blob: ee1bc1bb8feb82f4873eb38106805c2823bed7b2
1 | /* |
2 | * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which |
3 | * are not related to any other subsystem |
4 | * |
5 | * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> |
6 | * |
7 | * This file is release under the GPLv2 |
8 | * |
9 | */ |
10 | |
11 | #include <linux/kobject.h> |
12 | #include <linux/string.h> |
13 | #include <linux/sysfs.h> |
14 | #include <linux/export.h> |
15 | #include <linux/init.h> |
16 | #include <linux/kexec.h> |
17 | #include <linux/profile.h> |
18 | #include <linux/stat.h> |
19 | #include <linux/sched.h> |
20 | #include <linux/capability.h> |
21 | #include <linux/compiler.h> |
22 | |
23 | #include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */ |
24 | |
25 | #define KERNEL_ATTR_RO(_name) \ |
26 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
27 | |
28 | #define KERNEL_ATTR_RW(_name) \ |
29 | static struct kobj_attribute _name##_attr = \ |
30 | __ATTR(_name, 0644, _name##_show, _name##_store) |
31 | |
32 | /* current uevent sequence number */ |
33 | static ssize_t uevent_seqnum_show(struct kobject *kobj, |
34 | struct kobj_attribute *attr, char *buf) |
35 | { |
36 | return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); |
37 | } |
38 | KERNEL_ATTR_RO(uevent_seqnum); |
39 | |
40 | #ifdef CONFIG_UEVENT_HELPER |
41 | /* uevent helper program, used during early boot */ |
42 | static ssize_t uevent_helper_show(struct kobject *kobj, |
43 | struct kobj_attribute *attr, char *buf) |
44 | { |
45 | return sprintf(buf, "%s\n", uevent_helper); |
46 | } |
47 | static ssize_t uevent_helper_store(struct kobject *kobj, |
48 | struct kobj_attribute *attr, |
49 | const char *buf, size_t count) |
50 | { |
51 | if (count+1 > UEVENT_HELPER_PATH_LEN) |
52 | return -ENOENT; |
53 | memcpy(uevent_helper, buf, count); |
54 | uevent_helper[count] = '\0'; |
55 | if (count && uevent_helper[count-1] == '\n') |
56 | uevent_helper[count-1] = '\0'; |
57 | return count; |
58 | } |
59 | KERNEL_ATTR_RW(uevent_helper); |
60 | #endif |
61 | |
62 | #ifdef CONFIG_PROFILING |
63 | static ssize_t profiling_show(struct kobject *kobj, |
64 | struct kobj_attribute *attr, char *buf) |
65 | { |
66 | return sprintf(buf, "%d\n", prof_on); |
67 | } |
68 | static ssize_t profiling_store(struct kobject *kobj, |
69 | struct kobj_attribute *attr, |
70 | const char *buf, size_t count) |
71 | { |
72 | int ret; |
73 | |
74 | if (prof_on) |
75 | return -EEXIST; |
76 | /* |
77 | * This eventually calls into get_option() which |
78 | * has a ton of callers and is not const. It is |
79 | * easiest to cast it away here. |
80 | */ |
81 | profile_setup((char *)buf); |
82 | ret = profile_init(); |
83 | if (ret) |
84 | return ret; |
85 | ret = create_proc_profile(); |
86 | if (ret) |
87 | return ret; |
88 | return count; |
89 | } |
90 | KERNEL_ATTR_RW(profiling); |
91 | #endif |
92 | |
93 | #ifdef CONFIG_KEXEC_CORE |
94 | static ssize_t kexec_loaded_show(struct kobject *kobj, |
95 | struct kobj_attribute *attr, char *buf) |
96 | { |
97 | return sprintf(buf, "%d\n", !!kexec_image); |
98 | } |
99 | KERNEL_ATTR_RO(kexec_loaded); |
100 | |
101 | static ssize_t kexec_crash_loaded_show(struct kobject *kobj, |
102 | struct kobj_attribute *attr, char *buf) |
103 | { |
104 | return sprintf(buf, "%d\n", kexec_crash_loaded()); |
105 | } |
106 | KERNEL_ATTR_RO(kexec_crash_loaded); |
107 | |
108 | static ssize_t kexec_crash_size_show(struct kobject *kobj, |
109 | struct kobj_attribute *attr, char *buf) |
110 | { |
111 | return sprintf(buf, "%zu\n", crash_get_memory_size()); |
112 | } |
113 | static ssize_t kexec_crash_size_store(struct kobject *kobj, |
114 | struct kobj_attribute *attr, |
115 | const char *buf, size_t count) |
116 | { |
117 | unsigned long cnt; |
118 | int ret; |
119 | |
120 | if (kstrtoul(buf, 0, &cnt)) |
121 | return -EINVAL; |
122 | |
123 | ret = crash_shrink_memory(cnt); |
124 | return ret < 0 ? ret : count; |
125 | } |
126 | KERNEL_ATTR_RW(kexec_crash_size); |
127 | |
128 | static ssize_t vmcoreinfo_show(struct kobject *kobj, |
