powerpc/smp: Use nid as fallback for package_id

package_id is to match cores that are part of the same chip. On
PowerNV machines, package_id defaults to chip_id. However ibm,chip_id
property is not present in device-tree of PowerVM LPARs. Hence lscpu
output shows one core per socket and multiple cores.

To overcome this, use nid as the package_id on PowerVM LPARs.

Before the patch:

Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Thread(s) per core: 8
Core(s) per socket: 1 <----------------------
Socket(s): 16 <----------------------
NUMA node(s): 2
Model: 2.2 (pvr 004e 0202)
Model name: POWER9 (architected), altivec supported
Hypervisor vendor: pHyp
Virtualization type: para
L1d cache: 32K
L1i cache: 32K
L2 cache: 512K
L3 cache: 10240K
NUMA node0 CPU(s): 0-63
NUMA node1 CPU(s): 64-127
#
# cat /sys/devices/system/cpu/cpu0/topology/physical_package_id
-1

After the patch:

Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Thread(s) per core: 8 <---------------------
Core(s) per socket: 8 <---------------------
Socket(s): 2
NUMA node(s): 2
Model: 2.2 (pvr 004e 0202)
Model name: POWER9 (architected), altivec supported
Hypervisor vendor: pHyp
Virtualization type: para
L1d cache: 32K
L1i cache: 32K
L2 cache: 512K
L3 cache: 10240K
NUMA node0 CPU(s): 0-63
NUMA node1 CPU(s): 64-127
#
# cat /sys/devices/system/cpu/cpu0/topology/physical_package_id
0

Now lscpu output is more in line with the system configuration.

Signed-off-by: Srikar Dronamraju <[e-mail]>
[mpe: Use pkg_id instead of ppid, tweak change log and comment]
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/include/asm/topology.h

···
 #ifdef CONFIG_PPC64
 #include <asm/smp.h>
 
+#ifdef CONFIG_PPC_SPLPAR
+int get_physical_package_id(int cpu);
+#define topology_physical_package_id(cpu)	(get_physical_package_id(cpu))
+#else
 #define topology_physical_package_id(cpu)	(cpu_to_chip_id(cpu))
+#endif
+
 #define topology_sibling_cpumask(cpu)	(per_cpu(cpu_sibling_map, cpu))
 #define topology_core_cpumask(cpu)	(per_cpu(cpu_core_map, cpu))
 #define topology_core_id(cpu)		(cpu_to_core_id(cpu))

arch/powerpc/kernel/smp.c

···
 	}
 }
 
+int get_physical_package_id(int cpu)
+{
+	int pkg_id = 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 result of
+	 * get_physical_package_id.
+	 */
+	if (pkg_id == -1 && firmware_has_feature(FW_FEATURE_LPAR)) {
+		struct device_node *np = of_get_cpu_node(cpu, NULL);
+
+		if (np) {
+			pkg_id = of_node_to_nid(np);
+			of_node_put(np);
+		}
+	}
+#endif /* CONFIG_PPC_SPLPAR */
+
+	return pkg_id;
+}
+EXPORT_SYMBOL_GPL(get_physical_package_id);
+
 static void add_cpu_to_masks(int cpu)
 {
 	int first_thread = cpu_first_thread_sibling(cpu);
-	int chipid = cpu_to_chip_id(cpu);
+	int pkg_id = get_physical_package_id(cpu);
 	int i;
 
 	/*
···
 	for_each_cpu(i, cpu_l2_cache_mask(cpu))
 		set_cpus_related(cpu, i, cpu_core_mask);
 
-	if (chipid == -1)
+	if (pkg_id == -1)
 		return;
 
 	for_each_cpu(i, cpu_online_mask)
-		if (cpu_to_chip_id(i) == chipid)
+		if (get_physical_package_id(i) == pkg_id)
 			set_cpus_related(cpu, i, cpu_core_mask);
 }