Commit | Line | Data |
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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 | 17 | #include <linux/mm.h> |
1db9dbc2 PX |
18 | #include <linux/swap.h> |
19 | #include <linux/swapops.h> | |
55adf4de | 20 | #include <asm-generic/pgtable_uffd.h> |
932b18e0 | 21 | |
7677f7fd AR |
22 | /* The set of all possible UFFD-related VM flags. */ |
23 | #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR) | |
24 | ||
932b18e0 AA |
25 | /* |
26 | * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining | |
27 | * new flags, since they might collide with O_* ones. We want | |
28 | * to re-use O_* flags that couldn't possibly have a meaning | |
29 | * from userfaultfd, in order to leave a free define-space for | |
30 | * shared O_* flags. | |
31 | */ | |
32 | #define UFFD_CLOEXEC O_CLOEXEC | |
33 | #define UFFD_NONBLOCK O_NONBLOCK | |
34 | ||
35 | #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) | |
36 | #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) | |
37 | ||
cefdca0a PX |
38 | extern int sysctl_unprivileged_userfaultfd; |
39 | ||
2b740303 | 40 | extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); |
932b18e0 | 41 | |
f6191471 AR |
42 | /* |
43 | * The mode of operation for __mcopy_atomic and its helpers. | |
44 | * | |
45 | * This is almost an implementation detail (mcopy_atomic below doesn't take this | |
46 | * as a parameter), but it's exposed here because memory-kind-specific | |
47 | * implementations (e.g. hugetlbfs) need to know the mode of operation. | |
48 | */ | |
49 | enum mcopy_atomic_mode { | |
50 | /* A normal copy_from_user into the destination range. */ | |
51 | MCOPY_ATOMIC_NORMAL, | |
52 | /* Don't copy; map the destination range to the zero page. */ | |
53 | MCOPY_ATOMIC_ZEROPAGE, | |
54 | /* Just install pte(s) with the existing page(s) in the page cache. */ | |
55 | MCOPY_ATOMIC_CONTINUE, | |
56 | }; | |
57 | ||
7d64ae3a AR |
58 | extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, |
59 | struct vm_area_struct *dst_vma, | |
60 | unsigned long dst_addr, struct page *page, | |
61 | bool newly_allocated, bool wp_copy); | |
62 | ||
c1a4de99 | 63 | extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, |
df2cc96e | 64 | unsigned long src_start, unsigned long len, |
a759a909 | 65 | atomic_t *mmap_changing, __u64 mode); |
c1a4de99 AA |
66 | extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, |
67 | unsigned long dst_start, | |
df2cc96e | 68 | unsigned long len, |
a759a909 | 69 | atomic_t *mmap_changing); |
f6191471 | 70 | extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start, |
a759a909 | 71 | unsigned long len, atomic_t *mmap_changing); |
ffd05793 SL |
72 | extern int mwriteprotect_range(struct mm_struct *dst_mm, |
73 | unsigned long start, unsigned long len, | |
a759a909 | 74 | bool enable_wp, atomic_t *mmap_changing); |
c1a4de99 | 75 | |
932b18e0 AA |
76 | /* mm helpers */ |
77 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
78 | struct vm_userfaultfd_ctx vm_ctx) | |
79 | { | |
80 | return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; | |
81 | } | |
82 | ||
c1991e07 | 83 | /* |
0d9cadab AR |
84 | * Never enable huge pmd sharing on some uffd registered vmas: |
85 | * | |
86 | * - VM_UFFD_WP VMAs, because write protect information is per pgtable entry. | |
87 | * | |
88 | * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for | |
89 | * VMAs which share huge pmds. (If you have two mappings to the same | |
90 | * underlying pages, and fault in the non-UFFD-registered one with a write, | |
91 | * with huge pmd sharing this would *also* setup the second UFFD-registered | |
92 | * mapping, and we'd not get minor faults.) | |
c1991e07 PX |
93 | */ |
94 | static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) | |
95 | { | |
0d9cadab | 96 | return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); |
c1991e07 PX |
97 | } |
98 | ||
9c28a205 PX |
99 | /* |
100 | * Don't do fault around for either WP or MINOR registered uffd range. For | |
101 | * MINOR registered range, fault around will be a total disaster and ptes can | |
102 | * be installed without notifications; for WP it should mostly be fine as long | |
103 | * as the fault around checks for pte_none() before the installation, however | |
104 | * to be super safe we just forbid it. | |
105 | */ | |
106 | static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) | |
107 | { | |
108 | return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); | |
109 | } | |
110 | ||
932b18e0 AA |
111 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) |
112 | { | |
113 | return vma->vm_flags & VM_UFFD_MISSING; | |
114 | } | |
115 | ||
1df319e0 SL |
116 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
117 | { | |
118 | return vma->vm_flags & VM_UFFD_WP; | |
119 | } | |
120 | ||
7677f7fd AR |
121 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
122 | { | |
123 | return vma->vm_flags & VM_UFFD_MINOR; | |
124 | } | |
125 | ||
55adf4de AA |
126 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
127 | pte_t pte) | |
128 | { | |
129 | return userfaultfd_wp(vma) && pte_uffd_wp(pte); | |
130 | } | |
131 | ||
132 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
133 | pmd_t pmd) | |
