diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index 8c2b7321a478..963a2515906d 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -62,17 +62,18 @@
 #define ARM_CPU_IMP_ARM			0x41
 #define ARM_CPU_IMP_INTEL		0x69
 
-#define ARM_CPU_PART_ARM1136		0xB360
-#define ARM_CPU_PART_ARM1156		0xB560
-#define ARM_CPU_PART_ARM1176		0xB760
-#define ARM_CPU_PART_ARM11MPCORE	0xB020
-#define ARM_CPU_PART_CORTEX_A8		0xC080
-#define ARM_CPU_PART_CORTEX_A9		0xC090
-#define ARM_CPU_PART_CORTEX_A5		0xC050
-#define ARM_CPU_PART_CORTEX_A15		0xC0F0
-#define ARM_CPU_PART_CORTEX_A7		0xC070
-#define ARM_CPU_PART_CORTEX_A12		0xC0D0
-#define ARM_CPU_PART_CORTEX_A17		0xC0E0
+/* ARM implemented processors */
+#define ARM_CPU_PART_ARM1136		0x4100b360
+#define ARM_CPU_PART_ARM1156		0x4100b560
+#define ARM_CPU_PART_ARM1176		0x4100b760
+#define ARM_CPU_PART_ARM11MPCORE	0x4100b020
+#define ARM_CPU_PART_CORTEX_A8		0x4100c080
+#define ARM_CPU_PART_CORTEX_A9		0x4100c090
+#define ARM_CPU_PART_CORTEX_A5		0x4100c050
+#define ARM_CPU_PART_CORTEX_A7		0x4100c070
+#define ARM_CPU_PART_CORTEX_A12		0x4100c0d0
+#define ARM_CPU_PART_CORTEX_A17		0x4100c0e0
+#define ARM_CPU_PART_CORTEX_A15		0x4100c0f0
 
 #define ARM_CPU_XSCALE_ARCH_MASK	0xe000
 #define ARM_CPU_XSCALE_ARCH_V1		0x2000
@@ -171,14 +172,24 @@ static inline unsigned int __attribute_const__ read_cpuid_implementor(void)
 	return (read_cpuid_id() & 0xFF000000) >> 24;
 }
 
-static inline unsigned int __attribute_const__ read_cpuid_part_number(void)
+/*
+ * The CPU part number is meaningless without referring to the CPU
+ * implementer: implementers are free to define their own part numbers
+ * which are permitted to clash with other implementer part numbers.
+ */
+static inline unsigned int __attribute_const__ read_cpuid_part(void)
+{
+	return read_cpuid_id() & 0xff00fff0;
+}
+
+static inline unsigned int __attribute_const__ __deprecated read_cpuid_part_number(void)
 {
 	return read_cpuid_id() & 0xFFF0;
 }
 
 static inline unsigned int __attribute_const__ xscale_cpu_arch_version(void)
 {
-	return read_cpuid_part_number() & ARM_CPU_XSCALE_ARCH_MASK;
+	return read_cpuid_id() & ARM_CPU_XSCALE_ARCH_MASK;
 }
 
 static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
index 0393fbab8dd5..bfe163c40024 100644
--- a/arch/arm/include/asm/smp_scu.h
+++ b/arch/arm/include/asm/smp_scu.h
@@ -11,7 +11,7 @@
 
 static inline bool scu_a9_has_base(void)
 {
-	return read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9;
+	return read_cpuid_part() == ARM_CPU_PART_CORTEX_A9;
 }
 
 static inline unsigned long scu_a9_get_base(void)
diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c
index af9e35e8836f..c02c2e8c877d 100644
--- a/arch/arm/kernel/perf_event_cpu.c
+++ b/arch/arm/kernel/perf_event_cpu.c
@@ -250,40 +250,38 @@ static struct platform_device_id cpu_pmu_plat_device_ids[] = {
 static int probe_current_pmu(struct arm_pmu *pmu)
 {
 	int cpu = get_cpu();
-	unsigned long implementor = read_cpuid_implementor();
-	unsigned long part_number = read_cpuid_part_number();
 	int ret = -ENODEV;
 
 	pr_info("probing PMU on CPU %d\n", cpu);
 
