[PATCH 09/29] kbuild: disallow multi-word in M= or KBUILD_EXTMOD

Masahiro Yamada
2020-05-17T09:49:47Z

$(firstword ...) in scripts/Makefile.modpost was added by commit
3f3fd3c05585 ("[PATCH] kbuild: allow multi-word $M in Makefile.modpost")
to build multiple external module directories.

This feature has been broken for a while. Remove the bitrotten code, and
stop parsing if M or KBUILD_EXTMOD contains multiple words.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Makefile | 3 +++
scripts/Makefile.modpost | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 1915630cc24b..aeb690c692ee 100644
--- a/Makefile
+++ b/Makefile
@@ -218,6 +218,9 @@ ifeq ("$(origin M)", "command line")
KBUILD_EXTMOD := $(M)
endif

+$(if $(word 2, $(KBUILD_EXTMOD)), \
+ $(error building multiple external modules is not supported))
+
export KBUILD_CHECKSRC KBUILD_EXTMOD

extmod-prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 957eed6a17a5..b79bf0e30d32 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -44,7 +44,7 @@ include include/config/auto.conf
include scripts/Kbuild.include

kernelsymfile := $(objtree)/Module.symvers
-modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
+modulesymfile := $(KBUILD_EXTMOD)/Module.symvers

MODPOST = scripts/mod/modpost \
$(if $(CONFIG_MODVERSIONS),-m) \
--
2.25.1