arch/x86/kernel/topology.c

   1 /*
   2  * arch/i386/kernel/topology.c - Populate sysfs with topology information
   3  *
   4  * Written by: Matthew Dobson, IBM Corporation
   5  * Original Code: Paul Dorwin, IBM Corporation, Patrick Mochel, OSDL
   6  *
   7  * Copyright (C) 2002, IBM Corp.
   8  *
   9  * All rights reserved.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  19  * NON INFRINGEMENT.  See the GNU General Public License for more
  20  * details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  *
  26  * Send feedback to <colpatch@us.ibm.com>
  27  */
  28 #include <linux/init.h>
  29 #include <linux/smp.h>
  30 #include <linux/nodemask.h>
  31 #include <linux/mmzone.h>
  32 #include <asm/cpu.h>
  33
  34 static struct i386_cpu cpu_devices[NR_CPUS];
  35
  36 int arch_register_cpu(int num)
  37 {
  38         /*
  39          * CPU0 cannot be offlined due to several
  40          * restrictions and assumptions in kernel. This basically
  41          * doesnt add a control file, one cannot attempt to offline
  42          * BSP.
  43          *
  44          * Also certain PCI quirks require not to enable hotplug control
  45          * for all CPU's.
  46          */
  47         if (num && enable_cpu_hotplug)
  48                 cpu_devices[num].cpu.hotpluggable = 1;
  49
  50         return register_cpu(&cpu_devices[num].cpu, num);
  51 }
  52
  53 #ifdef CONFIG_HOTPLUG_CPU
  54 int enable_cpu_hotplug = 1;
  55
  56 void arch_unregister_cpu(int num) {
  57         return unregister_cpu(&cpu_devices[num].cpu);
  58 }
  59 EXPORT_SYMBOL(arch_register_cpu);
  60 EXPORT_SYMBOL(arch_unregister_cpu);
  61 #endif /*CONFIG_HOTPLUG_CPU*/
  62
  63 static int __init topology_init(void)
  64 {
  65         int i;
  66
  67 #ifdef CONFIG_NUMA
  68         for_each_online_node(i)
  69                 register_one_node(i);
  70 #endif /* CONFIG_NUMA */
  71
  72         for_each_present_cpu(i)
  73                 arch_register_cpu(i);
  74         return 0;
  75 }
  76
  77 subsys_initcall(topology_init);