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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
22 #define KERNEL_ATTR_RO(_name) \
23 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
24
25 #define KERNEL_ATTR_RW(_name) \
26 static struct kobj_attribute _name##_attr = \
27 __ATTR(_name, 0644, _name##_show, _name##_store)
28
29 /* current uevent sequence number */
30 static ssize_t uevent_seqnum_show(struct kobject *kobj,
31 struct kobj_attribute *attr, char *buf)
32 {
33 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
34 }
35 KERNEL_ATTR_RO(uevent_seqnum);
36
37 /* uevent helper program, used during early boot */
38 static ssize_t uevent_helper_show(struct kobject *kobj,
39 struct kobj_attribute *attr, char *buf)
40 {
41 return sprintf(buf, "%s\n", uevent_helper);
42 }
43 static ssize_t uevent_helper_store(struct kobject *kobj,
44 struct kobj_attribute *attr,
45 const char *buf, size_t count)
46 {
47 if (count+1 > UEVENT_HELPER_PATH_LEN)
48 return -ENOENT;
49 memcpy(uevent_helper, buf, count);
50 uevent_helper[count] = '\0';
51 if (count && uevent_helper[count-1] == '\n')
52 uevent_helper[count-1] = '\0';
53 return count;
54 }
55 KERNEL_ATTR_RW(uevent_helper);
56
57
58 #ifdef CONFIG_PROFILING
59 static ssize_t profiling_show(struct kobject *kobj,
60 struct kobj_attribute *attr, char *buf)
61 {
62 return sprintf(buf, "%d\n", prof_on);
63 }
64 static ssize_t profiling_store(struct kobject *kobj,
65 struct kobj_attribute *attr,
66 const char *buf, size_t count)
67 {
68 int ret;
69
70 if (prof_on)
71 return -EEXIST;
72 /*
73 * This eventually calls into get_option() which
74 * has a ton of callers and is not const. It is
75 * easiest to cast it away here.
76 */
77 profile_setup((char *)buf);
78 ret = profile_init();
79 if (ret)
80 return ret;
81 ret = create_proc_profile();
82 if (ret)
83 return ret;
84 return count;
85 }
86 KERNEL_ATTR_RW(profiling);
87 #endif
88
89 #ifdef CONFIG_KEXEC
90 static ssize_t kexec_loaded_show(struct kobject *kobj,
91 struct kobj_attribute *attr, char *buf)
92 {
93 return sprintf(buf, "%d\n", !!kexec_image);
94 }
95 KERNEL_ATTR_RO(kexec_loaded);
96
97 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
98 struct kobj_attribute *attr, char *buf)
99 {
100 return sprintf(buf, "%d\n", !!kexec_crash_image);
101 }
102 KERNEL_ATTR_RO(kexec_crash_loaded);
103
104 static ssize_t kexec_crash_size_show(struct kobject *kobj,
105 struct kobj_attribute *attr, char *buf)
106 {
107 return sprintf(buf, "%zu\n", crash_get_memory_size());
108 }
109 static ssize_t kexec_crash_size_store(struct kobject *kobj,
110 struct kobj_attribute *attr,
111 const char *buf, size_t count)
112 {
113 unsigned long cnt;
114 int ret;
115
116 if (kstrtoul(buf, 0, &cnt))
117 return -EINVAL;
118
119 ret = crash_shrink_memory(cnt);
120 return ret < 0 ? ret : count;
121 }
122 KERNEL_ATTR_RW(kexec_crash_size);
123
124 static ssize_t vmcoreinfo_show(struct kobject *kobj,
125 struct kobj_attribute *attr, char *buf)
126 {
127 return sprintf(buf, "%lx %x\n",
128 paddr_vmcoreinfo_note(),
129 (unsigned int)sizeof(vmcoreinfo_note));
130 }
131 KERNEL_ATTR_RO(vmcoreinfo);
132
133 #endif /* CONFIG_KEXEC */
134
135 /* whether file capabilities are enabled */
136 static ssize_t fscaps_show(struct kobject *kobj,
137 struct kobj_attribute *attr, char *buf)
138 {
139 return sprintf(buf, "%d\n", file_caps_enabled);
140 }
141 KERNEL_ATTR_RO(fscaps);
142
143 int rcu_expedited;
144 static ssize_t rcu_expedited_show(struct kobject *kobj,
145 struct kobj_attribute *attr, char *buf)
146 {
147 return sprintf(buf, "%d\n", rcu_expedited);
148 }
149 static ssize_t rcu_expedited_store(struct kobject *kobj,
150 struct kobj_attribute *attr,
151 const char *buf, size_t count)
152 {
153 if (kstrtoint(buf, 0, &rcu_expedited))
154 return -EINVAL;
155
156 return count;
157 }
158 KERNEL_ATTR_RW(rcu_expedited);
159
160 /*
161 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
162 */
163 extern const void __start_notes __attribute__((weak));
164 extern const void __stop_notes __attribute__((weak));
165 #define notes_size (&__stop_notes - &__start_notes)
166
167 static ssize_t notes_read(struct file *filp, struct kobject *kobj,
168 struct bin_attribute *bin_attr,
169 char *buf, loff_t off, size_t count)
170 {
171 memcpy(buf, &__start_notes + off, count);
172 return count;
173 }
174
175 static struct bin_attribute notes_attr = {
176 .attr = {
177 .name = "notes",
178 .mode = S_IRUGO,
179 },
180 .read = &notes_read,
181 };
182
183 struct kobject *kernel_kobj;
184 EXPORT_SYMBOL_GPL(kernel_kobj);
185
186 static struct attribute * kernel_attrs[] = {
187 &fscaps_attr.attr,
188 &uevent_seqnum_attr.attr,
189 &uevent_helper_attr.attr,
190 #ifdef CONFIG_PROFILING
191 &profiling_attr.attr,
192 #endif
193 #ifdef CONFIG_KEXEC
194 &kexec_loaded_attr.attr,
195 &kexec_crash_loaded_attr.attr,
196 &kexec_crash_size_attr.attr,
197 &vmcoreinfo_attr.attr,
198 #endif
199 &rcu_expedited_attr.attr,
200 NULL
201 };
202
203 static struct attribute_group kernel_attr_group = {
204 .attrs = kernel_attrs,
205 };
206
207 static int __init ksysfs_init(void)
208 {
209 int error;
210
211 kernel_kobj = kobject_create_and_add("kernel", NULL);
212 if (!kernel_kobj) {
213 error = -ENOMEM;
214 goto exit;
215 }
216 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
217 if (error)
218 goto kset_exit;
219
220 if (notes_size > 0) {
221 notes_attr.size = notes_size;
222 error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
223 if (error)
224 goto group_exit;
225 }
226
227 return 0;
228
229 group_exit:
230 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
231 kset_exit:
232 kobject_put(kernel_kobj);
233 exit:
234 return error;
235 }
236
237 core_initcall(ksysfs_init);