Re: kgdb for mainline kernel: core-lite [patch 1/3]

[George Anzinger]

Amit S. Kale wrote:
> On Monday 08 Mar 2004 3:56 pm, Andrew Morton wrote:
>
> > "Amit S. Kale" <amitkale@xxxxxxxxxxxxx> wrote:
> >
> > > Here are features that are present only in full kgdb:
> > > 1. Thread support  (aka info threads)
> >
> > argh, disaster.  I discussed this with Tom a week or so ago when it looked
> > like this it was being chopped out and I recall being told that the
> > discussion was referring to something else.
> >
> > Ho-hum, sorry.  Can we please put this back in?
>
>
> Err., well this is one of the particularly dirty parts of kgdb. That's why 
> it's been kept away. It takes care of correct thread backtraces in some rare 
> cases.
>
> If you consider it an absolutely must, we can do something so that the dirty 
> part is kept away and info threads almost always works.

Amit,

I think we should just put the info threads in the core.  No attempt to do any 
trace back from kgdb.  Let them all show up in the switch code.  I have a script 
(gdb macro) that will give a rather decent "info threads" display.  Oh, we need 
to add one other responce to kgdb for the process info gdb command.

 * This query allows the target stub to return an arbitrary string
 * (or strings) giving arbitrary information about the target process.
 * This is optional; the target stub isn't required to implement it.
 *
 * Syntax: qfProcessInfo        request first string
 *         qsProcessInfo        request subsequent string
 * reply:  'O'<hex-encoded-string>
 *         'l'                  last reply (empty)
 */
What we want here is the thread name.

Here is the macro set:

set var $low_sched=0

define do_threads
  if (void)$low_sched==(void)0
	set_b
  end
  thread apply all do_th_lines
end

define do_th_lines
  set var $do_th_co=0
  while ($pc > $low_sched) && ($pc < $high_sched)
    up-silent
    set var $do_th_co=$do_th_co+1
  end
  if $do_th_co==0
    info remote-process
    bt
  else
    up-silent
    info remote-process
    down
  end
end

define set_b
  set var $low_sched=scheduling_functions_start_here
  set var $high_sched=scheduling_functions_end_here
end


~

--
George Anzinger   george@xxxxxxxxxx
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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