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authorMasahiro Yamada <masahiroy@kernel.org>2022-12-13 14:24:20 +0300
committerMasahiro Yamada <masahiroy@kernel.org>2022-12-14 09:42:40 +0300
commit87d599fc3955e59b1ed30f350321a4be5353f945 (patch)
treef43f5dc1ec8a0e381d011c63f4f4989964c025eb /Makefile
parent3d57e1b7b1d42d4040f0d993b66ff06beda02c54 (diff)
downloadlinux-87d599fc3955e59b1ed30f350321a4be5353f945.tar.xz
kbuild: ensure Make >= 3.82 is used
Documentation/process/changes.rst notes the minimal GNU Make version, but it is not checked anywhere. We could check $(MAKE_VERSION), but another simple way is to check $(.FEATURES) since the feature list always grows. GNU Make 3.81 expands $(.FEATURES) to: target-specific order-only second-expansion else-if archives jobserver check-symlink GNU Make 3.82 expands $(.FEATURES) to: target-specific order-only second-expansion else-if shortest-stem undefine archives jobserver check-symlink To ensure Make >= 3.82, you can check either 'shortest-stem' or 'undefine'. This way is not always possible. For example, Make 4.0 through 4.2 have the same set of $(.FEATURES). At that point, we will need to come up with a different approach. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile4
1 files changed, 4 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index f506879e7452..5f015f206e12 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,10 @@ NAME = Hurr durr I'ma ninja sloth
# Comments in this file are targeted only to the developer, do not
# expect to learn how to build the kernel reading this file.
+ifeq ($(filter undefine,$(.FEATURES)),)
+$(error GNU Make >= 3.82 is required. Your Make version is $(MAKE_VERSION))
+endif
+
$(if $(filter __%, $(MAKECMDGOALS)), \
$(error targets prefixed with '__' are only for internal use))