arm: mpu: Unify ARM_MPU kconfig definitions

Previously, there were two separate Kconfig definitions
of ARM_MPU located at:
- arch/arm/core/mpu/Kconfig
- arch/arm64/core/cortex_r/Kconfig

This lead to incomplete default settings and unexpected
missing configurations.

This commit combines the two into a single unified definition
now located at arch/common/Kconfig to prevent this.

Signed-off-by: Samuel Chee <samche01@arm.com>

arch/arm/core/mpu/Kconfig

@@ -5,47 +5,6 @@
 
 if CPU_HAS_MPU
 
-config ARM_MPU
-	bool "ARM MPU Support"
-	select MPU
-	select SRAM_REGION_PERMISSIONS
-	select THREAD_STACK_INFO
-	select ARCH_HAS_EXECUTABLE_PAGE_BIT
-	select MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT if !(CPU_HAS_NXP_SYSMPU || ARMV8_M_BASELINE || ARMV8_M_MAINLINE || AARCH32_ARMV8_R)
-	select MPU_REQUIRES_NON_OVERLAPPING_REGIONS if CPU_HAS_ARM_MPU && (ARMV8_M_BASELINE || ARMV8_M_MAINLINE || AARCH32_ARMV8_R)
-	select MPU_GAP_FILLING if AARCH32_ARMV8_R
-	select ARCH_MEM_DOMAIN_SUPPORTS_ISOLATED_STACKS
-	select MEM_DOMAIN_ISOLATED_STACKS
-	help
-	  MCU implements Memory Protection Unit.
-
-	  Notes:
-	  The ARMv6-M and ARMv7-M MPU architecture requires a power-of-two
-	  alignment of MPU region base address and size.
-
-	  The NXP MPU as well as the ARMv8-M MPU do not require MPU regions
-	  to have power-of-two alignment for base address and region size.
-
-	  The ARMv8-M MPU requires the active MPU regions be non-overlapping.
-	  As a result of this, the ARMv8-M MPU needs to fully partition the
-	  memory map when programming dynamic memory regions (e.g. PRIV stack
-	  guard, user thread stack, and application memory domains), if the
-	  system requires PRIV access policy different from the access policy
-	  of the ARMv8-M background memory map. The application developer may
-	  enforce full PRIV (kernel) memory partition by enabling the
-	  CONFIG_MPU_GAP_FILLING option.
-	  By not enforcing full partition, MPU may leave part of kernel
-	  SRAM area covered only by the default ARMv8-M memory map. This
-	  is fine for User Mode, since the background ARM map does not
-	  allow nPRIV access at all. However, since the background map
-	  policy allows instruction fetches by privileged code, forcing
-	  this Kconfig option off prevents the system from directly
-	  triggering MemManage exceptions upon accidental attempts to
-	  execute code from SRAM in XIP builds.
-	  Since this does not compromise User Mode, we make the skipping
-	  of full partitioning the default behavior for the ARMv8-M MPU
-	  driver.
-
 config ARM_MPU_REGION_MIN_ALIGN_AND_SIZE
 	int
 	default 256 if ARM_MPU && ARMV6_M_ARMV8_M_BASELINE && !ARMV8_M_BASELINE

