OPTEE's interrupt handling mechanism
Macro articles
The interrupt processing mechanism of OP-TEE (Open Portable Trusted Execution Environment) includes the following steps:
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Interrupt controller initialization: In OP-TEE, the interrupt controller needs to be initialized so that interrupts from external devices can be handled correctly. During the initialization process, parameters such as the interrupt vector table, interrupt priority, and interrupt enable of the interrupt controller need to be set .
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Registration of interrupt handlers: In OP-TEE, it is necessary to register an interrupt handler for each interrupt type. **When an interrupt occurs, the interrupt controller will call the corresponding interrupt handler to handle the interrupt. The interrupt processing function needs to perform corresponding processing according to the interrupt type, such as reading network data packets, updating timer counters, etc.
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Interrupt notification: When an interrupt occurs, OP-TEE will notify the core security monitor (Monitor) through the interrupt controller . Monitor is a key component in OP-TEE responsible for switching between the safe world and the normal world.
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Context switch: When an interrupt occurs, if the code in the normal world is currently being executed, Monitor will perform a context switch, transferring control to the OP-TEE operating system in the secure world to handle the interrupt**. This process includes saving the current processor state, loading the state of the secure world, and executing the exception handlers of the secure world. **
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Exception handling: The operating system of OP-TEE will call the corresponding exception handler to handle the interrupt. The exception handler will perform corresponding processing according to the interrupt type, such as reading network data packets, updating timer counters, etc. After processing the interrupt, the exception handler returns a result, which is captured and saved by the Monitor.