Messages in this thread | | | Date | Tue, 11 Feb 2003 12:39:02 +0100 | From | Pavel Machek <> | Subject | Re: Switch APIC (+nmi, +oprofile) to driver model |
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Hi!
> >> Also, apic_phys is (or should be) APIC_DEFAULT_PHYS_BASE, so > >> you shouldn't need to make apic_phys global. > > > >Really? > > > > /* > > * 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 apic_pm_state.active 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.
Okay, I guess I do not rely on so complicated invariants...
> You moved the apic_pm_state.active = 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?
Eventually, I do want suspend working on SMP machines, but that's still quite a long way to go: plan is to hot-unplug all but boot CPUs, then do suspend, then hot-plug them back.
Pavel
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