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6f52b16c | 1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
1038628d AA |
2 | /* |
3 | * include/linux/userfaultfd.h | |
4 | * | |
5 | * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> | |
6 | * Copyright (C) 2015 Red Hat, Inc. | |
7 | * | |
8 | */ | |
9 | ||
10 | #ifndef _LINUX_USERFAULTFD_H | |
11 | #define _LINUX_USERFAULTFD_H | |
12 | ||
13 | #include <linux/types.h> | |
14 | ||
e067eba5 AA |
15 | /* |
16 | * If the UFFDIO_API is upgraded someday, the UFFDIO_UNREGISTER and | |
17 | * UFFDIO_WAKE ioctls should be defined as _IOW and not as _IOR. In | |
18 | * userfaultfd.h we assumed the kernel was reading (instead _IOC_READ | |
19 | * means the userland is reading). | |
20 | */ | |
1038628d | 21 | #define UFFD_API ((__u64)0xAA) |
dd0db88d | 22 | #define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_FORK | \ |
163e11bc | 23 | UFFD_FEATURE_EVENT_REMAP | \ |
d811914d | 24 | UFFD_FEATURE_EVENT_REMOVE | \ |
897ab3e0 | 25 | UFFD_FEATURE_EVENT_UNMAP | \ |
47dd9245 | 26 | UFFD_FEATURE_MISSING_HUGETLBFS | \ |
2d6d6f5a | 27 | UFFD_FEATURE_MISSING_SHMEM | \ |
9d4ac934 AP |
28 | UFFD_FEATURE_SIGBUS | \ |
29 | UFFD_FEATURE_THREAD_ID) | |
1038628d AA |
30 | #define UFFD_API_IOCTLS \ |
31 | ((__u64)1 << _UFFDIO_REGISTER | \ | |
32 | (__u64)1 << _UFFDIO_UNREGISTER | \ | |
33 | (__u64)1 << _UFFDIO_API) | |
34 | #define UFFD_API_RANGE_IOCTLS \ | |
1f1c6f07 AA |
35 | ((__u64)1 << _UFFDIO_WAKE | \ |
36 | (__u64)1 << _UFFDIO_COPY | \ | |
37 | (__u64)1 << _UFFDIO_ZEROPAGE) | |
cac67329 | 38 | #define UFFD_API_RANGE_IOCTLS_BASIC \ |
cab350af MK |
39 | ((__u64)1 << _UFFDIO_WAKE | \ |
40 | (__u64)1 << _UFFDIO_COPY) | |
1038628d AA |
41 | |
42 | /* | |
43 | * Valid ioctl command number range with this API is from 0x00 to | |
44 | * 0x3F. UFFDIO_API is the fixed number, everything else can be | |
45 | * changed by implementing a different UFFD_API. If sticking to the | |
46 | * same UFFD_API more ioctl can be added and userland will be aware of | |
47 | * which ioctl the running kernel implements through the ioctl command | |
48 | * bitmask written by the UFFDIO_API. | |
49 | */ | |
50 | #define _UFFDIO_REGISTER (0x00) | |
51 | #define _UFFDIO_UNREGISTER (0x01) | |
52 | #define _UFFDIO_WAKE (0x02) | |
1f1c6f07 AA |
53 | #define _UFFDIO_COPY (0x03) |
54 | #define _UFFDIO_ZEROPAGE (0x04) | |
1038628d AA |
55 | #define _UFFDIO_API (0x3F) |
56 | ||
57 | /* userfaultfd ioctl ids */ | |
58 | #define UFFDIO 0xAA | |
59 | #define UFFDIO_API _IOWR(UFFDIO, _UFFDIO_API, \ | |
60 | struct uffdio_api) | |
61 | #define UFFDIO_REGISTER _IOWR(UFFDIO, _UFFDIO_REGISTER, \ | |
62 | struct uffdio_register) | |
63 | #define UFFDIO_UNREGISTER _IOR(UFFDIO, _UFFDIO_UNREGISTER, \ | |
64 | struct uffdio_range) | |
65 | #define UFFDIO_WAKE _IOR(UFFDIO, _UFFDIO_WAKE, \ | |
66 | struct uffdio_range) | |
1f1c6f07 AA |
67 | #define UFFDIO_COPY _IOWR(UFFDIO, _UFFDIO_COPY, \ |
68 | struct uffdio_copy) | |
69 | #define UFFDIO_ZEROPAGE _IOWR(UFFDIO, _UFFDIO_ZEROPAGE, \ | |
70 | struct uffdio_zeropage) | |
1038628d | 71 | |
