From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25124 invoked by alias); 1 Oct 2007 09:20:31 -0000 Received: (qmail 25114 invoked by uid 22791); 1 Oct 2007 09:20:30 -0000 X-Spam-Status: No, hits=-2.1 required=5.0 tests=AWL,BAYES_00,DK_POLICY_SIGNSOME,FORGED_RCVD_HELO X-Spam-Check-By: sourceware.org Received: from wildebeest.demon.nl (HELO gnu.wildebeest.org) (83.160.170.119) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 01 Oct 2007 09:20:29 +0000 Received: from dijkstra.wildebeest.org ([192.168.1.29]) by gnu.wildebeest.org with esmtp (Exim 4.63) (envelope-from ) id 1IcHRy-0005KT-Ge; Mon, 01 Oct 2007 11:20:27 +0200 Subject: Re: Optimizing watchpoints From: Mark Wielaard To: Phil Muldoon Cc: Roland McGrath , Frysk Hackers In-Reply-To: <4700B9C2.8030005@redhat.com> References: <46FD7036.2010500@redhat.com> <20071001012529.D264A4D0325@magilla.localdomain> <1191228112.3842.24.camel@dijkstra.wildebeest.org> <4700B9C2.8030005@redhat.com> Content-Type: text/plain Date: Mon, 01 Oct 2007 09:20:00 -0000 Message-Id: <1191230426.3842.34.camel@dijkstra.wildebeest.org> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-IsSubscribed: yes Mailing-List: contact frysk-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: frysk-owner@sourceware.org X-SW-Source: 2007-q4/txt/msg00004.txt.bz2 Hi Phil, On Mon, 2007-10-01 at 10:11 +0100, Phil Muldoon wrote: > Mark Wielaard wrote: > > Just a FYI. I see (through a quick kernel grep) PTRACE_SET_DEBUGREG is > > only available on powerpc. For x86[_64] frysk pokes at the hardware > > debug registers through the USR area and getting/setting them > > "directly". This might have to become a special case of the above. > > > Is this a hardware/OS difference do you know, or just a different > implementation in the Frysk PPC ISA? A quick look at the kernel sources makes me believe that this is a kernel/ptrace difference in how to access debug registers between different architectures. The PPC Isa is Frysk doesn't yet support hardware debug register access. But my guess is that it just means it would use a different bank, while on x86 we just see the debug registers as part of the USR bank. Cheers, Mark