arch/s390/kernel/topology.c - maze/linux - Git at Google

 /*
  *    Copyright IBM Corp. 2007, 2011
  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
  */

 #define KMSG_COMPONENT "cpu"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

 #include <linux/workqueue.h>
 #include <linux/bootmem.h>
 #include <linux/cpuset.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/cpu.h>
 #include <linux/smp.h>
 #include <linux/mm.h>
 #include <asm/sysinfo.h>

 #define PTF_HORIZONTAL	(0UL)
 #define PTF_VERTICAL	(1UL)
 #define PTF_CHECK	(2UL)

 struct mask_info {
 	struct mask_info *next;
 	unsigned char id;
 	cpumask_t mask;
 };

 static int topology_enabled = 1;
 static void topology_work_fn(struct work_struct *work);
 static struct sysinfo_15_1_x *tl_info;
 static void set_topology_timer(void);
 static DECLARE_WORK(topology_work, topology_work_fn);
 /* topology_lock protects the core linked list */
 static DEFINE_SPINLOCK(topology_lock);

 static struct mask_info core_info;
 cpumask_t cpu_core_map[NR_CPUS];
 unsigned char cpu_core_id[NR_CPUS];

 static struct mask_info book_info;
 cpumask_t cpu_book_map[NR_CPUS];
 unsigned char cpu_book_id[NR_CPUS];

 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
 {
 	cpumask_t mask;

 	cpumask_clear(&mask);
 	if (!topology_enabled || !MACHINE_HAS_TOPOLOGY) {
 		cpumask_copy(&mask, cpumask_of(cpu));
 		return mask;
 	}
 	while (info) {
 		if (cpumask_test_cpu(cpu, &info->mask)) {
 			mask = info->mask;
 			break;
 		}
 		info = info->next;
 	}
 	if (cpumask_empty(&mask))
 		cpumask_copy(&mask, cpumask_of(cpu));
 	return mask;
 }

 static struct mask_info *add_cpus_to_mask(struct topology_cpu *tl_cpu,
 					  struct mask_info *book,
 					  struct mask_info *core,
 					  int one_core_per_cpu)
 {
 	unsigned int cpu;

 	for_each_set_bit(cpu, &tl_cpu->mask[0], TOPOLOGY_CPU_BITS) {
 		unsigned int rcpu;
 		int lcpu;

 		rcpu = TOPOLOGY_CPU_BITS - 1 - cpu + tl_cpu->origin;
 		lcpu = smp_find_processor_id(rcpu);
 		if (lcpu >= 0) {
 			cpumask_set_cpu(lcpu, &book->mask);
 			cpu_book_id[lcpu] = book->id;
 			cpumask_set_cpu(lcpu, &core->mask);
 			if (one_core_per_cpu) {
 				cpu_core_id[lcpu] = rcpu;
 				core = core->next;
 			} else {
 				cpu_core_id[lcpu] = core->id;
 			}
 			smp_cpu_set_polarization(lcpu, tl_cpu->pp);
 		}
 	}
 	return core;
 }

 static void clear_masks(void)
 {
 	struct mask_info *info;

 	info = &core_info;
 	while (info) {
 		cpumask_clear(&info->mask);
 		info = info->next;
 	}
 	info = &book_info;
 	while (info) {
 		cpumask_clear(&info->mask);
 		info = info->next;
 	}
 }

 static union topology_entry *next_tle(union topology_entry *tle)
 {
 	if (!tle->nl)
 		return (union topology_entry *)((struct topology_cpu *)tle + 1);
 	return (union topology_entry *)((struct topology_container *)tle + 1);
 }

 static void __tl_to_cores_generic(struct sysinfo_15_1_x *info)
 {
 	struct mask_info *core = &core_info;
 	struct mask_info *book = &book_info;
 	union topology_entry *tle, *end;

 	tle = info->tle;
 	end = (union topology_entry *)((unsigned long)info + info->length);
 	while (tle < end) {
 		switch (tle->nl) {
 		case 2:
 			book = book->next;
 			book->id = tle->container.id;
 			break;
 		case 1:
 			core = core->next;
 			core->id = tle->container.id;
 			break;
 		case 0:
 			add_cpus_to_mask(&tle->cpu, book, core, 0);
 			break;
 		default:
 			clear_masks();
 			return;
 		}
 		tle = next_tle(tle);
 	}
 }

 static void __tl_to_cores_z10(struct sysinfo_15_1_x *info)
 {
 	struct mask_info *core = &core_info;
 	struct mask_info *book = &book_info;
 	union topology_entry *tle, *end;

 	tle = info->tle;
 	end = (union topology_entry *)((unsigned long)info + info->length);
 	while (tle < end) {
 		switch (tle->nl) {
 		case 1:
 			book = book->next;
 			book->id = tle->container.id;
 			break;
 		case 0:
 			core = add_cpus_to_mask(&tle->cpu, book, core, 1);
 			break;
 		default:
 			clear_masks();
 			return;
 		}
 		tle = next_tle(tle);
 	}
 }

 static void tl_to_cores(struct sysinfo_15_1_x *info)
 {
 	struct cpuid cpu_id;

 	get_cpu_id(&cpu_id);
 	spin_lock_irq(&topology_lock);
 	clear_masks();
 	switch (cpu_id.machine) {
 	case 0x2097:
 	case 0x2098:
 		__tl_to_cores_z10(info);
 		break;
 	default:
 		__tl_to_cores_generic(info);
 	}
 	spin_unlock_irq(&topology_lock);
 }

 static void topology_update_polarization_simple(void)
 {
 	int cpu;

 	mutex_lock(&smp_cpu_state_mutex);
 	for_each_possible_cpu(cpu)
 		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 	mutex_unlock(&smp_cpu_state_mutex);
 }

 static int ptf(unsigned long fc)
 {
 	int rc;

 	asm volatile(
 		"	.insn	rre,0xb9a20000,%1,%1\n"
 		"	ipm	%0\n"
 		"	srl	%0,28\n"
 		: "=d" (rc)
 		: "d" (fc)  : "cc");
 	return rc;
 }

 int topology_set_cpu_management(int fc)
 {
 	int cpu, rc;

 	if (!MACHINE_HAS_TOPOLOGY)
 		return -EOPNOTSUPP;
 	if (fc)
 		rc = ptf(PTF_VERTICAL);
 	else
 		rc = ptf(PTF_HORIZONTAL);
 	if (rc)
 		return -EBUSY;
 	for_each_possible_cpu(cpu)
 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 	return rc;
 }

 static void update_cpu_core_map(void)
 {
 	unsigned long flags;
 	int cpu;

 	spin_lock_irqsave(&topology_lock, flags);
 	for_each_possible_cpu(cpu) {
 		cpu_core_map[cpu] = cpu_group_map(&core_info, cpu);
 		cpu_book_map[cpu] = cpu_group_map(&book_info, cpu);
 	}
 	spin_unlock_irqrestore(&topology_lock, flags);
 }

 void store_topology(struct sysinfo_15_1_x *info)
 {
 	if (topology_max_mnest >= 3)
 		stsi(info, 15, 1, 3);
 	else
 		stsi(info, 15, 1, 2);
 }

 int arch_update_cpu_topology(void)
 {
 	struct sysinfo_15_1_x *info = tl_info;
 	struct device *dev;
 	int cpu;

 	if (!MACHINE_HAS_TOPOLOGY) {
 		update_cpu_core_map();
 		topology_update_polarization_simple();
 		return 0;
 	}
 	store_topology(info);
 	tl_to_cores(info);
 	update_cpu_core_map();
 	for_each_online_cpu(cpu) {
 		dev = get_cpu_device(cpu);
 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 	}
 	return 1;
 }

 static void topology_work_fn(struct work_struct *work)
 {
 	rebuild_sched_domains();
 }

 void topology_schedule_update(void)
 {
 	schedule_work(&topology_work);
 }

 static void topology_timer_fn(unsigned long ignored)
 {
 	if (ptf(PTF_CHECK))
 		topology_schedule_update();
 	set_topology_timer();
 }

 static struct timer_list topology_timer =
 	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);

 static atomic_t topology_poll = ATOMIC_INIT(0);

