x86, x2apic: Simplify apic init in SMP and UP builds

Move enable_IR_x2apic() inside the default_setup_apic_routing(),
and for SMP platforms, move the default_setup_apic_routing() after
smp_sanity_check(). This cleans up the code that tries to avoid multiple
calls to default_setup_apic_routing() when smp_sanity_check() fails (which
goes through the APIC_init_uniprocessor() path).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100827181049.173087246@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/apic/apic.c

@@ -1665,10 +1665,7 @@ int __init APIC_init_uniprocessor(void)
 	}
 #endif
 
-#ifndef CONFIG_SMP
-	enable_IR_x2apic();
 	default_setup_apic_routing();
-#endif
 
 	verify_local_APIC();
 	connect_bsp_APIC();

arch/x86/kernel/apic/probe_64.c

@@ -54,6 +54,9 @@ static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
  */
 void __init default_setup_apic_routing(void)
 {
+
+	enable_IR_x2apic();
+
 #ifdef CONFIG_X86_X2APIC
 	if (x2apic_mode
 #ifdef CONFIG_X86_UV

arch/x86/kernel/smpboot.c

@@ -1109,15 +1109,15 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	}
 	set_cpu_sibling_map(0);
 
-	enable_IR_x2apic();
-	default_setup_apic_routing();
 
 	if (smp_sanity_check(max_cpus) < 0) {
 		printk(KERN_INFO "SMP disabled\n");
 		disable_smp();
 		goto out;
 	}
 
+	default_setup_apic_routing();
+
 	preempt_disable();
 	if (read_apic_id() != boot_cpu_physical_apicid) {
 		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",