TZASC misconfiguration on i.mx8m

[Ye Li]

Hi Richard,

On 6/5/2026 10:52 PM, Richard Weinberger wrote:
> CC'ing Ye Li.
> 
> On Donnerstag, 4. Juni 2026 19:24 Richard Weinberger wrote:
>> Hello!
>>
>> FYI, in arch/arm/mach-imx/imx8m/soc.c enable_tzc380() U-Boot configures
>> region0 to allow secure and non-secure world access.
>> This is known to be problematic and allows circumventing the TrustZone due to
>> memory aliasing[0][1].
>>
>> It causes also recent OP-TEE to panic at startup:
>> E/TC:0 0 Panic 'region0 is not secure configured, non-secure memory alias access possible!' at core/arch/arm/plat-imx/tzc380.c:217 <imx_configure_tzasc>
>>
>> This is not a theoretical issue.
>> On my i.mx8mm evk Board I was able to exploit this and dump all OP-TEE memory from Linux.
> 
> I suggest reverting commit b3cf0a8f03d162e030cde1131751d060853e16fc
> Author: Ye Li <ye.li at nxp.com>
> Date:   Tue Aug 27 06:25:34 2019 +0000
> 
>      imx8m: Configure trustzone region 0 for non-secure access
>      
>      Set trustzone region 0 to allow both non-secure and secure access
>      when trust zone is enabled. We found USB controller fails to access
>      DDR if the default region 0 is secure access only.
>      
>      Signed-off-by: Ye Li <ye.li at nxp.com>
>      Signed-off-by: Peng Fan <peng.fan at nxp.com>
> 
> Thanks,
> //richard
We have discussed this with iMX optee owner. The fix should be done in 
OPTEE not u-boot.
1. OPTEE uses secure memory, so it needs to re-confiure trustzone to 
meet secure requirement not depending on SPL setting.
2. SPL also supports Non-optee case.

Best regards,
Ye Li
>