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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 6E6C9C2D0F6 for ; Tue, 12 May 2020 16:28:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CD9F206B8 for ; Tue, 12 May 2020 16:28:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="DhAhB8v+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728801AbgELQ2z (ORCPT ); Tue, 12 May 2020 12:28:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725851AbgELQ2w (ORCPT ); Tue, 12 May 2020 12:28:52 -0400 X-Greylist: delayed 4402 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 12 May 2020 09:28:52 PDT Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14D0DC061A0C; Tue, 12 May 2020 09:28:52 -0700 (PDT) Received: from zn.tnic (p200300EC2F0A9D0059BB7FCAE11E2EA0.dip0.t-ipconnect.de [IPv6:2003:ec:2f0a:9d00:59bb:7fca:e11e:2ea0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 935741EC0299; Tue, 12 May 2020 18:28:50 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1589300930; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=jfdRhXHPFSXx8Q5aS323J6F+OYj8FS8BGUJyQM6iM68=; b=DhAhB8v+Voi3PoHmOwXGeE9dEEdWM7Lppt80ZWH3Ep59LXOlnXJB9f63UvLzLtZLrO5lCd EnTSzz72STpeA4rwayxZeH8F23977zQW0UELu1jtXrdF1PBWsR/jXJhSOXVx0RWcZDNOIM pxsMg496T/+kff6wgORL9Wu4foBdJ7M= Date: Tue, 12 May 2020 18:28:45 +0200 From: Borislav Petkov To: Uros Bizjak Cc: LKML , linux-tip-commits@vger.kernel.org, "H. Peter Anvin (Intel)" , "Peter Zijlstra (Intel)" , x86 Subject: Re: [tip: x86/cpu] x86/cpu: Use INVPCID mnemonic in invpcid.h Message-ID: <20200512162845.GC6859@zn.tnic> References: <20200508092247.132147-1-ubizjak@gmail.com> <158929264101.390.18239205970315804831.tip-bot2@tip-bot2> <20200512151522.GB6859@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 12, 2020 at 05:54:49PM +0200, Uros Bizjak wrote: > Symbolic operands are agnostic to the position in the asm clause, so > it really doesn't matter much. It just doesn't feel right, when other > cases follow different order. > > > $ diff -suprN /tmp/before /tmp/after > > Files /tmp/before and /tmp/after are identical > > Sure, otherwise assembler would complain. > > > Makes sense? > > Well, I don't want to bikeshed around this anymore, so any way is good. Look at it this way: the symbolic operand names feature has made inline assembly *orders* of magnitude more readable than what it was before. Kernel folks, including myself, have stumbled upon the question which operand is which, on a regular basis and having the operand names there makes reading the inline asm almost trivial. So while we should not convert wholesale, I think we should aim to gradually convert those other cases to the a-lot-more readable variant with symbolic operand names. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette