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