+	switch (read_cpuid_part()) {
 	/* ARM Ltd CPUs. */
-	if (implementor == ARM_CPU_IMP_ARM) {
-		switch (part_number) {
-		case ARM_CPU_PART_ARM1136:
-		case ARM_CPU_PART_ARM1156:
-		case ARM_CPU_PART_ARM1176:
-			ret = armv6pmu_init(pmu);
-			break;
-		case ARM_CPU_PART_ARM11MPCORE:
-			ret = armv6mpcore_pmu_init(pmu);
-			break;
-		case ARM_CPU_PART_CORTEX_A8:
-			ret = armv7_a8_pmu_init(pmu);
-			break;
-		case ARM_CPU_PART_CORTEX_A9:
-			ret = armv7_a9_pmu_init(pmu);
-			break;
-		}
-	/* Intel CPUs [xscale]. */
-	} else if (implementor == ARM_CPU_IMP_INTEL) {
-		switch (xscale_cpu_arch_version()) {
-		case ARM_CPU_XSCALE_ARCH_V1:
-			ret = xscale1pmu_init(pmu);
-			break;
-		case ARM_CPU_XSCALE_ARCH_V2:
-			ret = xscale2pmu_init(pmu);
-			break;
+	case ARM_CPU_PART_ARM1136:
+	case ARM_CPU_PART_ARM1156:
+	case ARM_CPU_PART_ARM1176:
+		ret = armv6pmu_init(pmu);
+		break;
+	case ARM_CPU_PART_ARM11MPCORE:
+		ret = armv6mpcore_pmu_init(pmu);
+		break;
+	case ARM_CPU_PART_CORTEX_A8:
+		ret = armv7_a8_pmu_init(pmu);
+		break;
+	case ARM_CPU_PART_CORTEX_A9:
+		ret = armv7_a9_pmu_init(pmu);
+		break;
+	default:
+		if (read_cpuid_implementor() == ARM_CPU_IMP_INTEL) {
+			switch (xscale_cpu_arch_version()) {
+			case ARM_CPU_XSCALE_ARCH_V1:
+				ret = xscale1pmu_init(pmu);
+				break;
+			case ARM_CPU_XSCALE_ARCH_V2:
+				ret = xscale2pmu_init(pmu);
+				break;
+			}
 		}
+		break;
 	}
 
 	put_cpu();
diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
index b23a59c1c522..70bf49b8b244 100644
--- a/arch/arm/kvm/guest.c
+++ b/arch/arm/kvm/guest.c
@@ -274,13 +274,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 
 int __attribute_const__ kvm_target_cpu(void)
 {
-	unsigned long implementor = read_cpuid_implementor();
-	unsigned long part_number = read_cpuid_part_number();
-
-	if (implementor != ARM_CPU_IMP_ARM)
-		return -EINVAL;
-
-	switch (part_number) {
+	switch (read_cpuid_part()) {
 	case ARM_CPU_PART_CORTEX_A7:
 		return KVM_ARM_TARGET_CORTEX_A7;
 	case ARM_CPU_PART_CORTEX_A15:
diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index 0498d0b887ef..5cb0c9d60825 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -197,7 +197,7 @@ static void exynos_power_down(void)
 	if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
 		arch_spin_unlock(&exynos_mcpm_lock);
 
-		if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
+		if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
 			/*
 			 * On the Cortex-A15 we need to disable
 			 * L2 prefetching before flushing the cache.
diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 1c8d31e39520..8dc1d3a3a8bf 100644
--- a/arch/arm/mach-exynos/platsmp.c
+++ b/arch/arm/mach-exynos/platsmp.c
@@ -188,7 +188,7 @@ static void __init exynos_smp_init_cpus(void)
 	void __iomem *scu_base = scu_base_addr();
 	unsigned int i, ncores;
 
-	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
+	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9)
 		ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 	else
 		/*
@@ -214,7 +214,7 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 
 	exynos_sysram_init();
 
-	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
+	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9)
 		scu_enable(scu_base_addr());
 
 	/*
diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index b743a0ae02ce..154669ccaca6 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -152,7 +152,7 @@ static void tc2_pm_down(u64 residency)
 	if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
 		arch_spin_unlock(&tc2_pm_lock);
 
-		if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
+		if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
 			/*
 			 * On the Cortex-A15 we need to disable
 			 * L2 prefetching before flushing the cache.
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index c012a673b4ef..948f12cf6180 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -733,7 +733,7 @@ static int l2c310_cpu_enable_flz(struct notifier_block *nb, unsigned long act, v
 static void __init l2c310_enable(void __iomem *base, u32 aux, unsigned num_lock)
 {
 	unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_PART_MASK;
-	bool cortex_a9 = read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9;
+	bool cortex_a9 = read_cpuid_part() == ARM_CPU_PART_CORTEX_A9;
 
 	if (rev >= L310_CACHE_ID_RTL_R2P0) {
 		if (cortex_a9) {
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index 60e5a170c4d2..e6833771a716 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -250,7 +250,7 @@ static void __init global_timer_of_register(struct device_node *np)
 	 * fire when the timer value is greater than or equal to. In previous
 	 * revisions the comparators fired when the timer value was equal to.
 	 */
-	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9
+	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9
 	    && (read_cpuid_id() & 0xf0000f) < 0x200000) {
 		pr_warn("global-timer: non support for this cpu version.\n");
 		return;
