2 files changed, 18 insertions, 57 deletions

diff --git a/arch/x86_64/kernel/genapic.c b/arch/x86_64/kernel/genapic.c
index 2f2b8fc6e2f3..025f26ebb8d7 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 a0e9a4b93484..d7e516ccbaa4 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