Re: Unifying /dev/{mem,kmem,zero,null} implementations

[Chris Gilbert <chris%dokein.co.uk@localhost>]

Joerg Sonnenberger wrote:
> Hi all,
> http://www.netbsd.org/~joerg/common-mem.diff
> unifies the implementation of /dev/{mem,kmem,zero,null} in MI code and
> makes it MPsafe. This is useful as writing to /dev/null is not that
> unknown :-)
>
> This needs quite a bit attention from portmasters and testing:
> - the address returned by mmap of /dev/mem is not consistent on all
> ports, I have no idea if it works on those where atop() doesn't exist.
> - on i386, the special /dev/io semantic for COMPAT_10 and COMPAT_FREEBSD
> is lost at the moment -- do we want to keep that? It would mean another
> platform hook.
> - the access permissions for raw memory are inconsistent and should be
> changed to use kauth on all platforms.
>
> Over all, the patch adds 1419 lines and removes 6271.
>
> Comments?
>
> Joerg
>   

In dev_mem_readwrite() pmap_kenter_pa and pmap_kremove calls require a 
pmap_update(pmap_kernel()) after them otherwise the updates may not have 
been sync'd into the hardware.

Thanks,
Chris