[PATCH] x86: hot plug CPU to support physical add of new processors

The patch allows physical bring-up of new processors (not initially present
in the configuration) from facilities such as driver/utility implemented on
a platform.  The actual method of making processors available is up to the
platform implementation.
Signed-off-by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Zwane Mwaikambo <zwane@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/irq.c

@@ -218,7 +218,7 @@ int show_interrupts(struct seq_file *p, void *v)
 
 	if (i == 0) {
 		seq_printf(p, "           ");
-		for_each_cpu(j)
+		for_each_online_cpu(j)
 			seq_printf(p, "CPU%d       ",j);
 		seq_putc(p, '\n');
 	}
@@ -232,7 +232,7 @@ int show_interrupts(struct seq_file *p, void *v)
 #ifndef CONFIG_SMP
 		seq_printf(p, "%10u ", kstat_irqs(i));
 #else
-		for_each_cpu(j)
+		for_each_online_cpu(j)
 			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
 		seq_printf(p, " %14s", irq_desc[i].handler->typename);
@@ -246,12 +246,12 @@ skip:
 		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 	} else if (i == NR_IRQS) {
 		seq_printf(p, "NMI: ");
-		for_each_cpu(j)
+		for_each_online_cpu(j)
 			seq_printf(p, "%10u ", nmi_count(j));
 		seq_putc(p, '\n');
 #ifdef CONFIG_X86_LOCAL_APIC
 		seq_printf(p, "LOC: ");
-		for_each_cpu(j)
+		for_each_online_cpu(j)
 			seq_printf(p, "%10u ",
 				per_cpu(irq_stat,j).apic_timer_irqs);
 		seq_putc(p, '\n');

arch/i386/kernel/mpparse.c

@@ -69,7 +69,7 @@ unsigned int def_to_bigsmp = 0;
 /* Processor that is doing the boot up */
 unsigned int boot_cpu_physical_apicid = -1U;
 /* Internal processor count */
-static unsigned int __initdata num_processors;
+static unsigned int __devinitdata num_processors;
 
 /* Bitmask of physically existing CPUs */
 physid_mask_t phys_cpu_present_map;
@@ -119,7 +119,7 @@ static int MP_valid_apicid(int apicid, int version)
 }
 #endif
 
-static void __init MP_processor_info (struct mpc_config_processor *m)
+static void __devinit MP_processor_info (struct mpc_config_processor *m)
 {
  	int ver, apicid;
 	physid_mask_t phys_cpu;
@@ -834,7 +834,7 @@ void __init mp_register_lapic_address (
 }
 
 
-void __init mp_register_lapic (
+void __devinit mp_register_lapic (
 	u8			id, 
 	u8			enabled)
 {

arch/i386/kernel/smpboot.c

@@ -87,7 +87,11 @@ EXPORT_SYMBOL(cpu_online_map);
 cpumask_t cpu_callin_map;
 cpumask_t cpu_callout_map;
 EXPORT_SYMBOL(cpu_callout_map);
+#ifdef CONFIG_HOTPLUG_CPU
+cpumask_t cpu_possible_map = CPU_MASK_ALL;
+#else
 cpumask_t cpu_possible_map;
+#endif
 EXPORT_SYMBOL(cpu_possible_map);
 static cpumask_t smp_commenced_mask;