diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 9da43a0fdcdffc5ff09b4e8fd1bdf6d95ac0452b..930c04c4f53cb0a5843d201534d51840d6530673 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -14,7 +14,8 @@
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
 
-unsigned int cpu_last_asid = { 1 << ASID_BITS };
+static DEFINE_SPINLOCK(cpu_asid_lock);
+unsigned int cpu_last_asid = ASID_FIRST_VERSION;
 
 /*
  * We fork()ed a process, and we need a new context for the child
@@ -31,15 +32,16 @@ void __new_context(struct mm_struct *mm)
 {
 	unsigned int asid;
 
+	spin_lock(&cpu_asid_lock);
 	asid = ++cpu_last_asid;
 	if (asid == 0)
-		asid = cpu_last_asid = 1 << ASID_BITS;
+		asid = cpu_last_asid = ASID_FIRST_VERSION;
 
 	/*
 	 * If we've used up all our ASIDs, we need
 	 * to start a new version and flush the TLB.
 	 */
-	if ((asid & ~ASID_MASK) == 0) {
+	if (unlikely((asid & ~ASID_MASK) == 0)) {
 		asid = ++cpu_last_asid;
 		/* set the reserved ASID before flushing the TLB */
 		asm("mcr	p15, 0, %0, c13, c0, 1	@ set reserved context ID\n"
@@ -48,6 +50,8 @@ void __new_context(struct mm_struct *mm)
 		isb();
 		flush_tlb_all();
 	}
+	spin_unlock(&cpu_asid_lock);
 
+	mm->cpu_vm_mask = cpumask_of_cpu(smp_processor_id());
 	mm->context.id = asid;
 }
diff --git a/include/asm-arm/mmu_context.h b/include/asm-arm/mmu_context.h
index f8755c818b5462549e39ed8bd0102ae3b02ed0a0..4981ad419198d1cf91d8f38cc0d54450f18c0c06 100644
--- a/include/asm-arm/mmu_context.h
+++ b/include/asm-arm/mmu_context.h
@@ -36,8 +36,9 @@ void __check_kvm_seq(struct mm_struct *mm);
  * The context ID is used by debuggers and trace logic, and
  * should be unique within all running processes.
  */
-#define ASID_BITS	8
-#define ASID_MASK	((~0) << ASID_BITS)
+#define ASID_BITS		8
+#define ASID_MASK		((~0) << ASID_BITS)
+#define ASID_FIRST_VERSION	(1 << ASID_BITS)
 
 extern unsigned int cpu_last_asid;
 
@@ -96,8 +97,7 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
 #ifdef CONFIG_MMU
 	unsigned int cpu = smp_processor_id();
 
-	if (prev != next) {
-		cpu_set(cpu, next->cpu_vm_mask);
+	if (!cpu_test_and_set(cpu, next->cpu_vm_mask) || prev != next) {
 		check_context(next);
 		cpu_switch_mm(next->pgd, next);
 		if (cache_is_vivt())