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 | { |
2444a80c | 42 | return sysfs_emit(buf, "%llu\n", (u64)atomic64_read(&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 | ||
00142bfd TW |
54 | /* address bits */ |
55 | static ssize_t address_bits_show(struct kobject *kobj, | |
56 | struct kobj_attribute *attr, char *buf) | |
57 | { | |
58 | return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */); | |
59 | } | |
60 | KERNEL_ATTR_RO(address_bits); | |
61 | ||
86d56134 | 62 | #ifdef CONFIG_UEVENT_HELPER |
af665852 | 63 | /* uevent helper program, used during early boot */ |
386f275f KS |
64 | static ssize_t uevent_helper_show(struct kobject *kobj, |
65 | struct kobj_attribute *attr, char *buf) | |
0f76e5ac | 66 | { |
9f33a88c | 67 | return sysfs_emit(buf, "%s\n", uevent_helper); |
0f76e5ac | 68 | } |
386f275f KS |
69 | static ssize_t uevent_helper_store(struct kobject *kobj, |
70 | struct kobj_attribute *attr, | |
71 | const char *buf, size_t count) | |
0f76e5ac | 72 | { |
312c004d | 73 | if (count+1 > UEVENT_HELPER_PATH_LEN) |
0f76e5ac | 74 | return -ENOENT; |
386f275f | 75 | memcpy(uevent_helper, buf, count); |
312c004d KS |
76 | uevent_helper[count] = '\0'; |
77 | if (count && uevent_helper[count-1] == '\n') | |
78 | uevent_helper[count-1] = '\0'; | |
0f76e5ac KS |
79 | return count; |
80 | } | |
81 | KERNEL_ATTR_RW(uevent_helper); | |
86d56134 | 82 | #endif |
1da177e4 | 83 | |
22b8ce94 DH |
84 | #ifdef CONFIG_PROFILING |
85 | static ssize_t profiling_show(struct kobject *kobj, | |
86 | struct kobj_attribute *attr, char *buf) | |
87 | { | |
9f33a88c | 88 | return sysfs_emit(buf, "%d\n", prof_on); |
22b8ce94 DH |
89 | } |
90 | static ssize_t profiling_store(struct kobject *kobj, | |
91 | struct kobj_attribute *attr, | |
92 | const char *buf, size_t count) | |
93 | { | |
94 | int ret; | |
7c51f7bb | 95 | static DEFINE_MUTEX(lock); |
22b8ce94 | 96 | |
7c51f7bb TH |
97 | /* |
98 | * We need serialization, for profile_setup() initializes prof_on | |
99 | * value and profile_init() must not reallocate prof_buffer after | |
100 | * once allocated. | |
101 | */ | |
102 | guard(mutex)(&lock); | |
22b8ce94 DH |
103 | if (prof_on) |
104 | return -EEXIST; | |
105 | /* | |
106 | * This eventually calls into get_option() which | |
107 | * has a ton of callers and is not const. It is | |
108 | * easiest to cast it away here. | |
109 | */ | |
110 | profile_setup((char *)buf); | |
111 | ret = profile_init(); | |
112 | if (ret) | |
113 | return ret; | |
114 | ret = create_proc_profile(); | |
115 | if (ret) | |
116 | return ret; | |
117 | return count; | |
118 | } | |
119 | KERNEL_ATTR_RW(profiling); | |
120 | #endif | |
121 | ||
2965faa5 | 122 | #ifdef CONFIG_KEXEC_CORE |
386f275f KS |
123 | static ssize_t kexec_loaded_show(struct kobject *kobj, |
124 | struct kobj_attribute *attr, char *buf) | |
c330dda9 | 125 | { |
9f33a88c | 126 | return sysfs_emit(buf, "%d\n", !!kexec_image); |
c330dda9 JM |
127 | } |
128 | KERNEL_ATTR_RO(kexec_loaded); | |
129 | ||
02aff848 | 130 | #ifdef CONFIG_CRASH_DUMP |
386f275f KS |
131 | static ssize_t kexec_crash_loaded_show(struct kobject *kobj, |
132 | struct kobj_attribute *attr, char *buf) | |
c330dda9 | 133 | { |
9f33a88c | 134 | return sysfs_emit(buf, "%d\n", kexec_crash_loaded()); |
c330dda9 JM |
135 | } |
136 | KERNEL_ATTR_RO(kexec_crash_loaded); | |
fd59d231 | 137 | |
06a7f711 AW |
138 | static ssize_t kexec_crash_size_show(struct kobject *kobj, |
139 | struct kobj_attribute *attr, char *buf) | |
140 | { | |
7bb5da0d VS |
141 | ssize_t size = crash_get_memory_size(); |
142 | ||
143 | if (size < 0) | |
144 | return size; | |
145 | ||
9f33a88c | 146 | return sysfs_emit(buf, "%zd\n", size); |
06a7f711 AW |
147 | } |
148 | static ssize_t kexec_crash_size_store(struct kobject *kobj, | |
149 | struct kobj_attribute *attr, | |
150 | const char *buf, size_t count) | |
151 | { | |
152 | unsigned long cnt; | |
153 | int ret; | |
154 | ||
6072ddc8 | 155 | if (kstrtoul(buf, 0, &cnt)) |
06a7f711 AW |
156 | return -EINVAL; |
157 | ||
158 | ret = crash_shrink_memory(cnt); | |
159 | return ret < 0 ? ret : count; | |
160 | } | |
161 | KERNEL_ATTR_RW(kexec_crash_size); | |
162 | ||
02aff848 | 163 | #endif /* CONFIG_CRASH_DUMP*/ |
692f66f2 HB |
164 | #endif /* CONFIG_KEXEC_CORE */ |
165 | ||
443cbaf9 | 166 | #ifdef CONFIG_VMCORE_INFO |
692f66f2 | 167 | |
386f275f KS |
168 | static ssize_t vmcoreinfo_show(struct kobject *kobj, |
169 | struct kobj_attribute *attr, char *buf) | |
fd59d231 | 170 | { |
dae28018 | 171 | phys_addr_t vmcore_base = paddr_vmcoreinfo_note(); |
9f33a88c TW |
172 | return sysfs_emit(buf, "%pa %x\n", &vmcore_base, |
173 | (unsigned int)VMCOREINFO_NOTE_SIZE); | |
fd59d231 KO |
174 | } |
175 | KERNEL_ATTR_RO(vmcoreinfo); | |
176 | ||
a72bbec7 ED |
177 | #ifdef CONFIG_CRASH_HOTPLUG |
178 | static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj, | |
179 | struct kobj_attribute *attr, char *buf) | |
180 | { | |
181 | unsigned int sz = crash_get_elfcorehdr_size(); | |
182 | ||
183 | return sysfs_emit(buf, "%u\n", sz); | |
184 | } | |
185 | KERNEL_ATTR_RO(crash_elfcorehdr_size); | |
186 | ||
187 | #endif | |
188 | ||
443cbaf9 | 189 | #endif /* CONFIG_VMCORE_INFO */ |
c330dda9 | 190 | |
088ab0b4 LN |
191 | /* whether file capabilities are enabled */ |
192 | static ssize_t fscaps_show(struct kobject *kobj, | |
193 | struct kobj_attribute *attr, char *buf) | |
194 | { | |
9f33a88c | 195 | return sysfs_emit(buf, "%d\n", file_caps_enabled); |
088ab0b4 LN |
196 | } |
197 | KERNEL_ATTR_RO(fscaps); | |
198 | ||
79cfea02 | 199 | #ifndef CONFIG_TINY_RCU |
3705b88d AM |
200 | int rcu_expedited; |
201 | static ssize_t rcu_expedited_show(struct kobject *kobj, | |
202 | struct kobj_attribute *attr, char *buf) | |
203 | { | |
9f33a88c | 204 | return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited)); |
3705b88d AM |
205 | } |
206 | static ssize_t rcu_expedited_store(struct kobject *kobj, | |
207 | struct kobj_attribute *attr, | |
208 | const char *buf, size_t count) | |
209 | { | |
210 | if (kstrtoint(buf, 0, &rcu_expedited)) | |
211 | return -EINVAL; | |
212 | ||
213 | return count; | |
214 | } | |
215 | KERNEL_ATTR_RW(rcu_expedited); | |
216 | ||
5a9be7c6 PM |
217 | int rcu_normal; |
218 | static ssize_t rcu_normal_show(struct kobject *kobj, | |
219 | struct kobj_attribute *attr, char *buf) | |
220 | { | |
9f33a88c | 221 | return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal)); |
5a9be7c6 PM |
222 | } |
223 | static ssize_t rcu_normal_store(struct kobject *kobj, | |
224 | struct kobj_attribute *attr, | |
225 | const char *buf, size_t count) | |
226 | { | |
227 | if (kstrtoint(buf, 0, &rcu_normal)) | |
228 | return -EINVAL; | |
229 | ||
230 | return count; | |
231 | } | |
