Initial import

1 files changed, 1514 insertions, 0 deletions

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
new file mode 100644
index 000000000..50e547eac
--- /dev/null
+++ b/arch/x86/kernel/smpboot.c
@@ -0,0 +1,1514 @@
+ /*
+ *	x86 SMP booting functions
+ *
+ *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
+ *	(c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
+ *	Copyright 2001 Andi Kleen, SuSE Labs.
+ *
+ *	Much of the core SMP work is based on previous work by Thomas Radke, to
+ *	whom a great many thanks are extended.
+ *
+ *	Thanks to Intel for making available several different Pentium,
+ *	Pentium Pro and Pentium-II/Xeon MP machines.
+ *	Original development of Linux SMP code supported by Caldera.
+ *
+ *	This code is released under the GNU General Public License version 2 or
+ *	later.
+ *
+ *	Fixes
+ *		Felix Koop	:	NR_CPUS used properly
+ *		Jose Renau	:	Handle single CPU case.
+ *		Alan Cox	:	By repeated request 8) - Total BogoMIPS report.
+ *		Greg Wright	:	Fix for kernel stacks panic.
+ *		Erich Boleyn	:	MP v1.4 and additional changes.
+ *	Matthias Sattler	:	Changes for 2.1 kernel map.
+ *	Michel Lespinasse	:	Changes for 2.1 kernel map.
+ *	Michael Chastain	:	Change trampoline.S to gnu as.
+ *		Alan Cox	:	Dumb bug: 'B' step PPro's are fine
+ *		Ingo Molnar	:	Added APIC timers, based on code
+ *					from Jose Renau
+ *		Ingo Molnar	:	various cleanups and rewrites
+ *		Tigran Aivazian	:	fixed "0.00 in /proc/uptime on SMP" bug.
+ *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs
+ *	Andi Kleen		:	Changed for SMP boot into long mode.
+ *		Martin J. Bligh	: 	Added support for multi-quad systems
+ *		Dave Jones	:	Report invalid combinations of Athlon CPUs.
+ *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process.
+ *      Andi Kleen              :       Converted to new state machine.
+ *	Ashok Raj		: 	CPU hotplug support
+ *	Glauber Costa		:	i386 and x86_64 integration
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/percpu.h>
+#include <linux/bootmem.h>
+#include <linux/err.h>
+#include <linux/nmi.h>
+#include <linux/tboot.h>
+#include <linux/stackprotector.h>
+#include <linux/gfp.h>
+#include <linux/cpuidle.h>
+
+#include <asm/acpi.h>
+#include <asm/desc.h>
+#include <asm/nmi.h>
+#include <asm/irq.h>
+#include <asm/idle.h>
+#include <asm/realmode.h>
+#include <asm/cpu.h>
+#include <asm/numa.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/mtrr.h>
+#include <asm/mwait.h>
+#include <asm/apic.h>
+#include <asm/io_apic.h>
+#include <asm/i387.h>
+#include <asm/fpu-internal.h>
+#include <asm/setup.h>
+#include <asm/uv/uv.h>
+#include <linux/mc146818rtc.h>
+#include <asm/i8259.h>
+#include <asm/realmode.h>
+#include <asm/misc.h>
+
+/* Number of siblings per CPU package */
+int smp_num_siblings = 1;
+EXPORT_SYMBOL(smp_num_siblings);
+
+/* Last level cache ID of each logical CPU */
+DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID;
+
+/* representing HT siblings of each logical CPU */
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
+EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
+
+/* representing HT and core siblings of each logical CPU */
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
+EXPORT_PER_CPU_SYMBOL(cpu_core_map);
+
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
+
+/* Per CPU bogomips and other parameters */
+DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
+EXPORT_PER_CPU_SYMBOL(cpu_info);
+
+atomic_t init_deasserted;
+
+static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc_lock, flags);
+	CMOS_WRITE(0xa, 0xf);
+	spin_unlock_irqrestore(&rtc_lock, flags);
+	local_flush_tlb();
+	pr_debug("1.\n");
+	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
+							start_eip >> 4;
+	pr_debug("2.\n");
+	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
+							start_eip & 0xf;
+	pr_debug("3.\n");
+}
+
+static inline void smpboot_restore_warm_reset_vector(void)
+{
+	unsigned long flags;
+
+	/*
+	 * Install writable page 0 entry to set BIOS data area.
+	 */
+	local_flush_tlb();
+
+	/*
+	 * Paranoid:  Set warm reset code and vector here back
+	 * to default values.
+	 */
+	spin_lock_irqsave(&rtc_lock, flags);
+	CMOS_WRITE(0, 0xf);
+	spin_unlock_irqrestore(&rtc_lock, flags);
+
+	*((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0;
+}
+
+/*
+ * Report back to the Boot Processor during boot time or to the caller processor
+ * during CPU online.
+ */
+static void smp_callin(void)
+{
+	int cpuid, phys_id;
+
+	/*
+	 * If waken up by an INIT in an 82489DX configuration
+	 * we may get here before an INIT-deassert IPI reaches
+	 * our local APIC.  We have to wait for the IPI or we'll
+	 * lock up on an APIC access.
+	 *
+	 * Since CPU0 is not wakened up by INIT, it doesn't wait for the IPI.
+	 */
+	cpuid = smp_processor_id();
+	if (apic->wait_for_init_deassert && cpuid)
+		while (!atomic_read(&init_deasserted))
+			cpu_relax();
+
+	/*
+	 * (This works even if the APIC is not enabled.)
