LXR linux/include/linux/userfaultfd

   1/*
   2 *  include/linux/userfaultfd_k.h
   3 *
   4 *  Copyright (C) 2015  Red Hat, Inc.
   5 *
   6 */
   7
   8#ifndef _LINUX_USERFAULTFD_K_H
   9#define _LINUX_USERFAULTFD_K_H
  10
  11#ifdef CONFIG_USERFAULTFD
  12
  13#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
  14
  15#include <linux/fcntl.h>
  16
  17/*
  18 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
  19 * new flags, since they might collide with O_* ones. We want
  20 * to re-use O_* flags that couldn't possibly have a meaning
  21 * from userfaultfd, in order to leave a free define-space for
  22 * shared O_* flags.
  23 */
  24#define UFFD_CLOEXEC O_CLOEXEC
  25#define UFFD_NONBLOCK O_NONBLOCK
  26
  27#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
  28#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
  29
  30extern int handle_userfault(struct vm_area_struct *vma, unsigned long address,
  31                            unsigned int flags, 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
  56#else /* CONFIG_USERFAULTFD */
  57
  58/* mm helpers */
  59static inline int handle_userfault(struct vm_area_struct *vma,
  60                                   unsigned long address,
  61                                   unsigned int flags,
  62                                   unsigned long reason)
  63{
  64        return VM_FAULT_SIGBUS;
  65}
  66
  67static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  68                                        struct vm_userfaultfd_ctx vm_ctx)
  69{
  70        return true;
  71}
  72
  73static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  74{
  75        return false;
  76}
  77
  78static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  79{
  80        return false;
  81}
  82
  83#endif /* CONFIG_USERFAULTFD */
  84
  85#endif /* _LINUX_USERFAULTFD_K_H */
  86