1 #ifndef _LINUX_MM_TYPES_H 2 #define _LINUX_MM_TYPES_H 3 4 #include <linux/auxvec.h> 5 #include <linux/types.h> 6 #include <linux/threads.h> 7 #include <linux/list.h> 8 #include <linux/spinlock.h> 9 #include <linux/rbtree.h> 10 #include <linux/rwsem.h> 11 #include <linux/completion.h> 12 #include <linux/cpumask.h> 13 #include <linux/uprobes.h> 14 #include <linux/page-flags-layout.h> 15 #include <linux/workqueue.h> 16 #include <asm/page.h> 17 #include <asm/mmu.h> 18 19 #ifndef AT_VECTOR_SIZE_ARCH 20 #define AT_VECTOR_SIZE_ARCH 0 21 #endif 22 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) 23 24 struct address_space; 25 struct mem_cgroup; 26 27 #define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS) 28 #define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \ 29 IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK)) 30 #define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8) 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 * The objects in struct page are organized in double word blocks in 40 * order to allows us to use atomic double word operations on portions 41 * of struct page. That is currently only used by slub but the arrangement 42 * allows the use of atomic double word operations on the flags/mapping 43 * and lru list pointers also. 44 */ 45 struct page { 46 /* First double word block */ 47 unsigned long flags; /* Atomic flags, some possibly 48 * updated asynchronously */ 49 union { 50 struct address_space *mapping; /* If low bit clear, points to 51 * inode address_space, or NULL. 52 * If page mapped as anonymous 53 * memory, low bit is set, and 54 * it points to anon_vma object: 55 * see PAGE_MAPPING_ANON below. 56 */ 57 void *s_mem; /* slab first object */ 58 atomic_t compound_mapcount; /* first tail page */ 59 /* page_deferred_list().next -- second tail page */ 60 }; 61 62 /* Second double word */ 63 struct { 64 union { 65 pgoff_t index; /* Our offset within mapping. */ 66 void *freelist; /* sl[aou]b first free object */ 67 /* page_deferred_list().prev -- second tail page */ 68 }; 69 70 union { 71 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ 72 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 73 /* Used for cmpxchg_double in slub */ 74 unsigned long counters; 75 #else 76 /* 77 * Keep _refcount separate from slub cmpxchg_double 78 * data. As the rest of the double word is protected by 79 * slab_lock but _refcount is not. 80 */ 81 unsigned counters; 82 #endif 83 84 struct { 85 86 union { 87 /* 88 * Count of ptes mapped in mms, to show 89 * when page is mapped & limit reverse 90 * map searches. 91 */ 92 atomic_t _mapcount; 93 94 struct { /* SLUB */ 95 unsigned inuse:16; 96 unsigned objects:15; 97 unsigned frozen:1; 98 }; 99 int units; /* SLOB */ 100 }; 101 /* 102 * Usage count, *USE WRAPPER FUNCTION* 103 * when manual accounting. See page_ref.h 104 */ 105 atomic_t _refcount; 106 }; 107 unsigned int active; /* SLAB */ 108 }; 109 }; 110 111 /* 112 * Third double word block 113 * 114 * WARNING: bit 0 of the first word encode PageTail(). That means 115 * the rest users of the storage space MUST NOT use the bit to 116 * avoid collision and false-positive PageTail(). 117 */ 118 union { 119 struct list_head lru; /* Pageout list, eg. active_list 120 * protected by zone->lru_lock ! 121 * Can be used as a generic list 122 * by the page owner. 123 */ 124 struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an 125 * lru or handled by a slab 126 * allocator, this points to the 127 * hosting device page map. 128 */ 129 struct { /* slub per cpu partial pages */ 130 struct page *next; /* Next partial slab */ 131 #ifdef CONFIG_64BIT 132 int pages; /* Nr of partial slabs left */ 133 int pobjects; /* Approximate # of objects */ 134 #else 135 short int pages; 136 short int pobjects; 137 #endif 138 }; 139 140 struct rcu_head rcu_head; /* Used by SLAB 141 * when destroying via RCU 142 */ 143 /* Tail pages of compound page */ 144 struct { 145 unsigned long compound_head; /* If bit zero is set */ 146 147 /* First tail page only */ 148 #ifdef CONFIG_64BIT 149 /* 150 * On 64 bit system we have enough space in struct page 151 * to encode compound_dtor and compound_order with 152 * unsigned int. It can help compiler generate better or 153 * smaller code on some archtectures. 154 */ 155 unsigned int compound_dtor; 156 unsigned int compound_order; 157 #else 158 unsigned short int compound_dtor; 159 unsigned short int compound_order; 160 #endif 161 }; 162 163 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS 164 struct { 165 unsigned long __pad; /* do not overlay pmd_huge_pte 166 * with compound_head to avoid 167 * possible bit 0 collision. 168 */ 169 pgtable_t pmd_huge_pte; /* protected by page->ptl */ 170 }; 171 #endif 172 }; 173 174 /* Remainder is not double word aligned */ 175 union { 176 unsigned long private; /* Mapping-private opaque data: 177 * usually used for buffer_heads 178 * if PagePrivate set; used for 179 * swp_entry_t if PageSwapCache; 180 * indicates order in the buddy 181 * system if PG_buddy is set. 182 */ 183 #if USE_SPLIT_PTE_PTLOCKS 184 #if ALLOC_SPLIT_PTLOCKS 185 spinlock_t *ptl; 186 #else 187 spinlock_t ptl; 188 #endif 189 #endif 190 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */ 191 }; 192 193 #ifdef CONFIG_MEMCG 194 struct mem_cgroup *mem_cgroup; 195 #endif 196 197 /* 198 * On machines where all RAM is mapped into kernel address space, 199 * we can simply calculate the virtual address. On machines with 200 * highmem some memory is mapped into kernel virtual memory 201 * dynamically, so we need a place to store that address. 202 * Note that this field could be 16 bits on x86 ... ;) 203 * 204 * Architectures with slow multiplication can define 205 * WANT_PAGE_VIRTUAL in asm/page.h 206 */ 207 #if defined(WANT_PAGE_VIRTUAL) 208 void *virtual; /* Kernel virtual address (NULL if 209 not kmapped, ie. highmem) */ 210 #endif /* WANT_PAGE_VIRTUAL */ 211 212 #ifdef CONFIG_KMEMCHECK 213 /* 214 * kmemcheck wants to track the status of each byte in a page; this 215 * is a pointer to such a status block. NULL if not tracked. 216 */ 217 void *shadow; 218 #endif 219 220 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS 221 int _last_cpupid; 222 #endif 223 } 224 /* 225 * The struct page can be forced to be double word aligned so that atomic ops 226 * on double words work. The SLUB allocator can make use of such a feature. 227 */ 228 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE 229 __aligned(2 * sizeof(unsigned long)) 230 #endif 231 ; 232 233 struct page_frag { 234 struct page *page; 235 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536) 236 __u32 offset; 237 __u32 size; 238 #else 239 __u16 offset; 240 __u16 size; 241 #endif 242 }; 243 244 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) 245 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) 246 247 struct page_frag_cache { 248 void * va; 249 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) 250 __u16 offset; 251 __u16 size; 252 #else 253 __u32 offset; 254 #endif 255 /* we maintain a pagecount bias, so that we dont dirty cache line 256 * containing page->_refcount every time we allocate a fragment. 