Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...

19 files changed, 350 insertions, 739 deletions

diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 37dc0fe1093f..46730017b3c5 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -757,19 +757,18 @@ EXPORT_SYMBOL_GPL(bL_switcher_put_enabled);
  * while the switcher is active.
  * We're just not ready to deal with that given the trickery involved.
  */
-static int bL_switcher_hotplug_callback(struct notifier_block *nfb,
-					unsigned long action, void *hcpu)
+static int bL_switcher_cpu_pre(unsigned int cpu)
 {
-	if (bL_switcher_active) {
-		int pairing = bL_switcher_cpu_pairing[(unsigned long)hcpu];
-		switch (action & 0xf) {
-		case CPU_UP_PREPARE:
-		case CPU_DOWN_PREPARE:
-			if (pairing == -1)
-				return NOTIFY_BAD;
-		}
-	}
-	return NOTIFY_DONE;
+	int pairing;
+
+	if (!bL_switcher_active)
+		return 0;
+
+	pairing = bL_switcher_cpu_pairing[cpu];
+
+	if (pairing == -1)
+		return -EINVAL;
+	return 0;
 }
 
 static bool no_bL_switcher;
@@ -782,8 +781,15 @@ static int __init bL_switcher_init(void)
 	if (!mcpm_is_available())
 		return -ENODEV;
 
-	cpu_notifier(bL_switcher_hotplug_callback, 0);
-
+	cpuhp_setup_state_nocalls(CPUHP_ARM_BL_PREPARE, "arm/bl:prepare",
+				  bL_switcher_cpu_pre, NULL);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "arm/bl:predown",
+					NULL, bL_switcher_cpu_pre);
+	if (ret < 0) {
+		cpuhp_remove_state_nocalls(CPUHP_ARM_BL_PREPARE);
+		pr_err("bL_switcher: Failed to allocate a hotplug state\n");
+		return ret;
+	}
 	if (!no_bL_switcher) {
 		ret = bL_switcher_enable();
 		if (ret)
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index b8df45883cf7..188180b5523d 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -925,9 +925,9 @@ static bool core_has_os_save_restore(void)
 	}
 }
 
-static void reset_ctrl_regs(void *unused)
+static void reset_ctrl_regs(unsigned int cpu)
 {
-	int i, raw_num_brps, err = 0, cpu = smp_processor_id();
+	int i, raw_num_brps, err = 0;
 	u32 val;
 
 	/*
@@ -1020,25 +1020,20 @@ out_mdbgen:
 		cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu));
 }
 
-static int dbg_reset_notify(struct notifier_block *self,
-				      unsigned long action, void *cpu)
+static int dbg_reset_online(unsigned int cpu)
 {
-	if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE)
-		smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1);
-
-	return NOTIFY_OK;
+	local_irq_disable();
+	reset_ctrl_regs(cpu);
+	local_irq_enable();
+	return 0;
 }
 
-static struct notifier_block dbg_reset_nb = {
-	.notifier_call = dbg_reset_notify,
-};
-
 #ifdef CONFIG_CPU_PM
 static int dbg_cpu_pm_notify(struct notifier_block *self, unsigned long action,
 			     void *v)
 {
 	if (action == CPU_PM_EXIT)
-		reset_ctrl_regs(NULL);
+		reset_ctrl_regs(smp_processor_id());
 
 	return NOTIFY_OK;
 }
@@ -1059,6 +1054,8 @@ static inline void pm_init(void)
 
 static int __init arch_hw_breakpoint_init(void)
 {
+	int ret;
+
 	debug_arch = get_debug_arch();
 
 	if (!debug_arch_supported()) {
@@ -1072,25 +1069,28 @@ static int __init arch_hw_breakpoint_init(void)
 	core_num_brps = get_num_brps();
 	core_num_wrps = get_num_wrps();
 
-	cpu_notifier_register_begin();
-
 	/*
 	 * We need to tread carefully here because DBGSWENABLE may be
 	 * driven low on this core and there isn't an architected way to
 	 * determine that.
 	 */
+	get_online_cpus();
 	register_undef_hook(&debug_reg_hook);
 
 	/*
-	 * Reset the breakpoint resources. We assume that a halting
-	 * debugger will leave the world in a nice state for us.
+	 * Register CPU notifier which resets the breakpoint resources. We
+	 * assume that a halting debugger will leave the world in a nice state
+	 * for us.
 	 */
-	on_each_cpu(reset_ctrl_regs, NULL, 1);
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online",
+				dbg_reset_online, NULL);
 	unregister_undef_hook(&debug_reg_hook);
-	if (!cpumask_empty(&debug_err_mask)) {
+	if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) {
 		core_num_brps = 0;
 		core_num_wrps = 0;
-		cpu_notifier_register_done();
+		if (ret > 0)
+			cpuhp_remove_state_nocalls(ret);
+		put_online_cpus();
 		return 0;
 	}
 
@@ -1108,12 +1108,9 @@ static int __init arch_hw_breakpoint_init(void)
 			TRAP_HWBKPT, "watchpoint debug exception");
 	hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,
 			TRAP_HWBKPT, "breakpoint debug exception");
+	put_online_cpus();
 
-	/* Register hotplug and PM notifiers. */
-	__register_cpu_notifier(&dbg_reset_nb);
-
-	cpu_notifier_register_done();
-
+	/* Register PM notifiers. */
 	pm_init();
 	return 0;
 }
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index b3d5b3e8fbcb..7b7be71e87bf 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -227,7 +227,7 @@ static struct attribute_group cpuregs_attr_group = {
 	.name = "identification"
 };
 
-static int cpuid_add_regs(int cpu)
+static int cpuid_cpu_online(unsigned int cpu)
 {
 	int rc;
 	struct device *dev;
@@ -248,7 +248,7 @@ out:
 	return rc;
 }
 
-static int cpuid_remove_regs(int cpu)
+static int cpuid_cpu_offline(unsigned int cpu)
 {
 	struct device *dev;
 	struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
@@ -264,40 +264,22 @@ static int cpuid_remove_regs(int cpu)
 	return 0;
 }
 
-static int cpuid_callback(struct notifier_block *nb,
-			 unsigned long action, void *hcpu)
-{
-	int rc = 0;
-	unsigned long cpu = (unsigned long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		rc = cpuid_add_regs(cpu);
-		break;
-	case CPU_DEAD:
-		rc = cpuid_remove_regs(cpu);
-		break;
-	}
-
-	return notifier_from_errno(rc);
-}
-
 static int __init cpuinfo_regs_init(void)
 {
-	int cpu;
-
-	cpu_notifier_register_begin();
+	int cpu, ret;
 
 	for_each_possible_cpu(cpu) {
 		struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 
 		kobject_init(&info->kobj, &cpuregs_kobj_type);
-		if (cpu_online(cpu))
-			cpuid_add_regs(cpu);
 	}
-	__hotcpu_notifier(cpuid_callback, 0);
 
