Date: Mon, 30 Aug 1999 23:02:47 -0700 From: "Neil Bradley" <neil@synthcom.com> To: <smp@freebsd.org> Subject: Re: BIOS calls on SMP systems Message-ID: <02d601bef376$74434a10$076291c6@Engineering.retrocade.com> References: <199908310542.WAA02756@dingo.cdrom.com>
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> > > Can someone familiar with the Intel MP spec clarify for me whether it's > > > permissible for an AP to call the BIOS, or whether only the BSP may do > > > this? > > It depends upon what services of the BIOS you're looking to call. If it's > > the standard INT services, only the BSP will be able to do it reliably. If > > you're calling the PCI functions, then you're most likely safe. But it is > > safe for the BSP to call BIOS even when the AP's aren't. > Ok, so the baseline answer is "only the BSP can reliably call the BIOS". Correct - but with a "depends" attached to it. What interrupt services are you calling? > Correct there? If so, I have some interesting tunneling work to do... Yes, but it depends upon what services you want to call in the BIOS. ON second thought, even doing 32 bit PCI function calls won't be safe because of the access to 0xcf8/0xcfc for configuration access. In other words, I wouldn't use the AP's to call BIOS services. -->Neil To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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