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> |
b1f9e876 | 21 | #include <linux/hugetlb_inline.h> |
932b18e0 | 22 | |
7677f7fd AR |
23 | /* The set of all possible UFFD-related VM flags. */ |
24 | #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR) | |
25 | ||
932b18e0 AA |
26 | /* |
27 | * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining | |
28 | * new flags, since they might collide with O_* ones. We want | |
29 | * to re-use O_* flags that couldn't possibly have a meaning | |
30 | * from userfaultfd, in order to leave a free define-space for | |
31 | * shared O_* flags. | |
32 | */ | |
33 | #define UFFD_CLOEXEC O_CLOEXEC | |
34 | #define UFFD_NONBLOCK O_NONBLOCK | |
35 | ||
36 | #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) | |
37 | #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) | |
38 | ||
cefdca0a PX |
39 | extern int sysctl_unprivileged_userfaultfd; |
40 | ||
2b740303 | 41 | extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); |
932b18e0 | 42 | |
f6191471 AR |
43 | /* |
44 | * The mode of operation for __mcopy_atomic and its helpers. | |
45 | * | |
46 | * This is almost an implementation detail (mcopy_atomic below doesn't take this | |
47 | * as a parameter), but it's exposed here because memory-kind-specific | |
48 | * implementations (e.g. hugetlbfs) need to know the mode of operation. | |
49 | */ | |
50 | enum mcopy_atomic_mode { | |
51 | /* A normal copy_from_user into the destination range. */ | |
52 | MCOPY_ATOMIC_NORMAL, | |
53 | /* Don't copy; map the destination range to the zero page. */ | |
54 | MCOPY_ATOMIC_ZEROPAGE, | |
55 | /* Just install pte(s) with the existing page(s) in the page cache. */ | |
56 | MCOPY_ATOMIC_CONTINUE, | |
57 | }; | |
58 | ||
7d64ae3a AR |
59 | extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, |
60 | struct vm_area_struct *dst_vma, | |
61 | unsigned long dst_addr, struct page *page, | |
62 | bool newly_allocated, bool wp_copy); | |
63 | ||
c1a4de99 | 64 | extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, |
df2cc96e | 65 | unsigned long src_start, unsigned long len, |
a759a909 | 66 | atomic_t *mmap_changing, __u64 mode); |
c1a4de99 AA |
67 | extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, |
68 | unsigned long dst_start, | |
df2cc96e | 69 | unsigned long len, |
a759a909 | 70 | atomic_t *mmap_changing); |
f6191471 | 71 | extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start, |
a759a909 | 72 | unsigned long len, atomic_t *mmap_changing); |
ffd05793 SL |
73 | extern int mwriteprotect_range(struct mm_struct *dst_mm, |
74 | unsigned long start, unsigned long len, | |
a759a909 | 75 | bool enable_wp, atomic_t *mmap_changing); |
f369b07c PX |
76 | extern void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma, |
77 | unsigned long start, unsigned long len, bool enable_wp); | |
c1a4de99 | 78 | |
932b18e0 AA |
79 | /* mm helpers */ |
80 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
81 | struct vm_userfaultfd_ctx vm_ctx) | |
82 | { | |
83 | return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; | |
84 | } | |
85 | ||
c1991e07 | 86 | /* |
0d9cadab AR |
87 | * Never enable huge pmd sharing on some uffd registered vmas: |
88 | * | |
89 | * - VM_UFFD_WP VMAs, because write protect information is per pgtable entry. | |
90 | * | |
91 | * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for | |
92 | * VMAs which share huge pmds. (If you have two mappings to the same | |
93 | * underlying pages, and fault in the non-UFFD-registered one with a write, | |
94 | * with huge pmd sharing this would *also* setup the second UFFD-registered | |
95 | * mapping, and we'd not get minor faults.) | |
c1991e07 PX |
96 | */ |
97 | static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) | |
98 | { | |
