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/mm.h> 27 #include <linux/cpu.h> 28 #include <linux/module.h> 29 #include <linux/hardirq.h> 30 #include <linux/topology.h> 31 32 #define define_one_ro_named(_name, _func) \ 33 static DEVICE_ATTR(_name, 0444, _func, NULL) 34 35 #define define_one_ro(_name) \ 36 static DEVICE_ATTR(_name, 0444, show_##_name, NULL) 37 38 #define define_id_show_func(name) \ 39 static ssize_t show_##name(struct device *dev, \ 40 struct device_attribute *attr, char *buf) \ 41 { \ 42 return sprintf(buf, "%d\n", topology_##name(dev->id)); \ 43 } 44 45 #if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \ 46 defined(topology_book_cpumask) 47 static ssize_t show_cpumap(int type, const struct cpumask *mask, char *buf) 48 { 49 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; 50 int n = 0; 51 52 if (len > 1) { 53 n = type? 54 cpulist_scnprintf(buf, len-2, mask) : 55 cpumask_scnprintf(buf, len-2, mask); 56 buf[n++] = '\n'; 57 buf[n] = '\0'; 58 } 59 return n; 60 } 61 #endif 62 63 #define define_siblings_show_map(name) \ 64 static ssize_t show_##name(struct device *dev, \ 65 struct device_attribute *attr, char *buf) \ 66 { \ 67 return show_cpumap(0, topology_##name(dev->id), buf); \ 68 } 69 70 #define define_siblings_show_list(name) \ 71 static ssize_t show_##name##_list(struct device *dev, \ 72 struct device_attribute *attr, \ 73 char *buf) \ 74 { \ 75 return show_cpumap(1, topology_##name(dev->id), buf); \ 76 } 77 78 #define define_siblings_show_func(name) \ 79 define_siblings_show_map(name); define_siblings_show_list(name) 80 81 define_id_show_func(physical_package_id); 82 define_one_ro(physical_package_id); 83 84 define_id_show_func(core_id); 85 define_one_ro(core_id); 86 87 define_siblings_show_func(thread_cpumask); 88 define_one_ro_named(thread_siblings, show_thread_cpumask); 89 define_one_ro_named(thread_siblings_list, show_thread_cpumask_list); 90 91 define_siblings_show_func(core_cpumask); 92 define_one_ro_named(core_siblings, show_core_cpumask); 93 define_one_ro_named(core_siblings_list, show_core_cpumask_list); 94 95 #ifdef CONFIG_SCHED_BOOK 96 define_id_show_func(book_id); 97 define_one_ro(book_id); 98 define_siblings_show_func(book_cpumask); 99 define_one_ro_named(book_siblings, show_book_cpumask); 100 define_one_ro_named(book_siblings_list, show_book_cpumask_list); 101 #endif 102 103 static struct attribute *default_attrs[] = { 104 &dev_attr_physical_package_id.attr, 105 &dev_attr_core_id.attr, 106 &dev_attr_thread_siblings.attr, 107 &dev_attr_thread_siblings_list.attr, 108 &dev_attr_core_siblings.attr, 109 &dev_attr_core_siblings_list.attr, 110 #ifdef CONFIG_SCHED_BOOK 111 &dev_attr_book_id.attr, 112 &dev_attr_book_siblings.attr, 113 &dev_attr_book_siblings_list.attr, 114 #endif 115 NULL 116 }; 117 118 static struct attribute_group topology_attr_group = { 119 .attrs = default_attrs, 120 .name = "topology" 121 }; 122 123 /* Add/Remove cpu_topology interface for CPU device */ 124 static int topology_add_dev(unsigned int cpu) 125 { 126 struct device *dev = get_cpu_device(cpu); 127 128 return sysfs_create_group(&dev->kobj, &topology_attr_group); 129 } 130 131 static void topology_remove_dev(unsigned int cpu) 132 { 133 struct device *dev = get_cpu_device(cpu); 134 135 sysfs_remove_group(&dev->kobj, &topology_attr_group); 136 } 137 138 static int topology_cpu_callback(struct notifier_block *nfb, 139 unsigned long action, void *hcpu) 140 { 141 unsigned int cpu = (unsigned long)hcpu; 142 int rc = 0; 143 144 switch (action) { 145 case CPU_UP_PREPARE: 146 case CPU_UP_PREPARE_FROZEN: 147 rc = topology_add_dev(cpu); 148 break; 149 case CPU_UP_CANCELED: 150 case CPU_UP_CANCELED_FROZEN: 151 case CPU_DEAD: 152 case CPU_DEAD_FROZEN: 153 topology_remove_dev(cpu); 154 break; 155 } 156 return notifier_from_errno(rc); 157 } 158 159 static int topology_sysfs_init(void) 160 { 161 int cpu; 162 int rc = 0; 163 164 cpu_notifier_register_begin(); 165 166 for_each_online_cpu(cpu) { 167 rc = topology_add_dev(cpu); 168 if (rc) 169 goto out; 170 } 171 __hotcpu_notifier(topology_cpu_callback, 0); 172 173 out: 174 cpu_notifier_register_done(); 175 return rc; 176 } 177 178 device_initcall(topology_sysfs_init); 179