[GitHub/mt8127/android_kernel_alcatel_ttab.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>

/* Serializes the updates to cpu_online_map, cpu_present_map */
static DEFINE_MUTEX(cpu_add_remove_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;

static struct {
	struct task_struct *active_writer;
	struct mutex lock; /* Synchronizes accesses to refcount, */
	/*
	 * Also blocks the new readers during
	 * an ongoing cpu hotplug operation.
	 */
	int refcount;
} cpu_hotplug;

void __init cpu_hotplug_init(void)
{
	cpu_hotplug.active_writer = NULL;
	mutex_init(&cpu_hotplug.lock);
	cpu_hotplug.refcount = 0;
}

#ifdef CONFIG_HOTPLUG_CPU

void get_online_cpus(void)
{
	might_sleep();
	if (cpu_hotplug.active_writer == current)
		return;
	mutex_lock(&cpu_hotplug.lock);
	cpu_hotplug.refcount++;
	mutex_unlock(&cpu_hotplug.lock);

}
EXPORT_SYMBOL_GPL(get_online_cpus);

void put_online_cpus(void)
{
	if (cpu_hotplug.active_writer == current)
		return;
	mutex_lock(&cpu_hotplug.lock);
	if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
		wake_up_process(cpu_hotplug.active_writer);
	mutex_unlock(&cpu_hotplug.lock);

}
EXPORT_SYMBOL_GPL(put_online_cpus);

#endif	/* CONFIG_HOTPLUG_CPU */

/*
 * The following two API's must be used when attempting
 * to serialize the updates to cpu_online_map, cpu_present_map.
 */
void cpu_maps_update_begin(void)
{
	mutex_lock(&cpu_add_remove_lock);
}

void cpu_maps_update_done(void)
{
	mutex_unlock(&cpu_add_remove_lock);
}

/*
 * This ensures that the hotplug operation can begin only when the
 * refcount goes to zero.
 *
 * Note that during a cpu-hotplug operation, the new readers, if any,
 * will be blocked by the cpu_hotplug.lock
 *
 * Since cpu_hotplug_begin() is always called after invoking
 * cpu_maps_update_begin(), we can be sure that only one writer is active.
 *
 * Note that theoretically, there is a possibility of a livelock:
 * - Refcount goes to zero, last reader wakes up the sleeping
 *   writer.
 * - Last reader unlocks the cpu_hotplug.lock.
 * - A new reader arrives at this moment, bumps up the refcount.
 * - The writer acquires the cpu_hotplug.lock finds the refcount
 *   non zero and goes to sleep again.
 *
 * However, this is very difficult to achieve in practice since
 * get_online_cpus() not an api which is called all that often.
 *
 */
static void cpu_hotplug_begin(void)
{
	cpu_hotplug.active_writer = current;

	for (;;) {
		mutex_lock(&cpu_hotplug.lock);
		if (likely(!cpu_hotplug.refcount))
			break;
		__set_current_state(TASK_UNINTERRUPTIBLE);
		mutex_unlock(&cpu_hotplug.lock);
		schedule();
	}
}

static void cpu_hotplug_done(void)
{
	cpu_hotplug.active_writer = NULL;
	mutex_unlock(&cpu_hotplug.lock);
}
/* Need to know about CPUs going up/down? */
int __ref register_cpu_notifier(struct notifier_block *nb)
{
	int ret;
	cpu_maps_update_begin();
	ret = raw_notifier_chain_register(&cpu_chain, nb);
	cpu_maps_update_done();
	return ret;
}

#ifdef CONFIG_HOTPLUG_CPU

EXPORT_SYMBOL(register_cpu_notifier);

void __ref unregister_cpu_notifier(struct notifier_block *nb)
{
	cpu_maps_update_begin();
	raw_notifier_chain_unregister(&cpu_chain, nb);
	cpu_maps_update_done();
}
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, task_pid_nr(p), cpu,
				 p->state, p->flags);
	}
	write_unlock_irq(&tasklist_lock);
}

struct take_cpu_down_param {
	unsigned long mod;
	void *hcpu;
};

