Commit | Line | Data |
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468e15fd | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which | |
4 | * are not related to any other subsystem | |
5 | * | |
6 | * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> | |
1da177e4 LT |
7 | */ |
8 | ||
d3d76fbd | 9 | #include <asm/byteorder.h> |
1da177e4 LT |
10 | #include <linux/kobject.h> |
11 | #include <linux/string.h> | |
12 | #include <linux/sysfs.h> | |
9984de1a | 13 | #include <linux/export.h> |
1da177e4 | 14 | #include <linux/init.h> |
c330dda9 | 15 | #include <linux/kexec.h> |
22b8ce94 | 16 | #include <linux/profile.h> |
1596425f | 17 | #include <linux/stat.h> |
5cb350ba | 18 | #include <linux/sched.h> |
088ab0b4 | 19 | #include <linux/capability.h> |
52f5684c | 20 | #include <linux/compiler.h> |
1da177e4 | 21 | |
5a9be7c6 | 22 | #include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */ |
7a754743 | 23 | |
d3d76fbd TW |
24 | #if defined(__LITTLE_ENDIAN) |
25 | #define CPU_BYTEORDER_STRING "little" | |
26 | #elif defined(__BIG_ENDIAN) | |
27 | #define CPU_BYTEORDER_STRING "big" | |
28 | #else | |
29 | #error Unknown byteorder | |
30 | #endif | |
31 | ||
1da177e4 | 32 | #define KERNEL_ATTR_RO(_name) \ |
386f275f | 33 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
1da177e4 LT |
34 | |
35 | #define KERNEL_ATTR_RW(_name) \ | |
a7cd9a53 | 36 | static struct kobj_attribute _name##_attr = __ATTR_RW(_name) |
1da177e4 | 37 | |
0f76e5ac | 38 | /* current uevent sequence number */ |
386f275f KS |
39 | static ssize_t uevent_seqnum_show(struct kobject *kobj, |
40 | struct kobj_attribute *attr, char *buf) | |
1da177e4 | 41 | { |
386f275f | 42 | return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); |
1da177e4 | 43 | } |
0f76e5ac KS |
44 | KERNEL_ATTR_RO(uevent_seqnum); |
45 | ||
d3d76fbd TW |
46 | /* cpu byteorder */ |
47 | static ssize_t cpu_byteorder_show(struct kobject *kobj, | |
48 | struct kobj_attribute *attr, char *buf) | |
49 | { | |
50 | return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING); | |
51 | } | |
52 | KERNEL_ATTR_RO(cpu_byteorder); | |
53 | ||
86d56134 | 54 | #ifdef CONFIG_UEVENT_HELPER |
af665852 | 55 | /* uevent helper program, used during early boot */ |
386f275f KS |
56 | static ssize_t uevent_helper_show(struct kobject *kobj, |
57 | struct kobj_attribute *attr, char *buf) | |
0f76e5ac | 58 | { |
386f275f | 59 | return sprintf(buf, "%s\n", uevent_helper); |
0f76e5ac | 60 | } |
386f275f KS |
61 | static ssize_t uevent_helper_store(struct kobject *kobj, |
62 | struct kobj_attribute *attr, | |
63 | const char *buf, size_t count) | |
0f76e5ac | 64 | { |
312c004d | 65 | if (count+1 > UEVENT_HELPER_PATH_LEN) |
0f76e5ac | 66 | return -ENOENT; |
386f275f | 67 | memcpy(uevent_helper, buf, count); |
312c004d KS |
68 | uevent_helper[count] = '\0'; |
69 | if (count && uevent_helper[count-1] == '\n') | |
70 | uevent_helper[count-1] = '\0'; | |
0f76e5ac KS |
71 | return count; |
72 | } | |
73 | KERNEL_ATTR_RW(uevent_helper); | |
86d56134 | 74 | #endif |
1da177e4 | 75 | |
22b8ce94 DH |
76 | #ifdef CONFIG_PROFILING |
77 | static ssize_t profiling_show(struct kobject *kobj, | |
78 | struct kobj_attribute *attr, char *buf) | |
79 | { | |
80 | return sprintf(buf, "%d\n", prof_on); | |
81 | } | |
82 | static ssize_t profiling_store(struct kobject *kobj, | |
83 | struct kobj_attribute *attr, | |
84 | const char *buf, size_t count) | |
85 | { | |
86 | int ret; | |
87 | ||
88 | if (prof_on) | |
89 | return -EEXIST; | |
90 | /* | |
