These objects are meant to be used by the GPU firmware or by the PM unit
within the GPU, in which case they may contain physical addresses.

This adds a layer of protection against exposing potentially exploitable
information outside of the driver.

Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
Signed-off-by: Alessio Belle <alessio.belle@imgtec.com>
---
 drivers/gpu/drm/imagination/pvr_gem.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/imagination/pvr_gem.c b/drivers/gpu/drm/imagination/pvr_gem.c
index a66cf082af24..c07c9a915190 100644
--- a/drivers/gpu/drm/imagination/pvr_gem.c
+++ b/drivers/gpu/drm/imagination/pvr_gem.c
@@ -28,6 +28,16 @@ static void pvr_gem_object_free(struct drm_gem_object *obj)
 	drm_gem_shmem_object_free(obj);
 }
 
+static struct dma_buf *pvr_gem_export(struct drm_gem_object *obj, int flags)
+{
+	struct pvr_gem_object *pvr_obj = gem_to_pvr_gem(obj);
+
+	if (pvr_obj->flags & DRM_PVR_BO_PM_FW_PROTECT)
+		return ERR_PTR(-EPERM);
+
+	return drm_gem_prime_export(obj, flags);
+}
+
 static int pvr_gem_mmap(struct drm_gem_object *gem_obj, struct vm_area_struct *vma)
 {
 	struct pvr_gem_object *pvr_obj = gem_to_pvr_gem(gem_obj);
@@ -42,6 +52,7 @@ static int pvr_gem_mmap(struct drm_gem_object *gem_obj, struct vm_area_struct *v
 static const struct drm_gem_object_funcs pvr_gem_object_funcs = {
 	.free = pvr_gem_object_free,
 	.print_info = drm_gem_shmem_object_print_info,
+	.export = pvr_gem_export,
 	.pin = drm_gem_shmem_object_pin,
 	.unpin = drm_gem_shmem_object_unpin,
 	.get_sg_table = drm_gem_shmem_object_get_sg_table,

---
base-commit: ca2583412306ceda9304a7c4302fd9efbf43e963
change-id: 20251128-no-export-pm-fw-obj-aeca634ddd0a

Best regards,
-- 
Alessio Belle <alessio.belle@imgtec.com>

On 08/12/2025 09:11, Alessio Belle wrote:
> These objects are meant to be used by the GPU firmware or by the PM unit
> within the GPU, in which case they may contain physical addresses.
> 
> This adds a layer of protection against exposing potentially exploitable
> information outside of the driver.
> 
> Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
> Signed-off-by: Alessio Belle <alessio.belle@imgtec.com>

Reviewed-by: Matt Coster <matt.coster@imgtec.com>

And I believe we want this to be:

Cc: stable@vger.kernel.org

Cheers,
Matt

> ---
>  drivers/gpu/drm/imagination/pvr_gem.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/imagination/pvr_gem.c b/drivers/gpu/drm/imagination/pvr_gem.c
> index a66cf082af24..c07c9a915190 100644
> --- a/drivers/gpu/drm/imagination/pvr_gem.c
> +++ b/drivers/gpu/drm/imagination/pvr_gem.c
> @@ -28,6 +28,16 @@ static void pvr_gem_object_free(struct drm_gem_object *obj)
>         drm_gem_shmem_object_free(obj);
>  }
> 
> +static struct dma_buf *pvr_gem_export(struct drm_gem_object *obj, int flags)
> +{
> +       struct pvr_gem_object *pvr_obj = gem_to_pvr_gem(obj);
> +
> +       if (pvr_obj->flags & DRM_PVR_BO_PM_FW_PROTECT)
> +               return ERR_PTR(-EPERM);
> +
> +       return drm_gem_prime_export(obj, flags);
> +}
> +
>  static int pvr_gem_mmap(struct drm_gem_object *gem_obj, struct vm_area_struct *vma)
>  {
>         struct pvr_gem_object *pvr_obj = gem_to_pvr_gem(gem_obj);
> @@ -42,6 +52,7 @@ static int pvr_gem_mmap(struct drm_gem_object *gem_obj, struct vm_area_struct *v
>  static const struct drm_gem_object_funcs pvr_gem_object_funcs = {
>         .free = pvr_gem_object_free,
>         .print_info = drm_gem_shmem_object_print_info,
> +       .export = pvr_gem_export,
>         .pin = drm_gem_shmem_object_pin,
>         .unpin = drm_gem_shmem_object_unpin,
>         .get_sg_table = drm_gem_shmem_object_get_sg_table,
> 
> ---
> base-commit: ca2583412306ceda9304a7c4302fd9efbf43e963
> change-id: 20251128-no-export-pm-fw-obj-aeca634ddd0a
> 
> Best regards,
> --
> Alessio Belle <alessio.belle@imgtec.com>
> 

-- 
Matt Coster
E: matt.coster@imgtec.com

On Mon, 08 Dec 2025 09:11:00 +0000, Alessio Belle wrote:
> These objects are meant to be used by the GPU firmware or by the PM unit
> within the GPU, in which case they may contain physical addresses.
> 
> This adds a layer of protection against exposing potentially exploitable
> information outside of the driver.
> 
> 
> [...]

Applied, thanks!

[1/1] drm/imagination: Disallow exporting of PM/FW protected objects
      commit: 6b991ad8dc3abfe5720fc2e9ee96be63ae43e362

Best regards,
-- 
Matt Coster <matt.coster@imgtec.com>