Re: [PATCH 3/8] SFI: core support

From: Feng Tang
Date: Tue Jun 23 2009 - 05:16:28 EST


On Tue, 23 Jun 2009 17:03:47 +0800
Ingo Molnar <mingo@xxxxxxx> wrote:

>
> * Feng Tang <feng.tang@xxxxxxxxx> wrote:
>
> > On Tue, 23 Jun 2009 15:56:43 +0800
> > Ingo Molnar <mingo@xxxxxxx> wrote:
> >
> >
> > > >
> > > > +#ifdef CONFIG_X86_LOCAL_APIC
> > > > +static u64 sfi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
> > > > +#endif
> > >
> > > if SFI adds a 'depends on X86_LOCAL_APIC' the ugly #ifdef can be
> > > dropped.
> >
> > When Len designed the SFI spec, he considered the possibility of
> > being used by multiple archs, so we chose not to add a x86
> > dependency, though adding these
> > #ifdef does make code ugly :P
>
> But the file i commented on is arch/x86/kernel/sfi.c, not
> drivers/sfi/.

Now got your point, then we can think about adding a SFI_X86 Kconfig
option specifically for x86 platform, which has dependency over the
LAPIC/IO_APIC

Thanks,
Feng

>
> Those #ifdefs arent _that_ bad (and are used elsewhere in x86 code
> too) - but generally some effort should be spent in new code on
> trying to eliminate them.
>
> > > In general, nice stuff - basically SFI is cleanly implemented
> > > ACPI tables without any of the run-code-in-acpi-tables
> > > complications, right?
> >
> > Thanks for the comments, I really got inspired :). The expectation
> > for SFI is to be able to run cleanly with CONFIG_ACPI=n, and it
> > works fine on some intel platform.
>
> Ok, cool!
>
> Ingo
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