• State TI Thinks Resolved
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 19 views
  • Users 0 members are here
Support feedback
Options
Options
Related

AM263PX-RESTRICTED-SECURITY: User Mode vs supervisior mode

Sravya Kalluri
Prodigy 195 points

Part Number: AM263PX-RESTRICTED-SECURITY

Hi Team , 

I have a question regarding the usage of User mode vs Supervisor mode in MPU/firewall settings, specifically for L2OCRAM_BANK0_SLV.

My understanding is that Supervisor mode is typically required for privileged operations such as modifying hardware peripheral registers or performing system-level configuration changes.

However, in the case of memory regions like L2OCRAM_BANK0_SLV , what is the practical purpose of enabling or restricting Supervisor mode access?

Is Supervisor mode intended only for peripheral register protection, or does it also have a broader meaning in the context of memory regions such as OCRAM?

Could you please explain:

  1. Why Supervisor/User mode distinction is needed for MPU-controlled memory regions like OCRAM.
  2. Typical use cases where Supervisor-only access is enabled for RAM regions.
  3. Whether this is mainly for OS/kernel protection, safety/security isolation, or some other purpose.

I would appreciate some clarification on the architectural intent behind this access control.

  • 0
    TI__Guru* 88911 points

    Hi Sravya,

    As per the MPU firewall section in TRM

    So the supervisor and user mode is inherited from the processor's state.

    If the R5F is running in privileged mode (e.g., FreeRTOS tasks by default run privileged on bare-metal), the bus transaction is marked as Supervisor. and If running in User mode (e.g., an unprivileged RTOS task), the transaction is marked as User.

    If you have an RTOS (or Autosar) with unprivileged tasks (User mode), you can restrict those tasks from accessing certain OCRAM regions (e.g., kernel stacks, secure data)
    by only enabling Supervisor access.

    Thanks and Regards,

    Nikhil Dasan