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/module.h>
15 #include <linux/init.h>
16 #include <linux/kexec.h>
17 #include <linux/profile.h>
18 #include <linux/sched.h>
19
20 #define KERNEL_ATTR_RO(_name) \
21 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
22
23 #define KERNEL_ATTR_RW(_name) \
24 static struct kobj_attribute _name##_attr = \
25 __ATTR(_name, 0644, _name##_show, _name##_store)
26
27 #if defined(CONFIG_HOTPLUG)
28 /* current uevent sequence number */
uevent_seqnum_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)29 static ssize_t uevent_seqnum_show(struct kobject *kobj,
30 struct kobj_attribute *attr, char *buf)
31 {
32 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
33 }
34 KERNEL_ATTR_RO(uevent_seqnum);
35
36 /* uevent helper program, used during early boo */
uevent_helper_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)37 static ssize_t uevent_helper_show(struct kobject *kobj,
38 struct kobj_attribute *attr, char *buf)
39 {
40 return sprintf(buf, "%s\n", uevent_helper);
41 }
uevent_helper_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)42 static ssize_t uevent_helper_store(struct kobject *kobj,
43 struct kobj_attribute *attr,
44 const char *buf, size_t count)
45 {
46 if (count+1 > UEVENT_HELPER_PATH_LEN)
47 return -ENOENT;
48 memcpy(uevent_helper, buf, count);
49 uevent_helper[count] = '\0';
50 if (count && uevent_helper[count-1] == '\n')
51 uevent_helper[count-1] = '\0';
52 return count;
53 }
54 KERNEL_ATTR_RW(uevent_helper);
55 #endif
56
57 #ifdef CONFIG_PROFILING
profiling_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)58 static ssize_t profiling_show(struct kobject *kobj,
59 struct kobj_attribute *attr, char *buf)
60 {
61 return sprintf(buf, "%d\n", prof_on);
62 }
profiling_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)63 static ssize_t profiling_store(struct kobject *kobj,
64 struct kobj_attribute *attr,
65 const char *buf, size_t count)
66 {
67 int ret;
68
69 if (prof_on)
70 return -EEXIST;
71 /*
72 * This eventually calls into get_option() which
73 * has a ton of callers and is not const. It is
74 * easiest to cast it away here.
75 */
76 profile_setup((char *)buf);
77 ret = profile_init();
78 if (ret)
79 return ret;
80 ret = create_proc_profile();
81 if (ret)
82 return ret;
83 return count;
84 }
85 KERNEL_ATTR_RW(profiling);
86 #endif
87
88 #ifdef CONFIG_KEXEC
kexec_loaded_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)89 static ssize_t kexec_loaded_show(struct kobject *kobj,
90 struct kobj_attribute *attr, char *buf)
91 {
92 return sprintf(buf, "%d\n", !!kexec_image);
93 }
94 KERNEL_ATTR_RO(kexec_loaded);
95
kexec_crash_loaded_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)96 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
97 struct kobj_attribute *attr, char *buf)
98 {
99 return sprintf(buf, "%d\n", !!kexec_crash_image);
100 }
101 KERNEL_ATTR_RO(kexec_crash_loaded);
102
vmcoreinfo_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)103 static ssize_t vmcoreinfo_show(struct kobject *kobj,
104 struct kobj_attribute *attr, char *buf)
105 {
106 return sprintf(buf, "%lx %x\n",
107 paddr_vmcoreinfo_note(),
108 (unsigned int)vmcoreinfo_max_size);
109 }
110 KERNEL_ATTR_RO(vmcoreinfo);
111
112 #endif /* CONFIG_KEXEC */
113
114 /*
115 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
116 */
117 extern const void __start_notes __attribute__((weak));
118 extern const void __stop_notes __attribute__((weak));
119 #define notes_size (&__stop_notes - &__start_notes)
120
notes_read(struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)121 static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
122 char *buf, loff_t off, size_t count)
123 {
124 memcpy(buf, &__start_notes + off, count);
125 return count;
126 }
127
128 static struct bin_attribute notes_attr = {
129 .attr = {
130 .name = "notes",
131 .mode = S_IRUGO,
132 },
133 .read = ¬es_read,
134 };
135
136 struct kobject *kernel_kobj;
137 EXPORT_SYMBOL_GPL(kernel_kobj);
138
139 static struct attribute * kernel_attrs[] = {
140 #if defined(CONFIG_HOTPLUG)
141 &uevent_seqnum_attr.attr,
142 &uevent_helper_attr.attr,
143 #endif
144 #ifdef CONFIG_PROFILING
145 &profiling_attr.attr,
146 #endif
147 #ifdef CONFIG_KEXEC
148 &kexec_loaded_attr.attr,
149 &kexec_crash_loaded_attr.attr,
150 &vmcoreinfo_attr.attr,
151 #endif
152 NULL
153 };
154
155 static struct attribute_group kernel_attr_group = {
156 .attrs = kernel_attrs,
157 };
158
ksysfs_init(void)159 static int __init ksysfs_init(void)
160 {
161 int error;
162
163 kernel_kobj = kobject_create_and_add("kernel", NULL);
164 if (!kernel_kobj) {
165 error = -ENOMEM;
166 goto exit;
167 }
168 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
169 if (error)
170 goto kset_exit;
171
172 if (notes_size > 0) {
173 notes_attr.size = notes_size;
174 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
175 if (error)
176 goto group_exit;
177 }
178
179 /* create the /sys/kernel/uids/ directory */
180 error = uids_sysfs_init();
181 if (error)
182 goto notes_exit;
183
184 return 0;
185
186 notes_exit:
187 if (notes_size > 0)
188 sysfs_remove_bin_file(kernel_kobj, ¬es_attr);
189 group_exit:
190 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
191 kset_exit:
192 kobject_put(kernel_kobj);
193 exit:
194 return error;
195 }
196
197 core_initcall(ksysfs_init);
198