91 | * This eventually calls into get_option() which | |
92 | * has a ton of callers and is not const. It is | |
93 | * easiest to cast it away here. | |
94 | */ | |
95 | profile_setup((char *)buf); | |
96 | ret = profile_init(); | |
97 | if (ret) | |
98 | return ret; | |
99 | ret = create_proc_profile(); | |
100 | if (ret) | |
101 | return ret; | |
102 | return count; | |
103 | } | |
104 | KERNEL_ATTR_RW(profiling); | |
105 | #endif | |
106 | ||
2965faa5 | 107 | #ifdef CONFIG_KEXEC_CORE |
386f275f KS |
108 | static ssize_t kexec_loaded_show(struct kobject *kobj, |
109 | struct kobj_attribute *attr, char *buf) | |
c330dda9 | 110 | { |
386f275f | 111 | return sprintf(buf, "%d\n", !!kexec_image); |
c330dda9 JM |
112 | } |
113 | KERNEL_ATTR_RO(kexec_loaded); | |
114 | ||
386f275f KS |
115 | static ssize_t kexec_crash_loaded_show(struct kobject *kobj, |
116 | struct kobj_attribute *attr, char *buf) | |
c330dda9 | 117 | { |
21db79e8 | 118 | return sprintf(buf, "%d\n", kexec_crash_loaded()); |
c330dda9 JM |
119 | } |
120 | KERNEL_ATTR_RO(kexec_crash_loaded); | |
fd59d231 | 121 | |
06a7f711 AW |
122 | static ssize_t kexec_crash_size_show(struct kobject *kobj, |
123 | struct kobj_attribute *attr, char *buf) | |
124 | { | |
7bb5da0d VS |
125 | ssize_t size = crash_get_memory_size(); |
126 | ||
127 | if (size < 0) | |
128 | return size; | |
129 | ||
130 | return sprintf(buf, "%zd\n", size); | |
06a7f711 AW |
131 | } |
132 | static ssize_t kexec_crash_size_store(struct kobject *kobj, | |
133 | struct kobj_attribute *attr, | |
134 | const char *buf, size_t count) | |
135 | { | |
136 | unsigned long cnt; | |
137 | int ret; | |
138 | ||
6072ddc8 | 139 | if (kstrtoul(buf, 0, &cnt)) |
06a7f711 AW |
140 | return -EINVAL; |
141 | ||
142 | ret = crash_shrink_memory(cnt); | |
143 | return ret < 0 ? ret : count; | |
144 | } | |
145 | KERNEL_ATTR_RW(kexec_crash_size); | |
146 | ||
692f66f2 HB |
147 | #endif /* CONFIG_KEXEC_CORE */ |
148 | ||
149 | #ifdef CONFIG_CRASH_CORE | |
150 | ||
386f275f KS |
151 | static ssize_t vmcoreinfo_show(struct kobject *kobj, |
152 | struct kobj_attribute *attr, char *buf) | |
fd59d231 | 153 | { |
dae28018 RK |
154 | phys_addr_t vmcore_base = paddr_vmcoreinfo_note(); |
155 | return sprintf(buf, "%pa %x\n", &vmcore_base, | |
203e9e41 | 156 | (unsigned int)VMCOREINFO_NOTE_SIZE); |
fd59d231 KO |
157 | } |
158 | KERNEL_ATTR_RO(vmcoreinfo); | |
159 | ||
692f66f2 | 160 | #endif /* CONFIG_CRASH_CORE */ |
c330dda9 | 161 | |
088ab0b4 LN |
162 | /* whether file capabilities are enabled */ |
163 | static ssize_t fscaps_show(struct kobject *kobj, | |
164 | struct kobj_attribute *attr, char *buf) | |
165 | { | |
166 | return sprintf(buf, "%d\n", file_caps_enabled); | |
167 | } | |
168 | KERNEL_ATTR_RO(fscaps); | |
169 | ||
79cfea02 | 170 | #ifndef CONFIG_TINY_RCU |
3705b88d AM |
171 | int rcu_expedited; |
172 | static ssize_t rcu_expedited_show(struct kobject *kobj, | |
173 | struct kobj_attribute *attr, char *buf) | |
174 | { | |
5a9be7c6 | 175 | return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited)); |
3705b88d AM |
176 | } |
177 | static ssize_t rcu_expedited_store(struct kobject *kobj, | |
178 | struct kobj_attribute *attr, | |
179 | const char *buf, size_t count) | |
180 | { | |
181 | if (kstrtoint(buf, 0, &rcu_expedited)) | |
182 | return -EINVAL; | |
183 | ||
184 | return count; | |
185 | } | |
186 | KERNEL_ATTR_RW(rcu_expedited); | |
187 | ||
5a9be7c6 PM |
188 | int rcu_normal; |
189 | static ssize_t rcu_normal_show(struct kobject *kobj, | |
190 | struct kobj_attribute *attr, char *buf) | |
