drivers/base/topology.c

   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         return sprintf(buf, "%d\n", topology_##name(dev->id));  \
  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 #ifdef arch_provides_topology_pointers
  65 #define define_siblings_show_map(name)                                  \
  66 static ssize_t show_##name(struct device *dev,                          \
  67                            struct device_attribute *attr, char *buf)    \
  68 {                                                                       \
  69         unsigned int cpu = dev->id;                                     \
  70         return show_cpumap(0, topology_##name(cpu), buf);               \
  71 }
  72
  73 #define define_siblings_show_list(name)                                 \
  74 static ssize_t show_##name##_list(struct device *dev,                   \
  75                                   struct device_attribute *attr,        \
  76                                   char *buf)                            \
  77 {                                                                       \
  78         unsigned int cpu = dev->id;                                     \
  79         return show_cpumap(1, topology_##name(cpu), buf);               \
  80 }
  81
  82 #else
  83 #define define_siblings_show_map(name)                                  \
  84 static ssize_t show_##name(struct device *dev,                          \
  85                            struct device_attribute *attr, char *buf)    \
  86 {                                                                       \
  87         return show_cpumap(0, topology_##name(dev->id), buf);           \
  88 }
  89
  90 #define define_siblings_show_list(name)                                 \
  91 static ssize_t show_##name##_list(struct device *dev,                   \
  92                                   struct device_attribute *attr,        \
  93                                   char *buf)                            \
  94 {                                                                       \
  95         return show_cpumap(1, topology_##name(dev->id), buf);           \
  96 }
  97 #endif
  98
  99 #define define_siblings_show_func(name)         \
 100         define_siblings_show_map(name); define_siblings_show_list(name)
 101
 102 define_id_show_func(physical_package_id);
 103 define_one_ro(physical_package_id);
 104
 105 define_id_show_func(core_id);
 106 define_one_ro(core_id);
 107
 108 define_siblings_show_func(thread_cpumask);
 109 define_one_ro_named(thread_siblings, show_thread_cpumask);
 110 define_one_ro_named(thread_siblings_list, show_thread_cpumask_list);
 111
 112 define_siblings_show_func(core_cpumask);
 113 define_one_ro_named(core_siblings, show_core_cpumask);
 114 define_one_ro_named(core_siblings_list, show_core_cpumask_list);
 115
 116 #ifdef CONFIG_SCHED_BOOK
 117 define_id_show_func(book_id);
 118 define_one_ro(book_id);
 119 define_siblings_show_func(book_cpumask);
 120 define_one_ro_named(book_siblings, show_book_cpumask);
 121 define_one_ro_named(book_siblings_list, show_book_cpumask_list);
 122 #endif
 123
 124 static struct attribute *default_attrs[] = {
 125         &dev_attr_physical_package_id.attr,
 126         &dev_attr_core_id.attr,
 127         &dev_attr_thread_siblings.attr,
 128         &dev_attr_thread_siblings_list.attr,
 129         &dev_attr_core_siblings.attr,
 130         &dev_attr_core_siblings_list.attr,
 131 #ifdef CONFIG_SCHED_BOOK
 132         &dev_attr_book_id.attr,
 133         &dev_attr_book_siblings.attr,
 134         &dev_attr_book_siblings_list.attr,
 135 #endif
 136         NULL
 137 };
 138
 139 static struct attribute_group topology_attr_group = {
 140         .attrs = default_attrs,
 141         .name = "topology"
 142 };
 143
 144 /* Add/Remove cpu_topology interface for CPU device */
 145 static int __cpuinit topology_add_dev(unsigned int cpu)
 146 {
 147         struct device *dev = get_cpu_device(cpu);
 148
 149         return sysfs_create_group(&dev->kobj, &topology_attr_group);
 150 }
 151
 152 static void __cpuinit topology_remove_dev(unsigned int cpu)
 153 {
 154         struct device *dev = get_cpu_device(cpu);
 155
 156         sysfs_remove_group(&dev->kobj, &topology_attr_group);
 157 }
 158
 159 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
 160                                            unsigned long action, void *hcpu)
 161 {
 162         unsigned int cpu = (unsigned long)hcpu;
 163         int rc = 0;
 164
 165         switch (action) {
 166         case CPU_UP_PREPARE:
 167         case CPU_UP_PREPARE_FROZEN:
 168                 rc = topology_add_dev(cpu);
 169                 break;
 170         case CPU_UP_CANCELED:
 171         case CPU_UP_CANCELED_FROZEN:
 172         case CPU_DEAD:
 173         case CPU_DEAD_FROZEN:
 174                 topology_remove_dev(cpu);
 175                 break;
 176         }
 177         return notifier_from_errno(rc);
 178 }
 179
 180 static int __cpuinit topology_sysfs_init(void)
 181 {
 182         int cpu;
 183         int rc;
 184
 185         for_each_online_cpu(cpu) {
 186                 rc = topology_add_dev(cpu);
 187                 if (rc)
 188                         return rc;
 189         }
 190         hotcpu_notifier(topology_cpu_callback, 0);
 191
 192         return 0;
 193 }
 194
 195 device_initcall(topology_sysfs_init);