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=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 7D90DC28CBC for ; Wed, 6 May 2020 08:15:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58552206E6 for ; Wed, 6 May 2020 08:15:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="E5Uf9V9X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728477AbgEFIPA (ORCPT ); Wed, 6 May 2020 04:15:00 -0400 Received: from mail.skyhub.de ([5.9.137.197]:43578 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728296AbgEFIPA (ORCPT ); Wed, 6 May 2020 04:15:00 -0400 Received: from zn.tnic (p200300EC2F069600BCEB9C28D5742179.dip0.t-ipconnect.de [IPv6:2003:ec:2f06:9600:bceb:9c28:d574:2179]) (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 3741B1EC0347; Wed, 6 May 2020 10:14:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1588752898; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=s5RV4o9+46GjRd6gshEq1QxtSsdTZ2fduNFg5bSsMV4=; b=E5Uf9V9XzZLS67J1Bqk811UzOJlTMg5M2KNVyQG3LgEvDqsOoUugPOz7QJASIOTKUA2JPp ZwZciHNalYt2+yAElzuSBjRgnpMPyk0/56BKkLy6CdVS93vD10JCL3H73+gvj2vVLQG2Rb QuEfkvBR0zly36F/hfMV9+wq0k2dRY4= Date: Wed, 6 May 2020 10:14:54 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: LKML , x86@kernel.org, "Paul E. McKenney" , Andy Lutomirski , 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 , "Peter Zijlstra (Intel)" Subject: Re: [patch V4 part 1 02/36] x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area Message-ID: <20200506081454.GA25532@zn.tnic> References: <20200505131602.633487962@linutronix.de> <20200505134058.272448010@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200505134058.272448010@linutronix.de> 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 Tue, May 05, 2020 at 03:16:04PM +0200, Thomas Gleixner wrote: > From: Andy Lutomirski > > A data breakpoint near the top of an IST stack will cause unresoverable unrecoverable > recursion. A data breakpoint on the GDT, IDT, or TSS is terrifying. "terrifying" huh? Colorful. :) > Prevent either of these from happening. > > Co-developed-by: Peter Zijlstra > Signed-off-by: Andy Lutomirski > Signed-off-by: Peter Zijlstra (Intel) > Signed-off-by: Thomas Gleixner > --- > arch/x86/kernel/hw_breakpoint.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette