On Sat, Aug 10, 2002 at 01:39:16PM -0400, Bill Sommerfeld wrote:

 > > I'd like to specify that exec mappings are not allowed to be entered
 > > via pmap_kenter_pa() (at least, not by machine-independent code).  I'm
 > > pretty sure no MI code does this as it stands.
 > 
 > What's the motivation/rationale for this restriction?  

Some systems don't have unused bits in the PTE to track exec permission,
and thus have to keep the info somewhere else (e.g. in a PV entry), which
aren't available to pmap_kenter_pa().  The goal is to avoid unnecessary
I-cache frobbing.

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>