Re: [PATCH v3 0/1] RISC-V: enable rust

["Björn Töpel" <bjorn@kernel.org>]

Conor Dooley <conor@kernel.org> writes:

> From: Conor Dooley <conor.dooley@microchip.com>
>
> I've intentionally not turned on the gcc support, as discussed on
> v1. I've also switched over to using the target, but it is a bit heavier
> than the one arm64 seems to be using. RISC-V has fewer targets available
> and this was the closest. I preserved the redzone disabling, just moved
> into the Makefile. Any comment from Gary or the LLVM lads on the target
> would be great I think:
> https://github.com/rust-lang/rust/blob/master/compiler/rustc_target/src/spec/targets/riscv64imac_unknown_none_elf.rs
> arm64 is using:
> https://github.com/rust-lang/rust/blob/master/compiler/rustc_target/src/spec/targets/aarch64_unknown_none.rs
>
> I was gonna send this yesterday, but found out last minute I had invalid
> code in the target generation script. The kernel test robot had given my
> branch the global all-clear - the rust coverage with all the
> "depends on !FOO" must really limit the build coverage. I built for x86
> with rust enabled locally this time to make sure..
>
> As this as lifted from the state of the Rust-for-Linux tree, the commit
> messages from there cannot be preserved, so these patches have commit
> messages that I wrote.
>
> I've tested this on Icicle, and the modules seem to work as expected.
> Unfortunately there appear to be implicit 32-bit divisions (or similar)
> in core Rust code, so, as in the downstream Rust-for-Linux tree, Rust is
> only enabled for 64-bit.

Nice, works with my simple test on VisionFive 2 as well! Cool to have
Rust support in! Now, BTF just needs to be supported, and I can have
Rust *and* BPF in my kernels! :-P \o/

Tested-by: Björn Töpel <bjorn@rivosinc.com>