Definition
Memory Protection
Memory protection controls memory access rights to prevent a process from accessing unallocated memory, ensuring system stability and security.
Mechanisms
Segmentation / Bounds
Hardware uses base and bound registers to ensure logical addresses stay within legal range.
Page Table Bits
Each page table entry contains control bits:
- Read/Write/Execute: Permission level
- User/Kernel: Restricts sensitive pages to Kernel Mode only
Protection Keys
Unique keys assigned to memory regions:
Frame-based: Each physical frame has a key. Process key must match frame key for access.
TLB-based: Each TLB entry has a key. CPU compares with Protection Key Registers. No match generates an exception.