SNVS in non-secure state

kevi49 · ‎07-08-2022

I have enabled the SNVS in kernel

And I am checking the log in dmesg and it is showing that

"caam-snvs 20cc000.caam-snvs: violation handlers armed - non-secure state"

So, how to secure it?

What steps I need to follow?

kevi49 · ‎07-11-2022

Thank you for answer.

I have one query regarding the tamper detection in LP mode.

#define SNVS_HPSICR 0xc
#define SNVS_HPSICR_VALUE 0x80000035

#define SNVS_LPTGFCR 0x44
#define SNVS_LPTGFCR_VALUE 0x800000

#define SNVS_LPTDCR 0x48
#define SNVS_LPTDCR_VALUE 0xa00

#define SNVS_LPZMK 0x6c
#define SNVS_LPZMK_VALUE 0x12345678

#define SNVS_LPSR 0x4c
#define SNVS_LPSR_RESET_VALUE 0x7f0

#define SNVS_TAMPER 0xa4
#define SNVS_TAMPER_RESET_VALUE 0xff

Step 1: Configured all above register.

Step 2: Disconnected the main power supply, and device is now operating in LP mode with coin cell.

Step 3: Press the tamper switch.

Step 4: Again turn the board on with main power source(HP Mode).

Step 5: Reading the register SNVS_LPSR(4c) value to check if tamper bit 9(ET1D) if set or not.

Step 6: But it showing always 0, even after tamper switch is press.

All above configuration working properly in HP mode(After pressing switch if I read the SNVS_LPSR(4c) it showing tamper bit 9(ET1D) is set).

So, what is the wrong here,Why I am not able to see the bit is set in LP mode(After removing main power source).

Bio_TICFSL · ‎07-08-2022

Hello,

Please refer to section 6.3.1.1 (Transitioning among system security monitor states)

of the i.MX6 Security Reference Manual.

Regards

Have a great day,