On Thu, Jan 24, 2019 at 11:24:37AM +0530, Sumit Garg wrote:
> This flag indicates that requests in this context should not wait for
> tee-supplicant daemon to be started if not present and just return
> with an error code. It is needed for requests which should be
> non-blocking in nature like ones arising from TEE based kernel drivers
> or any in kernel api that uses TEE internal client interface.
>
> Signed-off-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> ---
> drivers/tee/optee/supp.c | 10 +++++++++-
> drivers/tee/tee_core.c | 13 +++++++++++++
> include/linux/tee_drv.h | 6 ++++++
> 3 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
> index 43626e1..92f56b8 100644
> --- a/drivers/tee/optee/supp.c
> +++ b/drivers/tee/optee/supp.c
> @@ -88,10 +88,18 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
> {
> struct optee *optee = tee_get_drvdata(ctx->teedev);
> struct optee_supp *supp = &optee->supp;
> - struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
> + struct optee_supp_req *req;
> bool interruptable;
> u32 ret;
>
> + /*
> + * Return in case there is no supplicant available and
> + * non-blocking request.
> + */
> + if (!supp->ctx && ctx->supp_nowait)
> + return TEEC_ERROR_COMMUNICATION;
> +
> + req = kzalloc(sizeof(*req), GFP_KERNEL);
> if (!req)
> return TEEC_ERROR_OUT_OF_MEMORY;
>
> diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> index 9f4c8bc..2612dfa 100644
> --- a/drivers/tee/tee_core.c
> +++ b/drivers/tee/tee_core.c
> @@ -105,6 +105,11 @@ static int tee_open(struct inode *inode, struct file *filp)
> if (IS_ERR(ctx))
> return PTR_ERR(ctx);
>
> + /*
> + * Default user-space behaviour is to wait for tee-supplicant
> + * if not present for any requests in this context.
> + */
> + ctx->supp_nowait = false;
> filp->private_data = ctx;
> return 0;
> }
> @@ -981,6 +986,14 @@ tee_client_open_context(struct tee_context *start,
> } while (IS_ERR(ctx) && PTR_ERR(ctx) != -ENOMEM);
>
> put_device(put_dev);
> + /*
> + * Default behaviour for in kernel client is to not wait for
> + * tee-supplicant if not present for any requests in this context.
> + * Also this flag could be configured again before call to
> + * tee_client_open_session() if any in kernel client requires
> + * different behaviour.
> + */
> + ctx->supp_nowait = true;
> return ctx;
> }
> EXPORT_SYMBOL_GPL(tee_client_open_context);
> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> index ce957ce..56d7f1b 100644
> --- a/include/linux/tee_drv.h
> +++ b/include/linux/tee_drv.h
> @@ -50,6 +50,11 @@ struct tee_shm_pool;
> * @releasing: flag that indicates if context is being released right now.
> * It is needed to break circular dependency on context during
> * shared memory release.
> + * @supp_nowait: flag that indicates that requests in this context should not
> + * wait for tee-supplicant daemon to be started if not present
> + * and just return with an error code. It is needed for requests
> + * that arises from TEE based kernel drivers that should be
> + * non-blocking in nature.
> */
> struct tee_context {
> struct tee_device *teedev;
> @@ -57,6 +62,7 @@ struct tee_context {
> void *data;
> struct kref refcount;
> bool releasing;
> + bool supp_nowait;
> };
>
> struct tee_param_memref {
> --
> 2.7.4
>
