Kbuild provides scripts/Makefile.host to build host programs used for building the kernel. Unfortunately, there are two exceptions that opt out of Kbuild. The build system under tools/ is a cheesy replica, and cause issues. I was recently poked about a problem in the tools build system, which I do not maintain (and nobody maintains). [1] Without a comment, people might believe this is the right location because that is where objtool lives, even if a more robust Kbuild syntax satisfies their needs. [2] [1]: https://lore.kernel.org/linux-kbuild/ZnIYWBgrJ-IJtqK8@xxxxxxxxxx/T/#m8ece130dd0e23c6f2395ed89070161948dee8457 [2]: https://lore.kernel.org/all/20240618200501.GA1611012@xxxxxxxxxx/ Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Acked-by: Nicolas Schier <nicolas@xxxxxxxxx> Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx> --- Changes in v2: - rephase the comment for clarification Makefile | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Makefile b/Makefile index 768d3dc107f8..943899656977 100644 --- a/Makefile +++ b/Makefile @@ -1328,6 +1328,12 @@ prepare: tools/bpf/resolve_btfids endif endif +# The tools build system is not a part of Kbuild and tends to introduce +# its own unique issues. If you need to integrate a new tool into Kbuild, +# please consider locating that tool outside the tools/ tree and using the +# standard Kbuild "hostprogs" syntax instead of adding a new tools/* entry +# here. See Documentation/kbuild/makefiles.rst for details. + PHONY += resolve_btfids_clean resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids -- 2.43.0
