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
23struct address_space;
24struct 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
31typedef void compound_page_dtor(struct page *);
32
33/*
34 * Each physical page in the system has a struct page associated with
35 * it to keep track of whatever it is we are using the page for at the
36 * moment. Note that we have no way to track which tasks are using
37 * a page, though if it is a pagecache page, rmap structures can tell us
38 * who is mapping it.
39 *
40 * The objects in struct page are organized in double word blocks in
41 * order to allows us to use atomic double word operations on portions
42 * of struct page. That is currently only used by slub but the arrangement
43 * allows the use of atomic double word operations on the flags/mapping
44 * and lru list pointers also.
45 */
46struct page {
47	/* First double word block */
48	unsigned long flags;		/* Atomic flags, some possibly
49					 * updated asynchronously */
50	union {
51		struct address_space *mapping;	/* If low bit clear, points to
52						 * inode address_space, or NULL.
53						 * If page mapped as anonymous
54						 * memory, low bit is set, and
55						 * it points to anon_vma object:
56						 * see PAGE_MAPPING_ANON below.
57						 */
58		void *s_mem;			/* slab first object */
59	};
60
61	/* Second double word */
62	struct {
63		union {
64			pgoff_t index;		/* Our offset within mapping. */
65			void *freelist;		/* sl[aou]b first free object */
66		};
67
68		union {
69#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
70	defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
71			/* Used for cmpxchg_double in slub */
72			unsigned long counters;
73#else
74			/*
75			 * Keep _count separate from slub cmpxchg_double data.
76			 * As the rest of the double word is protected by
77			 * slab_lock but _count is not.
78			 */
79			unsigned counters;
80#endif
81
82			struct {
83
84				union {
85					/*
86					 * Count of ptes mapped in
87					 * mms, to show when page is
88					 * mapped & limit reverse map
89					 * searches.
90					 *
91					 * Used also for tail pages
92					 * refcounting instead of
93					 * _count. Tail pages cannot
94					 * be mapped and keeping the
95					 * tail page _count zero at
96					 * all times guarantees
97					 * get_page_unless_zero() will
98					 * never succeed on tail
99					 * pages.
100					 */
101					atomic_t _mapcount;
102
103					struct { /* SLUB */
104						unsigned inuse:16;
105						unsigned objects:15;
106						unsigned frozen:1;
107					};
108					int units;	/* SLOB */
109				};
110				atomic_t _count;		/* Usage count, see below. */
111			};
112			unsigned int active;	/* SLAB */
113		};
114	};
115
116	/* Third double word block */
117	union {
118		struct list_head lru;	/* Pageout list, eg. active_list
119					 * protected by zone->lru_lock !
120					 * Can be used as a generic list
121					 * by the page owner.
122					 */
123		struct {		/* slub per cpu partial pages */
124			struct page *next;	/* Next partial slab */
125#ifdef CONFIG_64BIT
126			int pages;	/* Nr of partial slabs left */
127			int pobjects;	/* Approximate # of objects */
128#else
129			short int pages;
130			short int pobjects;
131#endif
132		};
133
134		struct slab *slab_page; /* slab fields */
135		struct rcu_head rcu_head;	/* Used by SLAB
136						 * when destroying via RCU
137						 */
138		/* First tail page of compound page */
139		struct {
140			compound_page_dtor *compound_dtor;
141			unsigned long compound_order;
142		};
143
144#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
145		pgtable_t pmd_huge_pte; /* protected by page->ptl */
146#endif
147	};
148
149	/* Remainder is not double word aligned */
150	union {
151		unsigned long private;		/* Mapping-private opaque data:
152					 	 * usually used for buffer_heads
153						 * if PagePrivate set; used for
154						 * swp_entry_t if PageSwapCache;
155						 * indicates order in the buddy
156						 * system if PG_buddy is set.
157						 */
158#if USE_SPLIT_PTE_PTLOCKS
159#if ALLOC_SPLIT_PTLOCKS
160		spinlock_t *ptl;
161#else
162		spinlock_t ptl;
163#endif
164#endif
165		struct kmem_cache *slab_cache;	/* SL[AU]B: Pointer to slab */
166		struct page *first_page;	/* Compound tail pages */
167	};
168
169#ifdef CONFIG_MEMCG
170	struct mem_cgroup *mem_cgroup;
171#endif
172
173	/*
174	 * On machines where all RAM is mapped into kernel address space,
175	 * we can simply calculate the virtual address. On machines with
176	 * highmem some memory is mapped into kernel virtual memory
177	 * dynamically, so we need a place to store that address.
