Re: [libunwind] Unwinding using the context passed to a signal handler (doesn't work)

[Johan Walles]

David Mosberger wrote:
> unw_getcontext() returns
> the _preserved_ state in ucontext_t, whereas a signal handler saves
> only the _scratch_ state in sigcontext.  To initiate unwinding, the
> preserved state is needed.

Which registers exactly are missing from the sigcontext passed to the signal 
handler?

I was guessing that the only thing needed to walk the stack would be the IP, 
BSP, SP (=R12), and the CFM.  Aren't those part of the signal context?

> You should be able to just do a
> unw_getcontext() anywhere in the signal handler and then step until
> you hit the signal frame (as indicated by unw_is_signal_frame()).

I'd prefer just filling in a few more registers in the sigcontext struct.  Can 
we do that?  Which registers would that be?

  //Johan