0d9cadab | 99 | return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); |
c1991e07 PX |
100 | } |
101 | ||
9c28a205 PX |
102 | /* |
103 | * Don't do fault around for either WP or MINOR registered uffd range. For | |
104 | * MINOR registered range, fault around will be a total disaster and ptes can | |
105 | * be installed without notifications; for WP it should mostly be fine as long | |
106 | * as the fault around checks for pte_none() before the installation, however | |
107 | * to be super safe we just forbid it. | |
108 | */ | |
109 | static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) | |
110 | { | |
111 | return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR); | |
112 | } | |
113 | ||
932b18e0 AA |
114 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) |
115 | { | |
116 | return vma->vm_flags & VM_UFFD_MISSING; | |
117 | } | |
118 | ||
1df319e0 SL |
119 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
120 | { | |
121 | return vma->vm_flags & VM_UFFD_WP; | |
122 | } | |
123 | ||
7677f7fd AR |
124 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
125 | { | |
126 | return vma->vm_flags & VM_UFFD_MINOR; | |
127 | } | |
128 | ||
55adf4de AA |
129 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
130 | pte_t pte) | |
131 | { | |
132 | return userfaultfd_wp(vma) && pte_uffd_wp(pte); | |
133 | } | |
134 | ||
135 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
136 | pmd_t pmd) | |
137 | { | |
138 | return userfaultfd_wp(vma) && pmd_uffd_wp(pmd); | |
139 | } | |
140 | ||
932b18e0 AA |
141 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
142 | { | |
7677f7fd | 143 | return vma->vm_flags & __VM_UFFD_FLAGS; |
932b18e0 AA |
144 | } |
145 | ||
b1f9e876 PX |
146 | static inline bool vma_can_userfault(struct vm_area_struct *vma, |
147 | unsigned long vm_flags) | |
148 | { | |
67eae54b PX |
149 | if ((vm_flags & VM_UFFD_MINOR) && |
150 | (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma))) | |
151 | return false; | |
b1f9e876 PX |
152 | #ifndef CONFIG_PTE_MARKER_UFFD_WP |
153 | /* | |
154 | * If user requested uffd-wp but not enabled pte markers for | |
155 | * uffd-wp, then shmem & hugetlbfs are not supported but only | |
156 | * anonymous. | |
157 | */ | |
158 | if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) | |
159 | return false; | |
160 | #endif | |
161 | return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || | |
162 | vma_is_shmem(vma); | |
163 | } | |
164 | ||
893e26e6 PE |
165 | extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); |
166 | extern void dup_userfaultfd_complete(struct list_head *); | |
167 | ||
72f87654 PE |
168 | extern void mremap_userfaultfd_prep(struct vm_area_struct *, |
169 | struct vm_userfaultfd_ctx *); | |
90794bf1 | 170 | extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *, |
72f87654 PE |
171 | unsigned long from, unsigned long to, |
172 | unsigned long len); | |
173 | ||
70ccb92f | 174 | extern bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
175 | unsigned long start, |
176 | unsigned long end); | |
05ce7724 | 177 | |
69dbe6da LH |
178 | extern int userfaultfd_unmap_prep(struct mm_struct *mm, unsigned long start, |
179 | unsigned long end, struct list_head *uf); | |
897ab3e0 MR |
180 | extern void userfaultfd_unmap_complete(struct mm_struct *mm, |
181 | struct list_head *uf); | |
182 | ||
932b18e0 AA |
183 | #else /* CONFIG_USERFAULTFD */ |
184 | ||
185 | /* mm helpers */ | |
2b740303 SJ |
186 | static inline vm_fault_t handle_userfault(struct vm_fault *vmf, |
187 | unsigned long reason) | |
932b18e0 AA |
188 | { |
189 | return VM_FAULT_SIGBUS; | |
190 | } | |
191 | ||
192 | static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, | |
193 | struct vm_userfaultfd_ctx vm_ctx) | |
194 | { | |
