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=-7.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7D3DCC35666 for ; Fri, 21 Feb 2020 20:23:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F5572072C for ; Fri, 21 Feb 2020 20:23:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="glnyFpsY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728249AbgBUUXQ (ORCPT ); Fri, 21 Feb 2020 15:23:16 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:40184 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726483AbgBUUXP (ORCPT ); Fri, 21 Feb 2020 15:23:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=9eah5mmtKLlA+R3XKIogLnPb4pPWtnReB1crMdBWtYc=; b=glnyFpsYL1aEqrd70xvIyYQzNb 9tfkpuBvQHr6ir6X/Bv877cfG0gKuxQp7ihwG56BqSZYKGuYrdivuD3j/wnNato2VV9WpqTQ4MGI9 oITRq7eJ21VtURkWM3MmhRkXIQpXa8C/7Dq2i3D9dq5EHLsUmB+xDsrRy4z+0PXCQZOKeO1rozvUQ UTTDIU33rVEsl4l6PSrhdHs8/0SauKfDyJ3Gntc1lNjxH15+G2uNx004rB6EowNvADQCujEvx5FVe pK4hq9+IfPfdk8iWu64vzKrVDvEYgmrKaV4eQrlo/8Fw+ROqKffUO3T61YMKU9f/ALCXanZmh7wa8 Ggn3EtDw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j5Ep0-0002E7-Dq; Fri, 21 Feb 2020 20:22:50 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D7C4130008D; Fri, 21 Feb 2020 21:20:53 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9CE7D209DB0F7; Fri, 21 Feb 2020 21:22:46 +0100 (CET) Date: Fri, 21 Feb 2020 21:22:46 +0100 From: Peter Zijlstra To: Andy Lutomirski Cc: LKML , linux-arch , Steven Rostedt , Ingo Molnar , Joel Fernandes , Greg KH , gustavo@embeddedor.com, Thomas Gleixner , paulmck@kernel.org, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Tony Luck , Frederic Weisbecker , Dan Carpenter , Masami Hiramatsu Subject: Re: [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter() Message-ID: <20200221202246.GA14897@hirez.programming.kicks-ass.net> References: <20200221133416.777099322@infradead.org> <20200221134215.328642621@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 Fri, Feb 21, 2020 at 11:05:36AM -0800, Andy Lutomirski wrote: > > - /* > > - * Use ist_enter despite the fact that we don't use an IST stack. > > - * We can be called from a kprobe in non-CONTEXT_KERNEL kernel > > - * mode or even during context tracking state changes. > > - * > > - * This means that we can't schedule. That's okay. > > - */ > > - ist_enter(regs); > > + nmi_enter(); > > I agree with the change, but some commentary might be nice. Maybe > copy from here: > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/idtentry&id=061eaa900b4f63601ab6381ab431fcef8dfd84be Fair enough; I'll add something to #DB and #BP for that.