1 files changed, 70 insertions, 2 deletions

diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index b2617993de19..4b2bb1381ffa 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -11,6 +11,7 @@
 #include <asm/ipi.h>
 
 static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
+static DEFINE_PER_CPU(cpumask_var_t, cpus_in_cluster);
 
 static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
@@ -48,6 +49,11 @@ static void
         native_x2apic_icr_write(cfg, apicid);
 }
 
+static inline u32 x2apic_cluster(int cpu)
+{
+        return per_cpu(x86_cpu_to_logical_apicid, cpu) >> 16;
+}
+
 /*
  * for now, we send the IPI's one by one in the cpumask.
  * TBD: Based on the cpu mask, we can send the IPI's to the cluster group
@@ -163,14 +169,76 @@ static void x2apic_send_IPI_self(int vector)
 
 static void init_x2apic_ldr(void)
 {
+        unsigned int this_cpu = smp_processor_id();
+        unsigned int cpu;
+
+        per_cpu(x86_cpu_to_logical_apicid, this_cpu) = apic_read(APIC_LDR);
+
+        __cpu_set(this_cpu, per_cpu(cpus_in_cluster, this_cpu));
+        for_each_online_cpu(cpu) {
+                if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))
+                        continue;
+                __cpu_set(this_cpu, per_cpu(cpus_in_cluster, cpu));
+                __cpu_set(cpu, per_cpu(cpus_in_cluster, this_cpu));
+        }
+}
+
+ /*
+  * At CPU state changes, update the x2apic cluster sibling info.
+  */
+static int __cpuinit
+update_clusterinfo(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+        unsigned int this_cpu = (unsigned long)hcpu;
+        unsigned int cpu;
+        int err = 0;
+
+        switch (action) {
+        case CPU_UP_PREPARE:
+                if (!zalloc_cpumask_var(&per_cpu(cpus_in_cluster, this_cpu),
+                                        GFP_KERNEL)) {
+                        err = -ENOMEM;
+                }
+                break;
+        case CPU_UP_CANCELED:
+        case CPU_UP_CANCELED_FROZEN:
+        case CPU_DEAD:
+                for_each_online_cpu(cpu) {
+                        if (x2apic_cluster(this_cpu) != x2apic_cluster(cpu))
+                                continue;
+                        __cpu_clear(this_cpu, per_cpu(cpus_in_cluster, cpu));
+                        __cpu_clear(cpu, per_cpu(cpus_in_cluster, this_cpu));
+                }
+                free_cpumask_var(per_cpu(cpus_in_cluster, this_cpu));
+                break;
+        }
+
+        return notifier_from_errno(err);
+}
+
+static struct notifier_block __refdata x2apic_cpu_notifier = {
+        .notifier_call = update_clusterinfo,
+};
+
+static int x2apic_init_cpu_notifier(void)
+{
         int cpu = smp_processor_id();
 
-        per_cpu(x86_cpu_to_logical_apicid, cpu) = apic_read(APIC_LDR);
+        zalloc_cpumask_var(&per_cpu(cpus_in_cluster, cpu), GFP_KERNEL);
+
+        BUG_ON(!per_cpu(cpus_in_cluster, cpu));
+
+        __cpu_set(cpu, per_cpu(cpus_in_cluster, cpu));
+        register_hotcpu_notifier(&x2apic_cpu_notifier);
+        return 1;
 }
 
 static int x2apic_cluster_probe(void)
 {
-        return x2apic_mode;
+        if (x2apic_mode)
+                return x2apic_init_cpu_notifier();
+        else
+                return 0;
 }
 
 struct apic apic_x2apic_cluster = {