MPU Task Creation Check Region Settings

[Skptak]

Description

This is a POC of how to remove the PRIVILEGED_DATA and PRIVILEGED_FUNCTIONS MPU Regions from the FreeRTOS-Kernel. This is done by inspecting the MPU settings a task is attempting to be created with to determine if it is:

1. Trying to grant itself write permissions to FLASH
2. Trying to grant itself execute permissions to RAM
3. Trying to grant itself read/write to PRIVILEGED_FLASH/PRIVILEGED_DATA when being created as an unprivileged task

There are additional checks for invalid MPU settings as well, to assist end-users when creating MPU enabled tasks.

Test Steps

1. Modify a task's MPU settings to attempt to grant write permissions to FLASH
2. Modify a task's MPU settings to attempt to grant execute permissions to RAM
3. Modify an unprivileged task's MPU Settings to attempt to grant permissions to PRIVILEGED_FLASH/PRIVILEGED_DATA

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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