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 8B120330B30; Tue, 28 Oct 2025 17:52:50 +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=1761673970; cv=none; b=ANZyKPbo2JBtarUbnzf1ihzwEKbznHlMHcj8sp+sctqQmfATtgkAVU4tITkylwMc/5/rCnbhI8mCthPCDXiV13wzVwvS4Q9szrQQOLr+yZnifR2ISV9hermbPyVOZbLZAhCRhvpj6+gAKjv1yc6KhNYekhiNMX+hTu9gRoiOKjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761673970; c=relaxed/simple; bh=Moq064DwQdSS6qTOYeb42y6SY5Kr7+VDV6iVv9m8xBQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=k+tkhPbNb/iOAonXoj+tJJyonWWKKSwqtFT5VNwTM9FXzyAkaxOBIepvPQB0tTZkWcdRuaTcGWNHmnjmCcabK1mDuiikuKg6Uxk0Lu42cDlBV65XkgK2qczX85t08iPbFsGHZa/h/HmRwcyukiYud5ZR9TGiyUBFPOSTXrGN66U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jcqim24v; 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="jcqim24v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F24AC4CEE7; Tue, 28 Oct 2025 17:52:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761673970; bh=Moq064DwQdSS6qTOYeb42y6SY5Kr7+VDV6iVv9m8xBQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jcqim24vkU/lNUAwQO+ySvG//0jPahaWXHXgAox1AfcfBdPxJPT3NTHoljAfIQYGt MaBdO4/AgJqqdZ1woP/x1NfOVWC8yunhevd9di6JM/iv1H0gJ6eqPQxFXzoUHGJ04D scy+VnPKywP5ILoZhGpWVOIRAO5XcBMvpBvKhPZDzpq2NhBpAuqqbUUowFnp8a96KC 4rlVUHFdp71lSRoL2i/I5XpYnhYsLp/3LnWR1D0bbTjC0rcdQNHh9Sjo+1WtXiSX0P yVN+0IeIxy/79PMPodDKBtZBZNCwUeLSgW2NbN9RZOlwk167bZu+8Er41Ugle2BBsI Z3n/fBO32uYAA== Date: Tue, 28 Oct 2025 10:52:43 -0700 From: Nathan Chancellor To: Linus Walleij Cc: Sami Tolvanen , Kees Cook , Alexander Lobakin , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Nick Desaulniers , Bill Wendling , Justin Stitt , Russell King , Tony Nguyen , Michal Kubiak , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org Subject: Re: [PATCH 2/3] ARM: Select ARCH_USES_CFI_GENERIC_LLVM_PASS Message-ID: <20251028175243.GB1548965@ax162> References: <20251025-idpf-fix-arm-kcfi-build-error-v1-0-ec57221153ae@kernel.org> <20251025-idpf-fix-arm-kcfi-build-error-v1-2-ec57221153ae@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Oct 27, 2025 at 11:56:21PM +0100, Linus Walleij wrote: > On Mon, Oct 27, 2025 at 4:54 PM Sami Tolvanen wrote: > > Instead of working around issues with the generic pass, would it make > > more sense to just disable arm32 CFI with older Clang versions > > entirely? Linus, any thoughts? > > We have people using this with the default compilers that come with > Debiand and Fedora. I would say as soon as the latest release of > the major distributions supports this, we can drop support for older > compilers. Okay, I think that is reasonable enough. This is not a very large workaround and I do not expect these type of workarounds to be necessary frequently so I think it is worth keeping this working if people are actually using it. That means we could mandate the backend version of kCFI for ARM with Debian Forky in 2027. Cheers, Nathan