On Tue, Mar 04, 2025 at 08:21:29AM -0800, Kees Cook wrote:
> The UM builds distinguish i386 from x86_64 via SUBARCH, but we don't
> support building i386 directly with Clang. To make SUBARCH work for
> i386 UM, we need to explicitly test for it.
>
> This lets me run i386 KUnit tests with Clang:
>
> $ ./tools/testing/kunit/kunit.py run \
> --make_options LLVM=1 \
> --make_options SUBARCH=i386
> ...
>
> Fixes: c7500c1b53bf ("um: Allow builds with Clang")
> Signed-off-by: Kees Cook <k...@kernel.org>
Reviewed-by: Nathan Chancellor <nat...@kernel.org>
> ---
> Cc: Nathan Chancellor <nat...@kernel.org>
> Cc: Thomas Weißschuh <li...@weissschuh.net>
> Cc: Bill Wendling <mo...@google.com>
> Cc: Justin Stitt <justinst...@google.com>
> Cc: Masahiro Yamada <masahi...@kernel.org>
> Cc: Nicolas Schier <nico...@fjasle.eu>
> Cc: l...@lists.linux.dev
> Cc: linux-kbu...@vger.kernel.org
> ---
> scripts/Makefile.clang | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang
> index 2435efae67f5..b67636b28c35 100644
> --- a/scripts/Makefile.clang
> +++ b/scripts/Makefile.clang
> @@ -12,6 +12,8 @@ CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu
> CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu
> CLANG_TARGET_FLAGS_sparc := sparc64-linux-gnu
> CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu
> +# This is only for i386 UM builds, which need the 32-bit target not -m32
> +CLANG_TARGET_FLAGS_i386 := i386-linux-gnu
> CLANG_TARGET_FLAGS_um := $(CLANG_TARGET_FLAGS_$(SUBARCH))
> CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH))
>
> --
> 2.34.1
>
