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_fault *vmf, unsigned long reason);
  31
  32 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
  33                             unsigned long src_start, unsigned long len);
  34 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
  35                               unsigned long dst_start,
  36                               unsigned long len);
  37
  38 /* mm helpers */
  39 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  40                                         struct vm_userfaultfd_ctx vm_ctx)
  41 {
  42         return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
  43 }
  44
  45 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  46 {
  47         return vma->vm_flags & VM_UFFD_MISSING;
  48 }
  49
  50 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  51 {
  52         return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  53 }
  54
  55 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
  56 extern void dup_userfaultfd_complete(struct list_head *);
  57
  58 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
  59                                     struct vm_userfaultfd_ctx *);
  60 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
  61                                         unsigned long from, unsigned long to,
  62                                         unsigned long len);
  63
  64 extern bool userfaultfd_remove(struct vm_area_struct *vma,
  65                                unsigned long start,
  66                                unsigned long end);
  67
  68 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
  69                                   unsigned long start, unsigned long end,
  70                                   struct list_head *uf);
  71 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
  72                                        struct list_head *uf);
  73
  74 #else /* CONFIG_USERFAULTFD */
  75
  76 /* mm helpers */
  77 static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
  78 {
  79         return VM_FAULT_SIGBUS;
  80 }
  81
  82 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  83                                         struct vm_userfaultfd_ctx vm_ctx)
  84 {
  85         return true;
  86 }
  87
  88 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  89 {
  90         return false;
  91 }
  92
  93 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  94 {
  95         return false;
  96 }
  97
  98 static inline int dup_userfaultfd(struct vm_area_struct *vma,
  99                                   struct list_head *l)
 100 {
 101         return 0;
 102 }
 103
 104 static inline void dup_userfaultfd_complete(struct list_head *l)
 105 {
 106 }
 107
 108 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
 109                                            struct vm_userfaultfd_ctx *ctx)
 110 {
 111 }
 112
 113 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
 114                                                unsigned long from,
 115                                                unsigned long to,
 116                                                unsigned long len)
 117 {
 118 }
 119
 120 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
 121                                       unsigned long start,
 122                                       unsigned long end)
 123 {
 124         return true;
 125 }
 126
 127 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
 128                                          unsigned long start, unsigned long end,
 129                                          struct list_head *uf)
 130 {
 131         return 0;
 132 }
 133
 134 static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
 135                                               struct list_head *uf)
 136 {
 137 }
 138
 139 #endif /* CONFIG_USERFAULTFD */
 140
 141 #endif /* _LINUX_USERFAULTFD_K_H */