a9b85f94 AA |
72 | /* read() structure */ |
73 | struct uffd_msg { | |
74 | __u8 event; | |
75 | ||
76 | __u8 reserved1; | |
77 | __u16 reserved2; | |
78 | __u32 reserved3; | |
79 | ||
80 | union { | |
81 | struct { | |
82 | __u64 flags; | |
83 | __u64 address; | |
a36985d3 AA |
84 | union { |
85 | __u32 ptid; | |
86 | } feat; | |
a9b85f94 AA |
87 | } pagefault; |
88 | ||
893e26e6 PE |
89 | struct { |
90 | __u32 ufd; | |
91 | } fork; | |
92 | ||
72f87654 PE |
93 | struct { |
94 | __u64 from; | |
95 | __u64 to; | |
96 | __u64 len; | |
97 | } remap; | |
98 | ||
05ce7724 PE |
99 | struct { |
100 | __u64 start; | |
101 | __u64 end; | |
d811914d | 102 | } remove; |
05ce7724 | 103 | |
a9b85f94 AA |
104 | struct { |
105 | /* unused reserved fields */ | |
106 | __u64 reserved1; | |
107 | __u64 reserved2; | |
108 | __u64 reserved3; | |
109 | } reserved; | |
110 | } arg; | |
111 | } __packed; | |
1038628d | 112 | |
3f602d27 | 113 | /* |
a9b85f94 | 114 | * Start at 0x12 and not at 0 to be more strict against bugs. |
3f602d27 | 115 | */ |
a9b85f94 | 116 | #define UFFD_EVENT_PAGEFAULT 0x12 |
a9b85f94 | 117 | #define UFFD_EVENT_FORK 0x13 |
72f87654 | 118 | #define UFFD_EVENT_REMAP 0x14 |
d811914d | 119 | #define UFFD_EVENT_REMOVE 0x15 |
897ab3e0 | 120 | #define UFFD_EVENT_UNMAP 0x16 |
a9b85f94 AA |
121 | |
122 | /* flags for UFFD_EVENT_PAGEFAULT */ | |
123 | #define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */ | |
124 | #define UFFD_PAGEFAULT_FLAG_WP (1<<1) /* If reason is VM_UFFD_WP */ | |
3f602d27 | 125 | |
1038628d | 126 | struct uffdio_api { |
a9b85f94 | 127 | /* userland asks for an API number and the features to enable */ |
1038628d | 128 | __u64 api; |
a9b85f94 AA |
129 | /* |
130 | * Kernel answers below with the all available features for | |
131 | * the API, this notifies userland of which events and/or | |
132 | * which flags for each event are enabled in the current | |
133 | * kernel. | |
134 | * | |
135 | * Note: UFFD_EVENT_PAGEFAULT and UFFD_PAGEFAULT_FLAG_WRITE | |
136 | * are to be considered implicitly always enabled in all kernels as | |
137 | * long as the uffdio_api.api requested matches UFFD_API. | |
163e11bc AA |
138 | * |
139 | * UFFD_FEATURE_MISSING_HUGETLBFS means an UFFDIO_REGISTER | |
140 | * with UFFDIO_REGISTER_MODE_MISSING mode will succeed on | |
141 | * hugetlbfs virtual memory ranges. Adding or not adding | |
142 | * UFFD_FEATURE_MISSING_HUGETLBFS to uffdio_api.features has | |
143 | * no real functional effect after UFFDIO_API returns, but | |
144 | * it's only useful for an initial feature set probe at | |
145 | * UFFDIO_API time. There are two ways to use it: | |
146 | * | |
147 | * 1) by adding UFFD_FEATURE_MISSING_HUGETLBFS to the | |
148 | * uffdio_api.features before calling UFFDIO_API, an error | |
149 | * will be returned by UFFDIO_API on a kernel without | |
150 | * hugetlbfs missing support | |
151 | * | |
152 | * 2) the UFFD_FEATURE_MISSING_HUGETLBFS can not be added in | |
153 | * uffdio_api.features and instead it will be set by the | |
154 | * kernel in the uffdio_api.features if the kernel supports | |
