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Which component will program TZASC?

Sahil

I have read in one ARM document

The TrustZone Address Space Controller (TZASC) is an AXI component which partitions its slave address range into a number of memory regions. The TZASC can be programmed by Secure software to configure these regions as Secure or Non-secure,
and will reject Non-secure transactions to a region that is configured as Secure.

In the highlighted statement it is written that "secure software" will we configuring TZASC.

I want to know that if secure software also includes "Trusted OS" or only Code running in EL3/monitor mode can configure the TZASC.

Thanks

Sahil

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    As the other replies say, any secure software /can/ program the TZASC because the only limit is the ability to generate secure bus transactions.

    In practice many systems will have a static configuration of the TZASC which would usually be done by firmware at boot (typically from EL3)

    Some advanced system will dynamically reconfigure the TZASC, effectively making the run time configuration of secure and non-secure regions possible.  This would probably be done from EL1.

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  • 0

    As the other replies say, any secure software /can/ program the TZASC because the only limit is the ability to generate secure bus transactions.

    In practice many systems will have a static configuration of the TZASC which would usually be done by firmware at boot (typically from EL3)

    Some advanced system will dynamically reconfigure the TZASC, effectively making the run time configuration of secure and non-secure regions possible.  This would probably be done from EL1.

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