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