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/list.h> 9 #include <linux/spinlock.h> 10 #include <linux/rbtree.h> 11 #include <linux/rwsem.h> 12 #include <linux/completion.h> 13 #include <linux/cpumask.h> 14 #include <linux/uprobes.h> 15 #include <linux/rcupdate.h> 16 #include <linux/page-flags-layout.h> 17 #include <linux/workqueue.h> 18 #include <linux/seqlock.h> 19 20 #include <asm/mmu.h> 21 22 #ifndef AT_VECTOR_SIZE_ARCH 23 #define AT_VECTOR_SIZE_ARCH 0 24 #endif 25 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) 26 27 #define INIT_PASID 0 28 29 struct address_space; 30 struct mem_cgroup; 31 32 /* 33 * Each physical page in the system has a struct page associated with 34 * it to keep track of whatever it is we are using the page for at the 35 * moment. Note that we have no way to track which tasks are using 36 * a page, though if it is a pagecache page, rmap structures can tell us 37 * who is mapping it. 38 * 39 * If you allocate the page using alloc_pages(), you can use some of the 40 * space in struct page for your own purposes. The five words in the main 41 * union are available, except for bit 0 of the first word which must be 42 * kept clear. Many users use this word to store a pointer to an object 43 * which is guaranteed to be aligned. If you use the same storage as 44 * page->mapping, you must restore it to NULL before freeing the page. 45 * 46 * If your page will not be mapped to userspace, you can also use the four 47 * bytes in the mapcount union, but you must call page_mapcount_reset() 48 * before freeing it. 49 * 50 * If you want to use the refcount field, it must be used in such a way 51 * that other CPUs temporarily incrementing and then decrementing the 52 * refcount does not cause problems. On receiving the page from 53 * alloc_pages(), the refcount will be positive. 54 * 55 * If you allocate pages of order > 0, you can use some of the fields 56 * in each subpage, but you may need to restore some of their values 57 * afterwards. 58 * 59 * SLUB uses cmpxchg_double() to atomically update its freelist and 60 * counters. That requires that freelist & counters be adjacent and 61 * double-word aligned. We align all struct pages to double-word 62 * boundaries, and ensure that 'freelist' is aligned within the 63 * struct. 64 */ 65 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 66 #define _struct_page_alignment __aligned(2 * sizeof(unsigned long)) 67 #else 68 #define _struct_page_alignment 69 #endif 70 71 struct page { 72 unsigned long flags; /* Atomic flags, some possibly 73 * updated asynchronously */ 74 /* 75 * Five words (20/40 bytes) are available in this union. 76 * WARNING: bit 0 of the first word is used for PageTail(). That 77 * means the other users of this union MUST NOT use the bit to 78 * avoid collision and false-positive PageTail(). 79 */ 80 union { 81 struct { /* Page cache and anonymous pages */ 82 /** 83 * @lru: Pageout list, eg. active_list protected by 84 * lruvec->lru_lock. Sometimes used as a generic list 85 * by the page owner. 86 */ 87 struct list_head lru; 88 /* See page-flags.h for PAGE_MAPPING_FLAGS */ 89 struct address_space *mapping; 90 pgoff_t index; /* Our offset within mapping. */ 91 /** 92 * @private: Mapping-private opaque data. 93 * Usually used for buffer_heads if PagePrivate. 94 * Used for swp_entry_t if PageSwapCache. 95 * Indicates order in the buddy system if PageBuddy. 96 */ 97 unsigned long private; 98 }; 99 struct { /* page_pool used by netstack */ 100 /** 101 * @pp_magic: magic value to avoid recycling non 102 * page_pool allocated pages. 