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