| 摘要 |
A data processing apparatus comprising: data processing circuitry for performing data processing operations in response to program code; a plurality of registers; and a data store for storing data, the data store comprising a plurality of regions having different secure levels, and comprising at least one secure region for storing sensitive data accessible by the data processing circuitry operating in the secure domain and not accessible by the data processing circuitry operating in a less secure domain and a less secure region for storing less secure data. The data store comprises at least two stacks a secure stack in the secure region and a less secure stack in the less secure region. The data processing circuitry operates in the secure domain when processing program code stored in the secure region and operates in the less secure domain when processing program code stored in the less secure region; wherein the data processing circuitry is configured to determine which stack to store data to, or load data from, in response to the storage location of the program code being executed. In response to program code stored, in a first region calling a function to be executed, the function code being stored in a second region, the second region having a different secure level to the first region, the data processing circuitry is configured to determine which of the first and second region have a lower secure level and when executing the program code and the function code, to access the stack of the region with the lower secure level for function arguments and return data values. |
