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