VxWorks Target

VxWorks Target

[Stephen Pape]

Hello all,

Can anyone tell me the state of the VxWorks support in GDB? While
compiling, I see --configure can take a "-vxworks" target, but I can't
find much more information beyond that. Most of what I see is very
old, and doesn't seem to apply. For example, "target vxworks <host>"
does not work ("Undefined target command").

Is there documentation on the VxWorks implementation, or how to use it?

Thanks!

-Stephen

Re: VxWorks Target

[Yao Qi]

On Tue, Oct 18, 2016 at 10:09 PM, Stephen Pape <srpape@gmail.com> wrote:
> Hello all,
>
> Can anyone tell me the state of the VxWorks support in GDB? While
> compiling, I see --configure can take a "-vxworks" target, but I can't
> find much more information beyond that. Most of what I see is very
> old, and doesn't seem to apply. For example, "target vxworks <host>"
> does not work ("Undefined target command").
>
> Is there documentation on the VxWorks implementation, or how to use it?
>

VxWorks support was removed in 2004.

commit e84ecc995d6a5e4e9114d3cea61717b8a573afb6
Author: Andrew Cagney <cagney@redhat.com>
Date:   Sat Nov 13 23:10:02 2004 +0000

    2004-11-13  Andrew Cagney  <cagney@gnu.org>

        * configure.tgt: Delete i[34567]86-*-vxworks*, m68*-netx-*,
        m68*-*-vxworks*, mips*-*-vxworks*, powerpc-*-vxworks*, and
        sparc-*-vxworks*.
        * NEWS: Mention that vxworks was deleted.
.....

-- 
Yao (齐尧)

Re: VxWorks Target

[Stephen Pape]

Wow, so it's ancient history. If that's the case, there is some
leftover VxWork code hanging around. I was even able to compile gdb
with "--target=powerpc-vxworks", and there are a few files with the
name still in the source:

./include/elf/vxworks.h
./bfd/elf-vxworks.c
./bfd/elf-vxworks.h

The configure script has some VxWorks leftovers as well:

  case "${target}" in
    *-*-vxworks*)
      # VxWorks uses the Dinkumware C++ library.
      noconfigdirs="$noconfigdirs target-libstdc++-v3"
      ;;

Thanks for the reply.

-Stephen

Re: VxWorks Target

[Yao Qi]

On Wed, Oct 19, 2016 at 3:36 PM, Stephen Pape <srpape@gmail.com> wrote:
> Wow, so it's ancient history. If that's the case, there is some
> leftover VxWork code hanging around. I was even able to compile gdb
> with "--target=powerpc-vxworks", and there are a few files with the
> name still in the source:
>
> ./include/elf/vxworks.h
> ./bfd/elf-vxworks.c
> ./bfd/elf-vxworks.h
>
> The configure script has some VxWorks leftovers as well:
>
>   case "${target}" in
>     *-*-vxworks*)
>       # VxWorks uses the Dinkumware C++ library.
>       noconfigdirs="$noconfigdirs target-libstdc++-v3"
>       ;;
>

VxWorks support in GDB was removed, but its support in other
components, like linker, are still there.  They are not leftover.

However, configure should be adjusted so that gdb shouldn't
be configured at all if target is *-*-vxworks*.

-- 
Yao (齐尧)

Re: VxWorks Target

[Stephen Pape]

Okay, thanks. That clears things up a little. I have another question,
if you (or anyone else) can help.

Is there any concept of a "bare" target? For example, just a "powerpc"
target that isn't OS specific. The targets I've seen seem like they're
OS specific ("-linux").

I was thinking of writing a stub that speaks the GDB serial protocol.
I can implement the "add breakpoint", "remove breakpoint", "read
memory", "write memory" type functionality myself, but I'm trying to
figure out how that would work with GDB. Sorry if this doesn't make
sense, I'm just beginning to learn about GDB internals.

Thanks again,

-Stephen

On Wed, Oct 19, 2016 at 11:45 AM, Yao Qi <qiyaoltc@gmail.com> wrote:
> On Wed, Oct 19, 2016 at 3:36 PM, Stephen Pape <srpape@gmail.com> wrote:
>> Wow, so it's ancient history. If that's the case, there is some
>> leftover VxWork code hanging around. I was even able to compile gdb
>> with "--target=powerpc-vxworks", and there are a few files with the
>> name still in the source:
>>
>> ./include/elf/vxworks.h
>> ./bfd/elf-vxworks.c
>> ./bfd/elf-vxworks.h
>>
>> The configure script has some VxWorks leftovers as well:
>>
>>   case "${target}" in
>>     *-*-vxworks*)
>>       # VxWorks uses the Dinkumware C++ library.
>>       noconfigdirs="$noconfigdirs target-libstdc++-v3"
>>       ;;
>>
>
> VxWorks support in GDB was removed, but its support in other
> components, like linker, are still there.  They are not leftover.
>
> However, configure should be adjusted so that gdb shouldn't
> be configured at all if target is *-*-vxworks*.
>
> --
> Yao (齐尧)

Re: VxWorks Target

[Yao Qi]

On Thu, Oct 20, 2016 at 2:08 PM, Stephen Pape <srpape@gmail.com> wrote:
>
> Is there any concept of a "bare" target? For example, just a "powerpc"
> target that isn't OS specific. The targets I've seen seem like they're
> OS specific ("-linux")

There is a "bare metal" target, like powerpc-elf.

>
> I was thinking of writing a stub that speaks the GDB serial protocol.
> I can implement the "add breakpoint", "remove breakpoint", "read
> memory", "write memory" type functionality myself, but I'm trying to
> figure out how that would work with GDB. Sorry if this doesn't make
> sense, I'm just beginning to learn about GDB internals.
>

I don't know much about stubs, but you can take a look at
gdb/stubs/*.c.

-- 
Yao (齐尧)

Re: VxWorks Target

[Joel Brobecker]

Hello,

I just wanted to mention that I posted a patch at some point that
added support for VxWorks 5.x and VxWorks 653 (using the WTX protocol
via the target server to communicate with the target). It was quite
a while ago, and we eventually abandoned the idea of having it in
the GDB repository, but perhaps you can still take advantage of it.

https://www.sourceware.org/ml/gdb-patches/2011-03/msg00251.html

-- 
Joel

Re: VxWorks Target

[Stephen Pape]

Thanks! I was hoping to use WDB to talk directly to the target, but
I'll take a look.

On Fri, Oct 21, 2016 at 11:29 AM, Joel Brobecker <brobecker@adacore.com> wrote:
> Hello,
>
> I just wanted to mention that I posted a patch at some point that
> added support for VxWorks 5.x and VxWorks 653 (using the WTX protocol
> via the target server to communicate with the target). It was quite
> a while ago, and we eventually abandoned the idea of having it in
> the GDB repository, but perhaps you can still take advantage of it.
>
> https://www.sourceware.org/ml/gdb-patches/2011-03/msg00251.html
>
> --
> Joel