Re: [PATCH v3 0/4] s390: Enable Rust support and add required arch glue

[Miguel Ojeda]

On Wed, May 27, 2026 at 3:44 PM Heiko Carstens <hca@xxxxxxxxxxxxx> wrote:
>
> I guess you meant `-Zpacked-stack`? We need both `-Zpacked-stack`, as
> well as `-Ctarget-feature=+backchain`. Otherwise the result would be
> incorrect code, due to different stack layouts.

Yeah, I was referring to the case when the softfloat target is not
used, i.e. I was replying to Alice in general terms for upstream Rust.
The combination in the patch here is accepted.

By the way, the compiler diagnostic added by Eddy (a colleague of
yours, I assume) that mentions it is nice:

  error: `-Zpacked-stack` is incompatible with `backchain` target feature
    |
    = note: enabling both `-Zpacked-stack` and the `backchain` target
feature is incompatible with the default s390x ABI. Switch to
s390x-unknown-none-softfloat if you need both attributes

Cheers,
Miguel