On Fri, Jun 28, 2019 at 05:57:26AM -0700, Rob Clark wrote:
> On Wed, Jun 26, 2019 at 7:05 PM Brian Masney <masneyb@xxxxxxxxxxxxx> wrote:
> >
> > Correct attempted NULL pointer dereference in context_init() when
> > running without an IOMMU.
> >
> > Signed-off-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
> > Fixes: 295b22ae596c ("drm/msm: Pass the MMU domain index in struct msm_file_private")
> > ---
> > The no IOMMU case seems like functionality that we may want to keep
> > based on this comment:
> > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/msm/adreno/a3xx_gpu.c#L523
> > Once I get the msm8974 interconnect driver done, I'm going to look into
> > what needs to be done to get the IOMMU working on the Nexus 5.
> >
> > Alternatively, for development purposes, maybe we could have a NOOP
> > IOMMU driver that would allow us to remove these NULL checks that are
> > sprinkled throughout the code. I haven't looked into this in detail.
> > Thoughts?
>
> yeah, we probably want to keep !iommu support, it is at least useful
> for bringup of new (or old) devices. But tends to bitrot a since it
> isn't a case that gets tested much once iommu is in place. Perhaps
> there is a way to have a null iommu/aspace, although I'm not quite
> sure how that would work..
>
> Anyways,
>
> Reviewed-by: Rob Clark <robdclark@xxxxxxxxx>
>
> (I guess this can go in via drm-misc-fixes unless we get some more
> fixes to justify sending msm-fixes MR..)
Applied to drm-misc-fixes for 5.3
Sean
>
> >
> > drivers/gpu/drm/msm/msm_drv.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> > index 451bd4508793..83047cb2c735 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.c
> > +++ b/drivers/gpu/drm/msm/msm_drv.c
> > @@ -619,7 +619,7 @@ static int context_init(struct drm_device *dev, struct drm_file *file)
> >
> > msm_submitqueue_init(dev, ctx);
> >
> > - ctx->aspace = priv->gpu->aspace;
> > + ctx->aspace = priv->gpu ? priv->gpu->aspace : NULL;
> > file->driver_priv = ctx;
> >
> > return 0;
> > --
> > 2.20.1
> >
> > _______________________________________________
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> > https://lists.freedesktop.org/mailman/listinfo/freedreno
--
Sean Paul, Software Engineer, Google / Chromium OS
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