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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_image); | |
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 | return sprintf(buf, "%lx %x\n", | |
132 | paddr_vmcoreinfo_note(), | |
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); |