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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 */ | |
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 */ | |
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 | } | |
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 | |
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 | } | |
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 | |
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 | ||
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 | ||
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 | } | |
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 | ||
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 | ||
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 | ||
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); |