1 | // SPDX-License-Identifier: GPL-2.0-only |
---|---|
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> |
7 | */ |
8 | |
9 | #include <asm/byteorder.h> |
10 | #include <linux/kobject.h> |
11 | #include <linux/string.h> |
12 | #include <linux/sysfs.h> |
13 | #include <linux/export.h> |
14 | #include <linux/init.h> |
15 | #include <linux/kexec.h> |
16 | #include <linux/profile.h> |
17 | #include <linux/stat.h> |
18 | #include <linux/sched.h> |
19 | #include <linux/capability.h> |
20 | #include <linux/compiler.h> |
21 | |
22 | #include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */ |
23 | |
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 | |
32 | #define KERNEL_ATTR_RO(_name) \ |
33 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
34 | |
35 | #define KERNEL_ATTR_RW(_name) \ |
36 | static struct kobj_attribute _name##_attr = __ATTR_RW(_name) |
37 | |
38 | /* current uevent sequence number */ |
39 | static ssize_t uevent_seqnum_show(struct kobject *kobj, |
40 | struct kobj_attribute *attr, char *buf) |
41 | { |
42 | return sysfs_emit(buf, fmt: "%llu\n", (u64)atomic64_read(v: &uevent_seqnum)); |
43 | } |
44 | KERNEL_ATTR_RO(uevent_seqnum); |
45 | |
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, fmt: "%s\n", CPU_BYTEORDER_STRING); |
51 | } |
52 | KERNEL_ATTR_RO(cpu_byteorder); |
53 | |
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, fmt: "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */); |
59 | } |
60 | KERNEL_ATTR_RO(address_bits); |
61 | |
62 | #ifdef CONFIG_UEVENT_HELPER |
63 | /* uevent helper program, used during early boot */ |
64 | static ssize_t uevent_helper_show(struct kobject *kobj, |
65 | struct kobj_attribute *attr, char *buf) |
66 | { |
67 | return sysfs_emit(buf, fmt: "%s\n", uevent_helper); |
68 | } |
69 | static ssize_t uevent_helper_store(struct kobject *kobj, |
70 | struct kobj_attribute *attr, |
71 | const char *buf, size_t count) |
72 | { |
73 | if (count+1 > UEVENT_HELPER_PATH_LEN) |
74 | return -ENOENT; |
75 | memcpy(uevent_helper, buf, count); |
76 | uevent_helper[count] = '\0'; |
77 | if (count && uevent_helper[count-1] == '\n') |
78 | uevent_helper[count-1] = '\0'; |
79 | return count; |
80 | } |
81 | KERNEL_ATTR_RW(uevent_helper); |
82 | #endif |
83 | |
84 | #ifdef CONFIG_PROFILING |
85 | static ssize_t profiling_show(struct kobject *kobj, |
86 | struct kobj_attribute *attr, char *buf) |
87 | { |
88 | return sysfs_emit(buf, fmt: "%d\n", prof_on); |
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; |
95 | static DEFINE_MUTEX(lock); |
96 | |
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)(T: &lock); |
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(str: (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 | |
122 | #ifdef CONFIG_KEXEC_CORE |
123 | static ssize_t kexec_loaded_show(struct kobject *kobj, |
124 | struct kobj_attribute *attr, char *buf) |
125 | { |
126 | return sysfs_emit(buf, fmt: "%d\n", !!kexec_image); |
127 | } |
128 | KERNEL_ATTR_RO(kexec_loaded); |
129 | |
130 | #ifdef CONFIG_CRASH_DUMP |
131 | static ssize_t kexec_crash_loaded_show(struct kobject *kobj, |
132 | struct kobj_attribute *attr, char *buf) |
133 | { |
134 | return sysfs_emit(buf, fmt: "%d\n", kexec_crash_loaded()); |
135 | } |
136 | KERNEL_ATTR_RO(kexec_crash_loaded); |
137 | |
138 | static ssize_t kexec_crash_size_show(struct kobject *kobj, |
139 | struct kobj_attribute *attr, char *buf) |
140 | { |
141 | ssize_t size = crash_get_memory_size(); |
142 | |
143 | if (size < 0) |
144 | return size; |
145 | |
146 | return sysfs_emit(buf, fmt: "%zd\n", size); |
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 | |
155 | if (kstrtoul(s: buf, base: 0, res: &cnt)) |
156 | return -EINVAL; |
157 | |
158 | ret = crash_shrink_memory(new_size: cnt); |
159 | return ret < 0 ? ret : count; |
160 | } |
161 | KERNEL_ATTR_RW(kexec_crash_size); |
162 | |
163 | #endif /* CONFIG_CRASH_DUMP*/ |
164 | #endif /* CONFIG_KEXEC_CORE */ |
165 | |
166 | #ifdef CONFIG_VMCORE_INFO |
167 | |
168 | static ssize_t vmcoreinfo_show(struct kobject *kobj, |
169 | struct kobj_attribute *attr, char *buf) |
170 | { |
171 | phys_addr_t vmcore_base = paddr_vmcoreinfo_note(); |
172 | return sysfs_emit(buf, fmt: "%pa %x\n", &vmcore_base, |
173 | (unsigned int)VMCOREINFO_NOTE_SIZE); |
