include/linux/userfaultfd_k.h

   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
  30 extern int handle_userfault(struct vm_area_struct *vma, unsigned long address,
  31                             unsigned int flags, unsigned long reason);
  32
  33 /* mm helpers */
  34 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  35                                         struct vm_userfaultfd_ctx vm_ctx)
  36 {
  37         return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
  38 }
  39
  40 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  41 {
  42         return vma->vm_flags & VM_UFFD_MISSING;
  43 }
  44
  45 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  46 {
  47         return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  48 }
  49
  50 #else /* CONFIG_USERFAULTFD */
  51
  52 /* mm helpers */
  53 static inline int handle_userfault(struct vm_area_struct *vma,
  54                                    unsigned long address,
  55                                    unsigned int flags,
  56                                    unsigned long reason)
  57 {
  58         return VM_FAULT_SIGBUS;
  59 }
  60
  61 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  62                                         struct vm_userfaultfd_ctx vm_ctx)
  63 {
  64         return true;
  65 }
  66
  67 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  68 {
  69         return false;
  70 }
  71
  72 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  73 {
  74         return false;
  75 }
  76
  77 #endif /* CONFIG_USERFAULTFD */
  78
  79 #endif /* _LINUX_USERFAULTFD_K_H */