103 */ 104 unsigned long pp_magic; 105 struct page_pool *pp; 106 unsigned long _pp_mapping_pad; 107 unsigned long dma_addr; 108 atomic_long_t pp_frag_count; 109 }; 110 struct { /* slab, slob and slub */ 111 union { 112 struct list_head slab_list; 113 struct { /* Partial pages */ 114 struct page *next; 115 #ifdef CONFIG_64BIT 116 int pages; /* Nr of pages left */ 117 #else 118 short int pages; 119 #endif 120 }; 121 }; 122 struct kmem_cache *slab_cache; /* not slob */ 123 /* Double-word boundary */ 124 void *freelist; /* first free object */ 125 union { 126 void *s_mem; /* slab: first object */ 127 unsigned long counters; /* SLUB */ 128 struct { /* SLUB */ 129 unsigned inuse:16; 130 unsigned objects:15; 131 unsigned frozen:1; 132 }; 133 }; 134 }; 135 struct { /* Tail pages of compound page */ 136 unsigned long compound_head; /* Bit zero is set */ 137 138 /* First tail page only */ 139 unsigned char compound_dtor; 140 unsigned char compound_order; 141 atomic_t compound_mapcount; 142 unsigned int compound_nr; /* 1 << compound_order */ 143 }; 144 struct { /* Second tail page of compound page */ 145 unsigned long _compound_pad_1; /* compound_head */ 146 atomic_t hpage_pinned_refcount; 147 /* For both global and memcg */ 148 struct list_head deferred_list; 149 }; 150 struct { /* Page table pages */ 151 unsigned long _pt_pad_1; /* compound_head */ 152 pgtable_t pmd_huge_pte; /* protected by page->ptl */ 153 unsigned long _pt_pad_2; /* mapping */ 154 union { 155 struct mm_struct *pt_mm; /* x86 pgds only */ 156 atomic_t pt_frag_refcount; /* powerpc */ 157 }; 158 #if ALLOC_SPLIT_PTLOCKS 159 spinlock_t *ptl; 160 #else 161 spinlock_t ptl; 162 #endif 163 }; 164 struct { /* ZONE_DEVICE pages */ 165 /** @pgmap: Points to the hosting device page map. */ 166 struct dev_pagemap *pgmap; 167 void *zone_device_data; 168 /* 169 * ZONE_DEVICE private pages are counted as being 170 * mapped so the next 3 words hold the mapping, index, 171 * and private fields from the source anonymous or 172 * page cache page while the page is migrated to device 173 * private memory. 174 * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also 175 * use the mapping, index, and private fields when 176 * pmem backed DAX files are mapped. 177 */ 178 }; 179 180 /** @rcu_head: You can use this to free a page by RCU. */ 181 struct rcu_head rcu_head; 182 }; 183 184 union { /* This union is 4 bytes in size. */ 185 /* 186 * If the page can be mapped to userspace, encodes the number 187 * of times this page is referenced by a page table. 188 */ 189 atomic_t _mapcount; 190 191 /* 192 * If the page is neither PageSlab nor mappable to userspace, 193 * the value stored here may help determine what this page 194 * is used for. See page-flags.h for a list of page types 195 * which are currently stored here. 196 */ 197 unsigned int page_type; 198 199 unsigned int active; /* SLAB */ 200 int units; /* SLOB */ 201 }; 202 203 /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */ 204 atomic_t _refcount; 205 206 #ifdef CONFIG_MEMCG 207 unsigned long memcg_data; 208 #endif 209 210 /* 211 * On machines where all RAM is mapped into kernel address space, 212 * we can simply calculate the virtual address. On machines with 213 * highmem some memory is mapped into kernel virtual memory 214 * dynamically, so we need a place to store that address. 215 * Note that this field could be 16 bits on x86 ... ;) 216 * 217 * Architectures with slow multiplication can define 218 * WANT_PAGE_VIRTUAL in asm/page.h 219 */ 220 #if defined(WANT_PAGE_VIRTUAL) 221 void *virtual; /* Kernel virtual address (NULL if 222 not kmapped, ie. highmem) */ 223 #endif /* WANT_PAGE_VIRTUAL */ 224 225 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 226 int _last_cpupid; 227 #endif 228 } _struct_page_alignment; 229 230 /** 231 * struct folio - Represents a contiguous set of bytes. 232 * @flags: Identical to the page flags. 233 * @lru: Least Recently Used list; tracks how recently this folio was used. 234 * @mapping: The file this page belongs to, or refers to the anon_vma for 235 * anonymous memory. 236 * @index: Offset within the file, in units of pages. For anonymous memory, 237 * this is the index from the beginning of the mmap. 238 * @private: Filesystem per-folio data (see folio_attach_private()). 239 * Used for swp_entry_t if folio_test_swapcache(). 240 * @_mapcount: Do not access this member directly. Use folio_mapcount() to 241 * find out how many times this folio is mapped by userspace. 242 * @_refcount: Do not access this member directly. Use folio_ref_count() 243 * to find how many references there are to this folio. 