diff --git a/arch/x86_64/kernel/genapic.c b/arch/x86_64/kernel/genapic.c
index 2f2b8fc6e2f3510211c7e5c5b94b08c93234ef0e..025f26ebb8d705d769b8a125ecbb7eb83d458c9b 100644
--- a/arch/x86_64/kernel/genapic.c
+++ b/arch/x86_64/kernel/genapic.c
@@ -11,26 +11,24 @@
 #include <linux/threads.h>
 #include <linux/cpumask.h>
 #include <linux/string.h>
+#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/ctype.h>
 #include <linux/init.h>
-#include <linux/module.h>
 
 #include <asm/smp.h>
 #include <asm/ipi.h>
 
-#if defined(CONFIG_ACPI)
+#ifdef CONFIG_ACPI
 #include <acpi/acpi_bus.h>
 #endif
 
 /* which logical CPU number maps to which CPU (physical APIC ID) */
-u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly
+					= { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(x86_cpu_to_apicid);
-u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
 
-extern struct genapic apic_cluster;
-extern struct genapic apic_flat;
-extern struct genapic apic_physflat;
+u8 x86_cpu_to_log_apicid[NR_CPUS]	= { [0 ... NR_CPUS-1] = BAD_APICID };
 
 struct genapic __read_mostly *genapic = &apic_flat;
 
@@ -39,76 +37,37 @@ struct genapic __read_mostly *genapic = &apic_flat;
  */
 void __init clustered_apic_check(void)
 {
-	int i;
-	u8 clusters, max_cluster;
+	unsigned int i, max_apic = 0;
 	u8 id;
-	u8 cluster_cnt[NUM_APIC_CLUSTERS];
-	int max_apic = 0;
 
 #ifdef CONFIG_ACPI
 	/*
-	 * Some x86_64 machines use physical APIC mode regardless of how many
-	 * procs/clusters are present (x86_64 ES7000 is an example).
+	 * Quirk: some x86_64 machines can only use physical APIC mode
+	 * regardless of how many processors are present (x86_64 ES7000
+	 * is an example).
 	 */
-	if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID)
-		if (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) {
-			genapic = &apic_cluster;
-			goto print;
-		}
+	if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
+			(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
+		genapic = &apic_physflat;
 #endif
 
-	memset(cluster_cnt, 0, sizeof(cluster_cnt));
 	for (i = 0; i < NR_CPUS; i++) {
 		id = bios_cpu_apicid[i];
 		if (id == BAD_APICID)
 			continue;
 		if (id > max_apic)
 			max_apic = id;
-		cluster_cnt[APIC_CLUSTERID(id)]++;
 	}
 
-	/*
-	 * Don't use clustered mode on AMD platforms, default
-	 * to flat logical mode.
-	 */
- 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
-		/*
-		 * Switch to physical flat mode if more than 8 APICs
-		 * (In the case of 8 CPUs APIC ID goes from 0 to 7):
-		 */
-		if (max_apic >= 8)
-			genapic = &apic_physflat;
- 		goto print;
- 	}
-
-	clusters = 0;
-	max_cluster = 0;
-
-	for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
-		if (cluster_cnt[i] > 0) {
-			++clusters;
-			if (cluster_cnt[i] > max_cluster)
-				max_cluster = cluster_cnt[i];
-		}
-	}
-
-	/*
-	 * If we have clusters <= 1 and CPUs <= 8 in cluster 0, then flat mode,
-	 * else if max_cluster <= 4 and cluster_cnt[15] == 0, clustered logical
-	 * else physical mode.
-	 * (We don't use lowest priority delivery + HW APIC IRQ steering, so
-	 * can ignore the clustered logical case and go straight to physical.)
-	 */
-	if (clusters <= 1 && max_cluster <= 8 && cluster_cnt[0] == max_cluster)
+	if (max_apic < 8)
 		genapic = &apic_flat;
 	else
-		genapic = &apic_cluster;
+		genapic = &apic_physflat;
 
-print:
 	printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
 }
 
-/* Same for both flat and clustered. */
+/* Same for both flat and physical. */
 
 void send_IPI_self(int vector)
 {
diff --git a/include/asm-x86_64/genapic.h b/include/asm-x86_64/genapic.h
index a0e9a4b934844a96c4dced8b8cdd293e2b5decfb..d7e516ccbaa4d3ae54f8957750358c07ccd366d4 100644
--- a/include/asm-x86_64/genapic.h
+++ b/include/asm-x86_64/genapic.h
@@ -29,7 +29,9 @@ struct genapic {
 	unsigned int (*phys_pkg_id)(int index_msb);
 };
 
-
 extern struct genapic *genapic;
 
+extern struct genapic apic_flat;
+extern struct genapic apic_physflat;
+
 #endif