/* Take this CPU down. */
static int __ref take_cpu_down(void *_param)
{
	struct take_cpu_down_param *param = _param;
	int err;

	raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
				param->hcpu);
	/* 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 __ref _cpu_down(unsigned int cpu, int tasks_frozen)
{
	int err, nr_calls = 0;
	struct task_struct *p;
	cpumask_t old_allowed, tmp;
	void *hcpu = (void *)(long)cpu;
	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
	struct take_cpu_down_param tcd_param = {
		.mod = mod,
		.hcpu = hcpu,
	};

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

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

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

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

	p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);

	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 | mod,
					    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);

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

	check_for_tasks(cpu);

out_thread:
	err = kthread_stop(p);
out_allowed:
	set_cpus_allowed_ptr(current, &old_allowed);
out_release:
	cpu_hotplug_done();
	return err;
}

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

	cpu_maps_update_begin();
	if (cpu_hotplug_disabled)
		err = -EBUSY;
	else
		err = _cpu_down(cpu, 0);

	cpu_maps_update_done();
	return err;
}
#endif /*CONFIG_HOTPLUG_CPU*/

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

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

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

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

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

out_notify:
	if (ret != 0)
		__raw_notifier_call_chain(&cpu_chain,
				CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
	cpu_hotplug_done();

	return ret;
}

int __cpuinit cpu_up(unsigned int cpu)
{
	int err = 0;
	if (!cpu_isset(cpu, cpu_possible_map)) {
		printk(KERN_ERR "can't online cpu %d because it is not "
			"configured as may-hotadd at boot time\n", cpu);
#if defined(CONFIG_IA64) || defined(CONFIG_X86_64) || defined(CONFIG_S390)
		printk(KERN_ERR "please check additional_cpus= boot "
				"parameter\n");
#endif
		return -EINVAL;
	}

	cpu_maps_update_begin();
	if (cpu_hotplug_disabled)
		err = -EBUSY;
	else
		err = _cpu_up(cpu, 0);

	cpu_maps_update_done();
	return err;
}

#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_t frozen_cpus;

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

	cpu_maps_update_begin();
	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, 1);
		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");
	}
	cpu_maps_update_done();
	return error;
}

void __ref enable_nonboot_cpus(void)
{
	int cpu, error;

