I use the FS2 probe with sde-gdb on a nearly daily basis.
Are you compiling your kernel with -g -O1 ?
You can also try 'hbreak' instead of 'break' in sde-gdb.
On Wed, 2008-08-13 at 09:05 +0200, Brian Foster wrote:
> On Tuesday 12 August 2008 18:27:42 Maciej W. Rozycki wrote:
> > On Tue, 12 Aug 2008, Brian Foster wrote:
> > > I'm using the commercial FS² (First Silicon Systems, now owned
> > > by MIPS) EJTAG probe. [ ... ] There is no ‘gdbserver’ in this
> > > setup per se, albeit I suppose the protocol between ‘gdb’ and
> > > the FS² software [ ... ] might be similar/identical[?]
> > Not really -- it uses a C API called MDI -- the spec is available from
> > MIPS Technologies. I am happy to read somebody finds it useful. :)
> > Debugging the Linux kernel with GDB and this piece of hardware is
> > certainly a lot of fun.
> Thanks for the clarification. I didn't know if MDI
> was related to the remote-‘gdbserver’ stuff or not.
> Re the FS²: When it works, my (somewhat limited)
> experience to-date is it works Ok. And the use of
> TCL on the Host workstation side allows some neat
> tricks. However, at least one thing doesn't work
> reliably for me, albeit I've never investigated:
> Breakpoints in the Linux kernel. They do detonate.
> Then, sometimes, I can ‘c’(ontinue) or ‘s’(tep) Ok.
> But other times, when I ‘c’ or ‘s’, the breakpoint
> detonates again and I'm stuck. I cannot proceed.
> (The same breakpoint might even work once or twice
> and then fail.) Any ideas? AFAICR, this can also
> happen if I try to use the ‘sysnav’ console instead
> of ‘gdb’.
> I understand my predecessor in my job I gave up on
> the FS² (very possibly because of this breakpoint
> issue?) and used a competing (E?)JTAG probe.
> Weirdly, I've only seen this effect with the Linux
> kernel — other kernel-mode software (e.g., the trivial
> custom bootloader) — doesn't seem to suffer from these
> “flakey FS² breakpoints”?