diff --git a/docs/components/activity-monitors.rst b/docs/components/activity-monitors.rst
index 57d81f8..ee280e2 100644
--- a/docs/components/activity-monitors.rst
+++ b/docs/components/activity-monitors.rst
@@ -10,6 +10,23 @@
 the |AMU| prior to its exit from EL3, and will save and restore architected
 |AMU| counters as necessary upon suspend and resume.
 
+Auxiliary counters
+------------------
+
+FEAT_AMUv1 describes a set of implementation-defined auxiliary counters (also
+known as group 1 counters), controlled by the ``ENABLE_AMU_AUXILIARY_COUNTERS``
+build option.
+
+As a security precaution, Trusted Firmware-A does not enable these by default.
+Instead, platforms may configure their auxiliary counters through one of two
+possible mechanisms:
+
+- |FCONF|, controlled by the ``ENABLE_AMU_FCONF`` build option.
+- A platform implementation of the ``plat_amu_topology`` function (the default).
+
+See :ref:`Activity Monitor Unit (AMU) Bindings` for documentation on the |FCONF|
+device tree bindings.
+
 --------------
 
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