linux/drivers/base/topology.c
<<
>>
Prefs
   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/init.h>
  27#include <linux/mm.h>
  28#include <linux/cpu.h>
  29#include <linux/module.h>
  30#include <linux/hardirq.h>
  31#include <linux/topology.h>
  32
  33#define define_one_ro_named(_name, _func)                               \
  34        static DEVICE_ATTR(_name, 0444, _func, NULL)
  35
  36#define define_one_ro(_name)                            \
  37        static DEVICE_ATTR(_name, 0444, show_##_name, NULL)
  38
  39#define define_id_show_func(name)                               \
  40static ssize_t show_##name(struct device *dev,                  \
  41                struct device_attribute *attr, char *buf)       \
  42{                                                               \
  43        unsigned int cpu = dev->id;                             \
  44        return sprintf(buf, "%d\n", topology_##name(cpu));      \
  45}
  46
  47#if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \
  48    defined(topology_book_cpumask)
  49static ssize_t show_cpumap(int type, const struct cpumask *mask, char *buf)
  50{
  51        ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
  52        int n = 0;
  53
  54        if (len > 1) {
  55                n = type?
  56                        cpulist_scnprintf(buf, len-2, mask) :
  57                        cpumask_scnprintf(buf, len-2, mask);
  58                buf[n++] = '\n';
  59                buf[n] = '\0';
  60        }
  61        return n;
  62}
  63#endif
  64
  65#ifdef arch_provides_topology_pointers
  66#define define_siblings_show_map(name)                                  \
  67static ssize_t show_##name(struct device *dev,                          \
  68                           struct device_attribute *attr, char *buf)    \
  69{                                                                       \
  70        unsigned int cpu = dev->id;                                     \
  71        return show_cpumap(0, topology_##name(cpu), buf);               \
  72}
  73
  74#define define_siblings_show_list(name)                                 \
  75static ssize_t show_##name##_list(struct device *dev,                   \
  76                                  struct device_attribute *attr,        \
  77                                  char *buf)                            \
  78{                                                                       \
  79        unsigned int cpu = dev->id;                                     \
  80        return show_cpumap(1, topology_##name(cpu), buf);               \
  81}
  82
  83#else
  84#define define_siblings_show_map(name)                                  \
  85static ssize_t show_##name(struct device *dev,                          \
  86                           struct device_attribute *attr, char *buf)    \
  87{                                                                       \
  88        return show_cpumap(0, topology_##name(dev->id), buf);           \
  89}
  90
  91#define define_siblings_show_list(name)                                 \
  92static ssize_t show_##name##_list(struct device *dev,                   \
  93                                  struct device_attribute *attr,        \
  94                                  char *buf)                            \
  95{                                                                       \
  96        return show_cpumap(1, topology_##name(dev->id), buf);           \
  97}
  98#endif
  99
 100#define define_siblings_show_func(name)         \
 101        define_siblings_show_map(name); define_siblings_show_list(name)
 102
 103define_id_show_func(physical_package_id);
 104define_one_ro(physical_package_id);
 105
 106define_id_show_func(core_id);
 107define_one_ro(core_id);
 108
 109define_siblings_show_func(thread_cpumask);
 110define_one_ro_named(thread_siblings, show_thread_cpumask);
 111define_one_ro_named(thread_siblings_list, show_thread_cpumask_list);
 112
 113define_siblings_show_func(core_cpumask);
 114define_one_ro_named(core_siblings, show_core_cpumask);
 115define_one_ro_named(core_siblings_list, show_core_cpumask_list);
 116
 117#ifdef CONFIG_SCHED_BOOK
 118define_id_show_func(book_id);
 119define_one_ro(book_id);
 120define_siblings_show_func(book_cpumask);
 121define_one_ro_named(book_siblings, show_book_cpumask);
 122define_one_ro_named(book_siblings_list, show_book_cpumask_list);
 123#endif
 124
 125static struct attribute *default_attrs[] = {
 126        &dev_attr_physical_package_id.attr,
 127        &dev_attr_core_id.attr,
 128        &dev_attr_thread_siblings.attr,
 129        &dev_attr_thread_siblings_list.attr,
 130        &dev_attr_core_siblings.attr,
 131        &dev_attr_core_siblings_list.attr,
 132#ifdef CONFIG_SCHED_BOOK
 133        &dev_attr_book_id.attr,
 134        &dev_attr_book_siblings.attr,
 135        &dev_attr_book_siblings_list.attr,
 136#endif
 137        NULL
 138};
 139
 140static struct attribute_group topology_attr_group = {
 141        .attrs = default_attrs,
 142        .name = "topology"
 143};
 144
 145/* Add/Remove cpu_topology interface for CPU device */
 146static int topology_add_dev(unsigned int cpu)
 147{
 148        struct device *dev = get_cpu_device(cpu);
 149
 150        return sysfs_create_group(&dev->kobj, &topology_attr_group);
 151}
 152
 153static void topology_remove_dev(unsigned int cpu)
 154{
 155        struct device *dev = get_cpu_device(cpu);
 156
 157        sysfs_remove_group(&dev->kobj, &topology_attr_group);
 158}
 159
 160static int 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 notifier_from_errno(rc);
 179}
 180
 181static int 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
 196device_initcall(topology_sysfs_init);
 197
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.