Received: by 2002:a25:8b91:0:0:0:0:0 with SMTP id j17csp2008131ybl; Thu, 30 Jan 2020 09:45:26 -0800 (PST) X-Google-Smtp-Source: APXvYqwChFI3gX5sF3ZIBhhC3ncqLzskC4r7t7pIjHKx+DRZGMifAXVG4pGqIrmnRqRXc20TbtN/ X-Received: by 2002:aca:1913:: with SMTP id l19mr3505969oii.47.1580406326855; Thu, 30 Jan 2020 09:45:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1580406326; cv=none; d=google.com; s=arc-20160816; b=QgTgN0vlGr4fAkEaGGYeit2sYu2G+Z+/7CLpSliQqquPjGoIvcaR+vHC50eV4iVz/j NrXIh13hwRC3JL+ZpqE1/LKMNAOL9HOJzKYD+bmQuBpFTbdb7EZ68g5yCkeHgUMajleS jOGwGjZQPidx1XmMLeihzDNsMJWLwtfpTghFsOyIWT6nPT1on5MKL8RLe3zRuOcuAsS9 oY7cwmPKBxPCD7LKgJLYTFHetSyFjqKbBA7Rt5Es5EoeBXPEYhh1MTldZiy0QQJUc+uX JwW1oBV8PkJOqGZn18A7Qqy3hX4Kp3wNZ1VCb2DXmdA6VGTBbu9IGiFGWHdKDz7Xp0SN CFfg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-transfer-encoding:content-disposition:mime-version :references:message-id:subject:cc:to:from:date; bh=YYWH/8zoM+qCaVPvt0KIQMG/ug0Dp2sTsg6+3w48d8w=; b=FKgI4EW6I0hh6Btj8vkXrt/d5EklsTNMFXWSMYgbd3GLLlkLbFYKv0Xa1/kGtmFvJG s7xMcN3GZTW45INTlWX1vOKYyIG6EGlC9HQXoubDWR0VPYtritLgvcczHC4DPiCjiFAq W1DCSQItC3+jPt3akgW8nCEjSzJZDX8CYaMmYXzo7KIN8wTON9z7Ncp1sDNQB1bd/LkI 9lNlvo7H/QzQjtKvBqLsvLqhpjHthtXLptgp3XAWIXF6814Dk2v99T0LWEXKUZBlg5L+ JjHfBHNRJt+8ZuIT3yYPfCiCUpOvmwY0E2+5gArMIanpCGyO5l2g6oK/J9/6zZ5XQmHN vgDg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id k13si2996161oij.118.2020.01.30.09.45.14; Thu, 30 Jan 2020 09:45:26 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727405AbgA3RjO (ORCPT + 99 others); Thu, 30 Jan 2020 12:39:14 -0500 Received: from mx2.suse.de ([195.135.220.15]:38162 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727247AbgA3RjO (ORCPT ); Thu, 30 Jan 2020 12:39:14 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 9ADC5AF6D; Thu, 30 Jan 2020 17:39:12 +0000 (UTC) Date: Thu, 30 Jan 2020 18:39:10 +0100 From: Borislav Petkov To: Linus Torvalds Cc: "Luck, Tony" , Ingo Molnar , Linux Kernel Mailing List , Thomas Gleixner , Borislav Petkov , Peter Zijlstra , Andrew Morton Subject: Re: [GIT PULL] x86/asm changes for v5.6 Message-ID: <20200130173910.GK6684@zn.tnic> References: <20200128165906.GA67781@gmail.com> <20200129132618.GA30979@zn.tnic> <20200129170725.GA21265@agluck-desk2.amr.corp.intel.com> <20200129183404.GB30979@zn.tnic> <20200130085134.GB6684@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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 Thu, Jan 30, 2020 at 07:27:28AM -0800, Linus Torvalds wrote: > Fair enough. Let's not complicate things just to avoid a few nops. Yeah, judging by the frequency this keeps popping up, we might end up doing proper insn parsing for the alternatives soon. :) > That does make me wonder about RIP-relative addressing in alternatives > too. Particularly anything where we let gcc pick addressing modes. I > guess we don't have any, but maybe this branch issue and possible RIP > addressing is something that objtool could be taught to warn about? Yeah, makes sense. It would help if one slaps a relative JMP as *not* the first insn in an alternatives replacement and the build to warn that it can't work. Lemme go stare at objtool. -- Regards/Gruss, Boris. SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg