AN APPARATUS AND METHOD FOR MANAGING USE OF CAPABILITIES
First Claim
1. An apparatus comprising:
- processing circuitry to execute instructions, the processing circuitry being operable at a plurality of exception levels, each exception level having different software execution privilege;
a plurality of capability storage elements accessible to the processing circuitry and arranged to store capabilities used to constrain operations performed by the processing circuitry when executing said instructions; and
capability configuration storage to identify capability configuration information for each of said plurality of exception levels, for each exception level the capability configuration information identifying at least whether the operations performed by the processing circuitry when executing instructions at that exception level are constrained by said capabilities; and
during a switch operation from a source exception level to a target exception level, the capability configuration information in the capability configuration storage pertaining to at least one of the source exception level and the destination exception level is used to determine how execution state of the processing circuitry is managed during the switch operation.
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Accused Products
Abstract
An apparatus and method are provided for managing use of capabilities. The apparatus has processing circuitry to execute instructions, and a plurality of capability storage elements accessible to the processing circuitry and arranged to store capabilities used to constrain operations performed by the processing circuitry when executing instructions. The processing circuitry is operable at a plurality of exception levels, each exception level having different software execution privilege. Further, capability configuration storage is provided to identify capability configuration information for each of the plurality of exception levels. For each exception level, the capability configuration information identifies at least whether the operations performed by the processing circuitry when executing instructions at that exception level are constrained by capabilities. During a switch operation from a source exception level to a target exception level, the capability configuration information in the capability configuration storage pertaining to at least one of the source exception level and the destination exception level is used to determine how execution state of the processing circuitry is managed during the switch operation. This provides a great deal of flexibility in the management of capabilities.
1 Citation
24 Claims
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1. An apparatus comprising:
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processing circuitry to execute instructions, the processing circuitry being operable at a plurality of exception levels, each exception level having different software execution privilege; a plurality of capability storage elements accessible to the processing circuitry and arranged to store capabilities used to constrain operations performed by the processing circuitry when executing said instructions; and capability configuration storage to identify capability configuration information for each of said plurality of exception levels, for each exception level the capability configuration information identifying at least whether the operations performed by the processing circuitry when executing instructions at that exception level are constrained by said capabilities; and during a switch operation from a source exception level to a target exception level, the capability configuration information in the capability configuration storage pertaining to at least one of the source exception level and the destination exception level is used to determine how execution state of the processing circuitry is managed during the switch operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 23, 24)
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21. A method of managing use of capabilities within an apparatus having processing circuitry to execute instructions, the processing circuitry being operable at a plurality of exception levels, each exception level having different software execution privilege, and a plurality of capability storage elements accessible to the processing circuitry and arranged to store capabilities used to constrain operations performed by the processing circuitry when executing said instructions, the method comprising:
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identifying, within capability configuration storage, capability configuration information for each of said plurality of exception levels, for each exception level the capability configuration information identifying at least whether the operations performed by the processing circuitry when executing instructions at that exception level are constrained by said capabilities; and during a switch operation from a source exception level to a target exception level, using the capability configuration information in the capability configuration storage pertaining to at least one of the source exception level and the destination exception level to determine how execution state of the processing circuitry is managed during the switch operation.
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22. An apparatus comprising:
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processing means for executing instructions, the processing means being operable at a plurality of exception levels, each exception level having different software execution privilege; a plurality of capability storage element means accessible to the processing means and for storing capabilities used to constrain operations performed by the processing means when executing said instructions; and capability configuration storage means for identifying capability configuration information for each of said plurality of exception levels, for each exception level the capability configuration information identifying at least whether the operations performed by the processing means when executing instructions at that exception level are constrained by said capabilities; and during a switch operation from a source exception level to a target exception level, the capability configuration information in the capability configuration storage means pertaining to at least one of the source exception level and the destination exception level is used to determine how execution state of the processing means is managed during the switch operation.
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Specification