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