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Date:   Thu, 20 Jan 2022 19:19:18 +0100
From:   Heiko Carstens <hca@linux.ibm.com>
To:     Heiko Carstens <hca@linux.ibm.com>
Cc:     Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Nico Boehr <nrb@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 01/10] s390/uaccess: Add storage key checked
 access to user memory
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On Thu, Jan 20, 2022 at 01:56:40PM +0100, Heiko Carstens wrote:
> > 2. Implementation changes
> >    2.1 Modify common code
> 
> In general such changes are done in way that common code is or _may_ be
> modified to fulfill our needs. Common code header file explicitely states
> that architectures should get rid of private instances of
> copy_{to,from}_user() and __copy_{to,from}_user{,_inatomic}().
> 
> So we should not add anything like that to arch code again, since nobody
> would expect that.

Or to be more specific: I think the most simple solution would be to
try to get the new *key variants into include/linux/uaccess.h, and add
the raw variants in architecture code, similar to the rest of the
uaccess functions.
There is some (sort of) prior art with copy_mc_to_kernel() even,
though that can only partially be compared.