257 */ 258 unsigned int pagecnt_bias; 259 bool pfmemalloc; 260 }; 261 262 typedef unsigned long vm_flags_t; 263 264 /* 265 * A region containing a mapping of a non-memory backed file under NOMMU 266 * conditions. These are held in a global tree and are pinned by the VMAs that 267 * map parts of them. 268 */ 269 struct vm_region { 270 struct rb_node vm_rb; /* link in global region tree */ 271 vm_flags_t vm_flags; /* VMA vm_flags */ 272 unsigned long vm_start; /* start address of region */ 273 unsigned long vm_end; /* region initialised to here */ 274 unsigned long vm_top; /* region allocated to here */ 275 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ 276 struct file *vm_file; /* the backing file or NULL */ 277 278 int vm_usage; /* region usage count (access under nommu_region_sem) */ 279 bool vm_icache_flushed : 1; /* true if the icache has been flushed for 280 * this region */ 281 }; 282 283 #ifdef CONFIG_USERFAULTFD 284 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) 285 struct vm_userfaultfd_ctx { 286 struct userfaultfd_ctx *ctx; 287 }; 288 #else /* CONFIG_USERFAULTFD */ 289 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) 290 struct vm_userfaultfd_ctx {}; 291 #endif /* CONFIG_USERFAULTFD */ 292 293 /* 294 * This struct defines a memory VMM memory area. There is one of these 295 * per VM-area/task. A VM area is any part of the process virtual memory 296 * space that has a special rule for the page-fault handlers (ie a shared 297 * library, the executable area etc). 298 */ 299 struct vm_area_struct { 300 /* The first cache line has the info for VMA tree walking. */ 301 302 unsigned long vm_start; /* Our start address within vm_mm. */ 303 unsigned long vm_end; /* The first byte after our end address 304 within vm_mm. */ 305 306 /* linked list of VM areas per task, sorted by address */ 307 struct vm_area_struct *vm_next, *vm_prev; 308 309 struct rb_node vm_rb; 310 311 /* 312 * Largest free memory gap in bytes to the left of this VMA. 313 * Either between this VMA and vma->vm_prev, or between one of the 314 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps 315 * get_unmapped_area find a free area of the right size. 316 */ 317 unsigned long rb_subtree_gap; 318 319 /* Second cache line starts here. */ 320 321 struct mm_struct *vm_mm; /* The address space we belong to. */ 322 pgprot_t vm_page_prot; /* Access permissions of this VMA. */ 323 unsigned long vm_flags; /* Flags, see mm.h. */ 324 325 /* 326 * For areas with an address space and backing store, 327 * linkage into the address_space->i_mmap interval tree. 328 */ 329 struct { 330 struct rb_node rb; 331 unsigned long rb_subtree_last; 332 } shared; 333 334 /* 335 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma 336 * list, after a COW of one of the file pages. A MAP_SHARED vma 337 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack 338 * or brk vma (with NULL file) can only be in an anon_vma list. 339 */ 340 struct list_head anon_vma_chain; /* Serialized by mmap_sem & 341 * page_table_lock */ 342 struct anon_vma *anon_vma; /* Serialized by page_table_lock */ 343 344 /* Function pointers to deal with this struct. */ 345 const struct vm_operations_struct *vm_ops; 346 347 /* Information about our backing store: */ 348 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE 349 units */ 350 struct file * vm_file; /* File we map to (can be NULL). */ 351 void * vm_private_data; /* was vm_pte (shared mem) */ 352 353 #ifndef CONFIG_MMU 354 struct vm_region *vm_region; /* NOMMU mapping region */ 355 #endif 356 #ifdef CONFIG_NUMA 357 struct mempolicy *vm_policy; /* NUMA policy for the VMA */ 358 #endif 359 struct vm_userfaultfd_ctx vm_userfaultfd_ctx; 360 }; 361 362 struct core_thread { 363 struct task_struct *task; 364 struct core_thread *next; 365 }; 366 367 struct core_state { 368 atomic_t nr_threads; 369 struct core_thread dumper; 370 struct completion startup; 