Re: [PATCH 3/3] drm/pl111: depend on CONFIG_VEXPRESS_CONFIG

From: Kees Cook <keescook@chromium.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Rob Herring <robh@kernel.org>, Dave Airlie <airlied@redhat.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@linux.ie>, Arnd Bergmann <arnd@kernel.org>,
	kernel test robot <lkp@intel.com>,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Emma Anholt <emma@anholt.net>, Rob Clark <robdclark@gmail.com>,
	Sean Paul <sean@poorly.run>,
	Sharat Masetty <smasetty@codeaurora.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	freedreno <freedreno@lists.freedesktop.org>
Subject: Re: [PATCH 3/3] drm/pl111: depend on CONFIG_VEXPRESS_CONFIG
Date: Thu, 3 Jun 2021 14:48:02 -0700	[thread overview]
Message-ID: <202106031447.09F7AE9EE4@keescook> (raw)
In-Reply-To: <CAKMK7uG8ZiToP2vFsr7TuhntWWh0yiaHkwU5mx5EaESoy+tTHQ@mail.gmail.com>

On Thu, Jun 03, 2021 at 11:41:01PM +0200, Daniel Vetter wrote:
> On Thu, Jun 3, 2021 at 11:29 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > On Thu, Jun 03, 2021 at 02:19:52PM -0700, Kees Cook wrote:
> > > On Thu, Jun 03, 2021 at 09:19:42PM +0200, Daniel Vetter wrote:
> > > > On Thu, Jun 3, 2021 at 8:43 PM Rob Herring <robh@kernel.org> wrote:
> > > > >
> > > > > On Wed, Jun 2, 2021 at 4:53 PM Kees Cook <keescook@chromium.org> wrote:
> > > > > >
> > > > > > Avoid randconfig build failures by requiring VEXPRESS_CONFIG:
> > > > > >
> > > > > > aarch64-linux-gnu-ld: drivers/gpu/drm/pl111/pl111_versatile.o: in function `pl111_vexpress_clcd_init':
> > > > > > pl111_versatile.c:(.text+0x220): undefined reference to `devm_regmap_init_vexpress_config'
> > > > >
> > > > > pl111_vexpress_clcd_init() starts with:
> > > > >
> > > > > if (!IS_ENABLED(CONFIG_VEXPRESS_CONFIG))
> > > > >                 return -ENODEV;
> > > > >
> > > > > Isn't that supposed to be enough to avoid an undefined reference?
> > >
> > > Ah! I missed that when reading the code. I see the problem now. It's
> > > because of:
> > >
> > > CONFIG_VEXPRESS_CONFIG=m
> > > CONFIG_DRM_PL111=y
> > >
> > > I think the right fix is:
> > >
> > > diff --git a/drivers/gpu/drm/pl111/Kconfig b/drivers/gpu/drm/pl111/Kconfig
> > > index 80f6748055e3..662fc38f92ba 100644
> > > --- a/drivers/gpu/drm/pl111/Kconfig
> > > +++ b/drivers/gpu/drm/pl111/Kconfig
> > > @@ -3,6 +3,7 @@ config DRM_PL111
> > >       tristate "DRM Support for PL111 CLCD Controller"
> > >       depends on DRM
> > >       depends on ARM || ARM64 || COMPILE_TEST
> > > +     depends on VEXPRESS_CONFIG=y || VEXPRESS_CONFIG=DRM
> >
> > Oops, no, I had this backwairds:
> >
> >         depends on !VEXPRESS_CONFIG || VEXPRESS_CONFIG=DRM
> 
> Can you pls throw this into an incremental patch on top of
> drm-misc-next? It's a non-rebasing tree and all that (linux-next
> should have it next day too I guess).

Ah! Yes, sorry. I wasn't sure if you'd reverted it yet. One moment...

-Kees

-- 
Kees Cook