| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * include/linux/userfaultfd_k.h |
| * |
| * Copyright (C) 2015 Red Hat, Inc. |
| * |
| */ |
| |
| #ifndef _LINUX_USERFAULTFD_K_H |
| #define _LINUX_USERFAULTFD_K_H |
| |
| #ifdef CONFIG_USERFAULTFD |
| |
| #include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */ |
| |
| #include <linux/fcntl.h> |
| #include <linux/mm.h> |
| #include <asm-generic/pgtable_uffd.h> |
| |
| /* The set of all possible UFFD-related VM flags. */ |
| #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR) |
| |
| /* |
| * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining |
| * new flags, since they might collide with O_* ones. We want |
| * to re-use O_* flags that couldn't possibly have a meaning |
| * from userfaultfd, in order to leave a free define-space for |
| * shared O_* flags. |
| */ |
| #define UFFD_CLOEXEC O_CLOEXEC |
| #define UFFD_NONBLOCK O_NONBLOCK |
| |
| #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) |
| #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) |
| |
| extern int sysctl_unprivileged_userfaultfd; |
| |
| extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); |
| |
| /* |
| * The mode of operation for __mcopy_atomic and its helpers. |
| * |
| * This is almost an implementation detail (mcopy_atomic below doesn't take this |
| * as a parameter), but it's exposed here because memory-kind-specific |
| * implementations (e.g. hugetlbfs) need to know the mode of operation. |
| */ |
| enum mcopy_atomic_mode { |
| /* A normal copy_from_user into the destination range. */ |
| MCOPY_ATOMIC_NORMAL, |
| /* Don't copy; map the destination range to the zero page. */ |
| MCOPY_ATOMIC_ZEROPAGE, |
| /* Just install pte(s) with the existing page(s) in the page cache. */ |
| MCOPY_ATOMIC_CONTINUE, |
| }; |
| |
| extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, |
| struct vm_area_struct *dst_vma, |
| unsigned long dst_addr, struct page *page, |
| bool newly_allocated, bool wp_copy); |
| |
| extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, |
| unsigned long src_start, unsigned long len, |
| atomic_t *mmap_changing, __u64 mode); |
| extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, |
| unsigned long dst_start, |
| unsigned long len, |
| atomic_t *mmap_changing); |
| extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start, |
| unsigned long len, atomic_t *mmap_changing); |
| extern int mwriteprotect_range(struct mm_struct *dst_mm, |
| unsigned long start, unsigned long len, |
| bool enable_wp, atomic_t *mmap_changing); |
| |
| /* mm helpers */ |
| static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, |
| struct vm_userfaultfd_ctx vm_ctx) |
| { |
| return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; |
| } |
| |
| /* |
| * Never enable huge pmd sharing on some uffd registered vmas: |
| * |
| * - VM_UFFD_WP VMAs, because write protect information is per pgtable entry. |
| * |
| * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for |
| * VMAs which share huge pmds. (If you have two mappings to the same |
| * underlying pages, and fault in the non-UFFD-registered one with a write, |
| * with huge pmd sharing this would *also* setup the second UFFD-registered |
| * mapping, and we'd not get minor faults.) |
| */ |
| static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); |
| } |
| |
| static inline bool userfaultfd_missing(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & VM_UFFD_MISSING; |
| } |
| |
| static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & VM_UFFD_WP; |
| } |
| |
| static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & VM_UFFD_MINOR; |
| } |
| |
| static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
| pte_t pte) |
| { |
| return userfaultfd_wp(vma) && pte_uffd_wp(pte); |
| } |
| |
| static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, |
| pmd_t pmd) |
| { |
| return userfaultfd_wp(vma) && pmd_uffd_wp(pmd); |
| } |
| |
| static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & __VM_UFFD_FLAGS; |
| } |
| |
| extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); |
| extern void dup_userfaultfd_complete(struct list_head *); |
| |
| extern void mremap_userfaultfd_prep(struct vm_area_struct *, |
| struct vm_userfaultfd_ctx *); |
| extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, |
| unsigned long from, unsigned long to, |
| unsigned long len); |
| |
| extern bool userfaultfd_remove(struct vm_area_struct *vma, |
| unsigned long start, |
| unsigned long end); |
| |
| extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, |
| unsigned long start, unsigned long end, |
| struct list_head *uf); |
| extern void userfaultfd_unmap_complete(struct mm_struct *mm, |
| struct list_head *uf); |
| |
| #else /* CONFIG_USERFAULTFD */ |
| |
| /* mm helpers */ |
| static inline vm_fault_t handle_userfault(struct vm_fault *vmf, |
| unsigned long reason) |
| { |
| return VM_FAULT_SIGBUS; |
| } |
| |
| static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, |
| struct vm_userfaultfd_ctx vm_ctx) |
| { |
| return true; |
| } |
| |
| static inline bool userfaultfd_missing(struct vm_area_struct *vma) |
| { |
| return false; |
| } |
| |
| static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
| { |
| return false; |
| } |
| |
| static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
| { |
| return false; |
| } |
| |
| static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
| pte_t pte) |
| { |
| return false; |
| } |
| |
| static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, |
| pmd_t pmd) |
| { |
| return false; |
| } |
| |
| |
| static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
| { |
| return false; |
| } |
| |
| static inline int dup_userfaultfd(struct vm_area_struct *vma, |
| struct list_head *l) |
| { |
| return 0; |
| } |
| |
| static inline void dup_userfaultfd_complete(struct list_head *l) |
| { |
| } |
| |
| static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, |
| struct vm_userfaultfd_ctx *ctx) |
| { |
| } |
| |
| static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, |
| unsigned long from, |
| unsigned long to, |
| unsigned long len) |
| { |
| } |
| |
| static inline bool userfaultfd_remove(struct vm_area_struct *vma, |
| unsigned long start, |
| unsigned long end) |
| { |
| return true; |
| } |
| |
| static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, |
| unsigned long start, unsigned long end, |
| struct list_head *uf) |
| { |
| return 0; |
| } |
| |
| static inline void userfaultfd_unmap_complete(struct mm_struct *mm, |
| struct list_head *uf) |
| { |
| } |
| |
| #endif /* CONFIG_USERFAULTFD */ |
| |
| #endif /* _LINUX_USERFAULTFD_K_H */ |