Task State Segment - Location of The TSS

Location of The TSS

The TSS may reside anywhere in memory. A special segment register called the task register (TR) holds a segment selector that points to a valid TSS segment descriptor which resides in the GDT (a TSS descriptor may not reside in the LDT). Therefore, to use a TSS the following must be done by the operating system kernel:

1. Create a TSS descriptor entry in the GDT
2. Load the TR with a segment selector for that segment
3. Add information to the TSS in memory as needed

For security purposes, the TSS should be placed in memory that is accessible only to the kernel.