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 sysctl_unprivileged_userfaultfd;
32
33 extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
34
35 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
36 unsigned long src_start, unsigned long len,
37 bool *mmap_changing);
38 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
39 unsigned long dst_start,
40 unsigned long len,
41 bool *mmap_changing);
42
43 /* mm helpers */
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)44 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
45 struct vm_userfaultfd_ctx vm_ctx)
46 {
47 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
48 }
49
userfaultfd_missing(struct vm_area_struct * vma)50 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
51 {
52 return vma->vm_flags & VM_UFFD_MISSING;
53 }
54
userfaultfd_armed(struct vm_area_struct * vma)55 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
56 {
57 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
58 }
59
60 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
61 extern void dup_userfaultfd_complete(struct list_head *);
62
63 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
64 struct vm_userfaultfd_ctx *);
65 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
66 unsigned long from, unsigned long to,
67 unsigned long len);
68
69 extern bool userfaultfd_remove(struct vm_area_struct *vma,
70 unsigned long start,
71 unsigned long end);
72
73 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
74 unsigned long start, unsigned long end,
75 struct list_head *uf);
76 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
77 struct list_head *uf);
78
79 #else /* CONFIG_USERFAULTFD */
80
81 /* mm helpers */
handle_userfault(struct vm_fault * vmf,unsigned long reason)82 static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
83 unsigned long reason)
84 {
85 return VM_FAULT_SIGBUS;
86 }
87
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)88 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
89 struct vm_userfaultfd_ctx vm_ctx)
90 {
91 return true;
92 }
93
userfaultfd_missing(struct vm_area_struct * vma)94 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
95 {
96 return false;
97 }
98
userfaultfd_armed(struct vm_area_struct * vma)99 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
100 {
101 return false;
102 }
103
dup_userfaultfd(struct vm_area_struct * vma,struct list_head * l)104 static inline int dup_userfaultfd(struct vm_area_struct *vma,
105 struct list_head *l)
106 {
107 return 0;
108 }
109
dup_userfaultfd_complete(struct list_head * l)110 static inline void dup_userfaultfd_complete(struct list_head *l)
111 {
112 }
113
mremap_userfaultfd_prep(struct vm_area_struct * vma,struct vm_userfaultfd_ctx * ctx)114 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
115 struct vm_userfaultfd_ctx *ctx)
116 {
117 }
118
mremap_userfaultfd_complete(struct vm_userfaultfd_ctx * ctx,unsigned long from,unsigned long to,unsigned long len)119 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
120 unsigned long from,
121 unsigned long to,
122 unsigned long len)
123 {
124 }
125
userfaultfd_remove(struct vm_area_struct * vma,unsigned long start,unsigned long end)126 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
127 unsigned long start,
128 unsigned long end)
129 {
130 return true;
131 }
132
userfaultfd_unmap_prep(struct vm_area_struct * vma,unsigned long start,unsigned long end,struct list_head * uf)133 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
134 unsigned long start, unsigned long end,
135 struct list_head *uf)
136 {
137 return 0;
138 }
139
userfaultfd_unmap_complete(struct mm_struct * mm,struct list_head * uf)140 static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
141 struct list_head *uf)
142 {
143 }
144
145 #endif /* CONFIG_USERFAULTFD */
146
147 #endif /* _LINUX_USERFAULTFD_K_H */
148