Re: TLB Miss booting linux kernel on ppc 405

["Ricardo Ayres Severo" <severo.ricardo@gmail.com>]

Executing without single step the exception doesn't occurs. But at
__log_buf I get only trash, even after reseting the processor.
How can I send some characters to uartlite on asm code?

Thanks,

On Feb 13, 2008 4:32 PM, David Baird <dhbaird@gmail.com> wrote:
> On Feb 13, 2008 11:03 AM, Ricardo Ayres Severo <severo.ricardo@gmail.com> wrote:
> > Here are the srr dump:
> >   srr0: c0002218
> >   srr1: 00021030
> >   srr2: 00001154
> >   srr3: 00000000
>
> Okay, SRR0 tells us that you did in fact have an exception at
> 0xc0002218.  And I am willing to bet that is the line you mentioned
> (line 826 of start_here).  You can match this up with your System.map
> or an objdump -d of vmlinux.
>
> Someone who knows more than I do can correct me on this, but I have a
> suspicion.  As soon virtual (translation) mode is entered, I have had
> a hard time using the normal debugging functions (e.g. single
> instruction stepping and reading memory regions).  While in virtual
> mode, it seemed like I had to resort to these techniques:
>
> - Blinking some LEDs
> - Spitting characters out of a uartlite
> - When an exception occurs, the processor switches back into real mode
> and therefore I can set breakpoints on the beginnings of various
> exception handlers and be able to use normal debugging tools again
>
> So, I have another question.  Can you set a breakpoint on 0x1100 (in
> XMD: bps 0x1100 hw), then just let it run (i.e. do not single step!)
> all the way until an exception happens.  When the exception happens,
> can you then paste the SRR0, SRR1, and the ESR (exception syndrome
> register)?
>
> I hope I am not giving you a run-around here....
>
> -David
>
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-- 
Ricardo Ayres Severo <severo.ricardo@gmail.com>