include/linux/userfaultfd_k.h

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