alignment exceptionhandler sleeps in invalid context

[Paul Mackerras]

Kumar Gala writes:

> I was going to ask how this was actually hit.  It seems odd that we  
> would have an alignment error in the network stack.  From the oops  
> can we determine what the instruction was that faulted and what  
> address it was trying to access.

No, it's not particularly odd, given that our get_unaligned() and
put_unaligned() in include/asm-powerpc/unaligned.h just do a single
access.  That makes the common case (address is actually aligned, or
cpu handles it in hardware) fast at the expense of occasionally taking
an alignment exception.

Paul.