1 files changed, 233 insertions, 258 deletions

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 7d72c0d872b..547a48d78bd 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -21,7 +21,6 @@
  * 05/01/30 Suresh Siddha <suresh.b.siddha@intel.com>
  *						Setup cpu_sibling_map and cpu_core_map
  */
-#include <linux/config.h>
 
 #include <linux/module.h>
 #include <linux/acpi.h>
@@ -36,30 +35,29 @@
 #include <linux/mm.h>
 #include <linux/notifier.h>
 #include <linux/smp.h>
-#include <linux/smp_lock.h>
 #include <linux/spinlock.h>
 #include <linux/efi.h>
 #include <linux/percpu.h>
 #include <linux/bitops.h>
 
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 #include <asm/cache.h>
 #include <asm/current.h>
 #include <asm/delay.h>
-#include <asm/ia32.h>
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/machvec.h>
 #include <asm/mca.h>
 #include <asm/page.h>
+#include <asm/paravirt.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
 #include <asm/sal.h>
-#include <asm/system.h>
 #include <asm/tlbflush.h>
 #include <asm/unistd.h>
+#include <asm/sn/arch.h>
 
 #define SMP_DEBUG 0
 
@@ -70,12 +68,11 @@
 #endif
 
 #ifdef CONFIG_HOTPLUG_CPU
-/*
- * Store all idle threads, this can be reused instead of creating
- * a new thread. Also avoids complicated thread destroy functionality
- * for idle threads.
- */
-struct task_struct *idle_thread_array[NR_CPUS];
+#ifdef CONFIG_PERMIT_BSP_REMOVE
+#define bsp_remove_ok	1
+#else
+#define bsp_remove_ok	0
+#endif
 
 /*
  * Global array allocated for NR_CPUS at boot time
@@ -90,13 +87,7 @@ struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
 
 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
 
-#define get_idle_for_cpu(x)		(idle_thread_array[(x)])
-#define set_idle_for_cpu(x,p)	(idle_thread_array[(x)] = (p))
-
 #else
-
-#define get_idle_for_cpu(x)		(NULL)
-#define set_idle_for_cpu(x,p)
 #define set_brendez_area(x)
 #endif
 
@@ -104,7 +95,7 @@ struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
 /*
  * ITC synchronization related stuff:
  */
-#define MASTER	0
+#define MASTER	(0)
 #define SLAVE	(SMP_CACHE_BYTES/8)
 
 #define NUM_ROUNDS	64	/* magic value */
@@ -115,27 +106,22 @@ static volatile unsigned long go[SLAVE + 1];
 
 #define DEBUG_ITC_SYNC	0
 
-extern void __devinit calibrate_delay (void);
 extern void start_ap (void);
 extern unsigned long ia64_iobase;
 
-task_t *task_for_booting_cpu;
+struct task_struct *task_for_booting_cpu;
 
 /*
  * State for each CPU
  */
 DEFINE_PER_CPU(int, cpu_state);
 
-/* Bitmasks of currently online, and possible CPUs */
-cpumask_t cpu_online_map;
-EXPORT_SYMBOL(cpu_online_map);
-cpumask_t cpu_possible_map;
-EXPORT_SYMBOL(cpu_possible_map);
-
 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
-cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
+EXPORT_SYMBOL(cpu_core_map);
+DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
+EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
+
 int smp_num_siblings = 1;
-int smp_num_cpucores = 1;
 
 /* which logical CPU number maps to which CPU (physical APIC ID) */
 volatile int ia64_cpu_to_sapicid[NR_CPUS];
@@ -151,6 +137,27 @@ char __initdata no_int_routing;
 
 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
 
+#ifdef CONFIG_FORCE_CPEI_RETARGET
+#define CPEI_OVERRIDE_DEFAULT	(1)
+#else
+#define CPEI_OVERRIDE_DEFAULT	(0)
+#endif
+
+unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
+
+static int __init
+cmdl_force_cpei(char *str)
+{
+	int value=0;
+
+	get_option (&str, &value);
+	force_cpei_retarget = value;
+
+	return 1;
+}
+
+__setup("force_cpei=", cmdl_force_cpei);
+
 static int __init
 nointroute (char *str)
 {
@@ -161,6 +168,27 @@ nointroute (char *str)
 
