/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_MM_TYPES_H #define _LINUX_MM_TYPES_H #include #include #include #include #include #include #include #include #include #include #include #include #ifndef AT_VECTOR_SIZE_ARCH #define AT_VECTOR_SIZE_ARCH 0 #endif #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) struct address_space; struct mem_cgroup; struct hmm; /* * Each physical page in the system has a struct page associated with * it to keep track of whatever it is we are using the page for at the * moment. Note that we have no way to track which tasks are using * a page, though if it is a pagecache page, rmap structures can tell us * who is mapping it. * * The objects in struct page are organized in double word blocks in * order to allows us to use atomic double word operations on portions * of struct page. That is currently only used by slub but the arrangement * allows the use of atomic double word operations on the flags/mapping * and lru list pointers also. */ struct page { /* First double word block */ unsigned long flags; /* Atomic flags, some possibly * updated asynchronously */ union { struct address_space *mapping; /* If low bit clear, points to * inode address_space, or NULL. * If page mapped as anonymous * memory, low bit is set, and * it points to anon_vma object: * see PAGE_MAPPING_ANON below. */ void *s_mem; /* slab first object */ atomic_t compound_mapcount; /* first tail page */ /* page_deferred_list().next -- second tail page */ }; /* Second double word */ union { pgoff_t index; /* Our offset within mapping. */ void *freelist; /* sl[aou]b first free object */ /* page_deferred_list().prev -- second tail page */ }; union { #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) /* Used for cmpxchg_double in slub */ unsigned long counters; #else /* * Keep _refcount separate from slub cmpxchg_double data. * As the rest of the double word is protected by slab_lock * but _refcount is not. */ unsigned counters; #endif struct { union { /* * Count of ptes mapped in mms, to show when * page is mapped & limit reverse map searches. * * Extra information about page type may be * stored here for pages that are never mapped, * in which case the value MUST BE <= -2. * See page-flags.h for more details. */ atomic_t _mapcount; unsigned int active; /* SLAB */ struct { /* SLUB */ unsigned inuse:16; unsigned objects:15; unsigned frozen:1; }; int units; /* SLOB */ }; /* * Usage count, *USE WRAPPER FUNCTION* when manual * accounting. See page_ref.h */ atomic_t _refcount; }; }; /* * Third double word block * * WARNING: bit 0 of the first word encode PageTail(). That means * the rest users of the storage space MUST NOT use the bit to * avoid collision and false-positive PageTail(). */ union { struct list_head lru; /* Pageout list, eg. active_list * protected by zone_lru_lock ! * Can be used as a generic list * by the page owner. */ struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an * lru or handled by a slab * allocator, this points to the * hosting device page map. */ struct { /* slub per cpu partial pages */ struct page *next; /* Next partial slab */ #ifdef CONFIG_64BIT int pages; /* Nr of partial slabs left */ int pobjects; /* Approximate # of objects */ #else short int pages; short int pobjects; #endif }; struct rcu_head rcu_head; /* Used by SLAB * when destroying via RCU */ /* Tail pages of compound page */ struct { unsigned long compound_head; /* If bit zero is set */ /* First tail page only */ #ifdef CONFIG_64BIT /* * On 64 bit system we have enough space in struct page * to encode compound_dtor and compound_order with * unsigned int. It can help compiler generate better or * smaller code on some archtectures. */ unsigned int compound_dtor; unsigned int compound_order; #else unsigned short int compound_dtor; unsigned short int compound_order; #endif }; #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS struct { unsigned long __pad; /* do not overlay pmd_huge_pte * with compound_head to avoid * possible bit 0 collision. */ pgtable_t pmd_huge_pte; /* protected by page->ptl */ }; #endif }; /* Remainder is not double word aligned */ union { unsigned long private; /* Mapping-private opaque data: * usually used for buffer_heads * if PagePrivate set; used for * swp_entry_t if PageSwapCache; * indicates order in the buddy * system if PG_buddy is set. */ #if USE_SPLIT_PTE_PTLOCKS #if ALLOC_SPLIT_PTLOCKS spinlock_t *ptl; #else spinlock_t