3.2.3 Immutable Root of Trust (IRT) Region Features and Usage
IRT regions have access to features that are only accessible in IRT mode. Once IRT mode is exited, non-IRT mode cannot re-enter an IRT section. This prevents non-IRT code from accessing sensitive hardware features designated for the IRT operation. Attempts to access an IRT region from a non-IRT region are blocked. Access attempts from one IRT region to another IRT region are based on the permission settings of the target IRT region.
|
From IRT Region |
From Firmware Region | |
|---|---|---|
Read IRT Region | Based on target regions read permission setting | Generates an exception |
Write IRT Region | Based on target regions write permission setting | Generates a Flash operation error |
Jump to IRT region | Based on target regions execute permission setting | Generates an exception |