x86: minor adjustment to asm constraint in get_page()

While not wrong, avoiding the unnecessary output allows the compiler a
little more freedom.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 514d66771592ba07df10fe494855e75f9256d60c..6601f78ebd1a846871874c44a0707a61d68cd1a3 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1702,8 +1702,8 @@ int get_page(struct page_info *page, struct domain *domain)
             return 0;
         }
         asm volatile (
-            LOCK_PREFIX "cmpxchg8b %3"
-            : "=d" (nd), "=a" (y), "=c" (d),
+            LOCK_PREFIX "cmpxchg8b %2"
+            : "=d" (nd), "=a" (y),
             "=m" (*(volatile u64 *)(&page->count_info))
             : "0" (d), "1" (x), "c" (d), "b" (nx) );
     }