From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16885 invoked by alias); 10 Jul 2008 11:07:56 -0000 Received: (qmail 16875 invoked by uid 22791); 10 Jul 2008 11:07:55 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 10 Jul 2008 11:07:33 +0000 Received: (qmail 685 invoked from network); 10 Jul 2008 11:07:31 -0000 Received: from unknown (HELO orlando.local) (pedro@127.0.0.2) by mail.codesourcery.com with ESMTPA; 10 Jul 2008 11:07:31 -0000 From: Pedro Alves To: Michael Snyder Subject: Re: [RFA] set/show enable-software-singlestep Date: Thu, 10 Jul 2008 11:07:00 -0000 User-Agent: KMail/1.9.9 Cc: Daniel Jacobowitz , gdb-patches@sourceware.org, Joel Brobecker References: <1214331534.3601.1211.camel@localhost.localdomain> <1214862215.3601.1525.camel@localhost.localdomain> <1215657970.3549.157.camel@localhost.localdomain> In-Reply-To: <1215657970.3549.157.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200807101207.19744.pedro@codesourcery.com> X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2008-07/txt/msg00148.txt.bz2 Hi Michael, Sorry for the silence, On Thursday 10 July 2008 03:46:10, Michael Snyder wrote: > Silence equals assent? I had understood the consensus was that the command would be useful for now. It would be really nice if someone that had a target that always required disabling software-singlestepping stepped forward to add the GDB/remote smarts to do it automatically, though. ;-) > > On Mon, 2008-06-30 at 14:43 -0700, Michael Snyder wrote: > > Any convergence on this? > > > > On Wed, 2008-06-25 at 16:03 +0100, Pedro Alves wrote: > > > A Wednesday 25 June 2008 15:42:15, Daniel Jacobowitz escreveu: > > > > On Wed, Jun 25, 2008 at 03:14:38PM +0100, Pedro Alves wrote: > > > > > A Wednesday 25 June 2008 14:34:57, Daniel Jacobowitz wrote: > > > > > > I think it should already be auto. can-use-software-singlestep > > > > > > is unintuitive - either do use it, don't use it, or use GDB's > > > > > > best judgement. And if the user selects to use it and it isn't > > > > > > supported, that's an error when we next want to singlestep. > > > > > > WDYT? > > > > > > > > > > Well, not really auto. If a ARM stub does software singlestepping > > > > > itself (say we add it to gdbserver), gdb will still do software > > > > > single-stepping (breakpoint dance), wont it? > > > > > > > > What Joel said elsewhere in the thread just now. If we get a stub > > > > that reports definitively that it can single step, that should take > > > > priority over GDB knowing that software singlestep is implemented for > > > > this architecture. > > > > > > What I said elsewhere in the thread just now. :-) The stub should > > > report it, and a new target method is required, that takes precedence > > > for stepping operations. > > > > > > > Um, uh-oh. This will break the overloading of software single step > > > > for bypassing atomic operations. Clearly more thought is required! > > > > > > The stub should just either step it all atomically, and GDB sees > > > only one SIGTRAP, or we force continuing over the sequence with a > > > single-step breakpoint (as we do today), not telling the > > > stub to step at all (as we don't do today...). We seems we need > > > to distinguish this in the reporting mechanism. Another issue is > > > that the atomic operations bypassing is implemented inside > > > the software_singlestepping gdbarch methods. It should be > > > factored out. > > > > > > > Another unfortunate note: we can't trust the vCont reply for this > > > > even though it's clearly the right thing :-( Since current versions > > > > of GDB reject replies without s/S. > > > > > > Yep, I noticed that. We'll need something else, probably > > > qSupported (if we're thinking of supporting multi arch > > > stubs, care must be taken here as well). -- Pedro Alves