Arm Limited

Viswanath Chakrala

Andrew Brookfield Swaine

Stuart David Biles

Zheng Xu

Guanghui Geng

Timothy Nicholas Hay

Abdul Ghani Kanawati

Thomas Franz Gaertner

Ghani Kanawati

Apparatus for data processing and a method of data processing are provided. Address translation storage stores address translations between first set addresses and second set addresses, and responds to a request comprising a first set address to return a response comprising a second set address if the required address translation is currently stored therein. If it is not the request is forwarded towards memory in a memory hierarchy. A pending request storage stores entries for received requests and in response to reception of the request, if a stored entry for a previous request indicates that the previous request has been forwarded towards the memory and an expected response to the previous request will provide the address translation, intercepts the request to delay its reception by the address translation storage. Bandwidth pressure on the address translation storage is thus relieved.

Address translation in a data processing apparatus

Circuitry comprises attribute storage circuitry having a plurality of entries to hold data defining at least a transaction attribute of one or more respective data handling transactions initiated by transaction source circuitry; comparator circuitry to compare a transaction attribute of a given data handling transaction with data held by the attribute storage circuitry to detect whether the given data handling transaction would be resolved by any data handling transaction for which attribute data is held by a respective entry in the attribute storage circuitry; and control circuitry to associate the given data handling transaction with the respective entry in the attribute storage circuitry to form a set of associated data handling transactions when the comparator circuitry detects that the given data handling transaction would be fulfilled by the data handling transaction for which attribute data is held by the respective entry in the attribute storage circuitry; the control circuitry comprising output circuitry responsive to a resolution of a data handling transaction in the set of associated data handling transactions, to provide that resolution to the transaction source circuitry as a resolution of each of the set of associated transactions.

Circuitry and method

An apparatus and method of operating the apparatus are disclosed, where the apparatus has translation circuitry to perform translations of input data to generate a translation response comprising translated data. The translation is performed in dependence on translation configuration data stored in data storage. A processing element determines an associated error detection code in dependence on the input data and on the translated data, and causes the translation configuration data and the associated error detection code to be stored in the data storage. When translation of the input data is performed by the translation circuitry the translation configuration data and its associated error detection code are retrieved from the data storage and the input data is translated into the translated data in dependence on the translation configuration data. A verification error detection code is calculated in dependence on the input data and on the translated data. A difference between the associated error detection code and the verification error detection code triggers an error in the translation response.

Translation protection in a data processing apparatus

A data processing systemincorporates a translation buffer unitand a translation control unit. The translation buffer unit responds to receipt of a memory access transaction for which translation data is unavailable in that translation buffer unit by issuing a request to the translation control unit to provide translation data for the memory access transaction. The translation control unit is responsive to disabling or enabling of address translation for a given type of memory access transaction to an issue invalidate command to all translation buffer units which may be holding translation data for that given type of memory access transaction. When the translation control unit receives a request for translation from the translation buffer unit for a memory access of the given type for which memory address translation is disabled, then the translation control unit responds to returning global translation data to be used by the translation buffer for all memory access translations of that given type.

Translation buffer unit management

A data processing apparatus having a memory configured to store tables having virtual to physical address translations, a cache configured to store a subset of the virtual to physical address translations and cache management circuitry configured to control transactions received from the processor requesting virtual address to physical address translations. The data processing apparatus identifies where a faulting transaction has occurred during execution of a context and whether the faulting transaction has a transaction stall or transaction terminate fault. The cache management circuitry is responsive to identification of the faulting transaction having a transaction terminate fault to invalidate all address translations in the cache that relate to the context of the faulting transaction such that a valid bit associated with each entry in the cache is set to invalid for the address translations.

Growing community of inventors

Sheffield, United Kingdom

Viswanath Chakrala