 __setup("nointroute", nointroute);
 
+static void fix_b0_for_bsp(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	int cpuid;
+	static int fix_bsp_b0 = 1;
+
+	cpuid = smp_processor_id();
+
+	/*
+	 * Cache the b0 value on the first AP that comes up
+	 */
+	if (!(fix_bsp_b0 && cpuid))
+		return;
+
+	sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
+	printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
+
+	fix_bsp_b0 = 0;
+#endif
+}
+
 void
 sync_master (void *arg)
 {
@@ -270,7 +298,7 @@ ia64_sync_itc (unsigned int master)
 
 	go[MASTER] = 1;
 
-	if (smp_call_function_single(master, sync_master, NULL, 1, 0) < 0) {
+	if (smp_call_function_single(master, sync_master, NULL, 0) < 0) {
 		printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
 		return;
 	}
@@ -319,16 +347,17 @@ ia64_sync_itc (unsigned int master)
 /*
  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
  */
-static inline void __devinit
-smp_setup_percpu_timer (void)
+static inline void smp_setup_percpu_timer(void)
 {
 }
 
-static void __devinit
+static void
 smp_callin (void)
 {
-	int cpuid, phys_id;
+	int cpuid, phys_id, itc_master;
+	struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
 	extern void ia64_init_itm(void);
+	extern volatile int time_keeper_id;
 
 #ifdef CONFIG_PERFMON
 	extern void pfm_init_percpu(void);
@@ -336,6 +365,7 @@ smp_callin (void)
 
 	cpuid = smp_processor_id();
 	phys_id = hard_smp_processor_id();
+	itc_master = time_keeper_id;
 
 	if (cpu_online(cpuid)) {
 		printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
@@ -343,10 +373,21 @@ smp_callin (void)
 		BUG();
 	}
 
-	lock_ipi_calllock();
-	cpu_set(cpuid, cpu_online_map);
-	unlock_ipi_calllock();
+	fix_b0_for_bsp();
+
+	/*
+	 * numa_node_id() works after this.
+	 */
+	set_numa_node(cpu_to_node_map[cpuid]);
+	set_numa_mem(local_memory_node(cpu_to_node_map[cpuid]));
+
+	spin_lock(&vector_lock);
+	/* Setup the per cpu irq handling data structures */
+	__setup_vector_irq(cpuid);
+	notify_cpu_starting(cpuid);
+	set_cpu_online(cpuid, true);
 	per_cpu(cpu_state, cpuid) = CPU_ONLINE;
+	spin_unlock(&vector_lock);
 
 	smp_setup_percpu_timer();
 
@@ -365,20 +406,30 @@ smp_callin (void)
 		 * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
 		 * local_bh_enable(), which bugs out if irqs are not enabled...
 		 */
-		Dprintk("Going to syncup ITC with BP.\n");
-		ia64_sync_itc(0);
+		Dprintk("Going to syncup ITC with ITC Master.\n");
+		ia64_sync_itc(itc_master);
 	}
 
 	/*
 	 * Get our bogomips.
 	 */
 	ia64_init_itm();
-	calibrate_delay();
-	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 
-#ifdef CONFIG_IA32_SUPPORT
-	ia32_gdt_init();
-#endif
+	/*
+	 * Delay calibration can be skipped if new processor is identical to the
+	 * previous processor.
+	 */
+	last_cpuinfo = cpu_data(cpuid - 1);
+	this_cpuinfo = local_cpu_data;
+	if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
+	    last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
+	    last_cpuinfo->features != this_cpuinfo->features ||
+	    last_cpuinfo->revision != this_cpuinfo->revision ||
+	    last_cpuinfo->family != this_cpuinfo->family ||
+	    last_cpuinfo->archrev != this_cpuinfo->archrev ||
+	    last_cpuinfo->model != this_cpuinfo->model)
+		calibrate_delay();
+	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 
 	/*
 	 * Allow the master to continue.
@@ -391,74 +442,29 @@ smp_callin (void)
 /*
  * Activate a secondary processor.  head.S calls this.
  */
-int __devinit
+int
 start_secondary (void *unused)
 {
 	/* Early console may use I/O ports */
 	ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
+#ifndef CONFIG_PRINTK_TIME
 	Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
+#endif
 	efi_map_pal_code();
 	cpu_init();
+	preempt_disable();
 	smp_callin();
 
