arch: arm: aarch32: add ARMv8-R MPU support

ARMv8-R aarch32 processor has support for
ARM PMSAv8-32. To add support for ARMv8-R we reuse the
ARMv8-M effort and change access to the different registers
such as rbar, rlar, mair, prselr.

Signed-off-by: Julien Massot <[email protected]>
Signed-off-by: Manuel Arguelles <[email protected]>

Author: Julien Massot

arch/arm/core/aarch32/mpu/Kconfig

@@ -12,7 +12,8 @@ config ARM_MPU
 	select THREAD_STACK_INFO
 	select ARCH_HAS_EXECUTABLE_PAGE_BIT
 	select MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT if !(CPU_HAS_NXP_MPU || ARMV8_M_BASELINE || ARMV8_M_MAINLINE)
-	select MPU_REQUIRES_NON_OVERLAPPING_REGIONS if CPU_HAS_ARM_MPU && (ARMV8_M_BASELINE || ARMV8_M_MAINLINE)
+	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
 	help
 	  MCU implements Memory Protection Unit.
 
@@ -46,6 +47,7 @@ config ARM_MPU
 config ARM_MPU_REGION_MIN_ALIGN_AND_SIZE
 	int
 	default 256 if ARM_MPU && ARMV6_M_ARMV8_M_BASELINE && !ARMV8_M_BASELINE
+	default 64 if ARM_MPU && AARCH32_ARMV8_R
 	default 32 if ARM_MPU
 	default 4
 	help

arch/arm/core/aarch32/mpu/arm_core_mpu.c

@@ -155,6 +155,8 @@ void z_arm_configure_static_mpu_regions(void)
 #endif /* CONFIG_MPU_REQUIRES_NON_OVERLAPPING_REGIONS */
 }
 
+extern void arm_core_mpu_enable(void);
+extern void arm_core_mpu_disable(void);
 /**
  * @brief Use the HW-specific MPU driver to program
  *        the dynamic MPU regions.
@@ -303,8 +305,14 @@ void z_arm_configure_dynamic_mpu_regions(struct k_thread *thread)
 #endif /* CONFIG_MPU_STACK_GUARD */
 
 	/* Configure the dynamic MPU regions */
+#ifdef CONFIG_AARCH32_ARMV8_R
+	arm_core_mpu_disable();
+#endif
 	arm_core_mpu_configure_dynamic_mpu_regions(dynamic_regions,
 						   region_num);
+#ifdef CONFIG_AARCH32_ARMV8_R
+	arm_core_mpu_enable();
+#endif
 }
 
 #if defined(CONFIG_USERSPACE)

arch/arm/core/aarch32/mpu/arm_mpu.c

@@ -43,11 +43,12 @@ static uint8_t static_regions_num;
 	defined(CONFIG_CPU_CORTEX_M3) || \
 	defined(CONFIG_CPU_CORTEX_M4) || \
 	defined(CONFIG_CPU_CORTEX_M7) || \
-	defined(CONFIG_CPU_AARCH32_CORTEX_R)
+	defined(CONFIG_ARMV7_R)
 #include "arm_mpu_v7_internal.h"
 #elif defined(CONFIG_CPU_CORTEX_M23) || \
 	defined(CONFIG_CPU_CORTEX_M33) || \
-	defined(CONFIG_CPU_CORTEX_M55)
+	defined(CONFIG_CPU_CORTEX_M55) || \
+	defined(CONFIG_AARCH32_ARMV8_R)
 #include "arm_mpu_v8_internal.h"
 #else
 #error "Unsupported ARM CPU"
@@ -84,7 +85,7 @@ static int mpu_configure_region(const uint8_t index,
 
 	/* Populate internal ARM MPU region configuration structure. */
 	region_conf.base = new_region->start;
-#if defined(CONFIG_CPU_AARCH32_CORTEX_R)
+#if defined(CONFIG_ARMV7_R)
 	region_conf.size = size_to_mpu_rasr_size(new_region->size);
 #endif
 	get_region_attr_from_mpu_partition_info(&region_conf.attr,