134 | { | |
135 | return userfaultfd_wp(vma) && pmd_uffd_wp(pmd); | |
136 | } | |
137 | ||
932b18e0 AA |
138 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
139 | { | |
7677f7fd | 140 | return vma->vm_flags & __VM_UFFD_FLAGS; |
932b18e0 AA |
141 | } |
142 | ||
893e26e6 PE |
143 | extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); |
144 | extern void dup_userfaultfd_complete(struct list_head *); | |
145 | ||
72f87654 PE |
146 | extern void mremap_userfaultfd_prep(struct vm_area_struct *, |
147 | struct vm_userfaultfd_ctx *); | |
90794bf1 | 148 | extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, |
72f87654 PE |
149 | unsigned long from, unsigned long to, |
150 | unsigned long len); | |
151 | ||
70ccb92f | 152 | extern bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
153 | unsigned long start, |
154 | unsigned long end); | |
05ce7724 | 155 | |
897ab3e0 MR |
156 | extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, |
157 | unsigned long start, unsigned long end, | |
158 | struct list_head *uf); | |
159 | extern void userfaultfd_unmap_complete(struct mm_struct *mm, | |
160 | struct list_head *uf); | |
161 | ||
932b18e0 AA |
162 | #else /* CONFIG_USERFAULTFD */ |
163 | ||
164 | /* mm helpers */ | |
2b740303 SJ |
165 | static inline vm_fault_t handle_userfault(struct vm_fault *vmf, |
166 | unsigned long reason) | |
932b18e0 AA |
167 | { |
168 | return VM_FAULT_SIGBUS; | |
169 | } | |
170 | ||
171 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
172 | struct vm_userfaultfd_ctx vm_ctx) | |
173 | { | |
174 | return true; | |
175 | } | |
176 | ||
177 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) | |
178 | { | |
179 | return false; | |
180 | } | |
181 | ||
1df319e0 SL |
182 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
183 | { | |
184 | return false; | |
185 | } | |
186 | ||
7677f7fd AR |
187 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
188 | { | |
189 | return false; | |
190 | } | |
191 | ||
55adf4de AA |
192 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
193 | pte_t pte) | |
194 | { | |
195 | return false; | |
196 | } | |
197 | ||
198 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
199 | pmd_t pmd) | |
200 | { | |
201 | return false; | |
202 | } | |
203 | ||
204 | ||
932b18e0 AA |
205 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
206 | { | |
207 | return false; | |
208 | } | |
209 | ||
893e26e6 PE |
210 | static inline int dup_userfaultfd(struct vm_area_struct *vma, |
211 | struct list_head *l) | |
212 | { | |
213 | return 0; | |
214 | } | |
215 | ||
216 | static inline void dup_userfaultfd_complete(struct list_head *l) | |
217 | { | |
218 | } | |
219 | ||
72f87654 PE |
220 | static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, |
221 | struct vm_userfaultfd_ctx *ctx) | |
222 | { | |
223 | } | |
224 | ||
90794bf1 | 225 | static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, |
72f87654 PE |
226 | unsigned long from, |
227 | unsigned long to, | |
228 | unsigned long len) | |
229 | { | |
230 | } | |
05ce7724 | 231 | |
70ccb92f | 232 | static inline bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
233 | unsigned long start, |
234 | unsigned long end) | |
05ce7724 | 235 | { |
70ccb92f | 236 | return true; |
05ce7724 | 237 | } |
897ab3e0 MR |
238 | |
239 | static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, | |
240 | unsigned long start, unsigned long end, | |
241 | struct list_head *uf) | |
242 | { | |
243 | return 0; | |
244 | } | |
245 | ||
246 | static inline void userfaultfd_unmap_complete(struct mm_struct *mm, | |
247 | struct list_head *uf) | |
248 | { | |
249 | } | |
ca49ca71 | 250 | |
9c28a205 PX |
251 | static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) |
252 | { | |
253 | return false; | |
254 | } | |
255 | ||
932b18e0 AA |
256 | #endif /* CONFIG_USERFAULTFD */ |
257 | ||
1db9dbc2 PX |
258 | static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) |
259 | { | |
260 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
261 | return is_pte_marker_entry(entry) && | |
262 | (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); | |
263 | #else | |
264 | return false; | |
265 | #endif | |
266 | } | |
267 | ||
268 | static inline bool pte_marker_uffd_wp(pte_t pte) | |
269 | { | |
270 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
271 | swp_entry_t entry; | |
272 | ||
273 | if (!is_swap_pte(pte)) | |
274 | return false; | |
275 | ||
276 | entry = pte_to_swp_entry(pte); | |
277 | ||
278 | return pte_marker_entry_uffd_wp(entry); | |
279 | #else | |
280 | return false; | |
281 | #endif | |
282 | } | |
283 | ||
284 | /* | |
285 | * Returns true if this is a swap pte and was uffd-wp wr-protected in either | |
286 | * forms (pte marker or a normal swap pte), false otherwise. | |
287 | */ | |
288 | static inline bool pte_swp_uffd_wp_any(pte_t pte) | |
289 | { | |
290 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
291 | if (!is_swap_pte(pte)) | |
292 | return false; | |
293 | ||
294 | if (pte_swp_uffd_wp(pte)) | |
295 | return true; | |
296 | ||
297 | if (pte_marker_uffd_wp(pte)) | |
298 | return true; | |
299 | #endif | |
300 | return false; | |
301 | } | |
302 | ||
932b18e0 | 303 | #endif /* _LINUX_USERFAULTFD_K_H */ |