random: Fix behavior of kernel option "-rs".

[pintos-anon] / src / threads / synch.h

diff --git a/src/threads/synch.h b/src/threads/synch.h
index 6b8f550e8798f6b9b916cf15ce8ec72861e283a8..a19e88b181dff1208839ff890154aa69b299ce91 100644 (file)
--- a/src/threads/synch.h
+++ b/src/threads/synch.h
@@ -44,7 +44,8 @@ void cond_broadcast (struct condition *, struct lock *);
 /* Optimization barrier.
 
    The compiler will not reorder operations across an
-   optimization barrier. */
-#define barrier() asm volatile ("")
+   optimization barrier.  See "Optimization Barriers" in the
+   reference guide for more information.*/
+#define barrier() asm volatile ("" : : : "memory")
 
 #endif /* threads/synch.h */