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/config.h> 12 #include <linux/kobject.h> 13 #include <linux/string.h> 14 #include <linux/sysfs.h> 15 #include <linux/module.h> 16 #include <linux/init.h> 17 18 #define KERNEL_ATTR_RO(_name) \ 19 static struct subsys_attribute _name##_attr = __ATTR_RO(_name) 20 21 #define KERNEL_ATTR_RW(_name) \ 22 static struct subsys_attribute _name##_attr = \ 23 __ATTR(_name, 0644, _name##_show, _name##_store) 24 25 #ifdef CONFIG_HOTPLUG 26 static ssize_t hotplug_seqnum_show(struct subsystem *subsys, char *page) 27 { 28 return sprintf(page, "%llu\n", (unsigned long long)hotplug_seqnum); 29 } 30 KERNEL_ATTR_RO(hotplug_seqnum); 31 #endif 32 33 #ifdef CONFIG_KEXEC 34 #include <asm/kexec.h> 35 36 static ssize_t crash_notes_show(struct subsystem *subsys, char *page) 37 { 38 return sprintf(page, "%p\n", (void *)crash_notes); 39 } 40 KERNEL_ATTR_RO(crash_notes); 41 #endif 42 43 decl_subsys(kernel, NULL, NULL); 44 EXPORT_SYMBOL_GPL(kernel_subsys); 45 46 static struct attribute * kernel_attrs[] = { 47 #ifdef CONFIG_HOTPLUG 48 &hotplug_seqnum_attr.attr, 49 #endif 50 #ifdef CONFIG_KEXEC 51 &crash_notes_attr.attr, 52 #endif 53 NULL 54 }; 55 56 static struct attribute_group kernel_attr_group = { 57 .attrs = kernel_attrs, 58 }; 59 60 static int __init ksysfs_init(void) 61 { 62 int error = subsystem_register(&kernel_subsys); 63 if (!error) 64 error = sysfs_create_group(&kernel_subsys.kset.kobj, 65 &kernel_attr_group); 66 67 return error; 68 } 69 70 core_initcall(ksysfs_init); 71