Trace Hook Macros and MPU

Kernel
1

Hello,

I am a university student and I am investigating security hardening capabilities on FreeRTOS for my thesis. I am planning to use an MPU to separate the kernel and application code into privileged and unprivileged regions.

During runtime, I would like to collect timing metadata for every task execution using the traceTASK_SWITCH_IN and traceTASK_SWITCHED_OUT macros (e.g. by using a high-precision hardware timer peripheral) and store the calculated execution time in a privileged section of memory. I was wondering if these macros are being executed within the privileged context of the scheduler which would enable me to do this.

2

Yes, that is how it is typically done. You may want to try Tracealyzer from Percepio (my company). This is free for academic use, just apply for an academic license.

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3

Yes, these macros are called from vTaskSwitchContext which executes with elevated privilege. So you should be able to track timing as you proposed. Let us know if you face any problem.

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