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/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);