switch (aarch64_io.iov_len) {
	case sizeof(aarch64_regs):
		/* We are in 64-bit mode */
		scno = aarch64_regs.regs[8];
		update_personality(tcp, 1);
		break;
	case sizeof(arm_regs):
		/* We are in 32-bit mode */
		/* Note: we don't support OABI, unlike 32-bit ARM build */
		scno = arm_regs.ARM_r7;
		scno = shuffle_scno(scno);
		update_personality(tcp, 0);
		break;
}