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 unsigned int cpu = dev->id; \ 43 return sprintf(buf, "%d\n", topology_##name(cpu)); \ 44 } 45 46 #if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \ 47 defined(topology_book_cpumask) 48 static ssize_t show_cpumap(int type, const struct cpumask *mask, char *buf) 49 { 50 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; 51 int n = 0; 52 53 if (len > 1) { 54 n = type? 55 cpulist_scnprintf(buf, len-2, mask) : 56 cpumask_scnprintf(buf, len-2, mask); 57 buf[n++] = '\n'; 58 buf[n] = '\0'; 59 } 60 return n; 61 } 62 #endif 63 64 #define define_siblings_show_map(name) \ 65 static ssize_t show_##name(struct device *dev, \ 66 struct device_attribute *attr, char *buf) \ 67 { \ 68 return show_cpumap(0, topology_##name(dev->id), buf); \ 69 } 70 71 #define define_siblings_show_list(name) \ 72 static ssize_t show_##name##_list(struct device *dev, \ 73 struct device_attribute *attr, \ 74 char *buf) \ 75 { \ 76 return show_cpumap(1, topology_##name(dev->id), buf); \ 77 } 78 79 #define define_siblings_show_func(name) \ 80 define_siblings_show_map(name); define_siblings_show_list(name) 81 82 define_id_show_func(physical_package_id); 83 define_one_ro(physical_package_id); 84 85 define_id_show_func(core_id); 86 define_one_ro(core_id); 87 88 define_siblings_show_func(thread_cpumask); 89 define_one_ro_named(thread_siblings, show_thread_cpumask); 90 define_one_ro_named(thread_siblings_list, show_thread_cpumask_list); 91 92 define_siblings_show_func(core_cpumask); 93 define_one_ro_named(core_siblings, show_core_cpumask); 94 define_one_ro_named(core_siblings_list, show_core_cpumask_list); 95 96 #ifdef CONFIG_SCHED_BOOK 97 define_id_show_func(book_id); 98 define_one_ro(book_id); 99 define_siblings_show_func(book_cpumask); 100 define_one_ro_named(book_siblings, show_book_cpumask); 101 define_one_ro_named(book_siblings_list, show_book_cpumask_list); 102 #endif 103 104 static struct attribute *default_attrs[] = { 105 &dev_attr_physical_package_id.attr, 106 &dev_attr_core_id.attr, 107 &dev_attr_thread_siblings.attr, 108 &dev_attr_thread_siblings_list.attr, 109 &dev_attr_core_siblings.attr, 110 &dev_attr_core_siblings_list.attr, 111 #ifdef CONFIG_SCHED_BOOK 112 &dev_attr_book_id.attr, 113 &dev_attr_book_siblings.attr, 114 &dev_attr_book_siblings_list.attr, 115 #endif 116 NULL 117 }; 118 119 static struct attribute_group topology_attr_group = { 120 .attrs = default_attrs, 121 .name = "topology" 122 }; 123 124 /* Add/Remove cpu_topology interface for CPU device */ 125 static int topology_add_dev(unsigned int cpu) 126 { 127 struct device *dev = get_cpu_device(cpu); 128 129 return sysfs_create_group(&dev->kobj, &topology_attr_group); 130 } 131 132 static void topology_remove_dev(unsigned int cpu) 133 { 134 struct device *dev = get_cpu_device(cpu); 135 136 sysfs_remove_group(&dev->kobj, &topology_attr_group); 137 } 138 139 static int topology_cpu_callback(struct notifier_block *nfb, 140 unsigned long action, void *hcpu) 141 { 142 unsigned int cpu = (unsigned long)hcpu; 143 int rc = 0; 144 145 switch (action) { 146 case CPU_UP_PREPARE: 147 case CPU_UP_PREPARE_FROZEN: 148 rc = topology_add_dev(cpu); 149 break; 150 case CPU_UP_CANCELED: 151 case CPU_UP_CANCELED_FROZEN: 152 case CPU_DEAD: 153 case CPU_DEAD_FROZEN: 154 topology_remove_dev(cpu); 155 break; 156 } 157 return notifier_from_errno(rc); 158 } 159 160 static int topology_sysfs_init(void) 161 { 162 int cpu; 163 int rc = 0; 164 165 cpu_notifier_register_begin(); 166 167 for_each_online_cpu(cpu) { 168 rc = topology_add_dev(cpu); 169 if (rc) 170 goto out; 171 } 172 __hotcpu_notifier(topology_cpu_callback, 0); 173 174 out: 175 cpu_notifier_register_done(); 176 return rc; 177 } 178 179 device_initcall(topology_sysfs_init); 180