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 <linux/irq.h>
 34#include <asm/cpu.h>
 35
 36static DEFINE_PER_CPU(struct x86_cpu, cpu_devices);
 37
 38#ifdef CONFIG_HOTPLUG_CPU
 39
 40#ifdef CONFIG_BOOTPARAM_HOTPLUG_CPU0
 41static int cpu0_hotpluggable = 1;
 42#else
 43static int cpu0_hotpluggable;
 44static int __init enable_cpu0_hotplug(char *str)
 45{
 46	cpu0_hotpluggable = 1;
 47	return 1;
 48}
 49
 50__setup("cpu0_hotplug", enable_cpu0_hotplug);
 51#endif
 52
 53#ifdef CONFIG_DEBUG_HOTPLUG_CPU0
 54/*
 55 * This function offlines a CPU as early as possible and allows userspace to
 56 * boot up without the CPU. The CPU can be onlined back by user after boot.
 57 *
 58 * This is only called for debugging CPU offline/online feature.
 59 */
 60int _debug_hotplug_cpu(int cpu, int action)
 61{
 62	struct device *dev = get_cpu_device(cpu);
 63	int ret;
 64
 65	if (!cpu_is_hotpluggable(cpu))
 66		return -EINVAL;
 67
 68	lock_device_hotplug();
 69
 70	switch (action) {
 71	case 0:
 72		ret = cpu_down(cpu);
 73		if (!ret) {
 74			pr_info("DEBUG_HOTPLUG_CPU0: CPU %u is now offline\n", cpu);
 75			dev->offline = true;
 76			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
 77		} else
 78			pr_debug("Can't offline CPU%d.\n", cpu);
 79		break;
 80	case 1:
 81		ret = cpu_up(cpu);
 82		if (!ret) {
 83			dev->offline = false;
 84			kobject_uevent(&dev->kobj, KOBJ_ONLINE);
 85		} else {
 86			pr_debug("Can't online CPU%d.\n", cpu);
 87		}
 88		break;
 89	default:
 90		ret = -EINVAL;
 91	}
 92
 93	unlock_device_hotplug();
 94
 95	return ret;
 96}
 97
 98static int __init debug_hotplug_cpu(void)
 99{
100	_debug_hotplug_cpu(0, 0);
101	return 0;
102}
103
104late_initcall_sync(debug_hotplug_cpu);
105#endif /* CONFIG_DEBUG_HOTPLUG_CPU0 */
106
107int arch_register_cpu(int num)
108{
109	struct cpuinfo_x86 *c = &cpu_data(num);
110
111	/*
112	 * Currently CPU0 is only hotpluggable on Intel platforms. Other
113	 * vendors can add hotplug support later.
114	 * Xen PV guests don't support CPU0 hotplug at all.
115	 */
116	if (c->x86_vendor != X86_VENDOR_INTEL ||
117	    boot_cpu_has(X86_FEATURE_XENPV))
118		cpu0_hotpluggable = 0;
119
120	/*
121	 * Two known BSP/CPU0 dependencies: Resume from suspend/hibernate
122	 * depends on BSP. PIC interrupts depend on BSP.
 
 
123	 *
124	 * If the BSP depencies are under control, one can tell kernel to
125	 * enable BSP hotplug. This basically adds a control file and
126	 * one can attempt to offline BSP.
127	 */
128	if (num == 0 && cpu0_hotpluggable) {
129		unsigned int irq;
130		/*
131		 * We won't take down the boot processor on i386 if some
132		 * interrupts only are able to be serviced by the BSP in PIC.
133		 */
134		for_each_active_irq(irq) {
135			if (!IO_APIC_IRQ(irq) && irq_has_action(irq)) {
136				cpu0_hotpluggable = 0;
137				break;
138			}
139		}
140	}
141	if (num || cpu0_hotpluggable)
142		per_cpu(cpu_devices, num).cpu.hotpluggable = 1;
143
144	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
145}
146EXPORT_SYMBOL(arch_register_cpu);
147
148void arch_unregister_cpu(int num)
149{
150	unregister_cpu(&per_cpu(cpu_devices, num).cpu);
151}
152EXPORT_SYMBOL(arch_unregister_cpu);
153#else /* CONFIG_HOTPLUG_CPU */
154
155static int __init arch_register_cpu(int num)
156{
157	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
158}
159#endif /* CONFIG_HOTPLUG_CPU */
160
161static int __init topology_init(void)
162{
163	int i;
164
165#ifdef CONFIG_NUMA
166	for_each_online_node(i)
167		register_one_node(i);
168#endif
169
170	for_each_present_cpu(i)
171		arch_register_cpu(i);
172
173	return 0;
174}
175subsys_initcall(topology_init);

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