diff --git a/docs/configuration/build_configuration.rst b/docs/configuration/build_configuration.rst
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+.. _tfm_cmake_configuration:
+
+###################
+Build configuration
+###################
+
+All configuration options are provided by cmake variables, and their default
+values, with docstrings, can be found in ``config/config_base.cmake``.
+
+Configuration is provided in multiple stages. Each stage will not override any
+config that has already been set at any of the prior stages.
+
+   1. Command-line variable settings are applied.
+   2. If the ``TFM_EXTRA_CONFIG_PATH`` variable has been set, that file is
+      loaded.
+   3. If TEST_PSA_TEST is set, then PSA API test related config is applied from
+      ``config/tests/config_test_psa_api.cmake``.
+   4. If it exists, CMAKE_BUILD_TYPE specific config is applied from
+      ``config/build_type/<build_type>.cmake``.
+   5. Target specific config from ``platform/ext/target/<target_platform>/config.cmake``
+      is applied.
+   6. If CRYPTO_HW_ACCELERATOR is set, then a config specific to the
+      accelerator type is applied if it exists.
+   7. If it exists, TFM Profile specific config is applied from
+      ``config/profile/<tfm_profile>.cmake``.
+   8. ``config/config_default.cmake`` is loaded.
+   9. If ``TEST_S`` or ``TEST_NS`` or other single test suite config like
+      ``TEST_NS_ATTESTATION`` (see :ref:`test_configuration`) is set, then
+      config from ``${TFM_TEST_REPO_PATH}/test/config/set_config.cmake`` and
+      ``${TFM_TEST_REPO_PATH}/test/config/default_ns_test_config.cmake`` or
+      ``${TFM_TEST_REPO_PATH}/test/config/default_s_test_config.cmake`` or
+      ``${TFM_TEST_REPO_PATH}/test/config/default_test_config.cmake`` is
+      applied.
+
+.. Warning::
+    This means that command-line settings are not applied when they conflict
+    with required platform settings. If it is required to override platform
+    settings (this is not usually a good idea) then TFM_EXTRA_CONFIG_PATH should be
+    used.