4.2. Activity Monitors
FEAT_AMUv1 of the Armv8-A architecture introduces the Activity Monitors extension. This extension describes the architecture for the Activity Monitor Unit (AMU), an optional non-invasive component for monitoring core events through a set of 64-bit counters.
ENABLE_FEAT_AMU=1 build option is provided, Trusted Firmware-A
sets up the AMU prior to its exit from EL3, and will save and restore
architected AMU counters as necessary upon suspend and resume.
4.2.1. Auxiliary counters
FEAT_AMUv1 describes a set of implementation-defined auxiliary counters (also
known as group 1 counters), controlled by the
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
A platform implementation of the
plat_amu_topologyfunction (the default).
See Activity Monitor Unit (AMU) Bindings for documentation on the FCONF device tree bindings.
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