On Wed, Aug 30, 2017 at 09:44:53AM +0200, Daniel Vetter wrote:
On Tue, Aug 29, 2017 at 05:03:19PM +0100, Brian Starkey wrote:
On Fri, Aug 25, 2017 at 03:34:33PM +0200, Daniel Vetter wrote:
> On Thu, Aug 24, 2017 at 11:04:01AM +0100, Brian Starkey wrote:
> > Hi,
> >
> > Thanks for the CC.
> >
> > On Fri, Aug 18, 2017 at 06:13:14PM +0200, Noralf Tr??nnes wrote:
> > > (cc affected parties)
> > >
> > >
> > > Den 18.08.2017 09.46, skrev Daniel Vetter:
> > > > On Thu, Aug 17, 2017 at 06:21:30PM +0200, Noralf Tr??nnes wrote:
> > > > > Reject mapping an imported dma-buf since is's an invalid use-case.
> > > > >
> > > > > Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > > > > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > > > > Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > > > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > > > > Signed-off-by: Noralf Tr??nnes <noralf@xxxxxxxxxxx>
> > > > I think acks from someone using mali would be good too. amdgpu already has
> > > > such checks, so I think on the desktop side we're ok.
> > > >
> >
> > This looks like it would break anyone running the Mali-4xx series GPUs
> > with the Arm graphics stack (e.g. Hikey board).
> >
> > I don't know where that sits in terms of policy.
>
> Why would this break this use-case? Is the mali blob somehow using dumb
> mmap for it's own buffers it shares with display? That would be rather
> backwards ...
If it's running with a DRM display driver (which may or may not be
Mali-DP, they are separate IPs), then its window system code always
uses dumb mmap if it needs a pointer. That might be a native DRM
buffer that the display driver allocated, or a dma-buf which it PRIME
imported (which would now fail).
Yeah, that's pretty much the kind of uabi abuse I want to prevent. Dumb
mmap is for dumb buffers, if you have a egl platform then you need to mmap
through that one anyway. If a egl stack uses dumb mmap, something went
wrong somewhere.
But it exists. There's applications depending on that behaviour to
continue working, so shouldn't it continue to work? I thought that
was rule #1
-Brian
-Daniel
-Brian
>
> Either way, blob -> meh, not a concern really.
> -Daniel
>
> >
> > Cheers,
> > -Brian
> >
> > > > Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > > >
> > > > But I think this one here definitely needs a few more acks. I could break
> > > > uabi if we're unlucky, so let's not rush it.
> > >
> > > Ok, I've CC'ed the affected parties to increase the odds that they look
> > > at this. These are the drivers using drm_gem_dumb_map_offset()
> > > (hopefully I got the list right):
> > >
> > > arc
> > > atmel-hlcdc
> > > cirrus
> > > exynos
> > > fsl-dcu
> > > gma500
> > > hdlcd
> > > imx
> > > kirin
> > > mali-dp
> > > mediatek
> > > meson
> > > mxsfb
> > > pl111
> > > rcar-du
> > > rockchip
> > > shmobile
> > > sti
> > > stm
> > > sun4i
> > > tegra
> > > tilcd
> > > vc4
> > > zte
> > >
> > >
> > > Noralf.
> > >
> > > > -Daniel
> > > >
> > > > > ---
> > > > > drivers/gpu/drm/drm_gem.c | 6 ++++++
> > > > > 1 file changed, 6 insertions(+)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > > > > index ad4e9cf..8da5801 100644
> > > > > --- a/drivers/gpu/drm/drm_gem.c
> > > > > +++ b/drivers/gpu/drm/drm_gem.c
> > > > > @@ -333,6 +333,12 @@ int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
> > > > > if (!obj)
> > > > > return -ENOENT;
> > > > > + /* Don't allow imported objects to be mapped */
> > > > > + if (obj->import_attach) {
> > > > > + ret = -EINVAL;
> > > > > + goto out;
> > > > > + }
> > > > > +
> > > > > ret = drm_gem_create_mmap_offset(obj);
> > > > > if (ret)
> > > > > goto out;
> > > > > --
> > > > > 2.7.4
> > > > >
> > >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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