[PATCH] Add support for Xtensa

[Chris Zankel]

Hi Denys,

On 03/26/2013 04:25 AM, Denys Vlasenko wrote:
> On 03/25/2013 06:29 PM, Chris Zankel wrote:
>> I checked again, but couldn't find a good way to use the regset
>> directly. As a recap, Xtensa is a configurable processor with a
>> variable number of internal registers, and from the register set, it
>> is not always clear where the syscall arguments are without knowing
>> the configuration dependent register count. Goal is to fix it with
>> getregset, which is currently not supported, so we can eventually
>> deprecate the upeek method. 
> Is there a plan to implement PTRACE_GETREGSET (in kernel)
> for this arch?

It's definitely on the plan, but not necessarily highest priority right
now. It's not so much a problem for the base registers (which strace
needs), but the complication for Xtensa is its configurable
architecture, which allows to define any number of custom registers. The
current implementation to get those registers (getxregs, setxregs)
requires the client (gdb, etc.) to know the exact processor
configuration and register layout. Ideally, that tool would adapt to the
configuration at run-time instead of compile time, and regsets might be
just the right vehicle for such implementation.

Thanks,
-Chris