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 #include <linux/mm.h>
18 #include <asm-generic/pgtable_uffd.h>
19
20 /*
21 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
22 * new flags, since they might collide with O_* ones. We want
23 * to re-use O_* flags that couldn't possibly have a meaning
24 * from userfaultfd, in order to leave a free define-space for
25 * shared O_* flags.
26 */
27 #define UFFD_CLOEXEC O_CLOEXEC
28 #define UFFD_NONBLOCK O_NONBLOCK
29
30 #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
31 #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
32
33 extern int sysctl_unprivileged_userfaultfd;
34
35 extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
36
37 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
38 unsigned long src_start, unsigned long len,
39 bool *mmap_changing, __u64 mode);
40 extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
41 unsigned long dst_start,
42 unsigned long len,
43 bool *mmap_changing);
44 extern int mwriteprotect_range(struct mm_struct *dst_mm,
45 unsigned long start, unsigned long len,
46 bool enable_wp, bool *mmap_changing);
47
48 /* mm helpers */
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)49 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
50 struct vm_userfaultfd_ctx vm_ctx)
51 {
52 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
53 }
54
userfaultfd_missing(struct vm_area_struct * vma)55 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
56 {
57 return vma->vm_flags & VM_UFFD_MISSING;
58 }
59
userfaultfd_wp(struct vm_area_struct * vma)60 static inline bool userfaultfd_wp(struct vm_area_struct *vma)
61 {
62 return vma->vm_flags & VM_UFFD_WP;
63 }
64
userfaultfd_pte_wp(struct vm_area_struct * vma,pte_t pte)65 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
66 pte_t pte)
67 {
68 return userfaultfd_wp(vma) && pte_uffd_wp(pte);
69 }
70
userfaultfd_huge_pmd_wp(struct vm_area_struct * vma,pmd_t pmd)71 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
72 pmd_t pmd)
73 {
74 return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
75 }
76
userfaultfd_armed(struct vm_area_struct * vma)77 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
78 {
79 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
80 }
81
82 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
83 extern void dup_userfaultfd_complete(struct list_head *);
84
85 extern void mremap_userfaultfd_prep(struct vm_area_struct *,
86 struct vm_userfaultfd_ctx *);
87 extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
88 unsigned long from, unsigned long to,
89 unsigned long len);
90
91 extern bool userfaultfd_remove(struct vm_area_struct *vma,
92 unsigned long start,
93 unsigned long end);
94
95 extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
96 unsigned long start, unsigned long end,
97 struct list_head *uf);
98 extern void userfaultfd_unmap_complete(struct mm_struct *mm,
99 struct list_head *uf);
100
101 #else /* CONFIG_USERFAULTFD */
102
103 /* mm helpers */
handle_userfault(struct vm_fault * vmf,unsigned long reason)104 static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
105 unsigned long reason)
106 {
107 return VM_FAULT_SIGBUS;
108 }
109
is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct * vma,struct vm_userfaultfd_ctx vm_ctx)110 static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
111 struct vm_userfaultfd_ctx vm_ctx)
112 {
113 return true;
114 }
115
userfaultfd_missing(struct vm_area_struct * vma)116 static inline bool userfaultfd_missing(struct vm_area_struct *vma)
117 {
118 return false;
119 }
120
userfaultfd_wp(struct vm_area_struct * vma)121 static inline bool userfaultfd_wp(struct vm_area_struct *vma)
122 {
123 return false;
124 }
125
userfaultfd_pte_wp(struct vm_area_struct * vma,pte_t pte)126 static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
127 pte_t pte)
128 {
129 return false;
130 }
131
userfaultfd_huge_pmd_wp(struct vm_area_struct * vma,pmd_t pmd)132 static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
133 pmd_t pmd)
134 {
135 return false;
136 }
137
138
userfaultfd_armed(struct vm_area_struct * vma)139 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
140 {
141 return false;
142 }
143
dup_userfaultfd(struct vm_area_struct * vma,struct list_head * l)144 static inline int dup_userfaultfd(struct vm_area_struct *vma,
145 struct list_head *l)
146 {
147 return 0;
148 }
149
dup_userfaultfd_complete(struct list_head * l)150 static inline void dup_userfaultfd_complete(struct list_head *l)
151 {
152 }
153
mremap_userfaultfd_prep(struct vm_area_struct * vma,struct vm_userfaultfd_ctx * ctx)154 static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
155 struct vm_userfaultfd_ctx *ctx)
156 {
157 }
158
mremap_userfaultfd_complete(struct vm_userfaultfd_ctx * ctx,unsigned long from,unsigned long to,unsigned long len)159 static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
160 unsigned long from,
161 unsigned long to,
162 unsigned long len)
163 {
164 }
165
userfaultfd_remove(struct vm_area_struct * vma,unsigned long start,unsigned long end)166 static inline bool userfaultfd_remove(struct vm_area_struct *vma,
167 unsigned long start,
168 unsigned long end)
169 {
170 return true;
171 }
172
userfaultfd_unmap_prep(struct vm_area_struct * vma,unsigned long start,unsigned long end,struct list_head * uf)173 static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
174 unsigned long start, unsigned long end,
175 struct list_head *uf)
176 {
177 return 0;
178 }
179
userfaultfd_unmap_complete(struct mm_struct * mm,struct list_head * uf)180 static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
181 struct list_head *uf)
182 {
183 }
184
185 #endif /* CONFIG_USERFAULTFD */
186
187 #endif /* _LINUX_USERFAULTFD_K_H */
188