From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3C759322A00; Thu, 26 Mar 2026 02:42:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774492955; cv=none; b=JVZzNnCJh1X5P5+BPaEoepCHsv1WZ191b8ry6zteCDWvapuz2Q0zkQU6QVjUx0gaSVQIAA3nq85rI5uNuOJF1QUNHMLQWz7S7V0mD7RsbA5y4H0qSgFLshIdWPCdyNkWjvpzmMFjicTDRGvJ3yzIi2RQVqYxoEmYV+gWY5BmRwA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774492955; c=relaxed/simple; bh=zQaAoby1LL5qtX0PbqpV15cjdPtMgN1fWIPjYj6cHHc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=U4V1yX3TKnJcSrfA2ZQ/oJ/M1inSBlFmHIl8JVHwnwmL6pzFFuZD6rYsZaYzOi88Di2s0mueZoGXoET9T0JSBMwP1pLd1LW2GcGsiKv0jSTHyFglVg61eJYIkGkcscacMNt/ps+4g3a70BUrjlgzbZMj/hKlaVbKMD3aeoV1sUE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S8zGn/i+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S8zGn/i+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB208C4CEF7; Thu, 26 Mar 2026 02:42:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774492954; bh=zQaAoby1LL5qtX0PbqpV15cjdPtMgN1fWIPjYj6cHHc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=S8zGn/i+Spyx9XA47CpCu/vQAg2jkahFRQzQumLqtrDpCNSJTCj03aAkEznFHIBqF BHqQtK9yH0jlsDRFhpqINdr/8qKOFZZ33DoLjiHS1rBQN8A7rN6+cd4XspEv86q4aw fX5sdIVSmixq08mIaV+WQ20CFRO/xOqtaVcHBACJLjdgVgNEAW/1eD2ppZ4E8Sqo34 KMBXF5A5vLLXjt9vVzfBdhnIBFejLTjFksFyWA19+Dk1JNuNC3tUVbCRh3Eo+Ed2YP iTNr+GVTtwyhLeEY70H14v74c5VO6yI6pMXy8ExXxlKbsKAbxCmXLa/pnbG4dlN+CH y4s8jAUhtp60A== Date: Wed, 25 Mar 2026 19:42:26 -0700 From: Nathan Chancellor To: Miguel Ojeda Cc: Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , David Gow , Russell King , Richard Weinberger , Anton Ivanov , Johannes Berg , aliceryhl@google.com, linux-um@lists.infradead.org, llvm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, a.hindborg@kernel.org, acourbot@nvidia.com, akpm@linux-foundation.org, bjorn3_gh@protonmail.com, boqun.feng@gmail.com, dakr@kernel.org, gary@garyguo.net, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lossin@kernel.org, mark.rutland@arm.com, mmaurer@google.com, nicolas.schier@linux.dev, peterz@infradead.org, rust-for-linux@vger.kernel.org, tmgross@umich.edu, urezki@gmail.com, will@kernel.org Subject: Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO Message-ID: <20260326024226.GB2302780@ax162> References: <20260203-inline-helpers-v2-0-beb8547a03c9@google.com> <20260322192159.88138-1-ojeda@kernel.org> Precedence: bulk X-Mailing-List: linux-kbuild@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: <20260322192159.88138-1-ojeda@kernel.org> On Sun, Mar 22, 2026 at 08:21:59PM +0100, Miguel Ojeda wrote: > - Clang passes `-Werror=unused-command-line-argument`, which means > under arm (i.e. 32-bit) we get: > > clang: error: argument unused during compilation: '-U arm' [-Werror,-Wunused-command-line-argument] > > And under UML I see: > > clang: error: argument unused during compilation: '-I ./arch/um/include/shared' [-Werror,-Wunused-command-line-argument] > clang: error: argument unused during compilation: '-I ./arch/x86/um/shared' [-Werror,-Wunused-command-line-argument] > clang: error: argument unused during compilation: '-I ./arch/um/include/shared/skas' [-Werror,-Wunused-command-line-argument] > > So we would need e.g. `-Wno-unused-command-line-argument` there > close to the `-Wno-override-module` one, unless Kbuild or > ClangBuiltLinux thinks it is important to keep it for this case. No, I don't think it is worth trying to make -Wunused-command-line-argument work for this command. Just disable it. This mirrors what is being done for cmd_cc_o_bc in the distributed ThinLTO: https://lore.kernel.org/20260316212930.120438-3-xur@google.com/ > On the other hand, regardless of whether we fix this (and another > issue in a separate email found thanks to the UML build), we could > instead add `depends on` listing explicitly the architectures where > this is going to be actually tested. That way maintainers can decide > whether they want to support it when they are ready. Thoughts? > > Cc'ing Nathan, Nicolas, Nick, Bill, Justin, David, UML, ARM. 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. > - If we use the `.bc` extension, we need to add a `.gitignore` for > `.bc` files, and an exception for `kernel/time/timeconst.bc`. > > I guess we will not have too many `bc` scripts in the future for > that to be a problem. On the other hand, we have the chance to use > another extension (either for LLVM bitcode or for `bc` scripts). > > But please let me know on e.g. the Kbuild side if someone has > concerns... 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. Cheers, Nathan