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 #include <linux/mm.h>
  18 #include <asm-generic/pgtable_uffd.h>
  19
  20 /*
  21  * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
  22  * new flags, since they might collide with O_* ones. We want
  23  * to re-use O_* flags that couldn't possibly have a meaning
  24  * from userfaultfd, in order to leave a free define-space for
  25  * shared O_* flags.
  26  */
  27 #define UFFD_CLOEXEC O_CLOEXEC
  28 #define UFFD_NONBLOCK O_NONBLOCK
  29
  30 #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
  31 #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
  32
  33 extern int sysctl_unprivileged_userfaultfd;
  34
  35 extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
  36
  37 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
  38                             unsigned long src_start, unsigned long len,
  39                             bool *mmap_changing, __u64 mode);
  40 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
  41                               unsigned long dst_start,
  42                               unsigned long len,
  43                               bool *mmap_changing);
  44 extern int mwriteprotect_range(struct mm_struct *dst_mm,
  45                                unsigned long start, unsigned long len,
  46                                bool enable_wp, bool *mmap_changing);
  47
  48 /* mm helpers */
  49 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
  50                                         struct vm_userfaultfd_ctx vm_ctx)
  51 {
  52         return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
  53 }
  54
  55 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
  56 {
  57         return vma->vm_flags & VM_UFFD_MISSING;
  58 }
  59
  60 static inline bool userfaultfd_wp(struct vm_area_struct *vma)
  61 {
  62         return vma->vm_flags & VM_UFFD_WP;
  63 }
  64
  65 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
  66                                       pte_t pte)
  67 {
  68         return userfaultfd_wp(vma) && pte_uffd_wp(pte);
  69 }
  70
  71 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
  72                                            pmd_t pmd)
  73 {
  74         return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
  75 }
  76
  77 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
  78 {
  79         return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
  80 }
  81
  82 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
  83 extern void dup_userfaultfd_complete(struct list_head *);
  84
  85 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
  86                                     struct vm_userfaultfd_ctx *);
  87 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
  88                                         unsigned long from, unsigned long to,
  89                                         unsigned long len);
  90
  91 extern bool userfaultfd_remove(struct vm_area_struct *vma,
  92                                unsigned long start,
  93                                unsigned long end);
  94
  95 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
  96                                   unsigned long start, unsigned long end,
  97                                   struct list_head *uf);
  98 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
  99                                        struct list_head *uf);
 100
 101 #else /* CONFIG_USERFAULTFD */
 102
 103 /* mm helpers */
 104 static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
 105                                 unsigned long reason)
 106 {
 107         return VM_FAULT_SIGBUS;
 108 }
 109
 110 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
 111                                         struct vm_userfaultfd_ctx vm_ctx)
 112 {
 113         return true;
 114 }
 115
 116 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
 117 {
 118         return false;
 119 }
 120
 121 static inline bool userfaultfd_wp(struct vm_area_struct *vma)
 122 {
 123         return false;
 124 }
 125
 126 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
 127                                       pte_t pte)
 128 {
 129         return false;
 130 }
 131
 132 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
 133                                            pmd_t pmd)
 134 {
 135         return false;
 136 }
 137
 138
 139 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 140 {
 141         return false;
 142 }
 143
 144 static inline int dup_userfaultfd(struct vm_area_struct *vma,
 145                                   struct list_head *l)
 146 {
 147         return 0;
 148 }
 149
 150 static inline void dup_userfaultfd_complete(struct list_head *l)
 151 {
 152 }
 153
 154 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
 155                                            struct vm_userfaultfd_ctx *ctx)
 156 {
 157 }
 158
 159 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
 160                                                unsigned long from,
 161                                                unsigned long to,
 162                                                unsigned long len)
 163 {
 164 }
 165
 166 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
 167                                       unsigned long start,
 168                                       unsigned long end)
 169 {
 170         return true;
 171 }
 172
 173 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
 174                                          unsigned long start, unsigned long end,
 175                                          struct list_head *uf)
 176 {
 177         return 0;
 178 }
 179
 180 static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
 181                                               struct list_head *uf)
 182 {
 183 }
 184
 185 #endif /* CONFIG_USERFAULTFD */
 186
 187 #endif /* _LINUX_USERFAULTFD_K_H */