Re: [PATCH v2 2/3] powerpc/numa: Allow cpu_to_coregroup_id without PPC_SPLPAR

* Ritesh Harjani [off-list ref] [2026-07-10 09:34:55]:

Srikar Dronamraju [off-list ref] writes:

quoted

Make cpu_to_coregroup_id() available outside PPC_SPLPAR so it can be
used by platforms that do not rely on the SPLPAR-specific VPHN path.

Keep the existing fallback behavior by returning the core ID when
coregroup information is unavailable.

Looks like this mainly brings the cpu_to_coregroup_id() outside of
CONFIG_PPC_SPLPAR gate. 

Yes, thats the intent of the patch

quoted

Signed-off-by: Srikar Dronamraju <redacted>
---
Changelog from v1:
- Handle comments from Christophe Leroy; Remove extern key word in
  declaration

 arch/powerpc/include/asm/topology.h | 15 +++++++--------
 arch/powerpc/mm/numa.c              | 22 ++++++++++++++++------
 2 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 66ed5fe1b718..385715f1ad56 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h

@@ -71,6 +71,7 @@ extern void map_cpu_to_node(int cpu, int node);
 extern void unmap_cpu_from_node(unsigned long cpu);
 #endif /* CONFIG_HOTPLUG_CPU */
 
+int cpu_to_coregroup_id(int cpu);
 #else
 
 static inline int early_cpu_to_node(int cpu) { return 0; }

@@ -107,14 +108,6 @@ static inline void map_cpu_to_node(int cpu, int node) {}
 static inline void unmap_cpu_from_node(unsigned long cpu) {}
 #endif /* CONFIG_HOTPLUG_CPU */
 #endif /* CONFIG_SMP */
-
-#endif /* CONFIG_NUMA */
-
-#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
-void find_and_update_cpu_nid(int cpu);
-extern int cpu_to_coregroup_id(int cpu);
-#else
-static inline void find_and_update_cpu_nid(int cpu) {}
 static inline int cpu_to_coregroup_id(int cpu)
 {
 #ifdef CONFIG_SMP

@@ -124,6 +117,12 @@ static inline int cpu_to_coregroup_id(int cpu)
 #endif
 }
 
+#endif /* CONFIG_NUMA */
+
+#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
+void find_and_update_cpu_nid(int cpu);
+#else
+static inline void find_and_update_cpu_nid(int cpu) {}
 #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
 
 #include <asm-generic/topology.h>

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index c44a80d8fc11..9aa71eb7e96b 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c

@@ -1428,6 +1428,21 @@ void find_and_update_cpu_nid(int cpu)
 	pr_debug("%s:%d cpu %d nid %d\n", __func__, __LINE__, cpu, new_nid);
 }
 
+static int topology_update_init(void)
+{
+	topology_inited = 1;
+	return 0;
+}
+device_initcall(topology_update_init);
+
+#else
+static long vphn_get_associativity(unsigned long cpu,
+					__be32 *associativity)
+{
+	return -1;
+}
+#endif /* CONFIG_PPC_SPLPAR */
+
 int cpu_to_coregroup_id(int cpu)
 {
 	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};

@@ -1453,10 +1468,5 @@ int cpu_to_coregroup_id(int cpu)
 	return cpu_to_core_id(cpu);
 }
 
-static int topology_update_init(void)
-{
-	topology_inited = 1;
-	return 0;
+	return coregroup_id;
 }

These above two lines seems to be out of any function scope. So applying
only patch-1 & patch-2 will give a compile error. This needs fixing.

Yes, will fix this

-ritesh

quoted

-device_initcall(topology_update_init);
-#endif /* CONFIG_PPC_SPLPAR */
-- 
2.43.0

-- 
Thanks and Regards
Srikar Dronamraju