xref: /openbmc/linux/arch/x86/kernel/topology.c (revision b5266ea6)
1 /*
2  * 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/nodemask.h>
29 #include <linux/export.h>
30 #include <linux/mmzone.h>
31 #include <linux/init.h>
32 #include <linux/smp.h>
33 #include <asm/cpu.h>
34 
35 static DEFINE_PER_CPU(struct x86_cpu, cpu_devices);
36 
37 #ifdef CONFIG_HOTPLUG_CPU
38 int __ref arch_register_cpu(int num)
39 {
40 	/*
41 	 * CPU0 cannot be offlined due to several
42 	 * restrictions and assumptions in kernel. This basically
43 	 * doesn't add a control file, one cannot attempt to offline
44 	 * BSP.
45 	 *
46 	 * Also certain PCI quirks require not to enable hotplug control
47 	 * for all CPU's.
48 	 */
49 	if (num)
50 		per_cpu(cpu_devices, num).cpu.hotpluggable = 1;
51 
52 	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
53 }
54 EXPORT_SYMBOL(arch_register_cpu);
55 
56 void arch_unregister_cpu(int num)
57 {
58 	unregister_cpu(&per_cpu(cpu_devices, num).cpu);
59 }
60 EXPORT_SYMBOL(arch_unregister_cpu);
61 #else /* CONFIG_HOTPLUG_CPU */
62 
63 static int __init arch_register_cpu(int num)
64 {
65 	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
66 }
67 #endif /* CONFIG_HOTPLUG_CPU */
68 
69 static int __init topology_init(void)
70 {
71 	int i;
72 
73 #ifdef CONFIG_NUMA
74 	for_each_online_node(i)
75 		register_one_node(i);
76 #endif
77 
78 	for_each_present_cpu(i)
79 		arch_register_cpu(i);
80 
81 	return 0;
82 }
83 subsys_initcall(topology_init);
84