> #define RETURN_PC(frameno) __builtin_return_address(frameno)
> 
> which gcc is turning into something involving a "ta 3".  But the trap

Cute..

I guess I'm going to turn that macro in a no-op for the sparc. Maybe this
particular trap can actually be handled without much fuss in kernel mode,
but I'm slowly beginning to dread these presumptuous ``__builtin_*''s.