MAINTAINING SECURE DATA ISOLATED FROM NON-SECURE ACCESS WHEN SWITCHING BETWEEN DOMAINS

摘要

A data processing apparatus including circuitry for performing data processing, a plurality of registers; and a data store including regions having different secure levels, 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 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 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.

主权项

1. A data processing apparatus comprising:
processing circuitry configured to execute a stack select flag set instruction specifying a register and, in response to said select flag set instruction, to determine whether a target address that is stored in said register is in a less secure region of a data store than a current operating region, and when said target address is determined to be in said less secure region to set a stack select flag to indicate said less secure region.