Re: [PATCH RFC v4 02/15] ACPI: processor: Register all CPUs from acpi_processor_get_info()

Jonathan Cameron
2024-04-10T12:43:22Z

> >
> > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> > > index 47de0f140ba6..13d052bf13f4 100644
> > > --- a/drivers/base/cpu.c
> > > +++ b/drivers/base/cpu.c
> > > @@ -553,7 +553,11 @@ static void __init cpu_dev_register_generic(void)
> > > {
> > > int i, ret;
> > >
> > > - if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
> > > + /*
> > > + * When ACPI is enabled, CPUs are registered via
> > > + * acpi_processor_get_info().
> > > + */
> > > + if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES) || !acpi_disabled)
> > > return;
> >
> > Honestly, this looks like a quick hack to me and it absolutely
> > requires an ACK from the x86 maintainers to go anywhere.
> Will address this separately.
>

So do people prefer this hack, or something along lines of the following?

static int __init cpu_dev_register_generic(void)
{
int i, ret = 0;

for_each_online_cpu(i) {
if (!get_cpu_device(i)) {
ret = arch_register_cpu(i);
if (ret)
pr_warn("register_cpu %d failed (%d)\n", i, ret);
}
}
//Probably just eat the error.
return 0;
}
subsys_initcall_sync(cpu_dev_register_generic);

Which may look familiar at it's effectively patch 3 from v3 which was dealing
with CPUs missing from DSDT (something we think doesn't happen).

It might be possible to elide the arch_register_cpu() in
make_present() but that will mean we use different flows in this patch set
for the hotplug and initially present cases which is a bit messy.

I've tested this lightly on arm64 and x86 ACPI + DT booting and it "seems" fine.

Jonathan

> >
> > >
> > > for_each_present_cpu(i) {
> > > --
>
>
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