Date: Thu, 06 Dec 2001 08:51:41 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Ronald G Minnich <rminnich@lanl.gov> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: switching to real mode Message-ID: <3C0FA21D.86860C48@mindspring.com> References: <Pine.LNX.4.33.0112060930220.17486-100000@snaresland.acl.lanl.gov>
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Ronald G Minnich wrote: > > I saw an example of switching in real mode in linux' sources (it looks > > pretty clear) and thouhgt it is possible to do the same under FreeBSD. > > The problem is I'm absolutely lost in FreeBSD's physical memory management > > implementation (page tables and directory and so on). > > That code is quite broken. You need to check out the ones I mentioned > earlier. All that the code does in the linux kernel is fail badly. > > Actually there used to be in freebsd some really nice code for popping > into real mode and back again. It was to support calling BIOS for certain > things. It's still there. See the code in /sys/boot, in particular, the bios code in boot2 and boot 3. It isn't enough to do what he wants, though. He wants to effectively return to real mode and jump to a real mode boot strap loader, as if in the second stage of a boot manager, after the partition to boot has been selected (e.g. "Reboot to Linux", "Reboot to Windows", "Reboot to XXX"). I understand the desire now. It all depends on how much work he's willing to do. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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