OpenBSD/sgi on octane2 - TLBとARCBIOS

sys/arch/sgi/sgi/machdep.cより。
tlbをフラッシュしてしまうとARCBIOSにアクセス出来なくなるかもしれない、という事のようだ。

	/*
	 * Last chance to call the BIOS. Wiping the TLB means the BIOS' data
	 * areas are demapped on most systems. O2s are okay as they do not have 
	 * mapped BIOS text or data.
	 */
	delay(20*1000);		/* Let any UART FIFO drain... */

	sys_config.cpu[0].tlbwired = UPAGES / 2;
	tlb_set_wired(0);
	tlb_flush(sys_config.cpu[0].tlbsize);
	tlb_set_wired(sys_config.cpu[0].tlbwired);