-	cpu_idle();
+	cpu_startup_entry(CPUHP_ONLINE);
 	return 0;
 }
 
-struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
-{
-	return NULL;
-}
-
-struct create_idle {
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-void
-do_fork_idle(void *_c_idle)
-{
-	struct create_idle *c_idle = _c_idle;
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
-static int __devinit
-do_boot_cpu (int sapicid, int cpu)
+static int
+do_boot_cpu (int sapicid, int cpu, struct task_struct *idle)
 {
 	int timeout;
-	struct create_idle c_idle = {
-		.cpu	= cpu,
-		.done	= COMPLETION_INITIALIZER(c_idle.done),
-	};
-	DECLARE_WORK(work, do_fork_idle, &c_idle);
-
- 	c_idle.idle = get_idle_for_cpu(cpu);
- 	if (c_idle.idle) {
-		init_idle(c_idle.idle, cpu);
- 		goto do_rest;
-	}
-
-	/*
-	 * We can't use kernel_thread since we must avoid to reschedule the child.
-	 */
-	if (!keventd_up() || current_is_keventd())
-		work.func(work.data);
-	else {
-		schedule_work(&work);
-		wait_for_completion(&c_idle.done);
-	}
-
-	if (IS_ERR(c_idle.idle))
-		panic("failed fork for CPU %d", cpu);
-
-	set_idle_for_cpu(cpu, c_idle.idle);
-
-do_rest:
-	task_for_booting_cpu = c_idle.idle;
 
+	task_for_booting_cpu = idle;
 	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
 
 	set_brendez_area(cpu);
@@ -478,7 +484,7 @@ do_rest:
 	if (!cpu_isset(cpu, cpu_callin_map)) {
 		printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
 		ia64_cpu_to_sapicid[cpu] = -1;
-		cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
+		set_cpu_online(cpu, false);  /* was set in smp_callin() */
 		return -EINVAL;
 	}
 	return 0;
@@ -505,21 +511,17 @@ smp_build_cpu_map (void)
 
 	for (cpu = 0; cpu < NR_CPUS; cpu++) {
 		ia64_cpu_to_sapicid[cpu] = -1;
-#ifdef CONFIG_HOTPLUG_CPU
-		cpu_set(cpu, cpu_possible_map);
-#endif
 	}
 
 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
-	cpus_clear(cpu_present_map);
-	cpu_set(0, cpu_present_map);
-	cpu_set(0, cpu_possible_map);
+	init_cpu_present(cpumask_of(0));
+	set_cpu_possible(0, true);
 	for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
 		sapicid = smp_boot_data.cpu_phys_id[i];
 		if (sapicid == boot_cpu_id)
 			continue;
-		cpu_set(cpu, cpu_present_map);
-		cpu_set(cpu, cpu_possible_map);
+		set_cpu_present(cpu, true);
+		set_cpu_possible(cpu, true);
 		ia64_cpu_to_sapicid[cpu] = sapicid;
 		cpu++;
 	}
@@ -539,10 +541,6 @@ smp_prepare_cpus (unsigned int max_cpus)
 
 	smp_setup_percpu_timer();
 
-	/*
-	 * We have the boot CPU online for sure.
-	 */
-	cpu_set(0, cpu_online_map);
 	cpu_set(0, cpu_callin_map);
 
 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
@@ -557,59 +555,34 @@ smp_prepare_cpus (unsigned int max_cpus)
 	 */
 	if (!max_cpus) {
 		printk(KERN_INFO "SMP mode deactivated.\n");
-		cpus_clear(cpu_online_map);
-		cpus_clear(cpu_present_map);
-		cpus_clear(cpu_possible_map);
-		cpu_set(0, cpu_online_map);
-		cpu_set(0, cpu_present_map);
-		cpu_set(0, cpu_possible_map);
+		init_cpu_online(cpumask_of(0));
+		init_cpu_present(cpumask_of(0));
+		init_cpu_possible(cpumask_of(0));
 		return;
 	}
 }
 
-void __devinit smp_prepare_boot_cpu(void)
+void smp_prepare_boot_cpu(void)
 {
-	cpu_set(smp_processor_id(), cpu_online_map);
+	set_cpu_online(smp_processor_id(), true);
 	cpu_set(smp_processor_id(), cpu_callin_map);
+	set_numa_node(cpu_to_node_map[smp_processor_id()]);
 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
+	paravirt_post_smp_prepare_boot_cpu();
 }
 
