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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 vm_fault_t 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 vm_fault_t handle_userfault(struct vm_fault *vmf,
81 unsigned long reason)
82{
83 return VM_FAULT_SIGBUS;
84}
85
86static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
87 struct vm_userfaultfd_ctx vm_ctx)
88{
89 return true;
90}
91
92static inline bool userfaultfd_missing(struct vm_area_struct *vma)
93{
94 return false;
95}
96
97static inline bool userfaultfd_armed(struct vm_area_struct *vma)
98{
99 return false;
100}
101
102static inline int dup_userfaultfd(struct vm_area_struct *vma,
103 struct list_head *l)
104{
105 return 0;
106}
107
108static inline void dup_userfaultfd_complete(struct list_head *l)
109{
110}
111
112static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
113 struct vm_userfaultfd_ctx *ctx)
114{
115}
116
117static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
118 unsigned long from,
119 unsigned long to,
120 unsigned long len)
121{
122}
123
124static inline bool userfaultfd_remove(struct vm_area_struct *vma,
125 unsigned long start,
126 unsigned long end)
127{
128 return true;
129}
130
131static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
132 unsigned long start, unsigned long end,
133 struct list_head *uf)
134{
135 return 0;
136}
137
138static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
139 struct list_head *uf)
140{
141}
142
143#endif /* CONFIG_USERFAULTFD */
144
145#endif /* _LINUX_USERFAULTFD_K_H */