244 * @memcg_data: Memory Control Group data. 245 * 246 * A folio is a physically, virtually and logically contiguous set 247 * of bytes. It is a power-of-two in size, and it is aligned to that 248 * same power-of-two. It is at least as large as %PAGE_SIZE. If it is 249 * in the page cache, it is at a file offset which is a multiple of that 250 * power-of-two. It may be mapped into userspace at an address which is 251 * at an arbitrary page offset, but its kernel virtual address is aligned 252 * to its size. 253 */ 254 struct folio { 255 /* private: don't document the anon union */ 256 union { 257 struct { 258 /* public: */ 259 unsigned long flags; 260 struct list_head lru; 261 struct address_space *mapping; 262 pgoff_t index; 263 void *private; 264 atomic_t _mapcount; 265 atomic_t _refcount; 266 #ifdef CONFIG_MEMCG 267 unsigned long memcg_data; 268 #endif 269 /* private: the union with struct page is transitional */ 270 }; 271 struct page page; 272 }; 273 }; 274 275 static_assert(sizeof(struct page) == sizeof(struct folio)); 276 #define FOLIO_MATCH(pg, fl) \ 277 static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl)) 278 FOLIO_MATCH(flags, flags); 279 FOLIO_MATCH(lru, lru); 280 FOLIO_MATCH(compound_head, lru); 281 FOLIO_MATCH(index, index); 282 FOLIO_MATCH(private, private); 283 FOLIO_MATCH(_mapcount, _mapcount); 284 FOLIO_MATCH(_refcount, _refcount); 285 #ifdef CONFIG_MEMCG 286 FOLIO_MATCH(memcg_data, memcg_data); 287 #endif 288 #undef FOLIO_MATCH 289 290 static inline atomic_t *folio_mapcount_ptr(struct folio *folio) 291 { 292 struct page *tail = &folio->page + 1; 293 return &tail->compound_mapcount; 294 } 295 296 static inline atomic_t *compound_mapcount_ptr(struct page *page) 297 { 298 return &page[1].compound_mapcount; 299 } 300 301 static inline atomic_t *compound_pincount_ptr(struct page *page) 302 { 303 return &page[2].hpage_pinned_refcount; 304 } 305 306 /* 307 * Used for sizing the vmemmap region on some architectures 308 */ 309 #define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) 310 311 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) 312 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) 313 314 /* 315 * page_private can be used on tail pages. However, PagePrivate is only 316 * checked by the VM on the head page. So page_private on the tail pages 317 * should be used for data that's ancillary to the head page (eg attaching 318 * buffer heads to tail pages after attaching buffer heads to the head page) 319 */ 320 #define page_private(page) ((page)->private) 321 322 static inline void set_page_private(struct page *page, unsigned long private) 323 { 324 page->private = private; 325 } 326 327 static inline void *folio_get_private(struct folio *folio) 328 { 329 return folio->private; 330 } 331 332 struct page_frag_cache { 333 void * va; 334 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) 335 __u16 offset; 336 __u16 size; 337 #else 338 __u32 offset; 339 #endif 340 /* we maintain a pagecount bias, so that we dont dirty cache line 341 * containing page->_refcount every time we allocate a fragment. 342 */ 343 unsigned int pagecnt_bias; 344 bool pfmemalloc; 345 }; 346 347 typedef unsigned long vm_flags_t; 348 349 /* 350 * A region containing a mapping of a non-memory backed file under NOMMU 351 * conditions. These are held in a global tree and are pinned by the VMAs that 352 * map parts of them. 353 */ 354 struct vm_region { 355 struct rb_node vm_rb; /* link in global region tree */ 356 vm_flags_t vm_flags; /* VMA vm_flags */ 357 unsigned long vm_start; /* start address of region */ 358 unsigned long vm_end; /* region initialised to here */ 359 unsigned long vm_top; /* region allocated to here */ 360 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 361 struct file *vm_file; /* the backing file or NULL */ 362 363 int vm_usage; /* region usage count (access under nommu_region_sem) */ 364 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 365 * this region */ 366 }; 367 368 #ifdef CONFIG_USERFAULTFD 369 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 370 struct vm_userfaultfd_ctx { 371 struct userfaultfd_ctx *ctx; 372 }; 373 #else /* CONFIG_USERFAULTFD */ 374 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 375 struct vm_userfaultfd_ctx {}; 376 #endif /* CONFIG_USERFAULTFD */ 377 378 /* 379 * This struct describes a virtual memory area. There is one of these 380 * per VM-area/task. A VM area is any part of the process virtual memory 381 * space that has a special rule for the page-fault handlers (ie a shared 382 * library, the executable area etc). 