arch/arm64/core/cortex_r/Kconfig

@@ -7,39 +7,6 @@
 
 if CPU_HAS_MPU
 
-config ARM_MPU
-	bool "ARM MPU Support"
-	select THREAD_STACK_INFO
-	select MPU
-	select SRAM_REGION_PERMISSIONS
-	select ARCH_MEM_DOMAIN_SYNCHRONOUS_API if USERSPACE
-	default y
-	help
-	  MPU implements Memory Protection Unit.
-
-	  Notes:
-	  The ARMv8-R MPU architecture requires a power-of-two alignment
-	  of MPU region base address and size(64 bytes aligned).
-
-	  The ARMv8-R MPU requires the active MPU regions be non-overlapping.
-	  As a result of this, the ARMv8-R MPU needs to fully partition the
-	  memory map when programming dynamic memory regions (e.g. PRIV stack
-	  guard, user thread stack, and application memory domains), if the
-	  system requires PRIV access policy different from the access policy
-	  of the ARMv8-R background memory map. The application developer may
-	  enforce full PRIV (kernel) memory partition by enabling the
-	  CONFIG_MPU_GAP_FILLING option.
-	  By not enforcing full partition, MPU may leave part of kernel
-	  SRAM area covered only by the default ARMv8-R memory map. This
-	  is fine for User Mode, since the background ARM map does not
-	  allow nPRIV access at all. However, since the background map
-	  policy allows instruction fetches by privileged code, forcing
-	  this Kconfig option off prevents the system from directly
-	  triggering MemManage exceptions upon accidental attempts to
-	  execute code from SRAM in XIP builds.
-	  Since this does not compromise User Mode, we make the skipping
-	  of full partitioning the default behavior for the ARMv8-R MPU
-	  driver.
 
 config ARM_MPU_REGION_MIN_ALIGN_AND_SIZE
 	int

arch/common/Kconfig

@@ -37,3 +37,47 @@ config ISR_TABLE_SHELL
 	depends on SHELL
 	help
 	  This option enables a shell command to dump the ISR tables.
+
+
+config ARM_MPU
+	bool "ARM MPU Support"
+	select MPU
+	select SRAM_REGION_PERMISSIONS
+	select THREAD_STACK_INFO
+	select ARCH_HAS_EXECUTABLE_PAGE_BIT if (CPU_AARCH32_CORTEX_R || CPU_CORTEX_M)
+	select MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT if !(CPU_HAS_NXP_SYSMPU || ARMV8_M_BASELINE || ARMV8_M_MAINLINE || AARCH32_ARMV8_R)
+	select MPU_REQUIRES_NON_OVERLAPPING_REGIONS if CPU_HAS_ARM_MPU && (ARMV8_M_BASELINE || ARMV8_M_MAINLINE || AARCH32_ARMV8_R)
+	select MPU_GAP_FILLING if AARCH32_ARMV8_R
+	select ARCH_MEM_DOMAIN_SUPPORTS_ISOLATED_STACKS if (CPU_AARCH32_CORTEX_R || CPU_CORTEX_M)
+	select ARCH_MEM_DOMAIN_SYNCHRONOUS_API if USERSPACE && CPU_AARCH64_CORTEX_R
+	default y if CPU_AARCH64_CORTEX_R
+	depends on CPU_HAS_MPU
+	help
+	  MCU implements Memory Protection Unit.
+
+	  Notes:
+	  The ARMv6-M, ARMv7-M, and ARMv8-R MPU MPU architecture requires a power-of-two
+	  alignment of MPU region base address and size.
+
+	  The NXP MPU as well as the ARMv8-M MPU do not require MPU regions
+	  to have power-of-two alignment for base address and region size.
+
+	  The ARMv8-M and ARMv8-R MPU requires the active MPU regions be non-overlapping.
+	  As a result of this, both respective MPUs needs to fully partition the
+	  memory map when programming dynamic memory regions (e.g. PRIV stack
+	  guard, user thread stack, and application memory domains), if the
+	  system requires PRIV access policy different from the access policy
+	  of the ARMv8-M or ARMv8-R background memory map. The application developer may
+	  enforce full PRIV (kernel) memory partition by enabling the
+	  MPU_GAP_FILLING option.
+	  By not enforcing full partition, MPU may leave part of kernel
+	  SRAM area covered only by the default ARMv8-M or ARMv8-R memory map. This
+	  is fine for User Mode, since the background ARM map does not
+	  allow nPRIV access at all. However, since the background map
+	  policy allows instruction fetches by privileged code, forcing
+	  this Kconfig option off prevents the system from directly
+	  triggering MemManage exceptions upon accidental attempts to
+	  execute code from SRAM in XIP builds.
+	  Since this does not compromise User Mode, we make the skipping
+	  of full partitioning the default behavior for the ARMv8-M and ARMv8-R MPU
+	  driver.