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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 5 Dec 2019 12:27:08 +0200
Message-ID: <CAHp75VfXc88Fa6=zs=9iToz27QdXHqRCDPQwBPs2P-rsBF8nHw@mail.gmail.com>
Subject: Re: [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes
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To:     Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc:     Bartosz Golaszewski <brgl@bgdev.pl>,
        Kent Gibson <warthog618@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Dec 5, 2019 at 11:42 AM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:
> =C5=9Br., 4 gru 2019 o 23:34 Andy Shevchenko <andy.shevchenko@gmail.com> =
napisa=C5=82(a):
> > On Wed, Dec 4, 2019 at 6:03 PM Bartosz Golaszewski <brgl@bgdev.pl> wrot=
e:

> > > +struct gpioline_info_changed {
> > > +       __u64 timestamp;
> > > +       __u32 event_type;
> > > +       struct gpioline_info info;
> > > +       __u32 padding[4]; /* for future use */
> > > +};
> >
> > Has this been tested against 64-bit kernel / 32-bit userspace case?
> >
>
> No. Since this is a new thing - do you think it's possible to simply
> arrange the fields or add padding such that the problem doesn't even
> appear in the first place?

Yes. this can be done, though be careful about potential endianess
issues (the ABI must be tested on BE as well).

So, the test cases, I can imagine of, should include (k - kernel, u - user)=
:
- 64k-64u: LE and BE
- 64k-32u: LE and BE
- 32k-32u: LE and BE

--=20
With Best Regards,
Andy Shevchenko