[PPC64] Fix NUMA on POWER8

On some POWER8 machines, 'ibm,associativity' property may have 6
cells, which would overflow the 5 cells buffer being used.
There was also an issue with the "check if node is root" part,
that have been fixed too.

Reviewed by:	jhibbits
Differential Revision:	https://reviews.freebsd.org/D23414

1 files changed, 13 insertions, 10 deletions

diff --git a/sys/powerpc/powernv/platform_powernv.c b/sys/powerpc/powernv/platform_powernv.c
index f6f39da253ec..15e604e52fbb 100644
--- a/sys/powerpc/powernv/platform_powernv.c
+++ b/sys/powerpc/powernv/platform_powernv.c
@@ -517,17 +517,20 @@ powernv_node_numa_domain(platform_t platform, phandle_t node)
 	cell_t associativity[5];
 	int i, res;
 
-	res = OF_getproplen(node, "ibm,associativity");
+	res = OF_getencprop(node, "ibm,associativity",
+		associativity, sizeof(associativity));
 
-	/* If already at the root, use default domain. */
-	if (res == 0)
-		return (0);
-	else if (res < 0)
-		/* If this node doesn't have associativity, check its parent. */
-		return (powernv_node_numa_domain(platform, OF_parent(node)));
-
-	OF_getencprop(node, "ibm,associativity",
-		associativity, res);
+	/*
+	 * If this node doesn't have associativity, or if there are not
+	 * enough elements in it, check its parent.
+	 */
+	if (res < (int)(sizeof(cell_t) * (platform_associativity + 1))) {
+		node = OF_parent(node);
+		/* If already at the root, use default domain. */
+		if (node == 0)
+			return (0);
+		return (powernv_node_numa_domain(platform, node));
+	}
 
 	for (i = 0; i < numa_max_domain; i++) {
 		if (numa_domains[i] == associativity[platform_associativity])