+	 */
+	phys_id = read_apic_id();
+
+	/*
+	 * the boot CPU has finished the init stage and is spinning
+	 * on callin_map until we finish. We are free to set up this
+	 * CPU, first the APIC. (this is probably redundant on most
+	 * boards)
+	 */
+	apic_ap_setup();
+
+	/*
+	 * Need to setup vector mappings before we enable interrupts.
+	 */
+	setup_vector_irq(smp_processor_id());
+
+	/*
+	 * Save our processor parameters. Note: this information
+	 * is needed for clock calibration.
+	 */
+	smp_store_cpu_info(cpuid);
+
+	/*
+	 * Get our bogomips.
+	 * Update loops_per_jiffy in cpu_data. Previous call to
+	 * smp_store_cpu_info() stored a value that is close but not as
+	 * accurate as the value just calculated.
+	 */
+	calibrate_delay();
+	cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
+	pr_debug("Stack at about %p\n", &cpuid);
+
+	/*
+	 * This must be done before setting cpu_online_mask
+	 * or calling notify_cpu_starting.
+	 */
+	set_cpu_sibling_map(raw_smp_processor_id());
+	wmb();
+
+	notify_cpu_starting(cpuid);
+
+	/*
+	 * Allow the master to continue.
+	 */
+	cpumask_set_cpu(cpuid, cpu_callin_mask);
+}
+
+static int cpu0_logical_apicid;
+static int enable_start_cpu0;
+/*
+ * Activate a secondary processor.
+ */
+static void notrace start_secondary(void *unused)
+{
+	/*
+	 * Don't put *anything* before cpu_init(), SMP booting is too
+	 * fragile that we want to limit the things done here to the
+	 * most necessary things.
+	 */
+	cpu_init();
+	x86_cpuinit.early_percpu_clock_init();
+	preempt_disable();
+	smp_callin();
+
+	enable_start_cpu0 = 0;
+
+#ifdef CONFIG_X86_32
+	/* switch away from the initial page table */
+	load_cr3(swapper_pg_dir);
+	__flush_tlb_all();
+#endif
+
+	/* otherwise gcc will move up smp_processor_id before the cpu_init */
+	barrier();
+	/*
+	 * Check TSC synchronization with the BP:
+	 */
+	check_tsc_sync_target();
+
+	/*
+	 * Enable the espfix hack for this CPU
+	 */
+#ifdef CONFIG_X86_ESPFIX64
+	init_espfix_ap();
+#endif
+
+	/*
+	 * We need to hold vector_lock so there the set of online cpus
+	 * does not change while we are assigning vectors to cpus.  Holding
+	 * this lock ensures we don't half assign or remove an irq from a cpu.
+	 */
+	lock_vector_lock();
+	set_cpu_online(smp_processor_id(), true);
+	unlock_vector_lock();
+	cpu_set_state_online(smp_processor_id());
+	x86_platform.nmi_init();
+
+	/* enable local interrupts */
+	local_irq_enable();
+
+	/* to prevent fake stack check failure in clock setup */
+	boot_init_stack_canary();
+
+	x86_cpuinit.setup_percpu_clockev();
+
+	wmb();
+	cpu_startup_entry(CPUHP_ONLINE);
+}
+
+void __init smp_store_boot_cpu_info(void)
+{
+	int id = 0; /* CPU 0 */
+	struct cpuinfo_x86 *c = &cpu_data(id);
+
+	*c = boot_cpu_data;
+	c->cpu_index = id;
+}
+
+/*
+ * The bootstrap kernel entry code has set these up. Save them for
+ * a given CPU
+ */
+void smp_store_cpu_info(int id)
+{
+	struct cpuinfo_x86 *c = &cpu_data(id);
+
+	*c = boot_cpu_data;
+	c->cpu_index = id;
+	/*
+	 * During boot time, CPU0 has this setup already. Save the info when
+	 * bringing up AP or offlined CPU0.
+	 */
+	identify_secondary_cpu(c);
+}
+
+static bool
+topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+
+	return (cpu_to_node(cpu1) == cpu_to_node(cpu2));
+}
+
+static bool
+topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
+{
+	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+
+	return !WARN_ONCE(!topology_same_node(c, o),
+		"sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
+		"[node: %d != %d]. Ignoring dependency.\n",
+		cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
+}
+
+#define link_mask(_m, c1, c2)						\
+do {									\
+	cpumask_set_cpu((c1), cpu_##_m##_mask(c2));			\
+	cpumask_set_cpu((c2), cpu_##_m##_mask(c1));			\
+} while (0)
+
+static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	if (cpu_has_topoext) {
+		int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+
+		if (c->phys_proc_id == o->phys_proc_id &&
+		    per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2) &&
+		    c->compute_unit_id == o->compute_unit_id)
+			return topology_sane(c, o, "smt");
+
+	} else if (c->phys_proc_id == o->phys_proc_id &&
+		   c->cpu_core_id == o->cpu_core_id) {
+		return topology_sane(c, o, "smt");
+	}
+
+	return false;
+}
+
+static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+
+	if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID &&
+	    per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2))
+		return topology_sane(c, o, "llc");
+
+	return false;
+}
+
+/*
+ * Unlike the other levels, we do not enforce keeping a
+ * multicore group inside a NUMA node.  If this happens, we will
+ * discard the MC level of the topology later.