ptl; #endif #endif struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */ }; #ifdef CONFIG_MEMCG struct mem_cgroup *mem_cgroup; #endif /* * On machines where all RAM is mapped into kernel address space, * we can simply calculate the virtual address. On machines with * highmem some memory is mapped into kernel virtual memory * dynamically, so we need a place to store that address. * Note that this field could be 16 bits on x86 ... ;) * * Architectures with slow multiplication can define * WANT_PAGE_VIRTUAL in asm/page.h */ #if defined(WANT_PAGE_VIRTUAL) void *virtual; /* Kernel virtual address (NULL if not kmapped, ie. highmem) */ #endif /* WANT_PAGE_VIRTUAL */ #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS int _last_cpupid; #endif } /* * The struct page can be forced to be double word aligned so that atomic ops * on double words work. The SLUB allocator can make use of such a feature. */ #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE __aligned(2 * sizeof(unsigned long)) #endif ; #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) struct page_frag_cache { void * va; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) __u16 offset; __u16 size; #else __u32 offset; #endif /* we maintain a pagecount bias, so that we dont dirty cache line * containing page->_refcount every time we allocate a fragment. */ unsigned int pagecnt_bias; bool pfmemalloc; }; typedef unsigned long vm_flags_t; static inline atomic_t *compound_mapcount_ptr(struct page *page) { return &page[1].compound_mapcount; } /* * A region containing a mapping of a non-memory backed file under NOMMU * conditions. These are held in a global tree and are pinned by the VMAs that * map parts of them. */ struct vm_region { struct rb_node vm_rb; /* link in global region tree */ vm_flags_t vm_flags; /* VMA vm_flags */ unsigned long vm_start; /* start address of region */ unsigned long vm_end; /* region initialised to here */ unsigned long vm_top; /* region allocated to here */ unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */ struct file *vm_file; /* the backing file or NULL */ int vm_usage; /* region usage count (access under nommu_region_sem) */ bool vm_icache_flushed : 1; /* true if the icache has been flushed for * this region */ }; #ifdef CONFIG_USERFAULTFD #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, }) struct vm_userfaultfd_ctx { struct userfaultfd_ctx *ctx; }; #else /* CONFIG_USERFAULTFD */ #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {}) struct vm_userfaultfd_ctx {}; #endif /* CONFIG_USERFAULTFD */ /* * This struct defines a memory VMM memory area. There is one of these * per VM-area/task. A VM area is any part of the process virtual memory * space that has a special rule for the page-fault handlers (ie a shared * library, the executable area etc). */ struct vm_area_struct { /* The first cache line has the info for VMA tree walking. */ unsigned long vm_start; /* Our start address within vm_mm. */ unsigned long vm_end; /* The first byte after our end address within vm_mm. */ /* linked list of VM areas per task, sorted by address */ struct vm_area_struct *vm_next, *vm_prev; struct rb_node vm_rb; /* * Largest free memory gap in bytes to the left of this VMA. * Either between this VMA and vma->vm_prev, or between one of the * VMAs below us in the VMA rbtree and its ->vm_prev. This helps * get_unmapped_area find a free area of the right size. */ unsigned long rb_subtree_gap; /* Second cache line starts here. */ struct mm_struct *vm_mm; /* The address space we belong to. */ pgprot_t vm_page_prot; /* Access permissions of this VMA. */ unsigned long vm_flags; /* Flags, see mm.h. */ /* * For areas with an address space and backing store, * linkage into the address_space->i_mmap interval tree. */ struct { struct rb_node rb; unsigned long rb_subtree_last; } shared; /* * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma * list, after a COW of one of the file pages. A MAP_SHARED vma * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack * or brk vma (with NULL file) can only be in an anon_vma list. */ struct list_head anon_vma_chain; /* Serialized by mmap_sem & * page_table_lock */ struct anon_vma *anon_vma; /* Serialized by page_table_lock */ /* Function pointers to deal with this struct. */ const struct vm_operations_struct *vm_ops; /* Information about our backing store: */ unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE units */ struct file * vm_file; /* File we map to (can be NULL). */ void * vm_private_data; /* was vm_pte (shared mem) */ atomic_long_t swap_readahead_info; #ifndef CONFIG_MMU struct vm_region *vm_region; /* NOMMU mapping region */ #endif #ifdef CONFIG_NUMA struct mempolicy *vm_policy; /* NUMA policy for the VMA */ #endif struct vm_userfaultfd_ctx vm_userfaultfd_ctx; } __randomize_layout; struct core_thread { struct task_struct *task; struct core_thread *next; }; struct core_state { atomic_t nr_threads; struct core_thread dumper; struct completion startup; }; struct kioctx_table; struct mm_struct { struct vm_area_struct *mmap; /* list of VMAs */ struct rb_root mm_rb; u64 vmacache_seqnum; /* per-thread vmacache */ #ifdef CONFIG_MMU unsigned long (*get_unmapped_area) (struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #endif unsigned long mmap_base; /* base of mmap area */ unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ #ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES /* Base adresses for compatible mmap() */ unsigned long mmap_compat_base; unsigned long mmap_compat_legacy_base; #endif unsigned long task_size; /* size of task vm space */ unsigned long highest_vm_end; /* highest vma end address */ pgd_t * pgd; /** * @mm_users: The number of users including userspace. * * Use mmget()/mmget_not_zero()/mmput() to modify. When this drops * to 0 (i.e. when the task exits and there are no other temporary * reference holders), we also release a reference on @mm_count * (which may then free the &struct mm_struct if @mm_count also * drops to 0). */ atomic_t mm_users; /** * @mm_count: The number of references to &struct mm_struct * (@mm_users count as 1). * * Use mmgrab()/mmdrop() to modify. When this drops to 0, the * &struct mm_struct is freed. */ atomic_t mm_count; atomic_long_t nr_ptes; /* PTE page table pages */ #if CONFIG_PGTABLE_LEVELS > 2 atomic_long_t nr_pmds; /* PMD page table pages */ #endif int map_count; /* number of VMAs */ spinlock_t page_table_lock; /* Protects page tables and some counters */ struct rw_semaphore mmap_sem; struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung * together off init_mm.mmlist, and are protected * by mmlist_lock */ unsigned long hiwater_rss; /* High-watermark of RSS usage */ unsigned long hiwater_vm; /* High-water virtual memory usage */ unsigned long total_vm; /* Total pages mapped */ unsigned long locked_vm; /* Pages that have PG_mlocked set */ unsigned long pinned_vm; /* Refcount permanently increased */ unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ unsigned long stack_vm; /* VM_STACK */ unsigned long def_flags; unsigned long start_code, end_code, start_data, end_data; unsigned long start_brk, brk, start_stack; unsigned long arg_start, arg_end, env_start, env_end; unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */ /* * Special counters, in some configurations protected by the * page_table_lock, in other configurations by being atomic. */ struct mm_rss_stat rss_stat; struct linux_binfmt *binfmt; cpumask_var_t cpu_vm_mask_var; /* Architecture-specific MM context */ mm_context_t context; unsigned long flags; /* Must use atomic bitops to access the bits */ struct core_state *core_state; /* coredumping support */ #ifdef CONFIG_MEMBARRIER atomic_t membarrier_state; #endif #ifdef CONFIG_AIO spinlock_t ioctx_lock; struct kioctx_table __rcu *ioctx_table; #endif #ifdef CONFIG_MEMCG /* * "owner" points to a task that is regarded as the canonical * user/owner of this mm. All of the following must be true in * order for it to be changed: * * current == mm->owner * current->mm != mm * new_owner->mm == mm * new_owner->alloc_lock is held */ struct task_struct __rcu *owner; #endif struct user_namespace *user_ns; /* store ref to file /proc//exe symlink points to */ struct file __rcu *exe_file; #ifdef CONFIG_MMU_NOTIFIER struct mmu_notifier_mm *mmu_notifier_mm; #endif #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS pgtable_t pmd_huge_pte; /* protected by page_table_lock */ #endif #ifdef CONFIG_CPUMASK_OFFSTACK struct cpumask cpumask_allocation; #endif #ifdef CONFIG_NUMA_BALANCING /* * numa_next_scan is the next time that the PTEs will be marked * pte_numa. NUMA hinting faults will gather statistics and migrate * pages to new nodes if necessary. */ unsigned long numa_next_scan; /* Restart point for scanning and setting pte_numa */ unsigned long numa_scan_offset; /* numa_scan_seq prevents two