Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753801Ab0ATSdE (ORCPT ); Wed, 20 Jan 2010 13:33:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752577Ab0ATSdA (ORCPT ); Wed, 20 Jan 2010 13:33:00 -0500 Received: from one.firstfloor.org ([213.235.205.2]:46874 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752271Ab0ATSdA (ORCPT ); Wed, 20 Jan 2010 13:33:00 -0500 To: Peter Zijlstra Cc: Avi Kivity , ananth@in.ibm.com, Jim Keniston , Srikar Dronamraju , Ingo Molnar , Arnaldo Carvalho de Melo , utrace-devel , Frederic Weisbecker , Masami Hiramatsu , Maneesh Soni , Mark Wielaard , LKML Subject: Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP) From: Andi Kleen References: <20100111122521.22050.3654.sendpatchset@srikar.in.ibm.com> <20100111122529.22050.32596.sendpatchset@srikar.in.ibm.com> <1263467289.4244.288.camel@laptop> <1263498366.4875.25.camel@localhost.localdomain> <1263546228.4244.343.camel@laptop> <20100115093831.GC26396@in.ibm.com> <1263549014.4244.374.camel@laptop> <4B53213C.9050303@redhat.com> <1263739939.557.20938.camel@twins> <4B5325CF.5000001@redhat.com> <1263740593.557.20967.camel@twins> <4B53661A.9090907@redhat.com> <1263800752.4283.19.camel@laptop> <4B543F93.3060509@redhat.com> <1263815072.4283.305.camel@laptop> <4B544D7C.2060708@redhat.com> <1263816396.4283.361.camel@laptop> <4B544F8E.1080603@redhat.com> <1263816857.4283.381.camel@laptop> Date: Wed, 20 Jan 2010 19:32:57 +0100 In-Reply-To: <1263816857.4283.381.camel@laptop> (Peter Zijlstra's message of "Mon, 18 Jan 2010 13:14:17 +0100") Message-ID: <87ska039uu.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 651 Lines: 20 Peter Zijlstra writes: > > With CPL2 or RPL on user segments the protection issue seems to be > manageable for running the instructions from kernel space. Nope -- it doesn't work on 64bit and even on 32bit can have large costs on some CPUs. Also designing 32bit only features in 2010 would seem rather .... unfortunate. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/