-/*
- * mt_info[] is a temporary store for all info returned by
- * PAL_LOGICAL_TO_PHYSICAL, to be copied into cpuinfo_ia64 when the
- * specific cpu comes.
- */
-static struct {
-	__u32   socket_id;
-	__u16   core_id;
-	__u16   thread_id;
-	__u16   proc_fixed_addr;
-	__u8    valid;
-} mt_info[NR_CPUS] __devinitdata;
-
 #ifdef CONFIG_HOTPLUG_CPU
 static inline void
-remove_from_mtinfo(int cpu)
-{
-	int i;
-
-	for_each_cpu(i)
-		if (mt_info[i].valid &&  mt_info[i].socket_id ==
-		    				cpu_data(cpu)->socket_id)
-			mt_info[i].valid = 0;
-}
-
-static inline void
 clear_cpu_sibling_map(int cpu)
 {
 	int i;
 
-	for_each_cpu_mask(i, cpu_sibling_map[cpu])
-		cpu_clear(cpu, cpu_sibling_map[i]);
+	for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu))
+		cpu_clear(cpu, per_cpu(cpu_sibling_map, i));
 	for_each_cpu_mask(i, cpu_core_map[cpu])
 		cpu_clear(cpu, cpu_core_map[i]);
 
-	cpu_sibling_map[cpu] = cpu_core_map[cpu] = CPU_MASK_NONE;
+	per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
 }
 
 static void
@@ -620,7 +593,7 @@ remove_siblinginfo(int cpu)
 	if (cpu_data(cpu)->threads_per_core == 1 &&
 	    cpu_data(cpu)->cores_per_socket == 1) {
 		cpu_clear(cpu, cpu_core_map[cpu]);
-		cpu_clear(cpu, cpu_sibling_map[cpu]);
+		cpu_clear(cpu, per_cpu(cpu_sibling_map, cpu));
 		return;
 	}
 
@@ -628,15 +601,50 @@ remove_siblinginfo(int cpu)
 
 	/* remove it from all sibling map's */
 	clear_cpu_sibling_map(cpu);
+}
+
+extern void fixup_irqs(void);
 
-	/* if this cpu is the last in the core group, remove all its info 
-	 * from mt_info structure
+int migrate_platform_irqs(unsigned int cpu)
+{
+	int new_cpei_cpu;
+	struct irq_data *data = NULL;
+	const struct cpumask *mask;
+	int 		retval = 0;
+
+	/*
+	 * dont permit CPEI target to removed.
 	 */
-	if (last)
-		remove_from_mtinfo(cpu);
+	if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
+		printk ("CPU (%d) is CPEI Target\n", cpu);
+		if (can_cpei_retarget()) {
+			/*
+			 * Now re-target the CPEI to a different processor
+			 */
+			new_cpei_cpu = cpumask_any(cpu_online_mask);
+			mask = cpumask_of(new_cpei_cpu);
+			set_cpei_target_cpu(new_cpei_cpu);
+			data = irq_get_irq_data(ia64_cpe_irq);
+			/*
+			 * Switch for now, immediately, we need to do fake intr
+			 * as other interrupts, but need to study CPEI behaviour with
+			 * polling before making changes.
+			 */
+			if (data && data->chip) {
+				data->chip->irq_disable(data);
+				data->chip->irq_set_affinity(data, mask, false);
+				data->chip->irq_enable(data);
+				printk ("Re-targeting CPEI to cpu %d\n", new_cpei_cpu);
+			}
+		}
+		if (!data) {
+			printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
+			retval = -EBUSY;
+		}
+	}
+	return retval;
 }
 
-extern void fixup_irqs(void);
 /* must be called with cpucontrol mutex held */
 int __cpu_disable(void)
 {
@@ -645,11 +653,24 @@ int __cpu_disable(void)
 	/*
 	 * dont permit boot processor for now
 	 */
-	if (cpu == 0)
+	if (cpu == 0 && !bsp_remove_ok) {
+		printk ("Your platform does not support removal of BSP\n");
+		return (-EBUSY);
+	}
+
+	if (ia64_platform_is("sn2")) {
+		if (!sn_cpu_disable_allowed(cpu))
+			return -EBUSY;
+	}
+
+	set_cpu_online(cpu, false);
+
+	if (migrate_platform_irqs(cpu)) {
+		set_cpu_online(cpu, true);
 		return -EBUSY;
+	}
 
 	remove_siblinginfo(cpu);
-	cpu_clear(cpu, cpu_online_map);
 	fixup_irqs();
 	local_flush_tlb_all();
 	cpu_clear(cpu, cpu_callin_map);
@@ -671,17 +692,6 @@ void __cpu_die(unsigned int cpu)
 	}
  	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
 }
-#else /* !CONFIG_HOTPLUG_CPU */
-int __cpu_disable(void)
-{
-	return -ENOSYS;
-}
-
-void __cpu_die(unsigned int cpu)
-{
-	/* We said "no" in __cpu_disable */
-	BUG();
-}
 #endif /* CONFIG_HOTPLUG_CPU */
 
 void
@@ -694,16 +704,15 @@ smp_cpus_done (unsigned int dummy)
 	 * Allow the user to impress friends.
 	 */
 
-	for (cpu = 0; cpu < NR_CPUS; cpu++)
-		if (cpu_online(cpu))
-			bogosum += cpu_data(cpu)->loops_per_jiffy;
+	for_each_online_cpu(cpu) {
+		bogosum += cpu_data(cpu)->loops_per_jiffy;
+	}
 
 	printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
 	       (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
 }
 
-static inline void __devinit
-set_cpu_sibling_map(int cpu)
+static inline void set_cpu_sibling_map(int cpu)
 {
 	int i;
 
@@ -712,15 +721,15 @@ set_cpu_sibling_map(int cpu)
 			cpu_set(i, cpu_core_map[cpu]);
 			cpu_set(cpu, cpu_core_map[i]);
 			if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
-				cpu_set(i, cpu_sibling_map[cpu]);
-				cpu_set(cpu, cpu_sibling_map[i]);
+				cpu_set(i, per_cpu(cpu_sibling_map, cpu));
+				cpu_set(cpu, per_cpu(cpu_sibling_map, i));
 			}
 		}
 	}
 }
 
-int __devinit
-__cpu_up (unsigned int cpu)
+int
+__cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int ret;
 	int sapicid;
@@ -738,13 +747,13 @@ __cpu_up (unsigned int cpu)
 
 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 	/* Processor goes to start_secondary(), sets online flag */
-	ret = do_boot_cpu(sapicid, cpu);
+	ret = do_boot_cpu(sapicid, cpu, tidle);
 	if (ret < 0)
 		return ret;
 
 	if (cpu_data(cpu)->threads_per_core == 1 &&
 	    cpu_data(cpu)->cores_per_socket == 1) {
-		cpu_set(cpu, cpu_sibling_map[cpu]);
+		cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
 		cpu_set(cpu, cpu_core_map[cpu]);
 		return 0;
 	}
@@ -755,7 +764,7 @@ __cpu_up (unsigned int cpu)
 }
 
 /*
- * Assume that CPU's have been discovered by some platform-dependent interface.  For
+ * Assume that CPUs have been discovered by some platform-dependent interface.  For
  * SoftSDV/Lion, that would be ACPI.
  *
  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
@@ -769,7 +778,7 @@ init_smp_config(void)
 	} *ap_startup;
 	long sal_ret;
 
-	/* Tell SAL where to drop the AP's.  */
+	/* Tell SAL where to drop the APs.  */
 	ap_startup = (struct fptr *) start_ap;
 	sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
 				       ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
@@ -778,106 +787,72 @@ init_smp_config(void)
 		       ia64_sal_strerror(sal_ret));
 }
 
-static inline int __devinit
-check_for_mtinfo_index(void)
-{
-	int i;
-	
-	for_each_cpu(i)
-		if (!mt_info[i].valid)
-			return i;
-
-	return -1;
-}
-
-/*
- * Search the mt_info to find out if this socket's cid/tid information is
- * cached or not. If the socket exists, fill in the core_id and thread_id 
- * in cpuinfo
- */
-static int __devinit
-check_for_new_socket(__u16 logical_address, struct cpuinfo_ia64 *c)
-{
-	int i;
-	__u32 sid = c->socket_id;
-
-	for_each_cpu(i) {
-		if (mt_info[i].valid && mt_info[i].proc_fixed_addr == logical_address
-		    && mt_info[i].socket_id == sid) {
-			c->core_id = mt_info[i].core_id;
-			c->thread_id = mt_info[i].thread_id;
-			return 1; /* not a new socket */
-		}
-	}
-	return 0;
-}
-
 /*
  * identify_siblings(cpu) gets called from identify_cpu. This populates the 
  * information related to logical execution units in per_cpu_data structure.
  */
-void __devinit
-identify_siblings(struct cpuinfo_ia64 *c)
+void identify_siblings(struct cpuinfo_ia64 *c)
 {
-	s64 status;
+	long status;
 	u16 pltid;
-	u64 proc_fixed_addr;
-	int count, i;
 	pal_logical_to_physical_t info;
 
