Line data Source code
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 */
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 2 : static ssize_t uevent_seqnum_show(struct kobject *kobj,
34 : struct kobj_attribute *attr, char *buf)
35 : {
36 2 : 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 0 : static ssize_t uevent_helper_show(struct kobject *kobj,
43 : struct kobj_attribute *attr, char *buf)
44 : {
45 0 : return sprintf(buf, "%s\n", uevent_helper);
46 : }
47 1 : static ssize_t uevent_helper_store(struct kobject *kobj,
48 : struct kobj_attribute *attr,
49 : const char *buf, size_t count)
50 : {
51 1 : if (count+1 > UEVENT_HELPER_PATH_LEN)
52 : return -ENOENT;
53 1 : memcpy(uevent_helper, buf, count);
54 1 : uevent_helper[count] = '\0';
55 1 : if (count && uevent_helper[count-1] == '\n')
56 1 : uevent_helper[count-1] = '\0';
57 1 : 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
94 0 : static ssize_t kexec_loaded_show(struct kobject *kobj,
95 : struct kobj_attribute *attr, char *buf)
96 : {
97 0 : return sprintf(buf, "%d\n", !!kexec_image);
98 : }
99 : KERNEL_ATTR_RO(kexec_loaded);
100 :
101 0 : static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
102 : struct kobj_attribute *attr, char *buf)
103 : {
104 0 : return sprintf(buf, "%d\n", !!kexec_crash_image);
105 : }
106 : KERNEL_ATTR_RO(kexec_crash_loaded);
107 :
108 0 : static ssize_t kexec_crash_size_show(struct kobject *kobj,
109 : struct kobj_attribute *attr, char *buf)
110 : {
111 0 : return sprintf(buf, "%zu\n", crash_get_memory_size());
112 : }
113 0 : 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 0 : if (kstrtoul(buf, 0, &cnt))
121 : return -EINVAL;
122 :
123 0 : ret = crash_shrink_memory(cnt);
124 0 : return ret < 0 ? ret : count;
125 : }
126 : KERNEL_ATTR_RW(kexec_crash_size);
127 :
128 0 : static ssize_t vmcoreinfo_show(struct kobject *kobj,
129 : struct kobj_attribute *attr, char *buf)
130 : {
131 0 : 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 */
138 :
139 : /* whether file capabilities are enabled */
140 0 : static ssize_t fscaps_show(struct kobject *kobj,
141 : struct kobj_attribute *attr, char *buf)
142 : {
143 0 : return sprintf(buf, "%d\n", file_caps_enabled);
144 : }
145 : KERNEL_ATTR_RO(fscaps);
146 :
147 : int rcu_expedited;
148 0 : static ssize_t rcu_expedited_show(struct kobject *kobj,
149 : struct kobj_attribute *attr, char *buf)
150 : {
151 0 : return sprintf(buf, "%d\n", rcu_expedited);
152 : }
153 0 : static ssize_t rcu_expedited_store(struct kobject *kobj,
154 : struct kobj_attribute *attr,
155 : const char *buf, size_t count)
156 : {
157 0 : if (kstrtoint(buf, 0, &rcu_expedited))
158 : return -EINVAL;
159 :
160 0 : return count;
161 : }
162 : KERNEL_ATTR_RW(rcu_expedited);
163 :
164 : /*
165 : * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
166 : */
167 : extern const void __start_notes __weak;
168 : extern const void __stop_notes __weak;
169 : #define notes_size (&__stop_notes - &__start_notes)
170 :
171 0 : static ssize_t notes_read(struct file *filp, struct kobject *kobj,
172 : struct bin_attribute *bin_attr,
173 : char *buf, loff_t off, size_t count)
174 : {
175 0 : memcpy(buf, &__start_notes + off, count);
176 0 : return count;
177 : }
178 :
179 : static struct bin_attribute notes_attr = {
180 : .attr = {
181 : .name = "notes",
182 : .mode = S_IRUGO,
183 : },
184 : .read = ¬es_read,
185 : };
186 :
187 : struct kobject *kernel_kobj;
188 : EXPORT_SYMBOL_GPL(kernel_kobj);
189 :
190 : static struct attribute * kernel_attrs[] = {
191 : &fscaps_attr.attr,
192 : &uevent_seqnum_attr.attr,
193 : #ifdef CONFIG_UEVENT_HELPER
194 : &uevent_helper_attr.attr,
195 : #endif
196 : #ifdef CONFIG_PROFILING
197 : &profiling_attr.attr,
198 : #endif
199 : #ifdef CONFIG_KEXEC
200 : &kexec_loaded_attr.attr,
201 : &kexec_crash_loaded_attr.attr,
202 : &kexec_crash_size_attr.attr,
203 : &vmcoreinfo_attr.attr,
204 : #endif
205 : &rcu_expedited_attr.attr,
206 : NULL
207 : };
208 :
209 : static struct attribute_group kernel_attr_group = {
210 : .attrs = kernel_attrs,
211 : };
212 :
213 1 : static int __init ksysfs_init(void)
214 : {
215 : int error;
216 :
217 1 : kernel_kobj = kobject_create_and_add("kernel", NULL);
218 1 : if (!kernel_kobj) {
219 : error = -ENOMEM;
220 : goto exit;
221 : }
222 1 : error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
223 1 : if (error)
224 : goto kset_exit;
225 :
226 1 : if (notes_size > 0) {
227 1 : notes_attr.size = notes_size;
228 1 : error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
229 1 : if (error)
230 : goto group_exit;
231 : }
232 :
233 : return 0;
234 :
235 : group_exit:
236 0 : sysfs_remove_group(kernel_kobj, &kernel_attr_group);
237 : kset_exit:
238 0 : kobject_put(kernel_kobj);
239 : exit:
240 0 : return error;
241 : }
242 :
243 : core_initcall(ksysfs_init);
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