[deliverable/linux.git] / arch / x86 / kernel / topology.c

/*
 * Populate sysfs with topology information
 *
 * Written by: Matthew Dobson, IBM Corporation
 * Original Code: Paul Dorwin, IBM Corporation, Patrick Mochel, OSDL
 *
 * Copyright (C) 2002, IBM Corp.
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to <colpatch@us.ibm.com>
 */
#include <linux/nodemask.h>
#include <linux/export.h>
#include <linux/mmzone.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/irq.h>
#include <asm/cpu.h>

static DEFINE_PER_CPU(struct x86_cpu, cpu_devices);

#ifdef CONFIG_HOTPLUG_CPU

#ifdef CONFIG_BOOTPARAM_HOTPLUG_CPU0
static int cpu0_hotpluggable = 1;
#else
static int cpu0_hotpluggable;
static int __init enable_cpu0_hotplug(char *str)
{
	cpu0_hotpluggable = 1;
	return 1;
}

__setup("cpu0_hotplug", enable_cpu0_hotplug);
#endif

#ifdef CONFIG_DEBUG_HOTPLUG_CPU0
/*
 * This function offlines a CPU as early as possible and allows userspace to
 * boot up without the CPU. The CPU can be onlined back by user after boot.
 *
 * This is only called for debugging CPU offline/online feature.
 */
int _debug_hotplug_cpu(int cpu, int action)
{
	struct device *dev = get_cpu_device(cpu);
	int ret;

	if (!cpu_is_hotpluggable(cpu))
		return -EINVAL;

	lock_device_hotplug();

	switch (action) {
	case 0:
		ret = cpu_down(cpu);
		if (!ret) {
			pr_info("CPU %u is now offline\n", cpu);
			dev->offline = true;
			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
		} else
			pr_debug("Can't offline CPU%d.\n", cpu);
		break;
	case 1:
		ret = cpu_up(cpu);
		if (!ret) {
			dev->offline = false;
			kobject_uevent(&dev->kobj, KOBJ_ONLINE);
		} else {
			pr_debug("Can't online CPU%d.\n", cpu);
		}
		break;
	default:
		ret = -EINVAL;
	}

	unlock_device_hotplug();

	return ret;
}

static int __init debug_hotplug_cpu(void)
{
	_debug_hotplug_cpu(0, 0);
	return 0;
}

late_initcall_sync(debug_hotplug_cpu);
#endif /* CONFIG_DEBUG_HOTPLUG_CPU0 */

int arch_register_cpu(int num)
{
	struct cpuinfo_x86 *c = &cpu_data(num);

	/*
	 * Currently CPU0 is only hotpluggable on Intel platforms. Other
	 * vendors can add hotplug support later.
	 */
	if (c->x86_vendor != X86_VENDOR_INTEL)
		cpu0_hotpluggable = 0;

	/*
	 * Two known BSP/CPU0 dependencies: Resume from suspend/hibernate
	 * depends on BSP. PIC interrupts depend on BSP.
	 *
	 * If the BSP depencies are under control, one can tell kernel to
	 * enable BSP hotplug. This basically adds a control file and
	 * one can attempt to offline BSP.
	 */
	if (num == 0 && cpu0_hotpluggable) {
		unsigned int irq;
		/*
		 * We won't take down the boot processor on i386 if some
		 * interrupts only are able to be serviced by the BSP in PIC.
		 */
		for_each_active_irq(irq) {
			if (!IO_APIC_IRQ(irq) && irq_has_action(irq)) {
				cpu0_hotpluggable = 0;
				break;
			}
		}
	}
	if (num || cpu0_hotpluggable)
		per_cpu(cpu_devices, num).cpu.hotpluggable = 1;

	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
}
EXPORT_SYMBOL(arch_register_cpu);

void arch_unregister_cpu(int num)
{
	unregister_cpu(&per_cpu(cpu_devices, num).cpu);
}
EXPORT_SYMBOL(arch_unregister_cpu);
#else /* CONFIG_HOTPLUG_CPU */

static int __init arch_register_cpu(int num)
{
	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
}
#endif /* CONFIG_HOTPLUG_CPU */

static int __init topology_init(void)
{
	int i;

#ifdef CONFIG_NUMA
	for_each_online_node(i)
		register_one_node(i);
#endif

	for_each_present_cpu(i)
		arch_register_cpu(i);

	return 0;
}
subsys_initcall(topology_init);
Commit	Line	Data
1da177e4	1	/*
835c34a1	2	* Populate sysfs with topology information
1da177e4 LT	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	*
9c869eda	9	* All rights reserved.
1da177e4 LT	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	*/
1da177e4	28	#include <linux/nodemask.h>
69c60c88	29	#include <linux/export.h>
aada06c9	30	#include <linux/mmzone.h>
271eb5c5 JSR	31	#include <linux/init.h>
271eb5c5 JSR	32	#include <linux/smp.h>
4d25031a	33	#include <linux/irq.h>
1da177e4 LT	34	#include <asm/cpu.h>
1da177e4 LT	35
30964d54	36	static DEFINE_PER_CPU(struct x86_cpu, cpu_devices);
1da177e4	37
3eaf5efa	38	#ifdef CONFIG_HOTPLUG_CPU
4d25031a FY	39
	40	#ifdef CONFIG_BOOTPARAM_HOTPLUG_CPU0
	41	static int cpu0_hotpluggable = 1;
	42	#else
	43	static int cpu0_hotpluggable;
	44	static 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
a71c8bc5 FY	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	*/
4daa832d	60	int _debug_hotplug_cpu(int cpu, int action)
a71c8bc5 FY	61	{
	62	struct device *dev = get_cpu_device(cpu);
	63	int ret;
	64
	65	if (!cpu_is_hotpluggable(cpu))
	66	return -EINVAL;
	67
574b851e	68	lock_device_hotplug();
a71c8bc5 FY	69
	70	switch (action) {
	71	case 0:
	72	ret = cpu_down(cpu);
	73	if (!ret) {
	74	pr_info("CPU %u is now offline\n", cpu);
f6913f99	75	dev->offline = true;
a71c8bc5 FY	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);
f6913f99 TK	82	if (!ret) {
f6913f99 TK	83	dev->offline = false;
a71c8bc5	84	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
f6913f99	85	} else {
a71c8bc5	86	pr_debug("Can't online CPU%d.\n", cpu);
f6913f99	87	}
a71c8bc5 FY	88	break;
	89	default:
	90	ret = -EINVAL;
	91	}
	92
574b851e	93	unlock_device_hotplug();
a71c8bc5 FY	94
	95	return ret;
	96	}
	97
	98	static int __init debug_hotplug_cpu(void)
	99	{
	100	_debug_hotplug_cpu(0, 0);
	101	return 0;
	102	}
	103
	104	late_initcall_sync(debug_hotplug_cpu);
	105	#endif /* CONFIG_DEBUG_HOTPLUG_CPU0 */
	106
4daa832d	107	int arch_register_cpu(int num)
76b67ed9	108	{
4d25031a FY	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	*/
	115	if (c->x86_vendor != X86_VENDOR_INTEL)
	116	cpu0_hotpluggable = 0;
	117
bdaff4a3	118	/*
4d25031a FY	119	* Two known BSP/CPU0 dependencies: Resume from suspend/hibernate
4d25031a FY	120	* depends on BSP. PIC interrupts depend on BSP.
fd6d7d26	121	*
4d25031a FY	122	* If the BSP depencies are under control, one can tell kernel to
	123	* enable BSP hotplug. This basically adds a control file and
	124	* one can attempt to offline BSP.
bdaff4a3	125	*/
4d25031a FY	126	if (num == 0 && cpu0_hotpluggable) {
	127	unsigned int irq;
	128	/*
	129	* We won't take down the boot processor on i386 if some
	130	* interrupts only are able to be serviced by the BSP in PIC.
	131	*/
	132	for_each_active_irq(irq) {
	133	if (!IO_APIC_IRQ(irq) && irq_has_action(irq)) {
	134	cpu0_hotpluggable = 0;
	135	break;
	136	}
	137	}
	138	}
	139	if (num \|\| cpu0_hotpluggable)
30964d54	140	per_cpu(cpu_devices, num).cpu.hotpluggable = 1;
271eb5c5	141
30964d54	142	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
1da177e4	143	}
3eaf5efa	144	EXPORT_SYMBOL(arch_register_cpu);
1da177e4	145
da54becc AM	146	void arch_unregister_cpu(int num)
da54becc AM	147	{
9583d050	148	unregister_cpu(&per_cpu(cpu_devices, num).cpu);
1da177e4	149	}
1da177e4	150	EXPORT_SYMBOL(arch_unregister_cpu);
271eb5c5 JSR	151	#else /* CONFIG_HOTPLUG_CPU */
271eb5c5 JSR	152
d9874026	153	static int __init arch_register_cpu(int num)
3eaf5efa SR	154	{
	155	return register_cpu(&per_cpu(cpu_devices, num).cpu, num);
	156	}
271eb5c5	157	#endif /* CONFIG_HOTPLUG_CPU */
1da177e4	158
1da177e4 LT	159	static int __init topology_init(void)
	160	{
	161	int i;
	162
aada06c9	163	#ifdef CONFIG_NUMA
76e4f660	164	for_each_online_node(i)
0fc44159	165	register_one_node(i);
271eb5c5	166	#endif
76e4f660	167
a888cebe	168	for_each_present_cpu(i)
76e4f660	169	arch_register_cpu(i);
271eb5c5	170
1da177e4 LT	171	return 0;
1da177e4 LT	172	}
1da177e4	173	subsys_initcall(topology_init);