# Memory Protection Unit (MPU) configuration options

# Copyright (c) 2017 Linaro Limited
# SPDX-License-Identifier: Apache-2.0

if CPU_HAS_MPU

config ARM_MPU_REGION_MIN_ALIGN_AND_SIZE
	int
	default 256 if ARM_MPU && ARMV6_M_ARMV8_M_BASELINE && !ARMV8_M_BASELINE
	default 128 if ARM_MPU && FPU_SHARING && MPU_STACK_GUARD
	default 64 if ARM_MPU && AARCH32_ARMV8_R
	default 32 if ARM_MPU
	default 4
	help
	  Minimum size (and alignment) of an ARM MPU region. Use this
	  symbol to guarantee minimum size and alignment of MPU regions.
	  A minimum 4-byte alignment is enforced in ARM builds without
	  support for Memory Protection.

if ARM_MPU

config MPU_STACK_GUARD
	bool "Thread Stack Guards"
	help
	  Enable Thread Stack Guards via MPU

config MPU_STACK_GUARD_MIN_SIZE_FLOAT
	int
	depends on MPU_STACK_GUARD
	depends on FPU_SHARING
	default 128
	help
	  Minimum size (and alignment when applicable) of an ARM MPU
	  region, which guards the stack of a thread that is using the
	  Floating Point (FP) context. The width of the guard is set to
	  128, to accommodate the length of a Cortex-M exception stack
	  frame when the floating point context is active. The FP context
	  is only stacked in sharing FP registers mode, therefore, the
	  option is applicable only when FPU_SHARING is selected.

config MPU_ALLOW_FLASH_WRITE
	bool "Add MPU access to write to flash"
	help
	  Enable this to allow MPU RWX access to flash memory

config MPU_DISABLE_BACKGROUND_MAP
	bool "Disables the default background address map"
	help
	  Enable this to turn off the default background MPU address map. Your
	  SoC definition should likely provide its own custom MPU regions.

config CUSTOM_SECTION_ALIGN
	bool "Custom Section Align"
	help
	  MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT(ARMv7-M) sometimes cause memory
	  wasting in linker scripts defined memory sections. Use this symbol
	  to guarantee user custom section align size to avoid more memory used
	  for respect alignment. But that needs carefully configure MPU region
	  and sub-regions(ARMv7-M) to cover this feature.

config CUSTOM_SECTION_MIN_ALIGN_SIZE
	int "Custom Section Align Size"
	default 32
	help
	  Custom align size of memory section in linker scripts. Usually
	  it should consume less alignment memory. Although this alignment
	  size is configured by users, it must also respect the power of
	  two regulation if hardware requires.

endif # ARM_MPU

endif # CPU_HAS_MPU