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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 10F21C433E1 for ; Mon, 24 Aug 2020 12:00:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E33D12078A for ; Mon, 24 Aug 2020 12:00:56 +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="U8M11KIS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726870AbgHXMAz (ORCPT ); Mon, 24 Aug 2020 08:00:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726306AbgHXMAp (ORCPT ); Mon, 24 Aug 2020 08:00:45 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41151C061573 for ; Mon, 24 Aug 2020 05:00:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=JYP2GCXEu7go+Gvp89pNHC5SHYvaw/EwCONCZQ27CAk=; b=U8M11KISvweMSdTXSMge6KmvUH MBfyzSiMpsGJpXuhXjdG3c4hJNfuHkL3PdJ0QN4FvNPY/imLU/Om4zd2rR09EYk9uX7soVyLQHO5q UIRN7nVC206BWMetQSUpVT3rz8PGEvfLpSDy8fp1FBay+W7U9PTW/BXUICFkNqRdbSKFczGNY/tC4 FKUb/sCEiz608akjRXZorYkiiCJxhsQx/D3AufLyZS6eB3oXwdriJojUHvLsVk9oiYsEvEXrcOVHs 688Syg1P6iGTXt30qgsSQM5exRiQFlPgZxUx8LesbZYXUg6tCSVsM4sBxN4J4pgnyLB4Rwxgwg3ZB +ua361cQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAB9B-0005md-HP; Mon, 24 Aug 2020 12:00:21 +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 A15AA3010D2; Mon, 24 Aug 2020 14:00:17 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 827D92B077D12; Mon, 24 Aug 2020 14:00:17 +0200 (CEST) Date: Mon, 24 Aug 2020 14:00:17 +0200 From: peterz@infradead.org To: Andrew Cooper Cc: Andy Lutomirski , X86 ML , LKML , Kyle Huey , Alexandre Chartre , "Robert O'Callahan" , "Paul E. McKenney" , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , "Josh Poimboeuf" , Daniel Thompson Subject: Re: [PATCH v2 5/8] x86/debug: Simplify #DB signal code Message-ID: <20200824120017.GU1362448@hirez.programming.kicks-ass.net> References: <20200821093912.815135402@infradead.org> <20200821102053.034965283@infradead.org> <20200824110501.GT1362448@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 24, 2020 at 12:26:01PM +0100, Andrew Cooper wrote: > > INT1 is a trap, > > instruction breakpoint is a fault > > > > So if you have: > > > > INT1 > > 1: some-instr > > > > and set an X breakpoint on 1, we'll loose the INT1, right? > > You should get two.  First with a dr6 of 0 (ICEBP, RIP pointing at 1:), > and a second with dr6 indicating the X breakpoint (again, RIP pointing > at 1:). > > SDM Vol3 6.9 PRIORITY AMONG SIMULTANEOUS EXCEPTIONS AND INTERRUPTS Ooh, shiny. Clearly I didn't read enough SDM this morning.