-	cpu_notifier_register_done();
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/cpuinfo:online",
+				cpuid_cpu_online, cpuid_cpu_offline);
+	if (ret < 0) {
+		pr_err("cpuinfo: failed to register hotplug callbacks.\n");
+		return ret;
+	}
 	return 0;
 }
 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c
index 5ed0ea92c5bf..85bba43e7d5d 100644
--- a/arch/ia64/kernel/err_inject.c
+++ b/arch/ia64/kernel/err_inject.c
@@ -224,85 +224,45 @@ static struct attribute_group err_inject_attr_group = {
 	.name = "err_inject"
 };
 /* Add/Remove err_inject interface for CPU device */
-static int err_inject_add_dev(struct device *sys_dev)
+static int err_inject_add_dev(unsigned int cpu)
 {
+	struct device *sys_dev = get_cpu_device(cpu);
+
 	return sysfs_create_group(&sys_dev->kobj, &err_inject_attr_group);
 }
 
-static int err_inject_remove_dev(struct device *sys_dev)
+static int err_inject_remove_dev(unsigned int cpu)
 {
+	struct device *sys_dev = get_cpu_device(cpu);
+
 	sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
 	return 0;
 }
-static int err_inject_cpu_callback(struct notifier_block *nfb,
-		unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *sys_dev;
-
-	sys_dev = get_cpu_device(cpu);
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		err_inject_add_dev(sys_dev);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		err_inject_remove_dev(sys_dev);
-		break;
-	}
-
-	return NOTIFY_OK;
-}
 
-static struct notifier_block err_inject_cpu_notifier =
-{
-	.notifier_call = err_inject_cpu_callback,
-};
+static enum cpuhp_state hp_online;
 
-static int __init
-err_inject_init(void)
+static int __init err_inject_init(void)
 {
-	int i;
-
+	int ret;
 #ifdef ERR_INJ_DEBUG
 	printk(KERN_INFO "Enter error injection driver.\n");
 #endif
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		err_inject_cpu_callback(&err_inject_cpu_notifier, CPU_ONLINE,
-				(void *)(long)i);
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/err_inj:online",
+				err_inject_add_dev, err_inject_remove_dev);
+	if (ret >= 0) {
+		hp_online = ret;
+		ret = 0;
 	}
-
-	__register_hotcpu_notifier(&err_inject_cpu_notifier);
-
-	cpu_notifier_register_done();
-
-	return 0;
+	return ret;
 }
 
-static void __exit
-err_inject_exit(void)
+static void __exit err_inject_exit(void)
 {
-	int i;
-	struct device *sys_dev;
-
 #ifdef ERR_INJ_DEBUG
 	printk(KERN_INFO "Exit error injection driver.\n");
 #endif
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		sys_dev = get_cpu_device(i);
-		sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
-	}
-
-	__unregister_hotcpu_notifier(&err_inject_cpu_notifier);
-
-	cpu_notifier_register_done();
+	cpuhp_remove_state(hp_online);
 }
 
 module_init(err_inject_init);
diff --git a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
index c39c3cd3ac34..b6e597860888 100644
--- a/arch/ia64/kernel/palinfo.c
+++ b/arch/ia64/kernel/palinfo.c
@@ -932,8 +932,7 @@ static const struct file_operations proc_palinfo_fops = {
 	.release	= single_release,
 };
 
-static void
-create_palinfo_proc_entries(unsigned int cpu)
+static int palinfo_add_proc(unsigned int cpu)
 {
 	pal_func_cpu_u_t f;
 	struct proc_dir_entry *cpu_dir;
@@ -943,7 +942,7 @@ create_palinfo_proc_entries(unsigned int cpu)
 
 	cpu_dir = proc_mkdir(cpustr, palinfo_dir);
 	if (!cpu_dir)
-		return;
+		return -EINVAL;
 
 	f.req_cpu = cpu;
 
@@ -952,42 +951,21 @@ create_palinfo_proc_entries(unsigned int cpu)
 		proc_create_data(palinfo_entries[j].name, 0, cpu_dir,
 				 &proc_palinfo_fops, (void *)f.value);
 	}
+	return 0;
 }
 
-static void
-remove_palinfo_proc_entries(unsigned int hcpu)
+static int palinfo_del_proc(unsigned int hcpu)
 {
 	char cpustr[3+4+1];	/* cpu numbers are up to 4095 on itanic */
+
 	sprintf(cpustr, "cpu%d", hcpu);
 	remove_proc_subtree(cpustr, palinfo_dir);
+	return 0;
 }
 
-static int palinfo_cpu_callback(struct notifier_block *nfb,
-					unsigned long action, void *hcpu)
-{
-	unsigned int hotcpu = (unsigned long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		create_palinfo_proc_entries(hotcpu);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		remove_palinfo_proc_entries(hotcpu);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block __refdata palinfo_cpu_notifier =
-{
-	.notifier_call = palinfo_cpu_callback,
-	.priority = 0,
-};
+static enum cpuhp_state hp_online;
 
-static int __init
-palinfo_init(void)
+static int __init palinfo_init(void)
 {
 	int i = 0;
 
@@ -996,25 +974,19 @@ palinfo_init(void)
 	if (!palinfo_dir)
 		return -ENOMEM;
 
-	cpu_notifier_register_begin();
-
-	/* Create palinfo dirs in /proc for all online cpus */
-	for_each_online_cpu(i) {
-		create_palinfo_proc_entries(i);
+	i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/palinfo:online",
+			      palinfo_add_proc, palinfo_del_proc);
+	if (i < 0) {
+		remove_proc_subtree("pal", NULL);
+		return i;
 	}
-
-	/* Register for future delivery via notify registration */
-	__register_hotcpu_notifier(&palinfo_cpu_notifier);
-
-	cpu_notifier_register_done();
-
+	hp_online = i;
 	return 0;
 }
 
-static void __exit
-palinfo_exit(void)
+static void __exit palinfo_exit(void)
 {
-	unregister_hotcpu_notifier(&palinfo_cpu_notifier);
+	cpuhp_remove_state(hp_online);
 	remove_proc_subtree("pal", NULL);
 }
 
diff --git a/arch/ia64/kernel/salinfo.c b/arch/ia64/kernel/salinfo.c
index 5313007d5423..aaf74f36cfa1 100644
--- a/arch/ia64/kernel/salinfo.c
+++ b/arch/ia64/kernel/salinfo.c
@@ -550,52 +550,40 @@ static const struct file_operations salinfo_data_fops = {
 	.llseek  = default_llseek,
 };
 
