From: Alice Ryhl <aliceryhl@google•com>
To: Mukesh Kumar Chaurasiya <mkchauras@gmail•com>
Cc: Ralf Jung <post@ralfj•de>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail•com>,
Link Mauve <linkmauve@linkmauve•fr>,
ojeda@kernel•org, boqun.feng@gmail•com, gary@garyguo•net,
bjorn3_gh@protonmail•com, lossin@kernel•org,
a.hindborg@kernel•org, tmgross@umich•edu, dakr@kernel•org,
corbet@lwn•net, maddy@linux•ibm.com, mpe@ellerman•id.au,
npiggin@gmail•com, chleroy@kernel•org, peterz@infradead•org,
jpoimboe@kernel•org, jbaron@akamai•com, rostedt@goodmis•org,
ardb@kernel•org, rust-for-linux@vger•kernel.org,
linux-doc@vger•kernel.org, linux-kernel@vger•kernel.org,
linuxppc-dev@lists•ozlabs.org,
Jubilee Young <workingjubilee@gmail•com>,
Matthew Maurer <mmaurer@google•com>,
David Wood <david@davidtw•co>, Wesley Wiser <wwiser@gmail•com>
Subject: Re: [PATCH V6 2/3] rust: Add PowerPC support
Date: Mon, 2 Mar 2026 07:29:24 +0000 [thread overview]
Message-ID: <aaU8VC-kLOKDyYDP@google.com> (raw)
In-Reply-To: <aaUlwfP72ZpshLPL@li-1a3e774c-28e4-11b2-a85c-acc9f2883e29.ibm.com>
On Mon, Mar 02, 2026 at 11:25:54AM +0530, Mukesh Kumar Chaurasiya wrote:
> On Tue, Feb 24, 2026 at 09:58:10AM +0100, Ralf Jung wrote:
> > Hi all,
> >
> > On 23.02.26 16:31, Miguel Ojeda wrote:
> > > On Mon, Feb 23, 2026 at 3:26 AM Mukesh Kumar Chaurasiya
> > > <mkchauras@gmail•com> wrote:
> > > >
> > > > I think, disabling altivec, fpu and vsx with compiler flag will work.
> > > >
> > > > What are your opinion on this?
> > >
> > > It is really up to upstream Rust -- for us, i.e. the kernel, it
> > > usually doesn't really matter much how things like that are
> > > accomplished: whether via flags, a built-in target, a custom target,
> > > etc. However, we need to know what the path to stability is.
> > >
> > > My understanding (but I may be wrong) is that upstream Rust prefer we
> > > use built-in targets for softfloat instead of disabling via
> > > `-Ctarget-feature` (and that the other options may go away soon and/or
> > > will never be stable) -- at least for some cases. For instance, for
> > > arm64, please this recent change kernel-side regarding `neon` as an
> > > entry point:
> > >
> > > 446a8351f160 ("arm64: rust: clean Rust 1.85.0 warning using softfloat target")
> > >
> > > So please ask upstream Rust (probably in their Zulip, e.g. in
> > > t-compiler or rust-for-linux channels) what you should do for powerpc.
> > > They will likely be happy with a PR adding the target (or whatever
> > > they decide) as Alice mentions. And until we reach that minimum
> > > version (in a year or more), we can use something else meanwhile. But
> > > at least we will have a way towards the end goal, if that makes sense.
> > >
> > > In case it helps, let me Cc Ralf, Jubilee and Matthew who were
> > > involved in some of that discussion in the past, plus the compiler
> > > leads.
> >
> > Upstream Rust dev here. Indeed we'd strongly prefer if this could use a
> > built-in Rust target; we can work with you on adding a new target if that is
> > needed.
> > The kernel currently uses a custom JSON target on x86 and that's quite the
> > headache for compiler development: JSON targets are highly unstable and
> > directly expose low-level details of how the compiler internally represents
> > targets. When we change that representation, we update all built-in targets,
> > but of course we cannot update JSON targets. So whenever possible we'd like
> > to move towards reducing the number of JSON targets used by the kernel, not
> > increase it. :)
> >
> > Kind regards,
> > Ralf
> >
> Hey,
>
> Sorry for delayed response. I was out of network zone.
>
> I am not sure about the process of how to get this in rust toolchain.
> Should I raise an issue of github for this?
You would need to add a new file to compiler/rustc_target/src/spec/targets
in the rustc repository.
If you're not sure what to put there, I would suggest coming up with
something that looks plausible, and opening a PR with that. Then others
can help you with filling out the target correctly.
Alice
next prev parent reply other threads:[~2026-03-02 7:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-10 9:00 [PATCH V6 0/3] Rust support for powerpc Mukesh Kumar Chaurasiya (IBM)
2026-02-10 9:00 ` [PATCH V6 1/3] powerpc/jump_label: adjust inline asm to be consistent Mukesh Kumar Chaurasiya (IBM)
2026-02-10 9:00 ` [PATCH V6 2/3] rust: Add PowerPC support Mukesh Kumar Chaurasiya (IBM)
2026-02-22 18:09 ` Alice Ryhl
2026-02-22 19:07 ` Link Mauve
2026-02-22 19:11 ` Miguel Ojeda
2026-02-23 2:21 ` Mukesh Kumar Chaurasiya
2026-02-23 2:26 ` Mukesh Kumar Chaurasiya
2026-02-23 9:22 ` Alice Ryhl
2026-02-24 4:57 ` Mukesh Kumar Chaurasiya
2026-02-23 15:31 ` Miguel Ojeda
2026-02-24 4:59 ` Mukesh Kumar Chaurasiya
2026-02-24 8:58 ` Ralf Jung
2026-03-02 5:55 ` Mukesh Kumar Chaurasiya
2026-03-02 7:29 ` Alice Ryhl [this message]
2026-03-02 12:28 ` Ralf Jung
2026-02-10 9:00 ` [PATCH V6 3/3] powerpc: Enable Rust for ppc64le Mukesh Kumar Chaurasiya (IBM)
2026-03-25 8:29 ` [PATCH V6 0/3] Rust support for powerpc Madhavan Srinivasan
2026-03-26 22:16 ` Mukesh Kumar Chaurasiya
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