Interface: Ensure veneer function result return in dispatch
The tfm_ns_interface_dispatch() function returns TFM_ERROR_GENERIC
when mutex operations fails.
However, this error code could be interrepted by the caller as
another status code or even valid return.
For example the psa_connect() of NS interface, it treats the value
of TFM_ERROR_GENERIC a valid handle.
And the psa_call() could treat TFM_ERROR_GENERIC as another status
code of the RoT service.
In both cases, the TFM_ERROR_GENERIC is translated incorrectly.
The tfm_ns_interface_dispatch() should only return status code from
the veneer function being called. Other unrecoverable errors should
be considered as fatal error and should not return.
Change-Id: Id4082a46cd866acaba85aa63d10cfe46d09b3044
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
diff --git a/interface/include/tfm_ns_interface.h b/interface/include/tfm_ns_interface.h
index 21857be..1dd0692 100644
--- a/interface/include/tfm_ns_interface.h
+++ b/interface/include/tfm_ns_interface.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2017-2021, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*
@@ -31,6 +31,10 @@
* \param[in] arg3 Argument 3
*
* \return Returns the same return value of the requested veneer function
+ *
+ * \note This API must ensure the return value is from the veneer function.
+ * Other unrecoverable errors must be considered as fatal error and should
+ * not return.
*/
int32_t tfm_ns_interface_dispatch(veneer_fn fn,
uint32_t arg0, uint32_t arg1,