About S32K312 MPU Background Region

[sunyy]

Hi all, I have a question about S32K312 MPU Background Region:

For example, setting permissions for a certain address: region1：permissions are readable and executable in privileged mode and readable and executable in user mode; So the permissions within the address area of region 1 are readable and executable in privileged mode and readable and executable in user mode; The access permissions for address segments other than region 1 are:

1.If the Background Region is enabled, the permissions for other address segments are: readable , writable, and executable under privileged mode, and not readable , writable, and executable under user mode?

2. If the Background Region is not enabled, what are the permissions for other address segments: not readable, not writable, and not executable under privileged mode and user mode?

Best regards.

[danielmartynek]

Hi @sunyy,

https://developer.arm.com/documentation/dui0646/c/Cortex-M7-Peripherals/Optional-Memory-Protection-U...

https://developer.arm.com/documentation/dui0646/c/Cortex-M7-Peripherals/Optional-Memory-Protection-U...

Regards,

Daniel

[sunyy]

Hello，What are the read and write access permissions for the background region?

[danielmartynek]

Hello @sunyy,

This is specified in the documentation I linked here.

The background region has the same memory access attributes as the default memory map, but is accessible from privileged software only.

Please contact ARM support if you need more details.

Regards,

Daniel

[sunyy]

Thank you for your answer.
But I couldn't find a specific description of read and write permissions, so I would like to ask if the permissions for the background region are read and write in privileged mode and not read and write in user mode, right?

[danielmartynek · Accepted solution]

Hi @sunyy,

As per the description, default memory map has read/write in both privileged and not-privileged modes. The background region has read/write in privileged mode only.

Please contact ARM support if you need more datails.

Regrads,

Daniel