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 boot */
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
kexec_crash_size_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)103 static ssize_t kexec_crash_size_show(struct kobject *kobj,
104 struct kobj_attribute *attr, char *buf)
105 {
106 return sprintf(buf, "%zu\n", crash_get_memory_size());
107 }
kexec_crash_size_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)108 static ssize_t kexec_crash_size_store(struct kobject *kobj,
109 struct kobj_attribute *attr,
110 const char *buf, size_t count)
111 {
112 unsigned long cnt;
113 int ret;
114
115 if (strict_strtoul(buf, 0, &cnt))
116 return -EINVAL;
117
118 ret = crash_shrink_memory(cnt);
119 return ret < 0 ? ret : count;
120 }
121 KERNEL_ATTR_RW(kexec_crash_size);
122
vmcoreinfo_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)123 static ssize_t vmcoreinfo_show(struct kobject *kobj,
124 struct kobj_attribute *attr, char *buf)
125 {
126 return sprintf(buf, "%lx %x\n",
127 paddr_vmcoreinfo_note(),
128 (unsigned int)vmcoreinfo_max_size);
129 }
130 KERNEL_ATTR_RO(vmcoreinfo);
131
132 #endif /* CONFIG_KEXEC */
133
134 /*
135 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
136 */
137 extern const void __start_notes __attribute__((weak));
138 extern const void __stop_notes __attribute__((weak));
139 #define notes_size (&__stop_notes - &__start_notes)
140
notes_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)141 static ssize_t notes_read(struct file *filp, struct kobject *kobj,
142 struct bin_attribute *bin_attr,
143 char *buf, loff_t off, size_t count)
144 {
145 memcpy(buf, &__start_notes + off, count);
146 return count;
147 }
148
149 static struct bin_attribute notes_attr = {
150 .attr = {
151 .name = "notes",
152 .mode = S_IRUGO,
153 },
154 .read = ¬es_read,
155 };
156
157 struct kobject *kernel_kobj;
158 EXPORT_SYMBOL_GPL(kernel_kobj);
159
160 static struct attribute * kernel_attrs[] = {
161 #if defined(CONFIG_HOTPLUG)
162 &uevent_seqnum_attr.attr,
163 &uevent_helper_attr.attr,
164 #endif
165 #ifdef CONFIG_PROFILING
166 &profiling_attr.attr,
167 #endif
168 #ifdef CONFIG_KEXEC
169 &kexec_loaded_attr.attr,
170 &kexec_crash_loaded_attr.attr,
171 &kexec_crash_size_attr.attr,
172 &vmcoreinfo_attr.attr,
173 #endif
174 NULL
175 };
176
177 static struct attribute_group kernel_attr_group = {
178 .attrs = kernel_attrs,
179 };
180
ksysfs_init(void)181 static int __init ksysfs_init(void)
182 {
183 int error;
184
185 kernel_kobj = kobject_create_and_add("kernel", NULL);
186 if (!kernel_kobj) {
187 error = -ENOMEM;
188 goto exit;
189 }
190 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
191 if (error)
192 goto kset_exit;
193
194 if (notes_size > 0) {
195 notes_attr.size = notes_size;
196 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
197 if (error)
198 goto group_exit;
199 }
200
201 return 0;
202
203 group_exit:
204 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
205 kset_exit:
206 kobject_put(kernel_kobj);
207 exit:
208 return error;
209 }
210
211 core_initcall(ksysfs_init);
212