_GEN */ 1115 1116 #ifdef CONFIG_LRU_GEN_WALKS_MMU 1117 1118 void lru_gen_add_mm(struct mm_struct *mm); 1119 void lru_gen_del_mm(struct mm_struct *mm); 1120 void lru_gen_migrate_mm(struct mm_struct *mm); 1121 1122 static inline void lru_gen_init_mm(struct mm_struct *mm) 1123 { 1124 INIT_LIST_HEAD(&mm->lru_gen.list); 1125 mm->lru_gen.bitmap = 0; 1126 #ifdef CONFIG_MEMCG 1127 mm->lru_gen.memcg = NULL; 1128 #endif 1129 } 1130 1131 static inline void lru_gen_use_mm(struct mm_struct *mm) 1132 { 1133 /* 1134 * When the bitmap is set, page reclaim knows this mm_struct has been 1135 * used since the last time it cleared the bitmap. So it might be worth 1136 * walking the page tables of this mm_struct to clear the accessed bit. 1137 */ 1138 WRITE_ONCE(mm->lru_gen.bitmap, -1); 1139 } 1140 1141 #else /* !CONFIG_LRU_GEN_WALKS_MMU */ 1142 1143 static inline void lru_gen_add_mm(struct mm_struct *mm) 1144 { 1145 } 1146 1147 static inline void lru_gen_del_mm(struct mm_struct *mm) 1148 { 1149 } 1150 1151 static inline void lru_gen_migrate_mm(struct mm_struct *mm) 1152 { 1153 } 1154 1155 static inline void lru_gen_init_mm(struct mm_struct *mm) 1156 { 1157 } 1158 1159 static inline void lru_gen_use_mm(struct mm_struct *mm) 1160 { 1161 } 1162 1163 #endif /* CONFIG_LRU_GEN_WALKS_MMU */ 1164 1165 struct vma_iterator { 1166 struct ma_state mas; 1167 }; 1168 1169 #define VMA_ITERATOR(name, __mm, __addr) \ 1170 struct vma_iterator name = { \ 1171 .mas = { \ 1172 .tree = &(__mm)->mm_mt, \ 1173 .index = __addr, \ 1174 .node = NULL, \ 1175 .status = ma_start, \ 1176 }, \ 1177 } 1178 1179 static inline void vma_iter_init(struct vma_iterator *vmi, 1180 struct mm_struct *mm, unsigned long addr) 1181 { 1182 mas_init(&vmi->mas, &mm->mm_mt, addr); 1183 } 1184 1185 #ifdef CONFIG_SCHED_MM_CID 1186 1187 enum mm_cid_state { 1188 MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */ 1189 MM_CID_LAZY_PUT = (1U << 31), 1190 }; 1191 1192 static inline bool mm_cid_is_unset(int cid) 1193 { 1194 return cid == MM_CID_UNSET; 1195 } 1196 1197 static inline bool mm_cid_is_lazy_put(int cid) 1198 { 1199 return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT); 1200 } 1201 1202 static inline bool mm_cid_is_valid(int cid) 1203 { 1204 return !(cid & MM_CID_LAZY_PUT); 1205 } 1206 1207 static inline int mm_cid_set_lazy_put(int cid) 1208 { 1209 return cid | MM_CID_LAZY_PUT; 1210 } 1211 1212 static inline int mm_cid_clear_lazy_put(int cid) 1213 { 1214 return cid & ~MM_CID_LAZY_PUT; 1215 } 1216 1217 /* 1218 * mm_cpus_allowed: Union of all mm's threads allowed CPUs. 1219 */ 1220 static inline cpumask_t *mm_cpus_allowed(struct mm_struct *mm) 1221 { 1222 unsigned long bitmap = (unsigned long)mm; 1223 1224 bitmap += offsetof(struct mm_struct, cpu_bitmap); 1225 /* Skip cpu_bitmap */ 1226 bitmap += cpumask_size(); 1227 return (struct cpumask *)bitmap; 1228 } 1229 1230 /* Accessor for struct mm_struct's cidmask. */ 1231 static inline cpumask_t *mm_cidmask(struct mm_struct *mm) 1232 { 1233 unsigned long cid_bitmap = (unsigned long)mm_cpus_allowed(mm); 1234 1235 /* Skip mm_cpus_allowed */ 1236 cid_bitmap += cpumask_size(); 1237 return (struct cpumask *)cid_bitmap; 1238 } 1239 1240 static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p) 1241 { 1242 int i; 1243 1244 for_each_possible_cpu(i) { 1245 struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i); 1246 1247 pcpu_cid->cid = MM_CID_UNSET; 1248 pcpu_cid->recent_cid = MM_CID_UNSET; 1249 pcpu_cid->time = 0; 1250 } 1251 mm->nr_cpus_allowed = p->nr_cpus_allowed; 1252 atomic_set(&mm->max_nr_cid, 0); 1253 raw_spin_lock_init(&mm->cpus_allowed_lock); 1254 cpumask_copy(mm_cpus_allowed(mm), &p->cpus_mask); 1255 cpumask_clear(mm_cidmask(mm)); 1256 } 1257 1258 static inline int mm_alloc_cid_noprof(struct mm_struct *mm, struct task_struct *p) 1259 { 1260 mm->pcpu_cid = alloc_percpu_noprof(struct mm_cid); 1261 if (!mm->pcpu_cid) 1262 return -ENOMEM; 1263 mm_init_cid(mm, p); 1264 return 0; 1265 } 1266 #define mm_alloc_cid(...) alloc_hooks(mm_alloc_cid_noprof(__VA_ARGS__)) 1267 1268 static inline void mm_destroy_cid(struct mm_struct *mm) 1269 { 1270 free_percpu(mm->pcpu_cid); 1271 mm->pcpu_cid = NULL; 1272 } 1273 1274 static inline unsigned int mm_cid_size(void) 1275 { 1276 return 2 * cpumask_size(); /* mm_cpus_allowed(), mm_cidmask(). */ 1277 } 1278 1279 static inline void mm_set_cpus_allowed(struct mm_struct *mm, const struct cpumask *cpumask) 1280 { 1281 struct cpumask *mm_allowed = mm_cpus_allowed(mm); 1282 1283 if (!mm) 1284 return; 1285 /* The mm_cpus_allowed is the union of each thread allowed CPUs masks. */ 1286 raw_spin_lock(&mm->cpus_allowed_lock); 1287 cpumask_or(mm_allowed, mm_allowed, cpumask); 1288 WRITE_ONCE(mm->nr_cpus_allowed, cpumask_weight(mm_allowed)); 1289 raw_spin_unlock(&mm->cpus_allowed_lock); 1290 } 1291 #else /* CONFIG_SCHED_MM_CID */ 1292 static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p) { } 1293 static inline int mm_alloc_cid(struct mm_struct *mm, struct task_struct *p) { return 0; } 1294 static inline void mm_destroy_cid(struct mm_struct *mm) { } 1295 1296 static inline unsigned int mm_cid_size(void) 1297 { 1298 return 0; 1299 } 1300 static inline void mm_set_cpus_allowed(struct mm_struct *mm, const struct cpumask *cpumask) { } 1301 #endif /* CONFIG_SCHED_MM_CID */ 1302 1303 struct mmu_gather; 1304 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); 1305 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); 1306 extern void tlb_finish_mmu(struct mmu_gather *tlb); 1307 1308 struct vm_fault; 1309 1310 /** 1311 * typedef vm_fault_t - Return type for page fault handlers. 1312 * 1313 * Page fault handlers return a bitmask of %VM_FAULT values. 1314 */ 1315 typedef __bitwise unsigned int vm_fault_t; 1316 1317 /** 1318 * enum vm_fault_reason - Page fault handlers return a bitmask of 1319 * these values to tell the core VM what happened when handling the 1320 * fault. Used to decide whether a process gets delivered SIGBUS or 1321 * just gets major/minor fault counters bumped up. 1322 * 1323 * @VM_FAULT_OOM: Out Of Memory 1324 * @VM_FAULT_SIGBUS: Bad access 1325 * @VM_FAULT_MAJOR: Page read from storage 1326 * @VM_FAULT_HWPOISON: Hit poisoned small page 1327 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded 1328 * in upper bits 1329 * @VM_FAULT_SIGSEGV: segmentation fault 1330 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page 1331 * @VM_FAULT_LOCKED: ->fault locked the returned page 1332 * @VM_FAULT_RETRY: ->fault blocked, must retry 1333 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small 1334 * @VM_FAULT_DONE_COW: ->fault has fully handled COW 1335 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs 1336 * fsync() to complete (for synchronous page faults 1337 * in DAX) 1338 * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released 1339 * @VM_FAULT_HINDEX_MASK: mask HINDEX value 1340 * 1341 */ 1342 enum vm_fault_reason { 1343 VM_FAULT_OOM = (__force vm_fault_t)0x000001, 1344 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, 1345 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, 1346 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, 1347 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, 1348 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, 1349 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, 1350 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, 1351 VM_FAULT_RETRY = (__force vm_fault_t)0x000400, 1352 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, 1353 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, 1354 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, 1355 VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000, 1356 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, 1357 }; 1358 1359 /* Encode hstate index for a hwpoisoned large page */ 1360 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) 1361 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf) 1362 1363 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ 1364 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ 1365 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) 1366 1367 #define VM_FAULT_RESULT_TRACE \ 1368 { VM_FAULT_OOM, "OOM" }, \ 1369 { VM_FAULT_SIGBUS, "SIGBUS" }, \ 1370 { VM_FAULT_MAJOR, "MAJOR" }, \ 1371 { VM_FAULT_HWPOISON, "HWPOISON" }, \ 1372 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ 1373 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ 1374 { VM_FAULT_NOPAGE, "NOPAGE" }, \ 1375 { VM_FAULT_LOCKED, "LOCKED" }, \ 1376 { VM_FAULT_RETRY, "RETRY" }, \ 1377 { VM_FAULT_FALLBACK, "FALLBACK" }, \ 1378 { VM_FAULT_DONE_COW, "DONE_COW" }, \ 1379 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \ 1380 { VM_FAULT_COMPLETED, "COMPLETED" } 1381 1382 struct vm_special_mapping { 1383 const char *name; /* The name, e.g. "[vdso]". */ 1384 1385 /* 1386 * If .fault is not provided, this points to a 1387 * NULL-terminated array of pages that back the special mapping. 1388 * 1389 * This must not be NULL unless .fault is provided. 1390 */ 1391 struct page **pages; 1392 1393 /* 1394 * If non-NULL, then this is called to resolve page faults 1395 * on the special mapping. If used, .pages is not checked. 1396 */ 1397 vm_fault_t (*fault)(const struct vm_special_mapping *sm, 1398 struct vm_area_struct *vma, 1399 struct vm_fault *vmf); 1400 1401 int (*mremap)(const struct vm_special_mapping *sm, 1402 struct vm_area_struct *new_vma); 1403 1404 void (*close)(const struct vm_special_mapping *sm, 1405 struct vm_area_struct *vma); 1406 }; 1407 1408 enum tlb_flush_reason { 1409 TLB_FLUSH_ON_TASK_SWITCH, 1410 TLB_REMOTE_SHOOTDOWN, 1411 TLB_LOCAL_SHOOTDOWN, 1412 TLB_LOCAL_MM_SHOOTDOWN, 1413 TLB_REMOTE_SEND_IPI, 1414 TLB_REMOTE_WRONG_CPU, 1415 NR_TLB_FLUSH_REASONS, 1416 }; 1417 1418 /** 1419 * enum fault_flag - Fault flag definitions. 1420 * @FAULT_FLAG_WRITE: Fault was a write fault. 1421 * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE. 1422 * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked. 1423 * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_lock and wait when retrying. 1424 * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region. 1425 * @FAULT_FLAG_TRIED: The fault has been tried once. 1426 * @FAULT_FLAG_USER: The fault originated in userspace. 1427 * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. 1428 * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. 1429 * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. 1430 * @FAULT_FLAG_UNSHARE: The fault is an unsharing request to break COW in a 1431 * COW mapping, making sure that an exclusive anon page is 1432 * mapped after the fault. 1433 * @FAULT_FLAG_ORIG_PTE_VALID: whether the fault has vmf->orig_pte cached. 1434 * We should only access orig_pte if this flag set. 1435 * @FAULT_FLAG_VMA_LOCK: The fault is handled under VMA lock. 1436 * 1437 * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify 1438 * whether we would allow page faults to retry by specifying these two 1439 * fault flags correctly. Currently there can be three legal combinations: 1440 * 1441 * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and 1442 * this is the first try 1443 * 1444 * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and 1445 * we've already tried at least once 1446 * 1447 * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry 1448 * 1449 * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never 1450 * be used. Note that page faults can be allowed to retry for multiple times, 1451 * in which case we'll have an initial fault with flags (a) then later on 1452 * continuous faults with flags (b). We should always try to detect pending 1453 * signals before a retry to make sure the continuous page faults can still be 1454 * interrupted if necessary. 1455 * 1456 * The combination FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE is illegal. 1457 * FAULT_FLAG_UNSHARE is ignored and treated like an ordinary read fault when 1458 * applied to mappings that are not COW mappings. 1459 */ 1460 enum fault_flag { 1461 FAULT_FLAG_WRITE = 1 << 0, 1462 FAULT_FLAG_MKWRITE = 1 << 1, 1463 FAULT_FLAG_ALLOW_RETRY = 1 << 2, 1464 FAULT_FLAG_RETRY_NOWAIT = 1 << 3, 1465 FAULT_FLAG_KILLABLE = 1 << 4, 1466 FAULT_FLAG_TRIED = 1 << 5, 1467 FAULT_FLAG_USER = 1 << 6, 1468 FAULT_FLAG_REMOTE = 1 << 7, 1469 FAULT_FLAG_INSTRUCTION = 1 << 8, 1470 FAULT_FLAG_INTERRUPTIBLE = 1 << 9, 1471 FAULT_FLAG_UNSHARE = 1 << 10, 1472 FAULT_FLAG_ORIG_PTE_VALID = 1 << 11, 1473 FAULT_FLAG_VMA_LOCK = 1 << 12, 1474 }; 1475 1476 typedef unsigned int __bitwise zap_flags_t; 1477 1478 /* Flags for clear_young_dirty_ptes(). */ 1479 typedef int __bitwise cydp_t; 1480 1481 /* Clear the access bit */ 1482 #define CYDP_CLEAR_YOUNG ((__force cydp_t)BIT(0)) 1483 1484 /* Clear the dirty bit */ 1485 #define CYDP_CLEAR_DIRTY ((__force cydp_t)BIT(1)) 1486 1487 /* 1488 * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each 1489 * other. Here is what they mean, and how to use them: 1490 * 1491 * 1492 * FIXME: For pages which are part of a filesystem, mappings are subject to the 1493 * lifetime enforced by the filesystem and we need guarantees that longterm 1494 * users like RDMA and V4L2 only establish mappings which coordinate usage with 1495 * the filesystem. Ideas for this coordination include revoking the longterm 1496 * pin, delaying writeback, bounce buffer page writeback, etc. As FS DAX was 1497 * added after the problem with filesystems was found FS DAX VMAs are 1498 * specifically failed. Filesystem pages are still subject to bugs and use of 1499 * FOLL_LONGTERM should be avoided on those pages. 1500 * 1501 * In the CMA case: long term pins in a CMA region would unnecessarily fragment 1502 * that region. And so, CMA attempts to migrate the page before pinning, when 1503 * FOLL_LONGTERM is specified. 1504 * 1505 * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount, 1506 * but an additional pin counting system) will be invoked. This is intended for 1507 * anything that gets a page reference and then touches page data (for example, 1508 * Direct IO). This lets the filesystem know that some non-file-system entity is 1509 * potentially changing the pages' data. In contrast to FOLL_GET (whose pages 1510 * are released via put_page()), FOLL_PIN pages must be released, ultimately, by 1511 * a call to unpin_user_page(). 1512 * 1513 * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different 1514 * and separate refcounting mechanisms, however, and that means that each has 1515 * its own acquire and release mechanisms: 1516 * 1517 * FOLL_GET: get_user_pages*() to acquire, and put_page() to release. 1518 * 1519 * FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release. 1520 * 1521 * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call. 1522 * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based 1523 * calls applied to them, and that's perfectly OK. This is a constraint on the 1524 * callers, not on the pages.) 1525 * 1526 * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never 1527 * directly by the caller. That's in order to help avoid mismatches when 1528 * releasing pages: get_user_pages*() pages must be released via put_page(), 1529 * while pin_user_pages*() pages must be released via unpin_user_page(). 1530 * 1531 * Please see Documentation/core-api/pin_user_pages.rst for more information. 1532 */ 1533 1534 enum { 1535 /* check pte is writable */ 1536 FOLL_WRITE = 1 << 0, 1537 /* do get_page on page */ 1538 FOLL_GET = 1 << 1, 1539 /* give error on hole if it would be zero */ 1540 FOLL_DUMP = 1 << 2, 1541 /* get_user_pages read/write w/o permission */ 1542 FOLL_FORCE = 1 << 3, 1543 /* 1544 * if a disk transfer is needed, start the IO and return without waiting 1545 * upon it 1546 */ 1547 FOLL_NOWAIT = 1 << 4, 1548 /* do not fault in pages */ 1549 FOLL_NOFAULT = 1 << 5, 1550 /* check page is hwpoisoned */ 1551 FOLL_HWPOISON = 1 << 6, 1552 /* don't do file mappings */ 1553 FOLL_ANON = 1 << 7, 1554 /* 1555 * FOLL_LONGTERM indicates that the page will be held for an indefinite 1556 * time period _often_ under userspace control. This is in contrast to 1557 * iov_iter_get_pages(), whose usages are transient. 1558 */ 1559 FOLL_LONGTERM = 1 << 8, 1560 /* split huge pmd before returning */ 1561 FOLL_SPLIT_PMD = 1 << 9, 1562 /* allow returning PCI P2PDMA pages */ 1563 FOLL_PCI_P2PDMA = 1 << 10, 1564 /* allow interrupts from generic signals */ 1565 FOLL_INTERRUPTIBLE = 1 << 11, 1566 /* 1567 * Always honor (trigger) NUMA hinting faults. 1568 * 1569 * FOLL_WRITE implicitly honors NUMA hinting faults because a 1570 * PROT_NONE-mapped page is not writable (exceptions with FOLL_FORCE 1571 * apply). get_user_pages_fast_only() always implicitly honors NUMA 1572 * hinting faults. 1573 */ 1574 FOLL_HONOR_NUMA_FAULT = 1 << 12, 1575 1576 /* See also internal only FOLL flags in mm/internal.h */ 1577 }; 1578 1579 /* mm flags */ 1580 1581 /* 1582 * The first two bits represent core dump modes for set-user-ID, 1583 * the modes are SUID_DUMP_* defined in linux/sched/coredump.h 1584 */ 1585 #define MMF_DUMPABLE_BITS 2 1586 #define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1) 1587 /* coredump filter bits */ 1588 #define MMF_DUMP_ANON_PRIVATE 2 1589 #define MMF_DUMP_ANON_SHARED 3 1590 #define MMF_DUMP_MAPPED_PRIVATE 4 1591 #define MMF_DUMP_MAPPED_SHARED 5 1592 #define MMF_DUMP_ELF_HEADERS 6 1593 #define MMF_DUMP_HUGETLB_PRIVATE 7 1594 #define MMF_DUMP_HUGETLB_SHARED 8 1595 #define MMF_DUMP_DAX_PRIVATE 9 1596 #define MMF_DUMP_DAX_SHARED 10 1597 1598 #define MMF_DUMP_FILTER_SHIFT MMF_DUMPABLE_BITS 1599 #define MMF_DUMP_FILTER_BITS 9 1600 #define MMF_DUMP_FILTER_MASK \ 1601 (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT) 1602 #define MMF_DUMP_FILTER_DEFAULT \ 1603 ((1 << MMF_DUMP_ANON_PRIVATE) | (1 << MMF_DUMP_ANON_SHARED) |\ 1604 (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF) 1605 1606 #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS 1607 # define MMF_DUMP_MASK_DEFAULT_ELF (1 << MMF_DUMP_ELF_HEADERS) 1608 #else 1609 # define MMF_DUMP_MASK_DEFAULT_ELF 0 1610 #endif 1611 /* leave room for more dump flags */ 1612 #define MMF_VM_MERGEABLE 16 /* KSM may merge identical pages */ 1613 #define MMF_VM_HUGEPAGE 17 /* set when mm is available for khugepaged */ 1614 1615 /* 1616 * This one-shot flag is dropped due to necessity of changing exe once again 1617 * on NFS restore 1618 */ 1619 //#define MMF_EXE_FILE_CHANGED 18 /* see prctl_set_mm_exe_file() */ 1620 1621 #define MMF_HAS_UPROBES 19 /* has uprobes */ 1622 #define MMF_RECALC_UPROBES 20 /* MMF_HAS_UPROBES can be wrong */ 1623 #define MMF_OOM_SKIP 21 /* mm is of no interest for the OOM killer */ 1624 #define MMF_UNSTABLE 22 /* mm is unstable for copy_from_user */ 1625 #define MMF_HUGE_ZERO_PAGE 23 /* mm has ever used the global huge zero page */ 1626 #define MMF_DISABLE_THP 24 /* disable THP for all VMAs */ 1627 #define MMF_DISABLE_THP_MASK (1 << MMF_DISABLE_THP) 1628 #define MMF_OOM_REAP_QUEUED 25 /* mm was queued for oom_reaper */ 1629 #define MMF_MULTIPROCESS 26 /* mm is shared between processes */ 1630 /* 1631 * MMF_HAS_PINNED: Whether this mm has pinned any pages. This can be either 1632 * replaced in the future by mm.pinned_vm when it becomes stable, or grow into 1633 * a counter on its own. We're aggresive on this bit for now: even if the 1634 * pinned pages were unpinned later on, we'll still keep this bit set for the 1635 * lifecycle of this mm, just for simplicity. 1636 */ 1637 #define MMF_HAS_PINNED 27 /* FOLL_PIN has run, never cleared */ 1638 1639 #define MMF_HAS_MDWE 28 1640 #define MMF_HAS_MDWE_MASK (1 << MMF_HAS_MDWE) 1641 1642 1643 #define MMF_HAS_MDWE_NO_INHERIT 29 1644 1645 #define MMF_VM_MERGE_ANY 30 1646 #define MMF_VM_MERGE_ANY_MASK (1 << MMF_VM_MERGE_ANY) 1647 1648 #define MMF_TOPDOWN 31 /* mm searches top down by default */ 1649 #define MMF_TOPDOWN_MASK (1 << MMF_TOPDOWN) 1650 1651 #define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\ 1652 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\ 1653 MMF_VM_MERGE_ANY_MASK | MMF_TOPDOWN_MASK) 1654 1655 static inline unsigned long mmf_init_flags(unsigned long flags) 1656 { 1657 if (flags & (1UL << MMF_HAS_MDWE_NO_INHERIT)) 1658 flags &= ~((1UL << MMF_HAS_MDWE) | 1659 (1UL << MMF_HAS_MDWE_NO_INHERIT)); 1660 return flags & MMF_INIT_MASK; 1661 } 1662 1663 #endif /* _LINUX_MM_TYPES_H */ 1664