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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,
35 bool *mmap_changing);
36extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
37 unsigned long dst_start,
38 unsigned long len,
39 bool *mmap_changing);
40
41/* mm helpers */
42static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
43 struct vm_userfaultfd_ctx vm_ctx)
44{
45 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
46}
47
48static inline bool userfaultfd_missing(struct vm_area_struct *vma)
49{
50 return vma->vm_flags & VM_UFFD_MISSING;
51}
52
53static inline bool userfaultfd_armed(struct vm_area_struct *vma)
54{
55 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
56}
57
58extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
59extern void dup_userfaultfd_complete(struct list_head *);
60
61extern void mremap_userfaultfd_prep(struct vm_area_struct *,
62 struct vm_userfaultfd_ctx *);
63extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
64 unsigned long from, unsigned long to,
65 unsigned long len);
66
67extern bool userfaultfd_remove(struct vm_area_struct *vma,
68 unsigned long start,
69 unsigned long end);
70
71extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
72 unsigned long start, unsigned long end,
73 struct list_head *uf);
74extern void userfaultfd_unmap_complete(struct mm_struct *mm,
75 struct list_head *uf);
76
77#else /* CONFIG_USERFAULTFD */
78
79/* mm helpers */
80static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
81{
82 return VM_FAULT_SIGBUS;
83}
84
85static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
86 struct vm_userfaultfd_ctx vm_ctx)
87{
88 return true;
89}
90
91static inline bool userfaultfd_missing(struct vm_area_struct *vma)
92{
93 return false;
94}
95
96static inline bool userfaultfd_armed(struct vm_area_struct *vma)
97{
98 return false;
99}
100
101static inline int dup_userfaultfd(struct vm_area_struct *vma,
102 struct list_head *l)
103{
104 return 0;
105}
106
107static inline void dup_userfaultfd_complete(struct list_head *l)
108{
109}
110
111static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
112 struct vm_userfaultfd_ctx *ctx)
113{
114}
115
116static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
117 unsigned long from,
118 unsigned long to,
119 unsigned long len)
120{
121}
122
123static inline bool userfaultfd_remove(struct vm_area_struct *vma,
124 unsigned long start,
125 unsigned long end)
126{
127 return true;
128}
129
130static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
131 unsigned long start, unsigned long end,
132 struct list_head *uf)
133{
134 return 0;
135}
136
137static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
138 struct list_head *uf)
139{
140}
141
142#endif /* CONFIG_USERFAULTFD */
143
144#endif /* _LINUX_USERFAULTFD_K_H */