Re: UVM and the NULL page

[Maxime Villard <max%m00nbsd.net@localhost>]

Le 30/07/2016 à 19:35, Thor Lancelot Simon a écrit :
> On Sat, Jul 30, 2016 at 07:12:31PM +0200, Joerg Sonnenberger wrote:
> > For what it is worth, I do believe that the handling of the 0 page
> > should be part of UVM and not pmap. I am only objection to forcing it
> > unconditionally.
>
> Perhaps I misunderstood, but I thought we were all already agreed that
> conditionalizing this upon a sysctl that could be set only when the
> system is at insecure runlevel was an acceptable thing to do.  I
> mean, that's *one read of an integer* per check; surely that must
> be acceptable -- Max?

My first proposion did not take care of the sysctl, because I didn't think it
was relevant. My last one does. Here is a patch for it. I believe it is safe
then to remove the va0_disable check in uvm_map.

	http://m00nbsd.net/garbage/uvm/execmin.diff