Debugging Fiasco OC + L4Re + L4Linux together

Adam Lackorzynski adam at
Tue Jun 9 23:50:32 CEST 2015


On Mon Jun 08, 2015 at 11:51:22 +0200, Mahdi Aichouch wrote:
> I tried to debug Fiasco OC + L4Re + L4Linux
> using a DS-5 IDE and a DSTREAM JTAG on an i.MX 6 device.
> I was able to do a step-by-step through the source code of L4RE until
> I reach the " *virtual* *void* boot_kernel(unsigned long entry) "
> function in support.h (see screenshot 1) which is the function in L4Re that
> enters the Fiasco
> kernel, from there when I execute a "step into" action in order to execute
> the next
> instruction which is in Fiasco kernel the debugger go into "running" mode
> (see screenshot 2).
> I am unable to do a step-by-step walk neither in the Fiasco kernel nor
> in l4linux source code.
> Stopping the debugger after that do only give a disassembly information.
> Is it possible to debug all the Fiasco OC + L4Re + L4Linux together?
> Are there any debugger configurations that I might be missing?

Depends really. My own experience is that using JTAG is useful but only
for low-level issues and not for high-level application debugging.
Others might see this different building on their experience and way of
working. But this probably also requires OS specific adaptions of the
debugger software which is typically not there. Also, loosing the
debugging between CPU state changes sounds familiar to me. So you're
not missing anything regarding this, same experience for me. Debugging
is really mostly looking into this and figuring out what's going wrong.

Adam                 adam at

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