Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO

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

On Thu, Mar 26, 2026 at 3:42 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> I do agree with some of the concerns that adding an architecure
> dimension to this is a little complicated. I would rather try to flush
> out those build problems with patches and keep it enabled for all
> architectures. At the same time though, I understand that enabling it
> for the "tier 1" architectures is a low barrier of entry for getting the
> feature upstream, validated, and distributed to the majority of people
> that would actually use and depend on it, so I ultimately leave that
> call up to you.

Thanks! I agree that it would be ideal to get it clean everywhere, but
given it is experimental and that arch maintainers should likely known
about this, I think it is best to start simple first.

In fact, let me Cc the x86 and arm64 maintainers so that they are aware.

My current thinking is that I will add:

  depends on ARM64 || X86_64

and try to land it this cycle.

My understanding is that this will be used at least by Google, mostly
for Android (and mostly arm64, but possibly x86_64 too), so I think at
least arm64 will see some actual users on an ongoing basis, i.e. apart
from the "synthetic" testing I was doing.

> No real concern on that front but .gitignore has a command to run when
> modifying it, which will require a !timeconst.bc in a
> kernel/time/.gitignore file.

Yeah, that is the exception I mentioned. Initially I thought about
putting it in a local `.gitignore`, because local is best. But another
option, with a different kind of locality, is keeping the exception
close to the rule, i.e. in the global one, which has the advantage of
showing us all the exceptions easily (and being able to write a
comment for all of them at once).

I am not sure what is best clearer, but I am happy to do either:

    diff --git a/.gitignore b/.gitignore
    index 3a7241c941f5..3044b9590f05 100644
    --- a/.gitignore
    +++ b/.gitignore
    @@ -13,6 +13,7 @@
     .*
     *.a
     *.asn1.[ch]
    +*.bc
     *.bin
     *.bz2
     *.c.[012]*.*
    @@ -184,3 +185,6 @@ sphinx_*/

     # Rust analyzer configuration
     /rust-project.json
    +
    +# bc language scripts (not LLVM bitcode)
    +!kernel/time/timeconst.bc

Thanks again!

Cheers,
Miguel