diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index e26447aa469e9..b7ffae46101da 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1734,6 +1734,8 @@ void apic_ap_setup(void)
 	end_local_APIC_setup();
 }
 
+static __init void cpu_set_boot_apic(void);
+
 static __init void apic_read_boot_cpu_id(bool x2apic)
 {
 	/*
@@ -1748,9 +1750,9 @@ static __init void apic_read_boot_cpu_id(bool x2apic)
 		boot_cpu_physical_apicid = read_apic_id();
 		boot_cpu_apic_version = GET_APIC_VERSION(apic_read(APIC_LVR));
 	}
+	cpu_set_boot_apic();
 }
 
-
 #ifdef CONFIG_X86_X2APIC
 int x2apic_mode;
 EXPORT_SYMBOL_GPL(x2apic_mode);
@@ -2426,76 +2428,8 @@ static int allocate_logical_cpuid(int apicid)
 	return nr_logical_cpuids++;
 }
 
-int generic_processor_info(int apicid, int version)
+static void cpu_update_apic(int cpu, int apicid, int version)
 {
-	int cpu, max = nr_cpu_ids;
-	bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
-				phys_cpu_present_map);
-
-	/*
-	 * boot_cpu_physical_apicid is guaranteed to contain the boot CPU
-	 * APIC ID read from the local APIC when this function is invoked.
-	 */
-	if (disabled_cpu_apicid != boot_cpu_physical_apicid &&
-	    disabled_cpu_apicid == apicid) {
-		int thiscpu = num_processors + disabled_cpus;
-
-		pr_warn("APIC: Disabling requested cpu. Processor %d/0x%x ignored.\n",
-			thiscpu, apicid);
-
-		disabled_cpus++;
-		return -ENODEV;
-	}
-
-	/*
-	 * If boot cpu has not been detected yet, then only allow upto
-	 * nr_cpu_ids - 1 processors and keep one slot free for boot cpu
-	 */
-	if (!boot_cpu_detected && num_processors >= nr_cpu_ids - 1 &&
-	    apicid != boot_cpu_physical_apicid) {
-		int thiscpu = max + disabled_cpus - 1;
-
-		pr_warn("APIC: NR_CPUS/possible_cpus limit of %i almost"
-			" reached. Keeping one slot for boot cpu."
-			"  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
-
-		disabled_cpus++;
-		return -ENODEV;
-	}
-
-	if (num_processors >= nr_cpu_ids) {
-		int thiscpu = max + disabled_cpus;
-
-		pr_warn("APIC: NR_CPUS/possible_cpus limit of %i reached. "
-			"Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
-
-		disabled_cpus++;
-		return -EINVAL;
-	}
-
-	if (apicid == boot_cpu_physical_apicid) {
-		/*
-		 * x86_cpu_to_apicid is required to have processors listed
-		 * in same order as logical cpu numbers. Hence the first
-		 * entry is BSP, and so on.
-		 * boot_cpu_init() already hold bit 0 in cpu_present_mask
-		 * for BSP.
-		 */
-		cpu = 0;
-
-		/* Logical cpuid 0 is reserved for BSP. */
-		cpuid_to_apicid[0] = apicid;
-	} else {
-		cpu = allocate_logical_cpuid(apicid);
-		if (cpu < 0) {
-			disabled_cpus++;
-			return -EINVAL;
-		}
-	}
-
-	/*
-	 * Validate version
-	 */
 	if (version == 0x0) {
 		pr_warn("BIOS bug: APIC version is 0 for CPU %d/0x%x, fixing up to 0x10\n",
 			cpu, apicid);
@@ -2521,10 +2455,56 @@ int generic_processor_info(int apicid, int version)
 
 	if (system_state != SYSTEM_BOOTING)
 		cpu_mark_primary_thread(cpu, apicid);
+}
+
+static __init void cpu_set_boot_apic(void)
+{
+	cpuid_to_apicid[0] = boot_cpu_physical_apicid;
+	cpu_update_apic(0, boot_cpu_physical_apicid, boot_cpu_apic_version);
+}
+
+int generic_processor_info(int apicid, int version)
+{
+	int cpu, max = nr_cpu_ids;
+
+	/* The boot CPU must be set before MADT/MPTABLE parsing happens */
+	if (cpuid_to_apicid[0] == BAD_APICID)
+		panic("Boot CPU APIC not registered yet\n");
+
+	if (apicid == boot_cpu_physical_apicid)
+		return 0;
+
+	if (disabled_cpu_apicid == apicid) {
+		int thiscpu = num_processors + disabled_cpus;
+
+		pr_warn("APIC: Disabling requested cpu. Processor %d/0x%x ignored.\n",
+			thiscpu, apicid);
 
+		disabled_cpus++;
+		return -ENODEV;
+	}
+
+	if (num_processors >= nr_cpu_ids) {
+		int thiscpu = max + disabled_cpus;
+
+		pr_warn("APIC: NR_CPUS/possible_cpus limit of %i reached. "
+			"Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
+
+		disabled_cpus++;
+		return -EINVAL;
+	}
+
+	cpu = allocate_logical_cpuid(apicid);
+	if (cpu < 0) {
+		disabled_cpus++;
+		return -EINVAL;
+	}
+
+	cpu_update_apic(cpu, apicid, version);
 	return cpu;
 }
 
+
 void __irq_msi_compose_msg(struct irq_cfg *cfg, struct msi_msg *msg,
 			   bool dmar)
 {