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Soby Mathew authored
The TSP is expected to pass control back to EL3 if it gets preempted due to an interrupt while handling a Standard SMC in the following scenarios: 1. An FIQ preempts Standard SMC execution and that FIQ is not a TSP Secure timer interrupt or is preempted by a higher priority interrupt by the time the TSP acknowledges it. In this case, the TSP issues an SMC with the ID as `TSP_EL3_FIQ`. Currently this case is never expected to happen as only the TSP Secure Timer is expected to generate FIQ. 2. An IRQ preempts Standard SMC execution and in this case the TSP issues an SMC with the ID as `TSP_PREEMPTED`. In both the cases, the TSPD hands control back to the normal world and returns returns an error code to the normal world to indicate that the standard SMC it had issued has been preempted but not completed. This patch unifies the handling of these two cases in the TSPD and ensures that the TSP only uses TSP_PREEMPTED instead of separate SMC IDs. Also instead of 2 separate error codes, SMC_PREEMPTED and TSP_EL3_FIQ, only SMC_PREEMPTED is returned as error code back to the normal world. Background information: On a GICv3 system, when the secure world has affinity routing enabled, in 2. an FIQ will preempt TSP execution instead of an IRQ. The FIQ could be a result of a Group 0 or a Group 1 NS interrupt. In both case, the TSPD passes control back to the normal world upon receipt of the TSP_PREEMPTED SMC. A Group 0 interrupt will immediately preempt execution to EL3 where it will be handled. This allows for unified interrupt handling in TSP for both GICv3 and GICv2 systems. Change-Id: I9895344db74b188021e3f6a694701ad272fb40d4
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