2 files changed, 10 insertions, 3 deletions

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();
 }
 
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index 32420824375b..30c9baffa96f 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -43,7 +43,7 @@
  * Because it essentially checks if buffer end is within limit and @len is
  * non-ngeative, which implies that buffer start will be within limit too.
  *
- * The reason for rewriting being, for majorit yof cases, @len is generally
+ * The reason for rewriting being, for majority of cases, @len is generally
  * compile time constant, causing first sub-expression to be compile time
  * subsumed.
  *
@@ -53,7 +53,7 @@
  *
  */
 #define __user_ok(addr, sz)     (((sz) <= TASK_SIZE) && \
-                                 (((addr)+(sz)) <= get_fs()))
+                                 ((addr) <= (get_fs() - (sz))))
 #define __access_ok(addr, sz)   (unlikely(__kernel_ok) || \
                                  likely(__user_ok((addr), (sz))))