371 }; 372 373 enum { 374 MM_FILEPAGES, /* Resident file mapping pages */ 375 MM_ANONPAGES, /* Resident anonymous pages */ 376 MM_SWAPENTS, /* Anonymous swap entries */ 377 MM_SHMEMPAGES, /* Resident shared memory pages */ 378 NR_MM_COUNTERS 379 }; 380 381 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU) 382 #define SPLIT_RSS_COUNTING 383 /* per-thread cached information, */ 384 struct task_rss_stat { 385 int events; /* for synchronization threshold */ 386 int count[NR_MM_COUNTERS]; 387 }; 388 #endif /* USE_SPLIT_PTE_PTLOCKS */ 389 390 struct mm_rss_stat { 391 atomic_long_t count[NR_MM_COUNTERS]; 392 }; 393 394 struct kioctx_table; 395 struct mm_struct { 396 struct vm_area_struct *mmap; /* list of VMAs */ 397 struct rb_root mm_rb; 398 u32 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 unsigned long task_size; /* size of task vm space */ 407 unsigned long highest_vm_end; /* highest vma end address */ 408 pgd_t * pgd; 409 atomic_t mm_users; /* How many users with user space? */ 410 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ 411 atomic_long_t nr_ptes; /* PTE page table pages */ 412 #if CONFIG_PGTABLE_LEVELS > 2 413 atomic_long_t nr_pmds; /* PMD page table pages */ 414 #endif 415 int map_count; /* number of VMAs */ 416 417 spinlock_t page_table_lock; /* Protects page tables and some counters */ 418 struct rw_semaphore mmap_sem; 419 420 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung 421 * together off init_mm.mmlist, and are protected 422 * by mmlist_lock 423 */ 424 425 426 unsigned long hiwater_rss; /* High-watermark of RSS usage */ 427 unsigned long hiwater_vm; /* High-water virtual memory usage */ 428 429 unsigned long total_vm; /* Total pages mapped */ 430 unsigned long locked_vm; /* Pages that have PG_mlocked set */ 431 unsigned long pinned_vm; /* Refcount permanently increased */ 432 unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ 433 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ 434 unsigned long stack_vm; /* VM_STACK */ 435 unsigned long def_flags; 436 unsigned long start_code, end_code, start_data, end_data; 437 unsigned long start_brk, brk, start_stack; 438 unsigned long arg_start, arg_end, env_start, env_end; 439 440 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ 441 442 /* 443 * Special counters, in some configurations protected by the 444 * page_table_lock, in other configurations by being atomic. 445 */ 446 struct mm_rss_stat rss_stat; 447 448 struct linux_binfmt *binfmt; 449 450 cpumask_var_t cpu_vm_mask_var; 451 452 /* Architecture-specific MM context */ 453 mm_context_t context; 454 455 unsigned long flags; /* Must use atomic bitops to access the bits */ 456 457 struct core_state *core_state; /* coredumping support */ 458 #ifdef CONFIG_AIO 459 spinlock_t ioctx_lock; 460 struct kioctx_table __rcu *ioctx_table; 461 #endif 462 #ifdef CONFIG_MEMCG 463 /* 464 * "owner" points to a task that is regarded as the canonical 465 * user/owner of this mm. All of the following must be true in 466 * order for it to be changed: 467 * 468 * current == mm->owner 469 * current->mm != mm 470 * new_owner->mm == mm 471 * new_owner->alloc_lock is held 472 */ 473 struct task_struct __rcu *owner; 474 #endif 475 476 /* store ref to file /proc/<pid>/exe symlink points to */ 477 struct file __rcu *exe_file; 478 #ifdef CONFIG_MMU_NOTIFIER 479 struct mmu_notifier_mm *mmu_notifier_mm; 480 #endif 481 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS 482 pgtable_t pmd_huge_pte; /* protected by page_table_lock */ 483 #endif 484 #ifdef CONFIG_CPUMASK_OFFSTACK 485 struct cpumask cpumask_allocation; 486 #endif 487 #ifdef CONFIG_NUMA_BALANCING 488 /* 489 * numa_next_scan is the next time that the PTEs will be marked 490 * pte_numa. NUMA hinting faults will gather statistics and migrate 491 * pages to new nodes if necessary. 