Meaning
Hardware component that restricts memory access to defined regions protects the system from accidental or malicious overwriting. Embedded memory protection unit configurations define the boundaries between user code and kernel space to ensure that a task cannot interfere with the operating system. If a task attempts to read or write outside its assigned area, the unit triggers a hardware exception.
Region Definition
Blocks of memory are divided into several regions with specific permissions such as read only or no execute. The embedded memory protection unit allows an administrator to set these rules during the system boot phase. Each region has a start address and a size that must be aligned to specific hardware boundaries.
Memory Isolation
Isolation between different software modules is the primary goal of this hardware. If a driver has a bug that causes it to write to an invalid address, the embedded memory protection unit stops the write before it can corrupt other parts of the system. This prevents a single failure from causing a total system crash.
Access Exception
Violations result in an immediate trap to a high priority interrupt handler. The handler can then log the error and restart the offending task without affecting the rest of the product. This recovery mechanism is a requirement for many industrial safety standards.
