GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
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+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.
+
+When the ``ENABLE_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.
+
+.. _Activity Monitor Auxiliary Counters:
+
+Auxiliary counters
+------------------
+
+FEAT_AMUv1 describes a set of implementation-defined auxiliary counters (also
+known as group 1 counters), controlled by the ``ENABLE_AMU_AUXILIARY_COUNTERS``
+build option.
+
+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 ``ENABLE_AMU_FCONF`` build option.
+- A platform implementation of the ``plat_amu_topology`` function (the default).
+
+See :ref:`Activity Monitor Unit (AMU) Bindings` for documentation on the |FCONF|
+device tree bindings.
+
+--------------
+
+*Copyright (c) 2021, Arm Limited. All rights reserved.*