Add comment explaining the purpose of header
Explain why we have the wrappers in psa_memory_poisoning_wrappers.h
Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/tests/include/test/psa_memory_poisoning_wrappers.h b/tests/include/test/psa_memory_poisoning_wrappers.h
index 3422339..5192597 100644
--- a/tests/include/test/psa_memory_poisoning_wrappers.h
+++ b/tests/include/test/psa_memory_poisoning_wrappers.h
@@ -1,3 +1,9 @@
+/** Memory poisoning wrappers for PSA functions.
+ *
+ * These wrappers poison the input and output buffers of each function
+ * before calling it, to ensure that it does not access the buffers
+ * except by calling the approved buffer-copying functions.
+ */
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later