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AFNElJ/5Z/E8NGsBbUh/65WVJ0vJyQ8YnMf4ULnnQA8INtu6Dbng5qZF5mMaWTxyLdN2qMnYcYFRy4zwBP1N2XbSGw==@vger.kernel.org X-Gm-Message-State: AOJu0YzEUtPJUuVShMaV5Ikcsu6P9VK7970++e4ZexzrVUb/3RhOuwbD IXL+eDUNP4zkNEbGnkWsmX1B6VSAyA1zHSzD62ehTiwehMgzs6tsxxyteh8x1MCkAdIzCS/hr5W NqC0oLA4+ncdlpOg0gg== X-Received: from wmbe15.prod.google.com ([2002:a05:600c:590f:b0:48f:e178:4b87]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:a402:b0:490:4033:d3df with SMTP id 5b1f17b1804b1-490426d7223mr271542435e9.23.1779878326354; Wed, 27 May 2026 03:38:46 -0700 (PDT) Date: Wed, 27 May 2026 10:38:45 +0000 In-Reply-To: Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260521165622.279953-1-japo@linux.ibm.com> <20260526161312.19291A8f-hca@linux.ibm.com> Message-ID: Subject: Re: [PATCH v3 0/4] s390: Enable Rust support and add required arch glue From: Alice Ryhl To: Miguel Ojeda Cc: Heiko Carstens , Boqun Feng , Jan Polensky , gor@linux.ibm.com, agordeev@linux.ibm.com, ojeda@kernel.org, peterz@infradead.org, jpoimboe@kernel.org, jbaron@akamai.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu, dakr@kernel.org, rostedt@goodmis.org, ardb@kernel.org, linux-s390@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Wed, May 27, 2026 at 12:08:38PM +0200, Miguel Ojeda wrote: > On Tue, May 26, 2026 at 6:13=E2=80=AFPM Heiko Carstens wrote: > > > > An Ack from you would be appreciated, even though you made it already > > clear that this series looks ok. >=20 > I did a quick `LLVM=3D1` test and booted it in QEMU. That worked and I > could see the KUnit tests, though we get the: >=20 > warning: unstable feature specified for `-Ctarget-feature`: `backchain` >=20 > But I assume you are OK with that for now (and if you are, then > avoiding a custom target is worth it, I would say). Based on some very quick research, it looks like enabling the backchain target feature does not affect the ABI in the sense that mixing together object files with and without this option will still work. If that's the case, we can add this to the list of known target features for this target in rustc, which will silence this warning. (If it affects the ABI in a breaking manner, it needs to be added as a separate flag rather than being added as part of the -Ctarget-feature flag.) Alice