Messages in this thread | | | Date | Mon, 9 Apr 2012 16:51:55 +0100 | From | Matthew Garrett <> | Subject | Re: reboot via bios on X86_64? |
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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.
> 2. Anybody know a workaround, short of patching and compiling a custom > kernel? Are there other paths through the reboot code that can > invoke a bios > reboot? [Note: someone suggested trying a kexec-reboot, but that's also > not supported on my configuration (running over a Xen hypervisor).]
Windows never uses the equivalent of the BIOS reboot method, so the assumption is that if you ever need on Linux to it's because there's a bug somewhere else. Does the platform reboot if you run the kernel on bare metal rather than under Xen?
-- Matthew Garrett | mjg59@srcf.ucam.org
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