383 */ 384 struct vm_area_struct { 385 /* The first cache line has the info for VMA tree walking. */ 386 387 unsigned long vm_start; /* Our start address within vm_mm. */ 388 unsigned long vm_end; /* The first byte after our end address 389 within vm_mm. */ 390 391 /* linked list of VM areas per task, sorted by address */ 392 struct vm_area_struct *vm_next, *vm_prev; 393 394 struct rb_node vm_rb; 395 396 /* 397 * Largest free memory gap in bytes to the left of this VMA. 398 * Either between this VMA and vma->vm_prev, or between one of the 399 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps 400 * get_unmapped_area find a free area of the right size. 401 */ 402 unsigned long rb_subtree_gap; 403 404 /* Second cache line starts here. */ 405 406 struct mm_struct *vm_mm; /* The address space we belong to. */ 407 408 /* 409 * Access permissions of this VMA. 410 * See vmf_insert_mixed_prot() for discussion. 411 */ 412 pgprot_t vm_page_prot; 413 unsigned long vm_flags; /* Flags, see mm.h. */ 414 415 /* 416 * For areas with an address space and backing store, 417 * linkage into the address_space->i_mmap interval tree. 418 */ 419 struct { 420 struct rb_node rb; 421 unsigned long rb_subtree_last; 422 } shared; 423 424 /* 425 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 426 * list, after a COW of one of the file pages. A MAP_SHARED vma 427 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 428 * or brk vma (with NULL file) can only be in an anon_vma list. 429 */ 430 struct list_head anon_vma_chain; /* Serialized by mmap_lock & 431 * page_table_lock */ 432 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 433 434 /* Function pointers to deal with this struct. */ 435 const struct vm_operations_struct *vm_ops; 436 437 /* Information about our backing store: */ 438 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 439 units */ 440 struct file * vm_file; /* File we map to (can be NULL). */ 441 void * vm_private_data; /* was vm_pte (shared mem) */ 442 443 #ifdef CONFIG_SWAP 444 atomic_long_t swap_readahead_info; 445 #endif 446 #ifndef CONFIG_MMU 447 struct vm_region *vm_region; /* NOMMU mapping region */ 448 #endif 449 #ifdef CONFIG_NUMA 450 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 451 #endif 452 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 453 } __randomize_layout; 454 455 struct kioctx_table; 456 struct mm_struct { 457 struct { 458 struct vm_area_struct *mmap; /* list of VMAs */ 459 struct rb_root mm_rb; 460 u64 vmacache_seqnum; /* per-thread vmacache */ 461 #ifdef CONFIG_MMU 462 unsigned long (*get_unmapped_area) (struct file *filp, 463 unsigned long addr, unsigned long len, 464 unsigned long pgoff, unsigned long flags); 465 #endif 466 unsigned long mmap_base; /* base of mmap area */ 467 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ 468 #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES 469 /* Base addresses for compatible mmap() */ 470 unsigned long mmap_compat_base; 471 unsigned long mmap_compat_legacy_base; 472 #endif 473 unsigned long task_size; /* size of task vm space */ 474 unsigned long highest_vm_end; /* highest vma end address */ 475 pgd_t * pgd; 476 477 #ifdef CONFIG_MEMBARRIER 478 /** 479 * @membarrier_state: Flags controlling membarrier behavior. 480 * 481 * This field is close to @pgd to hopefully fit in the same 482 * cache-line, which needs to be touched by switch_mm(). 483 */ 484 atomic_t membarrier_state; 485 #endif 486 487 /** 488 * @mm_users: The number of users including userspace. 489 * 490 * Use mmget()/mmget_not_zero()/mmput() to modify. When this 491 * drops to 0 (i.e. when the task exits and there are no other 492 * temporary reference holders), we also release a reference on 493 * @mm_count (which may then free the &struct mm_struct if 494 * @mm_count also drops to 0). 