gdbserver for embedded targets?

gdbserver for embedded targets?

[Greg McGary]

Most gdbserver targets are full OSes (Linux, *BSD).  I need a remote stub for an embedded multi-core DSP target.  The DSPs are co-processors of an ARM, similar to the pairing of SPUs with PPC.  When debugging, there will always be a full OS (Linux or Windoze) front-end system available.  System topology looks like so:

    Workstation: gdb client
    ... TCP ...
    x86 front-end: gdbserver
    ... serial ...
    ARM co-processor: target control
    ... shared memory, control registers ...
    DSPs

The DSP doesn't handle interrupts, and all control is handled by the ARM, thus the ARM must run the stub.  Traditional stub functionality (remote protocol handling + target processor control) is divided betweenthe front-end systemthe ARM.  The front-end system will run gdbserver, and the target_ops will be populated with functions that send/receive requests over serial using a compact binary protocol.  The ARM will run a simple command loop.  The gdbserver/ARM interactions will be simple commands toread/write memory & registers, and control execution. 

I really don't want to write a remote-protocol server, and would rather leverage the existing gdbserver, since presumably it is maintained and stays current with enhancements to the remote protocol.

Question: is the gdbserver target_ops interface suitable for such a target?  I'm going to proceed under the assumption that it is, and will supplement if I find deficiencies.

Comments?

G

Re: gdbserver for embedded targets?

[Tom Tromey]

>>>>> "Greg" == Greg McGary <greg.mcgary@gmail.com> writes:

Greg> Question: is the gdbserver target_ops interface suitable for such a
Greg> target?  I'm going to proceed under the assumption that it is, and
Greg> will supplement if I find deficiencies.

Greg> Comments?

I don't know gdbserver very well, so I can't comment on that.

There's also RDA, but I don't know if it is still live or not; but it
seems like it was more explicitly targeted to this sort of thing:

    http://sourceware.org/rda/

Tom

Re: gdbserver for embedded targets?

[Jeremy Bennett]

On Tue, 2012-02-07 at 13:45 -0700, Greg McGary wrote:

<snip>

> I really don't want to write a remote-protocol server, and would
> rather leverage the existing gdbserver, since presumably it is
> maintained and stays current with enhancements to the remote protocol.

Hi Greg,

A Remote Serial Protocol Server for a native target isn't a complex
program. Some simple serial comms to get the packets, and then a switch
statement on the text in the packet. You might find it quicker and
easier to write (or adapt) one, rather than modifying gdbserver.

A while ago, I wrote a short application note of implementing Remote
Serial Protocol Servers, which includes example code you can freely use.
You might find this useful:

        http://www.embecosm.com/download/ean4.html

HTH,


Jeremy

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