* Gautham R Shenoy <e...@linux.vnet.ibm.com> [2020-01-30 16:27:47]:
> On Wed, Jan 29, 2020 at 07:21:21PM +0530, Srikar Dronamraju wrote:
>
> [..snip..]
>
> > --- a/arch/powerpc/kernel/smp.c
> > +++ b/arch/powerpc/kernel/smp.c
> > @@ -1185,10 +1185,34 @@ static inline void add_cpu_to_smallcore_masks(int
> > cpu)
> > }
> > }
> >
> > +int get_physical_package_id(int cpu)
> > +{
> > + int ppid = cpu_to_chip_id(cpu);
> > +
> > +#ifdef CONFIG_PPC_SPLPAR
> > + /*
> > + * If the platform is PowerNV or Guest on KVM, ibm,chip-id is
> > + * defined. Hence we would return the chip-id as the
> > + * get_physical_package_id.
> > + */
> > + if (ppid == -1 && firmware_has_feature(FW_FEATURE_LPAR)) {
> > + struct device_node *np = of_get_cpu_node(cpu, NULL);
> > +
> > + if (np) {
> > + ppid = of_node_to_nid(np);
> > + of_node_put(np);
> > + }
> > + }
> > +#endif /* CONFIG_PPC_SPLPAR */
> > +
> > + return ppid;
> > +}
> > static void add_cpu_to_masks(int cpu)
> > {
> > int first_thread = cpu_first_thread_sibling(cpu);
> > - int chipid = cpu_to_chip_id(cpu);
> > + int ppid = get_physical_package_id(cpu);
> > int i;
> >
> > /*
> > @@ -1217,11 +1241,11 @@ static void add_cpu_to_masks(int cpu)
> > for_each_cpu(i, cpu_l2_cache_mask(cpu))
> > set_cpus_related(cpu, i, cpu_core_mask);
> >
> > - if (chipid == -1)
> > + if (ppid == -1)
> > return;
>
> Can get_physical_package_id() return -1 ?
>
Yes, it can return -1,
1. A System doesnt have CONFIG_PPC_SPLPAR: cpu_to_chip_id() might return -1.
2. A System with CONFIG_PPC_SPLPAR: Still can return -1 for following cases.
a. Not having firmware feature FW_FEATURE_LPAR
b. If for some reason, of_get_cpu_node property is not present.
> >
> > for_each_cpu(i, cpu_online_mask)
> > - if (cpu_to_chip_id(i) == chipid)
> > + if (get_physical_package_id(i) == ppid)
> > set_cpus_related(cpu, i, cpu_core_mask);
> > }
--
Thanks and Regards
Srikar Dronamraju
