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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
932b18e0 AA |
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> | |
55adf4de AA |
17 | #include <linux/mm.h> |
18 | #include <asm-generic/pgtable_uffd.h> | |
932b18e0 | 19 | |
7677f7fd AR |
20 | /* The set of all possible UFFD-related VM flags. */ |
21 | #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR) | |
22 | ||
932b18e0 AA |
23 | /* |
24 | * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining | |
25 | * new flags, since they might collide with O_* ones. We want | |
26 | * to re-use O_* flags that couldn't possibly have a meaning | |
27 | * from userfaultfd, in order to leave a free define-space for | |
28 | * shared O_* flags. | |
29 | */ | |
30 | #define UFFD_CLOEXEC O_CLOEXEC | |
31 | #define UFFD_NONBLOCK O_NONBLOCK | |
32 | ||
33 | #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) | |
34 | #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) | |
35 | ||
cefdca0a PX |
36 | extern int sysctl_unprivileged_userfaultfd; |
37 | ||
2b740303 | 38 | extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); |
932b18e0 | 39 | |
f6191471 AR |
40 | /* |
41 | * The mode of operation for __mcopy_atomic and its helpers. | |
42 | * | |
43 | * This is almost an implementation detail (mcopy_atomic below doesn't take this | |
44 | * as a parameter), but it's exposed here because memory-kind-specific | |
45 | * implementations (e.g. hugetlbfs) need to know the mode of operation. | |
46 | */ | |
47 | enum mcopy_atomic_mode { | |
48 | /* A normal copy_from_user into the destination range. */ | |
49 | MCOPY_ATOMIC_NORMAL, | |
50 | /* Don't copy; map the destination range to the zero page. */ | |
51 | MCOPY_ATOMIC_ZEROPAGE, | |
52 | /* Just install pte(s) with the existing page(s) in the page cache. */ | |
53 | MCOPY_ATOMIC_CONTINUE, | |
54 | }; | |
55 | ||
7d64ae3a AR |
56 | extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, |
57 | struct vm_area_struct *dst_vma, | |
58 | unsigned long dst_addr, struct page *page, | |
59 | bool newly_allocated, bool wp_copy); | |
60 | ||
c1a4de99 | 61 | extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, |
df2cc96e | 62 | unsigned long src_start, unsigned long len, |
72981e0e | 63 | bool *mmap_changing, __u64 mode); |
c1a4de99 AA |
64 | extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, |
65 | unsigned long dst_start, | |
df2cc96e MR |
66 | unsigned long len, |
67 | bool *mmap_changing); | |
f6191471 AR |
68 | extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start, |
69 | unsigned long len, bool *mmap_changing); | |
ffd05793 SL |
70 | extern int mwriteprotect_range(struct mm_struct *dst_mm, |
71 | unsigned long start, unsigned long len, | |
72 | bool enable_wp, bool *mmap_changing); | |
c1a4de99 | 73 | |
932b18e0 AA |
74 | /* mm helpers */ |
75 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
76 | struct vm_userfaultfd_ctx vm_ctx) | |
77 | { | |
78 | return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; | |
79 | } | |
80 | ||
c1991e07 | 81 | /* |
0d9cadab AR |
82 | * Never enable huge pmd sharing on some uffd registered vmas: |
83 | * | |
84 | * - VM_UFFD_WP VMAs, because write protect information is per pgtable entry. | |
85 | * | |
86 | * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for | |
87 | * VMAs which share huge pmds. (If you have two mappings to the same | |
88 | * underlying pages, and fault in the non-UFFD-registered one with a write, | |
89 | * with huge pmd sharing this would *also* setup the second UFFD-registered | |
90 | * mapping, and we'd not get minor faults.) | |
c1991e07 PX |
91 | */ |
92 | static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) | |
93 | { | |
0d9cadab | 94 | return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); |
c1991e07 PX |
95 | } |
96 | ||
932b18e0 AA |
97 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) |
98 | { | |
99 | return vma->vm_flags & VM_UFFD_MISSING; | |
100 | } | |
101 | ||
1df319e0 SL |
102 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
103 | { | |
104 | return vma->vm_flags & VM_UFFD_WP; | |
105 | } | |
106 | ||
