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 #ifdef CONFIG_SCHED_DRAWER
  81 define_id_show_func(drawer_id);
  82 static DEVICE_ATTR_RO(drawer_id);
  83 define_siblings_show_func(drawer_siblings, drawer_cpumask);
  84 static DEVICE_ATTR_RO(drawer_siblings);
  85 static DEVICE_ATTR_RO(drawer_siblings_list);
  86 #endif
  87
  88 static struct attribute *default_attrs[] = {
  89         &dev_attr_physical_package_id.attr,
  90         &dev_attr_core_id.attr,
  91         &dev_attr_thread_siblings.attr,
  92         &dev_attr_thread_siblings_list.attr,
  93         &dev_attr_core_siblings.attr,
  94         &dev_attr_core_siblings_list.attr,
  95 #ifdef CONFIG_SCHED_BOOK
  96         &dev_attr_book_id.attr,
  97         &dev_attr_book_siblings.attr,
  98         &dev_attr_book_siblings_list.attr,
  99 #endif
 100 #ifdef CONFIG_SCHED_DRAWER
 101         &dev_attr_drawer_id.attr,
 102         &dev_attr_drawer_siblings.attr,
 103         &dev_attr_drawer_siblings_list.attr,
 104 #endif
 105         NULL
 106 };
 107
 108 static struct attribute_group topology_attr_group = {
 109         .attrs = default_attrs,
 110         .name = "topology"
 111 };
 112
 113 /* Add/Remove cpu_topology interface for CPU device */
 114 static int topology_add_dev(unsigned int cpu)
 115 {
 116         struct device *dev = get_cpu_device(cpu);
 117
 118         return sysfs_create_group(&dev->kobj, &topology_attr_group);
 119 }
 120
 121 static void topology_remove_dev(unsigned int cpu)
 122 {
 123         struct device *dev = get_cpu_device(cpu);
 124
 125         sysfs_remove_group(&dev->kobj, &topology_attr_group);
 126 }
 127
 128 static int topology_cpu_callback(struct notifier_block *nfb,
 129                                  unsigned long action, void *hcpu)
 130 {
 131         unsigned int cpu = (unsigned long)hcpu;
 132         int rc = 0;
 133
 134         switch (action) {
 135         case CPU_UP_PREPARE:
 136         case CPU_UP_PREPARE_FROZEN:
 137                 rc = topology_add_dev(cpu);
 138                 break;
 139         case CPU_UP_CANCELED:
 140         case CPU_UP_CANCELED_FROZEN:
 141         case CPU_DEAD:
 142         case CPU_DEAD_FROZEN:
 143                 topology_remove_dev(cpu);
 144                 break;
 145         }
 146         return notifier_from_errno(rc);
 147 }
 148
 149 static int topology_sysfs_init(void)
 150 {
 151         int cpu;
 152         int rc = 0;
 153
 154         cpu_notifier_register_begin();
 155
 156         for_each_online_cpu(cpu) {
 157                 rc = topology_add_dev(cpu);
 158                 if (rc)
 159                         goto out;
 160         }
 161         __hotcpu_notifier(topology_cpu_callback, 0);
 162
 163 out:
 164         cpu_notifier_register_done();
 165         return rc;
 166 }
 167
 168 device_initcall(topology_sysfs_init);