Re: [PATCH v2] gdbserver: bfin: new port

Andrew Stubbs
2010-12-14T09:37:45Z

On 13/12/10 18:43, Pedro Alves wrote:
> Hmmm. These last 6 look to be some kind of pseudo registers, not
> part of the ISA -- I'm quite surprised to see these here, as
> part of the bfin core register set. I understand these to be
> fdpic related; ISTR some discussion about making these be reported
> with a new qXfer object? That'd be better, IMO.

Right, the SH-2A FDPIC implementation uses qXfer to deal with the FDPIC
settings. The SG++ gdb has a (more-or-less) target independent mechanism
for retrieving the load maps. This has not been submitted upstream
simply because it's not complete. The SH-2A FDPIC kernel does (did) not
support breakpoints, and single stepping is (was) rather broken, so I
never got further than being able to relocate the main program.

For SH-2A, at least, the kernel does not expose the load maps as
registers, but has extra ptrace queries PTRACE_GETFDPIC_EXEC and
PTRACE_GETFDPIC_INTERP.

The gdbserver reads these via qXfer:fdpic:read:exec and
qXfer:fdpic:read:interp.

Hope that helps

Andrew