tee: add supp_nowait flag in tee_context struct

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@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
index 43626e15703a80ddf48360c0622f37b813b76809..92f56b8645e353c456b6fddeba906eaa321374e9 100644 (file)
--- 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 7b2bb4c500580099a2f6e443da6fab9e4db7ae00..adf2588282fc57f48a5f3f493f18efc5d745e920 100644 (file)
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -106,6 +106,11 @@ 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;
 }
@@ -982,6 +987,14 @@ 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 6cfe05893a76b31280face250abc23e7ec9caaa6..5076502c07d761a019631fdc7a37c482f7bed87c 100644 (file)
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -47,6 +47,11 @@ 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;
@@ -54,6 +59,7 @@ struct tee_context {
        void *data;
        struct kref refcount;
        bool releasing;
+       bool supp_nowait;
 };
 
 struct tee_param_memref {