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

	printk("Enabling non-boot CPUs ...\n");
	for_each_cpu_mask(cpu, frozen_cpus) {
		error = _cpu_up(cpu, 1);
		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);
out:
	cpu_maps_update_done();
}
#endif /* CONFIG_PM_SLEEP_SMP */
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	17
d221938c	18	/* Serializes the updates to cpu_online_map, cpu_present_map */
aa953877	19	static DEFINE_MUTEX(cpu_add_remove_lock);
1da177e4	20
bd5349cf	21	static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
1da177e4	22
e3920fb4 RW	23	/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
	24	* Should always be manipulated under cpu_add_remove_lock
	25	*/
	26	static int cpu_hotplug_disabled;
	27
d221938c GS	28	static struct {
	29	struct task_struct *active_writer;
	30	struct mutex lock; /* Synchronizes accesses to refcount, */
	31	/*
	32	* Also blocks the new readers during
	33	* an ongoing cpu hotplug operation.
	34	*/
	35	int refcount;
d221938c	36	} cpu_hotplug;
90d45d17	37
d221938c GS	38	void __init cpu_hotplug_init(void)
	39	{
	40	cpu_hotplug.active_writer = NULL;
	41	mutex_init(&cpu_hotplug.lock);
	42	cpu_hotplug.refcount = 0;
d221938c GS	43	}
	44
	45	#ifdef CONFIG_HOTPLUG_CPU
90d45d17	46
86ef5c9a	47	void get_online_cpus(void)
a9d9baa1	48	{
d221938c GS	49	might_sleep();
d221938c GS	50	if (cpu_hotplug.active_writer == current)
aa953877	51	return;
d221938c GS	52	mutex_lock(&cpu_hotplug.lock);
	53	cpu_hotplug.refcount++;
	54	mutex_unlock(&cpu_hotplug.lock);
	55
a9d9baa1	56	}
86ef5c9a	57	EXPORT_SYMBOL_GPL(get_online_cpus);
90d45d17	58
86ef5c9a	59	void put_online_cpus(void)
a9d9baa1	60	{
d221938c	61	if (cpu_hotplug.active_writer == current)
aa953877	62	return;
d221938c	63	mutex_lock(&cpu_hotplug.lock);
d2ba7e2a ON	64	if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
d2ba7e2a ON	65	wake_up_process(cpu_hotplug.active_writer);
d221938c GS	66	mutex_unlock(&cpu_hotplug.lock);
d221938c GS	67
a9d9baa1	68	}
86ef5c9a	69	EXPORT_SYMBOL_GPL(put_online_cpus);
a9d9baa1	70
a9d9baa1	71	#endif /* CONFIG_HOTPLUG_CPU */
90d45d17	72
d221938c GS	73	/*
	74	* The following two API's must be used when attempting
	75	* to serialize the updates to cpu_online_map, cpu_present_map.
	76	*/
	77	void cpu_maps_update_begin(void)
	78	{
	79	mutex_lock(&cpu_add_remove_lock);
	80	}
	81
	82	void cpu_maps_update_done(void)
	83	{
	84	mutex_unlock(&cpu_add_remove_lock);
	85	}
	86
	87	/*
	88	* This ensures that the hotplug operation can begin only when the
	89	* refcount goes to zero.
	90	*
	91	* Note that during a cpu-hotplug operation, the new readers, if any,
	92	* will be blocked by the cpu_hotplug.lock
	93	*
d2ba7e2a ON	94	* Since cpu_hotplug_begin() is always called after invoking
d2ba7e2a ON	95	* cpu_maps_update_begin(), we can be sure that only one writer is active.
d221938c GS	96	*
	97	* Note that theoretically, there is a possibility of a livelock:
	98	* - Refcount goes to zero, last reader wakes up the sleeping
	99	* writer.
	100	* - Last reader unlocks the cpu_hotplug.lock.
	101	* - A new reader arrives at this moment, bumps up the refcount.
	102	* - The writer acquires the cpu_hotplug.lock finds the refcount
	103	* non zero and goes to sleep again.
