Arm Limited

Anthony Jebson

Michael Alexander Kennedy

Richard Roy Grisenthwaite

Matthew Lucien Evans

Andrew Christopher Rose

Ian Michael Caulfield

Andrew John Turner

Adam James McNeeney

Gareth James Evans

A data processing apparatus has a plurality of processors and a plurality of interrupt interfaces each for handling interrupt requests from a corresponding processor. An interrupt distributor controls routing of interrupt requests to the interrupt interfaces. A shared interrupt request is serviceable by multiple processors. In response to the shared interrupt request, a target interrupt interface issues an interrupt ownership request to the interrupt distributor, without passing the shared interrupt request to the corresponding processor, if it estimates that the corresponding processor is available for servicing the shared interrupt request. The shared interrupt request is passed to the corresponding processor when an ownership confirmation is received from the interrupt distributor indicating that the processor has been selected for servicing the shared interrupt request.

Handling interrupts in a multi-processor system

An interrupt controller for controlling the routing and handling of interrupts received at a data processing apparatus including at least one physical processing unit configured to run at least one of a plurality of virtual processors and a memory. The interrupt controller includes redistribution circuitry with at least one data store corresponding to the unit, the data store storing a pointer to a virtual pending table storing currently pending virtual interrupts for a virtual processor currently running on the corresponding unit and a pointer to a pending table configured to store currently pending physical interrupts for the corresponding unit and an input configured to receive a virtual interrupt for interrupting a virtual processor. Control circuitry is configured to add the virtual interrupt to the virtual pending table and to store the virtual interrupt in the virtual pending table for the virtual processor that is stored in the memory.

Handling and routing interrupts to virtual processors

A data processing device comprises a plurality of system registers and a set of interrupt handling registers for controlling handling of an incoming interrupt. The device also includes processing circuitry configured to execute software of the plurality of execution levels, and interrupt controller circuitry configured to route said incoming interrupts to interrupt handling software that is configured to run at one of said plurality of execution levels, and register access control circuitry configured to dynamically control access to at least some of said interrupt handling registers in dependence upon one of said plurality of execution levels that said incoming interrupt is routed to. The interrupt handling software configured to run at a particular execution level does not have access to interrupt handling registers for handling a different incoming interrupt that is routed to interrupt handling software that is configured to run at a more privileged execution level.

Method and apparatus for interrupt handling

A global interrupt number spaceis provided for use in message signalled interrupts. Interrupt destinationsare provided with pending interrupt cacheswith either backing storage provided by global pending status memoryshared by all the caches or separate individual pending status memories. The interrupt number space may be divided into regions with programmable mapping data being used to indicate which interrupt destinations are responsible for which regions. When interrupts are migrated from one interrupt destination to another, then such programmable mapping data is updated. Pending interrupts may be flushed back to the global pending status memoryduring the reassignment process such that this pending interrupt data may be picked up by the newly responsible interrupt destination.

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Cambridge, United Kingdom

Anthony Jebson