remote gdb, kgdb and ddb
Julian Elischer
julian at elischer.org
Wed Nov 1 18:10:14 UTC 2006
John Baldwin wrote:
> 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
>
cool
I'll try it today.
> I think I used to use that a few years ago.
>
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