1 /* 2 * driver/base/topology.c - Populate sysfs with cpu topology information 3 * 4 * Written by: Zhang Yanmin, Intel Corporation 5 * 6 * Copyright (C) 2006, Intel Corp. 7 * 8 * All rights reserved. 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 18 * NON INFRINGEMENT. See the GNU General Public License for more 19 * details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to the Free Software 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 24 * 25 */ 26 #include <linux/init.h> 27 #include <linux/mm.h> 28 #include <linux/cpu.h> 29 #include <linux/module.h> 30 #include <linux/hardirq.h> 31 #include <linux/topology.h> 32 33 #define define_one_ro_named(_name, _func) \ 34 static DEVICE_ATTR(_name, 0444, _func, NULL) 35 36 #define define_one_ro(_name) \ 37 static DEVICE_ATTR(_name, 0444, show_##_name, NULL) 38 39 #define define_id_show_func(name) \ 40 static ssize_t show_##name(struct device *dev, \ 41 struct device_attribute *attr, char *buf) \ 42 { \ 43 unsigned int cpu = dev->id; \ 44 return sprintf(buf, "%d\n", topology_##name(cpu)); \ 45 } 46 47 #if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \ 48 defined(topology_book_cpumask) 49 static ssize_t show_cpumap(int type, const struct cpumask *mask, char *buf) 50 { 51 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; 52 int n = 0; 53 54 if (len > 1) { 55 n = type? 56 cpulist_scnprintf(buf, len-2, mask) : 57 cpumask_scnprintf(buf, len-2, mask); 58 buf[n++] = '\n'; 59 buf[n] = '\0'; 60 } 61 return n; 62 } 63 #endif 64 65 #ifdef arch_provides_topology_pointers 66 #define define_siblings_show_map(name) \ 67 static ssize_t show_##name(struct device *dev, \ 68 struct device_attribute *attr, char *buf) \ 69 { \ 70 unsigned int cpu = dev->id; \ 71 return show_cpumap(0, topology_##name(cpu), buf); \ 72 } 73 74 #define define_siblings_show_list(name) \ 75 static ssize_t show_##name##_list(struct device *dev, \ 76 struct device_attribute *attr, \ 77 char *buf) \ 78 { \ 79 unsigned int cpu = dev->id; \ 80 return show_cpumap(1, topology_##name(cpu), buf); \ 81 } 82 83 #else 84 #define define_siblings_show_map(name) \ 85 static ssize_t show_##name(struct device *dev, \ 86 struct device_attribute *attr, char *buf) \ 87 { \ 88 return show_cpumap(0, topology_##name(dev->id), buf); \ 89 } 90 91 #define define_siblings_show_list(name) \ 92 static ssize_t show_##name##_list(struct device *dev, \ 93 struct device_attribute *attr, \ 94 char *buf) \ 95 { \ 96 return show_cpumap(1, topology_##name(dev->id), buf); \ 97 } 98 #endif 99 100 #define define_siblings_show_func(name) \ 101 define_siblings_show_map(name); define_siblings_show_list(name) 102 103 define_id_show_func(physical_package_id); 104 define_one_ro(physical_package_id); 105 106 define_id_show_func(core_id); 107 define_one_ro(core_id); 108 109 define_siblings_show_func(thread_cpumask); 110 define_one_ro_named(thread_siblings, show_thread_cpumask); 111 define_one_ro_named(thread_siblings_list, show_thread_cpumask_list); 112 113 define_siblings_show_func(core_cpumask); 114 define_one_ro_named(core_siblings, show_core_cpumask); 115 define_one_ro_named(core_siblings_list, show_core_cpumask_list); 116 117 #ifdef CONFIG_SCHED_BOOK 118 define_id_show_func(book_id); 119 define_one_ro(book_id); 120 define_siblings_show_func(book_cpumask); 121 define_one_ro_named(book_siblings, show_book_cpumask); 122 define_one_ro_named(book_siblings_list, show_book_cpumask_list); 123 #endif 124 125 static struct attribute *default_attrs[] = { 126 &dev_attr_physical_package_id.attr, 127 &dev_attr_core_id.attr, 128 &dev_attr_thread_siblings.attr, 129 &dev_attr_thread_siblings_list.attr, 130 &dev_attr_core_siblings.attr, 131 &dev_attr_core_siblings_list.attr, 132 #ifdef CONFIG_SCHED_BOOK 133 &dev_attr_book_id.attr, 134 &dev_attr_book_siblings.attr, 135 &dev_attr_book_siblings_list.attr, 136 #endif 137 NULL 138 }; 139 140 static struct attribute_group topology_attr_group = { 141 .attrs = default_attrs, 142 .name = "topology" 143 }; 144 145 /* Add/Remove cpu_topology interface for CPU device */ 146 static int topology_add_dev(unsigned int cpu) 147 { 148 struct device *dev = get_cpu_device(cpu); 149 150 return sysfs_create_group(&dev->kobj, &topology_attr_group); 151 } 152 153 static void topology_remove_dev(unsigned int cpu) 154 { 155 struct device *dev = get_cpu_device(cpu); 156 157 sysfs_remove_group(&dev->kobj, &topology_attr_group); 158 } 159 160 static int topology_cpu_callback(struct notifier_block *nfb, 161 unsigned long action, void *hcpu) 162 { 163 unsigned int cpu = (unsigned long)hcpu; 164 int rc = 0; 165 166 switch (action) { 167 case CPU_UP_PREPARE: 168 case CPU_UP_PREPARE_FROZEN: 169 rc = topology_add_dev(cpu); 170 break; 171 case CPU_UP_CANCELED: 172 case CPU_UP_CANCELED_FROZEN: 173 case CPU_DEAD: 174 case CPU_DEAD_FROZEN: 175 topology_remove_dev(cpu); 176 break; 177 } 178 return notifier_from_errno(rc); 179 } 180 181 static int topology_sysfs_init(void) 182 { 183 int cpu; 184 int rc; 185 186 for_each_online_cpu(cpu) { 187 rc = topology_add_dev(cpu); 188 if (rc) 189 return rc; 190 } 191 hotcpu_notifier(topology_cpu_callback, 0); 192 193 return 0; 194 } 195 196 device_initcall(topology_sysfs_init); 197