174 | } |
175 | KERNEL_ATTR_RO(vmcoreinfo); |
176 | |
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, fmt: "%u\n", sz); |
184 | } |
185 | KERNEL_ATTR_RO(crash_elfcorehdr_size); |
186 | |
187 | #endif |
188 | |
189 | #endif /* CONFIG_VMCORE_INFO */ |
190 | |
191 | /* whether file capabilities are enabled */ |
192 | static ssize_t fscaps_show(struct kobject *kobj, |
193 | struct kobj_attribute *attr, char *buf) |
194 | { |
195 | return sysfs_emit(buf, fmt: "%d\n", file_caps_enabled); |
196 | } |
197 | KERNEL_ATTR_RO(fscaps); |
198 | |
199 | #ifndef CONFIG_TINY_RCU |
200 | int rcu_expedited; |
201 | static ssize_t rcu_expedited_show(struct kobject *kobj, |
202 | struct kobj_attribute *attr, char *buf) |
203 | { |
204 | return sysfs_emit(buf, fmt: "%d\n", READ_ONCE(rcu_expedited)); |
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(s: buf, base: 0, res: &rcu_expedited)) |
211 | return -EINVAL; |
212 | |
213 | return count; |
214 | } |
215 | KERNEL_ATTR_RW(rcu_expedited); |
216 | |
217 | int rcu_normal; |
218 | static ssize_t rcu_normal_show(struct kobject *kobj, |
219 | struct kobj_attribute *attr, char *buf) |
220 | { |
221 | return sysfs_emit(buf, fmt: "%d\n", READ_ONCE(rcu_normal)); |
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(s: buf, base: 0, res: &rcu_normal)) |
228 | return -EINVAL; |
229 | |
230 | return count; |
231 | } |
232 | KERNEL_ATTR_RW(rcu_normal); |
233 | #endif /* #ifndef CONFIG_TINY_RCU */ |
234 | |
235 | /* |
236 | * Make /sys/kernel/notes give the raw contents of our kernel .notes section. |
237 | */ |
238 | extern const void __start_notes; |
239 | extern const void __stop_notes; |
240 | #define notes_size (&__stop_notes - &__start_notes) |
241 | |
242 | static __ro_after_init BIN_ATTR_SIMPLE_RO(notes); |
243 | |
244 | struct kobject *kernel_kobj; |
245 | EXPORT_SYMBOL_GPL(kernel_kobj); |
246 | |
247 | static struct attribute * kernel_attrs[] = { |
248 | &fscaps_attr.attr, |
249 | &uevent_seqnum_attr.attr, |
250 | &cpu_byteorder_attr.attr, |
251 | &address_bits_attr.attr, |
252 | #ifdef CONFIG_UEVENT_HELPER |
253 | &uevent_helper_attr.attr, |
254 | #endif |
255 | #ifdef CONFIG_PROFILING |
256 | &profiling_attr.attr, |
257 | #endif |
258 | #ifdef CONFIG_KEXEC_CORE |
259 | &kexec_loaded_attr.attr, |
260 | #ifdef CONFIG_CRASH_DUMP |
261 | &kexec_crash_loaded_attr.attr, |
262 | &kexec_crash_size_attr.attr, |
263 | #endif |
264 | #endif |
265 | #ifdef CONFIG_VMCORE_INFO |
266 | &vmcoreinfo_attr.attr, |
267 | #ifdef CONFIG_CRASH_HOTPLUG |
268 | &crash_elfcorehdr_size_attr.attr, |
269 | #endif |
270 | #endif |
271 | #ifndef CONFIG_TINY_RCU |
272 | &rcu_expedited_attr.attr, |
273 | &rcu_normal_attr.attr, |
274 | #endif |
275 | NULL |
276 | }; |
277 | |
278 | static const struct attribute_group kernel_attr_group = { |
279 | .attrs = kernel_attrs, |
280 | }; |
281 | |
282 | static int __init ksysfs_init(void) |
283 | { |
284 | int error; |
285 | |
286 | kernel_kobj = kobject_create_and_add(name: "kernel", NULL); |
287 | if (!kernel_kobj) { |
288 | error = -ENOMEM; |
289 | goto exit; |
290 | } |
291 | error = sysfs_create_group(kobj: kernel_kobj, grp: &kernel_attr_group); |
292 | if (error) |
293 | goto kset_exit; |
294 | |
295 | if (notes_size > 0) { |
296 | bin_attr_notes.private = (void *)&__start_notes; |
297 | bin_attr_notes.size = notes_size; |
298 | error = sysfs_create_bin_file(kobj: kernel_kobj, attr: &bin_attr_notes); |
299 | if (error) |
300 | goto group_exit; |
301 | } |
302 | |
303 | return 0; |
304 | |
305 | group_exit: |
306 | sysfs_remove_group(kobj: kernel_kobj, grp: &kernel_attr_group); |
307 | kset_exit: |
308 | kobject_put(kobj: kernel_kobj); |
309 | exit: |
310 | return error; |
311 | } |
312 | |
313 | core_initcall(ksysfs_init); |
314 |
Definitions
- uevent_seqnum_show
- cpu_byteorder_show
- address_bits_show
- uevent_helper_show
- uevent_helper_store
- profiling_show
- profiling_store
- kexec_loaded_show
- kexec_crash_loaded_show
- kexec_crash_size_show
- kexec_crash_size_store
- vmcoreinfo_show
- crash_elfcorehdr_size_show
- fscaps_show
- rcu_expedited
- rcu_expedited_show
- rcu_expedited_store
- rcu_normal
- rcu_normal_show
- rcu_normal_store
- kernel_kobj
- kernel_attrs
- kernel_attr_group
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