[linux.git] / kernel / cpu.c

/* CPU control.
 * (C) 2001, 2002, 2003, 2004 Rusty Russell
 *
 * This code is licenced under the GPL.
 */
#include <linux/proc_fs.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/unistd.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/stop_machine.h>
#include <linux/mutex.h>

/* This protects CPUs going up and down... */
static DEFINE_MUTEX(cpu_add_remove_lock);
static DEFINE_MUTEX(cpu_bitmask_lock);

static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);

/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
 * Should always be manipulated under cpu_add_remove_lock
 */
static int cpu_hotplug_disabled;

#ifdef CONFIG_HOTPLUG_CPU

/* Crappy recursive lock-takers in cpufreq! Complain loudly about idiots */
static struct task_struct *recursive;
static int recursive_depth;

void lock_cpu_hotplug(void)
{
	struct task_struct *tsk = current;

	if (tsk == recursive) {
		static int warnings = 10;
		if (warnings) {
			printk(KERN_ERR "Lukewarm IQ detected in hotplug locking\n");
			WARN_ON(1);
			warnings--;
		}
		recursive_depth++;
		return;
	}
	mutex_lock(&cpu_bitmask_lock);
	recursive = tsk;
}
EXPORT_SYMBOL_GPL(lock_cpu_hotplug);

void unlock_cpu_hotplug(void)
{
	WARN_ON(recursive != current);
	if (recursive_depth) {
		recursive_depth--;
		return;
	}
	recursive = NULL;
	mutex_unlock(&cpu_bitmask_lock);
}
EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);

#endif	/* CONFIG_HOTPLUG_CPU */

/* Need to know about CPUs going up/down? */
int __cpuinit register_cpu_notifier(struct notifier_block *nb)
{
	int ret;
	mutex_lock(&cpu_add_remove_lock);
	ret = raw_notifier_chain_register(&cpu_chain, nb);
	mutex_unlock(&cpu_add_remove_lock);
	return ret;
}

#ifdef CONFIG_HOTPLUG_CPU

EXPORT_SYMBOL(register_cpu_notifier);

void unregister_cpu_notifier(struct notifier_block *nb)
{
	mutex_lock(&cpu_add_remove_lock);
	raw_notifier_chain_unregister(&cpu_chain, nb);
	mutex_unlock(&cpu_add_remove_lock);
}
EXPORT_SYMBOL(unregister_cpu_notifier);

static inline void check_for_tasks(int cpu)
{
	struct task_struct *p;

	write_lock_irq(&tasklist_lock);
	for_each_process(p) {
		if (task_cpu(p) == cpu &&
		    (!cputime_eq(p->utime, cputime_zero) ||
		     !cputime_eq(p->stime, cputime_zero)))
			printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
				(state = %ld, flags = %x) \n",
				 p->comm, p->pid, cpu, p->state, p->flags);
	}
	write_unlock_irq(&tasklist_lock);
}

/* Take this CPU down. */
static int take_cpu_down(void *unused)
{
	int err;

	/* Ensure this CPU doesn't handle any more interrupts. */
	err = __cpu_disable();
	if (err < 0)
		return err;

	/* Force idle task to run as soon as we yield: it should
	   immediately notice cpu is offline and die quickly. */
	sched_idle_next();
	return 0;
}

/* Requires cpu_add_remove_lock to be held */
static int _cpu_down(unsigned int cpu)
{
	int err, nr_calls = 0;
	struct task_struct *p;
	cpumask_t old_allowed, tmp;
	void *hcpu = (void *)(long)cpu;

	if (num_online_cpus() == 1)
		return -EBUSY;

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

	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
	err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
					hcpu, -1, &nr_calls);
	if (err == NOTIFY_BAD) {
		__raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, hcpu,
					  nr_calls, NULL);
		printk("%s: attempt to take down CPU %u failed\n",
				__FUNCTION__, cpu);
		err = -EINVAL;
		goto out_release;
	}

	/* Ensure that we are not runnable on dying cpu */
	old_allowed = current->cpus_allowed;
	tmp = CPU_MASK_ALL;
	cpu_clear(cpu, tmp);
	set_cpus_allowed(current, tmp);

	mutex_lock(&cpu_bitmask_lock);
	p = __stop_machine_run(take_cpu_down, NULL, cpu);
	mutex_unlock(&cpu_bitmask_lock);

	if (IS_ERR(p) || cpu_online(cpu)) {
		/* CPU didn't die: tell everyone.  Can't complain. */
		if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
					    hcpu) == NOTIFY_BAD)
			BUG();

		if (IS_ERR(p)) {
			err = PTR_ERR(p);
			goto out_allowed;
		}
		goto out_thread;
	}

	/* Wait for it to sleep (leaving idle task). */
	while (!idle_cpu(cpu))
		yield();

	/* This actually kills the CPU. */
	__cpu_die(cpu);

	/* Move it here so it can run. */
	kthread_bind(p, get_cpu());
	put_cpu();

	/* CPU is completely dead: tell everyone.  Too late to complain. */
	if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD, hcpu) == NOTIFY_BAD)
		BUG();

	check_for_tasks(cpu);

out_thread:
	err = kthread_stop(p);
out_allowed:
	set_cpus_allowed(current, old_allowed);
out_release:
	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE,
						(void *)(long)cpu);
	return err;
}

int cpu_down(unsigned int cpu)
{
	int err = 0;

	mutex_lock(&cpu_add_remove_lock);
	if (cpu_hotplug_disabled)
		err = -EBUSY;
	else
		err = _cpu_down(cpu);

	mutex_unlock(&cpu_add_remove_lock);
	return err;
}
#endif /*CONFIG_HOTPLUG_CPU*/

/* Requires cpu_add_remove_lock to be held */
static int __cpuinit _cpu_up(unsigned int cpu)
{
	int ret, nr_calls = 0;
	void *hcpu = (void *)(long)cpu;

	if (cpu_online(cpu) || !cpu_present(cpu))
		return -EINVAL;

	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
	ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu,
							-1, &nr_calls);
	if (ret == NOTIFY_BAD) {
		printk("%s: attempt to bring up CPU %u failed\n",
				__FUNCTION__, cpu);
		ret = -EINVAL;
		goto out_notify;
	}

	/* Arch-specific enabling code. */
	mutex_lock(&cpu_bitmask_lock);
	ret = __cpu_up(cpu);
	mutex_unlock(&cpu_bitmask_lock);
	if (ret != 0)
		goto out_notify;
	BUG_ON(!cpu_online(cpu));

	/* Now call notifier in preparation. */
	raw_notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);

out_notify:
	if (ret != 0)
		__raw_notifier_call_chain(&cpu_chain,
				CPU_UP_CANCELED, hcpu, nr_calls, NULL);
	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE, hcpu);

	return ret;
}

int __cpuinit cpu_up(unsigned int cpu)
{
	int err = 0;

	mutex_lock(&cpu_add_remove_lock);
	if (cpu_hotplug_disabled)
		err = -EBUSY;
	else
		err = _cpu_up(cpu);

	mutex_unlock(&cpu_add_remove_lock);
	return err;
}

#ifdef CONFIG_SUSPEND_SMP
/* Needed to prevent the microcode driver from requesting firmware in its CPU
 * hotplug notifier during the suspend/resume.
 */
int suspend_cpu_hotplug;
EXPORT_SYMBOL(suspend_cpu_hotplug);

static cpumask_t frozen_cpus;

int disable_nonboot_cpus(void)
{
	int cpu, first_cpu, error = 0;

	mutex_lock(&cpu_add_remove_lock);
	suspend_cpu_hotplug = 1;
	first_cpu = first_cpu(cpu_online_map);
	/* We take down all of the non-boot CPUs in one shot to avoid races
	 * with the userspace trying to use the CPU hotplug at the same time
	 */
	cpus_clear(frozen_cpus);
	printk("Disabling non-boot CPUs ...\n");
	for_each_online_cpu(cpu) {
		if (cpu == first_cpu)
			continue;
		error = _cpu_down(cpu);
		if (!error) {
			cpu_set(cpu, frozen_cpus);
			printk("CPU%d is down\n", cpu);
		} else {
			printk(KERN_ERR "Error taking CPU%d down: %d\n",
				cpu, error);
			break;
		}
	}
	if (!error) {
		BUG_ON(num_online_cpus() > 1);
		/* Make sure the CPUs won't be enabled by someone else */
		cpu_hotplug_disabled = 1;
	} else {
		printk(KERN_ERR "Non-boot CPUs are not disabled\n");
	}
	suspend_cpu_hotplug = 0;
	mutex_unlock(&cpu_add_remove_lock);
	return error;
}

void enable_nonboot_cpus(void)
{
	int cpu, error;

	/* Allow everyone to use the CPU hotplug again */
	mutex_lock(&cpu_add_remove_lock);
	cpu_hotplug_disabled = 0;
	if (cpus_empty(frozen_cpus))
		goto out;

	suspend_cpu_hotplug = 1;
	printk("Enabling non-boot CPUs ...\n");
	for_each_cpu_mask(cpu, frozen_cpus) {
		error = _cpu_up(cpu);
		if (!error) {
			printk("CPU%d is up\n", cpu);
			continue;
		}
		printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error);
	}
	cpus_clear(frozen_cpus);
	suspend_cpu_hotplug = 0;
out:
	mutex_unlock(&cpu_add_remove_lock);
}
#endif
Commit	Line	Data
1da177e4 LT	1	/* CPU control.
	2	* (C) 2001, 2002, 2003, 2004 Rusty Russell
	3	*
	4	* This code is licenced under the GPL.
	5	*/
	6	#include <linux/proc_fs.h>
	7	#include <linux/smp.h>
	8	#include <linux/init.h>
	9	#include <linux/notifier.h>
	10	#include <linux/sched.h>
	11	#include <linux/unistd.h>
	12	#include <linux/cpu.h>
	13	#include <linux/module.h>
	14	#include <linux/kthread.h>
	15	#include <linux/stop_machine.h>
81615b62	16	#include <linux/mutex.h>
1da177e4 LT	17
1da177e4 LT	18	/* This protects CPUs going up and down... */
aa953877 LT	19	static DEFINE_MUTEX(cpu_add_remove_lock);
aa953877 LT	20	static DEFINE_MUTEX(cpu_bitmask_lock);
1da177e4	21
bd5349cf	22	static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
1da177e4	23
e3920fb4 RW	24	/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
	25	* Should always be manipulated under cpu_add_remove_lock
	26	*/
	27	static int cpu_hotplug_disabled;
	28
a9d9baa1	29	#ifdef CONFIG_HOTPLUG_CPU
90d45d17	30
aa953877 LT	31	/* Crappy recursive lock-takers in cpufreq! Complain loudly about idiots */
	32	static struct task_struct *recursive;
	33	static int recursive_depth;
90d45d17	34
a9d9baa1 AR	35	void lock_cpu_hotplug(void)
a9d9baa1 AR	36	{
aa953877 LT	37	struct task_struct *tsk = current;
	38
	39	if (tsk == recursive) {
	40	static int warnings = 10;
	41	if (warnings) {
	42	printk(KERN_ERR "Lukewarm IQ detected in hotplug locking\n");
	43	WARN_ON(1);
	44	warnings--;
	45	}
	46	recursive_depth++;
	47	return;
	48	}
	49	mutex_lock(&cpu_bitmask_lock);
	50	recursive = tsk;
a9d9baa1 AR	51	}
a9d9baa1 AR	52	EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
90d45d17	53
a9d9baa1 AR	54	void unlock_cpu_hotplug(void)
a9d9baa1 AR	55	{
aa953877 LT	56	WARN_ON(recursive != current);
	57	if (recursive_depth) {
	58	recursive_depth--;
	59	return;
a9d9baa1	60	}
aa953877	61	recursive = NULL;
4b96b1a1	62	mutex_unlock(&cpu_bitmask_lock);
a9d9baa1 AR	63	}
	64	EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
	65
a9d9baa1	66	#endif /* CONFIG_HOTPLUG_CPU */
90d45d17	67
1da177e4	68	/* Need to know about CPUs going up/down? */
65edc68c	69	int __cpuinit register_cpu_notifier(struct notifier_block *nb)
1da177e4	70	{
bd5349cf NB	71	int ret;
	72	mutex_lock(&cpu_add_remove_lock);
	73	ret = raw_notifier_chain_register(&cpu_chain, nb);
	74	mutex_unlock(&cpu_add_remove_lock);
	75	return ret;
1da177e4	76	}
65edc68c CS	77
	78	#ifdef CONFIG_HOTPLUG_CPU
	79
1da177e4 LT	80	EXPORT_SYMBOL(register_cpu_notifier);
	81
	82	void unregister_cpu_notifier(struct notifier_block *nb)
	83	{
bd5349cf NB	84	mutex_lock(&cpu_add_remove_lock);
	85	raw_notifier_chain_unregister(&cpu_chain, nb);
	86	mutex_unlock(&cpu_add_remove_lock);
1da177e4 LT	87	}
	88	EXPORT_SYMBOL(unregister_cpu_notifier);
	89
1da177e4 LT	90	static inline void check_for_tasks(int cpu)
	91	{
	92	struct task_struct *p;
	93
	94	write_lock_irq(&tasklist_lock);
	95	for_each_process(p) {
	96	if (task_cpu(p) == cpu &&
	97	(!cputime_eq(p->utime, cputime_zero) \|\|
	98	!cputime_eq(p->stime, cputime_zero)))
	99	printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
e7407dcc	100	(state = %ld, flags = %x) \n",
1da177e4 LT	101	p->comm, p->pid, cpu, p->state, p->flags);
	102	}
	103	write_unlock_irq(&tasklist_lock);
