| 摘要 |
A data processing system is provided with at least one processor 4, 6, a main memory 18 and a cache memory 14. Cache data within the cache memory 14 has validity data V and control data associated with it. The control data controls access to the cached data. Program instructions executed by the processors 4, 6 control a cache controller 26 to modify the control data associated with the cached data whilst it remains stored within the cache memory 14 and remains valid. The control data may, specify a security flag indicating whether access is restricted to secure processes or processors. The control data may be TAG data and/or program thread specifying data. The processors may have different access states and the main memory may have a controlled region which is accessible only by a processor running in an authorised access state. The control data in the cache may mark cached data as controlled data cached by a processor in an authorised access state to be accessed only by that processor. The processor may change the control data if the access status of the data is changed. |
