diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 7d247b2..86a3a35 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -305,7 +305,7 @@ struct apic {
 
 	unsigned int (*get_apic_id)(unsigned long x);
 	/* Can't be NULL on 64-bit */
-	unsigned long (*set_apic_id)(unsigned int id);
+	u32 (*set_apic_id)(unsigned int id);
 
 	int (*cpu_mask_to_apicid)(const struct cpumask *cpumask,
 				  struct irq_data *irqdata,
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
index dedd5a4..6543648 100644
--- a/arch/x86/kernel/apic/apic_flat_64.c
+++ b/arch/x86/kernel/apic/apic_flat_64.c
@@ -119,7 +119,7 @@ static unsigned int flat_get_apic_id(unsigned long x)
 	return (x >> 24) & 0xFF;
 }
 
-static unsigned long set_apic_id(unsigned int id)
+static u32 set_apic_id(unsigned int id)
 {
 	return (id & 0xFF) << 24;
 }
diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
index 2fda912..d77c8cc 100644
--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -38,7 +38,7 @@ static unsigned int numachip1_get_apic_id(unsigned long x)
 	return id;
 }
 
-static unsigned long numachip1_set_apic_id(unsigned int id)
+static u32 numachip1_set_apic_id(unsigned int id)
 {
 	return (id & 0xff) << 24;
 }
@@ -51,7 +51,7 @@ static unsigned int numachip2_get_apic_id(unsigned long x)
 	return ((mcfg >> (28 - 8)) & 0xfff00) | (x >> 24);
 }
 
-static unsigned long numachip2_set_apic_id(unsigned int id)
+static u32 numachip2_set_apic_id(unsigned int id)
 {
 	return id << 24;
 }
diff --git a/arch/x86/kernel/apic/x2apic.h b/arch/x86/kernel/apic/x2apic.h
index 4c38c23..b107de3 100644
--- a/arch/x86/kernel/apic/x2apic.h
+++ b/arch/x86/kernel/apic/x2apic.h
@@ -4,6 +4,6 @@ int x2apic_apic_id_valid(int apicid);
 int x2apic_apic_id_registered(void);
 void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
 unsigned int x2apic_get_apic_id(unsigned long id);
-unsigned long x2apic_set_apic_id(unsigned int id);
+u32 x2apic_set_apic_id(unsigned int id);
 int x2apic_phys_pkg_id(int initial_apicid, int index_msb);
 void x2apic_send_IPI_self(int vector);
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index a4f2821..315c44e 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -121,7 +121,7 @@ unsigned int x2apic_get_apic_id(unsigned long id)
 	return id;
 }
 
-unsigned long x2apic_set_apic_id(unsigned int id)
+u32 x2apic_set_apic_id(unsigned int id)
 {
 	return id;
 }
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 0d57bb9..1b23b9e 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -547,7 +547,7 @@ static unsigned int x2apic_get_apic_id(unsigned long x)
 	return id;
 }
 
-static unsigned long set_apic_id(unsigned int id)
+static u32 set_apic_id(unsigned int id)
 {
 	/* CHECKME: Do we need to mask out the xapic extra bits? */
 	return id;
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
index b5e48da..652d624 100644
--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -30,7 +30,7 @@ static unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
 	return 0xfd;
 }
 
-static unsigned long xen_set_apic_id(unsigned int x)
+static u32 xen_set_apic_id(unsigned int x)
 {
 	WARN_ON(1);
 	return x;