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-rw-r--r--drivers/perf/arm-cmn.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 47e7c3206..899e4ed49 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -2178,6 +2178,17 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset)
dev_dbg(cmn->dev, "ignoring external node %llx\n", reg);
continue;
}
+ /*
+ * AmpereOneX erratum AC04_MESH_1 makes some XPs report a bogus
+ * child count larger than the number of valid child pointers.
+ * A child offset of 0 can only occur on CMN-600; otherwise it
+ * would imply the root node being its own grandchild, which
+ * we can safely dismiss in general.
+ */
+ if (reg == 0 && cmn->part != PART_CMN600) {
+ dev_dbg(cmn->dev, "bogus child pointer?\n");
+ continue;
+ }
arm_cmn_init_node_info(cmn, reg & CMN_CHILD_NODE_ADDR, dn);