+ */
+static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+{
+	if (c->phys_proc_id == o->phys_proc_id)
+		return true;
+	return false;
+}
+
+static struct sched_domain_topology_level numa_inside_package_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+#ifdef CONFIG_SCHED_MC
+	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+#endif
+	{ NULL, },
+};
+/*
+ * set_sched_topology() sets the topology internal to a CPU.  The
+ * NUMA topologies are layered on top of it to build the full
+ * system topology.
+ *
+ * If NUMA nodes are observed to occur within a CPU package, this
+ * function should be called.  It forces the sched domain code to
+ * only use the SMT level for the CPU portion of the topology.
+ * This essentially falls back to relying on NUMA information
+ * from the SRAT table to describe the entire system topology
+ * (except for hyperthreads).
+ */
+static void primarily_use_numa_for_topology(void)
+{
+	set_sched_topology(numa_inside_package_topology);
+}
+
+void set_cpu_sibling_map(int cpu)
+{
+	bool has_smt = smp_num_siblings > 1;
+	bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
+	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	struct cpuinfo_x86 *o;
+	int i;
+
+	cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
+
+	if (!has_mp) {
+		cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
+		cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
+		cpumask_set_cpu(cpu, cpu_core_mask(cpu));
+		c->booted_cores = 1;
+		return;
+	}
+
+	for_each_cpu(i, cpu_sibling_setup_mask) {
+		o = &cpu_data(i);
+
+		if ((i == cpu) || (has_smt && match_smt(c, o)))
+			link_mask(sibling, cpu, i);
+
+		if ((i == cpu) || (has_mp && match_llc(c, o)))
+			link_mask(llc_shared, cpu, i);
+
+	}
+
+	/*
+	 * This needs a separate iteration over the cpus because we rely on all
+	 * cpu_sibling_mask links to be set-up.
+	 */
+	for_each_cpu(i, cpu_sibling_setup_mask) {
+		o = &cpu_data(i);
+
+		if ((i == cpu) || (has_mp && match_die(c, o))) {
+			link_mask(core, cpu, i);
+
+			/*
+			 *  Does this new cpu bringup a new core?
+			 */
+			if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) {
+				/*
+				 * for each core in package, increment
+				 * the booted_cores for this new cpu
+				 */
+				if (cpumask_first(cpu_sibling_mask(i)) == i)
+					c->booted_cores++;
+				/*
+				 * increment the core count for all
+				 * the other cpus in this package
+				 */
+				if (i != cpu)
+					cpu_data(i).booted_cores++;
+			} else if (i != cpu && !c->booted_cores)
+				c->booted_cores = cpu_data(i).booted_cores;
+		}
+		if (match_die(c, o) && !topology_same_node(c, o))
+			primarily_use_numa_for_topology();
+	}
+}
+
+/* maps the cpu to the sched domain representing multi-core */
+const struct cpumask *cpu_coregroup_mask(int cpu)
+{
+	return cpu_llc_shared_mask(cpu);
+}
+
+static void impress_friends(void)
+{
+	int cpu;
+	unsigned long bogosum = 0;
+	/*
+	 * Allow the user to impress friends.
+	 */
+	pr_debug("Before bogomips\n");
+	for_each_possible_cpu(cpu)
+		if (cpumask_test_cpu(cpu, cpu_callout_mask))
+			bogosum += cpu_data(cpu).loops_per_jiffy;
+	pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
+		num_online_cpus(),
+		bogosum/(500000/HZ),
+		(bogosum/(5000/HZ))%100);
+
+	pr_debug("Before bogocount - setting activated=1\n");
+}
+
+void __inquire_remote_apic(int apicid)
+{
+	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
+	const char * const names[] = { "ID", "VERSION", "SPIV" };
+	int timeout;
+	u32 status;
+
+	pr_info("Inquiring remote APIC 0x%x...\n", apicid);
+
+	for (i = 0; i < ARRAY_SIZE(regs); i++) {
+		pr_info("... APIC 0x%x %s: ", apicid, names[i]);
+
+		/*
+		 * Wait for idle.
+		 */
+		status = safe_apic_wait_icr_idle();
+		if (status)
+			pr_cont("a previous APIC delivery may have failed\n");
+
+		apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
+
+		timeout = 0;
+		do {
+			udelay(100);
+			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
+		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
+
+		switch (status) {
+		case APIC_ICR_RR_VALID:
+			status = apic_read(APIC_RRR);
+			pr_cont("%08x\n", status);
+			break;
+		default:
+			pr_cont("failed\n");
+		}
+	}
+}
+
+/*
+ * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
+ * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
+ * won't ... remember to clear down the APIC, etc later.
+ */
+int
+wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
+{
+	unsigned long send_status, accept_status = 0;
+	int maxlvt;
+
+	/* Target chip */
+	/* Boot on the stack */
+	/* Kick the second */
+	apic_icr_write(APIC_DM_NMI | apic->dest_logical, apicid);
+
+	pr_debug("Waiting for send to finish...\n");
+	send_status = safe_apic_wait_icr_idle();
+
+	/*
+	 * Give the other CPU some time to accept the IPI.
