diff --git a/arch/sparc64/kernel/ds.c b/arch/sparc64/kernel/ds.c
index b633171..1c58710 100644
--- a/arch/sparc64/kernel/ds.c
+++ b/arch/sparc64/kernel/ds.c
@@ -20,6 +20,7 @@
 #include <asm/power.h>
 #include <asm/mdesc.h>
 #include <asm/head.h>
+#include <asm/irq.h>
 
 #define DRV_MODULE_NAME		"ds"
 #define PFX DRV_MODULE_NAME	": "
@@ -559,6 +560,9 @@
 
 	kfree(resp);
 
+	/* Redistribute IRQs, taking into account the new cpus.  */
+	fixup_irqs();
+
 	return 0;
 }
 
@@ -566,7 +570,8 @@
 			      cpumask_t *mask)
 {
 	struct ds_data *resp;
-	int resp_len, ncpus;
+	int resp_len, ncpus, cpu;
+	unsigned long flags;
 
 	ncpus = cpus_weight(*mask);
 	resp_len = dr_cpu_size_response(ncpus);
@@ -578,9 +583,25 @@
 			     resp_len, ncpus, mask,
 			     DR_CPU_STAT_UNCONFIGURED);
 
+	for_each_cpu_mask(cpu, *mask) {
+		int err;
+
+		printk(KERN_INFO PFX "CPU[%d]: Shutting down cpu %d...\n",
+		       smp_processor_id(), cpu);
+		err = cpu_down(cpu);
+		if (err)
+			dr_cpu_mark(resp, cpu, ncpus,
+				    DR_CPU_RES_FAILURE,
+				    DR_CPU_STAT_CONFIGURED);
+	}
+
+	spin_lock_irqsave(&ds_lock, flags);
+	ds_send(ds_info->lp, resp, resp_len);
+	spin_unlock_irqrestore(&ds_lock, flags);
+
 	kfree(resp);
 
-	return -EOPNOTSUPP;
+	return 0;
 }
 
 static void process_dr_cpu_list(struct ds_cap_state *cp)
diff --git a/arch/sparc64/kernel/irq.c b/arch/sparc64/kernel/irq.c
index a1c916f..8cb3358 100644
--- a/arch/sparc64/kernel/irq.c
+++ b/arch/sparc64/kernel/irq.c
@@ -803,6 +803,26 @@
 	set_irq_regs(old_regs);
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+void fixup_irqs(void)
+{
+	unsigned int irq;
+
+	for (irq = 0; irq < NR_IRQS; irq++) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&irq_desc[irq].lock, flags);
+		if (irq_desc[irq].action &&
+		    !(irq_desc[irq].status & IRQ_PER_CPU)) {
+			if (irq_desc[irq].chip->set_affinity)
+				irq_desc[irq].chip->set_affinity(irq,
+					irq_desc[irq].affinity);
+		}
+		spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
+	}
+}
+#endif
+
 struct sun5_timer {
 	u64	count0;
 	u64	limit0;
diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index f5f97e2..9355750 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -29,6 +29,7 @@
 #include <linux/compat.h>
 #include <linux/tick.h>
 #include <linux/init.h>
+#include <linux/cpu.h>
 
 #include <asm/oplib.h>
 #include <asm/uaccess.h>
@@ -49,7 +50,7 @@
 
 /* #define VERBOSE_SHOWREGS */
 
-static void sparc64_yield(void)
+static void sparc64_yield(int cpu)
 {
 	if (tlb_type != hypervisor)
 		return;
@@ -57,7 +58,7 @@
 	clear_thread_flag(TIF_POLLING_NRFLAG);
 	smp_mb__after_clear_bit();
 
-	while (!need_resched()) {
+	while (!need_resched() && !cpu_is_offline(cpu)) {
 		unsigned long pstate;
 
 		/* Disable interrupts. */
@@ -68,7 +69,7 @@
 			: "=&r" (pstate)
 			: "i" (PSTATE_IE));
 
