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); 212