diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 527519b..f2824fb 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -400,7 +400,7 @@
 
 config X86_CMPXCHG64
 	def_bool y
-	depends on X86_PAE || X86_64
+	depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM
 
 # this should be set for all -march=.. options where the compiler
 # generates cmov.
@@ -412,6 +412,7 @@
 	int
 	default "64" if X86_64
 	default "6" if X86_32 && X86_P6_NOP
+	default "5" if X86_32 && X86_CMPXCHG64
 	default "4" if X86_32 && (X86_XADD || X86_CMPXCHG || X86_BSWAP || X86_WP_WORKS_OK)
 	default "3"