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/sysdev.h>
  27 #include <linux/init.h>
  28 #include <linux/mm.h>
  29 #include <linux/cpu.h>
  30 #include <linux/module.h>
  31 #include <linux/topology.h>
  32
  33 #define define_one_ro(_name)            \
  34 static SYSDEV_ATTR(_name, 0444, show_##_name, NULL)
  35
  36 #define define_id_show_func(name)                               \
  37 static ssize_t show_##name(struct sys_device *dev, char *buf)   \
  38 {                                                               \
  39         unsigned int cpu = dev->id;                             \
  40         return sprintf(buf, "%d\n", topology_##name(cpu));      \
  41 }
  42
  43 #if defined(topology_thread_siblings) || defined(topology_core_siblings)
  44 static ssize_t show_cpumap(int type, cpumask_t *mask, char *buf)
  45 {
  46         ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
  47         int n = 0;
  48
  49         if (len > 1) {
  50                 n = type?
  51                         cpulist_scnprintf(buf, len-2, *mask):
  52                         cpumask_scnprintf(buf, len-2, *mask);
  53                 buf[n++] = '\n';
  54                 buf[n] = '\0';
  55         }
  56         return n;
  57 }
  58 #endif
  59
  60 #ifdef arch_provides_topology_pointers
  61 #define define_siblings_show_map(name)                                  \
  62 static ssize_t show_##name(struct sys_device *dev, char *buf)   \
  63 {                                                                       \
  64         unsigned int cpu = dev->id;                                     \
  65         return show_cpumap(0, &(topology_##name(cpu)), buf);            \
  66 }
  67
  68 #define define_siblings_show_list(name)                                 \
  69 static ssize_t show_##name##_list(struct sys_device *dev, char *buf) \
  70 {                                                                       \
  71         unsigned int cpu = dev->id;                                     \
  72         return show_cpumap(1, &(topology_##name(cpu)), buf);            \
  73 }
  74
  75 #else
  76 #define define_siblings_show_map(name)                                  \
  77 static ssize_t show_##name(struct sys_device *dev, char *buf)   \
  78 {                                                                       \
  79         unsigned int cpu = dev->id;                                     \
  80         cpumask_t mask = topology_##name(cpu);                          \
  81         return show_cpumap(0, &mask, buf);                              \
  82 }
  83
  84 #define define_siblings_show_list(name)                                 \
  85 static ssize_t show_##name##_list(struct sys_device *dev, char *buf) \
  86 {                                                                       \
  87         unsigned int cpu = dev->id;                                     \
  88         cpumask_t mask = topology_##name(cpu);                          \
  89         return show_cpumap(1, &mask, buf);                              \
  90 }
  91 #endif
  92
  93 #define define_siblings_show_func(name)         \
  94         define_siblings_show_map(name); define_siblings_show_list(name)
  95
  96 #ifdef  topology_physical_package_id
  97 define_id_show_func(physical_package_id);
  98 define_one_ro(physical_package_id);
  99 #define ref_physical_package_id_attr    &attr_physical_package_id.attr,
 100 #else
 101 #define ref_physical_package_id_attr
 102 #endif
 103
 104 #ifdef topology_core_id
 105 define_id_show_func(core_id);
 106 define_one_ro(core_id);
 107 #define ref_core_id_attr                &attr_core_id.attr,
 108 #else
 109 #define ref_core_id_attr
 110 #endif
 111
 112 #ifdef topology_thread_siblings
 113 define_siblings_show_func(thread_siblings);
 114 define_one_ro(thread_siblings);
 115 define_one_ro(thread_siblings_list);
 116 #define ref_thread_siblings_attr        \
 117                 &attr_thread_siblings.attr, &attr_thread_siblings_list.attr,
 118 #else
 119 #define ref_thread_siblings_attr
 120 #endif
 121
 122 #ifdef topology_core_siblings
 123 define_siblings_show_func(core_siblings);
 124 define_one_ro(core_siblings);
 125 define_one_ro(core_siblings_list);
 126 #define ref_core_siblings_attr          \
 127                 &attr_core_siblings.attr, &attr_core_siblings_list.attr,
 128 #else
 129 #define ref_core_siblings_attr
 130 #endif
 131
 132 static struct attribute *default_attrs[] = {
 133         ref_physical_package_id_attr
 134         ref_core_id_attr
 135         ref_thread_siblings_attr
 136         ref_core_siblings_attr
 137         NULL
 138 };
 139
 140 static struct attribute_group topology_attr_group = {
 141         .attrs = default_attrs,
 142         .name = "topology"
 143 };
 144
 145 /* Add/Remove cpu_topology interface for CPU device */
 146 static int __cpuinit topology_add_dev(unsigned int cpu)
 147 {
 148         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 149
 150         return sysfs_create_group(&sys_dev->kobj, &topology_attr_group);
 151 }
 152
 153 static void __cpuinit topology_remove_dev(unsigned int cpu)
 154 {
 155         struct sys_device *sys_dev = get_cpu_sysdev(cpu);
 156
 157         sysfs_remove_group(&sys_dev->kobj, &topology_attr_group);
 158 }
 159
 160 static int __cpuinit topology_cpu_callback(struct notifier_block *nfb,
 161                                            unsigned long action, void *hcpu)
 162 {
 163         unsigned int cpu = (unsigned long)hcpu;
 164         int rc = 0;
 165
 166         switch (action) {
 167         case CPU_UP_PREPARE:
 168         case CPU_UP_PREPARE_FROZEN:
 169                 rc = topology_add_dev(cpu);
 170                 break;
 171         case CPU_UP_CANCELED:
 172         case CPU_UP_CANCELED_FROZEN:
 173         case CPU_DEAD:
 174         case CPU_DEAD_FROZEN:
 175                 topology_remove_dev(cpu);
 176                 break;
 177         }
 178         return rc ? NOTIFY_BAD : NOTIFY_OK;
 179 }
 180
 181 static int __cpuinit topology_sysfs_init(void)
 182 {
 183         int cpu;
 184         int rc;
 185
 186         for_each_online_cpu(cpu) {
 187                 rc = topology_add_dev(cpu);
 188                 if (rc)
 189                         return rc;
 190         }
 191         hotcpu_notifier(topology_cpu_callback, 0);
 192
 193         return 0;
 194 }
 195
 196 device_initcall(topology_sysfs_init);