linux-kernel - Re: [PATCH] drm/rockchip: avoid 64-bit division

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241122-rebel-donkey-of-atheism-a0b8b6@houat>
Date: Fri, 22 Nov 2024 10:15:14 +0100
From: Maxime Ripard <mripard@...nel.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Nathan Chancellor <nathan@...nel.org>, Arnd Bergmann <arnd@...nel.org>, 
	Sandy Huang <hjc@...k-chips.com>, Heiko Stübner <heiko@...ech.de>, 
	Andy Yan <andy.yan@...k-chips.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Algea Cao <algea.cao@...k-chips.com>, 
	Cristian Ciocaltea <cristian.ciocaltea@...labora.com>, Arnd Bergmann <arnd@...db.de>, dri-devel@...ts.freedesktop.org, 
	linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/rockchip: avoid 64-bit division

On Fri, Nov 22, 2024 at 09:36:16AM +0100, Geert Uytterhoeven wrote:
> On Mon, Nov 4, 2024 at 6:30 PM Nathan Chancellor <nathan@...nel.org> wrote:
> > On Fri, Oct 18, 2024 at 03:10:10PM +0000, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@...db.de>
> > >
> > > Dividing a 64-bit integer prevents building this for 32-bit targets:
> > >
> > > ERROR: modpost: "__aeabi_uldivmod" [drivers/gpu/drm/rockchip/rockchipdrm.ko] undefined!
> > >
> > > As this function is not performance criticial, just Use the div_u64() helper.
> > >
> > > Fixes: 128a9bf8ace2 ("drm/rockchip: Add basic RK3588 HDMI output support")
> > > Signed-off-by: Arnd Bergmann <arnd@...db.de>
> >
> > Reviewed-by: Nathan Chancellor <nathan@...nel.org>
> >
> > Can someone please pick this up? It is still broken in next-20241104...
> >
> > https://storage.tuxsuite.com/public/clangbuiltlinux/continuous-integration2/builds/2oNvJFRj8tkDieb6VfrMf4rh1Kn/build.log
> >
> > > ---
> > >  drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> > > index 9c796ee4c303..c8b362cc2b95 100644
> > > --- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> > > +++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
> > > @@ -82,7 +82,7 @@ static void dw_hdmi_qp_rockchip_encoder_enable(struct drm_encoder *encoder)
> > >                * comment in rk_hdptx_phy_power_on() from
> > >                * drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
> > >                */
> > > -             phy_set_bus_width(hdmi->phy, rate / 100);
> > > +             phy_set_bus_width(hdmi->phy, div_u64(rate, 100));
> > >       }
> > >  }
> 
> noreply@...erman.id.au has just told me this build issue is now upstream:
> 
>     FAILED linus/m68k-allmodconfig/m68k-gcc8.1 Fri Nov 22, 05:34
>     http://kisskb.ellerman.id.au/kisskb/buildresult/15277242/
> 
>     Commit:   Merge tag 'drm-next-2024-11-21' of
> https://gitlab.freedesktop.org/drm/kernel
>               28eb75e178d389d325f1666e422bc13bbbb9804c
>     Compiler: m68k-linux-gcc (GCC) 8.1.0 / GNU ld (GNU Binutils) 2.30
> 
>     ERROR: modpost: "__udivdi3"
> [drivers/gpu/drm/rockchip/rockchipdrm.ko] undefined!
> 
> Applying this patch fixes it, so
> Acked-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> 
> Do we really need +5 weeks to apply a fix for a reported build issue?

Do we really need that kind of comments?

It was applied already, I made sure it's part of the next PR we send to
Linus. And it should be in linux-next tomorrow.

Maxime

Download attachment "signature.asc" of type "application/pgp-signature" (274 bytes)