How debug secured C6748 with DSP BIOS based application when exit mode is SECUREWITHSK

Dani Vain

Hi, we using generic secured C6748 for our project.

1. I experience an issue with debugging DSP BIOS based application when exiting in SECUREWITHSK boot exit mode.

2. I have no problem with debugging the above application when exiting in NONSECURE boot exit mode.

3. I have no problem with debugging application without DSP BIOS when exiting in SECUREWITHSK or NONSECURE boot exit mode.

4. I opened(unsecured) all MPUs and IOPUs.

5. In the scenario with DSP BIOS I noted that if I use "bios.GBL.USERINITFXN" (which is empty and do nothing for the test) option than the application stuck in the init routine.

From that I conclude that DSP get reset all the time, but I can't understand why.

I looked in "FLTSTAT" (value = 0x0E030210) register of the MPU2 and noted following :

Supervisor write fault (10h).
Privilege ID = DSP (1h).
Master ID = DSP CFG (3h).

I tried to clear the register to continue and didn't succeed, DSP continue to stuck between the c_init and the end of user init routine.

6. The above occures whenever "bios.GBL.ENABLE_SK = false" or bios.GBL.ENABLE_SK = true.

What I did wrong?

Dani.

P.S info of MPU2 register:

MPSAR 0x00000000

MPEAR 0xFFFFFFFF

MPPA 0x03FFFEFF

MPFAR 0x00000100

MPFSR 0x0C030210

over 12 years ago

0 Raja over 12 years ago

TI__Guru* 81335 points

Hi Dani,

Thanks for the post.

Debug the Secured Device:

Application development and debugging on a secure device is not really recommended but there is flexibility in the boot process that allow this functionality when required. The ini file for creation of secure boot images contains field called BootExitType and TAPCFG. Specifying the BootExit type as NONSECURE and TAPCFG= 0x0000FFFF will force the device to exit ROM boot in NON-secure mode and open the JTAG pins to connect the emulator.

Please refer the below wiki link for more detail.

http://processors.wiki.ti.com/index.php/Basic_Secure_Boot_for_OMAP-L138_C6748

0 Dani Vain over 12 years ago in reply to Raja

Intellectual 385 points

Hi, Thanks for the reply.

I am interesting in debugging the device in secured mode, I need to decrypt some encrypted modules.

Boot exit in NONSECURE mode will "lock" the secured kernel and it's API.

Dani.

0 Raja over 12 years ago in reply to Dani Vain

TI__Guru* 81335 points

Hi Dani,

The security aspect of things only come into play when you want to boot the device (and not when your program is actually running), I would recommend developing prototype boards with the non-secure version of the device so these can be used for application and system development without the complications of having to unlock the devices. Then the boot procedures can be later be finalized and tested on actual secure devices.

Please refer the below thread for the same.

http://e2e.ti.com/support/dsp/omap_applications_processors/f/42/p/119723/430670.aspx

Thanks.

0 Dani Vain over 12 years ago in reply to Raja

Intellectual 385 points

Thanks for the replay,

I actually trying to build some secondary boot loader that will boot firmware decrypted in form of decrypted modules.

I want to build the SBL using DSP BIOS.

Dani

P.S: Is it possible to change the interrupt vector table in device running in secured mode?

0 Rahul Prabhu over 12 years ago in reply to Dani Vain

TI__Guru** 116780 points

Dani,

It is not recommended to build the SBL using DSP BIOS. I would recommend that you create your secondary bootloader as a non-OS application and then pass control over to DSP BIOS application after switching to non-secure privileges.

Regards,

Rahul

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How debug secured C6748 with DSP BIOS based application when exit mode is SECUREWITHSK