[PATCH] RISC-V: Fix building rust when using GCC toolchain

[Gary Guo]

On Mon, 16 Sep 2024 20:08:48 -0400
Jason Montleon <jmontleo at redhat.com> wrote:

> Clang does not support '-mno-riscv-attribute' resulting in the error
> error: unknown argument: '-mno-riscv-attribute'
> 
> Not setting BINDGEN_TARGET_riscv results in the in the error
> error: unsupported argument 'medany' to option '-mcmodel=' for target \
> 'unknown'
> error: unknown target triple 'unknown'
> 
> Signed-off-by: Jason Montleon <jmontleo at redhat.com>
> Cc: stable at vger.kernel.org

I also carry a similar patch locally (haven't get around to submit it
yet), so I can confirm

Tested-by: Gary Guo <garyguo.net>

As Conor points out, the commit message could be improved. Perhaps add
a bit of context about the flag filtering.

Best,
Gary

> ---
>  rust/Makefile | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/rust/Makefile b/rust/Makefile
> index f168d2c98a15..73eceaaae61e 100644
> --- a/rust/Makefile
> +++ b/rust/Makefile
> @@ -228,11 +228,12 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
>  	-fzero-call-used-regs=% -fno-stack-clash-protection \
>  	-fno-inline-functions-called-once -fsanitize=bounds-strict \
>  	-fstrict-flex-arrays=% -fmin-function-alignment=% \
> -	--param=% --param asan-%
> +	--param=% --param asan-% -mno-riscv-attribute
>  
>  # Derived from `scripts/Makefile.clang`.
>  BINDGEN_TARGET_x86	:= x86_64-linux-gnu
>  BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
> +BINDGEN_TARGET_riscv	:= riscv64-linux-gnu
>  BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
>  
>  # All warnings are inhibited since GCC builds are very experimental,
> 
> base-commit: ad060dbbcfcfcba624ef1a75e1d71365a98b86d8