linux-kernel - Re: [PATCH] drm/imagination: Disallow exporting of PM/FW protected objects

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Message-ID: <689cc5d9-4258-4355-bd7a-69e1413c018e@imgtec.com>
Date: Thu, 18 Dec 2025 15:37:01 +0000
From: Matt Coster <Matt.Coster@...tec.com>
To: Alessio Belle <Alessio.Belle@...tec.com>
CC: Frank Binns <Frank.Binns@...tec.com>,
        Alexandru Dadu
	<Alexandru.Dadu@...tec.com>,
        Maarten Lankhorst
	<maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Christian König <christian.koenig@....com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "linaro-mm-sig@...ts.linaro.org" <linaro-mm-sig@...ts.linaro.org>
Subject: Re: [PATCH] drm/imagination: Disallow exporting of PM/FW protected
 objects

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@...tec.com>

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

And I believe we want this to be:

Cc: stable@...r.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@...tec.com>
> 

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


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