SDT_MEMRW
case SDT_MEMRW:
build_desc(&desc, ldt_base, PAGE_SIZE, SDT_MEMRW,
build_desc(&desc, ldt_base, PAGE_SIZE, SDT_MEMRW, SEL_KPL, 1, 0);
build_desc(&desc, ldt_base, PAGE_SIZE, SDT_MEMRW, SEL_UPL, 1, 0);
build_desc(&desc, ldt_base, PAGE_SIZE, SDT_MEMRW, SEL_UPL, 1, 0);
build_desc(&desc, ldt_base, PAGE_SIZE, SDT_MEMRW, SEL_UPL, 1, 0);