-		if (!need_resched())
+		if (!need_resched() && !cpu_is_offline(cpu))
 			sun4v_cpu_yield();
 
 		/* Re-enable interrupts. */
@@ -86,15 +87,25 @@
 /* The idle loop on sparc64. */
 void cpu_idle(void)
 {
+	int cpu = smp_processor_id();
+
 	set_thread_flag(TIF_POLLING_NRFLAG);
 
 	while(1) {
 		tick_nohz_stop_sched_tick();
-		while (!need_resched())
-			sparc64_yield();
+
+		while (!need_resched() && !cpu_is_offline(cpu))
+			sparc64_yield(cpu);
+
 		tick_nohz_restart_sched_tick();
 
 		preempt_enable_no_resched();
+
+#ifdef CONFIG_HOTPLUG_CPU
+		if (cpu_is_offline(cpu))
+			cpu_play_dead();
+#endif
+
 		schedule();
 		preempt_disable();
 	}
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index e038ae6..b448d33 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -44,6 +44,7 @@
 #include <asm/prom.h>
 #include <asm/mdesc.h>
 #include <asm/ldc.h>
+#include <asm/hypervisor.h>
 
 extern void calibrate_delay(void);
 
@@ -62,7 +63,6 @@
 EXPORT_SYMBOL(cpu_core_map);
 
 static cpumask_t smp_commenced_mask;
-static cpumask_t cpu_callout_map;
 
 void smp_info(struct seq_file *m)
 {
@@ -83,6 +83,8 @@
 			   i, cpu_data(i).clock_tick);
 }
 
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
+
 extern void setup_sparc64_timer(void);
 
 static volatile unsigned long callin_flag = 0;
@@ -121,7 +123,9 @@
 	while (!cpu_isset(cpuid, smp_commenced_mask))
 		rmb();
 
+	spin_lock(&call_lock);
 	cpu_set(cpuid, cpu_online_map);
+	spin_unlock(&call_lock);
 
 	/* idle thread is expected to have preempt disabled */
 	preempt_disable();
@@ -324,6 +328,9 @@
 	hv_err = sun4v_cpu_start(cpu, trampoline_ra,
 				 kimage_addr_to_ra(&sparc64_ttable_tl0),
 				 __pa(hdesc));
+	if (hv_err)
+		printk(KERN_ERR "ldom_startcpu_cpuid: sun4v_cpu_start() "
+		       "gives error %lu\n", hv_err);
 }
 #endif
 
@@ -350,7 +357,6 @@
 	p = fork_idle(cpu);
 	callin_flag = 0;
 	cpu_new_thread = task_thread_info(p);
-	cpu_set(cpu, cpu_callout_map);
 
 	if (tlb_type == hypervisor) {
 		/* Alloc the mondo queues, cpu will load them.  */
@@ -379,7 +385,6 @@
 		ret = 0;
 	} else {
 		printk("Processor %d is stuck.\n", cpu);
-		cpu_clear(cpu, cpu_callout_map);
 		ret = -ENODEV;
 	}
 	cpu_new_thread = NULL;
@@ -791,7 +796,6 @@
 	int wait;
 };
 
-static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
 static struct call_data_struct *call_data;
 
 extern unsigned long xcall_call_function;
@@ -1241,7 +1245,7 @@
 {
 	unsigned int i;
 
-	for_each_possible_cpu(i) {
+	for_each_present_cpu(i) {
 		unsigned int j;
 
 		cpus_clear(cpu_core_map[i]);
@@ -1250,14 +1254,14 @@
 			continue;
 		}
 
-		for_each_possible_cpu(j) {
+		for_each_present_cpu(j) {
 			if (cpu_data(i).core_id ==
 			    cpu_data(j).core_id)
 				cpu_set(j, cpu_core_map[i]);
 		}
 	}
 
-	for_each_possible_cpu(i) {
+	for_each_present_cpu(i) {
 		unsigned int j;
 
 		cpus_clear(cpu_sibling_map[i]);
@@ -1266,7 +1270,7 @@
 			continue;
 		}
 
-		for_each_possible_cpu(j) {
+		for_each_present_cpu(j) {
 			if (cpu_data(i).proc_id ==
 			    cpu_data(j).proc_id)
 				cpu_set(j, cpu_sibling_map[i]);
@@ -1296,16 +1300,106 @@
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+void cpu_play_dead(void)
+{
+	int cpu = smp_processor_id();
+	unsigned long pstate;
+
+	idle_task_exit();
+
+	if (tlb_type == hypervisor) {
+		struct trap_per_cpu *tb = &trap_block[cpu];
+
+		sun4v_cpu_qconf(HV_CPU_QUEUE_CPU_MONDO,
+				tb->cpu_mondo_pa, 0);
+		sun4v_cpu_qconf(HV_CPU_QUEUE_DEVICE_MONDO,
+				tb->dev_mondo_pa, 0);
+		sun4v_cpu_qconf(HV_CPU_QUEUE_RES_ERROR,
+				tb->resum_mondo_pa, 0);
+		sun4v_cpu_qconf(HV_CPU_QUEUE_NONRES_ERROR,
+				tb->nonresum_mondo_pa, 0);
+	}
+
+	cpu_clear(cpu, smp_commenced_mask);
+	membar_safe("#Sync");
+
+	local_irq_disable();
+
+	__asm__ __volatile__(
+		"rdpr	%%pstate, %0\n\t"
+		"wrpr	%0, %1, %%pstate"
+		: "=r" (pstate)
+		: "i" (PSTATE_IE));
+
+	while (1)
+		barrier();
+}
+
 int __cpu_disable(void)
 {
-	printk(KERN_ERR "SMP: __cpu_disable() on cpu %d\n",
-	       smp_processor_id());
-	return -ENODEV;
+	int cpu = smp_processor_id();
+	cpuinfo_sparc *c;
+	int i;
+
+	for_each_cpu_mask(i, cpu_core_map[cpu])
+		cpu_clear(cpu, cpu_core_map[i]);
+	cpus_clear(cpu_core_map[cpu]);
+
+	for_each_cpu_mask(i, cpu_sibling_map[cpu])
+		cpu_clear(cpu, cpu_sibling_map[i]);
+	cpus_clear(cpu_sibling_map[cpu]);
+
+	c = &cpu_data(cpu);
+
+	c->core_id = 0;
+	c->proc_id = -1;
+
+	spin_lock(&call_lock);
+	cpu_clear(cpu, cpu_online_map);
+	spin_unlock(&call_lock);
+
+	smp_wmb();
+
+	/* Make sure no interrupts point to this cpu.  */
+	fixup_irqs();
+
+	local_irq_enable();
+	mdelay(1);
+	local_irq_disable();
+
+	return 0;
 }
 
 void __cpu_die(unsigned int cpu)
 {
-	printk(KERN_ERR "SMP: __cpu_die(%u)\n", cpu);
+	int i;
+
+	for (i = 0; i < 100; i++) {
+		smp_rmb();
+		if (!cpu_isset(cpu, smp_commenced_mask))
+			break;
+		msleep(100);
+	}
+	if (cpu_isset(cpu, smp_commenced_mask)) {
+		printk(KERN_ERR "CPU %u didn't die...\n", cpu);
+	} else {
+#if defined(CONFIG_SUN_LDOMS)
+		unsigned long hv_err;
+		int limit = 100;
+
+		do {
+			hv_err = sun4v_cpu_stop(cpu);
+			if (hv_err == HV_EOK) {
+				cpu_clear(cpu, cpu_present_map);
+				break;
+			}
+		} while (--limit > 0);
+		if (limit <= 0) {
+			printk(KERN_ERR "sun4v_cpu_stop() fails err=%lu\n",
+			       hv_err);
+		}
+#endif
+	}
 }
 #endif