Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: A data processing system including a processor operable in a plurality of modes and in either a secure domain or a non-secure domain. The system includes at least one secure mode being a mode in the secure domain, at least one non-secure mode being a mode in the non-secure domain, and a monitor mode. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. Switching between the secure and non-secure modes takes place via the monitor mode and the processor is operable at least partially in the monitor mode to execute a monitor program managing switching between the secure and non-secure modes.

Abstract: A processor may utilise two operating systems (Non-Secure, Secure) between which calls may be made. In order that a second operating system can track task switches made by a first operating system, each time a call is made to the second operating system, this call includes an identifier to enable discrimination between the task which was executing on the first operating system when that call was made. The identifier can be a call identifier and/or a target thread identifier and may include further parameters.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: A processor may utilise two operating systems (Non-Secure, Secure) between which calls may be made. In order that a second operating system can track task switches made by a first operating system, each time a call is made to the second operating system, this call includes an identifier to enable discrimination between the task which was executing on the first operating system when that call was made. The identifier can be a call identifier and/or a target thread identifier and may include further parameters.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: In a data processing system using multiple operating systems, an interrupt which itself may be interrupted by a subsequent interrupt which will be serviced in a different operating system, guards itself against being overlooked when that subsequent interrupt has been handled by starting a stub interrupt handling routine in that other operating system before executing the main handling routine in the originating operating system. Thus, the stub interrupt handling routine will be recognised in the other operating system irrespective of other interrupt events which may occur and accordingly the interrupted interrupt handling may be restarted.

Abstract: A data processing system includes a processor that can operate in a plurality of modes and in either a secure domain or a non-secure domain. At least one secure mode is a mode in the secure domain, and at least one non-secure mode is a mode in the non-secure domain. When the processor is executing a program in a secure mode and that program has access to secure data which is not accessible when the processor is operating in a non-secure mode, the processor is responsive to exception conditions for triggering exception processing. Specifically, the processor is responsive to a parameter specifying which of the exceptions should be handled by a secure mode exception handler executing in a secure mode and which should be handled by an exception handler executing in a mode within a current one of the secure domain and the non-secure domain when that exception occurs.

Abstract: In a system supporting more than one operating system, a data processing thread executing on a first operating system may be subject to an interrupt which triggers interrupt handling on a second operating system. When that interrupt handling is completed on the second operating system, the first operating system is resumed using a return interrupt. The return interrupt specifies the data processing thread which is active on the second operating system such that an appropriate task switch or resumption may be made on the first operating system. The technique is particularly well suited to systems utilising a secure operating system and a non-secure operating system executing on the same hardware.

Abstract: There is a provided a data processing system comprising: a processor operable in a plurality of modes and either a secure domain or a non-secure domain including: at least one secure mode being a mode in said secure domain; and at least one non-secure mode being a mode in said non-secure domain; wherein when said processor is executing a program in a secure mode said program has access to secure data which is not accessible when said processor is operating in a non-secure mode; and wherein said processor is responsive to a switching request to initiate a switch between a secure mode and a non-secure mode under control of a mode switching program starting at a location specified by an exception vector associated with said switching request.

Abstract: An apparatus for processing data, the apparatus comprising: a processor operable in a plurality of modes and either a secure domain or a non-secure domain including at least one secure mode being a mode in the secure domain; and at least one non-secure mode being a mode in the non-secure domain. When the processor is executing a program in a secure mode, the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor further includes a non-secure translation table base address register and a secure translation table base address register operable in the non-secure and secure domain, respectively, to indicate a region of memory storing either non-secure or secure domain memory mapping data defining how virtual addresses are translated to physical addresses within either the non-secure or secure domain.

Abstract: A data processing apparatus is operable in a plurality of modes and in either a secure domain or a non-secure domain. When operating in a secure mode within the secure domain a program has access to secure data which is not accessible when the processor is operating in a non-secure mode. A vectored interrupt controller is provided to generate an exception handler address in response to an occurrence of an except condition. The vectored interrupt controller is programmable with parameters specifying for each exception condition whether an exception handler in the secure or the non-secure domain should be triggered and an exception handler address for use if the exception occurs when in the appropriate domain. The vectored interrupt controller also includes a parameter specifying a domain switching exception handler address for use if the exception condition occurs when the processor is not in the appropriate domain.

Abstract: Program instructions in the form of Java bytecodes may be subject to fixed mappings to processing operations or programmable mappings to processing operations. A system is provided with a fixed mapping hardware interpreter, a programmable mapping hardware interpreter and a software interpreter. The fixed mapping hardware interpreter is able to provide high speed interpretation of the common and simple bytecodes. The programmable mapping hardware interpreter is able to provide high speed interpretation of the simple and performance critical programmable bytecodes with the remaining bytecodes and more complicated bytecodes being handled by the software interpreter.

Abstract: A data processing system is provided with a first mechanism for executing instructions of a first instruction set and a second mechanism for executing instructions of a second instruction set. The second mechanism requires configuration data 310, 312, 314, 316 which may or may not be valid. Programs that use the second execution mechanism are responsible for the writing of its own configuration data with this being indicated as being necessary by a configuration valid indicator CV set to indicate that the configuration is invalid by the operating system 300 upon detecting an appropriate process switch.

Abstract: There is a provided a data processing system comprising:

Abstract: There is a provided apparatus for processing data, said apparatus comprising:

Abstract: In a data processing system using multiple operating systems, an interrupt which itself may be interrupted by a subsequent interrupt which will be serviced in a different operating system, guards itself against being overlooked when that subsequent interrupt has been handled by starting a stub interrupt handling routine in that other operating system before executing the main handling routine in the originating operating system. Thus, the stub interrupt handling routine will be recognised in the other operating system irrespective of other interrupt events which may occur and accordingly the interrupted interrupt handling may be restarted.

Abstract: There is a provided a data processing system comprising:

Abstract: In a system supporting more than one operating system, a data processing thread executing on a first operating system may be subject to an interrupt which triggers interrupt handling on a second operating system. When that interrupt handling is completed on the second operating system, the first operating system is resumed using a return interrupt. The return interrupt specifies the data processing thread which is active on the second operating system such that an appropriate task switch or resumption may be made on the first operating system. The technique is particularly well suited to systems utilising a secure operating system and a non-secure operating system executing on the same hardware.

Abstract: There is provided apparatus for processing data, said apparatus comprising: