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