- * The thread_struct.fs and thread_struct.gs values are 0
- * if the fs and gs bases respectively are not overridden
- * from the values implied by fsindex and gsindex. They
- * are nonzero, and store the nonzero base addresses, if
- * the bases are overridden.
- *
- * (fs != 0 && fsindex != 0) || (gs != 0 && gsindex != 0) should
- * be impossible.
- *
- * Therefore we need to reload the segment registers if either
- * the old or new selector is nonzero, and we need to override
- * the base address if next thread expects it to be overridden.
- *
- * This code is unnecessarily slow in the case where the old and
- * new indexes are zero and the new base is nonzero -- it will
- * unnecessarily write 0 to the selector before writing the new
- * base address.
- *
- * Note: This all depends on arch_prctl being the only way that
- * user code can override the segment base. Once wrfsbase and
- * wrgsbase are enabled, most of this code will need to change.