diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 3ab9bdd..a9371c9 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -288,6 +288,7 @@
 
 	int (*probe)(void);
 	int (*acpi_madt_oem_check)(char *oem_id, char *oem_table_id);
+	int (*apic_id_valid)(int apicid);
 	int (*apic_id_registered)(void);
 
 	u32 irq_delivery_mode;
@@ -532,6 +533,11 @@
 	return apic->get_apic_id(reg);
 }
 
+static inline int default_apic_id_valid(int apicid)
+{
+	return x2apic_mode || (apicid < 255);
+}
+
 extern void default_setup_apic_routing(void);
 
 extern struct apic apic_noop;
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
index 8c3cdde..359b689 100644
--- a/arch/x86/kernel/apic/apic_flat_64.c
+++ b/arch/x86/kernel/apic/apic_flat_64.c
@@ -180,6 +180,7 @@
 	.name				= "flat",
 	.probe				= flat_probe,
 	.acpi_madt_oem_check		= flat_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= flat_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
@@ -337,6 +338,7 @@
 	.name				= "physical flat",
 	.probe				= physflat_probe,
 	.acpi_madt_oem_check		= physflat_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= flat_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c
index 775b82b..634ae6c 100644
--- a/arch/x86/kernel/apic/apic_noop.c
+++ b/arch/x86/kernel/apic/apic_noop.c
@@ -124,6 +124,7 @@
 	.probe				= noop_probe,
 	.acpi_madt_oem_check		= NULL,
 
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= noop_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
index 09d3d8c..d9ea5f3 100644
--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -56,6 +56,12 @@
 	return get_apic_id(apic_read(APIC_ID));
 }
 
+static int numachip_apic_id_valid(int apicid)
+{
+	/* Trust what bootloader passes in MADT */
+	return 1;
+}
+
 static int numachip_apic_id_registered(void)
 {
 	return physid_isset(read_xapic_id(), phys_cpu_present_map);
@@ -223,10 +229,11 @@
 }
 early_initcall(numachip_system_init);
 
-static int numachip_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
+static int __cpuinit numachip_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
 	if (!strncmp(oem_id, "NUMASC", 6)) {
 		numachip_system = 1;
+		setup_force_cpu_cap(X86_FEATURE_X2APIC);
 		return 1;
 	}
 
@@ -238,6 +245,7 @@
 	.name				= "NumaConnect system",
 	.probe				= numachip_probe,
 	.acpi_madt_oem_check		= numachip_acpi_madt_oem_check,
+	.apic_id_valid			= numachip_apic_id_valid,
 	.apic_id_registered		= numachip_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/apic/bigsmp_32.c b/arch/x86/kernel/apic/bigsmp_32.c
index 521bead..0cdec70 100644
--- a/arch/x86/kernel/apic/bigsmp_32.c
+++ b/arch/x86/kernel/apic/bigsmp_32.c
@@ -198,6 +198,7 @@
 	.name				= "bigsmp",
 	.probe				= probe_bigsmp,
 	.acpi_madt_oem_check		= NULL,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= bigsmp_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/apic/es7000_32.c b/arch/x86/kernel/apic/es7000_32.c
index 5d513bc..e42d1d3b9 100644
--- a/arch/x86/kernel/apic/es7000_32.c
+++ b/arch/x86/kernel/apic/es7000_32.c
@@ -625,6 +625,7 @@
 	.name				= "es7000",
 	.probe				= probe_es7000,
 	.acpi_madt_oem_check		= es7000_acpi_madt_oem_check_cluster,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= es7000_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
@@ -690,6 +691,7 @@
 	.name				= "es7000",
 	.probe				= probe_es7000,
 	.acpi_madt_oem_check		= es7000_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= es7000_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/apic/numaq_32.c b/arch/x86/kernel/apic/numaq_32.c
index c4a61ca..00d2422 100644
--- a/arch/x86/kernel/apic/numaq_32.c
+++ b/arch/x86/kernel/apic/numaq_32.c
@@ -478,6 +478,7 @@
 	.name				= "NUMAQ",
 	.probe				= probe_numaq,
 	.acpi_madt_oem_check		= NULL,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= numaq_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
diff --git a/arch/x86/kernel/apic/probe_32.c b/arch/x86/kernel/apic/probe_32.c
index 0787bb3..ff2c1b9 100644
--- a/arch/x86/kernel/apic/probe_32.c
+++ b/arch/x86/kernel/apic/probe_32.c
@@ -92,6 +92,7 @@
 	.name				= "default",
 	.probe				= probe_default,
 	.acpi_madt_oem_check		= NULL,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= default_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
diff --git a/arch/x86/kernel/apic/summit_32.c b/arch/x86/kernel/apic/summit_32.c
index 1911442..fea000b 100644
--- a/arch/x86/kernel/apic/summit_32.c
+++ b/arch/x86/kernel/apic/summit_32.c
@@ -496,6 +496,7 @@
 	.name				= "summit",
 	.probe				= probe_summit,
 	.acpi_madt_oem_check		= summit_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= summit_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index 5007958..9193713 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -213,6 +213,7 @@
 	.name				= "cluster x2apic",
 	.probe				= x2apic_cluster_probe,
 	.acpi_madt_oem_check		= x2apic_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= x2apic_apic_id_registered,
 
 	.irq_delivery_mode		= dest_LowestPrio,
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index f5373df..bcd1db6 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -119,6 +119,7 @@
 	.name				= "physical x2apic",
 	.probe				= x2apic_phys_probe,
 	.acpi_madt_oem_check		= x2apic_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= x2apic_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 79b05b8..fc47714 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -351,6 +351,7 @@
 	.name				= "UV large system",
 	.probe				= uv_probe,
 	.acpi_madt_oem_check		= uv_acpi_madt_oem_check,
+	.apic_id_valid			= default_apic_id_valid,
 	.apic_id_registered		= uv_apic_id_registered,
 
 	.irq_delivery_mode		= dest_Fixed,
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 66d250c..d279e6e 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -847,7 +847,7 @@
 
 	if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
 	    !physid_isset(apicid, phys_cpu_present_map) ||
-	    (!x2apic_mode && apicid >= 255)) {
+	    !apic->apic_id_valid(apicid)) {
 		printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
 		return -EINVAL;
 	}