495 */ 496 atomic_t mm_users; 497 498 /** 499 * @mm_count: The number of references to &struct mm_struct 500 * (@mm_users count as 1). 501 * 502 * Use mmgrab()/mmdrop() to modify. When this drops to 0, the 503 * &struct mm_struct is freed. 504 */ 505 atomic_t mm_count; 506 507 #ifdef CONFIG_MMU 508 atomic_long_t pgtables_bytes; /* PTE page table pages */ 509 #endif 510 int map_count; /* number of VMAs */ 511 512 spinlock_t page_table_lock; /* Protects page tables and some 513 * counters 514 */ 515 /* 516 * With some kernel config, the current mmap_lock's offset 517 * inside 'mm_struct' is at 0x120, which is very optimal, as 518 * its two hot fields 'count' and 'owner' sit in 2 different 519 * cachelines, and when mmap_lock is highly contended, both 520 * of the 2 fields will be accessed frequently, current layout 521 * will help to reduce cache bouncing. 522 * 523 * So please be careful with adding new fields before 524 * mmap_lock, which can easily push the 2 fields into one 525 * cacheline. 526 */ 527 struct rw_semaphore mmap_lock; 528 529 struct list_head mmlist; /* List of maybe swapped mm's. These 530 * are globally strung together off 531 * init_mm.mmlist, and are protected 532 * by mmlist_lock 533 */ 534 535 536 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 537 unsigned long hiwater_vm; /* High-water virtual memory usage */ 538 539 unsigned long total_vm; /* Total pages mapped */ 540 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 541 atomic64_t pinned_vm; /* Refcount permanently increased */ 542 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 543 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 544 unsigned long stack_vm; /* VM_STACK */ 545 unsigned long def_flags; 546 547 /** 548 * @write_protect_seq: Locked when any thread is write 549 * protecting pages mapped by this mm to enforce a later COW, 550 * for instance during page table copying for fork(). 551 */ 552 seqcount_t write_protect_seq; 553 554 spinlock_t arg_lock; /* protect the below fields */ 555 556 unsigned long start_code, end_code, start_data, end_data; 557 unsigned long start_brk, brk, start_stack; 558 unsigned long arg_start, arg_end, env_start, env_end; 559 560 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 561 562 /* 563 * Special counters, in some configurations protected by the 564 * page_table_lock, in other configurations by being atomic. 565 */ 566 struct mm_rss_stat rss_stat; 567 568 struct linux_binfmt *binfmt; 569 570 /* Architecture-specific MM context */ 571 mm_context_t context; 572 573 unsigned long flags; /* Must use atomic bitops to access */ 574 575 #ifdef CONFIG_AIO 576 spinlock_t ioctx_lock; 577 struct kioctx_table __rcu *ioctx_table; 578 #endif 579 #ifdef CONFIG_MEMCG 580 /* 581 * "owner" points to a task that is regarded as the canonical 582 * user/owner of this mm. All of the following must be true in 583 * order for it to be changed: 584 * 585 * current == mm->owner 586 * current->mm != mm 587 * new_owner->mm == mm 588 * new_owner->alloc_lock is held 589 */ 590 struct task_struct __rcu *owner; 591 #endif 592 struct user_namespace *user_ns; 593 594 /* store ref to file /proc/<pid>/exe symlink points to */ 595 struct file __rcu *exe_file; 596 #ifdef CONFIG_MMU_NOTIFIER 597 struct mmu_notifier_subscriptions *notifier_subscriptions; 598 #endif 599 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 600 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 601 #endif 602 #ifdef CONFIG_NUMA_BALANCING 603 /* 604 * numa_next_scan is the next time that the PTEs will be marked 605 * pte_numa. NUMA hinting faults will gather statistics and 606 * migrate pages to new nodes if necessary. 