Invoking TA Failed When Using OPTEE on Juno r1

Hi experts,

The day before yesterday I posted a question about using OPTEE of Juno and Ash Wilding has replied me once.

It looks like the post has lost on the new ARM Community website while I still got another error I can't solve so I would describe my question here.

I used the script from using-linaro-s-deliverables-on-juno with the choice "Juno, Build from source, Linux/Android, lsk-4.4" for getting the system source code.

I built the system and the system could be run on the Juno platform.

However, when I was trying the hello world example from Linaro lcu14_optee_hello_world I met an error.

For the system configuration:

1. I saved the TA in the folder /lib/optee_armtz/ (for previous version it's /lib/teetz/).
2. I didn't insmod any "*.ko" because I didn't find any one in my workspace after I built the system.
3. I could run the command ./export/bin/tee-supplicant & successfully so I assume above modules are not necessary.

The problem is, when I ran the client part of the example, I could see the output:

Invoking TA to increment 42

However, after that, I got the error:

ERR [2098] TEEC:TEEC_InvokeCommand:567: TEE_IOC_INVOKE failed
hello_world: TEEC_InvokeCommand failed with code 0xffff0000 origin 0x2

For the TrustZone part, I got the following debug info when running the example:

DEBUG: [0x0] TEE-CORE:tee_ta_init_static_ta_session:160: Lookup for Static TA 8aaaf200-2450-11e4-abe20002a5d5c51b 
DEBUG: [0x0] TEE-CORE:init_session_with_signed_ta:716: Load dynamic TA 
DEBUG: [0x0] TEE-CORE:ta_load:497: Loaded TA at 0xff200000 
DEBUG: [0x0] TEE-CORE:ta_load:498: ELF load address 0x40001000 
DEBUG: [0x0] TEE-CORE:init_session_with_signed_ta:722: dyn TA : 8aaaf200-2450-11e4-abe20002a5d5c51b 
DEBUG: [0x0] TEE-CORE:tee_ta_close_session:318: tee_ta_close_session(0xff05bf20) 
DEBUG: [0x0] TEE-CORE:tee_ta_close_session:337: ... Destroy session 
DEBUG: [0x0] TEE-CORE:tee_ta_close_session:358: ... Destroy TA ctx

So far, I have no idea how's this error happens.

The only reason I could come out with is that I didn't load the optee.ko or optee_armtz.ko while I can't find any existing ko file for loading within the current version.

Please check my issue and let me know if you have any suggestion about debug this problem.

Thank you very much.

Simon