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