607 */ 608 unsigned long numa_next_scan; 609 610 /* Restart point for scanning and setting pte_numa */ 611 unsigned long numa_scan_offset; 612 613 /* numa_scan_seq prevents two threads setting pte_numa */ 614 int numa_scan_seq; 615 #endif 616 /* 617 * An operation with batched TLB flushing is going on. Anything 618 * that can move process memory needs to flush the TLB when 619 * moving a PROT_NONE or PROT_NUMA mapped page. 620 */ 621 atomic_t tlb_flush_pending; 622 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH 623 /* See flush_tlb_batched_pending() */ 624 bool tlb_flush_batched; 625 #endif 626 struct uprobes_state uprobes_state; 627 #ifdef CONFIG_PREEMPT_RT 628 struct rcu_head delayed_drop; 629 #endif 630 #ifdef CONFIG_HUGETLB_PAGE 631 atomic_long_t hugetlb_usage; 632 #endif 633 struct work_struct async_put_work; 634 635 #ifdef CONFIG_IOMMU_SUPPORT 636 u32 pasid; 637 #endif 638 } __randomize_layout; 639 640 /* 641 * The mm_cpumask needs to be at the end of mm_struct, because it 642 * is dynamically sized based on nr_cpu_ids. 643 */ 644 unsigned long cpu_bitmap[]; 645 }; 646 647 extern struct mm_struct init_mm; 648 649 /* Pointer magic because the dynamic array size confuses some compilers. */ 650 static inline void mm_init_cpumask(struct mm_struct *mm) 651 { 652 unsigned long cpu_bitmap = (unsigned long)mm; 653 654 cpu_bitmap += offsetof(struct mm_struct, cpu_bitmap); 655 cpumask_clear((struct cpumask *)cpu_bitmap); 656 } 657 658 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 659 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 660 { 661 return (struct cpumask *)&mm->cpu_bitmap; 662 } 663 664 struct mmu_gather; 665 extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); 666 extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); 667 extern void tlb_finish_mmu(struct mmu_gather *tlb); 668 669 static inline void init_tlb_flush_pending(struct mm_struct *mm) 670 { 671 atomic_set(&mm->tlb_flush_pending, 0); 672 } 673 674 static inline void inc_tlb_flush_pending(struct mm_struct *mm) 675 { 676 atomic_inc(&mm->tlb_flush_pending); 677 /* 678 * The only time this value is relevant is when there are indeed pages 679 * to flush. And we'll only flush pages after changing them, which 680 * requires the PTL. 681 * 682 * So the ordering here is: 683 * 684 * atomic_inc(&mm->tlb_flush_pending); 685 * spin_lock(&ptl); 686 * ... 687 * set_pte_at(); 688 * spin_unlock(&ptl); 689 * 690 * spin_lock(&ptl) 691 * mm_tlb_flush_pending(); 692 * .... 693 * spin_unlock(&ptl); 694 * 695 * flush_tlb_range(); 696 * atomic_dec(&mm->tlb_flush_pending); 697 * 698 * Where the increment if constrained by the PTL unlock, it thus 699 * ensures that the increment is visible if the PTE modification is 700 * visible. After all, if there is no PTE modification, nobody cares 701 * about TLB flushes either. 702 * 703 * This very much relies on users (mm_tlb_flush_pending() and 704 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and 705 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc 706 * locks (PPC) the unlock of one doesn't order against the lock of 707 * another PTL. 708 * 709 * The decrement is ordered by the flush_tlb_range(), such that 710 * mm_tlb_flush_pending() will not return false unless all flushes have 711 * completed. 712 */ 713 } 714 715 static inline void dec_tlb_flush_pending(struct mm_struct *mm) 716 { 717 /* 718 * See inc_tlb_flush_pending(). 719 * 720 * This cannot be smp_mb__before_atomic() because smp_mb() simply does 721 * not order against TLB invalidate completion, which is what we need. 722 * 723 * Therefore we must rely on tlb_flush_*() to guarantee order. 724 */ 725 atomic_dec(&mm->tlb_flush_pending); 726 } 727 728 static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 729 { 730 /* 731 * Must be called after having acquired the PTL; orders against that 732 * PTLs release and therefore ensures that if we observe the modified 733 * PTE we must also observe the increment from inc_tlb_flush_pending(). 734 * 735 * That is, it only guarantees to return true if there is a flush 736 * pending for _this_ PTL. 737 */ 738 return atomic_read(&mm->tlb_flush_pending); 739 } 740 741 static inline bool mm_tlb_flush_nested(struct mm_struct *mm) 742 { 743 /* 744 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL 745 * for which there is a TLB flush pending in order to guarantee 746 * we've seen both that PTE modification and the increment. 747 * 748 * (no requirement on actually still holding the PTL, that is irrelevant) 749 */ 750 return atomic_read(&mm->tlb_flush_pending) > 1; 751 } 752 753 struct vm_fault; 754 755 /** 756 * typedef vm_fault_t - Return type for page fault handlers. 