From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp05.in.ibm.com (e28smtp05.in.ibm.com [122.248.162.5]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp05.in.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 9E223B7DE4 for ; Wed, 12 May 2010 13:34:42 +1000 (EST) Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by e28smtp05.in.ibm.com (8.14.3/8.13.1) with ESMTP id o4C3YcHc011382 for ; Wed, 12 May 2010 09:04:38 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o4C3YbcS3338494 for ; Wed, 12 May 2010 09:04:37 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o4C3YbGL008652 for ; Wed, 12 May 2010 13:34:38 +1000 Date: Wed, 12 May 2010 09:04:34 +0530 From: "K.Prasad" To: Paul Mackerras Subject: Re: [Patch 2/2] PPC64-HWBKPT: Implement hw-breakpoints for PPC64 Message-ID: <20100512033434.GA6319@in.ibm.com> References: <20100414033555.746326035@pr> <20100414034827.GC6571@in.ibm.com> <20100503062330.GB19365@drongo> <20100504203302.GA3894@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20100504203302.GA3894@in.ibm.com> Cc: Michael Neuling , Benjamin Herrenschmidt , shaggy@linux.vnet.ibm.com, Frederic Weisbecker , David Gibson , "linuxppc-dev@ozlabs.org" , Alan Stern , Roland McGrath Reply-To: prasad@linux.vnet.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, May 05, 2010 at 02:03:03AM +0530, K.Prasad wrote: > On Mon, May 03, 2010 at 04:23:30PM +1000, Paul Mackerras wrote: > > On Wed, Apr 14, 2010 at 09:18:27AM +0530, K.Prasad wrote: > > [snipped] > > It has been pointed out to me before (Roland's mail Ref:linuxppc-dev > message-id: 20100119100335.3EB621DE@magilla.sf.frob.com) that there will > be too many corner cases that will be difficult to foresee, however your > above list appears to be exhaustive. While the alternatives to this being > a fallback to one-shot breakpoints (thereby leading to confusing > hw-breakpoint interface semantics), this is an attempt to generate > continuous and 'trigger-after-execute' (for non-ptrace requests) > breakpoint exceptions. I believe that, with the addressal of concerns > cited above, the resultant patchset would be one that achieves the > stated design goals with no loss to existing functionality. > Hi Paul, > I intend to send out another version of this patchset with fixes as > described in my replies above (unless I hear objections to it :-)). > Meanwhile, a little sickness had kept me away from working on this patchset. I have now posted a new version of the same here () which contains changes as described above. A few more changes to the patch is impending post merger of Frederic's patches (which are now in -tip) into mainline (ref: commit 73266fc1df2f94cf72b3beba3eee3b88ed0b0664 to 777d0411cd1e384115985dac5ccd42031e3eee2b); mainly due to the new ability for a per-task breakpoint to request kernel-space breakpoints (the notion of kernel- vs user-bp would also become obsolete, it is better to call them per-cpu vs per-task breakpoints). Also, I find that possibility of a kernel-thread specific breakpoint (which can migrate across CPUs) has not been thought and implemented well in this patch (will be much easier after merger of Frederic's patch). I would prefer to have atleast some version of the patch included in mainline before bringing in support for the same. Thanks, K.Prasad