sigaltstack setting and RT signal handlers

[Geoff Keating]

Paul Mackerras <paulus@samba.org> writes:

> Likewise, is it reasonable to expect that a signal handler can change
> the register values of the interrupted context by altering
> ucp->uc_mcontext?

Yes, in fact glibc uses this to set bits in the MSR.  I can think of
other applications for it involving virtual machines.

I'm not sure about the 'likewise' part.  There should be _a_ way for a
signal handler to change the sigaltstack setting, but since this is
not portable it doesn't have to be particularly clean.

-- 
- Geoffrey Keating <geoffk@geoffk.org>