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