| 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); |