From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp05.au.ibm.com", Issuer "GeoTrust SSL CA" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 58744B70BD for ; Mon, 19 Sep 2011 12:46:03 +1000 (EST) Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp05.au.ibm.com (8.14.4/8.13.1) with ESMTP id p8J2dGmg023729 for ; Mon, 19 Sep 2011 12:39:16 +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 p8J2k2Wc974888 for ; Mon, 19 Sep 2011 12:46:02 +1000 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 p8J2k1cT031296 for ; Mon, 19 Sep 2011 12:46:02 +1000 Date: Mon, 19 Sep 2011 11:10:51 +1000 From: David Gibson To: Thiago Jung Bauermann Subject: Re: [PATCH 2/2] [PowerPC Book3E] Introduce new ptrace debug feature flag Message-ID: <20110919011051.GI9025@yookeroo.fritz.box> References: <20110819074527.GA21817@in.ibm.com> <20110819075338.GC21817@in.ibm.com> <20110823050931.GT30097@yookeroo.fritz.box> <20110823092756.GB2962@in.ibm.com> <20110824040010.GC30097@yookeroo.fritz.box> <1314232903.14168.4.camel@hactar> <20110826044123.GI2308@yookeroo.fritz.box> <1314750461.20347.1.camel@hactar> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1314750461.20347.1.camel@hactar> Cc: linuxppc-dev@ozlabs.org, "K.Prasad" , Edjunior Barbosa Machado List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Aug 30, 2011 at 09:27:41PM -0300, Thiago Jung Bauermann wrote: > On Fri, 2011-08-26 at 14:41 +1000, David Gibson wrote: > > On Wed, Aug 24, 2011 at 09:41:43PM -0300, Thiago Jung Bauermann wrote: > > > On Wed, 2011-08-24 at 14:00 +1000, David Gibson wrote: > > > > On Tue, Aug 23, 2011 at 02:57:56PM +0530, K.Prasad wrote: > > > > > On Tue, Aug 23, 2011 at 03:09:31PM +1000, David Gibson wrote: > > > > > > On Fri, Aug 19, 2011 at 01:23:38PM +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. > > > > > > > > > > > > I thought the idea was that the BP_EXACT mode was the default - if the > > > > > > new interface was supported at all, then BP_EXACT was always > > > > > > supported. So, why do you need a new flag? > > > > > > > > > > > > > > > > Yes, BP_EXACT was always supported but not advertised through > > > > > PPC_PTRACE_GETHWDBGINFO. We're now doing that. > > > > > > > > I can see that. But you haven't answered why. > > > > > > BookS doesn't support BP_EXACT, that's why I suggested this flag. > > > > Surely you can support it with exactly the same sort of filtering > > you're using for the 8-byte ranges now? > > Yes, but to detect that the processor doesn't support BP_EXACT in > hardware I'd have to send a ptrace request, and have it rejected. Only > then I'd step back and simulate one with ranges. Considering that it's > easy and backwards compatible to add a new flag to signal that BP_EXACT > is not supported, I don't know why it would be better to go with the > more convoluted process. No, I'm saying why not implement BP_EXACT on server. -- 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