155 | * it, so userland can later check if the feature flag is | |
156 | * present in uffdio_api.features after UFFDIO_API | |
157 | * succeeded. | |
47dd9245 AA |
158 | * |
159 | * UFFD_FEATURE_MISSING_SHMEM works the same as | |
160 | * UFFD_FEATURE_MISSING_HUGETLBFS, but it applies to shmem | |
161 | * (i.e. tmpfs and other shmem based APIs). | |
2d6d6f5a PS |
162 | * |
163 | * UFFD_FEATURE_SIGBUS feature means no page-fault | |
164 | * (UFFD_EVENT_PAGEFAULT) event will be delivered, instead | |
165 | * a SIGBUS signal will be sent to the faulting process. | |
9d4ac934 AP |
166 | * |
167 | * UFFD_FEATURE_THREAD_ID pid of the page faulted task_struct will | |
168 | * be returned, if feature is not requested 0 will be returned. | |
a9b85f94 | 169 | */ |
a9b85f94 AA |
170 | #define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) |
171 | #define UFFD_FEATURE_EVENT_FORK (1<<1) | |
72f87654 | 172 | #define UFFD_FEATURE_EVENT_REMAP (1<<2) |
d811914d | 173 | #define UFFD_FEATURE_EVENT_REMOVE (1<<3) |
163e11bc | 174 | #define UFFD_FEATURE_MISSING_HUGETLBFS (1<<4) |
47dd9245 | 175 | #define UFFD_FEATURE_MISSING_SHMEM (1<<5) |
897ab3e0 | 176 | #define UFFD_FEATURE_EVENT_UNMAP (1<<6) |
2d6d6f5a | 177 | #define UFFD_FEATURE_SIGBUS (1<<7) |
9d4ac934 | 178 | #define UFFD_FEATURE_THREAD_ID (1<<8) |
3f602d27 | 179 | __u64 features; |
a9b85f94 | 180 | |
1038628d AA |
181 | __u64 ioctls; |
182 | }; | |
183 | ||
184 | struct uffdio_range { | |
185 | __u64 start; | |
186 | __u64 len; | |
187 | }; | |
188 | ||
189 | struct uffdio_register { | |
190 | struct uffdio_range range; | |
191 | #define UFFDIO_REGISTER_MODE_MISSING ((__u64)1<<0) | |
192 | #define UFFDIO_REGISTER_MODE_WP ((__u64)1<<1) | |
193 | __u64 mode; | |
194 | ||
195 | /* | |
196 | * kernel answers which ioctl commands are available for the | |
197 | * range, keep at the end as the last 8 bytes aren't read. | |
198 | */ | |
199 | __u64 ioctls; | |
200 | }; | |
201 | ||
1f1c6f07 AA |
202 | struct uffdio_copy { |
203 | __u64 dst; | |
204 | __u64 src; | |
205 | __u64 len; | |
206 | /* | |
207 | * There will be a wrprotection flag later that allows to map | |
208 | * pages wrprotected on the fly. And such a flag will be | |
209 | * available if the wrprotection ioctl are implemented for the | |
210 | * range according to the uffdio_register.ioctls. | |
211 | */ | |
212 | #define UFFDIO_COPY_MODE_DONTWAKE ((__u64)1<<0) | |
213 | __u64 mode; | |
214 | ||
215 | /* | |
216 | * "copy" is written by the ioctl and must be at the end: the | |
217 | * copy_from_user will not read the last 8 bytes. | |
218 | */ | |
219 | __s64 copy; | |
220 | }; | |
221 | ||
222 | struct uffdio_zeropage { | |
223 | struct uffdio_range range; | |
224 | #define UFFDIO_ZEROPAGE_MODE_DONTWAKE ((__u64)1<<0) | |
225 | __u64 mode; | |
226 | ||
227 | /* | |
228 | * "zeropage" is written by the ioctl and must be at the end: | |
229 | * the copy_from_user will not read the last 8 bytes. | |
230 | */ | |
231 | __s64 zeropage; | |
232 | }; | |
233 | ||
1038628d | 234 | #endif /* _LINUX_USERFAULTFD_H */ |