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 DF8F1C00528 for ; Mon, 7 Aug 2023 15:06:56 +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=YzhriQ+e2Z+/L5yR75H5t1xqXRHICPOs4lOBxeMRR74=; b=DjcWgl1vxqbxLw mpiDS4TzEzu79U+0gga/O1n4H5Vh6QruuWtrqt6y+JPmk/EDAbR7fZgW4/0r3pekxUmrNSeTueu+u HwxCIE/ODxWSLfSehnZYd0zd/i57syhiRT2YtBjZ7b7U6Y6yJ8/KXhg5DOfr/zgRP/FUeVs773VKF ePu2gtgmcjFVzxyvUxJWVXtUEFT+7BZKgADggUAgoub5O4bk25YZTMK0ouq1L+UYR0fuPQn/enaJ1 P1jbpm397gJZ4BgKMp/HMiZdB3V7+1FVe8QUHiIN7LQ6O/kgqsuIIzqOUYgiKW6tIAoaCnNscKXxG AM8iVXa0idahjKkPFzVg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qT1oT-0000zd-09; Mon, 07 Aug 2023 15:06:29 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qT1oR-0000xi-00 for linux-arm-kernel@bombadil.infradead.org; Mon, 07 Aug 2023 15:06:27 +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=zOz2Sl6sETEspUjEfHGN0Doq9IKMqDh9com1ZKQ2ccQ=; b=L84dIEOGbchqXHanFmF61ALhon HTWLrRNFiG+i4OH+sZd6IzaTjVs+X08wTRaG4WbHVcPFUkStJ0VR4FmmWq3yvmQrDyiDSu7t8tALr exouGMBNLEgZ/RkcFRxuAgG0xD3zMAPNH33IuJHyyZ1AMUkM74PWftDLKPgQJdBaWtARbr/k+jncm 61WcqynycYOSanAel3SSyem+JxNGHNErJu5tPC6tLnrhAH0AtnGZ3OVSTZyRM/ZqW7pFALUCczdMN TLr6fnqW213OqECH5Z8FjGXOEYmfuFb0j+yJKe+QdQRho8yrtPhLfOk5fjTrtp5WfbXpmuwO669i4 EP0Y5+zA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qT1oI-003w69-37; Mon, 07 Aug 2023 15:06:19 +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)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 6B7E7300473; Mon, 7 Aug 2023 17:06:17 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4840C2028F056; Mon, 7 Aug 2023 17:06:17 +0200 (CEST) Date: Mon, 7 Aug 2023 17:06:17 +0200 From: Peter Zijlstra To: Florian Weimer Cc: Marco Elver , Andrew Morton , Kees Cook , Guenter Roeck , Mark Rutland , Steven Rostedt , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Nathan Chancellor , Nick Desaulniers , Tom Rix , Miguel Ojeda , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Dmitry Vyukov , Alexander Potapenko , kasan-dev@googlegroups.com, linux-toolchains@vger.kernel.org Subject: Re: [PATCH v2 1/3] compiler_types: Introduce the Clang __preserve_most function attribute Message-ID: <20230807150617.GB569857@hirez.programming.kicks-ass.net> References: <20230804090621.400-1-elver@google.com> <87il9rgjvw.fsf@oldenburg.str.redhat.com> <87pm3zf2qi.fsf@oldenburg.str.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87pm3zf2qi.fsf@oldenburg.str.redhat.com> 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, Aug 07, 2023 at 02:36:53PM +0200, Florian Weimer wrote: > I think the GCC vs Clang thing is expected to work today, isn't it? > Using the Clang-based BPF tools with a GCC-compiled kernel requires a > matching ABI. Nope, all bets are off. There is no module ABI, in the widest possible sense. There's all sorts of subtle breakage, I don't remember the exact details, but IIRC building the kernel with a compiler that has asm-goto-output and modules with a compiler that doesn't have it gets you fireworks. We absolutely do even bother tracking any of this. There's also things like GCC plugins, they can randomly (literally in the case of struct randomization) change things around that isn't compatible with what the other compiler does -- or perhaps even a later version of the same compiler. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel