On Tue, Oct 7, 2008 at 10:53 AM, alan yang wrote:
> Could people shed some light how to get remote debugging going, must
> be something that i overlooked, really appreciate.
>


Do you have the right flags for sio or uart in /boot/device.hints? I
have this (for a recent HEAD)::
hint.uart.0.flags="0x90"

You are probably using sio as it is a FreeBSD7 system. From the man
page of sio (the part that talks about flags)::
....
0x00080 use this port for remote kernel debugging
....

Make sure you have this bit set.

Regards,
Navdeep


> Two FreeBSD7 systems, target and development, connected with null
> modem cable on each's COM1.
>
> step 1)
> - rebuild kernel with following options:
> options DDB
> options KDB
> options GDB
>
> makeoptions DEBUG=-g
>
> step 2)
> - from development system
> cd to /usr/src/sys/i386/comiple/MYKERNEL
> kgdb -r /dev/cuad0 kernel.debug
>
> it displays the following:
> Switching to remote protocol
> Ignoring packet error, continuing
> .........
> Couldn't establish connection to remote target
> Malformed response to offset query, timeout
>
> step 3)
> - from targetsystem:
> 1. Ctrl + Alt + Esc to go into db
> 2. from db> type gdb
> 3. it displays: "The remote GDB backend could not be selected"
>
>
>
> On Mon, Oct 6, 2008 at 5:12 PM, alan yang wrote:
>> the problem is, when entering gdb from db as described in the following:
>> --
>> Enter ing gdb from ddb
>> In FreeBSD you can build a kernel with support for both ddb and gdb.
>> You can then
>> change backwards and forwards between them. For example, if you're in
>> ddb, you can
>> go to gdb like this:
>> db> gdb
>> Next trap will enter GDB remote protocol mode
>> db> si step a single instruction to reenter ddb
>> --
>> after typing gdb command, it says: "The remote GDB backend could not
>> be selected"
>> that i am not sure what this indicates; looking at subr_kdb.c, wonder
>> maybe kdb_dbbe_set is not set? seems kdb_dbbe_set is not referenced
>> anywhere, not sure how to get it right.
>>
>> thanks for shed some light ...
>>
>> On Mon, Oct 6, 2008 at 4:26 PM, Pietro Cerutti wrote:
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA512
>>>
>>> alan yang wrote:
>>> | hi, there,
>>> |
>>> | wonder people can shed some lights on remote debugging. i have
>>> | freebsd7 configured with option DDB / KDB / GDB but after entering the
>>> | db on the target system the command gdb gives "the remote GDB backend
>>> | could not be selected".
>>> |
>>> | i browsed through the mailing list, and do find 1 similar post but
>>> | without answer.
>>> |
>>> | thanks in advance & apology if i overlooked things ...
>>>
>>> I suggest the following tutorial:
>>> http://www.lemis.com/grog/Papers/Deb...l/tutorial.pdf
>>>
>>> Have fun
>>>
>>> |
>>> | cheers,
>>> | alan
>>> | _______________________________________________
>>> | freebsd-hackers@freebsd.org mailing list
>>> | http://lists.freebsd.org/mailman/lis...reebsd-hackers
>>> | To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
>>>
>>>
>>> - --
>>> Pietro Cerutti
>>> gahr@FreeBSD.org
>>>
>>> PGP Public Key:
>>> http://gahr.ch/pgp
>>>
>>> -----BEGIN PGP SIGNATURE-----
>>> Version: GnuPG v2.0.9 (FreeBSD)
>>>
>>> iEYEAREKAAYFAkjqnpQACgkQwMJqmJVx945RSwCgoDb0JTr8LS FDB1vpAbGUjb76
>>> ZH0An19HpFVJJTUB5/XnyZc0pIDzgxc3
>>> =6Pdm
>>> -----END PGP SIGNATURE-----
>>>

>>

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