diff --git a/arch/arc/include/asm/spinlock.h b/arch/arc/include/asm/spinlock.h
index f158197ac5b0..b6a8c2dfbe6e 100644
--- a/arch/arc/include/asm/spinlock.h
+++ b/arch/arc/include/asm/spinlock.h
@@ -45,7 +45,14 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
 
 static inline void arch_spin_unlock(arch_spinlock_t *lock)
 {
-	lock->slock = __ARCH_SPIN_LOCK_UNLOCKED__;
+	unsigned int tmp = __ARCH_SPIN_LOCK_UNLOCKED__;
+
+	__asm__ __volatile__(
+	"	ex  %0, [%1]		\n"
+	: "+r" (tmp)
+	: "r"(&(lock->slock))
+	: "memory");
+
 	smp_mb();
 }