1Vendor Specific EL3 Monitor Service Calls 2========================================= 3 4This document enumerates and describes the Vendor Specific EL3 Monitor Service 5Calls. 6 7These are Service Calls defined by the vendor of the EL3 Monitor. 8They are accessed via ``SMC`` ("SMC calls") instruction executed from Exception 9Levels below EL3. SMC calls for Vendor Specific EL3 Monitor Services: 10 11- Follow `SMC Calling Convention`_; 12- Use SMC function IDs that fall in the vendor-specific EL3 range, which are 13 14+---------------------------+--------------------------------------------------+ 15| SMC Function Identifier | Service Type | 16+===========================+==================================================+ 17| 0x87000000 - 0x8700FFFF | SMC32: Vendor Specific EL3 Monitor Service Calls | 18+---------------------------+--------------------------------------------------+ 19| 0xC7000000 - 0xC700FFFF | SMC64: Vendor Specific EL3 Monitor Service Calls | 20+---------------------------+--------------------------------------------------+ 21 22Vendor-specific EL3 monitor services are as follows: 23 24+-----------------------------------+-----------------------+---------------------------------------------+ 25| SMC Function Identifier | Service Type | FID's Usage | 26+===================================+=======================+=============================================+ 27| 0x87000010 - 0x8700001F (SMC32) | DebugFS Interface | | 0 - 11 are in use. | 28+-----------------------------------+ | | 12 - 15 are reserved for future expansion.| 29| 0xC7000010 - 0xC700001F (SMC64) | | | 30+-----------------------------------+-----------------------+---------------------------------------------+ 31| 0x87000020 - 0x8700002F (SMC32) | Performance | | 0,1 is in use. | 32+-----------------------------------+ Measurement Framework | | 2 - 15 are reserved for future expansion. | 33| 0xC7000020 - 0xC700002F (SMC64) | (PMF) | | 34+-----------------------------------+-----------------------+---------------------------------------------+ 35| 0x87000030 - 0x8700003F (SMC32) | ACS (Architecture | | 0 in use. | 36+-----------------------------------+ Compliance Suite) SMC | | 1 - 15 are reserved for future expansion. | 37| 0xC7000030 - 0xC700003F (SMC64) | handler | | 38+-----------------------------------+-----------------------+---------------------------------------------+ 39| 0x87000040 - 0x8700FFFF (SMC32) | Reserved | | reserved for future expansion | 40+-----------------------------------+ | | 41| 0xC7000040 - 0xC700FFFF (SMC64) | | | 42+-----------------------------------+-----------------------+---------------------------------------------+ 43 44Source definitions for vendor-specific EL3 Monitor Service Calls used by TF-A are located in 45the ``ven_el3_svc.h`` header file. 46 47+----------------------------+----------------------------+--------------------------------+ 48| VEN_EL3_SVC_VERSION_MAJOR | VEN_EL3_SVC_VERSION_MINOR | Changes | 49+============================+============================+================================+ 50| 1 | 0 | Added Debugfs and PMF services.| 51+----------------------------+----------------------------+--------------------------------+ 52| 1 | 1 | Added ACS SMC handler services.| 53+----------------------------+----------------------------+--------------------------------+ 54 55*Table 1: Showing different versions of Vendor-specific service and changes done with each version* 56 57Each sub service will have its own version, one FID allocated for sub service version. 58 59Some ground rules when one should update top level version. 60 - VEN_EL3_SVC_VERSION_MAJOR is incremented when any of the sub service version discovery 61 FID changes or the FID that was allocated for discovery changes. So any breaking subfeature 62 discovery changes will lead to major version update. 63 - VEN_EL3_SVC_VERSION_MINOR is incremented when we add a new FID or a new sub service. 64 For example adding an new monitor service at 0x30, Debugfs starts at 0x10 and PMF 65 starts at 0x20 next one will start at 0x30, this will need a update to minor version. 66 67Performance Measurement Framework (PMF) 68--------------------------------------- 69 70The :ref:`Performance Measurement Framework <firmware_design_pmf>` 71allows callers to retrieve timestamps captured at various paths in TF-A 72execution. 73 74DebugFS interface 75----------------- 76 77The optional DebugFS interface is accessed through Vendor specific EL3 service. Refer 78to :ref:`DebugFS interface` documentation for further details and usage. 79 80Architecture Compliance Suite (ACS) SMC handler 81----------------------------------------------- 82 83The Architecture Compliance Suite (ACS) SMC handler allows callers to branch 84to their ACS EL3 code based on their respective use-cases. 85For more details on System ACS, `System ACS`_. 86 87-------------- 88 89*Copyright (c) 2024-2025, Arm Limited and Contributors. All rights reserved.* 90 91.. _System ACS: https://developer.arm.com/Architectures/Architectural%20Compliance%20Suite 92.. _SMC Calling Convention: https://developer.arm.com/docs/den0028/latest 93