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 vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
  32
  33extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
  34                            unsigned long src_start, unsigned long len,
  35                            bool *mmap_changing);
  36extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
  37                              unsigned long dst_start,
  38                              unsigned long len,
  39                              bool *mmap_changing);
  40
  41/* mm helpers */
  42static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  43                                        struct vm_userfaultfd_ctx vm_ctx)
  44{
  45        return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
  46}
  47
  48static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  49{
  50        return vma->vm_flags & VM_UFFD_MISSING;
  51}
  52
  53static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  54{
  55        return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  56}
  57
  58extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
  59extern void dup_userfaultfd_complete(struct list_head *);
  60
  61extern void mremap_userfaultfd_prep(struct vm_area_struct *,
  62                                    struct vm_userfaultfd_ctx *);
  63extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
  64                                        unsigned long from, unsigned long to,
  65                                        unsigned long len);
  66
  67extern bool userfaultfd_remove(struct vm_area_struct *vma,
  68                               unsigned long start,
  69                               unsigned long end);
  70
  71extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
  72                                  unsigned long start, unsigned long end,
  73                                  struct list_head *uf);
  74extern void userfaultfd_unmap_complete(struct mm_struct *mm,
  75                                       struct list_head *uf);
  76
  77#else /* CONFIG_USERFAULTFD */
  78
  79/* mm helpers */
  80static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
  81                                unsigned long reason)
  82{
  83        return VM_FAULT_SIGBUS;
  84}
  85
  86static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  87                                        struct vm_userfaultfd_ctx vm_ctx)
  88{
  89        return true;
  90}
  91
  92static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  93{
  94        return false;
  95}
  96
  97static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  98{
  99        return false;
 100}
 101
 102static inline int dup_userfaultfd(struct vm_area_struct *vma,
 103                                  struct list_head *l)
 104{
 105        return 0;
 106}
 107
 108static inline void dup_userfaultfd_complete(struct list_head *l)
 109{
 110}
 111
 112static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
 113                                           struct vm_userfaultfd_ctx *ctx)
 114{
 115}
 116
 117static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
 118                                               unsigned long from,
 119                                               unsigned long to,
 120                                               unsigned long len)
 121{
 122}
 123
 124static inline bool userfaultfd_remove(struct vm_area_struct *vma,
 125                                      unsigned long start,
 126                                      unsigned long end)
 127{
 128        return true;
 129}
 130
 131static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
 132                                         unsigned long start, unsigned long end,
 133                                         struct list_head *uf)
 134{
 135        return 0;
 136}
 137
 138static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
 139                                              struct list_head *uf)
 140{
 141}
 142
 143#endif /* CONFIG_USERFAULTFD */
 144
 145#endif /* _LINUX_USERFAULTFD_K_H */
 146