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/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> 22 23 #include <linux/rcupdate.h> /* rcu_expedited */ 24 25 #define KERNEL_ATTR_RO(_name) \ 26 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 27 28 #define KERNEL_ATTR_RW(_name) \ 29 static struct kobj_attribute _name##_attr = \ 30 __ATTR(_name, 0644, _name##_show, _name##_store) 31 32 /* current uevent sequence number */ 33 static ssize_t uevent_seqnum_show(struct kobject *kobj, 34 struct kobj_attribute *attr, char *buf) 35 { 36 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); 37 } 38 KERNEL_ATTR_RO(uevent_seqnum); 39 40 /* uevent helper program, used during early boot */ 41 static ssize_t uevent_helper_show(struct kobject *kobj, 42 struct kobj_attribute *attr, char *buf) 43 { 44 return sprintf(buf, "%s\n", uevent_helper); 45 } 46 static ssize_t uevent_helper_store(struct kobject *kobj, 47 struct kobj_attribute *attr, 48 const char *buf, size_t count) 49 { 50 if (count+1 > UEVENT_HELPER_PATH_LEN) 51 return -ENOENT; 52 memcpy(uevent_helper, buf, count); 53 uevent_helper[count] = '\0'; 54 if (count && uevent_helper[count-1] == '\n') 55 uevent_helper[count-1] = '\0'; 56 return count; 57 } 58 KERNEL_ATTR_RW(uevent_helper); 59 60 61 #ifdef CONFIG_PROFILING 62 static ssize_t profiling_show(struct kobject *kobj, 63 struct kobj_attribute *attr, char *buf) 64 { 65 return sprintf(buf, "%d\n", prof_on); 66 } 67 static ssize_t profiling_store(struct kobject *kobj, 68 struct kobj_attribute *attr, 69 const char *buf, size_t count) 70 { 71 int ret; 72 73 if (prof_on) 74 return -EEXIST; 75 /* 76 * This eventually calls into get_option() which 77 * has a ton of callers and is not const. It is 78 * easiest to cast it away here. 79 */ 80 profile_setup((char *)buf); 81 ret = profile_init(); 82 if (ret) 83 return ret; 84 ret = create_proc_profile(); 85 if (ret) 86 return ret; 87 return count; 88 } 89 KERNEL_ATTR_RW(profiling); 90 #endif 91 92 #ifdef CONFIG_KEXEC 93 static ssize_t kexec_loaded_show(struct kobject *kobj, 94 struct kobj_attribute *attr, char *buf) 95 { 96 return sprintf(buf, "%d\n", !!kexec_image); 97 } 98 KERNEL_ATTR_RO(kexec_loaded); 99 100 static ssize_t kexec_crash_loaded_show(struct kobject *kobj, 101 struct kobj_attribute *attr, char *buf) 102 { 103 return sprintf(buf, "%d\n", !!kexec_crash_image); 104 } 105 KERNEL_ATTR_RO(kexec_crash_loaded); 106 107 static ssize_t kexec_crash_size_show(struct kobject *kobj, 108 struct kobj_attribute *attr, char *buf) 109 { 110 return sprintf(buf, "%zu\n", crash_get_memory_size()); 111 } 112 static ssize_t kexec_crash_size_store(struct kobject *kobj, 113 struct kobj_attribute *attr, 114 const char *buf, size_t count) 115 { 116 unsigned long cnt; 117 int ret; 118 119 if (kstrtoul(buf, 0, &cnt)) 120 return -EINVAL; 121 122 ret = crash_shrink_memory(cnt); 123 return ret < 0 ? ret : count; 124 } 125 KERNEL_ATTR_RW(kexec_crash_size); 126 127 static ssize_t vmcoreinfo_show(struct kobject *kobj, 128 struct kobj_attribute *attr, char *buf) 129 { 130 return sprintf(buf, "%lx %x\n", 131 paddr_vmcoreinfo_note(), 132 (unsigned int)sizeof(vmcoreinfo_note)); 133 } 134 KERNEL_ATTR_RO(vmcoreinfo); 135 136 #endif /* CONFIG_KEXEC */ 137 138 /* whether file capabilities are enabled */ 139 static ssize_t fscaps_show(struct kobject *kobj, 140 struct kobj_attribute *attr, char *buf) 141 { 142 return sprintf(buf, "%d\n", file_caps_enabled); 143 } 144 KERNEL_ATTR_RO(fscaps); 145 146 int rcu_expedited; 147 static ssize_t rcu_expedited_show(struct kobject *kobj, 148 struct kobj_attribute *attr, char *buf) 149 { 150 return sprintf(buf, "%d\n", rcu_expedited); 151 } 152 static ssize_t rcu_expedited_store(struct kobject *kobj, 153 struct kobj_attribute *attr, 154 const char *buf, size_t count) 155 { 156 if (kstrtoint(buf, 0, &rcu_expedited)) 157 return -EINVAL; 158 159 return count; 160 } 161 KERNEL_ATTR_RW(rcu_expedited); 162 163 /* 164 * Make /sys/kernel/notes give the raw contents of our kernel .notes section. 165 */ 166 extern const void __start_notes __weak; 167 extern const void __stop_notes __weak; 168 #define notes_size (&__stop_notes - &__start_notes) 169 170 static ssize_t notes_read(struct file *filp, struct kobject *kobj, 171 struct bin_attribute *bin_attr, 172 char *buf, loff_t off, size_t count) 173 { 174 memcpy(buf, &__start_notes + off, count); 175 return count; 176 } 177 178 static struct bin_attribute notes_attr = { 179 .attr = { 180 .name = "notes", 181 .mode = S_IRUGO, 182 }, 183 .read = ¬es_read, 184 }; 185 186 struct kobject *kernel_kobj; 187 EXPORT_SYMBOL_GPL(kernel_kobj); 188 189 static struct attribute * kernel_attrs[] = { 190 &fscaps_attr.attr, 191 &uevent_seqnum_attr.attr, 192 &uevent_helper_attr.attr, 193 #ifdef CONFIG_PROFILING 194 &profiling_attr.attr, 195 #endif 196 #ifdef CONFIG_KEXEC 197 &kexec_loaded_attr.attr, 198 &kexec_crash_loaded_attr.attr, 199 &kexec_crash_size_attr.attr, 200 &vmcoreinfo_attr.attr, 201 #endif 202 &rcu_expedited_attr.attr, 203 NULL 204 }; 205 206 static struct attribute_group kernel_attr_group = { 207 .attrs = kernel_attrs, 208 }; 209 210 static int __init ksysfs_init(void) 211 { 212 int error; 213 214 kernel_kobj = kobject_create_and_add("kernel", NULL); 215 if (!kernel_kobj) { 216 error = -ENOMEM; 217 goto exit; 218 } 219 error = sysfs_create_group(kernel_kobj, &kernel_attr_group); 220 if (error) 221 goto kset_exit; 222 223 if (notes_size > 0) { 224 notes_attr.size = notes_size; 225 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); 226 if (error) 227 goto group_exit; 228 } 229 230 return 0; 231 232 group_exit: 233 sysfs_remove_group(kernel_kobj, &kernel_attr_group); 234 kset_exit: 235 kobject_put(kernel_kobj); 236 exit: 237 return error; 238 } 239 240 core_initcall(ksysfs_init); 241