Hi Stefan, > Thanks for your answer. While in short term we are actually working with > imx53 which is a single core your assumption holds of course. Still I am > worried about the impact of IQs and FIQs that might disturb us while > consuming or writing data in both (secure and normal) worlds. In long > term we would like to even move on to a multi core plattform. > > So as far as I see it, I think in our case it is unfortunately not that > easy. We can not just assume implicit synchronisation through TrustZone > being either in secure or normal world at a time, but interrupts (and > later the multi core arch) will make our life harder. Please correct me > if I am wrong here (would be happy to be wrong, to be honest).
I don't think that interrupts are a concern here. As long as the tz_vmm is active with processing an SMC, normal-world interrupts are masked. The normal world will receive its next interrupt not before tz_vmm has finished its work. On a multi-processor system, each CPU can be in the normal or secure world independently. Hence, it would be sensible to use a dedicated tz_vmm handler with a separate shared memory buffer for each CPU. Alternatively, the normal-world OS may synchronize SMC calls similar to how it usually synchronizes the access to a peripheral device. Neither of both designs would require mutex-based synchronization between the secure and normal world. Could I clear up your doubts a bit? ;-) Best regards Norman -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
