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_id_show_func(name)                               \
  33 static ssize_t name##_show(struct device *dev,                  \
  34                 struct device_attribute *attr, char *buf)       \
  35 {                                                               \
  36         return sprintf(buf, "%d\n", topology_##name(dev->id));  \
  37 }
  38
  39 #define define_siblings_show_map(name, mask)                            \
  40 static ssize_t name##_show(struct device *dev,                          \
  41                            struct device_attribute *attr, char *buf)    \
  42 {                                                                       \
  43         return cpumap_print_to_pagebuf(false, buf, topology_##mask(dev->id));\
  44 }
  45
  46 #define define_siblings_show_list(name, mask)                           \
  47 static ssize_t name##_list_show(struct device *dev,                     \
  48                                 struct device_attribute *attr,          \
  49                                 char *buf)                              \
  50 {                                                                       \
  51         return cpumap_print_to_pagebuf(true, buf, topology_##mask(dev->id));\
  52 }
  53
  54 #define define_siblings_show_func(name, mask)   \
  55         define_siblings_show_map(name, mask);   \
  56         define_siblings_show_list(name, mask)
  57
  58 define_id_show_func(physical_package_id);
  59 static DEVICE_ATTR_RO(physical_package_id);
  60
  61 define_id_show_func(core_id);
  62 static DEVICE_ATTR_RO(core_id);
  63
  64 define_siblings_show_func(thread_siblings, sibling_cpumask);
  65 static DEVICE_ATTR_RO(thread_siblings);
  66 static DEVICE_ATTR_RO(thread_siblings_list);
  67
  68 define_siblings_show_func(core_siblings, core_cpumask);
  69 static DEVICE_ATTR_RO(core_siblings);
  70 static DEVICE_ATTR_RO(core_siblings_list);
  71
  72 #ifdef CONFIG_SCHED_BOOK
  73 define_id_show_func(book_id);
  74 static DEVICE_ATTR_RO(book_id);
  75 define_siblings_show_func(book_siblings, book_cpumask);
  76 static DEVICE_ATTR_RO(book_siblings);
  77 static DEVICE_ATTR_RO(book_siblings_list);
  78 #endif
  79
  80 static struct attribute *default_attrs[] = {
  81         &dev_attr_physical_package_id.attr,
  82         &dev_attr_core_id.attr,
  83         &dev_attr_thread_siblings.attr,
  84         &dev_attr_thread_siblings_list.attr,
  85         &dev_attr_core_siblings.attr,
  86         &dev_attr_core_siblings_list.attr,
  87 #ifdef CONFIG_SCHED_BOOK
  88         &dev_attr_book_id.attr,
  89         &dev_attr_book_siblings.attr,
  90         &dev_attr_book_siblings_list.attr,
  91 #endif
  92         NULL
  93 };
  94
  95 static struct attribute_group topology_attr_group = {
  96         .attrs = default_attrs,
  97         .name = "topology"
  98 };
  99
 100 /* Add/Remove cpu_topology interface for CPU device */
 101 static int topology_add_dev(unsigned int cpu)
 102 {
 103         struct device *dev = get_cpu_device(cpu);
 104
 105         return sysfs_create_group(&dev->kobj, &topology_attr_group);
 106 }
 107
 108 static void topology_remove_dev(unsigned int cpu)
 109 {
 110         struct device *dev = get_cpu_device(cpu);
 111
 112         sysfs_remove_group(&dev->kobj, &topology_attr_group);
 113 }
 114
 115 static int topology_cpu_callback(struct notifier_block *nfb,
 116                                  unsigned long action, void *hcpu)
 117 {
 118         unsigned int cpu = (unsigned long)hcpu;
 119         int rc = 0;
 120
 121         switch (action) {
 122         case CPU_UP_PREPARE:
 123         case CPU_UP_PREPARE_FROZEN:
 124                 rc = topology_add_dev(cpu);
 125                 break;
 126         case CPU_UP_CANCELED:
 127         case CPU_UP_CANCELED_FROZEN:
 128         case CPU_DEAD:
 129         case CPU_DEAD_FROZEN:
 130                 topology_remove_dev(cpu);
 131                 break;
 132         }
 133         return notifier_from_errno(rc);
 134 }
 135
 136 static int topology_sysfs_init(void)
 137 {
 138         int cpu;
 139         int rc = 0;
 140
 141         cpu_notifier_register_begin();
 142
 143         for_each_online_cpu(cpu) {
 144                 rc = topology_add_dev(cpu);
 145                 if (rc)
 146                         goto out;
 147         }
 148         __hotcpu_notifier(topology_cpu_callback, 0);
 149
 150 out:
 151         cpu_notifier_register_done();
 152         return rc;
 153 }
 154
 155 device_initcall(topology_sysfs_init);