Re: kprempt, pmap_load() and copy*

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
> > Hmmm.... lets see... thinks ...
> > copyin/out can fault or be interrupted, both can cause a process switch.
> > So there ought to be code somewhere (probably in the return from
> > trap/intr code) that will restore the pmap to allow the copy to
> > continue. This would rather indicate that the end of copyin/out ought
> > to be clearing a 'need process's pmap' flag.
> > Not looked ...
> 
> This is precisely this logic that I didn't find for the interrupt case.
> There is the onfault_table[] which contains critical sections and is used
> in trap() to know if the fault comes from one of the copy routines.
> It's not used outside of trap(), and wouldn't cover the case of
> interrupt in the copy routine but outside of the *_start/*_end labels.

http://nxr.netbsd.org/xref/src/sys/arch/amd64/amd64/trap.c?r=1.66#551

-- 
Mindaugas