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SubjectRe: [PATCH 00/10] x86, xsave: some code cleanups and reworks
On Wed, Jul 21, 2010 at 12:07:29AM +0400, Cyrill Gorcunov wrote:
...
> >
> > But first question is, is it always !smp_processor_id()? At least
> > current implementation indicates this:
> >
>
> I guess so, since it's assigned from boot_cpu_id iirc
>

well, not true, this id is being set in setup_per_cpu_areas()
note the snippet

if (cpu == boot_cpu_id)
switch_to_new_gdt(cpu);

but cycle of assignment is done over all possible cpus so
smp_processor_id will be = 0 for BP but definitely it's
confusing and better to check for BP via explicit cpu == boot_cpu_id
I think. Though I might be missing something.

> > void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
> > {
> > BUG_ON(c == &boot_cpu_data);
> > ...
> >
> > with:
> >
> > #define boot_cpu_data cpu_data[0]
> >
> > ... which is valid for 32 and 64 bit.
> >

-- Cyrill


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