>To partially answer my own question, the netbsd trap.c appears to
>cause a kernal panic if it gets a flag trap in user mode. a) this
>doesn't seem like a very good idea! User tasks shouldn't be able to
>panic the kernel so easilly.

I also took a quick look ... and I agree, it does look like a flag trap
will generate a kernel panic.  And I also agree that this is bad.  I
didn't have time to try it out and see if a user program could cause
that panic.  I'm sure trap processing is one place that could be improved
on the pc532 port.

> b) if my understanding is correct, why is
>ld.so generating the flag trap? When disassembled, this looks like
>"real" code rather than some garbage that just happens to be
>interpreted as a flag instruction, so it looks intentional.

I can't help you much here.  Matthias Pfaller is the one who got ld.so
working.  (leo@marco.de)

-- 
Phil Nelson
e-mail: phil@cs.wwu.edu
http://www.cs.wwu.edu/~phil