diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 6ec5217..72f40ca 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -130,12 +130,6 @@
 	mdelay((10*1000)/nmi_hz); // wait 10 ticks
 
 	for (cpu = 0; cpu < NR_CPUS; cpu++) {
-#ifdef CONFIG_SMP
-		/* Check cpu_callin_map here because that is set
-		   after the timer is started. */
-		if (!cpu_isset(cpu, cpu_callin_map))
-			continue;
-#endif
 		if (cpu_pda[cpu].__nmi_count - counts[cpu] <= 5) {
 			printk("CPU#%d: NMI appears to be stuck (%d)!\n", 
 			       cpu,
diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index e3cdbf9..1e379ed 100644
--- a/arch/x86_64/kernel/smp.c
+++ b/arch/x86_64/kernel/smp.c
@@ -27,6 +27,7 @@
 #include <asm/mach_apic.h>
 #include <asm/mmu_context.h>
 #include <asm/proto.h>
+#include <asm/apicdef.h>
 
 /*
  *	Smarter SMP flushing macros. 
@@ -413,3 +414,27 @@
 		atomic_inc(&call_data->finished);
 	}
 }
+
+int safe_smp_processor_id(void)
+{
+	int apicid, i;
+
+	if (disable_apic)
+		return 0;
+
+	apicid = hard_smp_processor_id();
+	if (x86_cpu_to_apicid[apicid] == apicid)
+		return apicid;
+
+	for (i = 0; i < NR_CPUS; ++i) {
+		if (x86_cpu_to_apicid[i] == apicid)
+			return i;
+	}
+
+	/* No entries in x86_cpu_to_apicid?  Either no MPS|ACPI,
+	 * or called too early.  Either way, we must be CPU 0. */
+      	if (x86_cpu_to_apicid[0] == BAD_APICID)
+		return 0;
+
+	return 0; /* Should not happen */
+}
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index 7e2de89..eca01e8 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -12,8 +12,7 @@
  *	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.
+ *	This code is released under the GNU General Public License version 2
  *
  *	Fixes
  *		Felix Koop	:	NR_CPUS used properly
@@ -31,9 +30,13 @@
  *		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.
- *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process. 
+ *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process.
+ *      Andi Kleen              :       Converted to new state machine.
+ *					Various cleanups.
+ *					Probably mostly hotplug CPU ready now.
  */
 
+
 #include <linux/config.h>
 #include <linux/init.h>
 
@@ -54,11 +57,15 @@
 #include <asm/tlbflush.h>
 #include <asm/proto.h>
 
+/* Change for real CPU hotplug. Note other files need to be fixed
+   first too. */
+#define __cpuinit __init
+#define __cpuinitdata __initdata
+
 /* Number of siblings per CPU package */
 int smp_num_siblings = 1;
 /* Package ID of each logical CPU */
 u8 phys_proc_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
-/* Core ID of each logical CPU */
 u8 cpu_core_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(phys_proc_id);
 EXPORT_SYMBOL(cpu_core_id);
@@ -66,13 +73,24 @@
 /* Bitmask of currently online CPUs */
 cpumask_t cpu_online_map;
 
+EXPORT_SYMBOL(cpu_online_map);
+
+/*
+ * Private maps to synchronize booting between AP and BP.
+ * Probably not needed anymore, but it makes for easier debugging. -AK
+ */
 cpumask_t cpu_callin_map;
 cpumask_t cpu_callout_map;
-static cpumask_t smp_commenced_mask;
+
+cpumask_t cpu_possible_map;
+EXPORT_SYMBOL(cpu_possible_map);
 
 /* Per CPU bogomips and other parameters */
 struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned;
 
+/* Set when the idlers are all forked */
+int smp_threads_ready;
+
 cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 
@@ -80,8 +98,8 @@
  * Trampoline 80x86 program as an array.
  */
 
-extern unsigned char trampoline_data [];
-extern unsigned char trampoline_end  [];
+extern unsigned char trampoline_data[];
+extern unsigned char trampoline_end[];
 
 /*
  * Currently trivial. Write the real->protected mode
@@ -89,7 +107,7 @@
  * has made sure it's suitably aligned.
  */
 
-static unsigned long __init setup_trampoline(void)
+static unsigned long __cpuinit setup_trampoline(void)
 {
 	void *tramp = __va(SMP_TRAMPOLINE_BASE); 
 	memcpy(tramp, trampoline_data, trampoline_end - trampoline_data);
@@ -101,7 +119,7 @@
  * a given CPU
  */
 
-static void __init smp_store_cpu_info(int id)
+static void __cpuinit smp_store_cpu_info(int id)
 {
 	struct cpuinfo_x86 *c = cpu_data + id;
 
