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 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
  36                               unsigned long dst_start,
  37                               unsigned long len);
  38
  39 /* mm helpers */
  40 static 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
  46 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  47 {
  48         return vma->vm_flags & VM_UFFD_MISSING;
  49 }
  50
  51 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  52 {
  53         return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  54 }
  55
  56 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
  57 extern void dup_userfaultfd_complete(struct list_head *);
  58
  59 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
  60                                     struct vm_userfaultfd_ctx *);
  61 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
  62                                         unsigned long from, unsigned long to,
  63                                         unsigned long len);
  64
  65 extern bool userfaultfd_remove(struct vm_area_struct *vma,
  66                                unsigned long start,
  67                                unsigned long end);
  68
  69 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
  70                                   unsigned long start, unsigned long end,
  71                                   struct list_head *uf);
  72 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
  73                                        struct list_head *uf);
  74
  75 #else /* CONFIG_USERFAULTFD */
  76
  77 /* mm helpers */
  78 static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
  79 {
  80         return VM_FAULT_SIGBUS;
  81 }
  82
  83 static 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
  89 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  90 {
  91         return false;
  92 }
  93
  94 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  95 {
  96         return false;
  97 }
  98
  99 static inline int dup_userfaultfd(struct vm_area_struct *vma,
 100                                   struct list_head *l)
 101 {
 102         return 0;
 103 }
 104
 105 static inline void dup_userfaultfd_complete(struct list_head *l)
 106 {
 107 }
 108
 109 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
 110                                            struct vm_userfaultfd_ctx *ctx)
 111 {
 112 }
 113
 114 static 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
 121 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
 122                                       unsigned long start,
 123                                       unsigned long end)
 124 {
 125         return true;
 126 }
 127
 128 static 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
 135 static 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 */