> > Hi Eric,
> >
> > There is another problem with that patch - it broke ES7000, I kept
> > getting timer panics. It turned out that check_timer() runs
> before the
> > actual APIC destination is set up. The IO-APIC uses
> > cpu_to_logical_apicid to find the destination - which needs
> > cpu_2_logical_apicid[] to be filled - which only happens after
> > processors are booted. At the time when check_timer() runs, it will
> > always be BAD_APICID (0xFF - broadcast) as the IO-APIC rte
> destination
> > for the timer, but ES7000 hardware happened not to support
> 0xFF so it
> > panics. I used bios_cpu_apicid[] to bring it up, but
> > cpu_to_logical_apicid is the only one that is kept
> up-to-date in the
> > hotplug case, so I cannot replace it in the cpu_mask_to_apicid().
> >
> > There are probably some ways to fix this such as one below that I
> > tried (in mpparse.c):
> >
> > if (m->mpc_cpuflag & CPU_BOOTPROCESSOR) {
> > Dprintk(" Bootup CPU\n");
> > boot_cpu_physical_apicid = m->mpc_apicid;
> > + cpu_2_logical_apicid[num_processors] =
> m->mpc_apicid;
> > }
> > it worked, but looks more like a kludge of course. I think IO-APIC
> > setup has to happen after processors were brought online and so is
> > check_timer(), if timer is connected through the IO-APIC.
>
> The first cpu is brought online much earlier than the rest.
> So we just need to setup a table for boot cpu earlier. From
> the looks of it mach-es700 won't work if you compile a
> uniprocessor kernel for it right now.
Yea, I didn't even try this - but I think it will produce the same
result with regard to timer IOAPIC rte.
> We need to do this a little later than in mptable but this
> should be a fairly simple one or two line change.
Yes, it is maybe something like running map_cpu_to_logical_apicid() from
APIC_init() just before the setup_IO_APIC().
Thanks,
--Natalie
> If people keep breaking the subarchitectures by accident we
> might even inspire someone to make a comprehensible sub
> architecture implentation on x86 one of these days.
>
>
> Eric
>
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