Re: mpc8xx-2.2.13 kernel hangs during boot.

Alan Mimms wrote:

Brendan,

We use a serial connection to debug our applications with GDB all the time
using stubs that are part of our "OS".  It certainly is possible.  We put the
devices on the end of a 24 port Livingston Portmaster terminal server and then
setup the ports as raw data ports to which we connect with GDB running on our
main build/debug box.  That way the user can debug something in another room or
across the planet very easily through the network.

Cool.  A little overkill never hurt anybody :)
I'll assume one build/debug box connected directly to the target via a serial cable
or ethernet for now.

I debugged my initial port of the linux kernel to our platform using just this
kind of interface.  You have to commandeer the serial hardware away from the
driver - I simply didn't tell the kernel there was a device there and
configured it "manually" from the GDB nub initialization function which I
called early in main.c.  This works fine for KERNEL debugging.

When you say configured manually what exactly do you mean.
Is this in the kernel itself ?
When you say main.c do you mean init/main.c in the linux kernel source tree ?
Has this got anything to do with the kgdb option in the "make config" process ?
Can ethernet be used to debug the kernel or is a serial port the only or best way to
go ?

For application debugging, you probably want to live in user space.  You COULD
use gdbserver, I think, although I have no experience or knowledge of this.

I'm pretty sure gdbserver is the way to go for debugging applications.  A TCP
connection is a nice way to debug this.

Thanks,
Brendan Simon.


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