Re: [PATCH v4 01/15] kbuild: userprogs: avoid duplication of flags inherited from kernel

[Masahiro Yamada <masahiroy@kernel.org>]

On Thu, Jun 26, 2025 at 3:10 PM Thomas Weißschuh
<thomas.weissschuh@linutronix.de> wrote:
>
> The duplication makes maintenance harder. Changes need to be done in two
> places and the lines will grow overly long.
>
> Use an intermediary variable instead.
>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>  Makefile | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 35e6e5240c61a8a329011929fcd0352b881dccdc..c4293cf91e968ca8ee64452841fb266e24df63f6 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1130,8 +1130,9 @@ LDFLAGS_vmlinux   += --emit-relocs --discard-none
>  endif
>
>  # Align the bit size of userspace programs with the kernel
> -KBUILD_USERCFLAGS  += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
> -KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
> +USERFLAGS_FROM_KERNEL := -m32 -m64 --target=%
> +KBUILD_USERCFLAGS  += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
> +KBUILD_USERLDFLAGS += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
>

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

However, as I mentioned before, the following code is shorter.

USERFLAGS_FROM_KERNEL := $(filter -m32 -m64 --target=%,
$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
KBUILD_USERCFLAGS  += $(USERFLAGS_FROM_KERNEL)
KBUILD_USERLDFLAGS += $(USERFLAGS_FROM_KERNEL)



-- 
Best Regards
Masahiro Yamada