x86: add apic probe for genapic 64bit - fix

intr_remapping_enabled get assigned later, so need to check that
in setup_apic_routing

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/genapic_64.c

@@ -16,6 +16,7 @@
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/hardirq.h>
+#include <linux/dmar.h>
 
 #include <asm/smp.h>
 #include <asm/ipi.h>
@@ -42,6 +43,11 @@ static struct genapic *apic_probe[] __initdata = {
  */
 void __init setup_apic_routing(void)
 {
+	if (genapic == &apic_x2apic_phys || genapic == &apic_x2apic_cluster) {
+		if (!intr_remapping_enabled)
+			genapic = &apic_flat;
+	}
+
 	if (genapic == &apic_flat) {
 		if (max_physical_apicid >= 8)
 			genapic = &apic_physflat;

arch/x86/kernel/genx2apic_cluster.c

@@ -14,7 +14,7 @@ DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
 
 static int __init x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
-	if (cpu_has_x2apic && intr_remapping_enabled)
+	if (cpu_has_x2apic)
 		return 1;
 
 	return 0;

arch/x86/kernel/genx2apic_phys.c

@@ -21,7 +21,7 @@ early_param("x2apic_phys", set_x2apic_phys_mode);
 
 static int __init x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
-	if (cpu_has_x2apic && intr_remapping_enabled && x2apic_phys)
+	if (cpu_has_x2apic && x2apic_phys)
 		return 1;
 
 	return 0;