Re: Switch APIC (+nmi, +oprofile) to driver model

From: Mikael Pettersson (
Date: Mon Feb 10 2003 - 14:05:59 EST

On Mon, 10 Feb 2003 12:01:09 +0100, Pavel Machek wrote:
>> Also, apic_phys is (or should be) APIC_DEFAULT_PHYS_BASE, so
>> you shouldn't need to make apic_phys global.
> /*
> * If no local APIC can be found then set up a fake all
> * zeroes page to simulate the local APIC and another
> * one for the IO-APIC.
> */
> if (!smp_found_config && detect_init_APIC()) {
> apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
> apic_phys = __pa(apic_phys);
> } else
> apic_phys = mp_lapic_addr;
> set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
>So it seems to me it really is variable.

The original code has the property that is
true if and only if detect_init_APIC() was called and succeeded,
which implies that apic_phys == mp_lapic_addr == APIC_DEFAULT_PHYS_BASE.
You can also see that apic_pm_resume() writes APIC_DEFAULT_PHYS_BASE
to MSR_IA32_APICBASE, which only makes sense in this situation.

You moved the = 1 assignment from detect_init_APIC(),
which is specific to UP_APIC, to setup_local_APIC(), which is called
also in the SMP case. Do you intend to do suspend and resume on SMP boxes
as well? If this is intensional, shouldn't device_apic be per-cpu?

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