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>

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index b3b19f4..b1c4672 100644 (file)
--- 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();
 }