Re: [PATCH v3] x86: treat pkey-0 special

On Thu, Mar 15, 2018 at 10:31:51AM -0700, Dave Hansen wrote:

On 03/15/2018 10:21 AM, Ram Pai wrote:

quoted

On Thu, Mar 15, 2018 at 08:55:31AM -0700, Dave Hansen wrote:

quoted

On 03/15/2018 02:46 AM, Thomas Gleixner wrote:

quoted

quoted

+	if (!pkey || !mm_pkey_is_allocated(mm, pkey))

Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true
ever. If it does, then this wants to be fixed.

I was thinking that we _do_ actually want it to seem allocated.  It just
get "allocated" implicitly when an mm is created.  I think that will
simplify the code if we avoid treating it specially in as many places as
possible.

I think, the logic that makes pkey-0 special must to go
in arch-neutral code.   How about checking for pkey-0 in sys_pkey_free()
itself?

This is for protection against shooting yourself in the foot?  Yes, that
can go in sys_pkey_free().

Does this need manpage and/or selftests updates?

Yes. it needs selftest, manpage and documentation updates too.

Unfortunately I am not getting enough reviewed-by for my selftests
and documentation changes. :-(  Need help!


-- 
Ram Pai