-	if (smp_num_cpucores == 1 && smp_num_siblings == 1)
-		return;
+	status = ia64_pal_logical_to_phys(-1, &info);
+	if (status != PAL_STATUS_SUCCESS) {
+		if (status != PAL_STATUS_UNIMPLEMENTED) {
+			printk(KERN_ERR
+				"ia64_pal_logical_to_phys failed with %ld\n",
+				status);
+			return;
+		}
 
-	if ((status = ia64_pal_logical_to_phys(0, &info)) != PAL_STATUS_SUCCESS) {
-		printk(KERN_ERR "ia64_pal_logical_to_phys failed with %ld\n",
-		       status);
-		return;
-	}
-	if ((status = ia64_sal_physical_id_info(&pltid)) != PAL_STATUS_SUCCESS) {
-		printk(KERN_ERR "ia64_sal_pltid failed with %ld\n", status);
-		return;
+		info.overview_ppid = 0;
+		info.overview_cpp  = 1;
+		info.overview_tpc  = 1;
 	}
-	if ((status = ia64_pal_fixed_addr(&proc_fixed_addr)) != PAL_STATUS_SUCCESS) {
-		printk(KERN_ERR "ia64_pal_fixed_addr failed with %ld\n", status);
+
+	status = ia64_sal_physical_id_info(&pltid);
+	if (status != PAL_STATUS_SUCCESS) {
+		if (status != PAL_STATUS_UNIMPLEMENTED)
+			printk(KERN_ERR
+				"ia64_sal_pltid failed with %ld\n",
+				status);
 		return;
 	}
 
 	c->socket_id =  (pltid << 8) | info.overview_ppid;
-	c->cores_per_socket = info.overview_cpp;
-	c->threads_per_core = info.overview_tpc;
-	count = c->num_log = info.overview_num_log;
 
-	/* If the thread and core id information is already cached, then
-	 * we will simply update cpu_info and return. Otherwise, we will
-	 * do the PAL calls and cache core and thread id's of all the siblings.
-	 */
-	if (check_for_new_socket(proc_fixed_addr, c))
+	if (info.overview_cpp == 1 && info.overview_tpc == 1)
 		return;
 
-	for (i = 0; i < count; i++) {
-		int index;
-
-		if (i && (status = ia64_pal_logical_to_phys(i, &info))
-			  != PAL_STATUS_SUCCESS) {
-                	printk(KERN_ERR "ia64_pal_logical_to_phys failed"
-					" with %ld\n", status);
-                	return;
-		}
-		if (info.log2_la == proc_fixed_addr) {
-			c->core_id = info.log1_cid;
-			c->thread_id = info.log1_tid;
-		}
+	c->cores_per_socket = info.overview_cpp;
+	c->threads_per_core = info.overview_tpc;
+	c->num_log = info.overview_num_log;
 
-		index = check_for_mtinfo_index();
-		/* We will not do the mt_info caching optimization in this case.
-		 */
-		if (index < 0)
-			continue;
+	c->core_id = info.log1_cid;
+	c->thread_id = info.log1_tid;
+}
 
-		mt_info[index].valid = 1;
-		mt_info[index].socket_id = c->socket_id;
-		mt_info[index].core_id = info.log1_cid;
-		mt_info[index].thread_id = info.log1_tid;
-		mt_info[index].proc_fixed_addr = info.log2_la;
+/*
+ * returns non zero, if multi-threading is enabled
+ * on at least one physical package. Due to hotplug cpu
+ * and (maxcpus=), all threads may not necessarily be enabled
+ * even though the processor supports multi-threading.
+ */
+int is_multithreading_enabled(void)
+{
+	int i, j;
+
+	for_each_present_cpu(i) {
+		for_each_present_cpu(j) {
+			if (j == i)
+				continue;
+			if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
+				if (cpu_data(j)->core_id == cpu_data(i)->core_id)
+					return 1;
+			}
+		}
 	}
+	return 0;
 }
+EXPORT_SYMBOL_GPL(is_multithreading_enabled);