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 #include <linux/capability.h> 20 21 #define KERNEL_ATTR_RO(_name) \ 22 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 23 24 #define KERNEL_ATTR_RW(_name) \ 25 static struct kobj_attribute _name##_attr = \ 26 __ATTR(_name, 0644, _name##_show, _name##_store) 27 28 #if defined(CONFIG_HOTPLUG) 29 /* current uevent sequence number */ 30 static ssize_t uevent_seqnum_show(struct kobject *kobj, 31 struct kobj_attribute *attr, char *buf) 32 { 33 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); 34 } 35 KERNEL_ATTR_RO(uevent_seqnum); 36 37 /* uevent helper program, used during early boot */ 38 static ssize_t uevent_helper_show(struct kobject *kobj, 39 struct kobj_attribute *attr, char *buf) 40 { 41 return sprintf(buf, "%s\n", uevent_helper); 42 } 43 static ssize_t uevent_helper_store(struct kobject *kobj, 44 struct kobj_attribute *attr, 45 const char *buf, size_t count) 46 { 47 if (count+1 > UEVENT_HELPER_PATH_LEN) 48 return -ENOENT; 49 memcpy(uevent_helper, buf, count); 50 uevent_helper[count] = '\0'; 51 if (count && uevent_helper[count-1] == '\n') 52 uevent_helper[count-1] = '\0'; 53 return count; 54 } 55 KERNEL_ATTR_RW(uevent_helper); 56 #endif 57 58 #ifdef CONFIG_PROFILING 59 static ssize_t profiling_show(struct kobject *kobj, 60 struct kobj_attribute *attr, char *buf) 61 { 62 return sprintf(buf, "%d\n", prof_on); 63 } 64 static ssize_t profiling_store(struct kobject *kobj, 65 struct kobj_attribute *attr, 66 const char *buf, size_t count) 67 { 68 int ret; 69 70 if (prof_on) 71 return -EEXIST; 72 /* 73 * This eventually calls into get_option() which 74 * has a ton of callers and is not const. It is 75 * easiest to cast it away here. 76 */ 77 profile_setup((char *)buf); 78 ret = profile_init(); 79 if (ret) 80 return ret; 81 ret = create_proc_profile(); 82 if (ret) 83 return ret; 84 return count; 85 } 86 KERNEL_ATTR_RW(profiling); 87 #endif 88 89 #ifdef CONFIG_KEXEC 90 static ssize_t kexec_loaded_show(struct kobject *kobj, 91 struct kobj_attribute *attr, char *buf) 92 { 93 return sprintf(buf, "%d\n", !!kexec_image); 94 } 95 KERNEL_ATTR_RO(kexec_loaded); 96 97 static ssize_t kexec_crash_loaded_show(struct kobject *kobj, 98 struct kobj_attribute *attr, char *buf) 99 { 100 return sprintf(buf, "%d\n", !!kexec_crash_image); 101 } 102 KERNEL_ATTR_RO(kexec_crash_loaded); 103 104 static ssize_t kexec_crash_size_show(struct kobject *kobj, 105 struct kobj_attribute *attr, char *buf) 106 { 107 return sprintf(buf, "%zu\n", crash_get_memory_size()); 108 } 109 static ssize_t kexec_crash_size_store(struct kobject *kobj, 110 struct kobj_attribute *attr, 111 const char *buf, size_t count) 112 { 113 unsigned long cnt; 114 int ret; 115 116 if (strict_strtoul(buf, 0, &cnt)) 117 return -EINVAL; 118 119 ret = crash_shrink_memory(cnt); 120 return ret < 0 ? ret : count; 121 } 122 KERNEL_ATTR_RW(kexec_crash_size); 123 124 static ssize_t vmcoreinfo_show(struct kobject *kobj, 125 struct kobj_attribute *attr, char *buf) 126 { 127 return sprintf(buf, "%lx %x\n", 128 paddr_vmcoreinfo_note(), 129 (unsigned int)vmcoreinfo_max_size); 130 } 131 KERNEL_ATTR_RO(vmcoreinfo); 132 133 #endif /* CONFIG_KEXEC */ 134 135 /* whether file capabilities are enabled */ 136 static ssize_t fscaps_show(struct kobject *kobj, 137 struct kobj_attribute *attr, char *buf) 138 { 139 return sprintf(buf, "%d\n", file_caps_enabled); 140 } 141 KERNEL_ATTR_RO(fscaps); 142 143 /* 144 * Make /sys/kernel/notes give the raw contents of our kernel .notes section. 145 */ 146 extern const void __start_notes __attribute__((weak)); 147 extern const void __stop_notes __attribute__((weak)); 148 #define notes_size (&__stop_notes - &__start_notes) 149 150 static ssize_t notes_read(struct file *filp, struct kobject *kobj, 151 struct bin_attribute *bin_attr, 152 char *buf, loff_t off, size_t count) 153 { 154 memcpy(buf, &__start_notes + off, count); 155 return count; 156 } 157 158 static struct bin_attribute notes_attr = { 159 .attr = { 160 .name = "notes", 161 .mode = S_IRUGO, 162 }, 163 .read = ¬es_read, 164 }; 165 166 struct kobject *kernel_kobj; 167 EXPORT_SYMBOL_GPL(kernel_kobj); 168 169 static struct attribute * kernel_attrs[] = { 170 &fscaps_attr.attr, 171 #if defined(CONFIG_HOTPLUG) 172 &uevent_seqnum_attr.attr, 173 &uevent_helper_attr.attr, 174 #endif 175 #ifdef CONFIG_PROFILING 176 &profiling_attr.attr, 177 #endif 178 #ifdef CONFIG_KEXEC 179 &kexec_loaded_attr.attr, 180 &kexec_crash_loaded_attr.attr, 181 &kexec_crash_size_attr.attr, 182 &vmcoreinfo_attr.attr, 183 #endif 184 NULL 185 }; 186 187 static struct attribute_group kernel_attr_group = { 188 .attrs = kernel_attrs, 189 }; 190 191 static int __init ksysfs_init(void) 192 { 193 int error; 194 195 kernel_kobj = kobject_create_and_add("kernel", NULL); 196 if (!kernel_kobj) { 197 error = -ENOMEM; 198 goto exit; 199 } 200 error = sysfs_create_group(kernel_kobj, &kernel_attr_group); 201 if (error) 202 goto kset_exit; 203 204 if (notes_size > 0) { 205 notes_attr.size = notes_size; 206 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); 207 if (error) 208 goto group_exit; 209 } 210 211 return 0; 212 213 group_exit: 214 sysfs_remove_group(kernel_kobj, &kernel_attr_group); 215 kset_exit: 216 kobject_put(kernel_kobj); 217 exit: 218 return error; 219 } 220 221 core_initcall(ksysfs_init); 222