remote gdb, kgdb and ddb
John Baldwin
jhb at freebsd.org
Wed Nov 1 16:45:24 UTC 2006
On Tuesday 31 October 2006 20:13, Julian Elischer wrote:
> it's been a bew years since I did this..
>
> some questions..
>
> why kgdb instead of gdb -k ?
>
> for remote, gdb seems to work fine
> kgdb -r /dev/cuad0 kernel.debug thinks it's working but seems to get
> confused a lot..
No idea, ask marcel perhaps. I only use kgdb on coredumps.
> gdb with the following .gdbinit file seems to work as well.
> file kernel.debug
> set verbose 1
> set remotebreak 1
> set remotebaud 9600
> set remotedevice /dev/cuad0
> target remote /dev/cuad0
>
> though I'm not convinced I'm seeing the last frame in which the
> trap occurs. (ddb shows one more frame).
This is one of the things kgdb fixes (it has frame sniffers for trapframes).
> Now that I have my machine in remote gdb, the documentation
> (as sparse as it is) doesnt't say how to make the machine reboot.
>
> from ddb I can do 'call cpu_reset' which seems to work, but
> I haven't succedded in making gdb do anything similar,
> nor to drop back into ddb. At one stage 'detach' used to do that
> but it seems to have stopped working.
Try the following from src/tools/debugscripts/gdbinit.kernel:
# Switch back to ddb
define ddb
set boothowto=0x80000000
s
end
document ddb
Switch back to ddb.
end
I think I used to use that a few years ago.
--
John Baldwin
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