	104	*
	105	* However, this is very difficult to achieve in practice since
86ef5c9a	106	* get_online_cpus() not an api which is called all that often.
d221938c GS	107	*
	108	*/
	109	static void cpu_hotplug_begin(void)
	110	{
d221938c	111	cpu_hotplug.active_writer = current;
d2ba7e2a ON	112
	113	for (;;) {
	114	mutex_lock(&cpu_hotplug.lock);
	115	if (likely(!cpu_hotplug.refcount))
	116	break;
	117	__set_current_state(TASK_UNINTERRUPTIBLE);
d221938c GS	118	mutex_unlock(&cpu_hotplug.lock);
d221938c GS	119	schedule();
d221938c	120	}
d221938c GS	121	}
	122
	123	static void cpu_hotplug_done(void)
	124	{
	125	cpu_hotplug.active_writer = NULL;
	126	mutex_unlock(&cpu_hotplug.lock);
	127	}
1da177e4	128	/* Need to know about CPUs going up/down? */
f7b16c10	129	int __ref register_cpu_notifier(struct notifier_block *nb)
1da177e4	130	{
bd5349cf	131	int ret;
d221938c	132	cpu_maps_update_begin();
bd5349cf	133	ret = raw_notifier_chain_register(&cpu_chain, nb);
d221938c	134	cpu_maps_update_done();
bd5349cf	135	return ret;
1da177e4	136	}
65edc68c CS	137
	138	#ifdef CONFIG_HOTPLUG_CPU
	139
1da177e4 LT	140	EXPORT_SYMBOL(register_cpu_notifier);
1da177e4 LT	141
9647155f	142	void __ref unregister_cpu_notifier(struct notifier_block *nb)
1da177e4	143	{
d221938c	144	cpu_maps_update_begin();
bd5349cf	145	raw_notifier_chain_unregister(&cpu_chain, nb);
d221938c	146	cpu_maps_update_done();
1da177e4 LT	147	}
	148	EXPORT_SYMBOL(unregister_cpu_notifier);
	149
1da177e4 LT	150	static inline void check_for_tasks(int cpu)
	151	{
	152	struct task_struct *p;
	153
	154	write_lock_irq(&tasklist_lock);
	155	for_each_process(p) {
	156	if (task_cpu(p) == cpu &&
	157	(!cputime_eq(p->utime, cputime_zero) \|\|
	158	!cputime_eq(p->stime, cputime_zero)))
	159	printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
e7407dcc	160	(state = %ld, flags = %x) \n",
ba25f9dc PE	161	p->comm, task_pid_nr(p), cpu,
ba25f9dc PE	162	p->state, p->flags);
1da177e4 LT	163	}
	164	write_unlock_irq(&tasklist_lock);
	165	}
	166
db912f96 AK	167	struct take_cpu_down_param {
	168	unsigned long mod;
	169	void *hcpu;
	170	};
	171
1da177e4	172	/* Take this CPU down. */
514a20a5	173	static int __ref take_cpu_down(void *_param)
1da177e4	174	{
db912f96	175	struct take_cpu_down_param *param = _param;
1da177e4 LT	176	int err;
1da177e4 LT	177
db912f96 AK	178	raw_notifier_call_chain(&cpu_chain, CPU_DYING \| param->mod,
db912f96 AK	179	param->hcpu);
1da177e4 LT	180	/* Ensure this CPU doesn't handle any more interrupts. */
	181	err = __cpu_disable();
	182	if (err < 0)
f3705136	183	return err;
1da177e4	184
f3705136 ZM	185	/* Force idle task to run as soon as we yield: it should
	186	immediately notice cpu is offline and die quickly. */
	187	sched_idle_next();
	188	return 0;
1da177e4 LT	189	}
1da177e4 LT	190
e3920fb4	191	/* Requires cpu_add_remove_lock to be held */
514a20a5	192	static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
1da177e4	193	{
e7407dcc	194	int err, nr_calls = 0;
1da177e4 LT	195	struct task_struct *p;
1da177e4 LT	196	cpumask_t old_allowed, tmp;
e7407dcc	197	void hcpu = (void )(long)cpu;
8bb78442	198	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
db912f96 AK	199	struct take_cpu_down_param tcd_param = {
	200	.mod = mod,
	201	.hcpu = hcpu,
	202	};
1da177e4	203
e3920fb4 RW	204	if (num_online_cpus() == 1)
e3920fb4 RW	205	return -EBUSY;
1da177e4	206
e3920fb4 RW	207	if (!cpu_online(cpu))
e3920fb4 RW	208	return -EINVAL;
1da177e4	209
d221938c	210	cpu_hotplug_begin();
8bb78442	211	err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE \| mod,
e7407dcc	212	hcpu, -1, &nr_calls);
1da177e4	213	if (err == NOTIFY_BAD) {
a0d8cdb6	214	nr_calls--;
8bb78442 RW	215	__raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED \| mod,
8bb78442 RW	216	hcpu, nr_calls, NULL);
1da177e4	217	printk("%s: attempt to take down CPU %u failed\n",
af1f16d0	218	__func__, cpu);
baaca49f GS	219	err = -EINVAL;
baaca49f GS	220	goto out_release;
1da177e4 LT	221	}
	222
	223	/* Ensure that we are not runnable on dying cpu */
	224	old_allowed = current->cpus_allowed;
f70316da	225	cpus_setall(tmp);
1da177e4	226	cpu_clear(cpu, tmp);
f70316da	227	set_cpus_allowed_ptr(current, &tmp);
1da177e4	228
db912f96	229	p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
aa953877	230
8fa1d7d3	231	if (IS_ERR(p) \|\| cpu_online(cpu)) {
1da177e4	232	/* CPU didn't die: tell everyone. Can't complain. */
8bb78442	233	if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED \| mod,
e7407dcc	234	hcpu) == NOTIFY_BAD)
1da177e4 LT	235	BUG();
1da177e4 LT	236
8fa1d7d3 ST	237	if (IS_ERR(p)) {
	238	err = PTR_ERR(p);
	239	goto out_allowed;
	240	}
1da177e4	241	goto out_thread;
8fa1d7d3	242	}
1da177e4 LT	243
	244	/* Wait for it to sleep (leaving idle task). */
	245	while (!idle_cpu(cpu))
	246	yield();
	247
	248	/* This actually kills the CPU. */
	249	__cpu_die(cpu);
	250
1da177e4	251	/* CPU is completely dead: tell everyone. Too late to complain. */
8bb78442 RW	252	if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD \| mod,
8bb78442 RW	253	hcpu) == NOTIFY_BAD)
1da177e4 LT	254	BUG();
	255
	256	check_for_tasks(cpu);
	257
	258	out_thread:
	259	err = kthread_stop(p);
	260	out_allowed:
f70316da	261	set_cpus_allowed_ptr(current, &old_allowed);
baaca49f	262	out_release:
d221938c	263	cpu_hotplug_done();
e3920fb4 RW	264	return err;
	265	}
	266
514a20a5	267	int __ref cpu_down(unsigned int cpu)
e3920fb4 RW	268	{
	269	int err = 0;
	270
d221938c	271	cpu_maps_update_begin();
e3920fb4 RW	272	if (cpu_hotplug_disabled)
	273	err = -EBUSY;
	274	else
8bb78442	275	err = _cpu_down(cpu, 0);
e3920fb4	276
d221938c	277	cpu_maps_update_done();
1da177e4 LT	278	return err;
	279	}
	280	#endif /CONFIG_HOTPLUG_CPU/
	281
e3920fb4	282	/* Requires cpu_add_remove_lock to be held */
8bb78442	283	static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
1da177e4	284	{
baaca49f	285	int ret, nr_calls = 0;
1da177e4	286	void hcpu = (void )(long)cpu;
8bb78442	287	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
1da177e4	288
e3920fb4 RW	289	if (cpu_online(cpu) \|\| !cpu_present(cpu))
e3920fb4 RW	290	return -EINVAL;
90d45d17	291
d221938c	292	cpu_hotplug_begin();
8bb78442	293	ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE \| mod, hcpu,
baaca49f	294	-1, &nr_calls);
1da177e4	295	if (ret == NOTIFY_BAD) {
a0d8cdb6	296	nr_calls--;
1da177e4	297	printk("%s: attempt to bring up CPU %u failed\n",
af1f16d0	298	__func__, cpu);
1da177e4 LT	299	ret = -EINVAL;
	300	goto out_notify;