-static int
-salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
+static int salinfo_cpu_online(unsigned int cpu)
 {
-	unsigned int i, cpu = (unsigned long)hcpu;
-	unsigned long flags;
+	unsigned int i, end = ARRAY_SIZE(salinfo_data);
 	struct salinfo_data *data;
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		spin_lock_irqsave(&data_saved_lock, flags);
-		for (i = 0, data = salinfo_data;
-		     i < ARRAY_SIZE(salinfo_data);
-		     ++i, ++data) {
-			cpumask_set_cpu(cpu, &data->cpu_event);
-			wake_up_interruptible(&data->read_wait);
-		}
-		spin_unlock_irqrestore(&data_saved_lock, flags);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		spin_lock_irqsave(&data_saved_lock, flags);
-		for (i = 0, data = salinfo_data;
-		     i < ARRAY_SIZE(salinfo_data);
-		     ++i, ++data) {
-			struct salinfo_data_saved *data_saved;
-			int j;
-			for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
-			     j >= 0;
-			     --j, --data_saved) {
-				if (data_saved->buffer && data_saved->cpu == cpu) {
-					shift1_data_saved(data, j);
-				}
-			}
-			cpumask_clear_cpu(cpu, &data->cpu_event);
-		}
-		spin_unlock_irqrestore(&data_saved_lock, flags);
-		break;
+
+	spin_lock_irq(&data_saved_lock);
+	for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+		cpumask_set_cpu(cpu, &data->cpu_event);
+		wake_up_interruptible(&data->read_wait);
 	}
-	return NOTIFY_OK;
+	spin_unlock_irq(&data_saved_lock);
+	return 0;
 }
 
-static struct notifier_block salinfo_cpu_notifier =
+static int salinfo_cpu_pre_down(unsigned int cpu)
 {
-	.notifier_call = salinfo_cpu_callback,
-	.priority = 0,
-};
+	unsigned int i, end = ARRAY_SIZE(salinfo_data);
+	struct salinfo_data *data;
+
+	spin_lock_irq(&data_saved_lock);
+	for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+		struct salinfo_data_saved *data_saved;
+		int j = ARRAY_SIZE(data->data_saved) - 1;
+
+		for (data_saved = data->data_saved + j; j >= 0;
+		     --j, --data_saved) {
+			if (data_saved->buffer && data_saved->cpu == cpu)
+				shift1_data_saved(data, j);
+		}
+		cpumask_clear_cpu(cpu, &data->cpu_event);
+	}
+	spin_unlock_irq(&data_saved_lock);
+	return 0;
+}
 
 static int __init
 salinfo_init(void)
@@ -604,7 +592,7 @@ salinfo_init(void)
 	struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
 	struct proc_dir_entry *dir, *entry;
 	struct salinfo_data *data;
-	int i, j;
+	int i;
 
 	salinfo_dir = proc_mkdir("sal", NULL);
 	if (!salinfo_dir)
@@ -617,8 +605,6 @@ salinfo_init(void)
 					   (void *)salinfo_entries[i].feature);
 	}
 
-	cpu_notifier_register_begin();
-
 	for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
 		data = salinfo_data + i;
 		data->type = i;
@@ -639,10 +625,6 @@ salinfo_init(void)
 			continue;
 		*sdir++ = entry;
 
-		/* we missed any events before now */
-		for_each_online_cpu(j)
-			cpumask_set_cpu(j, &data->cpu_event);
-
 		*sdir++ = dir;
 	}
 
@@ -653,10 +635,9 @@ salinfo_init(void)
 	salinfo_timer.function = &salinfo_timeout;
 	add_timer(&salinfo_timer);
 
-	__register_hotcpu_notifier(&salinfo_cpu_notifier);
-
-	cpu_notifier_register_done();
-
+	i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/salinfo:online",
+			      salinfo_cpu_online, salinfo_cpu_pre_down);
+	WARN_ON(i < 0);
 	return 0;
 }
 
diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c
index c01fe8991244..1a68f012a6dc 100644
--- a/arch/ia64/kernel/topology.c
+++ b/arch/ia64/kernel/topology.c
@@ -349,9 +349,9 @@ static int cpu_cache_sysfs_init(unsigned int cpu)
 }
 
 /* Add cache interface for CPU device */
-static int cache_add_dev(struct device *sys_dev)
+static int cache_add_dev(unsigned int cpu)
 {
-	unsigned int cpu = sys_dev->id;
+	struct device *sys_dev = get_cpu_device(cpu);
 	unsigned long i, j;
 	struct cache_info *this_object;
 	int retval = 0;
@@ -399,9 +399,8 @@ static int cache_add_dev(struct device *sys_dev)
 }
 
 /* Remove cache interface for CPU device */
-static int cache_remove_dev(struct device *sys_dev)
+static int cache_remove_dev(unsigned int cpu)
 {
-	unsigned int cpu = sys_dev->id;
 	unsigned long i;
 
 	for (i = 0; i < all_cpu_cache_info[cpu].num_cache_leaves; i++)
@@ -419,52 +418,13 @@ static int cache_remove_dev(struct device *sys_dev)
 	return 0;
 }
 
-/*
- * When a cpu is hot-plugged, do a check and initiate
- * cache kobject if necessary
- */
-static int cache_cpu_callback(struct notifier_block *nfb,
-		unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *sys_dev;
-
-	sys_dev = get_cpu_device(cpu);
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		cache_add_dev(sys_dev);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		cache_remove_dev(sys_dev);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block cache_cpu_notifier =
-{
-	.notifier_call = cache_cpu_callback
-};
-
 static int __init cache_sysfs_init(void)
 {
-	int i;
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		struct device *sys_dev = get_cpu_device((unsigned int)i);
-		cache_add_dev(sys_dev);
-	}
-
-	__register_hotcpu_notifier(&cache_cpu_notifier);
-
-	cpu_notifier_register_done();
+	int ret;
 
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/topology:online",
+				cache_add_dev, cache_remove_dev);
+	WARN_ON(ret < 0);
 	return 0;
 }
-
 device_initcall(cache_sysfs_init);
-
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index c4f1d1f7bae0..c1fb255a60d6 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -703,7 +703,7 @@ static struct device_attribute pa6t_attrs[] = {
 #endif /* HAS_PPC_PMC_PA6T */
 #endif /* HAS_PPC_PMC_CLASSIC */
 
-static void register_cpu_online(unsigned int cpu)
+static int register_cpu_online(unsigned int cpu)
 {
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
@@ -782,11 +782,12 @@ static void register_cpu_online(unsigned int cpu)
 	}
 #endif
 	cacheinfo_cpu_online(cpu);
+	return 0;
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void unregister_cpu_online(unsigned int cpu)
+static int unregister_cpu_online(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
 	struct device_attribute *attrs, *pmc_attrs;
@@ -863,6 +864,8 @@ static void unregister_cpu_online(unsigned int cpu)
 	}
 #endif
 	cacheinfo_cpu_offline(cpu);
+#endif /* CONFIG_HOTPLUG_CPU */
+	return 0;
 }
 
 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
@@ -883,32 +886,6 @@ ssize_t arch_cpu_release(const char *buf, size_t count)
 }
 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
 
