RE: Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1)

[Daniel Walker]

On Wed, 2006-01-04 at 10:28 +0100, kus Kusche Klaus wrote:
> > From: Daniel Walker
> > Ok, yet another patch. This one uses the correct lowlevel calls, and I
> > fixed the call ordering.
> 
> Hmm, I have no deep knowledge of ARM assembler programming,
> but your patch branches to a C subroutine without setting up a
> return address in the lr register.
> 
> Hence, the return in trace_irqs_... jumps to god-knows-where,
> but not back to the next instruction.
> 
> As a wild guess, I replaced the "b trace_irqs_..." with
> "bl trace_irqs_...".

Ok .

> With this change, the kernel boots fine, but the system seems to go
> into an infinite loop as soon as the first usermode processes start.
> Most likely, my change messes up the lr register of some surrounding
> context.

That's odd. Do you have an OOPS, or is it just a silent hang?


Daniel

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