	301	}
	302
	303	/* Arch-specific enabling code. */
	304	ret = __cpu_up(cpu);
	305	if (ret != 0)
	306	goto out_notify;
6978c705	307	BUG_ON(!cpu_online(cpu));
1da177e4 LT	308
1da177e4 LT	309	/* Now call notifier in preparation. */
8bb78442	310	raw_notifier_call_chain(&cpu_chain, CPU_ONLINE \| mod, hcpu);
1da177e4 LT	311
	312	out_notify:
	313	if (ret != 0)
baaca49f	314	__raw_notifier_call_chain(&cpu_chain,
8bb78442	315	CPU_UP_CANCELED \| mod, hcpu, nr_calls, NULL);
d221938c	316	cpu_hotplug_done();
e3920fb4 RW	317
	318	return ret;
	319	}
	320
b282b6f8	321	int __cpuinit cpu_up(unsigned int cpu)
e3920fb4 RW	322	{
e3920fb4 RW	323	int err = 0;
73e753a5 KH	324	if (!cpu_isset(cpu, cpu_possible_map)) {
	325	printk(KERN_ERR "can't online cpu %d because it is not "
	326	"configured as may-hotadd at boot time\n", cpu);
	327	#if defined(CONFIG_IA64) \|\| defined(CONFIG_X86_64) \|\| defined(CONFIG_S390)
	328	printk(KERN_ERR "please check additional_cpus= boot "
	329	"parameter\n");
	330	#endif
	331	return -EINVAL;
	332	}
e3920fb4	333
d221938c	334	cpu_maps_update_begin();
e3920fb4 RW	335	if (cpu_hotplug_disabled)
	336	err = -EBUSY;
	337	else
8bb78442	338	err = _cpu_up(cpu, 0);
e3920fb4	339
d221938c	340	cpu_maps_update_done();
e3920fb4 RW	341	return err;
	342	}
	343
f3de4be9	344	#ifdef CONFIG_PM_SLEEP_SMP
e3920fb4 RW	345	static cpumask_t frozen_cpus;
	346
	347	int disable_nonboot_cpus(void)
	348	{
e1d9fd2e	349	int cpu, first_cpu, error = 0;
e3920fb4	350
d221938c	351	cpu_maps_update_begin();
1d64b9cb	352	first_cpu = first_cpu(cpu_online_map);
e3920fb4 RW	353	/* We take down all of the non-boot CPUs in one shot to avoid races
	354	* with the userspace trying to use the CPU hotplug at the same time
	355	*/
	356	cpus_clear(frozen_cpus);
	357	printk("Disabling non-boot CPUs ...\n");
	358	for_each_online_cpu(cpu) {
	359	if (cpu == first_cpu)
	360	continue;
8bb78442	361	error = _cpu_down(cpu, 1);
e3920fb4 RW	362	if (!error) {
	363	cpu_set(cpu, frozen_cpus);
	364	printk("CPU%d is down\n", cpu);
	365	} else {
	366	printk(KERN_ERR "Error taking CPU%d down: %d\n",
	367	cpu, error);
	368	break;
	369	}
	370	}
	371	if (!error) {
	372	BUG_ON(num_online_cpus() > 1);
	373	/* Make sure the CPUs won't be enabled by someone else */
	374	cpu_hotplug_disabled = 1;
	375	} else {
e1d9fd2e	376	printk(KERN_ERR "Non-boot CPUs are not disabled\n");
e3920fb4	377	}
d221938c	378	cpu_maps_update_done();
e3920fb4 RW	379	return error;
	380	}
	381
fa7303e2	382	void __ref enable_nonboot_cpus(void)
e3920fb4 RW	383	{
	384	int cpu, error;
	385
	386	/* Allow everyone to use the CPU hotplug again */
d221938c	387	cpu_maps_update_begin();
e3920fb4	388	cpu_hotplug_disabled = 0;
ed746e3b	389	if (cpus_empty(frozen_cpus))
1d64b9cb	390	goto out;
e3920fb4 RW	391
	392	printk("Enabling non-boot CPUs ...\n");
	393	for_each_cpu_mask(cpu, frozen_cpus) {
8bb78442	394	error = _cpu_up(cpu, 1);
e3920fb4 RW	395	if (!error) {
	396	printk("CPU%d is up\n", cpu);
	397	continue;
	398	}
1d64b9cb	399	printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error);
e3920fb4 RW	400	}
e3920fb4 RW	401	cpus_clear(frozen_cpus);
1d64b9cb	402	out:
d221938c	403	cpu_maps_update_done();
1da177e4	404	}
f3de4be9	405	#endif /* CONFIG_PM_SLEEP_SMP */