fix(ras): restrict ENABLE_FEAT_RAS to have only two states
As part of migrating RAS extension to feature detection mechanism, the
macro ENABLE_FEAT_RAS was allowed to have dynamic detection (FEAT_STATE
2). Considering this feature does impact execution of EL3 and we need
to know at compile time about the presence of this feature. Do not use
dynamic detection part of feature detection mechanism.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I23858f641f81fbd81b6b17504eb4a2cc65c1a752
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 347cf20..51c5c78 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -813,8 +813,10 @@
- ``ENABLE_FEAT_RAS``: Numeric value to enable Armv8.2 RAS features. RAS features
are an optional extension for pre-Armv8.2 CPUs, but are mandatory for Armv8.2
- or later CPUs. This flag can take the values 0 to 2, to align with the
- ``FEATURE_DETECTION`` mechanism.
+ or later CPUs. This flag can take the values 0 or 1. The default value is 0.
+ NOTE: This flag enables use of IESB capability to reduce entry latency into
+ EL3 even when RAS error handling is not performed on the platform. Hence this
+ flag is recommended to be turned on Armv8.2 and later CPUs.
- ``RAS_FFH_SUPPORT``: Support to enable Firmware first handling of RAS errors
originating from NS world. When ``RAS_FFH_SUPPORT`` is set to ``1``,