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| author | Masahiro Yamada <masahiroy@kernel.org> | 2020-05-25 00:42:15 +0900 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2020-05-29 03:08:49 +0900 |
| commit | e9e81b634303b215e83beced03f04f02f7893442 (patch) | |
| tree | c1ba8052b8020f6e3affb3e8b6e085933db7e4f1 /Makefile | |
| parent | 454753d9f67ae40b6a2142ddb6b4dbdcc9654aa9 (diff) | |
| download | lwn-e9e81b634303b215e83beced03f04f02f7893442.tar.gz lwn-e9e81b634303b215e83beced03f04f02f7893442.zip | |
kbuild: disallow multi-word in M= or KBUILD_EXTMOD
$(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.
It was a solution to resolve symbol dependencies when an external
module depends on another external module.
Commit 0d96fb20b7ed ("kbuild: Add new Kbuild variable
KBUILD_EXTRA_SYMBOLS") introduced another solution by passing symbol
info via KBUILD_EXTRA_SYMBOLS, then broke the multi-word M= support.
include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
... does not work if KBUILD_EXTMOD contains multiple words.
This feature has been broken for more than a decade. Remove the
bitrotten code, and stop parsing if M or KBUILD_EXTMOD contains
multiple words.
As Documentation/kbuild/modules.rst explains, if your module depends
on another one, there are two solutions:
- add a common top-level Kbuild file
- use KBUILD_EXTRA_SYMBOLS
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -218,6 +218,9 @@ ifeq ("$(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)/) |