129 | struct kobj_attribute *attr, char *buf) |
130 | { |
131 | phys_addr_t vmcore_base = paddr_vmcoreinfo_note(); |
132 | return sprintf(buf, "%pa %x\n", &vmcore_base, |
133 | (unsigned int)sizeof(vmcoreinfo_note)); |
134 | } |
135 | KERNEL_ATTR_RO(vmcoreinfo); |
136 | |
137 | #endif /* CONFIG_KEXEC_CORE */ |
138 | |
139 | /* whether file capabilities are enabled */ |
140 | static ssize_t fscaps_show(struct kobject *kobj, |
141 | struct kobj_attribute *attr, char *buf) |
142 | { |
143 | return sprintf(buf, "%d\n", file_caps_enabled); |
144 | } |
145 | KERNEL_ATTR_RO(fscaps); |
146 | |
147 | #ifndef CONFIG_TINY_RCU |
148 | int rcu_expedited; |
149 | static ssize_t rcu_expedited_show(struct kobject *kobj, |
150 | struct kobj_attribute *attr, char *buf) |
151 | { |
152 | return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited)); |
153 | } |
154 | static ssize_t rcu_expedited_store(struct kobject *kobj, |
155 | struct kobj_attribute *attr, |
156 | const char *buf, size_t count) |
157 | { |
158 | if (kstrtoint(buf, 0, &rcu_expedited)) |
159 | return -EINVAL; |
160 | |
161 | return count; |
162 | } |
163 | KERNEL_ATTR_RW(rcu_expedited); |
164 | |
165 | int rcu_normal; |
166 | static ssize_t rcu_normal_show(struct kobject *kobj, |
167 | struct kobj_attribute *attr, char *buf) |
168 | { |
169 | return sprintf(buf, "%d\n", READ_ONCE(rcu_normal)); |
170 | } |
171 | static ssize_t rcu_normal_store(struct kobject *kobj, |
172 | struct kobj_attribute *attr, |
173 | const char *buf, size_t count) |
174 | { |
175 | if (kstrtoint(buf, 0, &rcu_normal)) |
176 | return -EINVAL; |
177 | |
178 | return count; |
179 | } |
180 | KERNEL_ATTR_RW(rcu_normal); |
181 | #endif /* #ifndef CONFIG_TINY_RCU */ |
182 | |
183 | /* |
184 | * Make /sys/kernel/notes give the raw contents of our kernel .notes section. |
185 | */ |
186 | extern const void __start_notes __weak; |
187 | extern const void __stop_notes __weak; |
188 | #define notes_size (&__stop_notes - &__start_notes) |
189 | |
190 | static ssize_t notes_read(struct file *filp, struct kobject *kobj, |
191 | struct bin_attribute *bin_attr, |
192 | char *buf, loff_t off, size_t count) |
193 | { |
194 | memcpy(buf, &__start_notes + off, count); |
195 | return count; |
196 | } |
197 | |
198 | static struct bin_attribute notes_attr = { |
199 | .attr = { |
200 | .name = "notes", |
201 | .mode = S_IRUGO, |
202 | }, |
203 | .read = ¬es_read, |
204 | }; |
205 | |
206 | struct kobject *kernel_kobj; |
207 | EXPORT_SYMBOL_GPL(kernel_kobj); |
208 | |
209 | static struct attribute * kernel_attrs[] = { |
210 | &fscaps_attr.attr, |
211 | &uevent_seqnum_attr.attr, |
212 | #ifdef CONFIG_UEVENT_HELPER |
213 | &uevent_helper_attr.attr, |
214 | #endif |
215 | #ifdef CONFIG_PROFILING |
216 | &profiling_attr.attr, |
217 | #endif |
218 | #ifdef CONFIG_KEXEC_CORE |
219 | &kexec_loaded_attr.attr, |
220 | &kexec_crash_loaded_attr.attr, |
221 | &kexec_crash_size_attr.attr, |
222 | &vmcoreinfo_attr.attr, |
223 | #endif |
224 | #ifndef CONFIG_TINY_RCU |
225 | &rcu_expedited_attr.attr, |
226 | &rcu_normal_attr.attr, |
227 | #endif |
228 | NULL |
229 | }; |
230 | |
231 | static struct attribute_group kernel_attr_group = { |
232 | .attrs = kernel_attrs, |
233 | }; |
234 | |
235 | static int __init ksysfs_init(void) |
236 | { |
237 | int error; |
238 | |
239 | kernel_kobj = kobject_create_and_add("kernel", NULL); |
240 | if (!kernel_kobj) { |
241 | error = -ENOMEM; |
242 | goto exit; |
243 | } |
244 | error = sysfs_create_group(kernel_kobj, &kernel_attr_group); |
245 | if (error) |
246 | goto kset_exit; |
247 | |
248 | if (notes_size > 0) { |
249 | notes_attr.size = notes_size; |
250 | error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); |
251 | if (error) |
252 | goto group_exit; |
253 | } |
254 | |
255 | return 0; |
256 | |
257 | group_exit: |
258 | sysfs_remove_group(kernel_kobj, &kernel_attr_group); |
259 | kset_exit: |
260 | kobject_put(kernel_kobj); |
261 | exit: |
262 | return error; |
263 | } |
264 | |
265 | core_initcall(ksysfs_init); |
266 |