757 * 758 * Page fault handlers return a bitmask of %VM_FAULT values. 759 */ 760 typedef __bitwise unsigned int vm_fault_t; 761 762 /** 763 * enum vm_fault_reason - Page fault handlers return a bitmask of 764 * these values to tell the core VM what happened when handling the 765 * fault. Used to decide whether a process gets delivered SIGBUS or 766 * just gets major/minor fault counters bumped up. 767 * 768 * @VM_FAULT_OOM: Out Of Memory 769 * @VM_FAULT_SIGBUS: Bad access 770 * @VM_FAULT_MAJOR: Page read from storage 771 * @VM_FAULT_WRITE: Special case for get_user_pages 772 * @VM_FAULT_HWPOISON: Hit poisoned small page 773 * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded 774 * in upper bits 775 * @VM_FAULT_SIGSEGV: segmentation fault 776 * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page 777 * @VM_FAULT_LOCKED: ->fault locked the returned page 778 * @VM_FAULT_RETRY: ->fault blocked, must retry 779 * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small 780 * @VM_FAULT_DONE_COW: ->fault has fully handled COW 781 * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs 782 * fsync() to complete (for synchronous page faults 783 * in DAX) 784 * @VM_FAULT_HINDEX_MASK: mask HINDEX value 785 * 786 */ 787 enum vm_fault_reason { 788 VM_FAULT_OOM = (__force vm_fault_t)0x000001, 789 VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, 790 VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, 791 VM_FAULT_WRITE = (__force vm_fault_t)0x000008, 792 VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, 793 VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, 794 VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, 795 VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, 796 VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, 797 VM_FAULT_RETRY = (__force vm_fault_t)0x000400, 798 VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, 799 VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, 800 VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, 801 VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, 802 }; 803 804 /* Encode hstate index for a hwpoisoned large page */ 805 #define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) 806 #define VM_FAULT_GET_HINDEX(x) (((__force unsigned int)(x) >> 16) & 0xf) 807 808 #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ 809 VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ 810 VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) 811 812 #define VM_FAULT_RESULT_TRACE \ 813 { VM_FAULT_OOM, "OOM" }, \ 814 { VM_FAULT_SIGBUS, "SIGBUS" }, \ 815 { VM_FAULT_MAJOR, "MAJOR" }, \ 816 { VM_FAULT_WRITE, "WRITE" }, \ 817 { VM_FAULT_HWPOISON, "HWPOISON" }, \ 818 { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ 819 { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ 820 { VM_FAULT_NOPAGE, "NOPAGE" }, \ 821 { VM_FAULT_LOCKED, "LOCKED" }, \ 822 { VM_FAULT_RETRY, "RETRY" }, \ 823 { VM_FAULT_FALLBACK, "FALLBACK" }, \ 824 { VM_FAULT_DONE_COW, "DONE_COW" }, \ 825 { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } 826 827 struct vm_special_mapping { 828 const char *name; /* The name, e.g. "[vdso]". */ 829 830 /* 831 * If .fault is not provided, this points to a 832 * NULL-terminated array of pages that back the special mapping. 833 * 834 * This must not be NULL unless .fault is provided. 835 */ 836 struct page **pages; 837 838 /* 839 * If non-NULL, then this is called to resolve page faults 840 * on the special mapping. If used, .pages is not checked. 841 */ 842 vm_fault_t (*fault)(const struct vm_special_mapping *sm, 843 struct vm_area_struct *vma, 844 struct vm_fault *vmf); 845 846 int (*mremap)(const struct vm_special_mapping *sm, 847 struct vm_area_struct *new_vma); 848 }; 849 850 enum tlb_flush_reason { 851 TLB_FLUSH_ON_TASK_SWITCH, 852 TLB_REMOTE_SHOOTDOWN, 853 TLB_LOCAL_SHOOTDOWN, 854 TLB_LOCAL_MM_SHOOTDOWN, 855 TLB_REMOTE_SEND_IPI, 856 NR_TLB_FLUSH_REASONS, 857 }; 858 859 /* 860 * A swap entry has to fit into a "unsigned long", as the entry is hidden 861 * in the "index" field of the swapper address space. 862 */ 863 typedef struct { 864 unsigned long val; 865 } swp_entry_t; 866 867 #endif /* _LINUX_MM_TYPES_H */ 868