+	 */
+	udelay(200);
+	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
+		maxlvt = lapic_get_maxlvt();
+		if (maxlvt > 3)			/* Due to the Pentium erratum 3AP.  */
+			apic_write(APIC_ESR, 0);
+		accept_status = (apic_read(APIC_ESR) & 0xEF);
+	}
+	pr_debug("NMI sent\n");
+
+	if (send_status)
+		pr_err("APIC never delivered???\n");
+	if (accept_status)
+		pr_err("APIC delivery error (%lx)\n", accept_status);
+
+	return (send_status | accept_status);
+}
+
+static int
+wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
+{
+	unsigned long send_status, accept_status = 0;
+	int maxlvt, num_starts, j;
+
+	maxlvt = lapic_get_maxlvt();
+
+	/*
+	 * Be paranoid about clearing APIC errors.
+	 */
+	if (APIC_INTEGRATED(apic_version[phys_apicid])) {
+		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
+			apic_write(APIC_ESR, 0);
+		apic_read(APIC_ESR);
+	}
+
+	pr_debug("Asserting INIT\n");
+
+	/*
+	 * Turn INIT on target chip
+	 */
+	/*
+	 * Send IPI
+	 */
+	apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
+		       phys_apicid);
+
+	pr_debug("Waiting for send to finish...\n");
+	send_status = safe_apic_wait_icr_idle();
+
+	mdelay(10);
+
+	pr_debug("Deasserting INIT\n");
+
+	/* Target chip */
+	/* Send IPI */
+	apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
+
+	pr_debug("Waiting for send to finish...\n");
+	send_status = safe_apic_wait_icr_idle();
+
+	mb();
+	atomic_set(&init_deasserted, 1);
+
+	/*
+	 * Should we send STARTUP IPIs ?
+	 *
+	 * Determine this based on the APIC version.
+	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
+	 */
+	if (APIC_INTEGRATED(apic_version[phys_apicid]))
+		num_starts = 2;
+	else
+		num_starts = 0;
+
+	/*
+	 * Paravirt / VMI wants a startup IPI hook here to set up the
+	 * target processor state.
+	 */
+	startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
+			 stack_start);
+
+	/*
+	 * Run STARTUP IPI loop.
+	 */
+	pr_debug("#startup loops: %d\n", num_starts);
+
+	for (j = 1; j <= num_starts; j++) {
+		pr_debug("Sending STARTUP #%d\n", j);
+		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
+			apic_write(APIC_ESR, 0);
+		apic_read(APIC_ESR);
+		pr_debug("After apic_write\n");
+
+		/*
+		 * STARTUP IPI
+		 */
+
+		/* Target chip */
+		/* Boot on the stack */
+		/* Kick the second */
+		apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
+			       phys_apicid);
+
+		/*
+		 * Give the other CPU some time to accept the IPI.
+		 */
+		udelay(300);
+
+		pr_debug("Startup point 1\n");
+
+		pr_debug("Waiting for send to finish...\n");
+		send_status = safe_apic_wait_icr_idle();
+
+		/*
+		 * Give the other CPU some time to accept the IPI.
+		 */
+		udelay(200);
+		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
+			apic_write(APIC_ESR, 0);
+		accept_status = (apic_read(APIC_ESR) & 0xEF);
+		if (send_status || accept_status)
+			break;
+	}
+	pr_debug("After Startup\n");
+
+	if (send_status)
+		pr_err("APIC never delivered???\n");
+	if (accept_status)
+		pr_err("APIC delivery error (%lx)\n", accept_status);
+
+	return (send_status | accept_status);
+}
+
+void smp_announce(void)
+{
+	int num_nodes = num_online_nodes();
+
+	printk(KERN_INFO "x86: Booted up %d node%s, %d CPUs\n",
+	       num_nodes, (num_nodes > 1 ? "s" : ""), num_online_cpus());
+}
+
+/* reduce the number of lines printed when booting a large cpu count system */
+static void announce_cpu(int cpu, int apicid)
+{
+	static int current_node = -1;
+	int node = early_cpu_to_node(cpu);
+	static int width, node_width;
+
+	if (!width)
+		width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
+
+	if (!node_width)
+		node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */
+
+	if (cpu == 1)
+		printk(KERN_INFO "x86: Booting SMP configuration:\n");
+
+	if (system_state == SYSTEM_BOOTING) {
+		if (node != current_node) {
+			if (current_node > (-1))
+				pr_cont("\n");
+			current_node = node;
+
+			printk(KERN_INFO ".... node %*s#%d, CPUs:  ",
+			       node_width - num_digits(node), " ", node);
+		}
+
+		/* Add padding for the BSP */
+		if (cpu == 1)
+			pr_cont("%*s", width + 1, " ");
+
+		pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
+
+	} else
+		pr_info("Booting Node %d Processor %d APIC 0x%x\n",
+			node, cpu, apicid);
+}
+
+static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
+{
+	int cpu;
+
+	cpu = smp_processor_id();
+	if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0)
+		return NMI_HANDLED;
+
+	return NMI_DONE;
+}
+
+/*
+ * Wake up AP by INIT, INIT, STARTUP sequence.
+ *
+ * Instead of waiting for STARTUP after INITs, BSP will execute the BIOS
+ * boot-strap code which is not a desired behavior for waking up BSP. To
+ * void the boot-strap code, wake up CPU0 by NMI instead.
+ *
+ * This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined
+ * (i.e. physically hot removed and then hot added), NMI won't wake it up.
+ * We'll change this code in the future to wake up hard offlined CPU0 if
+ * real platform and request are available.
