2 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
3 * are not related to any other subsystem
5 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
7 * This file is release under the GPLv2
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>
23 #include <linux/rcupdate.h> /* rcu_expedited */
25 #define KERNEL_ATTR_RO(_name) \
26 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
28 #define KERNEL_ATTR_RW(_name) \
29 static struct kobj_attribute _name##_attr = \
30 __ATTR(_name, 0644, _name##_show, _name##_store)
32 /* current uevent sequence number */
33 static ssize_t uevent_seqnum_show(struct kobject *kobj,
34 struct kobj_attribute *attr, char *buf)
36 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
38 KERNEL_ATTR_RO(uevent_seqnum);
40 #ifdef CONFIG_UEVENT_HELPER
41 /* uevent helper program, used during early boot */
42 static ssize_t uevent_helper_show(struct kobject *kobj,
43 struct kobj_attribute *attr, char *buf)
45 return sprintf(buf, "%s\n", uevent_helper);
47 static ssize_t uevent_helper_store(struct kobject *kobj,
48 struct kobj_attribute *attr,
49 const char *buf, size_t count)
51 if (count+1 > UEVENT_HELPER_PATH_LEN)
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';
59 KERNEL_ATTR_RW(uevent_helper);
62 #ifdef CONFIG_PROFILING
63 static ssize_t profiling_show(struct kobject *kobj,
64 struct kobj_attribute *attr, char *buf)
66 return sprintf(buf, "%d\n", prof_on);
68 static ssize_t profiling_store(struct kobject *kobj,
69 struct kobj_attribute *attr,
70 const char *buf, size_t count)
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.
81 profile_setup((char *)buf);
85 ret = create_proc_profile();
90 KERNEL_ATTR_RW(profiling);
94 static ssize_t kexec_loaded_show(struct kobject *kobj,
95 struct kobj_attribute *attr, char *buf)
97 return sprintf(buf, "%d\n", !!kexec_image);
99 KERNEL_ATTR_RO(kexec_loaded);
101 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
102 struct kobj_attribute *attr, char *buf)
104 return sprintf(buf, "%d\n", !!kexec_crash_image);
106 KERNEL_ATTR_RO(kexec_crash_loaded);
108 static ssize_t kexec_crash_size_show(struct kobject *kobj,
109 struct kobj_attribute *attr, char *buf)
111 return sprintf(buf, "%zu\n", crash_get_memory_size());
113 static ssize_t kexec_crash_size_store(struct kobject *kobj,
114 struct kobj_attribute *attr,
115 const char *buf, size_t count)
120 if (kstrtoul(buf, 0, &cnt))
123 ret = crash_shrink_memory(cnt);
124 return ret < 0 ? ret : count;
126 KERNEL_ATTR_RW(kexec_crash_size);
128 static ssize_t vmcoreinfo_show(struct kobject *kobj,
129 struct kobj_attribute *attr, char *buf)
131 return sprintf(buf, "%lx %x\n",
132 paddr_vmcoreinfo_note(),
133 (unsigned int)sizeof(vmcoreinfo_note));
135 KERNEL_ATTR_RO(vmcoreinfo);
137 #endif /* CONFIG_KEXEC */
139 /* whether file capabilities are enabled */
140 static ssize_t fscaps_show(struct kobject *kobj,
141 struct kobj_attribute *attr, char *buf)
143 return sprintf(buf, "%d\n", file_caps_enabled);
145 KERNEL_ATTR_RO(fscaps);
148 static ssize_t rcu_expedited_show(struct kobject *kobj,
149 struct kobj_attribute *attr, char *buf)
151 return sprintf(buf, "%d\n", rcu_expedited);
153 static ssize_t rcu_expedited_store(struct kobject *kobj,
154 struct kobj_attribute *attr,
155 const char *buf, size_t count)
157 if (kstrtoint(buf, 0, &rcu_expedited))
162 KERNEL_ATTR_RW(rcu_expedited);
165 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
167 extern const void __start_notes __weak;
168 extern const void __stop_notes __weak;
169 #define notes_size (&__stop_notes - &__start_notes)
171 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)
175 memcpy(buf, &__start_notes + off, count);
179 static struct bin_attribute notes_attr = {
187 struct kobject *kernel_kobj;
188 EXPORT_SYMBOL_GPL(kernel_kobj);
190 static struct attribute * kernel_attrs[] = {
192 &uevent_seqnum_attr.attr,
193 #ifdef CONFIG_UEVENT_HELPER
194 &uevent_helper_attr.attr,
196 #ifdef CONFIG_PROFILING
197 &profiling_attr.attr,
200 &kexec_loaded_attr.attr,
201 &kexec_crash_loaded_attr.attr,
202 &kexec_crash_size_attr.attr,
203 &vmcoreinfo_attr.attr,
205 &rcu_expedited_attr.attr,
209 static struct attribute_group kernel_attr_group = {
210 .attrs = kernel_attrs,
213 static int __init ksysfs_init(void)
217 kernel_kobj = kobject_create_and_add("kernel", NULL);
222 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
226 if (notes_size > 0) {
227 notes_attr.size = notes_size;
228 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
236 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
238 kobject_put(kernel_kobj);
243 core_initcall(ksysfs_init);