threads setting pte_numa */ int numa_scan_seq; #endif /* * An operation with batched TLB flushing is going on. Anything that * can move process memory needs to flush the TLB when moving a * PROT_NONE or PROT_NUMA mapped page. */ atomic_t tlb_flush_pending; #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH /* See flush_tlb_batched_pending() */ bool tlb_flush_batched; #endif struct uprobes_state uprobes_state; #ifdef CONFIG_HUGETLB_PAGE atomic_long_t hugetlb_usage; #endif struct work_struct async_put_work; #if IS_ENABLED(CONFIG_HMM) /* HMM needs to track a few things per mm */ struct hmm *hmm; #endif } __randomize_layout; extern struct mm_struct init_mm; static inline void mm_init_cpumask(struct mm_struct *mm) { #ifdef CONFIG_CPUMASK_OFFSTACK mm->cpu_vm_mask_var = &mm->cpumask_allocation; #endif cpumask_clear(mm->cpu_vm_mask_var); } /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ static inline cpumask_t *mm_cpumask(struct mm_struct *mm) { return mm->cpu_vm_mask_var; } struct mmu_gather; extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end); extern void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end); static inline void init_tlb_flush_pending(struct mm_struct *mm) { atomic_set(&mm->tlb_flush_pending, 0); } static inline void inc_tlb_flush_pending(struct mm_struct *mm) { atomic_inc(&mm->tlb_flush_pending); /* * The only time this value is relevant is when there are indeed pages * to flush. And we'll only flush pages after changing them, which * requires the PTL. * * So the ordering here is: * * atomic_inc(&mm->tlb_flush_pending); * spin_lock(&ptl); * ... * set_pte_at(); * spin_unlock(&ptl); * * spin_lock(&ptl) * mm_tlb_flush_pending(); * .... * spin_unlock(&ptl); * * flush_tlb_range(); * atomic_dec(&mm->tlb_flush_pending); * * Where the increment if constrained by the PTL unlock, it thus * ensures that the increment is visible if the PTE modification is * visible. After all, if there is no PTE modification, nobody cares * about TLB flushes either. * * This very much relies on users (mm_tlb_flush_pending() and * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc * locks (PPC) the unlock of one doesn't order against the lock of * another PTL. * * The decrement is ordered by the flush_tlb_range(), such that * mm_tlb_flush_pending() will not return false unless all flushes have * completed. */ } static inline void dec_tlb_flush_pending(struct mm_struct *mm) { /* * See inc_tlb_flush_pending(). * * This cannot be smp_mb__before_atomic() because smp_mb() simply does * not order against TLB invalidate completion, which is what we need. * * Therefore we must rely on tlb_flush_*() to guarantee order. */ atomic_dec(&mm->tlb_flush_pending); } static inline bool mm_tlb_flush_pending(struct mm_struct *mm) { /* * Must be called after having acquired the PTL; orders against that * PTLs release and therefore ensures that if we observe the modified * PTE we must also observe the increment from inc_tlb_flush_pending(). * * That is, it only guarantees to return true if there is a flush * pending for _this_ PTL. */ return atomic_read(&mm->tlb_flush_pending); } static inline bool mm_tlb_flush_nested(struct mm_struct *mm) { /* * Similar to mm_tlb_flush_pending(), we must have acquired the PTL * for which there is a TLB flush pending in order to guarantee * we've seen both that PTE modification and the increment. * * (no requirement on actually still holding the PTL, that is irrelevant) */ return atomic_read(&mm->tlb_flush_pending) > 1; } struct vm_fault; struct vm_special_mapping { const char *name; /* The name, e.g. "[vdso]". */ /* * If .fault is not provided, this points to a * NULL-terminated array of pages that back the special mapping. * * This must not be NULL unless .fault is provided. */ struct page **pages; /* * If non-NULL, then this is called to resolve page faults * on the special mapping. If used, .pages is not checked. */ int (*fault)(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf); int (*mremap)(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma); }; enum tlb_flush_reason { TLB_FLUSH_ON_TASK_SWITCH, TLB_REMOTE_SHOOTDOWN, TLB_LOCAL_SHOOTDOWN, TLB_LOCAL_MM_SHOOTDOWN, TLB_REMOTE_SEND_IPI, NR_TLB_FLUSH_REASONS, }; /* * A swap entry has to fit into a "unsigned long", as the entry is hidden * in the "index" field of the swapper address space. */ typedef struct { unsigned long val; } swp_entry_t; #endif /* _LINUX_MM_TYPES_H */