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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 81099C433DF for ; Wed, 20 May 2020 18:33:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FCAC20671 for ; Wed, 20 May 2020 18:33:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726851AbgETSdi (ORCPT ); Wed, 20 May 2020 14:33:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726510AbgETSdi (ORCPT ); Wed, 20 May 2020 14:33:38 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3661AC061A0E for ; Wed, 20 May 2020 11:33:38 -0700 (PDT) Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jbTWj-00006C-6t; Wed, 20 May 2020 20:33:13 +0200 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id 8BD49100C99; Wed, 20 May 2020 20:33:12 +0200 (CEST) From: Thomas Gleixner To: Andy Lutomirski Cc: Andy Lutomirski , LKML , X86 ML , "Paul E. McKenney" , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon , Tom Lendacky , Wei Liu , Michael Kelley , Jason Chen CJ , Zhao Yakui , "Peter Zijlstra \(Intel\)" Subject: Re: [patch V6 36/37] x86/entry: Move paranoid irq tracing out of ASM code In-Reply-To: References: <20200515234547.710474468@linutronix.de> <20200515235127.996226788@linutronix.de> <87lflm4owm.fsf@nanos.tec.linutronix.de> Date: Wed, 20 May 2020 20:33:12 +0200 Message-ID: <874ksawj6f.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andy Lutomirski writes: > On Wed, May 20, 2020 at 8:17 AM Thomas Gleixner wrote: >> >> Andy Lutomirski writes: >> >> > On Fri, May 15, 2020 at 5:11 PM Thomas Gleixner wrote: >> > >> > I think something's missing here. With this patch applied, don't we >> > get to exc_debug_kernel() -> handle_debug() without doing >> > idtentry_enter() or equivalent? And that can even enable IRQs. >> > >> > Maybe exc_debug_kernel() should wrap handle_debug() in some >> > appropriate _enter() / _exit() pair? >> >> I'm the one who is missing something here, i.e. the connection of this >> patch to #DB. exc_debug_kernel() still looks like this: >> >> nmi_enter_notrace(); >> handle_debug(regs, dr6, false); >> nmi_exit_notrace(); >> >> Confused. >> > > Hmm. I guess the code is correct-ish or at least as correct as it > ever was. But $SUBJECT says "Move paranoid irq tracing out of ASM > code" but you didn't move it into all the users. So now the NMI code > does trace_hardirqs_on_prepare() but the #DB code doesn't. Perhaps > the changelog should mention this. Duh. I simply missed to add it. > exc_kernel_debug() is an atrocity. Every now and then I get started > on cleanup it up and so far I always get mired in the giant amount of > indirection. > > So Acked-by: Andy Lutomirski if you write a credible > changelog.