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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2F0D7C433E0 for ; Wed, 20 May 2020 17:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE179207D3 for ; Wed, 20 May 2020 17:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589994797; bh=aBnQahn6Rx4syCQPw6nXrqo1bJDUJ1S1WtEdZT9KUVU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=qnKRwpwwU0UENtTTLuooBnHTkFEzn4JbbiFnjSvs6Rk5PQRbUMOiclcw/zVpsNsIS 3aiQydvt32E11AfvPrA+6y6PwerdPG4SHL587iivbk60GKBfJYqE6GW/wpr9sTb/0S kqsLRAtbbt6aaRWM4nlU42b07Fahw1gDzHhzi84o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726957AbgETRNR (ORCPT ); Wed, 20 May 2020 13:13:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:59892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726691AbgETRNQ (ORCPT ); Wed, 20 May 2020 13:13:16 -0400 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A7E162070A for ; Wed, 20 May 2020 17:13:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589994796; bh=aBnQahn6Rx4syCQPw6nXrqo1bJDUJ1S1WtEdZT9KUVU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=rn6dTu/QCsIPsOlSXLkiFei4+NqNuuqFItyUj6DdLTF34ZlAaZDFIkQOMJQA7U+Nk oqNXL0qad5AFDjx7MV0m86sudtZbzrhw+JDDLoPLfl2W1um0wYcfyZR72QRKOzs63a HwcCIMSjA6Bram1Uq1Y2yu4M6c5cm0GG6pnDXEoI= Received: by mail-wm1-f42.google.com with SMTP id g14so483614wme.1 for ; Wed, 20 May 2020 10:13:15 -0700 (PDT) X-Gm-Message-State: AOAM533kyldfMU3mEyYOpGnolM+fIFCPwUHrSp8hpIinXoLFWTDzygA1 Rw5Z2qsLtfo+HadusBe8IotuUJDVTVo3M/bnmB++fw== X-Google-Smtp-Source: ABdhPJyqE73tj45GgRcuRENdcBFo/oFYikprLfZkfLqP5QSlvVEuV3i4EoHFUJ9qCHMejxr93zIxieuEnsbiXY8vsqs= X-Received: by 2002:a1c:9893:: with SMTP id a141mr3075808wme.176.1589994794103; Wed, 20 May 2020 10:13:14 -0700 (PDT) MIME-Version: 1.0 References: <20200515234547.710474468@linutronix.de> <20200515235127.996226788@linutronix.de> <87lflm4owm.fsf@nanos.tec.linutronix.de> In-Reply-To: <87lflm4owm.fsf@nanos.tec.linutronix.de> From: Andy Lutomirski Date: Wed, 20 May 2020 10:13:02 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch V6 36/37] x86/entry: Move paranoid irq tracing out of ASM code To: Thomas Gleixner 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)" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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.