From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22460 invoked by alias); 21 May 2003 15:41:43 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 22401 invoked from network); 21 May 2003 15:41:42 -0000 Received: from unknown (HELO crack.them.org) (146.82.138.56) by sources.redhat.com with SMTP; 21 May 2003 15:41:42 -0000 Received: from nevyn.them.org ([66.93.61.169] ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 19IVjG-0008Nz-00; Wed, 21 May 2003 10:42:10 -0500 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 19IVig-00020X-00; Wed, 21 May 2003 11:41:34 -0400 Date: Wed, 21 May 2003 15:41:00 -0000 From: Daniel Jacobowitz To: Andrew Cagney Cc: cgd@broadcom.com, kevinb@redhat.com, gdb-patches@sources.redhat.com Subject: Re: [WIP/RFC] MIPS registers overhaul Message-ID: <20030521154134.GA7667@nevyn.them.org> Mail-Followup-To: Andrew Cagney , cgd@broadcom.com, kevinb@redhat.com, gdb-patches@sources.redhat.com References: <1030516230550.ZM12582@localhost.localdomain> <1030517004052.ZM13153@localhost.localdomain> <3ECA9587.4090407@redhat.com> <3ECB9C8F.1060706@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3ECB9C8F.1060706@redhat.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-05/txt/msg00384.txt.bz2 On Wed, May 21, 2003 at 11:34:39AM -0400, Andrew Cagney wrote: > >At Tue, 20 May 2003 16:52:23 -0400, Andrew Cagney wrote: > > > >>> At Sat, 17 May 2003 00:41:10 +0000 (UTC), "Kevin Buettner" wrote: > >>> > > > >>>> Unfortunately, it isn't reasonable to use an ABI-specific RDA to debug > >>>> an application which uses a different ABI. It might kind of, sort of > >>>> work some of the time, but there are various things that won't work. > >>>> You've just identified one of the problems. > > > >>> > >>> > >>> BTW, because of this kind of problem, does it even make sense that > >>> when talking to a mips64 kernel but using an o32 rda (or gdbserver > >>> 8-), you'd use a "mips64" protocol? I.e., why wouldn't it just use > >>> the 32-bit mips protocol, since from you're debugging a 32-bit binary > >>> with a 32-bit debugging daemon... > > > >> > >>Ignoring the FP registers, I think it does make sense. o32 code does > >>run on a 64 bit ISA. Who is GDB to decide what the ISA should be. > > That came out wrong. > > I think a GDB debugging a remote 64 bit MIPS ISA should always expect 64 > bit GPRs and 64 bit FPRs when the ISA is 64 bits, regardless of the ABI. > > It is quite legitimate, for instance, for GDB to do something as sick-o > as clearing the FR bit and then resume the thread. The register > save/restore code needs to correctly handle this - be it reject the > operation or ``do the right thing''. But when using rda or gdbserver to debug an o32 application, then for all intents and purposes we are debugging a 32-bit ISA. The kernel will not allow us to change the FR bit. The app will never see 64-bit registers. The 32-bit protocol makes more sense here IMO. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer