[PATCH] drm/stm: ltdc: limit number of layer to avoid memory overflow

[Benjamin Gaignard]

Le ven. 5 avr. 2019 à 18:30, Philippe CORNU <philippe.cornu at st.com> a écrit :
>
> Dear Yannick,
> Thank you for your patch,
>
> Acked-by: Philippe Cornu <philippe.cornu at st.com>
>

Applied on drm-misc-next,
Thanks,
Benjamin

> Philippe :)
>
> On 4/3/19 11:20 AM, Yannick Fertré wrote:
> > If the number of layer is greater than LTDC_MAX_LAYER, we can have
> > memory overflow when reading plane_fpsi[].
> >
> > Signed-off-by: Yannick Fertré <yannick.fertre at st.com>
> > ---
> >   drivers/gpu/drm/stm/ltdc.c | 7 +++++--
> >   1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> > index 32fd6a3..05bd4b6 100644
> > --- a/drivers/gpu/drm/stm/ltdc.c
> > +++ b/drivers/gpu/drm/stm/ltdc.c
> > @@ -1021,10 +1021,13 @@ static int ltdc_get_caps(struct drm_device *ddev)
> >       struct ltdc_device *ldev = ddev->dev_private;
> >       u32 bus_width_log2, lcr, gc2r;
> >
> > -     /* at least 1 layer must be managed */
> > +     /*
> > +      * at least 1 layer must be managed & the number of layers
> > +      * must not exceed LTDC_MAX_LAYER
> > +      */
> >       lcr = reg_read(ldev->regs, LTDC_LCR);
> >
> > -     ldev->caps.nb_layers = max_t(int, lcr, 1);
> > +     ldev->caps.nb_layers = clamp((int)lcr, 1, LTDC_MAX_LAYER);
> >
> >       /* set data bus width */
> >       gc2r = reg_read(ldev->regs, LTDC_GC2R);
> >
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