drm/vc4: Add an API for creating GPU shaders in GEM BOs.
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.
v2: Use __u32-style types.
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/include/uapi/drm/vc4_drm.h b/include/uapi/drm/vc4_drm.h
index 219d34c..74de184 100644
--- a/include/uapi/drm/vc4_drm.h
+++ b/include/uapi/drm/vc4_drm.h
@@ -28,9 +28,11 @@
#define DRM_VC4_CREATE_BO 0x03
#define DRM_VC4_MMAP_BO 0x04
+#define DRM_VC4_CREATE_SHADER_BO 0x05
#define DRM_IOCTL_VC4_CREATE_BO DRM_IOWR(DRM_COMMAND_BASE + DRM_VC4_CREATE_BO, struct drm_vc4_create_bo)
#define DRM_IOCTL_VC4_MMAP_BO DRM_IOWR(DRM_COMMAND_BASE + DRM_VC4_MMAP_BO, struct drm_vc4_mmap_bo)
+#define DRM_IOCTL_VC4_CREATE_SHADER_BO DRM_IOWR(DRM_COMMAND_BASE + DRM_VC4_CREATE_SHADER_BO, struct drm_vc4_create_shader_bo)
/**
* struct drm_vc4_create_bo - ioctl argument for creating VC4 BOs.
@@ -65,4 +67,27 @@
__u64 offset;
};
+/**
+ * struct drm_vc4_create_shader_bo - ioctl argument for creating VC4
+ * shader BOs.
+ *
+ * Since allowing a shader to be overwritten while it's also being
+ * executed from would allow privlege escalation, shaders must be
+ * created using this ioctl, and they can't be mmapped later.
+ */
+struct drm_vc4_create_shader_bo {
+ /* Size of the data argument. */
+ __u32 size;
+ /* Flags, currently must be 0. */
+ __u32 flags;
+
+ /* Pointer to the data. */
+ __u64 data;
+
+ /** Returned GEM handle for the BO. */
+ __u32 handle;
+ /* Pad, must be 0. */
+ __u32 pad;
+};
+
#endif /* _UAPI_VC4_DRM_H_ */