[PATCH 3/7] powerpc/mm: Add a framework for Kernel Userspace Access Protection

[Mark Rutland]

On Thu, Feb 21, 2019 at 11:46:06AM +0100, Christophe Leroy wrote:
> 
> 
> Le 21/02/2019 à 10:35, Russell Currey a écrit :
> > From: Christophe Leroy <christophe.leroy at c-s.fr>
> > 
> > This patch implements a framework for Kernel Userspace Access
> > Protection.
> > 
> > Then subarches will have to possibility to provide their own
> > implementation by providing setup_kuap() and lock/unlock_user_access()
> > 
> > Some platform will need to know the area accessed and whether it is
> > accessed from read, write or both. Therefore source, destination and
> > size and handed over to the two functions.
> 
> Should we also consider adding user_access_begin() and the 3 other
> associated macros ?
> 
> See x86 for details.

As a heads-up, there are some potential issues with
user_access_{begin,end}() that may affect PPC. There's a long thread
starting at:

https://lkml.kernel.org/r/1547560709-56207-4-git-send-email-julien.thierry@arm.com/

Thanks,
Mark.