-#endif /* CONFIG_HOTPLUG_CPU */
-
-static int sysfs_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned int)(long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		register_cpu_online(cpu);
-		break;
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		unregister_cpu_online(cpu);
-		break;
-#endif
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block sysfs_cpu_nb = {
-	.notifier_call	= sysfs_cpu_notify,
-};
-
 static DEFINE_MUTEX(cpu_mutex);
 
 int cpu_add_dev_attr(struct device_attribute *attr)
@@ -1023,12 +1000,10 @@ static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL);
 
 static int __init topology_init(void)
 {
-	int cpu;
+	int cpu, r;
 
 	register_nodes();
 
-	cpu_notifier_register_begin();
-
 	for_each_possible_cpu(cpu) {
 		struct cpu *c = &per_cpu(cpu_devices, cpu);
 
@@ -1047,15 +1022,10 @@ static int __init topology_init(void)
 
 			device_create_file(&c->dev, &dev_attr_physical_id);
 		}
-
-		if (cpu_online(cpu))
-			register_cpu_online(cpu);
 	}
-
-	__register_cpu_notifier(&sysfs_cpu_nb);
-
-	cpu_notifier_register_done();
-
+	r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online",
+			      register_cpu_online, unregister_cpu_online);
+	WARN_ON(r < 0);
 #ifdef CONFIG_PPC64
 	sysfs_create_dscr_default();
 #endif /* CONFIG_PPC64 */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 3686471be32b..39ef1f4a7b02 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2254,12 +2254,12 @@ static void post_guest_process(struct kvmppc_vcore *vc, bool is_master)
  * enter the guest. Only do this if it is the primary thread of the
  * core (not if a subcore) that is entering the guest.
  */
-static inline void kvmppc_clear_host_core(int cpu)
+static inline int kvmppc_clear_host_core(unsigned int cpu)
 {
 	int core;
 
 	if (!kvmppc_host_rm_ops_hv || cpu_thread_in_core(cpu))
-		return;
+		return 0;
 	/*
 	 * Memory barrier can be omitted here as we will do a smp_wmb()
 	 * later in kvmppc_start_thread and we need ensure that state is
@@ -2267,6 +2267,7 @@ static inline void kvmppc_clear_host_core(int cpu)
 	 */
 	core = cpu >> threads_shift;
 	kvmppc_host_rm_ops_hv->rm_core[core].rm_state.in_host = 0;
+	return 0;
 }
 
 /*
@@ -2274,12 +2275,12 @@ static inline void kvmppc_clear_host_core(int cpu)
  * Only need to do this if it is the primary thread of the core that is
  * exiting.
  */
-static inline void kvmppc_set_host_core(int cpu)
+static inline int kvmppc_set_host_core(unsigned int cpu)
 {
 	int core;
 
 	if (!kvmppc_host_rm_ops_hv || cpu_thread_in_core(cpu))
-		return;
+		return 0;
 
 	/*
 	 * Memory barrier can be omitted here because we do a spin_unlock
@@ -2287,6 +2288,7 @@ static inline void kvmppc_set_host_core(int cpu)
 	 */
 	core = cpu >> threads_shift;
 	kvmppc_host_rm_ops_hv->rm_core[core].rm_state.in_host = 1;
+	return 0;
 }
 
 /*
@@ -3094,36 +3096,6 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 }
 
 #ifdef CONFIG_KVM_XICS
-static int kvmppc_cpu_notify(struct notifier_block *self, unsigned long action,
-			void *hcpu)
-{
-	unsigned long cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		kvmppc_set_host_core(cpu);
-		break;
-
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-		kvmppc_clear_host_core(cpu);
-		break;
-#endif
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block kvmppc_cpu_notifier = {
-	    .notifier_call = kvmppc_cpu_notify,
-};
-
 /*
  * Allocate a per-core structure for managing state about which cores are
  * running in the host versus the guest and for exchanging data between
@@ -3185,15 +3157,17 @@ void kvmppc_alloc_host_rm_ops(void)
 		return;
 	}
 
-	register_cpu_notifier(&kvmppc_cpu_notifier);
-
+	cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
+				  "ppc/kvm_book3s:prepare",
+				  kvmppc_set_host_core,
+				  kvmppc_clear_host_core);
 	put_online_cpus();
 }
 
 void kvmppc_free_host_rm_ops(void)
 {
 	if (kvmppc_host_rm_ops_hv) {
-		unregister_cpu_notifier(&kvmppc_cpu_notifier);
+		cpuhp_remove_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE);
 		kfree(kvmppc_host_rm_ops_hv->rm_core);
 		kfree(kvmppc_host_rm_ops_hv);
 		kvmppc_host_rm_ops_hv = NULL;
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index b988ed1d75ad..df4a508ff35c 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -1052,22 +1052,18 @@ static struct attribute_group cpu_online_attr_group = {
 	.attrs = cpu_online_attrs,
 };
 
-static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
-			  void *hcpu)
+static int smp_cpu_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned int)(long)hcpu;
 	struct device *s = &per_cpu(cpu_device, cpu)->dev;
-	int err = 0;
 
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
-		break;
-	case CPU_DEAD:
-		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
-		break;
-	}
-	return notifier_from_errno(err);
+	return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
+}
+static int smp_cpu_pre_down(unsigned int cpu)
+{
+	struct device *s = &per_cpu(cpu_device, cpu)->dev;
+
+	sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
+	return 0;
 }
 
 static int smp_add_present_cpu(int cpu)
@@ -1088,20 +1084,12 @@ static int smp_add_present_cpu(int cpu)
 	rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 	if (rc)
 		goto out_cpu;
-	if (cpu_online(cpu)) {
-		rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
-		if (rc)
-			goto out_online;
-	}
 	rc = topology_cpu_init(c);
 	if (rc)
 		goto out_topology;
 	return 0;
 
 out_topology:
-	if (cpu_online(cpu))
-		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
-out_online:
 	sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
 out_cpu:
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1154,17 +1142,15 @@ static int __init s390_smp_init(void)
 	if (rc)
 		return rc;
 #endif
-	cpu_notifier_register_begin();
 	for_each_present_cpu(cpu) {
 		rc = smp_add_present_cpu(cpu);
 		if (rc)
 			goto out;
 	}
 
