From 302039466f6a3b9421ecb9a6a2c528801dc24a86 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Tue, 9 Nov 2021 16:49:00 +1000
Subject: [PATCH] powerpc/pseries: Fix numa FORM2 parsing fallback code

References: jsc#PED-551
Patch-mainline: v5.16-rc2
Git-commit: 302039466f6a3b9421ecb9a6a2c528801dc24a86

In case the FORM2 distance table from firmware is not the expected size,
there is fallback code that just populates the lookup table as local vs
remote.

However it then continues on to use the distance table. Fix.

Fixes: 1c6b5a7e7405 ("powerpc/pseries: Add support for FORM2 associativity")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211109064900.2041386-2-npiggin@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/mm/numa.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 53e990140916..59d3cfcd7887 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -407,30 +407,26 @@ static void initialize_form2_numa_distance_lookup_table(void)
 
 	if (form2_distances_length != max_numa_index * max_numa_index) {
 		WARN(1, "Wrong NUMA distance information\n");
-		/* consider everybody else just remote. */
-		for (i = 0;  i < max_numa_index; i++) {
-			for (j = 0; j < max_numa_index; j++) {
-				int nodeA = numa_id_index_table[i];
-				int nodeB = numa_id_index_table[j];
-
-				if (nodeA == nodeB)
-					numa_distance_table[nodeA][nodeB] = LOCAL_DISTANCE;
-				else
-					numa_distance_table[nodeA][nodeB] = REMOTE_DISTANCE;
-			}
-		}
+		form2_distances = NULL; // don't use it
 	}
-
 	distance_index = 0;
 	for (i = 0;  i < max_numa_index; i++) {
 		for (j = 0; j < max_numa_index; j++) {
 			int nodeA = numa_id_index_table[i];
 			int nodeB = numa_id_index_table[j];
-
-			numa_distance_table[nodeA][nodeB] = form2_distances[distance_index++];
-			pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, numa_distance_table[nodeA][nodeB]);
+			int dist;
+
+			if (form2_distances)
+				dist = form2_distances[distance_index++];
+			else if (nodeA == nodeB)
+				dist = LOCAL_DISTANCE;
+			else
+				dist = REMOTE_DISTANCE;
+			numa_distance_table[nodeA][nodeB] = dist;
+			pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, dist);
 		}
 	}
+
 	of_node_put(root);
 }
 
-- 
2.35.3