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