+ */
+static int
+wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
+	       int *cpu0_nmi_registered)
+{
+	int id;
+	int boot_error;
+
+	preempt_disable();
+
+	/*
+	 * Wake up AP by INIT, INIT, STARTUP sequence.
+	 */
+	if (cpu) {
+		boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+		goto out;
+	}
+
+	/*
+	 * Wake up BSP by nmi.
+	 *
+	 * Register a NMI handler to help wake up CPU0.
+	 */
+	boot_error = register_nmi_handler(NMI_LOCAL,
+					  wakeup_cpu0_nmi, 0, "wake_cpu0");
+
+	if (!boot_error) {
+		enable_start_cpu0 = 1;
+		*cpu0_nmi_registered = 1;
+		if (apic->dest_logical == APIC_DEST_LOGICAL)
+			id = cpu0_logical_apicid;
+		else
+			id = apicid;
+		boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip);
+	}
+
+out:
+	preempt_enable();
+
+	return boot_error;
+}
+
+void common_cpu_up(unsigned int cpu, struct task_struct *idle)
+{
+	/* Just in case we booted with a single CPU. */
+	alternatives_enable_smp();
+
+	per_cpu(current_task, cpu) = idle;
+
+#ifdef CONFIG_X86_32
+	/* Stack for startup_32 can be just as for start_secondary onwards */
+	irq_ctx_init(cpu);
+	per_cpu(cpu_current_top_of_stack, cpu) =
+		(unsigned long)task_stack_page(idle) + THREAD_SIZE;
+#else
+	clear_tsk_thread_flag(idle, TIF_FORK);
+	initial_gs = per_cpu_offset(cpu);
+#endif
+	per_cpu(kernel_stack, cpu) =
+		(unsigned long)task_stack_page(idle) + THREAD_SIZE;
+}
+
+/*
+ * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
+ * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
+ * Returns zero if CPU booted OK, else error code from
+ * ->wakeup_secondary_cpu.
+ */
+static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
+{
+	volatile u32 *trampoline_status =
+		(volatile u32 *) __va(real_mode_header->trampoline_status);
+	/* start_ip had better be page-aligned! */
+	unsigned long start_ip = real_mode_header->trampoline_start;
+
+	unsigned long boot_error = 0;
+	int cpu0_nmi_registered = 0;
+	unsigned long timeout;
+
+	idle->thread.sp = (unsigned long) (((struct pt_regs *)
+			  (THREAD_SIZE +  task_stack_page(idle))) - 1);
+
+	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
+	initial_code = (unsigned long)start_secondary;
+	stack_start  = idle->thread.sp;
+
+	/* So we see what's up */
+	announce_cpu(cpu, apicid);
+
+	/*
+	 * This grunge runs the startup process for
+	 * the targeted processor.
+	 */
+
+	atomic_set(&init_deasserted, 0);
+
+	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
+
+		pr_debug("Setting warm reset code and vector.\n");
+
+		smpboot_setup_warm_reset_vector(start_ip);
+		/*
+		 * Be paranoid about clearing APIC errors.
+		*/
+		if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
+			apic_write(APIC_ESR, 0);
+			apic_read(APIC_ESR);
+		}
+	}
+
+	/*
+	 * AP might wait on cpu_callout_mask in cpu_init() with
+	 * cpu_initialized_mask set if previous attempt to online
+	 * it timed-out. Clear cpu_initialized_mask so that after
+	 * INIT/SIPI it could start with a clean state.
+	 */
+	cpumask_clear_cpu(cpu, cpu_initialized_mask);
+	smp_mb();
+
+	/*
+	 * Wake up a CPU in difference cases:
+	 * - Use the method in the APIC driver if it's defined
+	 * Otherwise,
+	 * - Use an INIT boot APIC message for APs or NMI for BSP.
+	 */
+	if (apic->wakeup_secondary_cpu)
+		boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
+	else
+		boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid,
+						     &cpu0_nmi_registered);
+
+	if (!boot_error) {
+		/*
+		 * Wait 10s total for a response from AP
+		 */
+		boot_error = -1;
+		timeout = jiffies + 10*HZ;
+		while (time_before(jiffies, timeout)) {
+			if (cpumask_test_cpu(cpu, cpu_initialized_mask)) {
+				/*
+				 * Tell AP to proceed with initialization
+				 */
+				cpumask_set_cpu(cpu, cpu_callout_mask);
+				boot_error = 0;
+				break;
+			}
+			udelay(100);
+			schedule();
+		}
+	}
+
+	if (!boot_error) {
+		/*
+		 * Wait till AP completes initial initialization
+		 */
+		while (!cpumask_test_cpu(cpu, cpu_callin_mask)) {
+			/*
+			 * Allow other tasks to run while we wait for the
+			 * AP to come online. This also gives a chance
+			 * for the MTRR work(triggered by the AP coming online)
+			 * to be completed in the stop machine context.
+			 */
+			udelay(100);
+			schedule();
+		}
+	}
+
+	/* mark "stuck" area as not stuck */
+	*trampoline_status = 0;
+
+	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
+		/*
+		 * Cleanup possible dangling ends...
+		 */
+		smpboot_restore_warm_reset_vector();
+	}
+	/*
+	 * Clean up the nmi handler. Do this after the callin and callout sync
+	 * to avoid impact of possible long unregister time.
