From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 18 Dec 2001 09:27:10 -0500 From: Kent Borg To: linuxppc-embedded@lists.linuxppc.org Cc: marc.paquin@motorola.com, peter.barada@motorola.com Subject: Re: Good GDB Version? Message-ID: <20011218092710.A4505@borg.org> References: <20011214135312.B12904@borg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20011214135312.B12904@borg.org>; from kentborg@borg.org on Fri, Dec 14, 2001 at 01:53:12PM -0500 Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: On Fri, Dec 14, 2001 at 01:53:12PM -0500, I wrote: > We are having problems with gdb. And, though we have not gotten to the bottom of it, we seem to have a hardware problem. But a bizarre one. We download our code, watch the kernel boot, get an sh prompt. Fire up ethernet, do an NFS mount of a directory on the development machine. Launch gdbserver on a trivial helloworld program, attach from gdb on the development machine (using ethernet). All that works. It would seem to suggest the hardware is working, right? Well, that's what we thought. Tell gdb to continue. Immediately get a SIGTRAP. And further attempts to use gdb act strange, such as after hitting a breakpoint not being able to continue from there. Re-downloading the boot ROM does not fix it. Swap in a different logic card, do all the above, and everything is the same except that initial SIGTRAP doesn't happen and breakpoints can be continued from and everything seems completely happy. That board works. Swap in the physical boot ROM from the good board to the bad board and the problem stays with the bad board. Both boards have the same rev of the 405GP. How could we have crafted a custom board that can recognize that gdb is running an only malfunction then? I didn't know hardware could be so clever. My only guess is something hanging around the JTAG (or is it BDM?) debug port might be funny--for the debug port has privileged access to some of the same internal hardware that gdb uses. Maybe a hardware fault there could cause spurious SIGTRAPs--or maybe something is fritzed inside the 405's debug hardware. Strange. -kb ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/