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Re: [RFA 5/8] New port: TI C6x: gdb port
On Thu, 4 Aug 2011, Pedro Alves wrote:
> > Won't GDB need a list of how the register names correspond to DWARF
> > register numbers (which are allocated for all these registers) somewhere?
> AFAICS, gdbserver only exposes A0-A15, CSR, PC, A16-A31
> B16-B31, TSR, ILC, RILC, so I assumed all other registers would be
> system dependent non general purpose control registers, but it's
> probably then that they are only not "user space" registers, and will
> be acessible by bare metal probes/stubs? Linux programs won't access
> those, right? I now browsed the ABI's dwarf section and I got that
I expect most of them are bare metal only - and I don't suppose they are
particularly likely to appear in debug info either, but GDB may as well
know the numbers since they are assigned.
Some of the others *can* however be read/written from userspace (the
documentation of the MVC instruction gives details, for the documented
control registers). (The default in the ABI is for control registers to
Looking at the list of control registers, I'd think that at least AMR,
GFPGFR, GPLYA, GPLYB, FADCR, FAUCR, FMCR, SSR are plausibly relevant to
userspace - userspace code using inline assembly or intrinsics, anyway -
and ought to be available from gdbserver (which might of course require
kernel changes to expose them to ptrace).
Joseph S. Myers