diff options
Diffstat (limited to 'mm/vma.h')
| -rw-r--r-- | mm/vma.h | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/mm/vma.h b/mm/vma.h new file mode 100644 index 000000000000..f47112a352db --- /dev/null +++ b/mm/vma.h @@ -0,0 +1,620 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * vma.h + * + * Core VMA manipulation API implemented in vma.c. + */ +#ifndef __MM_VMA_H +#define __MM_VMA_H + +/* + * VMA lock generalization + */ +struct vma_prepare { + struct vm_area_struct *vma; + struct vm_area_struct *adj_next; + struct file *file; + struct address_space *mapping; + struct anon_vma *anon_vma; + struct vm_area_struct *insert; + struct vm_area_struct *remove; + struct vm_area_struct *remove2; + + bool skip_vma_uprobe :1; +}; + +struct unlink_vma_file_batch { + int count; + struct vm_area_struct *vmas[8]; +}; + +/* + * vma munmap operation + */ +struct vma_munmap_struct { + struct vma_iterator *vmi; + struct vm_area_struct *vma; /* The first vma to munmap */ + struct vm_area_struct *prev; /* vma before the munmap area */ + struct vm_area_struct *next; /* vma after the munmap area */ + struct list_head *uf; /* Userfaultfd list_head */ + unsigned long start; /* Aligned start addr (inclusive) */ + unsigned long end; /* Aligned end addr (exclusive) */ + unsigned long unmap_start; /* Unmap PTE start */ + unsigned long unmap_end; /* Unmap PTE end */ + int vma_count; /* Number of vmas that will be removed */ + bool unlock; /* Unlock after the munmap */ + bool clear_ptes; /* If there are outstanding PTE to be cleared */ + /* 2 byte hole */ + unsigned long nr_pages; /* Number of pages being removed */ + unsigned long locked_vm; /* Number of locked pages */ + unsigned long nr_accounted; /* Number of VM_ACCOUNT pages */ + unsigned long exec_vm; + unsigned long stack_vm; + unsigned long data_vm; +}; + +enum vma_merge_state { + VMA_MERGE_START, + VMA_MERGE_ERROR_NOMEM, + VMA_MERGE_NOMERGE, + VMA_MERGE_SUCCESS, +}; + +/* + * Describes a VMA merge operation and is threaded throughout it. + * + * Any of the fields may be mutated by the merge operation, so no guarantees are + * made to the contents of this structure after a merge operation has completed. + */ +struct vma_merge_struct { + struct mm_struct *mm; + struct vma_iterator *vmi; + /* + * Adjacent VMAs, any of which may be NULL if not present: + * + * |------|--------|------| + * | prev | middle | next | + * |------|--------|------| + * + * middle may not yet exist in the case of a proposed new VMA being + * merged, or it may be an existing VMA. + * + * next may be assigned by the caller. + */ + struct vm_area_struct *prev; + struct vm_area_struct *middle; + struct vm_area_struct *next; + /* This is the VMA we ultimately target to become the merged VMA. */ + struct vm_area_struct *target; + /* + * Initially, the start, end, pgoff fields are provided by the caller + * and describe the proposed new VMA range, whether modifying an + * existing VMA (which will be 'middle'), or adding a new one. + * + * During the merge process these fields are updated to describe the new + * range _including those VMAs which will be merged_. + */ + unsigned long start; + unsigned long end; + pgoff_t pgoff; + + unsigned long flags; + struct file *file; + struct anon_vma *anon_vma; + struct mempolicy *policy; + struct vm_userfaultfd_ctx uffd_ctx; + struct anon_vma_name *anon_name; + enum vma_merge_state state; + + /* Flags which callers can use to modify merge behaviour: */ + + /* + * If we can expand, simply do so. We know there is nothing to merge to + * the right. Does not reset state upon failure to merge. The VMA + * iterator is assumed to be positioned at the previous VMA, rather than + * at the gap. + */ + bool just_expand :1; + + /* + * If a merge is possible, but an OOM error occurs, give up and don't + * execute the merge, returning NULL. + */ + bool give_up_on_oom :1; + + /* + * If set, skip uprobe_mmap upon merged vma. + */ + bool skip_vma_uprobe :1; + + /* Internal flags set during merge process: */ + + /* + * Internal flag indicating the merge increases vmg->middle->vm_start + * (and thereby, vmg->prev->vm_end). + */ + bool __adjust_middle_start :1; + /* + * Internal flag indicating the merge decreases vmg->next->vm_start + * (and thereby, vmg->middle->vm_end). + */ + bool __adjust_next_start :1; + /* + * Internal flag used