7677f7fd AR |
107 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
108 | { | |
109 | return vma->vm_flags & VM_UFFD_MINOR; | |
110 | } | |
111 | ||
55adf4de AA |
112 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
113 | pte_t pte) | |
114 | { | |
115 | return userfaultfd_wp(vma) && pte_uffd_wp(pte); | |
116 | } | |
117 | ||
118 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
119 | pmd_t pmd) | |
120 | { | |
121 | return userfaultfd_wp(vma) && pmd_uffd_wp(pmd); | |
122 | } | |
123 | ||
932b18e0 AA |
124 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
125 | { | |
7677f7fd | 126 | return vma->vm_flags & __VM_UFFD_FLAGS; |
932b18e0 AA |
127 | } |
128 | ||
893e26e6 PE |
129 | extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); |
130 | extern void dup_userfaultfd_complete(struct list_head *); | |
131 | ||
72f87654 PE |
132 | extern void mremap_userfaultfd_prep(struct vm_area_struct *, |
133 | struct vm_userfaultfd_ctx *); | |
90794bf1 | 134 | extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, |
72f87654 PE |
135 | unsigned long from, unsigned long to, |
136 | unsigned long len); | |
137 | ||
70ccb92f | 138 | extern bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
139 | unsigned long start, |
140 | unsigned long end); | |
05ce7724 | 141 | |
897ab3e0 MR |
142 | extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, |
143 | unsigned long start, unsigned long end, | |
144 | struct list_head *uf); | |
145 | extern void userfaultfd_unmap_complete(struct mm_struct *mm, | |
146 | struct list_head *uf); | |
147 | ||
932b18e0 AA |
148 | #else /* CONFIG_USERFAULTFD */ |
149 | ||
150 | /* mm helpers */ | |
2b740303 SJ |
151 | static inline vm_fault_t handle_userfault(struct vm_fault *vmf, |
152 | unsigned long reason) | |
932b18e0 AA |
153 | { |
154 | return VM_FAULT_SIGBUS; | |
155 | } | |
156 | ||
157 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
158 | struct vm_userfaultfd_ctx vm_ctx) | |
159 | { | |
160 | return true; | |
161 | } | |
162 | ||
163 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) | |
164 | { | |
165 | return false; | |
166 | } | |
167 | ||
1df319e0 SL |
168 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
169 | { | |
170 | return false; | |
171 | } | |
172 | ||
7677f7fd AR |
173 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
174 | { | |
175 | return false; | |
176 | } | |
177 | ||
55adf4de AA |
178 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
179 | pte_t pte) | |
180 | { | |
181 | return false; | |
182 | } | |
183 | ||
184 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
185 | pmd_t pmd) | |
186 | { | |
187 | return false; | |
188 | } | |
189 | ||
190 | ||
932b18e0 AA |
191 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
192 | { | |
193 | return false; | |
194 | } | |
195 | ||
893e26e6 PE |
196 | static inline int dup_userfaultfd(struct vm_area_struct *vma, |
197 | struct list_head *l) | |
198 | { | |
199 | return 0; | |
200 | } | |
201 | ||
202 | static inline void dup_userfaultfd_complete(struct list_head *l) | |
203 | { | |
204 | } | |
205 | ||
72f87654 PE |
206 | static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, |
207 | struct vm_userfaultfd_ctx *ctx) | |
208 | { | |
209 | } | |
210 | ||
90794bf1 | 211 | static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, |
72f87654 PE |
212 | unsigned long from, |
213 | unsigned long to, | |
214 | unsigned long len) | |
215 | { | |
216 | } | |
05ce7724 | 217 | |
70ccb92f | 218 | static inline bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
219 | unsigned long start, |
220 | unsigned long end) | |
05ce7724 | 221 | { |
70ccb92f | 222 | return true; |
05ce7724 | 223 | } |
897ab3e0 MR |
224 | |
225 | static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, | |
226 | unsigned long start, unsigned long end, | |
227 | struct list_head *uf) | |
228 | { | |
229 | return 0; | |
230 | } | |
231 | ||
232 | static inline void userfaultfd_unmap_complete(struct mm_struct *mm, | |
233 | struct list_head *uf) | |
234 | { | |
235 | } | |
ca49ca71 | 236 | |
932b18e0 AA |
237 | #endif /* CONFIG_USERFAULTFD */ |
238 | ||
239 | #endif /* _LINUX_USERFAULTFD_K_H */ |