	104	}
	105
	106	/* Take this CPU down. */
	107	static int take_cpu_down(void *unused)
	108	{
	109	int err;
	110
1da177e4 LT	111	/* Ensure this CPU doesn't handle any more interrupts. */
	112	err = __cpu_disable();
	113	if (err < 0)
f3705136	114	return err;
1da177e4	115
f3705136 ZM	116	/* Force idle task to run as soon as we yield: it should
	117	immediately notice cpu is offline and die quickly. */
	118	sched_idle_next();
	119	return 0;
1da177e4 LT	120	}
1da177e4 LT	121
e3920fb4 RW	122	/* Requires cpu_add_remove_lock to be held */
e3920fb4 RW	123	static int _cpu_down(unsigned int cpu)
1da177e4	124	{
e7407dcc	125	int err, nr_calls = 0;
1da177e4 LT	126	struct task_struct *p;
1da177e4 LT	127	cpumask_t old_allowed, tmp;
e7407dcc	128	void hcpu = (void )(long)cpu;
1da177e4	129
e3920fb4 RW	130	if (num_online_cpus() == 1)
e3920fb4 RW	131	return -EBUSY;
1da177e4	132
e3920fb4 RW	133	if (!cpu_online(cpu))
e3920fb4 RW	134	return -EINVAL;
1da177e4	135
e7407dcc HC	136	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
	137	err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
	138	hcpu, -1, &nr_calls);
1da177e4	139	if (err == NOTIFY_BAD) {
e7407dcc HC	140	__raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, hcpu,
e7407dcc HC	141	nr_calls, NULL);
1da177e4 LT	142	printk("%s: attempt to take down CPU %u failed\n",
1da177e4 LT	143	__FUNCTION__, cpu);
baaca49f GS	144	err = -EINVAL;
baaca49f GS	145	goto out_release;
1da177e4 LT	146	}
	147
	148	/* Ensure that we are not runnable on dying cpu */
	149	old_allowed = current->cpus_allowed;
	150	tmp = CPU_MASK_ALL;
	151	cpu_clear(cpu, tmp);
	152	set_cpus_allowed(current, tmp);
	153
aa953877	154	mutex_lock(&cpu_bitmask_lock);
1da177e4	155	p = __stop_machine_run(take_cpu_down, NULL, cpu);
aa953877 LT	156	mutex_unlock(&cpu_bitmask_lock);
aa953877 LT	157
8fa1d7d3	158	if (IS_ERR(p) \|\| cpu_online(cpu)) {
1da177e4	159	/* CPU didn't die: tell everyone. Can't complain. */
bd5349cf	160	if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
e7407dcc	161	hcpu) == NOTIFY_BAD)
1da177e4 LT	162	BUG();
1da177e4 LT	163
8fa1d7d3 ST	164	if (IS_ERR(p)) {
	165	err = PTR_ERR(p);
	166	goto out_allowed;
	167	}
1da177e4	168	goto out_thread;
8fa1d7d3	169	}
1da177e4 LT	170
	171	/* Wait for it to sleep (leaving idle task). */
	172	while (!idle_cpu(cpu))
	173	yield();
	174
	175	/* This actually kills the CPU. */
	176	__cpu_die(cpu);
	177
	178	/* Move it here so it can run. */
	179	kthread_bind(p, get_cpu());
	180	put_cpu();
	181
	182	/* CPU is completely dead: tell everyone. Too late to complain. */
e7407dcc	183	if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD, hcpu) == NOTIFY_BAD)
1da177e4 LT	184	BUG();
	185
	186	check_for_tasks(cpu);
	187
	188	out_thread:
	189	err = kthread_stop(p);
	190	out_allowed:
	191	set_cpus_allowed(current, old_allowed);
baaca49f GS	192	out_release:
	193	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE,
	194	(void *)(long)cpu);
e3920fb4 RW	195	return err;
	196	}
	197
	198	int cpu_down(unsigned int cpu)
	199	{
	200	int err = 0;
	201
	202	mutex_lock(&cpu_add_remove_lock);
	203	if (cpu_hotplug_disabled)
	204	err = -EBUSY;
	205	else
	206	err = _cpu_down(cpu);
	207
aa953877	208	mutex_unlock(&cpu_add_remove_lock);
1da177e4 LT	209	return err;
	210	}
	211	#endif /CONFIG_HOTPLUG_CPU/
	212
e3920fb4	213	/* Requires cpu_add_remove_lock to be held */
b282b6f8	214	static int __cpuinit _cpu_up(unsigned int cpu)
1da177e4	215	{
baaca49f	216	int ret, nr_calls = 0;
1da177e4 LT	217	void hcpu = (void )(long)cpu;
1da177e4 LT	218
e3920fb4 RW	219	if (cpu_online(cpu) \|\| !cpu_present(cpu))