during the merge operation to indicate we will + * remove vmg->middle. + */ + bool __remove_middle :1; + /* + * Internal flag used during the merge operationr to indicate we will + * remove vmg->next. + */ + bool __remove_next :1; + +}; + +static inline bool vmg_nomem(struct vma_merge_struct *vmg) +{ + return vmg->state == VMA_MERGE_ERROR_NOMEM; +} + +/* Assumes addr >= vma->vm_start. */ +static inline pgoff_t vma_pgoff_offset(struct vm_area_struct *vma, + unsigned long addr) +{ + return vma->vm_pgoff + PHYS_PFN(addr - vma->vm_start); +} + +#define VMG_STATE(name, mm_, vmi_, start_, end_, flags_, pgoff_) \ + struct vma_merge_struct name = { \ + .mm = mm_, \ + .vmi = vmi_, \ + .start = start_, \ + .end = end_, \ + .flags = flags_, \ + .pgoff = pgoff_, \ + .state = VMA_MERGE_START, \ + } + +#define VMG_VMA_STATE(name, vmi_, prev_, vma_, start_, end_) \ + struct vma_merge_struct name = { \ + .mm = vma_->vm_mm, \ + .vmi = vmi_, \ + .prev = prev_, \ + .middle = vma_, \ + .next = NULL, \ + .start = start_, \ + .end = end_, \ + .flags = vma_->vm_flags, \ + .pgoff = vma_pgoff_offset(vma_, start_), \ + .file = vma_->vm_file, \ + .anon_vma = vma_->anon_vma, \ + .policy = vma_policy(vma_), \ + .uffd_ctx = vma_->vm_userfaultfd_ctx, \ + .anon_name = anon_vma_name(vma_), \ + .state = VMA_MERGE_START, \ + } + +#ifdef CONFIG_DEBUG_VM_MAPLE_TREE +void validate_mm(struct mm_struct *mm); +#else +#define validate_mm(mm) do { } while (0) +#endif + +__must_check int vma_expand(struct vma_merge_struct *vmg); +__must_check int vma_shrink(struct vma_iterator *vmi, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, pgoff_t pgoff); + +static inline int vma_iter_store_gfp(struct vma_iterator *vmi, + struct vm_area_struct *vma, gfp_t gfp) + +{ + if (vmi->mas.status != ma_start && + ((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start))) + vma_iter_invalidate(vmi); + + __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1); + mas_store_gfp(&vmi->mas, vma, gfp); + if (unlikely(mas_is_err(&vmi->mas))) + return -ENOMEM; + + vma_mark_attached(vma); + return 0; +} + + +/* + * Temporary helper functions for file systems which wrap an invocation of + * f_op->mmap() but which might have an underlying file system which implements + * f_op->mmap_prepare(). + */ + +static inline struct vm_area_desc *vma_to_desc(struct vm_area_struct *vma, + struct vm_area_desc *desc) +{ + desc->mm = vma->vm_mm; + desc->start = vma->vm_start; + desc->end = vma->vm_end; + + desc->pgoff = vma->vm_pgoff; + desc->file = vma->vm_file; + desc->vm_flags = vma->vm_flags; + desc->page_prot = vma->vm_page_prot; + + desc->vm_ops = NULL; + desc->private_data = NULL; + + return desc; +} + +static inline void set_vma_from_desc(struct vm_area_struct *vma, + struct vm_area_desc *desc) +{ + /* + * Since we're invoking .mmap_prepare() despite having a partially + * established VMA, we must take care to handle setting fields + * correctly. + */ + + /* Mutable fields. Populated with initial state. */ + vma->vm_pgoff = desc->pgoff; + if (vma->vm_file != desc->file) + vma_set_file(vma, desc->file); + if (vma->vm_flags != desc->vm_flags) + vm_flags_set(vma, desc->vm_flags); + vma->vm_page_prot = desc->page_prot; + + /* User-defined fields. */ + vma->vm_ops = desc->vm_ops; + vma->vm_private_data = desc->private_data; +} + +int +do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, + struct mm_struct *mm, unsigned long start, + unsigned long end, struct list_head *uf, bool unlock); + +int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, + unsigned long start, size_t len, struct list_head *uf, + bool unlock); + +void remove_vma(struct vm_area_struct *vma); + +void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, + struct vm_area_struct *prev, struct vm_area_struct *next); + +/* We are about to modify the VMA's flags. */ +__must_check struct vm_area_struct +*vma_modify_flags(struct vma_iterator *vmi, + struct vm_area_struct *prev, struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long new_flags); + +/* We are about to modify the VMA's flags and/or anon_name. */ +__must_check struct vm_area_struct +*vma_modify_flags_name(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, + unsigned long end, + unsigned long new_flags, + struct anon_vma_name *new_name); + +/* We are about to modify the VMA's memory policy. */ +__must_check struct vm_area_struct +*vma_modify_policy(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct mempolicy *new_pol); + +/* We are about to modify the VMA's flags and/or uffd context. */ +__must_check struct vm_area_struct +*vma_modify_flags_uffd(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long new_flags, + struct vm_userfaultfd_ctx new_ctx, + bool give_up_on_oom); + +__must_check struct vm_area_struct +*vma_merge_new_range(struct vma_merge_struct *vmg); + +__must_check struct vm_area_struct +*vma_merge_extend(struct vma_iterator *vmi, + struct vm_area_struct *vma, + unsigned long delta); + +void unlink_file_vma_batch_init(struct unlink_vma_file_batch *vb); + +void unlink_file_vma_batch_final(struct unlink_vma_file_batch *vb); + +void unlink_file_vma_batch_add(struct unlink_vma_file_batch *vb, + struct vm_area_struct *vma); + +void unlink_file_vma(struct vm_area_struct *vma); + +void vma_link_file(struct vm_area_struct *vma); + +int vma_link(struct mm_struct *mm, struct vm_area_struct *vma); + +struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, + unsigned long addr, unsigned long len, pgoff_t pgoff, + bool *need_rmap_locks); + +struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma); + +bool vma_needs_dirty_tracking(struct vm_area_struct *vma); +bool vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot); + +int mm_take_all_locks(struct mm_struct *mm); +void mm_drop_all_locks(struct mm_struct *mm); + +unsigned long mmap_region(struct file *file, unsigned long addr, + unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, + struct list_head *uf); + +int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma, + unsigned long addr, unsigned long request, unsigned long flags); + +unsigned long unmapped_area(struct vm_unmapped_area_info *info); +unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info); + +static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma) +{ + /* + * We want to check manually if we can change individual PTEs writable + * if we can't do that automatically for all PTEs in a mapping. For + * private mappings, that's always the case when we have write + * permissions as we properly have to handle COW. + */ + if (vma->vm_flags & VM_SHARED) + return vma_wants_writenotify(vma, vma->vm_page_prot); + return !!(vma->vm_flags & VM_WRITE); +} + +#ifdef CONFIG_MMU +static inline pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags) +{ + return pgprot_modify(oldprot, vm_get_page_prot(vm_flags)); +} +#endif + +static inline struct vm_area_struct *vma_prev_limit(struct vma_iterator *vmi, + unsigned long min) +{ + return mas_prev(&vmi->mas, min); +} + +/* + * These three helpers classifies VMAs for virtual memory accounting. + */ + +/* + * Executable code area - executable, not writable, not stack + */ +static inline bool is_exec_mapping(vm_flags_t flags) +{ + return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC; +} + +/* + * Stack area (including shadow stacks) + * + * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous: + * do_mmap() forbids all other combinations. + */ +static inline bool is_stack_mapping(vm_flags_t flags) +{ + return ((flags & VM_STACK) == VM_STACK) || (flags & VM_SHADOW_STACK); +} + +/* + * Data area - private, writable, not stack + */ +static inline bool is_data_mapping(vm_flags_t flags) +{ + return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE; +} + + +static inline void vma_iter_config(struct vma_iterator *vmi, + unsigned long index, unsigned long last) +{ + __mas_set_range(&vmi->mas, index, last - 1); +} + +static inline void vma_iter_reset(struct vma_iterator *vmi) +{ + mas_reset(&vmi->mas); +} + +static inline +struct vm_area_struct *vma_iter_prev_range_limit(struct vma_iterator *vmi, unsigned long min) +{ + return mas_prev_range(&vmi->mas, min); +} + +static inline +struct vm_area_struct *vma_iter_next_range_limit(struct vma_iterator *vmi, unsigned long max) +{ + return mas_next_range(&vmi->mas, max); +} + +static inline int vma_iter_area_lowest(struct vma_iterator *vmi, unsigned long min, + unsigned long max, unsigned long size) +{ + return mas_empty_area(&vmi->mas, min, max - 1, size); +} + +static inline int vma_iter_area_highest(struct vma_iterator *vmi, unsigned long min, + unsigned long max, unsigned long size) +{ + return mas_empty_area_rev(&vmi->mas, min, max - 1, size); +} + +/* + * VMA Iterator functions shared between nommu and mmap + */ +static inline int vma_iter_prealloc(struct vma_iterator *vmi, + struct vm_area_struct *vma) +{ + return mas_preallocate(&vmi->mas, vma, GFP_KERNEL); +} + +static inline void vma_iter_clear(struct vma_iterator *vmi) +{ + mas_store_prealloc(&vmi->mas, NULL); +} + +static inline struct vm_area_struct *vma_iter_load(struct vma_iterator *vmi) +{ + return mas_walk(&vmi->mas); +} + +/* Store a VMA with preallocated memory */ +static inline void vma_iter_store_overwrite(struct vma_iterator *vmi, + struct vm_area_struct *vma) +{ + vma_assert_attached(vma); + +#if defined(CONFIG_DEBUG_VM_MAPLE_TREE) + if (MAS_WARN_ON(&vmi->mas, vmi->mas.status != ma_start && + vmi->mas.index > vma->vm_start)) { + pr_warn("%lx > %lx\n store vma %lx-%lx\n into slot %lx-%lx\n", + vmi->mas.index, vma->vm_start, vma->vm_start, + vma->vm_end, vmi->mas.index, vmi->mas.last); + } + if (MAS_WARN_ON(&vmi->mas, vmi->mas.status != ma_start && + vmi->mas.last < vma->vm_start)) { + pr_warn("%lx < %lx\nstore vma %lx-%lx\ninto slot %lx-%lx\n", + vmi->mas.last, vma->vm_start, vma->vm_start, vma->vm_end, + vmi->mas.index, vmi->mas.last); + } +#endif + + if (vmi->mas.status != ma_start && + ((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start))) + vma_iter_invalidate(vmi); + + __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1); + mas_store_prealloc(&vmi->mas, vma); +} + +static inline void vma_iter_store_new(struct vma_iterator *vmi, + struct vm_area_struct *vma) +{ + vma_mark_attached(vma); + vma_iter_store_overwrite(vmi, vma); +} + +static inline unsigned long vma_iter_addr(struct vma_iterator *vmi) +{ + return vmi->mas.index; +} + +static inline unsigned long vma_iter_end(struct vma_iterator *vmi) +{ + return vmi->mas.last + 1; +} + +static inline int vma_iter_bulk_alloc(struct vma_iterator *vmi, + unsigned long count) +{ + return mas_expected_entries(&vmi->mas, count); +} + +static inline +struct vm_area_struct *vma_iter_prev_range(struct vma_iterator *vmi) +{ + return mas_prev_range(&vmi->mas, 0); +} + +/* + * Retrieve the next VMA and rewind the iterator to end of the previous VMA, or + * if no previous VMA, to index 0. + */ +static inline +struct vm_area_struct *vma_iter_next_rewind(struct vma_iterator *vmi, + struct vm_area_struct **pprev) +{ + struct vm_area_struct *next = vma_next(vmi); + struct vm_area_struct *prev = vma_prev(vmi); + + /* + * Consider the case where no previous VMA exists. We advance to the + * next VMA, skipping any gap, then rewind to the start of the range. + * + * If we were to unconditionally advance to the next range we'd wind up + * at the next VMA again, so we check to ensure there is a previous VMA + * to skip over. + */ + if (prev) + vma_iter_next_range(vmi); + + if (pprev) + *pprev = prev; + + return next; +} + +#ifdef CONFIG_64BIT + +static inline bool vma_is_sealed(struct vm_area_struct *vma) +{ + return (vma->vm_flags & VM_SEALED); +} + +/* + * check if a vma is sealed for modification. + * return true, if modification is allowed. + */ +static inline bool can_modify_vma(struct vm_area_struct *vma) +{ + if (unlikely(vma_is_sealed(vma))) + return false; + + return true; +} + +bool can_modify_vma_madv(struct vm_area_struct *vma, int behavior); + +#else + +static inline bool can_modify_vma(struct vm_area_struct *vma) +{ + return true; +} + +static inline bool can_modify_vma_madv(struct vm_area_struct *vma, int behavior) +{ + return true; +} + +#endif + +#if defined(CONFIG_STACK_GROWSUP) +int expand_upwards(struct vm_area_struct *vma, unsigned long address); +#endif + +int expand_downwards(struct vm_area_struct *vma, unsigned long address); + +int __vm_munmap(unsigned long start, size_t len, bool unlock); + +int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma); + +/* vma_init.h, shared between CONFIG_MMU and nommu. */ +void __init vma_state_init(void); +struct vm_area_struct *vm_area_alloc(struct mm_struct *mm); +struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig); +void vm_area_free(struct vm_area_struct *vma); + +/* vma_exec.c */ +#ifdef CONFIG_MMU +int create_init_stack_vma(struct mm_struct *mm, struct vm_area_struct **vmap, + unsigned long *top_mem_p); +int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift); +#endif + +#endif /* __MM_VMA_H */ |