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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B7E5C433DF for ; Wed, 29 Jul 2020 18:11:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63D4F2075D for ; Wed, 29 Jul 2020 18:11:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727908AbgG2SLv (ORCPT ); Wed, 29 Jul 2020 14:11:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726365AbgG2SLv (ORCPT ); Wed, 29 Jul 2020 14:11:51 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF3A6C061794 for ; Wed, 29 Jul 2020 11:11:50 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 0636728EB45 From: Gabriel Krisman Bertazi To: Andy Lutomirski Cc: Peter Zijlstra , Christoph Hellwig , Thomas Gleixner , Kees Cook , X86 ML , LKML , kernel@collabora.com Subject: Re: [PATCH 2/6] arch: x86: Wrap TIF_IA32 checks Organization: Collabora References: <20200728202229.1195682-1-krisman@collabora.com> <20200728202229.1195682-3-krisman@collabora.com> <878sf3j5cl.fsf@collabora.com> Date: Wed, 29 Jul 2020 14:11:44 -0400 In-Reply-To: (Andy Lutomirski's message of "Tue, 28 Jul 2020 22:09:26 -0700") Message-ID: <874kpqjin3.fsf@collabora.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andy Lutomirski writes: > On Tue, Jul 28, 2020 at 9:46 PM Gabriel Krisman Bertazi > wrote: >> >> Andy Lutomirski writes: >> >> > On Tue, Jul 28, 2020 at 1:22 PM Gabriel Krisman Bertazi >> > wrote: >> >> >> >> In preparation to remove TIF_IA32, add wrapper that check the process >> >> has IA32 ABI without using the flag directly. >> > >> > Thank you for doing this, but let's please do it right. There is, >> > fundamentally, no such thing as a "process with IA32 ABI". >> >> Hi Andy, >> >> Thanks a lot for your review. >> >> As you can see, I'm learning my way here. Can you clarify "there is no >> such a thing as a 'process with IA32 ABI'"? I'm not sure if I confused >> the terminology or if (more worrisome for me) I got the concepts wrong. >> >> My understanding is that TIF_IA32 marks a thread that is running under >> the 32-bit compat mode, which would be running a 32-bit process (as in >> compiled with -m32, for instance), while TIF_X32 marks a process running >> under the X32 ABI. Each process would have only one of these >> "personalities". This is what I meant by a process with IA32 ABI (which >> is wrong in any case). Is there more to it, or is the problem the >> terminology I used? > > There's more to it. Thanks again for the explanation! >> I don't have any comments on the other things you mentioned, except that >> I need to go through them and better understand your suggestions. Would >> you prefer me to rework this patch series with what you suggested or is >> this something you want to take over and do yourself? Both ways are >> fine by me. > > Please rework it :) I have seriously limited bandwidth right now. Will do. -- Gabriel Krisman Bertazi