tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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) \
21static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
22
23#define KERNEL_ATTR_RW(_name) \
24static struct kobj_attribute _name##_attr = \
25 __ATTR(_name, 0644, _name##_show, _name##_store)
26
27#if defined(CONFIG_HOTPLUG)
28/* current uevent sequence number */
29static 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}
34KERNEL_ATTR_RO(uevent_seqnum);
35
36/* uevent helper program, used during early boot */
37static 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}
42static 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}
54KERNEL_ATTR_RW(uevent_helper);
55#endif
56
57#ifdef CONFIG_PROFILING
58static ssize_t profiling_show(struct kobject *kobj,
59 struct kobj_attribute *attr, char *buf)
60{
61 return sprintf(buf, "%d\n", prof_on);
62}
63static 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}
85KERNEL_ATTR_RW(profiling);
86#endif
87
88#ifdef CONFIG_KEXEC
89static 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}
94KERNEL_ATTR_RO(kexec_loaded);
95
96static 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}
101KERNEL_ATTR_RO(kexec_crash_loaded);
102
103static 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}
108static 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}
121KERNEL_ATTR_RW(kexec_crash_size);
122
123static 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}
130KERNEL_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 */
137extern const void __start_notes __attribute__((weak));
138extern const void __stop_notes __attribute__((weak));
139#define notes_size (&__stop_notes - &__start_notes)
140
141static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
142 char *buf, loff_t off, size_t count)
143{
144 memcpy(buf, &__start_notes + off, count);
145 return count;
146}
147
148static struct bin_attribute notes_attr = {
149 .attr = {
150 .name = "notes",
151 .mode = S_IRUGO,
152 },
153 .read = ¬es_read,
154};
155
156struct kobject *kernel_kobj;
157EXPORT_SYMBOL_GPL(kernel_kobj);
158
159static struct attribute * kernel_attrs[] = {
160#if defined(CONFIG_HOTPLUG)
161 &uevent_seqnum_attr.attr,
162 &uevent_helper_attr.attr,
163#endif
164#ifdef CONFIG_PROFILING
165 &profiling_attr.attr,
166#endif
167#ifdef CONFIG_KEXEC
168 &kexec_loaded_attr.attr,
169 &kexec_crash_loaded_attr.attr,
170 &kexec_crash_size_attr.attr,
171 &vmcoreinfo_attr.attr,
172#endif
173 NULL
174};
175
176static struct attribute_group kernel_attr_group = {
177 .attrs = kernel_attrs,
178};
179
180static int __init ksysfs_init(void)
181{
182 int error;
183
184 kernel_kobj = kobject_create_and_add("kernel", NULL);
185 if (!kernel_kobj) {
186 error = -ENOMEM;
187 goto exit;
188 }
189 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
190 if (error)
191 goto kset_exit;
192
193 if (notes_size > 0) {
194 notes_attr.size = notes_size;
195 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
196 if (error)
197 goto group_exit;
198 }
199
200 return 0;
201
202group_exit:
203 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
204kset_exit:
205 kobject_put(kernel_kobj);
206exit:
207 return error;
208}
209
210core_initcall(ksysfs_init);