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