diff --git a/Makefile b/Makefile
index 34d6176..c3a7271 100644
--- a/Makefile
+++ b/Makefile
@@ -263,6 +263,13 @@
 # cc support functions to be used (only) in arch/$(ARCH)/Makefile
 # See documentation in Documentation/kbuild/makefiles.txt
 
+# as-option
+# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
+
+as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
+	     -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
+	     else echo "$(2)"; fi ;)
+
 # cc-option
 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)