 static void set_topology_timer(void)
 {
 	if (atomic_add_unless(&topology_poll, -1, 0))
 		mod_timer(&topology_timer, jiffies + HZ / 10);
 	else
 		mod_timer(&topology_timer, jiffies + HZ * 60);
 }

 void topology_expect_change(void)
 {
 	if (!MACHINE_HAS_TOPOLOGY)
 		return;
 	/* This is racy, but it doesn't matter since it is just a heuristic.
 	 * Worst case is that we poll in a higher frequency for a bit longer.
 	 */
 	if (atomic_read(&topology_poll) > 60)
 		return;
 	atomic_add(60, &topology_poll);
 	set_topology_timer();
 }

 static int __init early_parse_topology(char *p)
 {
 	if (strncmp(p, "off", 3))
 		return 0;
 	topology_enabled = 0;
 	return 0;
 }
 early_param("topology", early_parse_topology);

 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 			       struct mask_info *mask, int offset)
 {
 	int i, nr_masks;

 	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 	for (i = 0; i < info->mnest - offset; i++)
 		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 	nr_masks = max(nr_masks, 1);
 	for (i = 0; i < nr_masks; i++) {
 		mask->next = alloc_bootmem(sizeof(struct mask_info));
 		mask = mask->next;
 	}
 }

 void __init s390_init_cpu_topology(void)
 {
 	struct sysinfo_15_1_x *info;
 	int i;

 	if (!MACHINE_HAS_TOPOLOGY)
 		return;
 	tl_info = alloc_bootmem_pages(PAGE_SIZE);
 	info = tl_info;
 	store_topology(info);
 	pr_info("The CPU configuration topology of the machine is:");
 	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
 		printk(KERN_CONT " %d", info->mag[i]);
 	printk(KERN_CONT " / %d\n", info->mnest);
 	alloc_masks(info, &core_info, 1);
 	alloc_masks(info, &book_info, 2);
 }

 static int cpu_management;

 static ssize_t dispatching_show(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
 {
 	ssize_t count;

 	mutex_lock(&smp_cpu_state_mutex);
 	count = sprintf(buf, "%d\n", cpu_management);
 	mutex_unlock(&smp_cpu_state_mutex);
 	return count;
 }

 static ssize_t dispatching_store(struct device *dev,
 				 struct device_attribute *attr,
 				 const char *buf,
 				 size_t count)
 {
 	int val, rc;
 	char delim;

 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
 		return -EINVAL;
 	if (val != 0 && val != 1)
 		return -EINVAL;
 	rc = 0;
 	get_online_cpus();
 	mutex_lock(&smp_cpu_state_mutex);
 	if (cpu_management == val)
 		goto out;
 	rc = topology_set_cpu_management(val);
 	if (rc)
 		goto out;
 	cpu_management = val;
 	topology_expect_change();
 out:
 	mutex_unlock(&smp_cpu_state_mutex);
 	put_online_cpus();
 	return rc ? rc : count;
 }
 static DEVICE_ATTR(dispatching, 0644, dispatching_show,
 			 dispatching_store);

 static ssize_t cpu_polarization_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
 	int cpu = dev->id;
 	ssize_t count;

 	mutex_lock(&smp_cpu_state_mutex);
 	switch (smp_cpu_get_polarization(cpu)) {
 	case POLARIZATION_HRZ:
 		count = sprintf(buf, "horizontal\n");
 		break;
 	case POLARIZATION_VL:
 		count = sprintf(buf, "vertical:low\n");
 		break;
 	case POLARIZATION_VM:
 		count = sprintf(buf, "vertical:medium\n");
 		break;
 	case POLARIZATION_VH:
 		count = sprintf(buf, "vertical:high\n");
 		break;
 	default:
 		count = sprintf(buf, "unknown\n");
 		break;
 	}
 	mutex_unlock(&smp_cpu_state_mutex);
 	return count;
 }
 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);

 static struct attribute *topology_cpu_attrs[] = {
 	&dev_attr_polarization.attr,
 	NULL,
 };

 static struct attribute_group topology_cpu_attr_group = {
 	.attrs = topology_cpu_attrs,
 };

 int topology_cpu_init(struct cpu *cpu)
 {
 	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 }

 static int __init topology_init(void)
 {
 	if (!MACHINE_HAS_TOPOLOGY) {
 		topology_update_polarization_simple();
 		goto out;
 	}
 	set_topology_timer();
 out:
 	update_cpu_core_map();
 	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 }
 device_initcall(topology_init);
	/*
	* Copyright IBM Corp. 2007, 2011
	* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
	*/

	#define KMSG_COMPONENT "cpu"
	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

	#include <linux/workqueue.h>
	#include <linux/bootmem.h>
	#include <linux/cpuset.h>
	#include <linux/device.h>
	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/cpu.h>
	#include <linux/smp.h>
	#include <linux/mm.h>
	#include <asm/sysinfo.h>

	#define PTF_HORIZONTAL (0UL)
	#define PTF_VERTICAL (1UL)
	#define PTF_CHECK (2UL)

	struct mask_info {
	struct mask_info *next;
	unsigned char id;
	cpumask_t mask;
	};

	static int topology_enabled = 1;
	static void topology_work_fn(struct work_struct *work);
	static struct sysinfo_15_1_x *tl_info;
	static void set_topology_timer(void);
	static DECLARE_WORK(topology_work, topology_work_fn);
	/* topology_lock protects the core linked list */
	static DEFINE_SPINLOCK(topology_lock);

	static struct mask_info core_info;
	cpumask_t cpu_core_map[NR_CPUS];
	unsigned char cpu_core_id[NR_CPUS];

	static struct mask_info book_info;
	cpumask_t cpu_book_map[NR_CPUS];
	unsigned char cpu_book_id[NR_CPUS];

	static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
	{
	cpumask_t mask;

	cpumask_clear(&mask);
	if (!topology_enabled \|\| !MACHINE_HAS_TOPOLOGY) {
	cpumask_copy(&mask, cpumask_of(cpu));
	return mask;
	}
	while (info) {
	if (cpumask_test_cpu(cpu, &info->mask)) {
	mask = info->mask;
	break;
	}
	info = info->next;
	}
	if (cpumask_empty(&mask))
	cpumask_copy(&mask, cpumask_of(cpu));
	return mask;
	}

	static struct mask_info add_cpus_to_mask(struct topology_cpu tl_cpu,
	struct mask_info *book,
	struct mask_info *core,
	int one_core_per_cpu)
	{
	unsigned int cpu;

	for_each_set_bit(cpu, &tl_cpu->mask[0], TOPOLOGY_CPU_BITS) {
	unsigned int rcpu;
	int lcpu;

	rcpu = TOPOLOGY_CPU_BITS - 1 - cpu + tl_cpu->origin;
	lcpu = smp_find_processor_id(rcpu);
	if (lcpu >= 0) {
	cpumask_set_cpu(lcpu, &book->mask);
	cpu_book_id[lcpu] = book->id;
	cpumask_set_cpu(lcpu, &core->mask);
	if (one_core_per_cpu) {
	cpu_core_id[lcpu] = rcpu;
	core = core->next;
	} else {
	cpu_core_id[lcpu] = core->id;
	}
	smp_cpu_set_polarization(lcpu, tl_cpu->pp);
	}
	}
	return core;
	}

	static void clear_masks(void)
	{
	struct mask_info *info;

	info = &core_info;
	while (info) {
	cpumask_clear(&info->mask);
	info = info->next;
	}
	info = &book_info;
	while (info) {
	cpumask_clear(&info->mask);
	info = info->next;
	}
	}

	static union topology_entry next_tle(union topology_entry tle)
	{
	if (!tle->nl)
	return (union topology_entry )((struct topology_cpu )tle + 1);
	return (union topology_entry )((struct topology_container )tle + 1);
	}

	static void __tl_to_cores_generic(struct sysinfo_15_1_x *info)
	{
	struct mask_info *core = &core_info;
	struct mask_info *book = &book_info;
	union topology_entry tle, end;

