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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 B43C5C433F5 for ; Fri, 7 Sep 2018 08:00:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78D61206BB for ; Fri, 7 Sep 2018 08:00:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78D61206BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728114AbeIGMkb (ORCPT ); Fri, 7 Sep 2018 08:40:31 -0400 Received: from mail.skyhub.de ([5.9.137.197]:34566 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726596AbeIGMk2 (ORCPT ); Fri, 7 Sep 2018 08:40:28 -0400 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 0duh6I7kWaqM; Fri, 7 Sep 2018 10:00:43 +0200 (CEST) Received: from zn.tnic (p200300EC2BCC4300329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2bcc:4300:329c:23ff:fea6:a903]) (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 68ADC1EC00F4; Fri, 7 Sep 2018 10:00:43 +0200 (CEST) Date: Fri, 7 Sep 2018 10:00:41 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: x86@kernel.org, LKML , Dave Hansen , Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Linus Torvalds , Josh Poimboeuf , Joerg Roedel , Jiri Olsa , Andi Kleen , Peter Zijlstra Subject: Re: [PATCH v2 2/3] x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space Message-ID: <20180907080041.GA12849@zn.tnic> References: <08e769a0023dbad4bac6f34f3631dbaf8ad59f4f.1536015544.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <08e769a0023dbad4bac6f34f3631dbaf8ad59f4f.1536015544.git.luto@kernel.org> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 03, 2018 at 03:59:43PM -0700, Andy Lutomirski wrote: > In the non-trampoline SYSCALL64 path, we use a percpu variable to > temporarily store the user RSP value. Instead of a separate > variable, use the otherwise unused sp2 slot in the TSS. This will > improve cache locality, as the sp1 slot is already used in the same > code to find the kernel stack. It will also simplify a future > change to make the non-trampoline path work in PTI mode. > > Signed-off-by: Andy Lutomirski > --- > arch/x86/entry/entry_64.S | 16 +++++++++------- > arch/x86/include/asm/processor.h | 6 ++++++ > arch/x86/kernel/asm-offsets.c | 3 ++- > arch/x86/kernel/process_64.c | 2 -- > arch/x86/xen/xen-asm_64.S | 8 +++++--- > 5 files changed, 22 insertions(+), 13 deletions(-) Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.