Re: kgdb support in vanilla 2.6.2

[George Anzinger <george@mvista.com>]

Amit S. Kale wrote:
> On Wednesday 03 Mar 2004 5:22 am, George Anzinger wrote:
> 
>>Andrew Morton wrote:
>>
>>>George Anzinger <george@mvista.com> wrote:
>>>
>>>>Often it is not clear just why we are in the stub, given that
>>>>we trap such things as kernel page faults, NMI watchdog, BUG macros and
>>>>such.
>>>
>>>Yes, that can be confusing.  A little printk on the console prior to
>>>entering the debugger would be nice.
>>
>>That assumes that one can do a printk and not run into a lock.  Far better
>>IMNSHO is to provide a simple way to get it from gdb.  One can then even
>>provide a gdb macro to print the relevant source line and its surrounds.  I
>>my lighter moments I call this the comefrom macro :)  In my kgdb it would
>>look like:
>>
>>l * kgdb_info.called_from
> 
> 
> How about echoing "Waiting for gdb connection" stright into the serial line 
> without any encoding? Since gdb won't be connected to the other end, and many 
> a times a minicom could be running at the other end, it'll give a user an 
> indication of kgdb being ready.

Uh, different solution for a different problem.  The above command to gdb causes 
the source code around the location "kgdb_info.called_from" to be displayed.  In 
the -mm version, this is location is filled in by kgdb with the return address 
for the "kgdb_handle_exception()".  This allows you to see just why you are in kgdb.



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