Messages in this thread | | | Subject | Re: [Fastboot] Re: kdump on non-boot cpu | From | (Eric W. Biederman) | Date | 07 Feb 2005 00:37:36 -0700 |
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Itsuro Oda <oda@valinux.co.jp> writes:
> > So I believe the fix needs to be to enable apics before we calibrate > > the delay timer. I'm not certain off the top of my head what that > > patch will look like but it should not be fundamentally hard. > > With that code in place we also don't need to do any APIC shutdown > > as the kernel knows enough to completely setup the apics. > > I see. Thank you for your explanation.
I have done a bit more digging.
For some reason, likely historical we don't initialize the IO_APIC in init_IRQ(). Instead we wait until smp_prepare_cpus() or smp_init(). Both functions are called much later in the init process than calibrate_delay().
Given the separation that has happened between apics and SMP it should be possible to initialize the local apic and the IO_APIC of the boot cpu much earlier in the game. It looks like it may take some heavy lifting though.
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