Export exception cause register to userspace ?

[Dmitry Antipov <antipov@ru.mvista.com>]

Hello,

I'm working on a debugging software which should be able to determine an
exact reason of exception which may (and should) be processed within user
space - SIGTRAP, for example. This information should be extracted from
cause register (CP0 register 13, select 0), which is cp0_cause of pt_regs.
But this register is not stored within sigcontext of signal frame, so
it's value is not available from signal handler. Is it a good idea to add a
dedicated sigcontext field to store cause register ?

Dmitry