-	__hotcpu_notifier(smp_cpu_notify, 0);
-
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
+			       smp_cpu_online, smp_cpu_pre_down);
 out:
-	cpu_notifier_register_done();
 	return rc;
 }
 subsys_initcall(s390_smp_init);
diff --git a/arch/sparc/kernel/sysfs.c b/arch/sparc/kernel/sysfs.c
index fa8e21abb5e0..4808b6d23455 100644
--- a/arch/sparc/kernel/sysfs.c
+++ b/arch/sparc/kernel/sysfs.c
@@ -221,7 +221,7 @@ static struct device_attribute cpu_core_attrs[] = {
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
-static void register_cpu_online(unsigned int cpu)
+static int register_cpu_online(unsigned int cpu)
 {
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
@@ -231,11 +231,12 @@ static void register_cpu_online(unsigned int cpu)
 		device_create_file(s, &cpu_core_attrs[i]);
 
 	register_mmu_stats(s);
+	return 0;
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void unregister_cpu_online(unsigned int cpu)
+static int unregister_cpu_online(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
 	int i;
@@ -243,33 +244,10 @@ static void unregister_cpu_online(unsigned int cpu)
 	unregister_mmu_stats(s);
 	for (i = 0; i < ARRAY_SIZE(cpu_core_attrs); i++)
 		device_remove_file(s, &cpu_core_attrs[i]);
-}
-#endif
-
-static int sysfs_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned int)(long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		register_cpu_online(cpu);
-		break;
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		unregister_cpu_online(cpu);
-		break;
 #endif
-	}
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block sysfs_cpu_nb = {
-	.notifier_call	= sysfs_cpu_notify,
-};
-
 static void __init check_mmu_stats(void)
 {
 	unsigned long dummy1, err;
@@ -294,26 +272,21 @@ static void register_nodes(void)
 
 static int __init topology_init(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	register_nodes();
 
 	check_mmu_stats();
 
-	cpu_notifier_register_begin();
-
 	for_each_possible_cpu(cpu) {
 		struct cpu *c = &per_cpu(cpu_devices, cpu);
 
 		register_cpu(c, cpu);
-		if (cpu_online(cpu))
-			register_cpu_online(cpu);
 	}
 
-	__register_cpu_notifier(&sysfs_cpu_nb);
-
-	cpu_notifier_register_done();
-
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "sparc/topology:online",
+				register_cpu_online, unregister_cpu_online);
+	WARN_ON(ret < 0);
 	return 0;
 }
 
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index caab413c91ad..5132f2a6c0a2 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -295,9 +295,7 @@ void do_machine_check(struct pt_regs *, long);
 /*
  * Threshold handler
  */
-
 extern void (*mce_threshold_vector)(void);
-extern void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
 
 /* Deferred error interrupt handler */
 extern void (*deferred_error_int_vector)(void);
@@ -375,6 +373,15 @@ struct smca_bank {
 extern struct smca_bank smca_banks[MAX_NR_BANKS];
 
 extern const char *smca_get_long_name(enum smca_bank_types t);
+
+extern int mce_threshold_create_device(unsigned int cpu);
+extern int mce_threshold_remove_device(unsigned int cpu);
+
+#else
+
+static inline int mce_threshold_create_device(unsigned int cpu) { return 0; };
+static inline int mce_threshold_remove_device(unsigned int cpu) { return 0; };
+
 #endif
 
 #endif /* _ASM_X86_MCE_H */
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a3cb27af4f9b..132e1ec67da0 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1792,6 +1792,14 @@ static void mce_start_timer(unsigned int cpu, struct timer_list *t)
 	add_timer_on(t, cpu);
 }
 
+static void __mcheck_cpu_setup_timer(void)
+{
+	struct timer_list *t = this_cpu_ptr(&mce_timer);
+	unsigned int cpu = smp_processor_id();
+
+	setup_pinned_timer(t, mce_timer_fn, cpu);
+}
+
 static void __mcheck_cpu_init_timer(void)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
@@ -1843,7 +1851,7 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
 	__mcheck_cpu_init_generic();
 	__mcheck_cpu_init_vendor(c);
 	__mcheck_cpu_init_clear_banks();
-	__mcheck_cpu_init_timer();
+	__mcheck_cpu_setup_timer();
 }
 
 /*
@@ -2303,8 +2311,6 @@ static struct bus_type mce_subsys = {
 
 DEFINE_PER_CPU(struct device *, mce_device);
 
-void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
-
 static inline struct mce_bank *attr_to_bank(struct device_attribute *attr)
 {
 	return container_of(attr, struct mce_bank, attr);
@@ -2457,6 +2463,10 @@ static int mce_device_create(unsigned int cpu)
 	if (!mce_available(&boot_cpu_data))
 		return -EIO;
 
+	dev = per_cpu(mce_device, cpu);
+	if (dev)
+		return 0;
+
 	dev = kzalloc(sizeof *dev, GFP_KERNEL);
 	if (!dev)
 		return -ENOMEM;
@@ -2516,28 +2526,25 @@ static void mce_device_remove(unsigned int cpu)
 }
 
 /* Make sure there are no machine checks on offlined CPUs. */
-static void mce_disable_cpu(void *h)
+static void mce_disable_cpu(void)
 {
-	unsigned long action = *(unsigned long *)h;
-
 	if (!mce_available(raw_cpu_ptr(&cpu_info)))
 		return;
 
-	if (!(action & CPU_TASKS_FROZEN))
+	if (!cpuhp_tasks_frozen)
 		cmci_clear();
 
 	vendor_disable_error_reporting();
 }
 
-static void mce_reenable_cpu(void *h)
+static void mce_reenable_cpu(void)
 {
-	unsigned long action = *(unsigned long *)h;
 	int i;
 
 	if (!mce_available(raw_cpu_ptr(&cpu_info)))
 		return;
 
-	if (!(action & CPU_TASKS_FROZEN))
+	if (!cpuhp_tasks_frozen)
 		cmci_reenable();
 	for (i = 0; i < mca_cfg.banks; i++) {
 		struct mce_bank *b = &mce_banks[i];
@@ -2547,45 +2554,43 @@ static void mce_reenable_cpu(void *h)
 	}
 }
 
-/* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+static int mce_cpu_dead(unsigned int cpu)
+{
+	mce_intel_hcpu_update(cpu);
+
+	/* intentionally ignoring frozen here */
+	if (!cpuhp_tasks_frozen)
+		cmci_rediscover();
+	return 0;
+}
+
+static int mce_cpu_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
 	struct timer_list *t = &per_cpu(mce_timer, cpu);
+	int ret;
 
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		mce_device_create(cpu);
-		if (threshold_cpu_callback)
-			threshold_cpu_callback(action, cpu);
-		break;
-	case CPU_DEAD:
-		if (threshold_cpu_callback)
-			threshold_cpu_callback(action, cpu);
-		mce_device_remove(cpu);
-		mce_intel_hcpu_update(cpu);
+	mce_device_create(cpu);
 
-		/* intentionally ignoring frozen here */
-		if (!(action & CPU_TASKS_FROZEN))
-			cmci_rediscover();
-		break;
-	case CPU_DOWN_PREPARE:
-		smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
-		del_timer_sync(t);
-		break;
-	case CPU_DOWN_FAILED:
-		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
-		mce_start_timer(cpu, t);
-		break;
+	ret = mce_threshold_create_device(cpu);
+	if (ret) {
+		mce_device_remove(cpu);
+		return ret;
 	}
-
-	return NOTIFY_OK;
+	mce_reenable_cpu();
+	mce_start_timer(cpu, t);
+	return 0;
 }
 
