From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E875CA0FE7 for ; Mon, 25 Aug 2025 19:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:Message-ID:References:In-Reply-To:Subject:CC:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=81ThnHgRyfJ3VAWTq+xvaABvLIKtK3i4qxFSEaYkKCo=; b=DvSw25sLyiCDTp4hddGcJezysn I3F8UP0gb07lEhC65mjBwprgwgevIjZSobZCMql7Wx3Lmd/ZxJOY2d6xVHoEAyDnu7YheyJ/PLxST 30Mep/rRCvnKtrOvq3mQbYL44G/kKJtrIzWNxCBp7Wd9O3aG2yV/WKz9qNVvs1huM2HipEl3K+kLg Hl2injthP/fjJmc+eURxYob4bnreoZJt1tZRQELVJ28UzoMrM/Xsok2sT7WPj16pIbSnFpqbPZKsL W4KyLMGFaWzg9T2bA1IcAtLOTh3A0j1hOolMOvyonpdq6tBfOCpl9juFzpEU8nM/jwKdOmzArz4gi E0kwAM2w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqcyB-00000009MJI-0wWo; Mon, 25 Aug 2025 19:35:07 +0000 Received: from mta.outflux.net ([2001:19d0:2:6:c0de:0:736d:7471] helo=smtp.outflux.net) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqcvO-00000009KgR-1h7C; Mon, 25 Aug 2025 19:32:15 +0000 Received: from auth (localhost [127.0.0.1]) (authenticated bits=0) by vinyl.outflux.net (8.15.2/8.15.2/Debian-10) with ESMTPSA id 57PJVcXW012364 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 25 Aug 2025 12:31:39 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=outflux.net; s=2016010; t=1756150300; bh=Cc0A7KST88BbLESFvBNiNEgFzJEi7Yi2EVmfXhRgL6M=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=dmm7Uk1rljY/b4/3j8njDIEy+Scks4cnfZAOL8qtbXCH9h9jV621co70Fuer5Vf17 2vNGEXeFRnmarqqQKCQXq3nlyBV+sTTzdmwDNFgEktyxTZkW7g83isIllAWQ5Jvik2 /8fn12aBvHvvu5EXYWBmhf7ySJSjrTUnGPHeNjnY= Date: Mon, 25 Aug 2025 15:31:34 -0400 From: Kees Cook To: Miguel Ojeda , Kees Cook CC: Peter Zijlstra , Sami Tolvanen , Linus Walleij , Mark Rutland , Puranjay Mohan , David Woodhouse , Jonathan Corbet , Nathan Chancellor , x86@kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org Subject: Re: [PATCH 5/5] kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI User-Agent: K-9 Mail for Android In-Reply-To: References: <20250825141316.work.967-kees@kernel.org> <20250825142603.1907143-5-kees@kernel.org> <202508250834.E2456B9@keescook> Message-ID: <9CCDBE93-7DBD-41D0-B9B6-05900F2AB1EE@outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-MIMEDefang-Filter: outflux$Revision: 1.316 $ X-HELO: [IPv6:::1] X-Scanned-By: MIMEDefang 2.83 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250825_123214_457925_1DE5E44C X-CRM114-Status: GOOD ( 13.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On August 25, 2025 1:00:22 PM EDT, Miguel Ojeda wrote: >On Mon, Aug 25, 2025 at 5:35=E2=80=AFPM Kees Cook wro= te: >> >> Yeah, that's a good idea=2E What the right way to do that? >> >> config CFI_CLANG >> bool "Use Clang's Control Flow Integrity (CFI)" >> depends on ARCH_SUPPORTS_CFI >> select CFI >> >> ? > >I don't recall what is the idiomatic solution for renames, but I >remember Linus talking about this topic and about avoiding losing old >values if possible (perhaps getting a new question in `oldconfig` is >OK as long as the `olddefconfig` respects the old value)=2E > >I think your suggestion above will still make it appear twice in >`menuconfig` -- there may be a way to play with visibility to make it >better=2E > >A simple possibility I can think of (assuming it works) is having the >CFI symbol for the time being introduced just as a `def_bool >CFI_CLANG` for a few releases so that people get the new one in their >configs=2E Ah, I think this works: config CFI_CLANG bool config CFI bool "=2E=2E=2E=2E" default CFI_CLANG I will add that for v2=2E -Kees --=20 Kees Cook