CONFIG_NULL_POINTER_EXCEPTION_DETECTION_MPU¶
Use MPU for null pointer exception detection
Type: bool
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.
Direct dependencies¶
!TRUSTED_EXECUTION_NONSECURE && ARM_MPU && <choice NULL_POINTER_EXCEPTION_DETECTION: Enable and use null-pointer exception>
(Includes any dependencies from ifs and menus.)
Symbols selected by this symbol¶
Kconfig definition¶
At arch/arm/core/aarch32/cortex_m/Kconfig:384
Included via Kconfig:8 → Kconfig.zephyr:39 → arch/Kconfig:12 → arch/arm/Kconfig:57 → arch/arm/core/aarch32/Kconfig:294
Menu path: (Top) → ARM Options → Enable and use null-pointer exception
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.)