kernel debugging in MontaVista Journeyman 2.0

kernel debugging in MontaVista Journeyman 2.0

[Viktor Lapinskii]

Hello!

We have Motorola Sandpoint with PPMC8240 and MontaVista Journeyman 2.0.
Budget constraints do not allow us to have a full version of MontaVista
Linux and I am trying to find some ways to do kernel debugging with the
Journeyman version of linux-2.4.2_hhl20.

We need to perform some measurements on a network card driver.  Ideally,
it would be great to obtain executuion traces (on the machine instruction
level) of different components of that driver (eventaully with timestamps)
and also (probably indirectly) measure DMA exchanges between the network
card and RAM.  Setting breakpoints is also desirable.

Journeyman apparently does not have KGDB support and I would highly
appreciate your advice on how such measurements / trace construction can
be done (besides using occiloscope or printouts and pencil).  It's the
first time I am trying to get deep into the kernel so any of your
suggestions/references would be very helpful.

Thank you,

Viktor


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Re: kernel debugging in MontaVista Journeyman 2.0

[Wolfgang Denk]

Dear Viktor,

in message <Pine.A41.4.44.0202071800550.13790-100000@pacific.ece.utexas.edu> you wrote:
>
>
> We have Motorola Sandpoint with PPMC8240 and MontaVista Journeyman 2.0.
> Budget constraints do not allow us to have a full version of MontaVista
> Linux and I am trying to find some ways to do kernel debugging with the
> Journeyman version of linux-2.4.2_hhl20.

IMHO it does not matter much  if  you're  running  MV  Journeyman  or
professional or _any_ other version of the Linux kernel.

The most efficient way (IMHO) for kernel debugging is  using  a  JTAG
debugger  like  the  Abatron  BDI2000.  Note  that  I'm talking about
debugging here...

> We need to perform some measurements on a network card driver.  Ideally,
> it would be great to obtain executuion traces (on the machine instruction

Performance analysis and execution traces is a different story.

> level) of different components of that driver (eventaully with timestamps)
> and also (probably indirectly) measure DMA exchanges between the network
> card and RAM.  Setting breakpoints is also desirable.

You have several  options  for  traces  /  timing  analysis.  A  pure
software  approach  is  the  Linux  Trace  Toolkit, which can provide
extremely interesting information, and it's _free_.

A mixed approach (software instrumentation and hardware  support  for
data  accquisition)  is  CodeTEST  by  Applied Microsystems; it's not
exactly cheap but can be used for a lot in interesting things, up  to
and  including  MC/DC code coverage; execution traces with timestamps
are included, too.

There are probably a couple of other tools that allow oa  combination
of  debugging  and  tracing.  You  may  want  to check out tools like
Lauterbach's TRACE32 for instance - but be careful to ask  for  Linux
MMU  support;  I  know that they have it for MPC8xx CPUs, but I'm not
sure about the 82xx.

> Journeyman apparently does not have KGDB support and I would highly

You don't need kgdb when you have a BDM / JTAG debugger :-)

> be done (besides using occiloscope or printouts and pencil).  It's the
> first time I am trying to get deep into the kernel so any of your
> suggestions/references would be very helpful.

My recommendation is to start with LTT; probably  this  provides  all
information you need, and maybe more.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Perfection is reached, not when there is no longer anything  to  add,
but when there is no longer anything to take away.
- Antoine de Saint-Exupery

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