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 27C3EC433EF for ; Mon, 2 May 2022 19:56:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID: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=LGcWqLaeYkgYEInqLqtVMMkDs+nIh5OyrLZwSVbnfdY=; b=ebTvJAx4ob/fow 4s/WzCKoQdZBhyv8ojGsuMoMzsn94yzPm7OQrmA6Nxcz5HrFnjcsjx+X8MNBIq2DJzUsbY//d7eDQ 2ef2nvBY3qyu5cOMxkG/C9ZPmm0rn93cY2t1bdB+VNranxs2BEasfNU0wu7mowbLFrbOm+298UK3t w4pes7bAvNgk0CHUC+fdcBgpK9/NTu59lQvRYN3o9FjN/QAj85PblB7iM+/JGy4ZD13B3ASp0BAdR WMLgeRmedO8OH7GtSIUdcnLJoK+0yQlkfmsvxr2mrkr58H6QsZKXlZ3Ayf2NtZ0EukcPTIl/V6UM7 1b4VvgiKe2/aiaE2KO0g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlc8z-002Rex-35; Mon, 02 May 2022 19:55:41 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlc8w-002Rec-VT for linux-arm-kernel@bombadil.infradead.org; Mon, 02 May 2022 19:55:38 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=mYYa7YhSPmVPESGC3WBfSUVLu7/5dL6ovKiS3tnTNxc=; b=X7JjkI1eS+hZwlLL/I9p7ec0h2 UeIxqvrdiJt3meq6ElbsNEDYIxW+qZz/j2FrSu6coXltcfr4QtTMMPFDzslv9IR5A31jl1ddBKnH9 c2qsGdbgoQzF9iywxqp5QHtMYcYLEB3+RVk8mUsIOTnJ93L7VRDhLz56q/kJE1S8EfyygaZ+EPJH4 +lUKye+VxqZ8KUh1eKBescSHXrCybAweDQoUoV1TG8LbXYRpZEdQGzvMqMTJ67eTO75Z/LyqmGrAJ WIdEZp2LKR7NJxMrEW0UmH4MNpVWroXNW+J0b79QIxFrPP2W8RHSAR29nZiASkc9sS+Ga1qVVPW+d 6RQX6kKQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlc8m-00AZWD-7z; Mon, 02 May 2022 19:55:28 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 772E030017D; Mon, 2 May 2022 21:55:25 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5223120288CEB; Mon, 2 May 2022 21:55:25 +0200 (CEST) Date: Mon, 2 May 2022 21:55:25 +0200 From: Peter Zijlstra To: Sami Tolvanen Cc: Kees Cook , Mark Rutland , Josh Poimboeuf , Will Deacon , Catalin Marinas , Nathan Chancellor , Nick Desaulniers , Joao Moreira , Sedat Dilek , Steven Rostedt , LKML , X86 ML , linux-hardening@vger.kernel.org, linux-arm-kernel , llvm@lists.linux.dev Subject: Re: [RFC PATCH 00/21] KCFI support Message-ID: References: <20220429203644.2868448-1-samitolvanen@google.com> <202204291545.47C6A97EA2@keescook> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, May 02, 2022 at 08:22:57AM -0700, Sami Tolvanen wrote: > > Anyway, I think I hate that __builtin, I'd *much* rather see a variable > > attribute or qualifier for this, such that one can mark a function > > pointer as not doing CFI. > > > > I simply doesn't make sense to have a builtin that operates on an > > expression. The whole thing is about indirect calls, IOW function > > pointers. > > I also thought an attribute would be more convenient, but the compiler > folks prefer a built-in: > > https://reviews.llvm.org/D122673 That seems to mostly worry about C++ things (overload sets, template specialization, name mangling) we kernel folks don't seem to much care about. I'll stick with saying type system makes more sense to me though. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel