diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index d0a21b12dd585c5e73c1930f4afa37aee5a483c6..a7f36ab1c07d484b0061099db52003207427697f 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -5,6 +5,7 @@
 #include <asm/ldt.h>
 #include <asm/mmu.h>
 #include <asm/fixmap.h>
+#include <asm/irq_vectors.h>
 
 #include <linux/smp.h>
 #include <linux/percpu.h>
@@ -482,16 +483,14 @@ static inline void _set_gate(int gate, unsigned type, void *addr,
 				0, 0, __KERNEL_CS);			\
 	} while (0)
 
-extern int first_system_vector;
 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 extern unsigned long used_vectors[];
 
 static inline void alloc_system_vector(int vector)
 {
+	BUG_ON(vector < FIRST_SYSTEM_VECTOR);
 	if (!test_bit(vector, used_vectors)) {
 		set_bit(vector, used_vectors);
-		if (first_system_vector > vector)
-			first_system_vector = vector;
 	} else {
 		BUG();
 	}
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 98b3dd8cf2bf4331f360f06b7501f03d397ceac2..8996ef1eb39fad884bdc1667df83d76e419fa0f0 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -177,8 +177,6 @@ static int disable_apic_timer __initdata;
 int local_apic_timer_c2_ok;
 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
 
-int first_system_vector = FIRST_SYSTEM_VECTOR;
-
 /*
  * Debug level, exported for io_apic.c
  */
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index b3af457ed667563091898d2ce95aef29290904ad..88c214e75a6be0bd26a126e2f57ad67d46a444fe 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -166,7 +166,7 @@ static int __assign_irq_vector(int irq, struct apic_chip_data *d,
 		offset = current_offset;
 next:
 		vector += 16;
-		if (vector >= first_system_vector) {
+		if (vector >= FIRST_SYSTEM_VECTOR) {
 			offset = (offset + 1) % 16;
 			vector = FIRST_EXTERNAL_VECTOR + offset;
 		}
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index e6073a0ce77eb690bb5fbba4ed8acf913f58fe38..019d0ac8ed3ad92af7a058d8a55c73299eec02fc 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -429,7 +429,7 @@ int check_irq_vectors_for_cpu_disable(void)
 		 * this w/o holding vector_lock.
 		 */
 		for (vector = FIRST_EXTERNAL_VECTOR;
-		     vector < first_system_vector; vector++) {
+		     vector < FIRST_SYSTEM_VECTOR; vector++) {
 			if (!test_bit(vector, used_vectors) &&
 			    IS_ERR_OR_NULL(per_cpu(vector_irq, cpu)[vector])) {
 				if (++count == this_count)
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 6537cfe2cb1d2b4bf81e26b186f72b2ffc4112cd..4e5f8c022fdd3946ee998237cb2bf5bd340114c7 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -169,10 +169,7 @@ void __init native_init_IRQ(void)
 	 * 'special' SMP interrupts)
 	 */
 	i = FIRST_EXTERNAL_VECTOR;
-#ifndef CONFIG_X86_LOCAL_APIC
-#define first_system_vector NR_VECTORS
-#endif
-	for_each_clear_bit_from(i, used_vectors, first_system_vector) {
+	for_each_clear_bit_from(i, used_vectors, FIRST_SYSTEM_VECTOR) {
 		/* IA32_SYSCALL_VECTOR could be used in trap_init already. */
 		set_intr_gate(i, irq_entries_start +
 				8 * (i - FIRST_EXTERNAL_VECTOR));