[PATCH 6/6] x86: Use clwb in drm_clflush_virt_range

[Ross Zwisler <ross.zwisler@linux.intel.com>]

If clwb is available on the system, use it in drm_clflush_virt_range.
If clwb is not available, fall back to clflushopt if you can.
If clflushopt is not supported, fall all the way back to clflush.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: H Peter Anvin <h.peter.anvin@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: x86@kernel.org
---
 drivers/gpu/drm/drm_cache.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index aad9d82..84e9a04 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -138,8 +138,8 @@ drm_clflush_virt_range(void *addr, unsigned long length)
 		void *end = addr + length;
 		mb();
 		for (; addr < end; addr += boot_cpu_data.x86_clflush_size)
-			clflushopt(addr);
-		clflushopt(end - 1);
+			clwb(addr);
+		clwb(end - 1);
 		mb();
 		return;
 	}
-- 
1.9.3