[tip:x86/cpu] x86: Use clflushopt in clflush_cache_range

[tip-bot for Ross Zwisler <tipbot@zytor.com>]

Commit-ID:  8b80fd8b45458a7d0b726d454c51c5219e0fb2ee
Gitweb:     http://git.kernel.org/tip/8b80fd8b45458a7d0b726d454c51c5219e0fb2ee
Author:     Ross Zwisler <ross.zwisler@linux.intel.com>
AuthorDate: Wed, 26 Feb 2014 12:06:50 -0700
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Thu, 27 Feb 2014 08:26:10 -0800

x86: Use clflushopt in clflush_cache_range

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

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Link: http://lkml.kernel.org/r/1393441612-19729-3-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/mm/pageattr.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index b3b19f4..b1c4672 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -126,8 +126,8 @@ within(unsigned long addr, unsigned long start, unsigned long end)
  * @vaddr:	virtual start address
  * @size:	number of bytes to flush
  *
- * clflush is an unordered instruction which needs fencing with mfence
- * to avoid ordering issues.
+ * clflushopt is an unordered instruction which needs fencing with mfence or
+ * sfence to avoid ordering issues.
  */
 void clflush_cache_range(void *vaddr, unsigned int size)
 {
@@ -136,11 +136,11 @@ void clflush_cache_range(void *vaddr, unsigned int size)
 	mb();
 
 	for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
-		clflush(vaddr);
+		clflushopt(vaddr);
 	/*
 	 * Flush any possible final partial cacheline:
 	 */
-	clflush(vend);
+	clflushopt(vend);
 
 	mb();
 }