On Mon, Feb 10, 2025 at 05:42:45PM +0100, Miguel Ojeda wrote:
> Introduce `rustc-min-version` support function that mimics
> `{gcc,clang}-min-version` ones, following commit 88b61e3bff93
> ("Makefile.compiler: replace cc-ifversion with compiler-specific macros").
>
> In addition, use it in the first use case we have in the kernel (which
> was done independently to minimize the changes needed for the fix).
>
> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
> ---
> This is based on top of the fix so that the fix remains as simple as
> possible:
>
> https://lore.kernel.org/rust-for-linux/20250210163732.281786-1-ojeda@xxxxxxxxxx/
>
> Documentation/kbuild/makefiles.rst | 14 ++++++++++++++
> arch/arm64/Makefile | 2 +-
> scripts/Makefile.compiler | 4 ++++
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
> index d36519f194dc..2608aa32c762 100644
> --- a/Documentation/kbuild/makefiles.rst
> +++ b/Documentation/kbuild/makefiles.rst
> @@ -670,6 +670,20 @@ cc-cross-prefix
> endif
> endif
>
> +$(RUSTC) support functions
> +--------------------------
> +
> +rustc-min-version
> + rustc-min-version tests if the value of $(CONFIG_RUSTC_VERSION) is greater
> + than or equal to the provided value and evaluates to y if so.
> +
> + Example::
> +
> + rustflags-$(call rustc-min-version, 108500) := -Cfoo
> +
> + In this example, rustflags-y will be assigned the value -Cfoo if
> + $(CONFIG_RUSTC_VERSION) is >= 1.85.0.
> +
> $(LD) support functions
> -----------------------
>
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 2b25d671365f..1d5dfcd1c13e 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -48,7 +48,7 @@ KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU) \
> KBUILD_CFLAGS += $(call cc-disable-warning, psabi)
> KBUILD_AFLAGS += $(compat_vdso)
>
> -ifeq ($(call test-ge, $(CONFIG_RUSTC_VERSION), 108500),y)
> +ifeq ($(call rustc-min-version, 108500),y)
> KBUILD_RUSTFLAGS += --target=aarch64-unknown-none-softfloat
> else
> KBUILD_RUSTFLAGS += --target=aarch64-unknown-none -Ctarget-feature="-neon"
> diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
> index 8c1029687e2e..8956587b8547 100644
> --- a/scripts/Makefile.compiler
> +++ b/scripts/Makefile.compiler
> @@ -67,6 +67,10 @@ gcc-min-version = $(call test-ge, $(CONFIG_GCC_VERSION), $1)
> # Usage: cflags-$(call clang-min-version, 110000) += -foo
> clang-min-version = $(call test-ge, $(CONFIG_CLANG_VERSION), $1)
>
> +# rustc-min-version
> +# Usage: rustc-$(call rustc-min-version, 108500) += -Cfoo
> +rustc-min-version = $(call test-ge, $(CONFIG_RUSTC_VERSION), $1)
> +
> # ld-option
> # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
> ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
> --
> 2.48.1
Reviewed-by: Nicolas Schier <n.schier@xxxxxx>
