From 2a0c772f1967565d5b71a98012e74d5a7bddc1c4 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Wed, 26 Feb 2014 12:06:51 -0700
Subject: x86: Use clflushopt in drm_clflush_page

If clflushopt is available on the system, use it instead of clflush in
drm_clflush_page.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Link: http://lkml.kernel.org/r/1393441612-19729-4-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 drivers/gpu/drm/drm_cache.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'drivers/gpu/drm')

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index bb8f58012189..c518fb6cfb63 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -32,6 +32,12 @@
 #include <drm/drmP.h>
 
 #if defined(CONFIG_X86)
+
+/*
+ * clflushopt is an unordered instruction which needs fencing with mfence or
+ * sfence to avoid ordering issues.  For drm_clflush_page this fencing happens
+ * in the caller.
+ */
 static void
 drm_clflush_page(struct page *page)
 {
@@ -44,7 +50,7 @@ drm_clflush_page(struct page *page)
 
 	page_virtual = kmap_atomic(page);
 	for (i = 0; i < PAGE_SIZE; i += size)
-		clflush(page_virtual + i);
+		clflushopt(page_virtual + i);
 	kunmap_atomic(page_virtual);
 }
 
-- 
cgit v1.2.3


From 2a0788dc9bc46789ec98aea0f30c6fb420196b12 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Wed, 26 Feb 2014 12:06:52 -0700
Subject: x86: Use clflushopt in drm_clflush_virt_range

If clflushopt is available on the system, use it instead of clflush in
drm_clflush_virt_range.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Link: http://lkml.kernel.org/r/1393441612-19729-5-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 drivers/gpu/drm/drm_cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/gpu/drm')

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index c518fb6cfb63..534cb89b160d 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -139,7 +139,7 @@ drm_clflush_virt_range(char *addr, unsigned long length)
 		mb();
 		for (; addr < end; addr += boot_cpu_data.x86_clflush_size)
 			clflush(addr);
-		clflush(end - 1);
+		clflushopt(end - 1);
 		mb();
 		return;
 	}
-- 
cgit v1.2.3