+	 */
+	if (cpu0_nmi_registered)
+		unregister_nmi_handler(NMI_LOCAL, "wake_cpu0");
+
+	return boot_error;
+}
+
+int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
+{
+	int apicid = apic->cpu_present_to_apicid(cpu);
+	unsigned long flags;
+	int err;
+
+	WARN_ON(irqs_disabled());
+
+	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
+
+	if (apicid == BAD_APICID ||
+	    !physid_isset(apicid, phys_cpu_present_map) ||
+	    !apic->apic_id_valid(apicid)) {
+		pr_err("%s: bad cpu %d\n", __func__, cpu);
+		return -EINVAL;
+	}
+
+	/*
+	 * Already booted CPU?
+	 */
+	if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
+		pr_debug("do_boot_cpu %d Already started\n", cpu);
+		return -ENOSYS;
+	}
+
+	/*
+	 * Save current MTRR state in case it was changed since early boot
+	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
+	 */
+	mtrr_save_state();
+
+	/* x86 CPUs take themselves offline, so delayed offline is OK. */
+	err = cpu_check_up_prepare(cpu);
+	if (err && err != -EBUSY)
+		return err;
+
+	/* the FPU context is blank, nobody can own it */
+	__cpu_disable_lazy_restore(cpu);
+
+	common_cpu_up(cpu, tidle);
+
+	err = do_boot_cpu(apicid, cpu, tidle);
+	if (err) {
+		pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
+		return -EIO;
+	}
+
+	/*
+	 * Check TSC synchronization with the AP (keep irqs disabled
+	 * while doing so):
+	 */
+	local_irq_save(flags);
+	check_tsc_sync_source(cpu);
+	local_irq_restore(flags);
+
+	while (!cpu_online(cpu)) {
+		cpu_relax();
+		touch_nmi_watchdog();
+	}
+
+	return 0;
+}
+
+/**
+ * arch_disable_smp_support() - disables SMP support for x86 at runtime
+ */
+void arch_disable_smp_support(void)
+{
+	disable_ioapic_support();
+}
+
+/*
+ * Fall back to non SMP mode after errors.
+ *
+ * RED-PEN audit/test this more. I bet there is more state messed up here.
+ */
+static __init void disable_smp(void)
+{
+	pr_info("SMP disabled\n");
+
+	disable_ioapic_support();
+
+	init_cpu_present(cpumask_of(0));
+	init_cpu_possible(cpumask_of(0));
+
+	if (smp_found_config)
+		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
+	else
+		physid_set_mask_of_physid(0, &phys_cpu_present_map);
+	cpumask_set_cpu(0, cpu_sibling_mask(0));
+	cpumask_set_cpu(0, cpu_core_mask(0));
+}
+
+enum {
+	SMP_OK,
+	SMP_NO_CONFIG,
+	SMP_NO_APIC,
+	SMP_FORCE_UP,
+};
+
+/*
+ * Various sanity checks.
+ */
+static int __init smp_sanity_check(unsigned max_cpus)
+{
+	preempt_disable();
+
+#if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
+	if (def_to_bigsmp && nr_cpu_ids > 8) {
+		unsigned int cpu;
+		unsigned nr;
+
+		pr_warn("More than 8 CPUs detected - skipping them\n"
+			"Use CONFIG_X86_BIGSMP\n");
+
+		nr = 0;
+		for_each_present_cpu(cpu) {
+			if (nr >= 8)
+				set_cpu_present(cpu, false);
+			nr++;
+		}
+
+		nr = 0;
+		for_each_possible_cpu(cpu) {
+			if (nr >= 8)
+				set_cpu_possible(cpu, false);
+			nr++;
+		}
+
+		nr_cpu_ids = 8;
+	}
+#endif
+
+	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
+		pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n",
+			hard_smp_processor_id());
+
+		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
+	}
+
+	/*
+	 * If we couldn't find an SMP configuration at boot time,
+	 * get out of here now!
+	 */
+	if (!smp_found_config && !acpi_lapic) {
+		preempt_enable();
+		pr_notice("SMP motherboard not detected\n");
+		return SMP_NO_CONFIG;
+	}
+
+	/*
+	 * Should not be necessary because the MP table should list the boot
+	 * CPU too, but we do it for the sake of robustness anyway.
+	 */
+	if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
+		pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n",
+			  boot_cpu_physical_apicid);
+		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
+	}
+	preempt_enable();
+
+	/*
+	 * If we couldn't find a local APIC, then get out of here now!
+	 */
+	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
+	    !cpu_has_apic) {
+		if (!disable_apic) {
+			pr_err("BIOS bug, local APIC #%d not detected!...\n",
+				boot_cpu_physical_apicid);
+			pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
+		}
+		return SMP_NO_APIC;
+	}
+
+	/*
+	 * If SMP should be disabled, then really disable it!
+	 */
+	if (!max_cpus) {
+		pr_info("SMP mode deactivated\n");
+		return SMP_FORCE_UP;
+	}
+
+	return SMP_OK;
+}
+
+static void __init smp_cpu_index_default(void)
+{
+	int i;
+	struct cpuinfo_x86 *c;
+
+	for_each_possible_cpu(i) {
+		c = &cpu_data(i);
+		/* mark all to hotplug */
+		c->cpu_index = nr_cpu_ids;
+	}
+}
+
+/*
+ * Prepare for SMP bootup.  The MP table or ACPI has been read
+ * earlier.  Just do some sanity checking here and enable APIC mode.
+ */
+void __init native_smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned int i;
+
+	smp_cpu_index_default();
+
+	/*
+	 * Setup boot CPU information
+	 */
+	smp_store_boot_cpu_info(); /* Final full version of the data */
+	cpumask_copy(cpu_callin_mask, cpumask_of(0));
+	mb();
+
+	current_thread_info()->cpu = 0;  /* needed? */
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
+	}
+	set_cpu_sibling_map(0);
+
+	switch (smp_sanity_check(max_cpus)) {
+	case SMP_NO_CONFIG:
+		disable_smp();
+		if (APIC_init_uniprocessor())
+			pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");
+		return;
+	case SMP_NO_APIC:
+		disable_smp();
+		return;
+	case SMP_FORCE_UP:
+		disable_smp();
+		apic_bsp_setup(false);
+		return;
+	case SMP_OK:
+		break;
+	}
+
+	default_setup_apic_routing();
+
+	if (read_apic_id() != boot_cpu_physical_apicid) {
+		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
+		     read_apic_id(), boot_cpu_physical_apicid);
+		/* Or can we switch back to PIC here? */
+	}
+
+	cpu0_logical_apicid = apic_bsp_setup(false);
+
+	pr_info("CPU%d: ", 0);
+	print_cpu_info(&cpu_data(0));
+
+	if (is_uv_system())
+		uv_system_init();
+
+	set_mtrr_aps_delayed_init();
+}
+
+void arch_enable_nonboot_cpus_begin(void)
+{
+	set_mtrr_aps_delayed_init();
+}
+
+void arch_enable_nonboot_cpus_end(void)
+{
+	mtrr_aps_init();
+}
+
+/*
+ * Early setup to make printk work.
+ */
+void __init native_smp_prepare_boot_cpu(void)
+{
+	int me = smp_processor_id();
+	switch_to_new_gdt(me);
+	/* already set me in cpu_online_mask in boot_cpu_init() */
+	cpumask_set_cpu(me, cpu_callout_mask);
+	cpu_set_state_online(me);
+}
+
+void __init native_smp_cpus_done(unsigned int max_cpus)
+{
+	pr_debug("Boot done\n");
+
+	nmi_selftest();
+	impress_friends();
+	setup_ioapic_dest();
+	mtrr_aps_init();
+}
+
+static int __initdata setup_possible_cpus = -1;
+static int __init _setup_possible_cpus(char *str)
+{
+	get_option(&str, &setup_possible_cpus);
+	return 0;
+}
+early_param("possible_cpus", _setup_possible_cpus);
+
+
+/*
+ * cpu_possible_mask should be static, it cannot change as cpu's
+ * are onlined, or offlined. The reason is per-cpu data-structures
+ * are allocated by some modules at init time, and dont expect to
+ * do this dynamically on cpu arrival/departure.
+ * cpu_present_mask on the other hand can change dynamically.
+ * In case when cpu_hotplug is not compiled, then we resort to current
+ * behaviour, which is cpu_possible == cpu_present.
+ * - Ashok Raj
+ *
+ * Three ways to find out the number of additional hotplug CPUs:
+ * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
+ * - The user can overwrite it with possible_cpus=NUM
+ * - Otherwise don't reserve additional CPUs.
+ * We do this because additional CPUs waste a lot of memory.
+ * -AK
+ */
+__init void prefill_possible_map(void)
+{
+	int i, possible;
+
+	/* no processor from mptable or madt */
+	if (!num_processors)
+		num_processors = 1;
+
+	i = setup_max_cpus ?: 1;
+	if (setup_possible_cpus == -1) {
+		possible = num_processors;
+#ifdef CONFIG_HOTPLUG_CPU
+		if (setup_max_cpus)
+			possible += disabled_cpus;
+#else
+		if (possible > i)
+			possible = i;
+#endif
+	} else
+		possible = setup_possible_cpus;
+
+	total_cpus = max_t(int, possible, num_processors + disabled_cpus);
+
+	/* nr_cpu_ids could be reduced via nr_cpus= */
+	if (possible > nr_cpu_ids) {
+		pr_warn("%d Processors exceeds NR_CPUS limit of %d\n",
+			possible, nr_cpu_ids);
+		possible = nr_cpu_ids;
+	}
+
+#ifdef CONFIG_HOTPLUG_CPU
+	if (!setup_max_cpus)
+#endif
+	if (possible > i) {
+		pr_warn("%d Processors exceeds max_cpus limit of %u\n",
+			possible, setup_max_cpus);
+		possible = i;
+	}
+
+	pr_info("Allowing %d CPUs, %d hotplug CPUs\n",
+		possible, max_t(int, possible - num_processors, 0));
+
+	for (i = 0; i < possible; i++)
+		set_cpu_possible(i, true);
+	for (; i < NR_CPUS; i++)
+		set_cpu_possible(i, false);
+
+	nr_cpu_ids = possible;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static void remove_siblinginfo(int cpu)
+{
+	int sibling;
+	struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+	for_each_cpu(sibling, cpu_core_mask(cpu)) {
+		cpumask_clear_cpu(cpu, cpu_core_mask(sibling));
+		/*/
+		 * last thread sibling in this cpu core going down
+		 */
+		if (cpumask_weight(cpu_sibling_mask(cpu)) == 1)
+			cpu_data(sibling).booted_cores--;
+	}
+
+	for_each_cpu(sibling, cpu_sibling_mask(cpu))
+		cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
+	for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
+		cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
+	cpumask_clear(cpu_llc_shared_mask(cpu));
+	cpumask_clear(cpu_sibling_mask(cpu));
+	cpumask_clear(cpu_core_mask(cpu));
+	c->phys_proc_id = 0;
+	c->cpu_core_id = 0;
+	cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
+}
+
+static void __ref remove_cpu_from_maps(int cpu)
+{
+	set_cpu_online(cpu, false);
+	cpumask_clear_cpu(cpu, cpu_callout_mask);
+	cpumask_clear_cpu(cpu, cpu_callin_mask);
+	/* was set by cpu_init() */
+	cpumask_clear_cpu(cpu, cpu_initialized_mask);
+	numa_remove_cpu(cpu);
+}
+
+void cpu_disable_common(void)
+{
+	int cpu = smp_processor_id();
+
+	remove_siblinginfo(cpu);
+
+	/* It's now safe to remove this processor from the online map */
+	lock_vector_lock();
+	remove_cpu_from_maps(cpu);
+	unlock_vector_lock();
+	fixup_irqs();
+}
+
+int native_cpu_disable(void)
+{
+	int ret;
+
+	ret = check_irq_vectors_for_cpu_disable();
+	if (ret)
+		return ret;
+
+	clear_local_APIC();
+	cpu_disable_common();
+
+	return 0;
+}
+
+int common_cpu_die(unsigned int cpu)
+{
+	int ret = 0;
+
+	/* We don't do anything here: idle task is faking death itself. */
+
+	/* They ack this in play_dead() by setting CPU_DEAD */
+	if (cpu_wait_death(cpu, 5)) {
+		if (system_state == SYSTEM_RUNNING)
+			pr_info("CPU %u is now offline\n", cpu);
+	} else {
+		pr_err("CPU %u didn't die...\n", cpu);
+		ret = -1;
+	}
+
+	return ret;
+}
+
+void native_cpu_die(unsigned int cpu)
+{
+	common_cpu_die(cpu);
+}
+
+void play_dead_common(void)
+{
+	idle_task_exit();
+	reset_lazy_tlbstate();
+	amd_e400_remove_cpu(raw_smp_processor_id());
+
+	/* Ack it */
+	(void)cpu_report_death();
+
+	/*
+	 * With physical CPU hotplug, we should halt the cpu
+	 */
+	local_irq_disable();
+}
+
+static bool wakeup_cpu0(void)
+{
+	if (smp_processor_id() == 0 && enable_start_cpu0)
+		return true;
+
+	return false;
+}
+
+/*
+ * We need to flush the caches before going to sleep, lest we have
+ * dirty data in our caches when we come back up.
+ */
+static inline void mwait_play_dead(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int highest_cstate = 0;
+	unsigned int highest_subcstate = 0;
+	void *mwait_ptr;
+	int i;
+
+	if (!this_cpu_has(X86_FEATURE_MWAIT))
+		return;
+	if (!this_cpu_has(X86_FEATURE_CLFLUSH))
+		return;
+	if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
+		return;
+
+	eax = CPUID_MWAIT_LEAF;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+
+	/*
+	 * eax will be 0 if EDX enumeration is not valid.
+	 * Initialized below to cstate, sub_cstate value when EDX is valid.
+	 */
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
+		eax = 0;
+	} else {
+		edx >>= MWAIT_SUBSTATE_SIZE;
+		for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
+			if (edx & MWAIT_SUBSTATE_MASK) {
+				highest_cstate = i;
+				highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
+			}
+		}
+		eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
+			(highest_subcstate - 1);
+	}
+
+	/*
+	 * This should be a memory location in a cache line which is
+	 * unlikely to be touched by other processors.  The actual
+	 * content is immaterial as it is not actually modified in any way.
+	 */
+	mwait_ptr = &current_thread_info()->flags;
+
+	wbinvd();
+
+	while (1) {
+		/*
+		 * The CLFLUSH is a workaround for erratum AAI65 for
+		 * the Xeon 7400 series.  It's not clear it is actually
+		 * needed, but it should be harmless in either case.
+		 * The WBINVD is insufficient due to the spurious-wakeup
+		 * case where we return around the loop.
+		 */
+		mb();
+		clflush(mwait_ptr);
+		mb();
+		__monitor(mwait_ptr, 0, 0);
+		mb();
+		__mwait(eax, 0);
+		/*
+		 * If NMI wants to wake up CPU0, start CPU0.
+		 */
+		if (wakeup_cpu0())
+			start_cpu0();
+	}
+}
+
+static inline void hlt_play_dead(void)
+{
+	if (__this_cpu_read(cpu_info.x86) >= 4)
+		wbinvd();
+
+	while (1) {
+		native_halt();
+		/*
+		 * If NMI wants to wake up CPU0, start CPU0.
+		 */
+		if (wakeup_cpu0())
+			start_cpu0();
+	}
+}
+
+void native_play_dead(void)
+{
+	play_dead_common();
+	tboot_shutdown(TB_SHUTDOWN_WFS);
+
+	mwait_play_dead();	/* Only returns on failure */
+	if (cpuidle_play_dead())
+		hlt_play_dead();
+}
+
+#else /* ... !CONFIG_HOTPLUG_CPU */
+int native_cpu_disable(void)
+{
+	return -ENOSYS;
+}
+
+void native_cpu_die(unsigned int cpu)
+{
+	/* We said "no" in __cpu_disable */
+	BUG();
+}
+
+void native_play_dead(void)
+{
+	BUG();
+}
+
+#endif