From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F35E240BCD8; Mon, 15 Jun 2026 16:40:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781541621; cv=none; b=MeQ6bKoyLGat43FTYZPsXLhjIfhzu3DmPsvmq4eYgEymmIgNyNHpU2Mz6BRYVjo+RsQ0I6eEGq1ttR5J9rFUEAWIkliogPQGjGdHNkW9B8QkWDAl4aKgqmmIwfrVGjgkT/DiyEivMyh92SvWkRwBaBI7F82lYTJBduRAM1T0rZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781541621; c=relaxed/simple; bh=fMataVjVawB4LuTgNwBuwtbEgT0ewSM13MLu+YUD/ZU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eWfRLvEuxHQxODs+QdN2mxMP1s1VWprHRR1jviXKwqvyekUsPMAqymg5uJlrGZVd+iOIU1Ts2EeRFqteJqjqpA64lEeUERG39Gp/p1/dsYK2L4AiDmZxcFlLq3AsGkeex4yOXwnqri4OmzDA2yDaCyaT4ivR4UQ1JNfn+vKP1Mc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WGci6GuM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WGci6GuM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53B691F000E9; Mon, 15 Jun 2026 16:40:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781541620; bh=vHty5W1wLqvhVA3NeN6Yxjt6mgiQU3qRuLgqXzcXCXU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=WGci6GuMdB0mo+nUhnNFMwQrhgskGSaFTvcoQLVPEZJJW73YRzmg7gIFIRLY0S8po 99tFzKc05fpHL/jgia6n2n9qZiymdXvJCVHpIQxcywP7m7CfWu1XSeVQVIugIUXQ3f tlSAJMjKeEAHbdbHUzd1T1E9p05hepObfQfc6WBcqtkdD9fcu5pMB3IjSOB4dqJSVU 8I2DuxyL9rdZOuWkXAujxIAREGV2OorauQfkMfcCbgMK7lskRRTVgzDY+8LrJXa5QN ttveTzCA5x8akcW40vqsv0JuullEh7MchJhB0hK9v7xR6/NAotAxakaZyON0f9phSu ValGSIoNExDSg== Date: Mon, 15 Jun 2026 12:40:13 -0400 From: Nathan Chancellor To: Jan Polensky Cc: hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, ojeda@kernel.org, peterz@infradead.org, jpoimboe@kernel.org, jbaron@akamai.com, aliceryhl@google.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, boqun@kernel.org, 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 Subject: Re: [PATCH v6 6/6] s390: Enable Rust support Message-ID: <20260615164013.GA249489@ax162> References: <20260608181451.3734956-1-japo@linux.ibm.com> <20260608181451.3734956-7-japo@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260608181451.3734956-7-japo@linux.ibm.com> Hi all, On Mon, Jun 08, 2026 at 08:14:51PM +0200, Jan Polensky wrote: > Enable building Rust code on s390 by wiring the architecture into the > kernel Rust infrastructure. > > Add s390 to the Rust arch support documentation, provide the s390 Rust > target and required compiler flags, and set the bindgen target for > arch/s390. Adjust the Rust target generation and minimum rustc version > gating so the s390 setup is handled explicitly. > > The Rust toolchain uses the "s390x" triple naming for the 64 bit target. > > Rust support is currently incompatible with CONFIG_EXPOLINE, which > relies on compiler support for the -mindirect-branch= and > -mfunction_return= options. Therefore, select HAVE_RUST only when > EXPOLINE is disabled. > > Acked-by: Miguel Ojeda > Acked-by: Heiko Carstens > Signed-off-by: Jan Polensky ... > diff --git a/arch/s390/Makefile b/arch/s390/Makefile > index 297976b41088..8b712cd85fcd 100644 > --- a/arch/s390/Makefile > +++ b/arch/s390/Makefile > @@ -35,25 +35,31 @@ KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) > KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) > KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_NO_ARRAY_BOUNDS),-Wno-array-bounds) > > +KBUILD_RUSTFLAGS += --target=s390x-unknown-none-softfloat -Zpacked-stack -Ctarget-feature=+backchain With Rust 1.96.0, I see the following warning several times when building Rust code in -next: warning: unstable feature specified for `-Ctarget-feature`: `backchain` | = note: this feature is not stably supported; its behavior can change in the future warning: 1 warning emitted I assume this is expected? If so, is there a way to silence this warning? -- Cheers, Nathan