Merge pull request #2204 from hjelmn/arm64

asm/arm64: ensure instruction ordering on timer

opal/include/opal/sys/arm64/timer.h

@@ -1,8 +1,11 @@
+/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
 /*
  * Copyright (c) 2008      The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2016      Broadcom Limited. All rights reserved.
+ * Copyright (c) 2016      Los Alamos National Security, LLC. All rights
+ *                         reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -22,6 +25,7 @@ opal_sys_timer_get_cycles(void)
 {
     opal_timer_t ret;
 
+    __asm__ __volatile__ ("isb" ::: "memory");
     __asm__ __volatile__ ("mrs %0,  CNTVCT_EL0" : "=r" (ret));
 
     return ret;