From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp07.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 10ECE10088E for ; Mon, 16 Jan 2012 22:52:32 +1100 (EST) Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 16 Jan 2012 11:48:40 +1000 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q0GBqNfe5251106 for ; Mon, 16 Jan 2012 22:52:23 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q0GBqMVX007951 for ; Mon, 16 Jan 2012 22:52:23 +1100 Date: Mon, 16 Jan 2012 19:18:33 +1100 From: David Gibson To: "K.Prasad" Subject: Re: [PATCH 2/2] [PowerPC Book3E] Introduce new ptrace debug feature flag Message-ID: <20120116081833.GG4512@truffala.fritz.box> References: <20111208111212.GB3720@in.ibm.com> <20111208112330.GB24484@in.ibm.com> <20111221005502.GE5188@truffala.fritz.box> <20111222093447.GD26407@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20111222093447.GD26407@in.ibm.com> Cc: linuxppc-dev@ozlabs.org, Thiago Jung Bauermann , Edjunior Barbosa Machado List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Dec 22, 2011 at 03:04:47PM +0530, K.Prasad wrote: > On Wed, Dec 21, 2011 at 11:55:02AM +1100, David Gibson wrote: > > On Thu, Dec 08, 2011 at 04:53:30PM +0530, K.Prasad wrote: > > > While PPC_PTRACE_SETHWDEBUG ptrace flag in PowerPC accepts > > > PPC_BREAKPOINT_MODE_EXACT mode of breakpoint, the same is not intimated to the > > > user-space debuggers (like GDB) who may want to use it. Hence we introduce a > > > new PPC_DEBUG_FEATURE_DATA_BP_EXACT flag which will be populated on the > > > "features" member of "struct ppc_debug_info" to advertise support for the > > > same on Book3E PowerPC processors. > > > > Hrm. I had assumed the reason there wasn't a feature bit for EXACT > > originally was that EXACT breakpoints were *always* supposed to be > > supported by the new interface. > > > > Okay. Although BookS doesn't support EXACT breakpoints, it is possible > (after the introduction of new hw-breakpoint interfaces) to request for > a breakpoint of length 1 Byte. Hrm. An EXACT breakpoint is not exactly the same as a range breakpoint of length 1 (consider unaligned accesses). But despite that, it should be possible to implement exact breakpoints on Book3S server hardware with some software filtering. And since that leaves no hardware that *can't* implement exact breakpoints (directly or indirectly), I'm not yet convinced of the need for a flag bit. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson