[PATCH] x86-64: add genapic_force

Add genapic_force. Used by the next Intel quirks patch.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Li, Shaohua" <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

arch/x86_64/kernel/genapic.c

@@ -33,7 +33,7 @@ extern struct genapic apic_flat;
 extern struct genapic apic_physflat;
 
 struct genapic *genapic = &apic_flat;
-
+struct genapic *genapic_force;
 
 /*
  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
@@ -46,6 +46,13 @@ void __init clustered_apic_check(void)
 	u8 cluster_cnt[NUM_APIC_CLUSTERS];
 	int max_apic = 0;
 
+	/* genapic selection can be forced because of certain quirks.
+	 */
+	if (genapic_force) {
+		genapic = genapic_force;
+		goto print;
+	}
+
 #if defined(CONFIG_ACPI)
 	/*
 	 * Some x86_64 machines use physical APIC mode regardless of how many

include/asm-x86_64/genapic.h

@@ -30,6 +30,6 @@ struct genapic {
 };
 
 
-extern struct genapic *genapic;
+extern struct genapic *genapic, *genapic_force, apic_flat;
 
 #endif