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