Re: Plumbers Testing MC potential topic: specialised toolchains

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

Hi Guillaume, all,

A couple of comments on the Rust bits for context.

On Tue, Jul 9, 2024 at 12:10 AM Guillaume Tucker <gtucker@gtucker.io> wrote:
>
> Then Rust support in the kernel is still work-in-progress, so the
> rustc compiler version has to closely follow the kernel revision.

I wouldn't say the reason is that the support in the kernel is
work-in-progress, but rather that `rustc` does not have all the
features the kernel needs (and "stable").

In any case, the version pinning will soon be over -- we are likely
going to have a minimum in v6.11:

    https://lore.kernel.org/rust-for-linux/20240701183625.665574-1-ojeda@kernel.org/

We are starting small, but it is already enough to cover the major
rolling distributions: Arch, Fedora, Debian Sid (outside the freeze
period) and perhaps Testing too, Gentoo, Nix unstable, openSUSE
Slowroll and Tumbleweed...

So, for some distributions, the Rust toolchain for the kernel can
already be directly from the distribution. So maybe it doesn't count
as "specialised" anymore? (at least for some distributions)

Of course, I know that you include cutting-edge too :)

> The current state of the art are the kernel.org toolchains:
>
>   https://mirrors.edge.kernel.org/pub/tools/
>
> These are for LLVM and cross-compilers, and they already solve a
> large part of the issue described above.  However, they don't
> include Rust (yet), and all the dependencies need to be installed
> manually which can have a significant impact on the build

Rust is there thanks to Nathan! :) Please see:

    https://mirrors.edge.kernel.org/pub/tools/llvm/rust/

Cheers,
Miguel