-static struct notifier_block mce_cpu_notifier = {
-	.notifier_call = mce_cpu_callback,
-};
+static int mce_cpu_pre_down(unsigned int cpu)
+{
+	struct timer_list *t = &per_cpu(mce_timer, cpu);
+
+	mce_disable_cpu();
+	del_timer_sync(t);
+	mce_threshold_remove_device(cpu);
+	mce_device_remove(cpu);
+	return 0;
+}
 
 static __init void mce_init_banks(void)
 {
@@ -2607,8 +2612,8 @@ static __init void mce_init_banks(void)
 
 static __init int mcheck_init_device(void)
 {
+	enum cpuhp_state hp_online;
 	int err;
-	int i = 0;
 
 	if (!mce_available(&boot_cpu_data)) {
 		err = -EIO;
@@ -2626,23 +2631,16 @@ static __init int mcheck_init_device(void)
 	if (err)
 		goto err_out_mem;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i) {
-		err = mce_device_create(i);
-		if (err) {
-			/*
-			 * Register notifier anyway (and do not unreg it) so
-			 * that we don't leave undeleted timers, see notifier
-			 * callback above.
-			 */
-			__register_hotcpu_notifier(&mce_cpu_notifier);
-			cpu_notifier_register_done();
-			goto err_device_create;
-		}
-	}
+	err = cpuhp_setup_state(CPUHP_X86_MCE_DEAD, "x86/mce:dead", NULL,
+				mce_cpu_dead);
+	if (err)
+		goto err_out_mem;
 
-	__register_hotcpu_notifier(&mce_cpu_notifier);
-	cpu_notifier_register_done();
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online",
+				mce_cpu_online, mce_cpu_pre_down);
+	if (err < 0)
+		goto err_out_online;
+	hp_online = err;
 
 	register_syscore_ops(&mce_syscore_ops);
 
@@ -2655,16 +2653,10 @@ static __init int mcheck_init_device(void)
 
 err_register:
 	unregister_syscore_ops(&mce_syscore_ops);
+	cpuhp_remove_state(hp_online);
 
-err_device_create:
-	/*
-	 * We didn't keep track of which devices were created above, but
-	 * even if we had, the set of online cpus might have changed.
-	 * Play safe and remove for every possible cpu, since
-	 * mce_device_remove() will do the right thing.
-	 */
-	for_each_possible_cpu(i)
-		mce_device_remove(i);
+err_out_online:
+	cpuhp_remove_state(CPUHP_X86_MCE_DEAD);
 
 err_out_mem:
 	free_cpumask_var(mce_device_initialized);
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 51ad0086b0bb..ffacfdcacb85 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -54,6 +54,8 @@
 /* Threshold LVT offset is at MSR0xC0000410[15:12] */
 #define SMCA_THR_LVT_OFF	0xF000
 
+static bool thresholding_en;
+
 static const char * const th_names[] = {
 	"load_store",
 	"insn_fetch",
@@ -1235,31 +1237,6 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank)
 	return err;
 }
 
-/* create dir/files for all valid threshold banks */
-static int threshold_create_device(unsigned int cpu)
-{
-	unsigned int bank;
-	struct threshold_bank **bp;
-	int err = 0;
-
-	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
-		     GFP_KERNEL);
-	if (!bp)
-		return -ENOMEM;
-
-	per_cpu(threshold_banks, cpu) = bp;
-
-	for (bank = 0; bank < mca_cfg.banks; ++bank) {
-		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
-			continue;
-		err = threshold_create_bank(cpu, bank);
-		if (err)
-			return err;
-	}
-
-	return err;
-}
-
 static void deallocate_threshold_block(unsigned int cpu,
 						 unsigned int bank)
 {
@@ -1327,48 +1304,71 @@ free_out:
 	per_cpu(threshold_banks, cpu)[bank] = NULL;
 }
 
-static void threshold_remove_device(unsigned int cpu)
+int mce_threshold_remove_device(unsigned int cpu)
 {
 	unsigned int bank;
 
+	if (!thresholding_en)
+		return 0;
+
 	for (bank = 0; bank < mca_cfg.banks; ++bank) {
 		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
 			continue;
 		threshold_remove_bank(cpu, bank);
 	}
 	kfree(per_cpu(threshold_banks, cpu));
+	per_cpu(threshold_banks, cpu) = NULL;
+	return 0;
 }
 
-/* get notified when a cpu comes on/off */
-static void
-amd_64_threshold_cpu_callback(unsigned long action, unsigned int cpu)
+/* create dir/files for all valid threshold banks */
+int mce_threshold_create_device(unsigned int cpu)
 {
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		threshold_create_device(cpu);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		threshold_remove_device(cpu);
-		break;
-	default:
-		break;
+	unsigned int bank;
+	struct threshold_bank **bp;
+	int err = 0;
+
+	if (!thresholding_en)
+		return 0;
+
+	bp = per_cpu(threshold_banks, cpu);
+	if (bp)
+		return 0;
+
+	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
+		     GFP_KERNEL);
+	if (!bp)
+		return -ENOMEM;
+
+	per_cpu(threshold_banks, cpu) = bp;
+
+	for (bank = 0; bank < mca_cfg.banks; ++bank) {
+		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
+			continue;
+		err = threshold_create_bank(cpu, bank);
+		if (err)
+			goto err;
 	}
+	return err;
+err:
+	mce_threshold_remove_device(cpu);
+	return err;
 }
 
 static __init int threshold_init_device(void)
 {
 	unsigned lcpu = 0;
 
+	if (mce_threshold_vector == amd_threshold_interrupt)
+		thresholding_en = true;
+
 	/* to hit CPUs online before the notifier is up */
 	for_each_online_cpu(lcpu) {
-		int err = threshold_create_device(lcpu);
+		int err = mce_threshold_create_device(lcpu);
 
 		if (err)
 			return err;
 	}
-	threshold_cpu_callback = amd_64_threshold_cpu_callback;
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 2f5c3418b18b..465aca8be009 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -270,58 +270,32 @@ static void thermal_throttle_remove_dev(struct device *dev)
 }
 
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-thermal_throttle_cpu_callback(struct notifier_block *nfb,
-			      unsigned long action,
-			      void *hcpu)
+static int thermal_throttle_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *dev;
-	int err = 0;
-
-	dev = get_cpu_device(cpu);
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		err = thermal_throttle_add_dev(dev, cpu);
-		WARN_ON(err);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		thermal_throttle_remove_dev(dev);
-		break;
-	}
-	return notifier_from_errno(err);
+	struct device *dev = get_cpu_device(cpu);
+
+	return thermal_throttle_add_dev(dev, cpu);
 }
 
