Re: kgdb on EM64T

[George Anzinger <george@mvista.com>]

Wilkerson, Bryan P wrote:
> Thanks you Tom and George for the tips on using kgdb with
> 2.6.13-rc4-mm1.  
> 
> I almost have it working but kgdb seems to have a few issues.  I can get
> it running from the dev machine using the kgdb and console=kgdb boot
> options on the test kernel.  The kernel waits as it should and when I
> attach with "target remote /dev/ttyS0" and I can continue the boot but
> eventually it gets to a point in the boot where it frees unused kernel
> memory successfully and then a warning, "unable to open an initial
> console",  followed by, "Kernel panic - not syncing: Attempted to kill
> init!"
> 
> Removing the console=kgdb boot option and the machine boots all the way
> to run level 5.   I tried to break into kgdb at this point using the 
> 	$echo -e "\003" > /dev/ttyS0
> from the dev machine but the test kernel panics at gdb_interrupt+75 when
> it receives anything on the serial port.  Hmmm...
> 
> I'm wondering if I'm maybe just the first to try this on EM64T (kernel
> builds in the arch/x86_64 tree).   

Possibly:).  Since the serial port seems to work (i.e. the first test 
above), the fault seems to be in handling the int3.  Is int3 the right 
instruction for this machine?  If not you would make the change in 
kgdb.h.  I think that is the only place it is defined.
> 
-- 
George Anzinger   george@mvista.com
HRT (High-res-timers):  http://sourceforge.net/projects/high-res-timers/