e3920fb4 RW	220	return -EINVAL;
90d45d17	221
baaca49f GS	222	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
	223	ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu,
	224	-1, &nr_calls);
1da177e4 LT	225	if (ret == NOTIFY_BAD) {
	226	printk("%s: attempt to bring up CPU %u failed\n",
	227	__FUNCTION__, cpu);
	228	ret = -EINVAL;
	229	goto out_notify;
	230	}
	231
	232	/* Arch-specific enabling code. */
aa953877	233	mutex_lock(&cpu_bitmask_lock);
1da177e4	234	ret = __cpu_up(cpu);
aa953877	235	mutex_unlock(&cpu_bitmask_lock);
1da177e4 LT	236	if (ret != 0)
1da177e4 LT	237	goto out_notify;
6978c705	238	BUG_ON(!cpu_online(cpu));
1da177e4 LT	239
1da177e4 LT	240	/* Now call notifier in preparation. */
bd5349cf	241	raw_notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);
1da177e4 LT	242
	243	out_notify:
	244	if (ret != 0)
baaca49f GS	245	__raw_notifier_call_chain(&cpu_chain,
	246	CPU_UP_CANCELED, hcpu, nr_calls, NULL);
	247	raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE, hcpu);
e3920fb4 RW	248
	249	return ret;
	250	}
	251
b282b6f8	252	int __cpuinit cpu_up(unsigned int cpu)
e3920fb4 RW	253	{
	254	int err = 0;
	255
	256	mutex_lock(&cpu_add_remove_lock);
	257	if (cpu_hotplug_disabled)
	258	err = -EBUSY;
	259	else
	260	err = _cpu_up(cpu);
	261
	262	mutex_unlock(&cpu_add_remove_lock);
	263	return err;
	264	}
	265
	266	#ifdef CONFIG_SUSPEND_SMP
1d64b9cb RW	267	/* Needed to prevent the microcode driver from requesting firmware in its CPU
	268	* hotplug notifier during the suspend/resume.
	269	*/
	270	int suspend_cpu_hotplug;
	271	EXPORT_SYMBOL(suspend_cpu_hotplug);
	272
e3920fb4 RW	273	static cpumask_t frozen_cpus;
	274
	275	int disable_nonboot_cpus(void)
	276	{
e1d9fd2e	277	int cpu, first_cpu, error = 0;
e3920fb4 RW	278
e3920fb4 RW	279	mutex_lock(&cpu_add_remove_lock);
1d64b9cb RW	280	suspend_cpu_hotplug = 1;
1d64b9cb RW	281	first_cpu = first_cpu(cpu_online_map);
e3920fb4 RW	282	/* We take down all of the non-boot CPUs in one shot to avoid races
	283	* with the userspace trying to use the CPU hotplug at the same time
	284	*/
	285	cpus_clear(frozen_cpus);
	286	printk("Disabling non-boot CPUs ...\n");
	287	for_each_online_cpu(cpu) {
	288	if (cpu == first_cpu)
	289	continue;
	290	error = _cpu_down(cpu);
	291	if (!error) {
	292	cpu_set(cpu, frozen_cpus);
	293	printk("CPU%d is down\n", cpu);
	294	} else {
	295	printk(KERN_ERR "Error taking CPU%d down: %d\n",
	296	cpu, error);
	297	break;
	298	}
	299	}
	300	if (!error) {
	301	BUG_ON(num_online_cpus() > 1);
	302	/* Make sure the CPUs won't be enabled by someone else */
	303	cpu_hotplug_disabled = 1;
	304	} else {
e1d9fd2e	305	printk(KERN_ERR "Non-boot CPUs are not disabled\n");
e3920fb4	306	}
1d64b9cb	307	suspend_cpu_hotplug = 0;
aa953877	308	mutex_unlock(&cpu_add_remove_lock);
e3920fb4 RW	309	return error;
	310	}
	311
	312	void enable_nonboot_cpus(void)
	313	{
	314	int cpu, error;
	315
	316	/* Allow everyone to use the CPU hotplug again */
	317	mutex_lock(&cpu_add_remove_lock);
	318	cpu_hotplug_disabled = 0;
ed746e3b	319	if (cpus_empty(frozen_cpus))
1d64b9cb	320	goto out;
e3920fb4	321
1d64b9cb	322	suspend_cpu_hotplug = 1;
e3920fb4 RW	323	printk("Enabling non-boot CPUs ...\n");
e3920fb4 RW	324	for_each_cpu_mask(cpu, frozen_cpus) {
1d64b9cb	325	error = _cpu_up(cpu);
e3920fb4 RW	326	if (!error) {
	327	printk("CPU%d is up\n", cpu);
	328	continue;
	329	}
1d64b9cb	330	printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error);
e3920fb4 RW	331	}
e3920fb4 RW	332	cpus_clear(frozen_cpus);
1d64b9cb RW	333	suspend_cpu_hotplug = 0;
	334	out:
	335	mutex_unlock(&cpu_add_remove_lock);
1da177e4	336	}
e3920fb4	337	#endif