LXR linux/include/linux/userfaultfd

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 *  include/linux/userfaultfd_k.h
   4 *
   5 *  Copyright (C) 2015  Red Hat, Inc.
   6 *
   7 */
   8
   9#ifndef _LINUX_USERFAULTFD_K_H
  10#define _LINUX_USERFAULTFD_K_H
  11
  12#ifdef CONFIG_USERFAULTFD
  13
  14#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
  15
  16#include <linux/fcntl.h>
  17
  18/*
  19 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
  20 * new flags, since they might collide with O_* ones. We want
  21 * to re-use O_* flags that couldn't possibly have a meaning
  22 * from userfaultfd, in order to leave a free define-space for
  23 * shared O_* flags.
  24 */
  25#define UFFD_CLOEXEC O_CLOEXEC
  26#define UFFD_NONBLOCK O_NONBLOCK
  27
  28#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
  29#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
  30
  31extern int sysctl_unprivileged_userfaultfd;
  32
  33extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
  34
  35extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
  36                            unsigned long src_start, unsigned long len,
  37                            bool *mmap_changing);
  38extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
  39                              unsigned long dst_start,
  40                              unsigned long len,
  41                              bool *mmap_changing);
  42
  43/* mm helpers */
  44static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  45                                        struct vm_userfaultfd_ctx vm_ctx)
  46{
  47        return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
  48}
  49
  50static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  51{
  52        return vma->vm_flags & VM_UFFD_MISSING;
  53}
  54
  55static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  56{
  57        return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  58}
  59
  60extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
  61extern void dup_userfaultfd_complete(struct list_head *);
  62
  63extern void mremap_userfaultfd_prep(struct vm_area_struct *,
  64                                    struct vm_userfaultfd_ctx *);
  65extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
  66                                        unsigned long from, unsigned long to,
  67                                        unsigned long len);
  68
  69extern bool userfaultfd_remove(struct vm_area_struct *vma,
  70                               unsigned long start,
  71                               unsigned long end);
  72
  73extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
  74                                  unsigned long start, unsigned long end,
  75                                  struct list_head *uf);
  76extern void userfaultfd_unmap_complete(struct mm_struct *mm,
  77                                       struct list_head *uf);
  78
  79#else /* CONFIG_USERFAULTFD */
  80
  81/* mm helpers */
  82static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
  83                                unsigned long reason)
  84{
  85        return VM_FAULT_SIGBUS;
  86}
  87
  88static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  89                                        struct vm_userfaultfd_ctx vm_ctx)
  90{
  91        return true;
  92}
  93
  94static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  95{
  96        return false;
  97}
  98
  99static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 100{
 101        return false;
 102}
 103
 104static inline int dup_userfaultfd(struct vm_area_struct *vma,
 105                                  struct list_head *l)
 106{
 107        return 0;
 108}
 109
 110static inline void dup_userfaultfd_complete(struct list_head *l)
 111{
 112}
 113
 114static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
 115                                           struct vm_userfaultfd_ctx *ctx)
 116{
 117}
 118
 119static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
 120                                               unsigned long from,
 121                                               unsigned long to,
 122                                               unsigned long len)
 123{
 124}
 125
 126static inline bool userfaultfd_remove(struct vm_area_struct *vma,
 127                                      unsigned long start,
 128                                      unsigned long end)
 129{
 130        return true;
 131}
 132
 133static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
 134                                         unsigned long start, unsigned long end,
 135                                         struct list_head *uf)
 136{
 137        return 0;
 138}
 139
 140static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
 141                                              struct list_head *uf)
 142{
 143}
 144
 145#endif /* CONFIG_USERFAULTFD */
 146
 147#endif /* _LINUX_USERFAULTFD_K_H */
 148