Merge "build(amu): restrict counters (RAZ)" into integration

docs/getting_started/build-options.rst

@@ -23,8 +23,9 @@ Common build options
    is expected to contain a makefile called ``<aarch32_sp-value>.mk``.
 
 -  ``AMU_RESTRICT_COUNTERS``: Register reads to the group 1 counters will return
-   zero at all but the highest implemented exception level.  Reads from the
-   memory mapped view are unaffected by this control.
+   zero at all but the highest implemented exception level. External
+   memory-mapped debug accesses are unaffected by this control.
+   The default value is 1 for all platforms.
 
 -  ``ARCH`` : Choose the target build architecture for TF-A. It can take either
    ``aarch64`` or ``aarch32`` as values. By default, it is defined to

make_helpers/arch_features.mk

@@ -280,7 +280,7 @@ endif
 ENABLE_FEAT_AMU				?=	0
 ENABLE_AMU_AUXILIARY_COUNTERS		?=	0
 ENABLE_AMU_FCONF			?=	0
-AMU_RESTRICT_COUNTERS			?=	0
+AMU_RESTRICT_COUNTERS			?=	1
 
 # Build option to enable MPAM for lower ELs.
 # Enabling it by default