232 | KERNEL_ATTR_RW(rcu_normal); | |
79cfea02 | 233 | #endif /* #ifndef CONFIG_TINY_RCU */ |
5a9be7c6 | 234 | |
da1a679c RM |
235 | /* |
236 | * Make /sys/kernel/notes give the raw contents of our kernel .notes section. | |
237 | */ | |
377d9095 AB |
238 | extern const void __start_notes; |
239 | extern const void __stop_notes; | |
da1a679c RM |
240 | #define notes_size (&__stop_notes - &__start_notes) |
241 | ||
2c3c8bea CW |
242 | static ssize_t notes_read(struct file *filp, struct kobject *kobj, |
243 | struct bin_attribute *bin_attr, | |
da1a679c RM |
244 | char *buf, loff_t off, size_t count) |
245 | { | |
246 | memcpy(buf, &__start_notes + off, count); | |
247 | return count; | |
248 | } | |
249 | ||
738bc38d | 250 | static struct bin_attribute notes_attr __ro_after_init = { |
da1a679c RM |
251 | .attr = { |
252 | .name = "notes", | |
253 | .mode = S_IRUGO, | |
254 | }, | |
255 | .read = ¬es_read, | |
256 | }; | |
257 | ||
0ff21e46 GKH |
258 | struct kobject *kernel_kobj; |
259 | EXPORT_SYMBOL_GPL(kernel_kobj); | |
1da177e4 LT |
260 | |
261 | static struct attribute * kernel_attrs[] = { | |
088ab0b4 | 262 | &fscaps_attr.attr, |
0f76e5ac | 263 | &uevent_seqnum_attr.attr, |
d3d76fbd | 264 | &cpu_byteorder_attr.attr, |
00142bfd | 265 | &address_bits_attr.attr, |
86d56134 | 266 | #ifdef CONFIG_UEVENT_HELPER |
0f76e5ac | 267 | &uevent_helper_attr.attr, |
86d56134 | 268 | #endif |
22b8ce94 DH |
269 | #ifdef CONFIG_PROFILING |
270 | &profiling_attr.attr, | |
271 | #endif | |
2965faa5 | 272 | #ifdef CONFIG_KEXEC_CORE |
c330dda9 | 273 | &kexec_loaded_attr.attr, |
02aff848 | 274 | #ifdef CONFIG_CRASH_DUMP |
c330dda9 | 275 | &kexec_crash_loaded_attr.attr, |
06a7f711 | 276 | &kexec_crash_size_attr.attr, |
692f66f2 | 277 | #endif |
02aff848 | 278 | #endif |
443cbaf9 | 279 | #ifdef CONFIG_VMCORE_INFO |
fd59d231 | 280 | &vmcoreinfo_attr.attr, |
a72bbec7 ED |
281 | #ifdef CONFIG_CRASH_HOTPLUG |
282 | &crash_elfcorehdr_size_attr.attr, | |
283 | #endif | |
1da177e4 | 284 | #endif |
79cfea02 | 285 | #ifndef CONFIG_TINY_RCU |
3705b88d | 286 | &rcu_expedited_attr.attr, |
5a9be7c6 | 287 | &rcu_normal_attr.attr, |
79cfea02 | 288 | #endif |
1da177e4 LT |
289 | NULL |
290 | }; | |
291 | ||
9dcdcea1 | 292 | static const struct attribute_group kernel_attr_group = { |
1da177e4 LT |
293 | .attrs = kernel_attrs, |
294 | }; | |
295 | ||
296 | static int __init ksysfs_init(void) | |
297 | { | |
bd35b93d | 298 | int error; |
1da177e4 | 299 | |
0ff21e46 GKH |
300 | kernel_kobj = kobject_create_and_add("kernel", NULL); |
301 | if (!kernel_kobj) { | |
bd35b93d GKH |
302 | error = -ENOMEM; |
303 | goto exit; | |
304 | } | |
0ff21e46 | 305 | error = sysfs_create_group(kernel_kobj, &kernel_attr_group); |
bd35b93d GKH |
306 | if (error) |
307 | goto kset_exit; | |
308 | ||
309 | if (notes_size > 0) { | |
da1a679c | 310 | notes_attr.size = notes_size; |
0ff21e46 | 311 | error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); |
bd35b93d GKH |
312 | if (error) |
313 | goto group_exit; | |
da1a679c RM |
314 | } |
315 | ||
bd35b93d GKH |
316 | return 0; |
317 | ||
bd35b93d | 318 | group_exit: |
0ff21e46 | 319 | sysfs_remove_group(kernel_kobj, &kernel_attr_group); |
bd35b93d | 320 | kset_exit: |
78a2d906 | 321 | kobject_put(kernel_kobj); |
bd35b93d | 322 | exit: |
1da177e4 LT |
323 | return error; |
324 | } | |
325 | ||
326 | core_initcall(ksysfs_init); |