Re: [PATCH 16/22] gpu: host1x: Forbid unrelated SETCLASS opcode in the firewall

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On Tue, May 23, 2017 at 02:39:33AM +0200, Erik Faye-Lund wrote:
> On Tue, May 23, 2017 at 2:14 AM, Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Several channels could be made to write the same unit concurrently via the
> > SETCLASS opcode, trusting userspace is a bad idea. It should be possible to
> > drop the per-client channel reservation and add a per-unit locking by
> > inserting MLOCK's to the command stream to re-allow the SETCLASS opcode, but
> > it will be much more work. Let's forbid the unit-unrelated class changes for
> > now.
> >
> > Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > ---
> >  drivers/gpu/drm/tegra/drm.c  |  1 +
> >  drivers/gpu/drm/tegra/drm.h  |  1 +
> >  drivers/gpu/drm/tegra/gr2d.c | 12 ++++++++++++
> >  drivers/gpu/host1x/job.c     | 24 ++++++++++++++++++++----
> >  include/linux/host1x.h       |  5 ++++-
> >  5 files changed, 38 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> > index cdb05d6efde4..17416e1c219a 100644
> > --- a/drivers/gpu/drm/tegra/drm.c
> > +++ b/drivers/gpu/drm/tegra/drm.c
> > @@ -531,6 +531,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> >         }
> >
> >         job->is_addr_reg = context->client->ops->is_addr_reg;
> > +       job->is_valid_class = context->client->ops->is_valid_class;
> >         job->syncpt_incrs = syncpt.incrs;
> >         job->syncpt_id = syncpt.id;
> >         job->timeout = 10000;
> > diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> > index 85aa2e3d9d4e..6d6da01282f3 100644
> > --- a/drivers/gpu/drm/tegra/drm.h
> > +++ b/drivers/gpu/drm/tegra/drm.h
> > @@ -83,6 +83,7 @@ struct tegra_drm_client_ops {
> >                             struct tegra_drm_context *context);
> >         void (*close_channel)(struct tegra_drm_context *context);
> >         int (*is_addr_reg)(struct device *dev, u32 class, u32 offset);
> > +       int (*is_valid_class)(u32 class);
> >         int (*submit)(struct tegra_drm_context *context,
> >                       struct drm_tegra_submit *args, struct drm_device *drm,
> >                       struct drm_file *file);
> > diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
> > index 02cd3e37a6ec..782231c41a1a 100644
> > --- a/drivers/gpu/drm/tegra/gr2d.c
> > +++ b/drivers/gpu/drm/tegra/gr2d.c
> > @@ -109,10 +109,22 @@ static int gr2d_is_addr_reg(struct device *dev, u32 class, u32 offset)
> >         return 0;
> >  }
> >
> > +static int gr2d_is_valid_class(u32 class)
> > +{
> > +       switch (class) {
> > +       case HOST1X_CLASS_GR2D:
> > +       case HOST1X_CLASS_GR2D_SB:
> > +               return 1;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> >  static const struct tegra_drm_client_ops gr2d_ops = {
> >         .open_channel = gr2d_open_channel,
> >         .close_channel = gr2d_close_channel,
> >         .is_addr_reg = gr2d_is_addr_reg,
> > +       .is_valid_class = gr2d_is_valid_class,
> >         .submit = tegra_drm_submit,
> >  };
> >
> > diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
> > index cf335c5979e2..65e12219405a 100644
> > --- a/drivers/gpu/host1x/job.c
> > +++ b/drivers/gpu/host1x/job.c
> > @@ -358,6 +358,9 @@ struct host1x_firewall {
> >
> >  static int check_register(struct host1x_firewall *fw, unsigned long offset)
> >  {
> > +       if (!fw->job->is_addr_reg)
> > +               return 0;
> > +
> >         if (fw->job->is_addr_reg(fw->dev, fw->class, offset)) {
> >                 if (!fw->num_relocs)
> >                         return -EINVAL;
> > @@ -372,6 +375,19 @@ static int check_register(struct host1x_firewall *fw, unsigned long offset)
> >         return 0;
> >  }
> >
> > +static int check_class(struct host1x_firewall *fw, u32 class)
> > +{
> > +       if (!fw->job->is_valid_class) {
> > +               if (fw->class != class)
> > +                       return -EINVAL;
> > +       } else {
> > +               if (!fw->job->is_valid_class(fw->class))
> > +                       return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> >  static int check_mask(struct host1x_firewall *fw)
> >  {
> >         u32 mask = fw->mask;
> > @@ -445,11 +461,9 @@ static int validate(struct host1x_firewall *fw, struct host1x_job_gather *g)
> >  {
> >         u32 *cmdbuf_base = (u32 *)fw->job->gather_copy_mapped +
> >                 (g->offset / sizeof(u32));
> > +       u32 job_class = fw->class;
> >         int err = 0;
> >
> > -       if (!fw->job->is_addr_reg)
> > -               return 0;
> > -
> >         fw->words = g->words;
> >         fw->cmdbuf = g->bo;
> >         fw->offset = 0;
> > @@ -469,7 +483,9 @@ static int validate(struct host1x_firewall *fw, struct host1x_job_gather *g)
> >                         fw->class = word >> 6 & 0x3ff;
> >                         fw->mask = word & 0x3f;
> >                         fw->reg = word >> 16 & 0xfff;
> > -                       err = check_mask(fw);
> > +                       err = check_class(fw, job_class);
> > +                       if (!err)
> > +                               err = check_mask(fw);
> >                         if (err)
> >                                 goto out;
> >                         break;
> > diff --git a/include/linux/host1x.h b/include/linux/host1x.h
> > index aa323e43ae4e..561d6bb6580d 100644
> > --- a/include/linux/host1x.h
> > +++ b/include/linux/host1x.h
> > @@ -233,7 +233,10 @@ struct host1x_job {
> >         u8 *gather_copy_mapped;
> >
> >         /* Check if register is marked as an address reg */
> > -       int (*is_addr_reg)(struct device *dev, u32 reg, u32 class);
> > +       int (*is_addr_reg)(struct device *dev, u32 class, u32 reg);
> 
> This seems like an unrelated fix, you might want to mention it in the
> commit message at least.

If you're going to rev the series anyway, might be worth splitting this
off into a separate commit to make it stand out more.

Either way is fine with me.

Thierry

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