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