| Chris Kay | cda8921 | 2021-08-17 16:24:57 +0100 | [diff] [blame] | 1 | Activity Monitors |
| 2 | ================= |
| 3 | |
| 4 | FEAT_AMUv1 of the Armv8-A architecture introduces the Activity Monitors |
| 5 | extension. This extension describes the architecture for the Activity Monitor |
| 6 | Unit (|AMU|), an optional non-invasive component for monitoring core events |
| 7 | through a set of 64-bit counters. |
| 8 | |
| Andre Przywara | 0b7f1b0 | 2023-03-21 13:53:19 +0000 | [diff] [blame] | 9 | When the ``ENABLE_FEAT_AMU=1`` build option is provided, Trusted Firmware-A |
| 10 | sets up the |AMU| prior to its exit from EL3, and will save and restore |
| 11 | architected |AMU| counters as necessary upon suspend and resume. |
| Chris Kay | cda8921 | 2021-08-17 16:24:57 +0100 | [diff] [blame] | 12 | |
| Chris Kay | 03be39d | 2021-05-05 13:38:30 +0100 | [diff] [blame] | 13 | .. _Activity Monitor Auxiliary Counters: |
| 14 | |
| Chris Kay | f11909f | 2021-08-19 11:21:52 +0100 | [diff] [blame] | 15 | Auxiliary counters |
| 16 | ------------------ |
| 17 | |
| 18 | FEAT_AMUv1 describes a set of implementation-defined auxiliary counters (also |
| 19 | known as group 1 counters), controlled by the ``ENABLE_AMU_AUXILIARY_COUNTERS`` |
| 20 | build option. |
| 21 | |
| 22 | As a security precaution, Trusted Firmware-A does not enable these by default. |
| Boyan Karatotev | b295347 | 2024-11-06 14:55:35 +0000 | [diff] [blame^] | 23 | Instead, platforms must configure their auxiliary counters through the |
| 24 | ``plat_amu_aux_enables`` platform hook. |
| Chris Kay | f11909f | 2021-08-19 11:21:52 +0100 | [diff] [blame] | 25 | |
| Chris Kay | cda8921 | 2021-08-17 16:24:57 +0100 | [diff] [blame] | 26 | -------------- |
| 27 | |
| Boyan Karatotev | b295347 | 2024-11-06 14:55:35 +0000 | [diff] [blame^] | 28 | *Copyright (c) 2021-2025, Arm Limited. All rights reserved.* |