@@ -110,145 +128,101 @@
 }
 
 /*
- * TSC synchronization.
+ * Synchronize TSCs of CPUs
  *
- * We first check whether all CPUs have their TSC's synchronized,
- * then we print a warning if not, and always resync.
+ * This new algorithm is less accurate than the old "zero TSCs"
+ * one, but we cannot zero TSCs anymore in the new hotplug CPU
+ * model.
  */
 
-static atomic_t tsc_start_flag = ATOMIC_INIT(0);
-static atomic_t tsc_count_start = ATOMIC_INIT(0);
-static atomic_t tsc_count_stop = ATOMIC_INIT(0);
-static unsigned long long tsc_values[NR_CPUS];
+static atomic_t __cpuinitdata tsc_flag;
+static __cpuinitdata DEFINE_SPINLOCK(tsc_sync_lock);
+static unsigned long long __cpuinitdata bp_tsc, ap_tsc;
 
 #define NR_LOOPS 5
 
-extern unsigned int fast_gettimeoffset_quotient;
-
-static void __init synchronize_tsc_bp (void)
+static void __cpuinit sync_tsc_bp_init(int init)
 {
-	int i;
-	unsigned long long t0;
-	unsigned long long sum, avg;
-	long long delta;
-	long one_usec;
-	int buggy = 0;
-
-	printk(KERN_INFO "checking TSC synchronization across %u CPUs: ",num_booting_cpus());
-
-	one_usec = cpu_khz; 
-
-	atomic_set(&tsc_start_flag, 1);
-	wmb();
-
-	/*
-	 * We loop a few times to get a primed instruction cache,
-	 * then the last pass is more or less synchronized and
-	 * the BP and APs set their cycle counters to zero all at
-	 * once. This reduces the chance of having random offsets
-	 * between the processors, and guarantees that the maximum
-	 * delay between the cycle counters is never bigger than
-	 * the latency of information-passing (cachelines) between
-	 * two CPUs.
-	 */
-	for (i = 0; i < NR_LOOPS; i++) {
-		/*
-		 * all APs synchronize but they loop on '== num_cpus'
-		 */
-		while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) mb();
-		atomic_set(&tsc_count_stop, 0);
-		wmb();
-		/*
-		 * this lets the APs save their current TSC:
-		 */
-		atomic_inc(&tsc_count_start);
-
-		sync_core();
-		rdtscll(tsc_values[smp_processor_id()]);
-		/*
-		 * We clear the TSC in the last loop:
-		 */
-		if (i == NR_LOOPS-1)
-			write_tsc(0, 0);
-
-		/*
-		 * Wait for all APs to leave the synchronization point:
-		 */
-		while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) mb();
-		atomic_set(&tsc_count_start, 0);
-		wmb();
-		atomic_inc(&tsc_count_stop);
-	}
-
-	sum = 0;
-	for (i = 0; i < NR_CPUS; i++) {
-		if (cpu_isset(i, cpu_callout_map)) {
-		t0 = tsc_values[i];
-		sum += t0;
-	}
-	}
-	avg = sum / num_booting_cpus();
-
-	sum = 0;
-	for (i = 0; i < NR_CPUS; i++) {
-		if (!cpu_isset(i, cpu_callout_map))
-			continue;
-
-		delta = tsc_values[i] - avg;
-		if (delta < 0)
-			delta = -delta;
-		/*
-		 * We report bigger than 2 microseconds clock differences.
-		 */
-		if (delta > 2*one_usec) {
-			long realdelta;
-			if (!buggy) {
-				buggy = 1;
-				printk("\n");
-			}
-			realdelta = delta / one_usec;
-			if (tsc_values[i] < avg)
-				realdelta = -realdelta;
-
-			printk("BIOS BUG: CPU#%d improperly initialized, has %ld usecs TSC skew! FIXED.\n",
-				i, realdelta);
-		}
-
-		sum += delta;
-	}
-	if (!buggy)
-		printk("passed.\n");
+	if (init)
+		_raw_spin_lock(&tsc_sync_lock);
+	else
+		_raw_spin_unlock(&tsc_sync_lock);
+	atomic_set(&tsc_flag, 0);
 }
 
-static void __init synchronize_tsc_ap (void)
+/*
+ * Synchronize TSC on AP with BP.
+ */
+static void __cpuinit __sync_tsc_ap(void)
+{
+	if (!cpu_has_tsc)
+		return;
+	Dprintk("AP %d syncing TSC\n", smp_processor_id());
+
+	while (atomic_read(&tsc_flag) != 0)
+		cpu_relax();
+	atomic_inc(&tsc_flag);
+	mb();
+	_raw_spin_lock(&tsc_sync_lock);
+	wrmsrl(MSR_IA32_TSC, bp_tsc);
+	_raw_spin_unlock(&tsc_sync_lock);
+	rdtscll(ap_tsc);
+	mb();
+	atomic_inc(&tsc_flag);
+	mb();
+}
+
+static void __cpuinit sync_tsc_ap(void)
 {
 	int i;
-
-	/*
-	 * Not every cpu is online at the time
-	 * this gets called, so we first wait for the BP to
-	 * finish SMP initialization:
-	 */
-	while (!atomic_read(&tsc_start_flag)) mb();
-
-	for (i = 0; i < NR_LOOPS; i++) {
-		atomic_inc(&tsc_count_start);
-		while (atomic_read(&tsc_count_start) != num_booting_cpus()) mb();
-
-		sync_core();
-		rdtscll(tsc_values[smp_processor_id()]);
-		if (i == NR_LOOPS-1)
-			write_tsc(0, 0);
-
-		atomic_inc(&tsc_count_stop);
-		while (atomic_read(&tsc_count_stop) != num_booting_cpus()) mb();
-	}
+	for (i = 0; i < NR_LOOPS; i++)
+		__sync_tsc_ap();
 }
-#undef NR_LOOPS
 
-static atomic_t init_deasserted;
+/*
+ * Synchronize TSC from BP to AP.
+ */
+static void __cpuinit __sync_tsc_bp(int cpu)
+{
+	if (!cpu_has_tsc)
+		return;
 
-static void __init smp_callin(void)
+	/* Wait for AP */
+	while (atomic_read(&tsc_flag) == 0)
+		cpu_relax();
+	/* Save BPs TSC */
+	sync_core();
+	rdtscll(bp_tsc);
+	/* Don't do the sync core here to avoid too much latency. */
+	mb();
+	/* Start the AP */
+	_raw_spin_unlock(&tsc_sync_lock);
+	/* Wait for AP again */
+	while (atomic_read(&tsc_flag) < 2)
+		cpu_relax();
+	rdtscl(bp_tsc);
+	barrier();
+}
+
+static void __cpuinit sync_tsc_bp(int cpu)
+{
+	int i;
+	for (i = 0; i < NR_LOOPS - 1; i++) {
+		__sync_tsc_bp(cpu);
+		sync_tsc_bp_init(1);
+	}
+	__sync_tsc_bp(cpu);
+	printk(KERN_INFO "Synced TSC of CPU %d difference %Ld\n",
+	       cpu, ap_tsc - bp_tsc);
+}
+
+static atomic_t init_deasserted __cpuinitdata;
+
+/*
+ * Report back to the Boot Processor.
+ * Running on AP.
+ */
+void __cpuinit smp_callin(void)
 {
 	int cpuid, phys_id;
 	unsigned long timeout;
@@ -259,7 +233,8 @@
 	 * our local APIC.  We have to wait for the IPI or we'll
 	 * lock up on an APIC access.
 	 */
-	while (!atomic_read(&init_deasserted));
+	while (!atomic_read(&init_deasserted))
+		cpu_relax();
 
 	/*
 	 * (This works even if the APIC is not enabled.)
@@ -290,7 +265,7 @@
 		 */
 		if (cpu_isset(cpuid, cpu_callout_map))
 			break;
-		rep_nop();
+		cpu_relax();
 	}
 
 	if (!time_before(jiffies, timeout)) {
@@ -325,20 +300,12 @@
 	 * Allow the master to continue.
 	 */
 	cpu_set(cpuid, cpu_callin_map);
-
-	/*
-	 *      Synchronize the TSC with the BP
-	 */
-	if (cpu_has_tsc)
-		synchronize_tsc_ap();
 }
 
-static int cpucount;
-
 /*
- * Activate a secondary processor.
+ * Setup code on secondary processor (after comming out of the trampoline)
  */
-void __init start_secondary(void)
+void __cpuinit start_secondary(void)
 {
 	/*
 	 * Dont put anything before smp_callin(), SMP
@@ -348,17 +315,18 @@
 	cpu_init();
 	smp_callin();
 
+	/*
+	 * Synchronize the TSC with the BP
+	 */
+	sync_tsc_ap();
+
 	/* otherwise gcc will move up the smp_processor_id before the cpu_init */
 	barrier();
 
-	Dprintk("cpu %d: waiting for commence\n", smp_processor_id()); 
-	while (!cpu_isset(smp_processor_id(), smp_commenced_mask))
-		rep_nop();
-
 	Dprintk("cpu %d: setting up apic clock\n", smp_processor_id()); 	
 	setup_secondary_APIC_clock();
 
-	Dprintk("cpu %d: enabling apic timer\n", smp_processor_id()); 
+	Dprintk("cpu %d: enabling apic timer\n", smp_processor_id());
 
 	if (nmi_watchdog == NMI_IO_APIC) {
 		disable_8259A_irq(0);
@@ -367,26 +335,22 @@
 	}
 
 
-	enable_APIC_timer(); 
+	enable_APIC_timer();
 
 	/*
-	 * low-memory mappings have been cleared, flush them from
-	 * the local TLBs too.
+	 * Allow the master to continue.
 	 */
-	local_flush_tlb();
-
-	Dprintk("cpu %d eSetting cpu_online_map\n", smp_processor_id()); 
 	cpu_set(smp_processor_id(), cpu_online_map);
-	wmb();
-	
+	mb();
+
 	cpu_idle();
 }
 
-extern volatile unsigned long init_rsp; 
+extern volatile unsigned long init_rsp;
 extern void (*initial_code)(void);
 
 #if APIC_DEBUG
-static inline void inquire_remote_apic(int apicid)
+static void inquire_remote_apic(int apicid)
 {
 	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
 	char *names[] = { "ID", "VERSION", "SPIV" };
@@ -423,7 +387,10 @@
 }
 #endif
 
-static int __init wakeup_secondary_via_INIT(int phys_apicid, unsigned int start_rip)
+/*
+ * Kick the secondary to wake up.
+ */
+static int __cpuinit wakeup_secondary_via_INIT(int phys_apicid, unsigned int start_rip)
 {
 	unsigned long send_status = 0, accept_status = 0;
 	int maxlvt, timeout, num_starts, j;
@@ -546,33 +513,36 @@
 	return (send_status | accept_status);
 }
 
-static void __init do_boot_cpu (int apicid)
+/*
+ * Boot one CPU.
+ */
+static int __cpuinit do_boot_cpu(int cpu, int apicid)
 {
 	struct task_struct *idle;
 	unsigned long boot_error;
-	int timeout, cpu;
+	int timeout;
 	unsigned long start_rip;
-
-	cpu = ++cpucount;
 	/*
 	 * We can't use kernel_thread since we must avoid to
 	 * reschedule the child.
 	 */
 	idle = fork_idle(cpu);
-	if (IS_ERR(idle))
-		panic("failed fork for CPU %d", cpu);
+	if (IS_ERR(idle)) {
+		printk("failed fork for CPU %d\n", cpu);
+		return PTR_ERR(idle);
+	}
 	x86_cpu_to_apicid[cpu] = apicid;
 
 	cpu_pda[cpu].pcurrent = idle;
 
 	start_rip = setup_trampoline();
 
-	init_rsp = idle->thread.rsp; 
+	init_rsp = idle->thread.rsp;
 	per_cpu(init_tss,cpu).rsp0 = init_rsp;
 	initial_code = start_secondary;
 	clear_ti_thread_flag(idle->thread_info, TIF_FORK);
 
-	printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid, 
+	printk(KERN_INFO "Booting processor %d/%d rip %lx rsp %lx\n", cpu, apicid,
 	       start_rip, init_rsp);
 
 	/*
@@ -609,7 +579,7 @@
 	/*
 	 * Starting actual IPI sequence...
 	 */
-	boot_error = wakeup_secondary_via_INIT(apicid, start_rip); 
+	boot_error = wakeup_secondary_via_INIT(apicid, start_rip);
 
 	if (!boot_error) {
 		/*
@@ -650,58 +620,131 @@
 	if (boot_error) {
 		cpu_clear(cpu, cpu_callout_map); /* was set here (do_boot_cpu()) */
 		clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */
-		cpucount--;
+		cpu_clear(cpu, cpu_present_map);
+		cpu_clear(cpu, cpu_possible_map);
 		x86_cpu_to_apicid[cpu] = BAD_APICID;
 		x86_cpu_to_log_apicid[cpu] = BAD_APICID;
+		return -EIO;
+	}
+
+	return 0;
+}
+
+cycles_t cacheflush_time;
+unsigned long cache_decay_ticks;
+
+/*
+ * Construct cpu_sibling_map[], so that we can tell the sibling CPU
+ * on SMT systems efficiently.
+ */
+static __cpuinit void detect_siblings(void)
+{
+	int cpu;
+
+	for (cpu = 0; cpu < NR_CPUS; cpu++) {
+		cpus_clear(cpu_sibling_map[cpu]);
+		cpus_clear(cpu_core_map[cpu]);
+	}
+
+	for_each_online_cpu (cpu) {
+		struct cpuinfo_x86 *c = cpu_data + cpu;
+		int siblings = 0;
+		int i;
+		if (smp_num_siblings > 1) {
+			for_each_online_cpu (i) {
+				if (cpu_core_id[cpu] == phys_proc_id[i]) {
+					siblings++;
+					cpu_set(i, cpu_sibling_map[cpu]);
+				}
+			}
+		} else {
+			siblings++;
+			cpu_set(cpu, cpu_sibling_map[cpu]);
+		}
+
+		if (siblings != smp_num_siblings) {
+			printk(KERN_WARNING
+	       "WARNING: %d siblings found for CPU%d, should be %d\n",
+			       siblings, cpu, smp_num_siblings);
+			smp_num_siblings = siblings;
+		}
+		if (c->x86_num_cores > 1) {
+			for_each_online_cpu(i) {
+				if (phys_proc_id[cpu] == phys_proc_id[i])
+					cpu_set(i, cpu_core_map[cpu]);
+			}
+		} else
+			cpu_core_map[cpu] = cpu_sibling_map[cpu];
 	}
 }
 
-static void smp_tune_scheduling (void)
+/*
+ * Cleanup possible dangling ends...
+ */
+static __cpuinit void smp_cleanup_boot(void)
 {
-	int cachesize;       /* kB   */
-	unsigned long bandwidth = 1000; /* MB/s */
 	/*
-	 * Rough estimation for SMP scheduling, this is the number of
-	 * cycles it takes for a fully memory-limited process to flush
-	 * the SMP-local cache.
-	 *
-	 * (For a P5 this pretty much means we will choose another idle
-	 *  CPU almost always at wakeup time (this is due to the small
-	 *  L1 cache), on PIIs it's around 50-100 usecs, depending on
-	 *  the cache size)
+	 * Paranoid:  Set warm reset code and vector here back
+	 * to default values.
+	 */
+	CMOS_WRITE(0, 0xf);
+
+	/*
+	 * Reset trampoline flag
+	 */
+	*((volatile int *) phys_to_virt(0x467)) = 0;
+
+#ifndef CONFIG_HOTPLUG_CPU
+	/*
+	 * Free pages reserved for SMP bootup.
+	 * When you add hotplug CPU support later remove this
+	 * Note there is more work to be done for later CPU bootup.
 	 */
 
-	if (!cpu_khz) {
-		return;
-	} else {
-		cachesize = boot_cpu_data.x86_cache_size;
-		if (cachesize == -1) {
-			cachesize = 16; /* Pentiums, 2x8kB cache */
-			bandwidth = 100;
+	free_page((unsigned long) __va(PAGE_SIZE));
+	free_page((unsigned long) __va(SMP_TRAMPOLINE_BASE));
+#endif
+}
+
+/*
+ * Fall back to non SMP mode after errors.
+ *
+ * RED-PEN audit/test this more. I bet there is more state messed up here.
+ */
+static __cpuinit void disable_smp(void)
+{
+	cpu_present_map = cpumask_of_cpu(0);
+	cpu_possible_map = cpumask_of_cpu(0);
+	if (smp_found_config)
+		phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
+	else
+		phys_cpu_present_map = physid_mask_of_physid(0);
+	cpu_set(0, cpu_sibling_map[0]);
+	cpu_set(0, cpu_core_map[0]);
+}
+
+/*
+ * Handle user cpus=... parameter.
+ */
+static __cpuinit void enforce_max_cpus(unsigned max_cpus)
+{
+	int i, k;
+	k = 0;
+	for (i = 0; i < NR_CPUS; i++) {
+		if (!cpu_possible(i))
+			continue;
+		if (++k > max_cpus) {
+			cpu_clear(i, cpu_possible_map);
+			cpu_clear(i, cpu_present_map);
 		}
 	}
 }
 
 /*
- * Cycle through the processors sending APIC IPIs to boot each.
+ * Various sanity checks.
  */
-
-static void __init smp_boot_cpus(unsigned int max_cpus)
+static int __cpuinit smp_sanity_check(unsigned max_cpus)
 {
-	unsigned apicid, cpu, bit, kicked;
-
-	nmi_watchdog_default();
-
-	/*
-	 * Setup boot CPU information
-	 */
-	smp_store_cpu_info(0); /* Final full version of the data */
-	printk(KERN_INFO "CPU%d: ", 0);
-	print_cpu_info(&cpu_data[0]);
-
-	current_thread_info()->cpu = 0;
-	smp_tune_scheduling();
-
 	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
 		printk("weird, boot CPU (#%d) not listed by the BIOS.\n",
 		       hard_smp_processor_id());
@@ -714,15 +757,11 @@
 	 */
 	if (!smp_found_config) {
 		printk(KERN_NOTICE "SMP motherboard not detected.\n");
-		io_apic_irqs = 0;
-		cpu_online_map = cpumask_of_cpu(0);
-		cpu_set(0, cpu_sibling_map[0]);
-		cpu_set(0, cpu_core_map[0]);
-		phys_cpu_present_map = physid_mask_of_physid(0);
+		disable_smp();
 		if (APIC_init_uniprocessor())
 			printk(KERN_NOTICE "Local APIC not detected."
 					   " Using dummy APIC emulation.\n");
-		goto smp_done;
+		return -1;
 	}
 
 	/*
@@ -742,213 +781,146 @@
 		printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
 			boot_cpu_id);
 		printk(KERN_ERR "... forcing use of dummy APIC emulation. (tell your hw vendor)\n");
-		io_apic_irqs = 0;
-		cpu_online_map = cpumask_of_cpu(0);
-		cpu_set(0, cpu_sibling_map[0]);
-		cpu_set(0, cpu_core_map[0]);
-		phys_cpu_present_map = physid_mask_of_physid(0);
-		disable_apic = 1;
-		goto smp_done;
+		nr_ioapics = 0;
+		return -1;
 	}
 
-	verify_local_APIC();
-
 	/*
 	 * If SMP should be disabled, then really disable it!
 	 */
 	if (!max_cpus) {
-		smp_found_config = 0;
 		printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
-		io_apic_irqs = 0;
-		cpu_online_map = cpumask_of_cpu(0);
-		cpu_set(0, cpu_sibling_map[0]);
-		cpu_set(0, cpu_core_map[0]);
-		phys_cpu_present_map = physid_mask_of_physid(0);
-		disable_apic = 1;
-		goto smp_done;
+		nr_ioapics = 0;
+		return -1;
 	}
 
+	return 0;
+}
+
+/*
+ * Prepare for SMP bootup.  The MP table or ACPI has been read
+ * earlier.  Just do some sanity checking here and enable APIC mode.
+ */
+void __cpuinit smp_prepare_cpus(unsigned int max_cpus)
+{
+	int i;
+
+	nmi_watchdog_default();
+	current_cpu_data = boot_cpu_data;
+	current_thread_info()->cpu = 0;  /* needed? */
+
+	enforce_max_cpus(max_cpus);
+
+	/*
+	 * Fill in cpu_present_mask
+	 */
+	for (i = 0; i < NR_CPUS; i++) {
+		int apicid = cpu_present_to_apicid(i);
+		if (physid_isset(apicid, phys_cpu_present_map)) {
+			cpu_set(i, cpu_present_map);
+			/* possible map would be different if we supported real
+			   CPU hotplug. */
+			cpu_set(i, cpu_possible_map);
+		}
+	}
+
+	if (smp_sanity_check(max_cpus) < 0) {
+		printk(KERN_INFO "SMP disabled\n");
+		disable_smp();
+		return;
+	}
+
+
+	/*
+	 * Switch from PIC to APIC mode.
+	 */
 	connect_bsp_APIC();
 	setup_local_APIC();
 
-	if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id)
-		BUG();
-
+	if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id) {
+		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
+		      GET_APIC_ID(apic_read(APIC_ID)), boot_cpu_id);
+		/* Or can we switch back to PIC here? */
+	}
 	x86_cpu_to_apicid[0] = boot_cpu_id;
 
