gdbserver version quandry

gdbserver version quandry

[John Williams]

Hi folks,

I have recently completed a port of uClinux to the Xilinx Microblaze 
soft-processor architecture.

http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux.

I am now investigating providing gdbserver support for this architecture.

Xilinx ported gcc 2.95 and gdb 5.0 (20010428-1) to support microblaze - 
as I understand it they have no intention of moving forward to a newer 
version of gdb.

So, I think I'm stuck with porting gdbserver from gdb5.0, right?  I know 
this is ancient history, but I don't think I'm about to undertake the 
job of adding a new arch to gdb 6.0...

Some pertinent facts:

1- Miles Bader, who did the v850 port of uClinux and gdbserver, has a 
nice clean script and patch to morph gdbserver 5.1 to support uClinux.

2 - The standard uClinux distribution supported by Snapgear, has a 
hacked version of gdbserver 4.12.3 to support uClinux, but hard-coded 
for m68k arch support only.

So, the question is:  Would it be cleaner for me to

(a) Back-port gdbserver 5.1 to support the gdb 5.0 interface;
(b) Forward port and Clean up the m68k uClinux gdbserver 4.12.3 to 
support the gdb5.0 and microblaze; or
(c) Start from scratch with gdbserver 5.0 and provide microblaze support 
directly?

I'm thinking (a) or (c), depending on how much changed in the 
gdb<->gdbserver communication protocol between 5.0 and 5.1.   Is there 
any online documentation on this - in particular regarding how it 
changed from 5.0 to 5.1?

Superficially - Miles' scripts and patches don't apply cleanly to 
gdbserver 5.0 - some file/directory structures have changed.

Any advice or pointers would be greatly appreciated.

Thanks,

John

Re: gdbserver version quandry

[Daniel Jacobowitz]

On Thu, Nov 06, 2003 at 10:50:00AM +1000, John Williams wrote:
> Hi folks,
> 
> I have recently completed a port of uClinux to the Xilinx Microblaze 
> soft-processor architecture.
> 
> http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux.
> 
> I am now investigating providing gdbserver support for this architecture.
> 
> Xilinx ported gcc 2.95 and gdb 5.0 (20010428-1) to support microblaze - 
> as I understand it they have no intention of moving forward to a newer 
> version of gdb.
> 
> So, I think I'm stuck with porting gdbserver from gdb5.0, right?  I know 
> this is ancient history, but I don't think I'm about to undertake the 
> job of adding a new arch to gdb 6.0...
> 
> Some pertinent facts:
> 
> 1- Miles Bader, who did the v850 port of uClinux and gdbserver, has a 
> nice clean script and patch to morph gdbserver 5.1 to support uClinux.
> 
> 2 - The standard uClinux distribution supported by Snapgear, has a 
> hacked version of gdbserver 4.12.3 to support uClinux, but hard-coded 
> for m68k arch support only.
> 
> So, the question is:  Would it be cleaner for me to
> 
> (a) Back-port gdbserver 5.1 to support the gdb 5.0 interface;
> (b) Forward port and Clean up the m68k uClinux gdbserver 4.12.3 to 
> support the gdb5.0 and microblaze; or
> (c) Start from scratch with gdbserver 5.0 and provide microblaze support 
> directly?
> 
> I'm thinking (a) or (c), depending on how much changed in the 
> gdb<->gdbserver communication protocol between 5.0 and 5.1.   Is there 
> any online documentation on this - in particular regarding how it 
> changed from 5.0 to 5.1?
> 
> Superficially - Miles' scripts and patches don't apply cleanly to 
> gdbserver 5.0 - some file/directory structures have changed.
> 
> Any advice or pointers would be greatly appreciated.

I can't offer you any useful advice.  I didn't start seriously cleaning
up gdbserver until 5.2.

If your gdb 5.0 port supports remote debugging at all, then probably
easiest is to take the most recent version of gdbserver and work from
that.  Then adapt it to speak to your older client.  Not much should be
required.

Anything else is a dead end.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: gdbserver version quandry

[John Williams]

Daniel Jacobowitz wrote:
> On Thu, Nov 06, 2003 at 10:50:00AM +1000, John Williams wrote:
> 
>>Hi folks,
>>
>>I have recently completed a port of uClinux to the Xilinx Microblaze 
>>soft-processor architecture.
>>
>>http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux.
>>
>>I am now investigating providing gdbserver support for this architecture.
> 
> If your gdb 5.0 port supports remote debugging at all, then probably
> easiest is to take the most recent version of gdbserver and work from
> that.  Then adapt it to speak to your older client.  Not much should be
> required.

Yes - microblaze gdb 5.0 does supoprt remote debugging.  Xilinx never 
intended to support (uC)linux, so they wrote their own gdbserver-type 
program to run on the host, which then communicates with a stub on the 
target via a proprietary serial interface.

So then, the question becomes:  is there any info online about providing 
new arch support for gdb/gdbserver?

Also looking at gdbserver version strings in the Makefiles - I see that 
gdbserver versions don't track gdb versions.  In both the gdb5.0 and 
gdb5.1 distributions, the gdbserver version string is 4.12.3...   ???

Thanks,

John

Re: gdbserver version quandry

[Daniel Jacobowitz]

On Thu, Nov 06, 2003 at 11:10:58AM +1000, John Williams wrote:
> Daniel Jacobowitz wrote:
> >On Thu, Nov 06, 2003 at 10:50:00AM +1000, John Williams wrote:
> >
> >>Hi folks,
> >>
> >>I have recently completed a port of uClinux to the Xilinx Microblaze 
> >>soft-processor architecture.
> >>
> >>http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux.
> >>
> >>I am now investigating providing gdbserver support for this architecture.
> >
> >If your gdb 5.0 port supports remote debugging at all, then probably
> >easiest is to take the most recent version of gdbserver and work from
> >that.  Then adapt it to speak to your older client.  Not much should be
> >required.
> 
> Yes - microblaze gdb 5.0 does supoprt remote debugging.  Xilinx never 
> intended to support (uC)linux, so they wrote their own gdbserver-type 
> program to run on the host, which then communicates with a stub on the 
> target via a proprietary serial interface.
> 
> So then, the question becomes:  is there any info online about providing 
> new arch support for gdb/gdbserver?

About gdb, see the gdbint manual.  About gdbserver, no.

> Also looking at gdbserver version strings in the Makefiles - I see that 
> gdbserver versions don't track gdb versions.  In both the gdb5.0 and 
> gdb5.1 distributions, the gdbserver version string is 4.12.3...   ???

Didn't even know there was a version number.  Gdbserver never displays
it.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: gdbserver version quandry

[John Williams]

Daniel Jacobowitz wrote:
> On Thu, Nov 06, 2003 at 11:10:58AM +1000, John Williams wrote:
> 
>>Daniel Jacobowitz wrote:
>>
>>>On Thu, Nov 06, 2003 at 10:50:00AM +1000, John Williams wrote:
>>>
>>>
>>>>Hi folks,
>>>>
>>>>I have recently completed a port of uClinux to the Xilinx Microblaze 
>>>>soft-processor architecture.
>>>>
>>>>http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux.
>>>>
>>>>I am now investigating providing gdbserver support for this architecture.
>>>
>>>If your gdb 5.0 port supports remote debugging at all, then probably
>>>easiest is to take the most recent version of gdbserver and work from
>>>that.  Then adapt it to speak to your older client.  Not much should be
>>>required.
>>
>>Yes - microblaze gdb 5.0 does supoprt remote debugging.  Xilinx never 
>>intended to support (uC)linux, so they wrote their own gdbserver-type 
>>program to run on the host, which then communicates with a stub on the 
>>target via a proprietary serial interface.
>>
>>So then, the question becomes:  is there any info online about providing 
>>new arch support for gdb/gdbserver?
> 
> 
> About gdb, see the gdbint manual.  About gdbserver, no.

OK thanks.  Looking at versions of gdbserver post gdb5.2, it's cleaned 
up a lot, and I can easily work with what's there.

>>Also looking at gdbserver version strings in the Makefiles - I see that 
>>gdbserver versions don't track gdb versions.  In both the gdb5.0 and 
>>gdb5.1 distributions, the gdbserver version string is 4.12.3...   ???
> 
> Didn't even know there was a version number.  Gdbserver never displays
> it.

It's in the Makefile - not sure if it actually goes anywhere though.

Cheers,

John