NACK: [SRU][M][PATCH 1/1] UBUNTU: [Packaging] define Rust flags only with Rust-enabled kernels

[Dimitri John Ledkov]

On Tue, 26 Sept 2023 at 09:32, Andrea Righi <andrea.righi at canonical.com> wrote:
>
> To enable Rust support in the kernel we need to pass special build
> flags, that are used to select the proper Rust toolchain version and
> dependent components.
>
> These flags are passed also to the scripts called during the
> updateconfigs step and the build, such as 'kernelconfig', using the
> $(kmake) variable.
>
> However, $(kmake) can also contain cross-compiler variables that may
> potentially affect the config or the build in certain architectures.

Not potentially, but intentionally.

Because sometimes we use different gcc for different arch (i.e. gcc-11
for armhf, and gcc-12 for arm64 build), and we must use full kmake for
generating the configs that should be the same as the one that will be
used for build.

I don't see how this will produce correct results. Excluding rust
variables is good, but the gcc and crosscompile should remain in place
imho.


>
> For this reason, avoid using kmake during 'updateconfigs' and explicitly
> pass the Rust flags using a separate environment variable that will be
> defined only for Rust-enabled kernels (do_lib_rust=true).
>
> Signed-off-by: Andrea Righi <andrea.righi at canonical.com>
> ---
>  debian/rules.d/0-common-vars.mk  |  2 --
>  debian/rules.d/1-maintainer.mk   |  2 +-
>  debian/rules.d/2-binary-arch.mk  | 16 ++++++++++++++++
>  debian/scripts/misc/kernelconfig |  2 +-
>  4 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/debian/rules.d/0-common-vars.mk b/debian/rules.d/0-common-vars.mk
> index 410de315afba..d62a9b063241 100644
> --- a/debian/rules.d/0-common-vars.mk
> +++ b/debian/rules.d/0-common-vars.mk
> @@ -238,8 +238,6 @@ kmake = make ARCH=$(build_arch) \
>         CROSS_COMPILE=$(CROSS_COMPILE) \
>         HOSTCC=$(HOSTCC) \
>         CC=$(CROSS_COMPILE)$(gcc) \
> -       RUSTC=rustc-1.68 HOSTRUSTC=rustc-1.68 BINDGEN=bindgen-0.56 RUSTFMT=/usr/lib/rust-1.68/bin/rustfmt RUST_LIB_SRC=/usr/src/rustc-1.68.2/library \
> -       CLANG_PATH=clang-15 LIBCLANG_PATH=/usr/lib/llvm-15/lib \
>         KERNELVERSION=$(abi_release)-$(target_flavour) \
>         CONFIG_DEBUG_SECTION_MISMATCH=y \
>         KBUILD_BUILD_VERSION="$(uploadnum)" \
> diff --git a/debian/rules.d/1-maintainer.mk b/debian/rules.d/1-maintainer.mk
> index 839e93a15371..a72e5fe93784 100644
> --- a/debian/rules.d/1-maintainer.mk
> +++ b/debian/rules.d/1-maintainer.mk
> @@ -29,7 +29,7 @@ configs-targets := updateconfigs defaultconfigs genconfigs editconfigs
>  .PHONY: $(configs-targets)
>  $(configs-targets):
>         dh_testdir
> -       kmake='$(kmake)' skip_checks=$(do_skip_checks) conc_level=$(conc_level) \
> +       RUST_FLAGS='$(RUST_FLAGS)' skip_checks=$(do_skip_checks) conc_level=$(conc_level) \
>                 $(SHELL) $(DROOT)/scripts/misc/kernelconfig $@
>
>  .PHONY: printenv
> diff --git a/debian/rules.d/2-binary-arch.mk b/debian/rules.d/2-binary-arch.mk
> index 53fbb55c198a..6e9c78aadb45 100644
> --- a/debian/rules.d/2-binary-arch.mk
> +++ b/debian/rules.d/2-binary-arch.mk
> @@ -10,6 +10,22 @@ build_cd =
>  build_O  = O=$(builddir)/build-$*
>  endif
>
> +# Define Rust build flags only for Rust-enabled kernels
> +ifeq ($(do_lib_rust),true)
> +RUST_FLAGS = \
> +       RUSTC=rustc-1.68 \
> +       HOSTRUSTC=rustc-1.68 \
> +       BINDGEN=bindgen-0.56 \
> +       RUSTFMT=/usr/lib/rust-1.68/bin/rustfmt \
> +       RUST_LIB_SRC=/usr/src/rustc-1.68.2/library \
> +       CLANG_PATH=clang-15 \
> +       LIBCLANG_PATH=/usr/lib/llvm-15/lib
> +else
> +RUST_FLAGS=
> +endif
> +
> +kmake += $(RUST_FLAGS)
> +
>  # TODO this is probably wrong, and should be using $(DEB_HOST_MULTIARCH)
>  shlibdeps_opts = $(if $(CROSS_COMPILE),-- -l$(CROSS_COMPILE:%-=/usr/%)/lib)
>
> diff --git a/debian/scripts/misc/kernelconfig b/debian/scripts/misc/kernelconfig
> index 035426762f8a..741650340b65 100755
> --- a/debian/scripts/misc/kernelconfig
> +++ b/debian/scripts/misc/kernelconfig
> @@ -118,7 +118,7 @@ EOF
>         # Call config target
>         echo
>         echo "* Run ${target} on ${arch}/${flavour} ..."
> -       ${kmake} O=build "${env[@]}" "${target}"
> +       make ${RUST_FLAGS} O=build "${env[@]}" "${target}"
>
>         # Move config for further processing
>         mv build/.config "${tmp_conf_file}"
> --
> 2.40.1
>
>
> --
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team



-- 
okurrr,

Dimitri