Re: [PATCH v3 02/16] kbuild: userprogs: also inherit byte order and ABI from kernel

[Masahiro Yamada <masahiroy@kernel.org>]

On Wed, Jun 11, 2025 at 4:38 PM Thomas Weißschuh
<thomas.weissschuh@linutronix.de> wrote:
>
> Make sure the byte order and ABI of the userprogs matches the one of the
> kernel, similar to how the bit size is handled.
> Otherwise the userprogs may not be executable.
> This happens for example on powerpc little endian, or riscv32.
>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>  Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index c4293cf91e968ca8ee64452841fb266e24df63f6..b9aa1058321dabd3b3dd5610e45a2807dfa257f4 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1129,8 +1129,8 @@ ifneq ($(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS),)
>  LDFLAGS_vmlinux        += --emit-relocs --discard-none
>  endif
>
> -# Align the bit size of userspace programs with the kernel
> -USERFLAGS_FROM_KERNEL := -m32 -m64 --target=%
> +# Align the bit size, byte order and architecture of userspace programs with the kernel
> +USERFLAGS_FROM_KERNEL := -m32 -m64 -mlittle-endian -mbig-endian --target=% -march=% -mabi=%
>  KBUILD_USERCFLAGS  += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
>  KBUILD_USERLDFLAGS += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))


Why didn't you do like this?

USERFLAGS_FROM_KERNEL := $(filter -m32 -m64 -mlittle-endian
-mbig-endian --target=% -march=% -mabi=%, $(KBUILD_CPPFLAGS)
$(KBUILD_CFLAGS))
KBUILD_USERCFLAGS  += $(USERFLAGS_FROM_KERNEL)
KBUILD_USERLDFLAGS += $(USERFLAGS_FROM_KERNEL)



--
Best Regards
Masahiro Yamada