From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932888AbbERU61 (ORCPT ); Mon, 18 May 2015 16:58:27 -0400 Received: from www.linutronix.de ([62.245.132.108]:51171 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932505AbbERU6Z (ORCPT ); Mon, 18 May 2015 16:58:25 -0400 Date: Mon, 18 May 2015 22:58:34 +0200 (CEST) From: Thomas Gleixner To: Dave Hansen cc: linux-kernel@vger.kernel.org, x86@kernel.org, dave.hansen@linux.intel.com Subject: Re: [PATCH 09/19] x86, mpx: trace entry to bounds exception paths In-Reply-To: <20150508185952.3D3B9085@viggo.jf.intel.com> Message-ID: References: <20150508185948.4C19F4B0@viggo.jf.intel.com> <20150508185952.3D3B9085@viggo.jf.intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 May 2015, Dave Hansen wrote: > This patch adds a trace point for the case where we are > passing the exception up to userspace with a signal. > > We are also explicit that we're printing out the inverse of > the 'upper' that we encounter. If you want to filter, for > instance, you need to ~ the value first. Confused. What is the point of printing the complement of upper? Lets assume that my boundaries are: lower = 0x10000 upper = 0x1ffff So the trace will tell me: pointer: 0x40000 lower: 0x10000 ~upper: 0xfffffffffff70000 Even if the upper bound is not inclusive (and I can't be bothered to look it up right now), i.e. in the example above upper = 0x20000 we would get pointer: 0x40000 lower: 0x10000 ~upper: 0xfffffffffffdffff I have a hard time to understand the value of this over: pointer: 0x40000 lower: 0x10000 upper: 0x20000 Thanks, tglx