Re: [PATCH 4/9] drm/vc4: Add an API for creating GPU shaders in GEM BOs.

[Emil Velikov]

Hi Eric,

On 1 December 2015 at 20:35, Eric Anholt <eric@xxxxxxxxxx> wrote:
> Since we have no MMU, the kernel needs to validate that the submitted
> shader code won't make any accesses to memory that the user doesn't
> control, which involves banning some operations (general purpose DMA
> writes), and tracking where we need to write out pointers for other
> operations (texture sampling).  Once it's validated, we return a GEM
> BO containing the shader, which doesn't allow mapping for write or
> exporting to other subsystems.
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/vc4/Makefile               |   3 +-
>  drivers/gpu/drm/vc4/vc4_bo.c               | 140 ++++++++
>  drivers/gpu/drm/vc4/vc4_drv.c              |   9 +-
>  drivers/gpu/drm/vc4/vc4_drv.h              |  50 +++
>  drivers/gpu/drm/vc4/vc4_qpu_defines.h      | 264 +++++++++++++++

May I suggest that one 'exports' the header to something like
libdrm_vc4 ? There are patches in flight for nouveau which in similar
fashion, allow userspare to reuse existing api/abi.

-Emil
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