From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by smtp.lore.kernel.org (Postfix) with ESMTP id D1C43EB64DD
	for <linux-kernel@archiver.kernel.org>; Tue,  8 Aug 2023 02:17:14 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S229634AbjHHCRN (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Mon, 7 Aug 2023 22:17:13 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46254 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229470AbjHHCRG (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 7 Aug 2023 22:17:06 -0400
Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA9D2183;
        Mon,  7 Aug 2023 19:17:04 -0700 (PDT)
Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140])
        (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
         key-exchange X25519 server-signature RSA-PSS (2048 bits))
        (No client certificate requested)
        by dfw.source.kernel.org (Postfix) with ESMTPS id 93CB562377;
        Tue,  8 Aug 2023 02:17:03 +0000 (UTC)
Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EEB8C433C8;
        Tue,  8 Aug 2023 02:16:59 +0000 (UTC)
Date:   Mon, 7 Aug 2023 22:16:58 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Florian Weimer <fweimer@redhat.com>,
        Marco Elver <elver@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Mark Rutland <mark.rutland@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, Miguel Ojeda <ojeda@kernel.org>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        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: <20230807221658.1d65ee28@gandalf.local.home>
In-Reply-To: <20230807123137.GA564305@hirez.programming.kicks-ass.net>
References: <20230804090621.400-1-elver@google.com>
        <87il9rgjvw.fsf@oldenburg.str.redhat.com>
        <20230807123137.GA564305@hirez.programming.kicks-ass.net>
X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, 7 Aug 2023 14:31:37 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> > that this is not a compilation for a module.  Otherwise modules built
> > with a compiler with __preserve_most__ attribute support are
> > incompatible with kernels built with a compiler without that attribute.  
> 
> We have a metric ton of options that can break module ABI. If you're
> daft enough to not build with the exact same compiler and .config you
> get to keep the pieces.

I believe there's enough checks for various compiler options in order to
enable features during the build that trying to load a module built with
another compiler is pretty much guaranteed to fail today.

-- Steve