178	 * Note that this field could be 16 bits on x86 ... ;)
179	 *
180	 * Architectures with slow multiplication can define
181	 * WANT_PAGE_VIRTUAL in asm/page.h
182	 */
183#if defined(WANT_PAGE_VIRTUAL)
184	void *virtual;			/* Kernel virtual address (NULL if
185					   not kmapped, ie. highmem) */
186#endif /* WANT_PAGE_VIRTUAL */
187
188#ifdef CONFIG_KMEMCHECK
189	/*
190	 * kmemcheck wants to track the status of each byte in a page; this
191	 * is a pointer to such a status block. NULL if not tracked.
192	 */
193	void *shadow;
194#endif
195
196#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
197	int _last_cpupid;
198#endif
199}
200/*
201 * The struct page can be forced to be double word aligned so that atomic ops
202 * on double words work. The SLUB allocator can make use of such a feature.
203 */
204#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
205	__aligned(2 * sizeof(unsigned long))
206#endif
207;
208
209struct page_frag {
210	struct page *page;
211#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
212	__u32 offset;
213	__u32 size;
214#else
215	__u16 offset;
216	__u16 size;
217#endif
218};
219
220typedef unsigned long __nocast vm_flags_t;
221
222/*
223 * A region containing a mapping of a non-memory backed file under NOMMU
224 * conditions.  These are held in a global tree and are pinned by the VMAs that
225 * map parts of them.
226 */
227struct vm_region {
228	struct rb_node	vm_rb;		/* link in global region tree */
229	vm_flags_t	vm_flags;	/* VMA vm_flags */
230	unsigned long	vm_start;	/* start address of region */
231	unsigned long	vm_end;		/* region initialised to here */
232	unsigned long	vm_top;		/* region allocated to here */
233	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
234	struct file	*vm_file;	/* the backing file or NULL */
235
236	int		vm_usage;	/* region usage count (access under nommu_region_sem) */
237	bool		vm_icache_flushed : 1; /* true if the icache has been flushed for
238						* this region */
239};
240
241/*
242 * This struct defines a memory VMM memory area. There is one of these
243 * per VM-area/task.  A VM area is any part of the process virtual memory
244 * space that has a special rule for the page-fault handlers (ie a shared
245 * library, the executable area etc).
246 */
247struct vm_area_struct {
248	/* The first cache line has the info for VMA tree walking. */
249
250	unsigned long vm_start;		/* Our start address within vm_mm. */
251	unsigned long vm_end;		/* The first byte after our end address
252					   within vm_mm. */
253
254	/* linked list of VM areas per task, sorted by address */
255	struct vm_area_struct *vm_next, *vm_prev;
256
257	struct rb_node vm_rb;
258
259	/*
260	 * Largest free memory gap in bytes to the left of this VMA.
261	 * Either between this VMA and vma->vm_prev, or between one of the
262	 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
263	 * get_unmapped_area find a free area of the right size.
264	 */
265	unsigned long rb_subtree_gap;
266
267	/* Second cache line starts here. */
268
269	struct mm_struct *vm_mm;	/* The address space we belong to. */
270	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
271	unsigned long vm_flags;		/* Flags, see mm.h. */
272
273	/*
274	 * For areas with an address space and backing store,
275	 * linkage into the address_space->i_mmap interval tree.
276	 */
277	struct {
278		struct rb_node rb;
279		unsigned long rb_subtree_last;
280	} shared;
281
282	/*
283	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
284	 * list, after a COW of one of the file pages.	A MAP_SHARED vma
285	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
286	 * or brk vma (with NULL file) can only be in an anon_vma list.
287	 */
288	struct list_head anon_vma_chain; /* Serialized by mmap_sem &
289					  * page_table_lock */
290	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */
291
292	/* Function pointers to deal with this struct. */
293	const struct vm_operations_struct *vm_ops;
294
295	/* Information about our backing store: */
296	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
297					   units, *not* PAGE_CACHE_SIZE */
298	struct file * vm_file;		/* File we map to (can be NULL). */
299	void * vm_private_data;		/* was vm_pte (shared mem) */
300
301#ifndef CONFIG_MMU
302	struct vm_region *vm_region;	/* NOMMU mapping region */
303#endif
304#ifdef CONFIG_NUMA
305	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
306#endif
307};
308
309struct core_thread {
310	struct task_struct *task;
311	struct core_thread *next;
312};
313
314struct core_state {
315	atomic_t nr_threads;
316	struct core_thread dumper;
317	struct completion startup;
318};
319
320enum {
321	MM_FILEPAGES,
322	MM_ANONPAGES,
323	MM_SWAPENTS,
324	NR_MM_COUNTERS
325};
326
327#if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
328#define SPLIT_RSS_COUNTING
329/* per-thread cached information, */
330struct task_rss_stat {
331	int events;	/* for synchronization threshold */
332	int count[NR_MM_COUNTERS];
333};
334#endif /* USE_SPLIT_PTE_PTLOCKS */
335
336struct mm_rss_stat {
337	atomic_long_t count[NR_MM_COUNTERS];
338};
339
340struct kioctx_table;
341struct mm_struct {
342	struct vm_area_struct *mmap;		/* list of VMAs */
343	struct rb_root mm_rb;
344	u32 vmacache_seqnum;                   /* per-thread vmacache */
345#ifdef CONFIG_MMU
346	unsigned long (*get_unmapped_area) (struct file *filp,
347				unsigned long addr, unsigned long len,
348				unsigned long pgoff, unsigned long flags);
349#endif
350	unsigned long mmap_base;		/* base of mmap area */
351	unsigned long mmap_legacy_base;         /* base of mmap area in bottom-up allocations */
352	unsigned long task_size;		/* size of task vm space */
353	unsigned long highest_vm_end;		/* highest vma end address */
354	pgd_t * pgd;
355	atomic_t mm_users;			/* How many users with user space? */
356	atomic_t mm_count;			/* How many references to "struct mm_struct" (users count as 1) */
357	atomic_long_t nr_ptes;			/* PTE page table pages */
358#if CONFIG_PGTABLE_LEVELS > 2
359	atomic_long_t nr_pmds;			/* PMD page table pages */
360#endif
361	int map_count;				/* number of VMAs */
362
363	spinlock_t page_table_lock;		/* Protects page tables and some counters */
364	struct rw_semaphore mmap_sem;
365
366	struct list_head mmlist;		/* List of maybe swapped mm's.	These are globally strung
367						 * together off init_mm.mmlist, and are protected
368						 * by mmlist_lock
369						 */
370
371
372	unsigned long hiwater_rss;	/* High-watermark of RSS usage */
373	unsigned long hiwater_vm;	/* High-water virtual memory usage */
374
375	unsigned long total_vm;		/* Total pages mapped */
376	unsigned long locked_vm;	/* Pages that have PG_mlocked set */
377	unsigned long pinned_vm;	/* Refcount permanently increased */
378	unsigned long shared_vm;	/* Shared pages (files) */
379	unsigned long exec_vm;		/* VM_EXEC & ~VM_WRITE */
380	unsigned long stack_vm;		/* VM_GROWSUP/DOWN */
381	unsigned long def_flags;
382	unsigned long start_code, end_code, start_data, end_data;
383	unsigned long start_brk, brk, start_stack;
384	unsigned long arg_start, arg_end, env_start, env_end;
385
386	unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
387
388	/*
389	 * Special counters, in some configurations protected by the
390	 * page_table_lock, in other configurations by being atomic.
