Re: I/O permission control in OSKit-Mach

[Roland McGrath]

> In German you would say that I have tomatoes on my eyes. ;)

You mean egg on your face? :-)

> Mmh.  What about i386_io_perm_modify vs. task_terminate on SMP?  I don't
> want to scribble in deallocated pages.  

Hmm, yes.  I think you want to task_lock while diddling it and check
TASK->active (like task_terminate itself does).

> Also, what about i386_io_perm_modify vs another cpu switching to another
> thread in the same task?  The bad kinds of interactions I am worried
> about is not so much the io_perm interface with itself, but with
> task_terminate on the one hand and the scheduler on the other hand.  Do I
> use a simple lock in the machine_task and make them all use it?

Yeah, that is probably what you need to do.  Needs some more though.
Stick in an XXX comment or a #warning #if NCPUS>1 and we can think about it
again when working on making SMP really work.