Re: [PATCH v10 25/27] x86: enable initial Rust support

[Wei Liu <wei.liu@kernel.org>]

On Tue, Sep 27, 2022 at 03:14:56PM +0200, Miguel Ojeda wrote:
> Note that only x86_64 is covered and not all features nor mitigations
> are handled, but it is enough as a starting point and showcases
> the basics needed to add Rust support for a new architecture.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Co-developed-by: David Gow <davidgow@google.com>
> Signed-off-by: David Gow <davidgow@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>  Documentation/rust/arch-support.rst |  1 +
>  arch/x86/Kconfig                    |  1 +
>  arch/x86/Makefile                   | 10 ++++++++++
>  scripts/generate_rust_target.rs     | 15 +++++++++++++--
>  4 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst
> index 1152e0fbdad0..6982b63775da 100644
> --- a/Documentation/rust/arch-support.rst
> +++ b/Documentation/rust/arch-support.rst
> @@ -15,4 +15,5 @@ support corresponds to ``S`` values in the ``MAINTAINERS`` file.
>  ============  ================  ==============================================
>  Architecture  Level of support  Constraints
>  ============  ================  ==============================================
> +``x86``       Maintained        ``x86_64`` only.
>  ============  ================  ==============================================
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index f9920f1341c8..3ca198742b10 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -257,6 +257,7 @@ config X86
>  	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
>  	select HAVE_PREEMPT_DYNAMIC_CALL
>  	select HAVE_RSEQ
> +	select HAVE_RUST			if X86_64
>  	select HAVE_SYSCALL_TRACEPOINTS
>  	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
>  	select HAVE_UNSTABLE_SCHED_CLOCK
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index bafbd905e6e7..2d7e640674c6 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -68,6 +68,7 @@ export BITS
>  #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
>  #
>  KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
> +KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2

I do wonder how many more things you will need to list here. As far as
I can tell there is also other avx512* flags for the x86_64 target.

That said, if this works today ...

Reviewed-by: Wei Liu <wei.liu@kernel.org>