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 */
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)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
userfaultfd_missing(struct vm_area_struct * vma)46 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
47 {
48 return vma->vm_flags & VM_UFFD_MISSING;
49 }
50
userfaultfd_armed(struct vm_area_struct * vma)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 */
handle_userfault(struct vm_fault * vmf,unsigned long reason)78 static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
79 {
80 return VM_FAULT_SIGBUS;
81 }
82
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)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
userfaultfd_missing(struct vm_area_struct * vma)89 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
90 {
91 return false;
92 }
93
userfaultfd_armed(struct vm_area_struct * vma)94 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
95 {
96 return false;
97 }
98
dup_userfaultfd(struct vm_area_struct * vma,struct list_head * l)99 static inline int dup_userfaultfd(struct vm_area_struct *vma,
100 struct list_head *l)
101 {
102 return 0;
103 }
104
dup_userfaultfd_complete(struct list_head * l)105 static inline void dup_userfaultfd_complete(struct list_head *l)
106 {
107 }
108
mremap_userfaultfd_prep(struct vm_area_struct * vma,struct vm_userfaultfd_ctx * ctx)109 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
110 struct vm_userfaultfd_ctx *ctx)
111 {
112 }
113
mremap_userfaultfd_complete(struct vm_userfaultfd_ctx * ctx,unsigned long from,unsigned long to,unsigned long len)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
userfaultfd_remove(struct vm_area_struct * vma,unsigned long start,unsigned long end)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
userfaultfd_unmap_prep(struct vm_area_struct * vma,unsigned long start,unsigned long end,struct list_head * uf)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
userfaultfd_unmap_complete(struct mm_struct * mm,struct list_head * uf)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 */
143