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Change-Id: I90f1bcaa8bec133d3be81785aea11948208ca0a5 Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
30 lines
1.1 KiB
ReStructuredText
30 lines
1.1 KiB
ReStructuredText
Activity Monitors
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=================
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FEAT_AMUv1 of the Armv8-A architecture introduces the Activity Monitors
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extension. This extension describes the architecture for the Activity Monitor
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Unit (|AMU|), an optional non-invasive component for monitoring core events
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through a set of 64-bit counters.
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When the ``ENABLE_FEAT_AMU=1`` build option is provided, Trusted Firmware-A
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sets up the |AMU| prior to its exit from EL3, and will save and restore
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architected |AMU| counters as necessary upon suspend and resume.
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.. _Activity Monitor Auxiliary Counters:
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Auxiliary counters
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------------------
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FEAT_AMUv1 describes a set of implementation-defined auxiliary counters (also
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known as group 1 counters), controlled by the ``ENABLE_AMU_AUXILIARY_COUNTERS``
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build option.
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As a security precaution, Trusted Firmware-A does not enable these by default.
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Instead, platforms must configure their auxiliary counters through the
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``plat_amu_aux_enables`` platform hook. This is a per-core array indexed with
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``plat_my_core_pos()``. A core's value will be written verbatim into
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``AMCNTENSET1_EL0``.
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--------------
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*Copyright (c) 2021-2025, Arm Limited. All rights reserved.*
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