# Privilege mode

**URL:** <https://forums.freertos.org/t/privilege-mode/3458>\
**Category:** Kernel\
**Created:** [September 2, 2014, 9:39pm UTC](https://forums.freertos.org/t/privilege-mode/3458 "2014-09-02T21:39:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [September 2, 2014, 9:39pm UTC](https://forums.freertos.org/t/privilege-mode/3458/1 "2014-09-02T21:39:30Z")

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**[jmmifsud](https://sourceforge.net/u/jmmifsud/)** wrote on [Tuesday, September 02, 2014](https://sourceforge.net/p/freertos/discussion/382005/thread/97cc3a51/#9fed):

Hi,

I’m running FreeRtos on a Texas-Instruments RM48 (Cortex R4 core).  
When I try using the xTimer function, it is only working when the xTimer functions are called from main() before the vTaskStartScheduler(); or from callback routine.  
On this device the MPU is used to protect a portion of Flash and RAM for kernel usage.

All user task are running in user mode(non privilege mode) and so cannot use the xTimer API.

Can someone clarify or I’m doing something completly wrong.

Thanks in advance.

Jean-Marc

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [September 2, 2014, 10:35pm UTC](https://forums.freertos.org/t/privilege-mode/3458/2 "2014-09-02T22:35:21Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Tuesday, September 02, 2014](https://sourceforge.net/p/freertos/discussion/382005/thread/97cc3a51/#a319):

We don’t provide an MPU version of the Cortex-R port, so really it is a question for whoever supplied you the code - but if it is modeled on the Cortex-M MPU code then this is a known issue and is on the ‘known issues’ list. You can add the timer functions to the list of privileged functions relatively easily - if you search hard enough in this forum (you may be better off using the archive on the [FreeRTOS.org](http://FreeRTOS.org) webiste) you may find other discussions on this topic.

Regards.