projects/linux·blob v4.5 · refs

265 lines · 6.2 KiB

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 <[email protected]>
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) \
26static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
27
28#define KERNEL_ATTR_RW(_name) \
29static struct kobj_attribute _name##_attr = \
30 __ATTR(_name, 0644, _name##_show, _name##_store)
31
32/* current uevent sequence number */
33static 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}
38KERNEL_ATTR_RO(uevent_seqnum);
39
40#ifdef CONFIG_UEVENT_HELPER
41/* uevent helper program, used during early boot */
42static 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}
47static 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}
59KERNEL_ATTR_RW(uevent_helper);
60#endif
61
62#ifdef CONFIG_PROFILING
63static ssize_t profiling_show(struct kobject *kobj,
64 struct kobj_attribute *attr, char *buf)
65{
66 return sprintf(buf, "%d\n", prof_on);
67}
68static 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}
90KERNEL_ATTR_RW(profiling);
91#endif
92
93#ifdef CONFIG_KEXEC_CORE
94static 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}
99KERNEL_ATTR_RO(kexec_loaded);
100
101static 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}
106KERNEL_ATTR_RO(kexec_crash_loaded);
107
108static 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}
113static 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}
126KERNEL_ATTR_RW(kexec_crash_size);
127
128static 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}
135KERNEL_ATTR_RO(vmcoreinfo);
136
137#endif /* CONFIG_KEXEC_CORE */
138
139/* whether file capabilities are enabled */
140static 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}
145KERNEL_ATTR_RO(fscaps);
146
147#ifndef CONFIG_TINY_RCU
148int rcu_expedited;
149static 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}
154static 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}
163KERNEL_ATTR_RW(rcu_expedited);
164
165int rcu_normal;
166static 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}
171static 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}
180KERNEL_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 */
186extern const void __start_notes __weak;
187extern const void __stop_notes __weak;
188#define notes_size (&__stop_notes - &__start_notes)
189
190static 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
198static struct bin_attribute notes_attr = {
199 .attr = {
200 .name = "notes",
201 .mode = S_IRUGO,
202 },
203 .read = &notes_read,
204};
205
206struct kobject *kernel_kobj;
207EXPORT_SYMBOL_GPL(kernel_kobj);
208
209static 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
231static struct attribute_group kernel_attr_group = {
232 .attrs = kernel_attrs,
233};
234
235static 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, &notes_attr);
251 if (error)
252 goto group_exit;
253 }
254
255 return 0;
256
257group_exit:
258 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
259kset_exit:
260 kobject_put(kernel_kobj);
261exit:
262 return error;
263}
264
265core_initcall(ksysfs_init);