RISC-V: Is it reasonable to extend current target_description for KGDB?

[Vincent Chen]

On Wed, Oct 16, 2019 at 9:21 PM Maciej W. Rozycki <macro@wdc.com> wrote:
>
> On Tue, 15 Oct 2019, Jim Wilson wrote:
>
> > One possible solution is to add a RISC-V specific command to choose
> > the register set used for the default p packet.  That way, if there
> > are problems with adding registers to it, people have the option to
> > switch back to the old way.  We already have the "set riscv
> > use-compressed-breakpoints [auto|on|off]" command.  So we could add a
> > similar command to choose the number of registers in the default p
> > packet, try changing the default to the full 36 register set, and wait
> > to see who complains.  People that complain can be told about the
> > command to switch back to the old 32 (33?) register set.
>
>  There's such a generic command already available:
>
> (gdb) set tdesc filename ...
>
>  NB, this has nothing to do with the use of `g'/`G' vs `p'/`P' packets,
> both use the same register indices; for the overlapping part, that is of
> course.  Then no heuristics can cover registers outside the range of the
> `g'/`G' packets of course, an XML description does have to be provided for
> those registers to be recognised.
>

I understood. From the perspective of flexibility, compatibility and
user-friendly, I agree that adding the negotiation support to the
kernel is a better way.

Thanks to Jim, Pedro, and Macie for your comments.

Best regards,
Vincent Chen