391	 */
392	struct mm_rss_stat rss_stat;
393
394	struct linux_binfmt *binfmt;
395
396	cpumask_var_t cpu_vm_mask_var;
397
398	/* Architecture-specific MM context */
399	mm_context_t context;
400
401	unsigned long flags; /* Must use atomic bitops to access the bits */
402
403	struct core_state *core_state; /* coredumping support */
404#ifdef CONFIG_AIO
405	spinlock_t			ioctx_lock;
406	struct kioctx_table __rcu	*ioctx_table;
407#endif
408#ifdef CONFIG_MEMCG
409	/*
410	 * "owner" points to a task that is regarded as the canonical
411	 * user/owner of this mm. All of the following must be true in
412	 * order for it to be changed:
413	 *
414	 * current == mm->owner
415	 * current->mm != mm
416	 * new_owner->mm == mm
417	 * new_owner->alloc_lock is held
418	 */
419	struct task_struct __rcu *owner;
420#endif
421
422	/* store ref to file /proc/<pid>/exe symlink points to */
423	struct file __rcu *exe_file;
424#ifdef CONFIG_MMU_NOTIFIER
425	struct mmu_notifier_mm *mmu_notifier_mm;
426#endif
427#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
428	pgtable_t pmd_huge_pte; /* protected by page_table_lock */
429#endif
430#ifdef CONFIG_CPUMASK_OFFSTACK
431	struct cpumask cpumask_allocation;
432#endif
433#ifdef CONFIG_NUMA_BALANCING
434	/*
435	 * numa_next_scan is the next time that the PTEs will be marked
436	 * pte_numa. NUMA hinting faults will gather statistics and migrate
437	 * pages to new nodes if necessary.
438	 */
439	unsigned long numa_next_scan;
440
441	/* Restart point for scanning and setting pte_numa */
442	unsigned long numa_scan_offset;
443
444	/* numa_scan_seq prevents two threads setting pte_numa */
445	int numa_scan_seq;
446#endif
447#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
448	/*
449	 * An operation with batched TLB flushing is going on. Anything that
450	 * can move process memory needs to flush the TLB when moving a
451	 * PROT_NONE or PROT_NUMA mapped page.
452	 */
453	bool tlb_flush_pending;
454#endif
455	struct uprobes_state uprobes_state;
456#ifdef CONFIG_X86_INTEL_MPX
457	/* address of the bounds directory */
458	void __user *bd_addr;
459#endif
460};
461
462static inline void mm_init_cpumask(struct mm_struct *mm)
463{
464#ifdef CONFIG_CPUMASK_OFFSTACK
465	mm->cpu_vm_mask_var = &mm->cpumask_allocation;
466#endif
467	cpumask_clear(mm->cpu_vm_mask_var);
468}
469
470/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
471static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
472{
473	return mm->cpu_vm_mask_var;
474}
475
476#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
477/*
478 * Memory barriers to keep this state in sync are graciously provided by
479 * the page table locks, outside of which no page table modifications happen.
480 * The barriers below prevent the compiler from re-ordering the instructions
481 * around the memory barriers that are already present in the code.
482 */
483static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
484{
485	barrier();
486	return mm->tlb_flush_pending;
487}
488static inline void set_tlb_flush_pending(struct mm_struct *mm)
489{
490	mm->tlb_flush_pending = true;
491
492	/*
493	 * Guarantee that the tlb_flush_pending store does not leak into the
494	 * critical section updating the page tables
495	 */
496	smp_mb__before_spinlock();
497}
498/* Clearing is done after a TLB flush, which also provides a barrier. */
499static inline void clear_tlb_flush_pending(struct mm_struct *mm)
500{
501	barrier();
502	mm->tlb_flush_pending = false;
503}
504#else
505static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
506{
507	return false;
508}
509static inline void set_tlb_flush_pending(struct mm_struct *mm)
510{
511}
512static inline void clear_tlb_flush_pending(struct mm_struct *mm)
513{
514}
515#endif
516
517struct vm_special_mapping
518{
519	const char *name;
520	struct page **pages;
521};
522
523enum tlb_flush_reason {
524	TLB_FLUSH_ON_TASK_SWITCH,
525	TLB_REMOTE_SHOOTDOWN,
526	TLB_LOCAL_SHOOTDOWN,
527	TLB_LOCAL_MM_SHOOTDOWN,
528	NR_TLB_FLUSH_REASONS,
529};
530
531 /*
532  * A swap entry has to fit into a "unsigned long", as the entry is hidden
533  * in the "index" field of the swapper address space.
534  */
535typedef struct {
536	unsigned long val;
537} swp_entry_t;
538
539#endif /* _LINUX_MM_TYPES_H */
540