191 | { | |
192 | return sprintf(buf, "%d\n", READ_ONCE(rcu_normal)); | |
193 | } | |
194 | static ssize_t rcu_normal_store(struct kobject *kobj, | |
195 | struct kobj_attribute *attr, | |
196 | const char *buf, size_t count) | |
197 | { | |
198 | if (kstrtoint(buf, 0, &rcu_normal)) | |
199 | return -EINVAL; | |
200 | ||
201 | return count; | |
202 | } | |
203 | KERNEL_ATTR_RW(rcu_normal); | |
79cfea02 | 204 | #endif /* #ifndef CONFIG_TINY_RCU */ |
5a9be7c6 | 205 | |
da1a679c RM |
206 | /* |
207 | * Make /sys/kernel/notes give the raw contents of our kernel .notes section. | |
208 | */ | |
52f5684c GID |
209 | extern const void __start_notes __weak; |
210 | extern const void __stop_notes __weak; | |
da1a679c RM |
211 | #define notes_size (&__stop_notes - &__start_notes) |
212 | ||
2c3c8bea CW |
213 | static ssize_t notes_read(struct file *filp, struct kobject *kobj, |
214 | struct bin_attribute *bin_attr, | |
da1a679c RM |
215 | char *buf, loff_t off, size_t count) |
216 | { | |
217 | memcpy(buf, &__start_notes + off, count); | |
218 | return count; | |
219 | } | |
220 | ||
738bc38d | 221 | static struct bin_attribute notes_attr __ro_after_init = { |
da1a679c RM |
222 | .attr = { |
223 | .name = "notes", | |
224 | .mode = S_IRUGO, | |
225 | }, | |
226 | .read = ¬es_read, | |
227 | }; | |
228 | ||
0ff21e46 GKH |
229 | struct kobject *kernel_kobj; |
230 | EXPORT_SYMBOL_GPL(kernel_kobj); | |
1da177e4 LT |
231 | |
232 | static struct attribute * kernel_attrs[] = { | |
088ab0b4 | 233 | &fscaps_attr.attr, |
0f76e5ac | 234 | &uevent_seqnum_attr.attr, |
d3d76fbd | 235 | &cpu_byteorder_attr.attr, |
86d56134 | 236 | #ifdef CONFIG_UEVENT_HELPER |
0f76e5ac | 237 | &uevent_helper_attr.attr, |
86d56134 | 238 | #endif |
22b8ce94 DH |
239 | #ifdef CONFIG_PROFILING |
240 | &profiling_attr.attr, | |
241 | #endif | |
2965faa5 | 242 | #ifdef CONFIG_KEXEC_CORE |
c330dda9 JM |
243 | &kexec_loaded_attr.attr, |
244 | &kexec_crash_loaded_attr.attr, | |
06a7f711 | 245 | &kexec_crash_size_attr.attr, |
692f66f2 HB |
246 | #endif |
247 | #ifdef CONFIG_CRASH_CORE | |
fd59d231 | 248 | &vmcoreinfo_attr.attr, |
1da177e4 | 249 | #endif |
79cfea02 | 250 | #ifndef CONFIG_TINY_RCU |
3705b88d | 251 | &rcu_expedited_attr.attr, |
5a9be7c6 | 252 | &rcu_normal_attr.attr, |
79cfea02 | 253 | #endif |
1da177e4 LT |
254 | NULL |
255 | }; | |
256 | ||
9dcdcea1 | 257 | static const struct attribute_group kernel_attr_group = { |
1da177e4 LT |
258 | .attrs = kernel_attrs, |
259 | }; | |
260 | ||
261 | static int __init ksysfs_init(void) | |
262 | { | |
bd35b93d | 263 | int error; |
1da177e4 | 264 | |
0ff21e46 GKH |
265 | kernel_kobj = kobject_create_and_add("kernel", NULL); |
266 | if (!kernel_kobj) { | |
bd35b93d GKH |
267 | error = -ENOMEM; |
268 | goto exit; | |
269 | } | |
0ff21e46 | 270 | error = sysfs_create_group(kernel_kobj, &kernel_attr_group); |
bd35b93d GKH |
271 | if (error) |
272 | goto kset_exit; | |
273 | ||
274 | if (notes_size > 0) { | |
da1a679c | 275 | notes_attr.size = notes_size; |
0ff21e46 | 276 | error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); |
bd35b93d GKH |
277 | if (error) |
278 | goto group_exit; | |
da1a679c RM |
279 | } |
280 | ||
bd35b93d GKH |
281 | return 0; |
282 | ||
bd35b93d | 283 | group_exit: |
0ff21e46 | 284 | sysfs_remove_group(kernel_kobj, &kernel_attr_group); |
bd35b93d | 285 | kset_exit: |
78a2d906 | 286 | kobject_put(kernel_kobj); |
bd35b93d | 287 | exit: |
1da177e4 LT |
288 | return error; |
289 | } | |
290 | ||
291 | core_initcall(ksysfs_init); |