GUFS_SEL
set_mem_segment(GDT_ADDR_MEM(gdtstore, GUFS_SEL), 0,
update_descriptor(&curcpu()->ci_gdt[GUFS_SEL], &zero);
update_descriptor(&curcpu()->ci_gdt[GUFS_SEL], &zero);
update_descriptor(&curcpu()->ci_gdt[GUFS_SEL], &pcb->pcb_fs);
update_descriptor(&ci->ci_gdt[GUFS_SEL], &pcb->pcb_fs);
update_descriptor(&ci->ci_gdt[GUFS_SEL], &zero);
(((s) & 0xffff) == GSEL(GUFS_SEL, SEL_UPL))
update_descriptor(&ci->ci_gdt[GUFS_SEL],
tf->tf_fs = GSEL(GUFS_SEL, SEL_UPL);
tf->tf_fs = GSEL(GUFS_SEL, SEL_UPL);
update_descriptor(&curcpu()->ci_gdt[GUFS_SEL], &usd);
tf->tf_fs = GSEL(GUFS_SEL, SEL_UPL);