Messages in this thread | | | Date | Mon, 09 Apr 2012 10:53:07 -0700 | From | "H. Peter Anvin" <> | Subject | Re: reboot via bios on X86_64? |
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On 04/09/2012 10:26 AM, Miles Fidelman wrote: > Thanks for the quick response. > > Matthew Garrett wrote: >> On Mon, Apr 09, 2012 at 11:39:32AM -0400, Miles Fidelman wrote: >> >>> 1. What's the logic behind this? Why not enable a bios reboot for 64bit >>> kernels? Is there any reason why the machine_real_restart code wouldn't >>> work just as well in 64bit mode? Anybody know the history? >> The bios reboot code requires you to reprogram the CPU to real mode. I >> don't think there's any fundamental reason you can't do that from 64-bit >> mode, but nobody's ever written that code. > > That would explain it. I guess there's a little bit of trickiness > involved in setting things up before > switching to real mode. >
Actually this code already exists; the difference is that we have to return to 32-bit mode first.
-hpa
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