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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 7 Jun 2022 12:22:41 +0200
Message-ID: <CAMuHMdXb5-gOVRsQx6tDqjQMD9cC-p=o56VuF2cBPWyMFRgHMA@mail.gmail.com>
Subject: Re: [git pull] drm for 5.19-rc1
To:     Dave Airlie <airlied@gmail.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>
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Hi Dave.

On Wed, May 25, 2022 at 4:49 PM Dave Airlie <airlied@gmail.com> wrote:
>       drm/amdgpu: add nbio v7_7_0 ip headers

These header files are heavy users of large constants lacking the "U"
suffix e.g.:

    #define NB_ADAPTER_ID__SUBSYSTEM_ID_MASK 0xFFFF0000L

Assigning this to unsigned long on 32-bit will trigger a signed integer
overflow, which is technically UB, and causes "error: initializer
element is not constant" warnings with gcc-5 and -std-gnu11, cfr. [1]

While gcc-5 is old, the fact that this is UB will probably start to
bite us one day...

[1] https://lore.kernel.org/r/CAK8P3a0QrihBR_2FQ7uZ5w2JmLjv7czfrrarCMmJOhvNdJ3p9g@mail.gmail.com

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds