Re: [PATCH v2 0/6] Rust: support `CPU_MITIGATIONS` and enable `objtool`

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Jul 24, 2024 at 06:14:53PM +0200, Miguel Ojeda wrote:
> Hi,
> 
> This is an updated series to the CPU mitigations support for Rust. It
> also has the patch to enable `objtool`, so that we can start running it
> for Rust.
> 
> It would be nice to get this applied soon, so that we start being
> warning-free (since we already get warnings under IBT builds via
> `vmlinux.o`). I am happy to take it through the Rust tree if the x86 and
> objtool maintainers give an Acked-by, or through any of the other trees,
> as you prefer. Otherwise, I think at this point we would need to make
> Rust exclusive to the mitigations, which isn't great.
> 
> With this series, again, x86_64 is warning-free with `objtool` enabled. I
> tested `-O2`/`-Os` and the Rust versions we support under `-O2` (mainly
> for the `noreturn` patch, which uses heuristics), as well as IBT vs. no
> IBT (i.e.  running on individual object files vs. in `vmlinux`). I also
> did an arm64 build.

W00t :-)

Aside from a small niggle about maybe doing a helper function for those
Rust runtime things, I don't see anything objectionable here.

Thanks!