US Patent No. 10,169,573

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


Patent No. 10,169,573
Issue Date January 01, 2019
Title Maintaining Secure Data Isolated From Non-secure Access When Switching Between Domains
Inventorship Thomas Christopher Grocutt, Impington (GB)
Richard Roy Grisenthwaite, Guilden Morden (GB)
Assignee ARM Limited, Cambridge (GB)

Claim of US Patent No. 10,169,573

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;
wherein in response to program code calling a function stored in a first region of the data store, the processing circuitry is configured to access a first stack stored in the first region for function arguments and return data values when said stack select flag indicates the first region, and to access a second stack stored in a second region of the data store for the function arguments and the return data values when said stack select flag indicates the second region.