[PATCH 3/4] kbuild: error out if $(KBUILD_EXTMOD) contains % or :

[Masahiro Yamada]

If the directory pass given to KBUILD_EXTMOD (or M=) contains % or :,
the module fails to build.

% is used in pattern rules, and : as the separator of dependencies.

Bail out with a clearer error message.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

 Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Makefile b/Makefile
index faa4880f25f7..ecda62e27553 100644
--- a/Makefile
+++ b/Makefile
@@ -129,6 +129,9 @@ endif
 $(if $(word 2, $(KBUILD_EXTMOD)), \
 	$(error building multiple external modules is not supported))
 
+$(foreach x, % :, $(if $(findstring $x, $(KBUILD_EXTMOD)), \
+	$(error module directory path cannot contain '$x')))
+
 # Remove trailing slashes
 ifneq ($(filter %/, $(KBUILD_EXTMOD)),)
 KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).)
-- 
2.34.1