	tle = info->tle;
	end = (union topology_entry *)((unsigned long)info + info->length);
	while (tle < end) {
	switch (tle->nl) {
	case 2:
	book = book->next;
	book->id = tle->container.id;
	break;
	case 1:
	core = core->next;
	core->id = tle->container.id;
	break;
	case 0:
	add_cpus_to_mask(&tle->cpu, book, core, 0);
	break;
	default:
	clear_masks();
	return;
	}
	tle = next_tle(tle);
	}
	}

	static void __tl_to_cores_z10(struct sysinfo_15_1_x *info)
	{
	struct mask_info *core = &core_info;
	struct mask_info *book = &book_info;
	union topology_entry tle, end;

	tle = info->tle;
	end = (union topology_entry *)((unsigned long)info + info->length);
	while (tle < end) {
	switch (tle->nl) {
	case 1:
	book = book->next;
	book->id = tle->container.id;
	break;
	case 0:
	core = add_cpus_to_mask(&tle->cpu, book, core, 1);
	break;
	default:
	clear_masks();
	return;
	}
	tle = next_tle(tle);
	}
	}

	static void tl_to_cores(struct sysinfo_15_1_x *info)
	{
	struct cpuid cpu_id;

	get_cpu_id(&cpu_id);
	spin_lock_irq(&topology_lock);
	clear_masks();
	switch (cpu_id.machine) {
	case 0x2097:
	case 0x2098:
	__tl_to_cores_z10(info);
	break;
	default:
	__tl_to_cores_generic(info);
	}
	spin_unlock_irq(&topology_lock);
	}

	static void topology_update_polarization_simple(void)
	{
	int cpu;

	mutex_lock(&smp_cpu_state_mutex);
	for_each_possible_cpu(cpu)
	smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
	mutex_unlock(&smp_cpu_state_mutex);
	}

	static int ptf(unsigned long fc)
	{
	int rc;

	asm volatile(
	" .insn rre,0xb9a20000,%1,%1\n"
	" ipm %0\n"
	" srl %0,28\n"
	: "=d" (rc)
	: "d" (fc) : "cc");
	return rc;
	}

	int topology_set_cpu_management(int fc)
	{
	int cpu, rc;

	if (!MACHINE_HAS_TOPOLOGY)
	return -EOPNOTSUPP;
	if (fc)
	rc = ptf(PTF_VERTICAL);
	else
	rc = ptf(PTF_HORIZONTAL);
	if (rc)
	return -EBUSY;
	for_each_possible_cpu(cpu)
	smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
	return rc;
	}

	static void update_cpu_core_map(void)
	{
	unsigned long flags;
	int cpu;

	spin_lock_irqsave(&topology_lock, flags);
	for_each_possible_cpu(cpu) {
	cpu_core_map[cpu] = cpu_group_map(&core_info, cpu);
	cpu_book_map[cpu] = cpu_group_map(&book_info, cpu);
	}
	spin_unlock_irqrestore(&topology_lock, flags);
	}

	void store_topology(struct sysinfo_15_1_x *info)
	{
	if (topology_max_mnest >= 3)
	stsi(info, 15, 1, 3);
	else
	stsi(info, 15, 1, 2);
	}

	int arch_update_cpu_topology(void)
	{
	struct sysinfo_15_1_x *info = tl_info;
	struct device *dev;
	int cpu;

	if (!MACHINE_HAS_TOPOLOGY) {
	update_cpu_core_map();
	topology_update_polarization_simple();
	return 0;
	}
	store_topology(info);
	tl_to_cores(info);
	update_cpu_core_map();
	for_each_online_cpu(cpu) {
	dev = get_cpu_device(cpu);
	kobject_uevent(&dev->kobj, KOBJ_CHANGE);
	}
	return 1;
	}

	static void topology_work_fn(struct work_struct *work)
	{
	rebuild_sched_domains();
	}

	void topology_schedule_update(void)
	{
	schedule_work(&topology_work);
	}

	static void topology_timer_fn(unsigned long ignored)
	{
	if (ptf(PTF_CHECK))
	topology_schedule_update();
	set_topology_timer();
	}

	static struct timer_list topology_timer =
	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);

	static atomic_t topology_poll = ATOMIC_INIT(0);

	static void set_topology_timer(void)
	{
	if (atomic_add_unless(&topology_poll, -1, 0))
	mod_timer(&topology_timer, jiffies + HZ / 10);
	else
	mod_timer(&topology_timer, jiffies + HZ * 60);
	}

	void topology_expect_change(void)
	{
	if (!MACHINE_HAS_TOPOLOGY)
	return;
	/* This is racy, but it doesn't matter since it is just a heuristic.
	* Worst case is that we poll in a higher frequency for a bit longer.
	*/
	if (atomic_read(&topology_poll) > 60)
	return;
	atomic_add(60, &topology_poll);
	set_topology_timer();
	}

	static int __init early_parse_topology(char *p)
	{
	if (strncmp(p, "off", 3))
	return 0;
	topology_enabled = 0;
	return 0;
	}
	early_param("topology", early_parse_topology);

	static void __init alloc_masks(struct sysinfo_15_1_x *info,
	struct mask_info *mask, int offset)
	{
	int i, nr_masks;

	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
	for (i = 0; i < info->mnest - offset; i++)
	nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
	nr_masks = max(nr_masks, 1);
	for (i = 0; i < nr_masks; i++) {
	mask->next = alloc_bootmem(sizeof(struct mask_info));
	mask = mask->next;
	}
	}

	void __init s390_init_cpu_topology(void)
	{
	struct sysinfo_15_1_x *info;
	int i;

	if (!MACHINE_HAS_TOPOLOGY)
	return;
	tl_info = alloc_bootmem_pages(PAGE_SIZE);
	info = tl_info;
	store_topology(info);
	pr_info("The CPU configuration topology of the machine is:");
	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
	printk(KERN_CONT " %d", info->mag[i]);
	printk(KERN_CONT " / %d\n", info->mnest);
	alloc_masks(info, &core_info, 1);
	alloc_masks(info, &book_info, 2);
	}

	static int cpu_management;

	static ssize_t dispatching_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	ssize_t count;

	mutex_lock(&smp_cpu_state_mutex);
	count = sprintf(buf, "%d\n", cpu_management);
	mutex_unlock(&smp_cpu_state_mutex);
	return count;
	}

	static ssize_t dispatching_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t count)
	{
	int val, rc;
	char delim;

	if (sscanf(buf, "%d %c", &val, &delim) != 1)
	return -EINVAL;
	if (val != 0 && val != 1)
	return -EINVAL;
	rc = 0;
	get_online_cpus();
	mutex_lock(&smp_cpu_state_mutex);
	if (cpu_management == val)
	goto out;
	rc = topology_set_cpu_management(val);
	if (rc)
	goto out;
	cpu_management = val;
	topology_expect_change();
	out:
	mutex_unlock(&smp_cpu_state_mutex);
	put_online_cpus();
	return rc ? rc : count;
	}
	static DEVICE_ATTR(dispatching, 0644, dispatching_show,
	dispatching_store);

	static ssize_t cpu_polarization_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	int cpu = dev->id;
	ssize_t count;

	mutex_lock(&smp_cpu_state_mutex);
	switch (smp_cpu_get_polarization(cpu)) {
	case POLARIZATION_HRZ:
	count = sprintf(buf, "horizontal\n");
	break;
	case POLARIZATION_VL:
	count = sprintf(buf, "vertical:low\n");
	break;
	case POLARIZATION_VM:
	count = sprintf(buf, "vertical:medium\n");
	break;
	case POLARIZATION_VH:
	count = sprintf(buf, "vertical:high\n");
	break;
	default:
	count = sprintf(buf, "unknown\n");
	break;
	}
	mutex_unlock(&smp_cpu_state_mutex);
	return count;
	}
	static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);

	static struct attribute *topology_cpu_attrs[] = {
	&dev_attr_polarization.attr,
	NULL,
	};

	static struct attribute_group topology_cpu_attr_group = {
	.attrs = topology_cpu_attrs,
	};

	int topology_cpu_init(struct cpu *cpu)
	{
	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
	}

	static int __init topology_init(void)
	{
	if (!MACHINE_HAS_TOPOLOGY) {
	topology_update_polarization_simple();
	goto out;
	}
	set_topology_timer();
	out:
	update_cpu_core_map();
	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
	}
	device_initcall(topology_init);