-static struct notifier_block thermal_throttle_cpu_notifier =
+static int thermal_throttle_offline(unsigned int cpu)
 {
-	.notifier_call = thermal_throttle_cpu_callback,
-};
+	struct device *dev = get_cpu_device(cpu);
+
+	thermal_throttle_remove_dev(dev);
+	return 0;
+}
 
 static __init int thermal_throttle_init_device(void)
 {
-	unsigned int cpu = 0;
-	int err;
+	int ret;
 
 	if (!atomic_read(&therm_throt_en))
 		return 0;
 
-	cpu_notifier_register_begin();
-
-	/* connect live CPUs to sysfs */
-	for_each_online_cpu(cpu) {
-		err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
-		WARN_ON(err);
-	}
-
-	__register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
-	cpu_notifier_register_done();
-
-	return 0;
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/therm:online",
+				thermal_throttle_online,
+				thermal_throttle_offline);
+	return ret < 0 ? ret : 0;
 }
 device_initcall(thermal_throttle_init_device);
 
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 9095c80723d6..0931a105ffe1 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -45,6 +45,7 @@
 #include <asm/msr.h>
 
 static struct class *cpuid_class;
+static enum cpuhp_state cpuhp_cpuid_state;
 
 static void cpuid_smp_cpuid(void *cmd_block)
 {
@@ -111,7 +112,7 @@ static const struct file_operations cpuid_fops = {
 	.open = cpuid_open,
 };
 
-static int cpuid_device_create(int cpu)
+static int cpuid_device_create(unsigned int cpu)
 {
 	struct device *dev;
 
@@ -120,35 +121,12 @@ static int cpuid_device_create(int cpu)
 	return PTR_ERR_OR_ZERO(dev);
 }
 
-static void cpuid_device_destroy(int cpu)
+static int cpuid_device_destroy(unsigned int cpu)
 {
 	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
+	return 0;
 }
 
-static int cpuid_class_cpu_callback(struct notifier_block *nfb,
-				    unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	int err = 0;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-		err = cpuid_device_create(cpu);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-		cpuid_device_destroy(cpu);
-		break;
-	}
-	return notifier_from_errno(err);
-}
-
-static struct notifier_block cpuid_class_cpu_notifier =
-{
-	.notifier_call = cpuid_class_cpu_callback,
-};
-
 static char *cpuid_devnode(struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
@@ -156,15 +134,13 @@ static char *cpuid_devnode(struct device *dev, umode_t *mode)
 
 static int __init cpuid_init(void)
 {
-	int i, err = 0;
-	i = 0;
+	int err;
 
 	if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
 			      "cpu/cpuid", &cpuid_fops)) {
 		printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
 		       CPUID_MAJOR);
-		err = -EBUSY;
-		goto out;
+		return -EBUSY;
 	}
 	cpuid_class = class_create(THIS_MODULE, "cpuid");
 	if (IS_ERR(cpuid_class)) {
@@ -173,45 +149,28 @@ static int __init cpuid_init(void)
 	}
 	cpuid_class->devnode = cpuid_devnode;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i) {
-		err = cpuid_device_create(i);
-		if (err != 0)
-			goto out_class;
-	}
-	__register_hotcpu_notifier(&cpuid_class_cpu_notifier);
-	cpu_notifier_register_done();
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/cpuid:online",
+				cpuid_device_create, cpuid_device_destroy);
+	if (err < 0)
+		goto out_class;
 
-	err = 0;
-	goto out;
+	cpuhp_cpuid_state = err;
+	return 0;
 
 out_class:
-	i = 0;
-	for_each_online_cpu(i) {
-		cpuid_device_destroy(i);
-	}
-	cpu_notifier_register_done();
 	class_destroy(cpuid_class);
 out_chrdev:
 	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
-out:
 	return err;
 }
+module_init(cpuid_init);
 
 static void __exit cpuid_exit(void)
 {
-	int cpu = 0;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		cpuid_device_destroy(cpu);
+	cpuhp_remove_state(cpuhp_cpuid_state);
 	class_destroy(cpuid_class);
 	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
-	__unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
-	cpu_notifier_register_done();
 }
-
-module_init(cpuid_init);
 module_exit(cpuid_exit);
 
 MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 7f3550acde1b..f5e3ff835cc8 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -44,6 +44,7 @@
 #include <asm/msr.h>
 
 static struct class *msr_class;
+static enum cpuhp_state cpuhp_msr_state;
 
 static ssize_t msr_read(struct file *file, char __user *buf,
 			size_t count, loff_t *ppos)
@@ -180,7 +181,7 @@ static const struct file_operations msr_fops = {
 	.compat_ioctl = msr_ioctl,
 };
 
-static int msr_device_create(int cpu)
+static int msr_device_create(unsigned int cpu)
 {
 	struct device *dev;
 
@@ -189,34 +190,12 @@ static int msr_device_create(int cpu)
 	return PTR_ERR_OR_ZERO(dev);
 }
 
-static void msr_device_destroy(int cpu)
+static int msr_device_destroy(unsigned int cpu)
 {
 	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+	return 0;
 }
 
-static int msr_class_cpu_callback(struct notifier_block *nfb,
-				  unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	int err = 0;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-		err = msr_device_create(cpu);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-		msr_device_destroy(cpu);
-		break;
-	}
-	return notifier_from_errno(err);
-}
-
-static struct notifier_block __refdata msr_class_cpu_notifier = {
-	.notifier_call = msr_class_cpu_callback,
-};
-
 static char *msr_devnode(struct device *dev, umode_t *mode)
 {
 	return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt));
@@ -224,13 +203,11 @@ static char *msr_devnode(struct device *dev, umode_t *mode)
 
 static int __init msr_init(void)
 {
-	int i, err = 0;
-	i = 0;
+	int err;
 
 	if (__register_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr", &msr_fops)) {
 		pr_err("unable to get major %d for msr\n", MSR_MAJOR);
-		err = -EBUSY;
-		goto out;
+		return -EBUSY;
 	}
 	msr_class = class_create(THIS_MODULE, "msr");
 	if (IS_ERR(msr_class)) {
@@ -239,44 +216,28 @@ static int __init msr_init(void)
 	}
 	msr_class->devnode = msr_devnode;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i) {
-		err = msr_device_create(i);
-		if (err != 0)
-			goto out_class;
-	}
-	__register_hotcpu_notifier(&msr_class_cpu_notifier);
-	cpu_notifier_register_done();
-
-	err = 0;
-	goto out;
+	err  = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/msr:online",
+				 msr_device_create, msr_device_destroy);
+	if (err < 0)
+		goto out_class;
+	cpuhp_msr_state = err;
+	return 0;
 
 out_class:
-	i = 0;
-	for_each_online_cpu(i)
-		msr_device_destroy(i);
-	cpu_notifier_register_done();
+	cpuhp_remove_state(cpuhp_msr_state);
 	class_destroy(msr_class);
 out_chrdev:
 	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
-out:
 	return err;
 }
+module_init(msr_init);
 
 static void __exit msr_exit(void)
 {
-	int cpu = 0;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		msr_device_destroy(cpu);
+	cpuhp_remove_state(cpuhp_msr_state);
 	class_destroy(msr_class);
 	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
-	__unregister_hotcpu_notifier(&msr_class_cpu_notifier);
-	cpu_notifier_register_done();
 }
-
-module_init(msr_init);
 module_exit(msr_exit)
 
 MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 28c04123b6dd..ffdbc4836b4f 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -339,10 +339,11 @@ fail:
 	return 0;
 }
 
-static void nmi_cpu_setup(void *dummy)
+static void nmi_cpu_setup(void)
 {
 	int cpu = smp_processor_id();
 	struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
+
 	nmi_cpu_save_registers(msrs);
 	raw_spin_lock(&oprofilefs_lock);
 	model->setup_ctrs(model, msrs);
@@ -369,7 +370,7 @@ static void nmi_cpu_restore_registers(struct op_msrs *msrs)
 	}
 }
 
-static void nmi_cpu_shutdown(void *dummy)
+static void nmi_cpu_shutdown(void)
 {
 	unsigned int v;
 	int cpu = smp_processor_id();
@@ -387,20 +388,26 @@ static void nmi_cpu_shutdown(void *dummy)
 	nmi_cpu_restore_registers(msrs);
 }
 
-static void nmi_cpu_up(void *dummy)
+static int nmi_cpu_online(unsigned int cpu)
 {
+	local_irq_disable();
 	if (nmi_enabled)
-		nmi_cpu_setup(dummy);
+		nmi_cpu_setup();
 	if (ctr_running)
-		nmi_cpu_start(dummy);
+		nmi_cpu_start(NULL);
+	local_irq_enable();
+	return 0;
 }
 
-static void nmi_cpu_down(void *dummy)
+static int nmi_cpu_down_prep(unsigned int cpu)
 {
+	local_irq_disable();
 	if (ctr_running)
-		nmi_cpu_stop(dummy);
+		nmi_cpu_stop(NULL);
 	if (nmi_enabled)
-		nmi_cpu_shutdown(dummy);
+		nmi_cpu_shutdown();
+	local_irq_enable();
+	return 0;
 }
 
 static int nmi_create_files(struct dentry *root)
@@ -433,26 +440,7 @@ static int nmi_create_files(struct dentry *root)
 	return 0;
 }
 
-static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
-				 void *data)
-{
-	int cpu = (unsigned long)data;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DOWN_FAILED:
-	case CPU_ONLINE:
-		smp_call_function_single(cpu, nmi_cpu_up, NULL, 0);
-		break;
-	case CPU_DOWN_PREPARE:
-		smp_call_function_single(cpu, nmi_cpu_down, NULL, 1);
-		break;
-	}
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block oprofile_cpu_nb = {
-	.notifier_call = oprofile_cpu_notifier
-};
+static enum cpuhp_state cpuhp_nmi_online;
 
 static int nmi_setup(void)
 {
@@ -495,20 +483,17 @@ static int nmi_setup(void)
 	if (err)
 		goto fail;
 
-	cpu_notifier_register_begin();
-
-	/* Use get/put_online_cpus() to protect 'nmi_enabled' */
-	get_online_cpus();
 	nmi_enabled = 1;
 	/* make nmi_enabled visible to the nmi handler: */
 	smp_mb();
-	on_each_cpu(nmi_cpu_setup, NULL, 1);
-	__register_cpu_notifier(&oprofile_cpu_nb);
-	put_online_cpus();
-
-	cpu_notifier_register_done();
-
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/oprofile:online",
+				nmi_cpu_online, nmi_cpu_down_prep);
+	if (err < 0)
+		goto fail_nmi;
+	cpuhp_nmi_online = err;
 	return 0;
+fail_nmi:
+	unregister_nmi_handler(NMI_LOCAL, "oprofile");
 fail:
 	free_msrs();
 	return err;
@@ -518,17 +503,9 @@ static void nmi_shutdown(void)
 {
 	struct op_msrs *msrs;
 
-	cpu_notifier_register_begin();
-
-	/* Use get/put_online_cpus() to protect 'nmi_enabled' & 'ctr_running' */
-	get_online_cpus();
-	on_each_cpu(nmi_cpu_shutdown, NULL, 1);
+	cpuhp_remove_state(cpuhp_nmi_online);
 	nmi_enabled = 0;
 	ctr_running = 0;
-	__unregister_cpu_notifier(&oprofile_cpu_nb);
-	put_online_cpus();
-
-	cpu_notifier_register_done();
 
 	/* make variables visible to the nmi handler: */
 	smp_mb();
diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
index c20d2cc7ef64..ae387e5ee6f7 100644
--- a/arch/x86/pci/amd_bus.c
+++ b/arch/x86/pci/amd_bus.c
@@ -327,35 +327,18 @@ static int __init early_root_info_init(void)
 
 #define ENABLE_CF8_EXT_CFG      (1ULL << 46)
 
-static void enable_pci_io_ecs(void *unused)
+static int amd_bus_cpu_online(unsigned int cpu)
 {
 	u64 reg;
+
 	rdmsrl(MSR_AMD64_NB_CFG, reg);
 	if (!(reg & ENABLE_CF8_EXT_CFG)) {
 		reg |= ENABLE_CF8_EXT_CFG;
 		wrmsrl(MSR_AMD64_NB_CFG, reg);
 	}
+	return 0;
 }
 
-static int amd_cpu_notify(struct notifier_block *self, unsigned long action,
-			  void *hcpu)
-{
-	int cpu = (long)hcpu;
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		smp_call_function_single(cpu, enable_pci_io_ecs, NULL, 0);
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block amd_cpu_notifier = {
-	.notifier_call	= amd_cpu_notify,
-};
-
 static void __init pci_enable_pci_io_ecs(void)
 {
 #ifdef CONFIG_AMD_NB
@@ -385,7 +368,7 @@ static void __init pci_enable_pci_io_ecs(void)
 
 static int __init pci_io_ecs_init(void)
 {
-	int cpu;
+	int ret;
 
 	/* assume all cpus from fam10h have IO ECS */
 	if (boot_cpu_data.x86 < 0x10)
@@ -395,12 +378,9 @@ static int __init pci_io_ecs_init(void)
 	if (early_pci_allowed())
 		pci_enable_pci_io_ecs();
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		amd_cpu_notify(&amd_cpu_notifier, (unsigned long)CPU_ONLINE,
-			       (void *)(long)cpu);
-	__register_cpu_notifier(&amd_cpu_notifier);
-	cpu_notifier_register_done();
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/amd_bus:online",
+				amd_bus_cpu_online, NULL);
+	WARN_ON(ret < 0);
 
 	pci_probe |= PCI_HAS_IO_ECS;