From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753759AbZCKRbb (ORCPT ); Wed, 11 Mar 2009 13:31:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752209AbZCKRbX (ORCPT ); Wed, 11 Mar 2009 13:31:23 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:58069 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbZCKRbW (ORCPT ); Wed, 11 Mar 2009 13:31:22 -0400 Date: Wed, 11 Mar 2009 18:30:44 +0100 From: Ingo Molnar To: "K.Prasad" Cc: Alan Stern , Andrew Morton , Linux Kernel Mailing List , Roland McGrath Subject: Re: [patch 00/11] Hardware Breakpoint interfaces Message-ID: <20090311173044.GA9720@elte.hu> References: <20090311121007.GC13835@in.ibm.com> <20090311172506.GC9547@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090311172506.GC9547@in.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * K.Prasad wrote: > On Wed, Mar 11, 2009 at 12:34:43PM -0400, Alan Stern wrote: > > On Wed, 11 Mar 2009, K.Prasad wrote: > > > > > The hardware breakpoint interfaces haven't been put under any CONFIG_ > > > till now, but I think we should bring them under a new config, say > > > CONFIG_HW_BREAKPOINT. It would help create a dependancy for > > > CONFIG_KSYM_TRACER too. > > > > With these patches, ptrace is dependent on hw-breakpoint. > > You can't disable CONFIG_HW_BREAKPOINT without breaking > > ptrace. > > > > Alan Stern > > > > Agreed. We might have to retain the old code for ptrace and > put the new implementation under #ifdef CONFIG_HW_BREAKPOINT > to get them working. What do you think? With the simple reservation mechanism i suggested i have no problem with having HW_BREAKPOINT enabled [selected] unconditionally on x86. Your ptrace changes are an improvement in terms of code quality so as long as the facility is simple and obvious, it's a step forward. #ifdefs are ugly and hard to maintain - especially in such a rarely used and still critical API as ptrace. Ingo