 	/*
-	 * Now scan the CPU present map and fire up the other CPUs.
-	 */
-	Dprintk("CPU present map: %lx\n", physids_coerce(phys_cpu_present_map));
-
-	kicked = 1;
-	for (bit = 0; kicked < NR_CPUS && bit < MAX_APICS; bit++) {
-		apicid = cpu_present_to_apicid(bit);
-		/*
-		 * Don't even attempt to start the boot CPU!
-		 */
-		if (apicid == boot_cpu_id || (apicid == BAD_APICID))
-			continue;
-
-		if (!physid_isset(apicid, phys_cpu_present_map))
-			continue;
-		if ((max_cpus >= 0) && (max_cpus <= cpucount+1))
-			continue;
-
-		do_boot_cpu(apicid);
-		++kicked;
-	}
-
-	/*
-	 * Cleanup possible dangling ends...
-	 */
-	{
-		/*
-		 * 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.
-		 */
-		CMOS_WRITE(0, 0xf);
-
-		*((volatile int *) phys_to_virt(0x467)) = 0;
-	}
-
-	/*
-	 * Allow the user to impress friends.
-	 */
-
-	Dprintk("Before bogomips.\n");
-	if (!cpucount) {
-		printk(KERN_INFO "Only one processor found.\n");
-	} else {
-		unsigned long bogosum = 0;
-		for (cpu = 0; cpu < NR_CPUS; cpu++)
-			if (cpu_isset(cpu, cpu_callout_map))
-				bogosum += cpu_data[cpu].loops_per_jiffy;
-		printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
-			cpucount+1,
-			bogosum/(500000/HZ),
-			(bogosum/(5000/HZ))%100);
-		Dprintk("Before bogocount - setting activated=1.\n");
-	}
-
-	/*
-	 * Construct cpu_sibling_map[], so that we can tell the
-	 * sibling CPU efficiently.
-	 */
-	for (cpu = 0; cpu < NR_CPUS; cpu++) {
-		cpus_clear(cpu_sibling_map[cpu]);
-		cpus_clear(cpu_core_map[cpu]);
-	}
-
-	for (cpu = 0; cpu < NR_CPUS; cpu++) {
-  		struct cpuinfo_x86 *c = cpu_data + cpu;
-		int siblings = 0;
-		int i;
-		if (!cpu_isset(cpu, cpu_callout_map))
-			continue;
-
-		if (smp_num_siblings > 1) {
-			for (i = 0; i < NR_CPUS; i++) {
-				if (!cpu_isset(i, cpu_callout_map))
-					continue;
-				if (phys_proc_id[cpu] == cpu_core_id[i]) {
-					siblings++;
-					cpu_set(i, cpu_sibling_map[cpu]);
-				}
-			}
-		} else { 
-			siblings++;
-			cpu_set(cpu, cpu_sibling_map[cpu]);
-		}
-
-		if (siblings != smp_num_siblings) {
-			printk(KERN_WARNING 
-	       "WARNING: %d siblings found for CPU%d, should be %d\n", 
-			       siblings, cpu, smp_num_siblings);
-			smp_num_siblings = siblings;
-		}       
- 		if (c->x86_num_cores > 1) {
-			for (i = 0; i < NR_CPUS; i++) {
-				if (!cpu_isset(i, cpu_callout_map))
-					continue;
- 				if (phys_proc_id[cpu] == phys_proc_id[i]) {
- 					cpu_set(i, cpu_core_map[cpu]);
- 				}
- 			}
- 		} else
- 			cpu_core_map[cpu] = cpu_sibling_map[cpu];
-	}
-
-	Dprintk("Boot done.\n");
-
-	/*
-	 * Here we can be sure that there is an IO-APIC in the system. Let's
-	 * go and set it up:
+	 * Now start the IO-APICs
 	 */
 	if (!skip_ioapic_setup && nr_ioapics)
 		setup_IO_APIC();
 	else
 		nr_ioapics = 0;
 
-	setup_boot_APIC_clock();
-
 	/*
-	 * Synchronize the TSC with the AP
+	 * Set up local APIC timer on boot CPU.
 	 */
-	if (cpu_has_tsc && cpucount)
-		synchronize_tsc_bp();
 
- smp_done:
-	time_init_smp();
+	setup_boot_APIC_clock();
 }
 
-/* These are wrappers to interface to the new boot process.  Someone
-   who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */
-void __init smp_prepare_cpus(unsigned int max_cpus)
+/*
+ * Early setup to make printk work.
+ */
+void __init smp_prepare_boot_cpu(void)
 {
-	smp_boot_cpus(max_cpus);
+	int me = smp_processor_id();
+	cpu_set(me, cpu_online_map);
+	cpu_set(me, cpu_callout_map);
 }
 
-void __devinit smp_prepare_boot_cpu(void)
+/*
+ * Entry point to boot a CPU.
+ *
+ * This is all __cpuinit, not __devinit for now because we don't support
+ * CPU hotplug (yet).
+ */
+int __cpuinit __cpu_up(unsigned int cpu)
 {
-	cpu_set(smp_processor_id(), cpu_online_map);
-	cpu_set(smp_processor_id(), cpu_callout_map);
-}
+	int err;
+	int apicid = cpu_present_to_apicid(cpu);
 
-int __devinit __cpu_up(unsigned int cpu)
-{
-	/* This only works at boot for x86.  See "rewrite" above. */
-	if (cpu_isset(cpu, smp_commenced_mask)) {
-		local_irq_enable();
-		return -ENOSYS;
+	WARN_ON(irqs_disabled());
+
+	Dprintk("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
+
+	if (apicid == BAD_APICID || apicid == boot_cpu_id ||
+	    !physid_isset(apicid, phys_cpu_present_map)) {
+		printk("__cpu_up: bad cpu %d\n", cpu);
+		return -EINVAL;
+	}
+	sync_tsc_bp_init(1);
+
+	/* Boot it! */
+	err = do_boot_cpu(cpu, apicid);
+	if (err < 0) {
+		sync_tsc_bp_init(0);
+		Dprintk("do_boot_cpu failed %d\n", err);
+		return err;
 	}
 
-	/* In case one didn't come up */
-	if (!cpu_isset(cpu, cpu_callin_map)) {
-		local_irq_enable();
-		return -EIO;
-	}
-	local_irq_enable();
+	sync_tsc_bp(cpu);
 
 	/* Unleash the CPU! */
 	Dprintk("waiting for cpu %d\n", cpu);
 
-	cpu_set(cpu, smp_commenced_mask);
 	while (!cpu_isset(cpu, cpu_online_map))
-		mb();
+		cpu_relax();
 	return 0;
 }
 
-void __init smp_cpus_done(unsigned int max_cpus)
+/*
+ * Finish the SMP boot.
+ */
+void __cpuinit smp_cpus_done(unsigned int max_cpus)
 {
+	zap_low_mappings();
+	smp_cleanup_boot();
+
 #ifdef CONFIG_X86_IO_APIC
 	setup_ioapic_dest();
 #endif
-	zap_low_mappings();
-}
 
+	detect_siblings();
+	time_init_gtod();
+}
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index c7a1b50..943a9bf 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -916,9 +916,16 @@
 	setup_irq(0, &irq0);
 
 	set_cyc2ns_scale(cpu_khz / 1000);
+
+#ifndef CONFIG_SMP
+	time_init_gtod();
+#endif
 }
 
-void __init time_init_smp(void)
+/*
+ * Decide after all CPUs are booted what mode gettimeofday should use.
+ */
+void __init time_init_gtod(void)
 {
 	char *timetype;
 
diff --git a/include/asm-x86_64/msr.h b/include/asm-x86_64/msr.h
index 66f0be1..513e52c 100644
--- a/include/asm-x86_64/msr.h
+++ b/include/asm-x86_64/msr.h
@@ -163,6 +163,7 @@
 #define EFER_NX (1<<_EFER_NX)
 
 /* Intel MSRs. Some also available on other CPUs */
+#define MSR_IA32_TSC		0x10
 #define MSR_IA32_PLATFORM_ID	0x17
 
 #define MSR_IA32_PERFCTR0      0xc1
diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h
index 217bd9a..d0f8f8b 100644
--- a/include/asm-x86_64/proto.h
+++ b/include/asm-x86_64/proto.h
@@ -29,7 +29,7 @@
 extern void ia32_syscall(void);
 extern void iommu_hole_init(void);
 
-extern void time_init_smp(void);
+extern void time_init_gtod(void);
 
 extern void do_softirq_thunk(void);
 
diff --git a/include/asm-x86_64/smp.h b/include/asm-x86_64/smp.h
index f5eaa1a..96844fe 100644
--- a/include/asm-x86_64/smp.h
+++ b/include/asm-x86_64/smp.h
@@ -31,12 +31,16 @@
 
 struct pt_regs;
 
+extern cpumask_t cpu_present_mask;
+extern cpumask_t cpu_possible_map;
+extern cpumask_t cpu_online_map;
+extern cpumask_t cpu_callout_map;
+
 /*
  * Private routines/data
  */
  
 extern void smp_alloc_memory(void);
-extern cpumask_t cpu_online_map;
 extern volatile unsigned long smp_invalidate_needed;
 extern int pic_mode;
 extern int smp_num_siblings;
@@ -44,7 +48,6 @@
 extern void smp_message_irq(int cpl, void *dev_id, struct pt_regs *regs);
 extern void smp_send_reschedule(int cpu);
 extern void smp_invalidate_rcv(void);		/* Process an NMI */
-extern void (*mtrr_hook) (void);
 extern void zap_low_mappings(void);
 void smp_stop_cpu(void);
 extern cpumask_t cpu_sibling_map[NR_CPUS];
@@ -60,10 +63,6 @@
  * compresses data structures.
  */
 
-extern cpumask_t cpu_callout_map;
-extern cpumask_t cpu_callin_map;
-#define cpu_possible_map cpu_callout_map
-
 static inline int num_booting_cpus(void)
 {
 	return cpus_weight(cpu_callout_map);
@@ -77,7 +76,7 @@
 	return GET_APIC_ID(*(unsigned int *)(APIC_BASE+APIC_ID));
 }
 
-#define safe_smp_processor_id() (disable_apic ? 0 : x86_apicid_to_cpu(hard_smp_processor_id()))
+extern int safe_smp_processor_id(void);
 
 #endif /* !ASSEMBLY */
 
@@ -99,22 +98,6 @@
 	return cpus_addr(cpumask)[0];
 }
 
-static inline int x86_apicid_to_cpu(u8 apicid)
-{
-	int i;
-
-	for (i = 0; i < NR_CPUS; ++i)
-		if (x86_cpu_to_apicid[i] == apicid)
-			return i;
-
-	/* No entries in x86_cpu_to_apicid?  Either no MPS|ACPI,
-	 * or called too early.  Either way, we must be CPU 0. */
-      	if (x86_cpu_to_apicid[0] == BAD_APICID)
-		return 0;
-
-	return -1;
-}
-
 static inline int cpu_present_to_apicid(int mps_cpu)
 {
 	if (mps_cpu < NR_CPUS)