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2Generic OS migration from Armv7-M to Armv8-M architecture
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4The purpose of this document is to list a set of requirements needed for
5migrating a generic OS kernel running on Armv7-M to the Armv8-M architecture.
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8List of requirements
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10- If the same OS codebase is used for both Secure and Non Secure builds, it is
11  suggested to put specific code targeted to the Non Secure build under a
12  compile time switch, e.g. ``#if (DOMAIN_NS == 1U)``. The OS build system in
13  this case needs to be amended accordingly to support this new switch.
14- If the OS implements stack limit checking, the ``PSPLIM`` register
15  needs to be initialized and properly handled during thread context switch
16  operations.
17- If the OS manipulates directly the Link Register, the default Link Register
18  value used in Handler mode transitions needs to be differentiated between
19  Secure and Non Secure builds, i.e. ``0xFD`` and ``0xBC``, respectively.
20- If the OS manages the non-secure client identification, please check the
21  :doc:`Non-secure Client Extension Integration Guide </integration_guide/non-secure_client_extension_integration_guide>`.
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25*Copyright (c) 2018-2021, Arm Limited. All rights reserved.*
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