195 | return true; | |
196 | } | |
197 | ||
198 | static inline bool userfaultfd_missing(struct vm_area_struct *vma) | |
199 | { | |
200 | return false; | |
201 | } | |
202 | ||
1df319e0 SL |
203 | static inline bool userfaultfd_wp(struct vm_area_struct *vma) |
204 | { | |
205 | return false; | |
206 | } | |
207 | ||
7677f7fd AR |
208 | static inline bool userfaultfd_minor(struct vm_area_struct *vma) |
209 | { | |
210 | return false; | |
211 | } | |
212 | ||
55adf4de AA |
213 | static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, |
214 | pte_t pte) | |
215 | { | |
216 | return false; | |
217 | } | |
218 | ||
219 | static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma, | |
220 | pmd_t pmd) | |
221 | { | |
222 | return false; | |
223 | } | |
224 | ||
225 | ||
932b18e0 AA |
226 | static inline bool userfaultfd_armed(struct vm_area_struct *vma) |
227 | { | |
228 | return false; | |
229 | } | |
230 | ||
893e26e6 PE |
231 | static inline int dup_userfaultfd(struct vm_area_struct *vma, |
232 | struct list_head *l) | |
233 | { | |
234 | return 0; | |
235 | } | |
236 | ||
237 | static inline void dup_userfaultfd_complete(struct list_head *l) | |
238 | { | |
239 | } | |
240 | ||
72f87654 PE |
241 | static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, |
242 | struct vm_userfaultfd_ctx *ctx) | |
243 | { | |
244 | } | |
245 | ||
90794bf1 | 246 | static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx, |
72f87654 PE |
247 | unsigned long from, |
248 | unsigned long to, | |
249 | unsigned long len) | |
250 | { | |
251 | } | |
05ce7724 | 252 | |
70ccb92f | 253 | static inline bool userfaultfd_remove(struct vm_area_struct *vma, |
d811914d MR |
254 | unsigned long start, |
255 | unsigned long end) | |
05ce7724 | 256 | { |
70ccb92f | 257 | return true; |
05ce7724 | 258 | } |
897ab3e0 | 259 | |
69dbe6da | 260 | static inline int userfaultfd_unmap_prep(struct mm_struct *mm, |
897ab3e0 MR |
261 | unsigned long start, unsigned long end, |
262 | struct list_head *uf) | |
263 | { | |
264 | return 0; | |
265 | } | |
266 | ||
267 | static inline void userfaultfd_unmap_complete(struct mm_struct *mm, | |
268 | struct list_head *uf) | |
269 | { | |
270 | } | |
ca49ca71 | 271 | |
9c28a205 PX |
272 | static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) |
273 | { | |
274 | return false; | |
275 | } | |
276 | ||
932b18e0 AA |
277 | #endif /* CONFIG_USERFAULTFD */ |
278 | ||
1db9dbc2 PX |
279 | static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) |
280 | { | |
281 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
282 | return is_pte_marker_entry(entry) && | |
283 | (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); | |
284 | #else | |
285 | return false; | |
286 | #endif | |
287 | } | |
288 | ||
289 | static inline bool pte_marker_uffd_wp(pte_t pte) | |
290 | { | |
291 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
292 | swp_entry_t entry; | |
293 | ||
294 | if (!is_swap_pte(pte)) | |
295 | return false; | |
296 | ||
297 | entry = pte_to_swp_entry(pte); | |
298 | ||
299 | return pte_marker_entry_uffd_wp(entry); | |
300 | #else | |
301 | return false; | |
302 | #endif | |
303 | } | |
304 | ||
305 | /* | |
306 | * Returns true if this is a swap pte and was uffd-wp wr-protected in either | |
307 | * forms (pte marker or a normal swap pte), false otherwise. | |
308 | */ | |
309 | static inline bool pte_swp_uffd_wp_any(pte_t pte) | |
310 | { | |
311 | #ifdef CONFIG_PTE_MARKER_UFFD_WP | |
312 | if (!is_swap_pte(pte)) | |
313 | return false; | |
314 | ||
315 | if (pte_swp_uffd_wp(pte)) | |
316 | return true; | |
317 | ||
318 | if (pte_marker_uffd_wp(pte)) | |
319 | return true; | |
320 | #endif | |
321 | return false; | |
322 | } | |
323 | ||
932b18e0 | 324 | #endif /* _LINUX_USERFAULTFD_K_H */ |