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 vm_fault_t 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 bool *mmap_changing);
36 extern 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 */
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)42 static 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
userfaultfd_missing(struct vm_area_struct * vma)48 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
49 {
50 return vma->vm_flags & VM_UFFD_MISSING;
51 }
52
userfaultfd_armed(struct vm_area_struct * vma)53 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
54 {
55 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
56 }
57
58 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
59 extern void dup_userfaultfd_complete(struct list_head *);
60
61 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
62 struct vm_userfaultfd_ctx *);
63 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
64 unsigned long from, unsigned long to,
65 unsigned long len);
66
67 extern bool userfaultfd_remove(struct vm_area_struct *vma,
68 unsigned long start,
69 unsigned long end);
70
71 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
72 unsigned long start, unsigned long end,
73 struct list_head *uf);
74 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
75 struct list_head *uf);
76
77 #else /* CONFIG_USERFAULTFD */
78
79 /* mm helpers */
handle_userfault(struct vm_fault * vmf,unsigned long reason)80 static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
81 unsigned long reason)
82 {
83 return VM_FAULT_SIGBUS;
84 }
85
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)86 static 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
userfaultfd_missing(struct vm_area_struct * vma)92 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
93 {
94 return false;
95 }
96
userfaultfd_armed(struct vm_area_struct * vma)97 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
98 {
99 return false;
100 }
101
dup_userfaultfd(struct vm_area_struct * vma,struct list_head * l)102 static inline int dup_userfaultfd(struct vm_area_struct *vma,
103 struct list_head *l)
104 {
105 return 0;
106 }
107
dup_userfaultfd_complete(struct list_head * l)108 static inline void dup_userfaultfd_complete(struct list_head *l)
109 {
110 }
111
mremap_userfaultfd_prep(struct vm_area_struct * vma,struct vm_userfaultfd_ctx * ctx)112 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
113 struct vm_userfaultfd_ctx *ctx)
114 {
115 }
116
mremap_userfaultfd_complete(struct vm_userfaultfd_ctx * ctx,unsigned long from,unsigned long to,unsigned long len)117 static 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
userfaultfd_remove(struct vm_area_struct * vma,unsigned long start,unsigned long end)124 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
125 unsigned long start,
126 unsigned long end)
127 {
128 return true;
129 }
130
userfaultfd_unmap_prep(struct vm_area_struct * vma,unsigned long start,unsigned long end,struct list_head * uf)131 static 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
userfaultfd_unmap_complete(struct mm_struct * mm,struct list_head * uf)138 static 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 */
146