x86: add noclflush option

To disable CLFLUSH usage, especially in change_page_attr().

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b8fadf5..040e30a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1191,6 +1191,8 @@
 			register save and restore. The kernel will only save
 			legacy floating-point registers on task switch.
 
+	noclflush	[BUGS=X86] Don't use the CLFLUSH instruction
+
 	nohlt		[BUGS=ARM]
 
 	no-hlt		[BUGS=X86-32] Tells the kernel that the hlt