:orphan:

.. title:: CONFIG_NULL_POINTER_EXCEPTION_DETECTION_MPU

.. kconfig:: CONFIG_NULL_POINTER_EXCEPTION_DETECTION_MPU

CONFIG_NULL_POINTER_EXCEPTION_DETECTION_MPU
###########################################

*Use MPU for null pointer exception detection*

Type: ``bool``

Help
====

.. code-block:: none

    Null pointer dereference detection implemented
    using MPU functionality.
    Notes:
    - Mutually exclusive to the DWT-based solution
    - Not enabled for Non-Secure FW images, where
    null-pointer dereferencing is likely caught as
    a SecureFault.
    - Requires MPU functionality to be present and
    enabled. The implementation consumes 1 MPU region.
    - In ARMv8-M, explicit null-pointer dereference
    detection with MPU requires, additionally, that
    the area: [0x0,
    CORTEX_M_NULL_POINTER_EXCEPTION_PAGE_SIZE)
    is not unmapped (covered by an MPU region already).
    If it is unmapped null-pointer dereferencing may
    still be idirectly detected (e.g. via a precise
    Bus access fault), but this is not guaranteed. A
    build-time message warns the user of this scenario.

Direct dependencies
===================

!\ :kconfig:`TRUSTED_EXECUTION_NONSECURE <CONFIG_TRUSTED_EXECUTION_NONSECURE>` && \ :kconfig:`ARM_MPU <CONFIG_ARM_MPU>` && \ :ref:`<choice NULL_POINTER_EXCEPTION_DETECTION: Enable and use null-pointer exception> <choice_17>`

*(Includes any dependencies from ifs and menus.)*

Symbols selected by this symbol
===============================

- \ :kconfig:`CORTEX_M_NULL_POINTER_EXCEPTION <CONFIG_CORTEX_M_NULL_POINTER_EXCEPTION>`

Kconfig definition
==================



At ``<Zephyr Architecture>/arm/core/aarch32/cortex_m/Kconfig:384``

Included via ``Kconfig:8`` → ``Kconfig.zephyr:39`` → ``<Zephyr Architecture>/Kconfig:12`` → ``<Zephyr Architecture>/arm/Kconfig:57`` → ``<Zephyr Architecture>/arm/core/aarch32/Kconfig:294``

Menu path: (Top) → ARM Options → Enable and use null-pointer exception

.. code-block:: kconfig

    config NULL_POINTER_EXCEPTION_DETECTION_MPU
    	bool "Use MPU for null pointer exception detection"
    	select CORTEX_M_NULL_POINTER_EXCEPTION
    	depends on !TRUSTED_EXECUTION_NONSECURE && ARM_MPU && <choice NULL_POINTER_EXCEPTION_DETECTION>
    	help
    	  Null pointer dereference detection implemented
    	  using MPU functionality.
    	  Notes:
    	  - Mutually exclusive to the DWT-based solution
    	  - Not enabled for Non-Secure FW images, where
    	  null-pointer dereferencing is likely caught as
    	  a SecureFault.
    	  - Requires MPU functionality to be present and
    	  enabled. The implementation consumes 1 MPU region.
    	  - In ARMv8-M, explicit null-pointer dereference
    	  detection with MPU requires, additionally, that
    	  the area: [0x0,
    	  CORTEX_M_NULL_POINTER_EXCEPTION_PAGE_SIZE)
    	  is not unmapped (covered by an MPU region already).
    	  If it is unmapped null-pointer dereferencing may
    	  still be idirectly detected (e.g. via a precise
    	  Bus access fault), but this is not guaranteed. A
    	  build-time message warns the user of this scenario.

*(The 'depends on' condition includes propagated dependencies from ifs and menus.)*