Re: Arm-linux + TrustZone

On Fri, Jun 04, 2010 at 06:54:19PM +0100, Anandha Gopalan wrote:
> Q.1: It looks like the trustzone API has been incorporated into  
> Arm-Linux. From which version of Arm-linux is this included in? Does  
> this mean that device drivers are available for any ARM processor that  
> uses TrustZone. I know that to compile for the "trusted" part one needs  
> to use the RealView Development Suite (RVDS) of ARM.

We run the kernel in the secure world on ARM development platforms,
and the non-secure world on TI OMAP development platforms.  It is not
true that RVDS needs to be used; there's no real difference between
the secure world and non-secure world except that in the non-secure
world, various hardware registers are protected against reading or
change.

As for an API, Linux has no API implemented.  There is no defined API
for use with the 'SMC' (secure monitor call) instruction.  Every
secure monitor is different and implements its own API.  This makes it
exceedingly difficult when it comes to things like writing to protected
registers in order to work-around hardware bugs.