LXR linux/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/mm.h>
  27#include <linux/cpu.h>
  28#include <linux/module.h>
  29#include <linux/hardirq.h>
  30#include <linux/topology.h>
  31
  32#define define_id_show_func(name)                               \
  33static ssize_t name##_show(struct device *dev,                  \
  34                struct device_attribute *attr, char *buf)       \
  35{                                                               \
  36        return sprintf(buf, "%d\n", topology_##name(dev->id));  \
  37}
  38
  39#define define_siblings_show_map(name, mask)                            \
  40static ssize_t name##_show(struct device *dev,                          \
  41                           struct device_attribute *attr, char *buf)    \
  42{                                                                       \
  43        return cpumap_print_to_pagebuf(false, buf, topology_##mask(dev->id));\
  44}
  45
  46#define define_siblings_show_list(name, mask)                           \
  47static ssize_t name##_list_show(struct device *dev,                     \
  48                                struct device_attribute *attr,          \
  49                                char *buf)                              \
  50{                                                                       \
  51        return cpumap_print_to_pagebuf(true, buf, topology_##mask(dev->id));\
  52}
  53
  54#define define_siblings_show_func(name, mask)   \
  55        define_siblings_show_map(name, mask);   \
  56        define_siblings_show_list(name, mask)
  57
  58define_id_show_func(physical_package_id);
  59static DEVICE_ATTR_RO(physical_package_id);
  60
  61define_id_show_func(core_id);
  62static DEVICE_ATTR_RO(core_id);
  63
  64define_siblings_show_func(thread_siblings, sibling_cpumask);
  65static DEVICE_ATTR_RO(thread_siblings);
  66static DEVICE_ATTR_RO(thread_siblings_list);
  67
  68define_siblings_show_func(core_siblings, core_cpumask);
  69static DEVICE_ATTR_RO(core_siblings);
  70static DEVICE_ATTR_RO(core_siblings_list);
  71
  72#ifdef CONFIG_SCHED_BOOK
  73define_id_show_func(book_id);
  74static DEVICE_ATTR_RO(book_id);
  75define_siblings_show_func(book_siblings, book_cpumask);
  76static DEVICE_ATTR_RO(book_siblings);
  77static DEVICE_ATTR_RO(book_siblings_list);
  78#endif
  79
  80static struct attribute *default_attrs[] = {
  81        &dev_attr_physical_package_id.attr,
  82        &dev_attr_core_id.attr,
  83        &dev_attr_thread_siblings.attr,
  84        &dev_attr_thread_siblings_list.attr,
  85        &dev_attr_core_siblings.attr,
  86        &dev_attr_core_siblings_list.attr,
  87#ifdef CONFIG_SCHED_BOOK
  88        &dev_attr_book_id.attr,
  89        &dev_attr_book_siblings.attr,
  90        &dev_attr_book_siblings_list.attr,
  91#endif
  92        NULL
  93};
  94
  95static struct attribute_group topology_attr_group = {
  96        .attrs = default_attrs,
  97        .name = "topology"
  98};
  99
 100/* Add/Remove cpu_topology interface for CPU device */
 101static int topology_add_dev(unsigned int cpu)
 102{
 103        struct device *dev = get_cpu_device(cpu);
 104
 105        return sysfs_create_group(&dev->kobj, &topology_attr_group);
 106}
 107
 108static void topology_remove_dev(unsigned int cpu)
 109{
 110        struct device *dev = get_cpu_device(cpu);
 111
 112        sysfs_remove_group(&dev->kobj, &topology_attr_group);
 113}
 114
 115static int topology_cpu_callback(struct notifier_block *nfb,
 116                                 unsigned long action, void *hcpu)
 117{
 118        unsigned int cpu = (unsigned long)hcpu;
 119        int rc = 0;
 120
 121        switch (action) {
 122        case CPU_UP_PREPARE:
 123        case CPU_UP_PREPARE_FROZEN:
 124                rc = topology_add_dev(cpu);
 125                break;
 126        case CPU_UP_CANCELED:
 127        case CPU_UP_CANCELED_FROZEN:
 128        case CPU_DEAD:
 129        case CPU_DEAD_FROZEN:
 130                topology_remove_dev(cpu);
 131                break;
 132        }
 133        return notifier_from_errno(rc);
 134}
 135
 136static int topology_sysfs_init(void)
 137{
 138        int cpu;
 139        int rc = 0;
 140
 141        cpu_notifier_register_begin();
 142
 143        for_each_online_cpu(cpu) {
 144                rc = topology_add_dev(cpu);
 145                if (rc)
 146                        goto out;
 147        }
 148        __hotcpu_notifier(topology_cpu_callback, 0);
 149
 150out:
 151        cpu_notifier_register_done();
 152        return rc;
 153}
 154
 155device_initcall(topology_sysfs_init);
 156