When NuttX is booted from a foreign (non NuttX)
bootloader. There as a possibility that the
bootloader configured the MPU, in an
incompatible way for the NuttX memory usage.
The option to reset the MPU before it is initialized
may not succeed if the bss and data initialization
code violated the previous MPU configurations.
Added herein are ARM_MPU_RESET and
ARM_MPU_EARLY_RESET. The former can be used
If the system is capable of booting and running
NuttX MPU configuration code without an MPU
violation. The latter is used if the system can
not run the bss and data initialization code.
These are options so that a NuttX may be configured to
not clobber a bootloader MPU configuration in a system
that is architected to share the MPU configuration task.
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