GUGS_SEL
set_mem_segment(GDT_ADDR_MEM(gdtstore, GUGS_SEL), 0,
update_descriptor(&curcpu()->ci_gdt[GUGS_SEL], &zero);
update_descriptor(&curcpu()->ci_gdt[GUGS_SEL], &zero);
update_descriptor(&curcpu()->ci_gdt[GUGS_SEL], &pcb->pcb_gs);
update_descriptor(&ci->ci_gdt[GUGS_SEL], &pcb->pcb_gs);
update_descriptor(&ci->ci_gdt[GUGS_SEL], &zero);
(((s) & 0xffff) == GSEL(GUGS_SEL, SEL_UPL))
update_descriptor(&ci->ci_gdt[GUGS_SEL],
tf->tf_gs = GSEL(GUGS_SEL, SEL_UPL);
tf->tf_gs = GSEL(GUGS_SEL, SEL_UPL);
if (info.entry_number != GUGS_SEL) {
info.entry_number = GUGS_SEL;
update_descriptor(&curcpu()->ci_gdt[GUGS_SEL], &usd);
setusergs(GSEL(GUGS_SEL, SEL_UPL));
tf->tf_gs = GSEL(GUGS_SEL, SEL_UPL);