[src/trunk]: src/sys/external/bsd/drm2/drm Use x86_mfence explicitly, not mem...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ac70894289f9
branches:  trunk
changeset: 336567:ac70894289f9
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Mar 06 12:06:35 2015 +0000

description:
Use x86_mfence explicitly, not membar_sync, just to be clear.

diffstat:

 sys/external/bsd/drm2/drm/drm_cache.c |  9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diffs (33 lines):

diff -r 430d456d59ff -r ac70894289f9 sys/external/bsd/drm2/drm/drm_cache.c
--- a/sys/external/bsd/drm2/drm/drm_cache.c     Fri Mar 06 12:01:20 2015 +0000
+++ b/sys/external/bsd/drm2/drm/drm_cache.c     Fri Mar 06 12:06:35 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_cache.c,v 1.4 2015/03/04 18:19:27 riastradh Exp $  */
+/*     $NetBSD: drm_cache.c,v 1.5 2015/03/06 12:06:35 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: drm_cache.c,v 1.4 2015/03/04 18:19:27 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: drm_cache.c,v 1.5 2015/03/06 12:06:35 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/xcall.h>
@@ -154,11 +154,12 @@
            clflush_size);
        const char *p;
 
+       /* Support for CLFLUSH implies support for MFENCE.  */
        KASSERT(drm_md_clflush_finegrained_p());
-       membar_sync();
+       x86_mfence();
        for (p = start; p < end; p += clflush_size)
                drm_x86_clflush(p);
-       membar_sync();
+       x86_mfence();
 }
 
 #endif /* defined(__i386__) || defined(__x86_64__) */