From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control
 the tagged user addresses ABI
Date: Tue, 18 Jun 2019 10:18:12 +0100
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To: Kees Cook <keescook@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>, Mark Rutland <mark.rutland@arm.com>, kvm@vger.kernel.org, Christian Koenig <Christian.Koenig@amd.com>, Szabolcs Nagy <Szabolcs.Nagy@arm.com>, Will Deacon <will.deacon@arm.com>, dri-devel@lists.freedesktop.org, Kostya Serebryany <kcc@google.com>, Khalid Aziz <khalid.aziz@oracle.com>, Lee Smith <Lee.Smith@arm.com>, linux-kselftest@vger.kernel.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Jacob Bramley <Jacob.Bramley@arm.com>, Leon Romanovsky <leon@kernel.org>, linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig <hch@infradead.org>, Jason Gunthorpe <jgg@ziepe.ca>, Dmitry Vyukov <dvyukov@google.com>, Evgeniy Stepanov <eugenis@google.com>, linux-media@vger.kernel.org, Ruben
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On Thu, Jun 13, 2019 at 10:13:54PM -0700, Kees Cook wrote:
> On Thu, Jun 13, 2019 at 04:26:32PM +0100, Catalin Marinas wrote:
> > On Thu, Jun 13, 2019 at 12:02:35PM +0100, Dave P Martin wrote:
> > > On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > > > +static int zero;
> > > > +static int one = 1;
> > > 
> > > !!!
> > > 
> > > And these can't even be const without a cast.  Yuk.
> > > 
> > > (Not your fault though, but it would be nice to have a proc_dobool() to
> > > avoid this.)
> > 
> > I had the same reaction. Maybe for another patch sanitising this pattern
> > across the kernel.
> 
> That's actually already happening (via -mm tree last I looked). tl;dr:
> it ends up using a cast hidden in a macro. It's in linux-next already
> along with a checkpatch.pl addition to yell about doing what's being
> done here. ;)
> 
> https://lore.kernel.org/lkml/20190430180111.10688-1-mcroce@redhat.com/#r

Hmmm, that is marginally less bad.

Ideally we'd have a union in there, not just a bunch of void *.  I may
look at that someday...

Cheers
---Dave