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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2F2CDC432BE for ; Thu, 2 Sep 2021 10:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0ADB761059 for ; Thu, 2 Sep 2021 10:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242507AbhIBK4C (ORCPT ); Thu, 2 Sep 2021 06:56:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233761AbhIBK4A (ORCPT ); Thu, 2 Sep 2021 06:56:00 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29CFAC061575 for ; Thu, 2 Sep 2021 03:55:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=xRZI+EF7Bb02HlmhwHew/8U98K28CzYAN65inQkPbLA=; b=qgwUZG/cFtFFmCiMx1IAFICojh 7f+SYg96TVtEcKoLz294qVnFHbDWbjrJd2j+kqW133UQ+BxcHU2Au9HHWps9azq2TRqXcezFZ7Y5/ 08FUDzdXgjuyfo+hnflXXnTPqJfmqjxjJLo0SyuIuyhRsKkxdqtlZGiFJD/DTGrTQYNjgj0qTCUaK pHq3Vv9yJxKZAT147cfr5AFOtbjWgQ6HkB9UeGlsW0BprwWDk1WlyrQQSFkbZsuJkscbbTIPodzXA PXO7c2bR9km4keuJe333Kh3qIyfyojkCSiz1r6WuiDnf74Vf313kNBUfBO8aTfryLvkrKzwx4bwJ3 DpsGReSw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mLkIG-003OPI-OB; Thu, 02 Sep 2021 10:50:36 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 20D6B30029F; Thu, 2 Sep 2021 12:50:03 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 054722B1DE8E8; Thu, 2 Sep 2021 12:50:02 +0200 (CEST) Date: Thu, 2 Sep 2021 12:50:02 +0200 From: Peter Zijlstra To: Lai Jiangshan Cc: Joerg Roedel , Lai Jiangshan , linux-kernel@vger.kernel.org, Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Daniel Bristot de Oliveira , Brijesh Singh , Andy Shevchenko , Arvind Sankar , Chester Lin , Juergen Gross , andrew.cooper3@citrix.com Subject: Re: [PATCH 02/24] x86/traps: Move arch/x86/kernel/traps.c to arch/x86/entry/ Message-ID: References: <20210831175025.27570-1-jiangshanlai@gmail.com> <20210831175025.27570-3-jiangshanlai@gmail.com> <1f327579-e62a-df65-0763-e88243829db3@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1f327579-e62a-df65-0763-e88243829db3@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 02, 2021 at 05:21:51PM +0800, Lai Jiangshan wrote: > > > On 2021/9/2 16:09, Joerg Roedel wrote: > > On Wed, Sep 01, 2021 at 01:50:03AM +0800, Lai Jiangshan wrote: > > > arch/x86/entry/Makefile | 5 ++++- > > > arch/x86/{kernel => entry}/traps.c | 0 > > > arch/x86/kernel/Makefile | 5 +---- > > > 3 files changed, 5 insertions(+), 5 deletions(-) > > > rename arch/x86/{kernel => entry}/traps.c (100%) > > > > From looking over the patch-set I didn't spot the reason for putting the > > entry C code into traps.c. Can you explain that please? Otherwise I'd > > prefer to create a new file, like arch/x86/entry/entry64.c. > > > I agree, and I think Peter is handling it. I don't think I said that. I said I like the patches but there's a lot of scary code and details to review, which takes time. I've now done a second reading of the patches and provided some more feedback, but I'm very sure I didn't get to the scary details yet. One thing that got pointed out (by Andrew Cooper) is that by moving the whole SWAPGS trainwreck to C it becomes entirely 'trivial' to sneak in an 'accidental' per-cpu reference before having done the SWAPGS dance. I'm myself not (yet) convinced that's a good enough reason to leave it in ASM, but it does certainly need consideration.