Re: [Qemu-devel] [PATCH] target-arm: Minimal implementation of performance counters

[Paul Brook]

> > I just spoke with Paul on IRC about this. In summary:
> >  * for a helper to cause an exception then it has (a) to make sure CPU
> >
> > state (pc, condflags) is sync'd before the call to the helper and (b)
> > the helper has to be in a file with access to global env, because it
> > needs to call cpu_loop_exit()
> 
> I don't think (a) is true. It is possible to use the same way as for
> load/store operations, that is call cpu_restore_state() before calling
> cpu_loop_exit().

To call cpu_restore_state you need to know searched_pc.  To find that you need 
to unwind the host stack all the way back to translated code.

Paul