From a05f0e5be4e81e4977d3f92aaf7688ee0cb7d5db Mon Sep 17 00:00:00 2001
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Date: Wed, 29 Jan 2020 19:21:21 +0530
Subject: [PATCH] powerpc/smp: Use nid as fallback for package_id

References: bsc#1165813 ltc#184091
Patch-mainline: v5.7-rc1
Git-commit: a05f0e5be4e81e4977d3f92aaf7688ee0cb7d5db

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 <srikar@linux.vnet.ibm.com>
[mpe: Use pkg_id instead of ppid, tweak change log and comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200129135121.24617-1-srikar@linux.vnet.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/topology.h |  6 ++++++
 arch/powerpc/kernel/smp.c           | 30 ++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 2f7e1ea5089e..e2e1ccd4a18d 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -134,7 +134,13 @@ static inline void shared_proc_topology_init(void) {}
 #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))
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ea6adbf6a221..f68cde82bdf3 100644
--- 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 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;
 
 	/*
@@ -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 (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);
 }
 
-- 
2.23.0