492 */ 493 unsigned long numa_next_scan; 494 495 /* Restart point for scanning and setting pte_numa */ 496 unsigned long numa_scan_offset; 497 498 /* numa_scan_seq prevents two threads setting pte_numa */ 499 int numa_scan_seq; 500 #endif 501 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION) 502 /* 503 * An operation with batched TLB flushing is going on. Anything that 504 * can move process memory needs to flush the TLB when moving a 505 * PROT_NONE or PROT_NUMA mapped page. 506 */ 507 bool tlb_flush_pending; 508 #endif 509 struct uprobes_state uprobes_state; 510 #ifdef CONFIG_X86_INTEL_MPX 511 /* address of the bounds directory */ 512 void __user *bd_addr; 513 #endif 514 #ifdef CONFIG_HUGETLB_PAGE 515 atomic_long_t hugetlb_usage; 516 #endif 517 #ifdef CONFIG_MMU 518 struct work_struct async_put_work; 519 #endif 520 }; 521 522 static inline void mm_init_cpumask(struct mm_struct *mm) 523 { 524 #ifdef CONFIG_CPUMASK_OFFSTACK 525 mm->cpu_vm_mask_var = &mm->cpumask_allocation; 526 #endif 527 cpumask_clear(mm->cpu_vm_mask_var); 528 } 529 530 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ 531 static inline cpumask_t *mm_cpumask(struct mm_struct *mm) 532 { 533 return mm->cpu_vm_mask_var; 534 } 535 536 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION) 537 /* 538 * Memory barriers to keep this state in sync are graciously provided by 539 * the page table locks, outside of which no page table modifications happen. 540 * The barriers below prevent the compiler from re-ordering the instructions 541 * around the memory barriers that are already present in the code. 542 */ 543 static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 544 { 545 barrier(); 546 return mm->tlb_flush_pending; 547 } 548 static inline void set_tlb_flush_pending(struct mm_struct *mm) 549 { 550 mm->tlb_flush_pending = true; 551 552 /* 553 * Guarantee that the tlb_flush_pending store does not leak into the 554 * critical section updating the page tables 555 */ 556 smp_mb__before_spinlock(); 557 } 558 /* Clearing is done after a TLB flush, which also provides a barrier. */ 559 static inline void clear_tlb_flush_pending(struct mm_struct *mm) 560 { 561 barrier(); 562 mm->tlb_flush_pending = false; 563 } 564 #else 565 static inline bool mm_tlb_flush_pending(struct mm_struct *mm) 566 { 567 return false; 568 } 569 static inline void set_tlb_flush_pending(struct mm_struct *mm) 570 { 571 } 572 static inline void clear_tlb_flush_pending(struct mm_struct *mm) 573 { 574 } 575 #endif 576 577 struct vm_fault; 578 579 struct vm_special_mapping { 580 const char *name; /* The name, e.g. "[vdso]". */ 581 582 /* 583 * If .fault is not provided, this points to a 584 * NULL-terminated array of pages that back the special mapping. 585 * 586 * This must not be NULL unless .fault is provided. 587 */ 588 struct page **pages; 589 590 /* 591 * If non-NULL, then this is called to resolve page faults 592 * on the special mapping. If used, .pages is not checked. 593 */ 594 int (*fault)(const struct vm_special_mapping *sm, 595 struct vm_area_struct *vma, 596 struct vm_fault *vmf); 597 }; 598 599 enum tlb_flush_reason { 600 TLB_FLUSH_ON_TASK_SWITCH, 601 TLB_REMOTE_SHOOTDOWN, 602 TLB_LOCAL_SHOOTDOWN, 603 TLB_LOCAL_MM_SHOOTDOWN, 604 TLB_REMOTE_SEND_IPI, 605 NR_TLB_FLUSH_REASONS, 606 }; 607 608 /* 609 * A swap entry has to fit into a "unsigned long", as the entry is hidden 610 * in the "index" field of the swapper address space. 611 */ 612 typedef struct { 613 unsigned long val; 614 } swp_entry_t; 615 616 #endif /* _LINUX_MM_TYPES_H */ 617