Is unrecoverable_exception() really an interrupt handler ?

[Christophe Leroy]

Hi Nick,

You defined unrecoverable_exeption() as an interrupt handler in interrupt.h

I think there are several issues around that:

- do_bad_slb_fault() which is also an interrupt handler calls unrecoverable_exeption()
- in exception-64s.S, unrecoverable_exeption() is called after machine_check_exception()
- interrupt_exit_kernel_prepare() calls unrecoverable_exception()

So in those cases, interrupt_enter_prepare() gets called twice, so things like for instance 
account_cpu_user_entry() gets called twice.

Christophe