MEMORY PROTECTION IN A DATA PROCESSING SYSTEM
First Claim
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1. A method comprising:
- receiving a first memory access request from a first processor core at a system memory protection unit coupled to a plurality of processor cores including the first processor core, the first memory access request including a first address; and
determining at the system memory protection unit whether the first memory access request is allowed or denied; and
in response to determining the first memory access request is allowed, providing information for storage at a first cache line of a first cache of the first processor core, the information including first access permission information used by the system memory protection unit to determine whether the first memory access request is allowed or denied.
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Abstract
A system and method are disclosed for determining whether to allow or deny an access request based upon one or more descriptors at a local memory protection unit and based upon one or more descriptors a system memory protection unit. When multiple descriptors of a memory protection unit apply to a particular request, the least-restrictive descriptor will be selected. System access information is stored at a cache of a local core in response to a cache line being filled. The cached system access information is merged with local access information, wherein the most-restrictive access is selected.
17 Citations
20 Claims
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1. A method comprising:
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receiving a first memory access request from a first processor core at a system memory protection unit coupled to a plurality of processor cores including the first processor core, the first memory access request including a first address; and determining at the system memory protection unit whether the first memory access request is allowed or denied; and in response to determining the first memory access request is allowed, providing information for storage at a first cache line of a first cache of the first processor core, the information including first access permission information used by the system memory protection unit to determine whether the first memory access request is allowed or denied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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determining, based upon a first set of information local to a processor core, whether an access request of the processor core is allowed; and in response to determining the access request resulted in a cache hit at a cache of the processor core, further determining at the processor core based upon a second set of information stored at the cache whether the access request is allowed. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A system comprising:
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a first processor core including a first cache, the first processor core to generate a first memory access request; and a system memory protection unit to provide first information to be stored in a first cache line of the first cache in response to completion of the first memory access request, the first information including first access permission information determined at the system memory protection unit. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification