diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 03be786..d2f463f 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -374,6 +374,12 @@
    can take the values 0 to 2, to align  with the ``FEATURE_DETECTION``
    mechanism. Default value is ``0``.
 
+-  ``ENABLE_FEAT_GCS``: Numeric value to set the bit SCR_EL3.GCSEn in EL3 to
+   allow use of Guarded Control Stack from EL2 as well as adding the GCS
+   registers to the EL2 context save/restore operations. This flag can take
+   the values 0 to 2, to align  with the ``FEATURE_DETECTION`` mechanism.
+   Default value is ``0``.
+
 -  ``ENABLE_LTO``: Boolean option to enable Link Time Optimization (LTO)
    support in GCC for TF-A. This option is currently only supported for
    AArch64. Default is 0.