Arm-Cortex-R82: Add MPU support #1347
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portable/GCC/ARM_CR82/port.c
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| * regions are invalidated. | ||
| * The minimum region size is 64 Bytes. | ||
| */ | ||
| if( ( xRegions != NULL ) && ( xRegions[ ucIndex ].ulLengthInBytes > 64UL ) ) |
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Should the check be >= 64. Also, should we add an assert to help application writers to catch invalid length instead of silently ignoring them.
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Yes, that's correct. A new check has been added to help application writers catch invalid MPU region sizes.
portable/GCC/ARM_CR82/portmacro.h
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| #define portUNPRIVILEGED_FLASH_REGION ( 1ULL ) | ||
| #define portUNPRIVILEGED_SYSCALLS_REGION ( 2ULL ) | ||
| #define portPRIVILEGED_RAM_REGION ( 3ULL ) | ||
| #define portSTACK_REGION ( 0ULL ) |
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portSTACK_REGION is used to index the region in xRegionsSettings array but portSTACK_REGION and portPRIVILEGED_FLASH_REGION both being 0 makes it feel like we are using same MPU region for unprivileged flash and stack.
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Good catch, a new macro portSTACK_REGION_INDEX along with some comments have been introduced to make it clearer.
portable/GCC/ARM_CR82/portASM.S
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| .macro saveallgpregisters | ||
| /* Save all general-purpose registers on stack. */ | ||
| .macro portLOAD_MPU_REGIONS_ADDRESSES | ||
| MOV X3, #4 /* i = 4 First four MPU regions are already programmed.*/ |
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Possible to use some macro for this 4?
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Certainly, the portSTACK_REGION macro which is now defined with a value of 4 is used instead, also a comment has been added for better readability.
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This commit introduces support for the Memory Protection Unit (MPU) to the ARM Cortex-R82 port. The MPU enhances system security by allowing the definition of memory regions with specific access permissions. The following changes have been made: - Added MPU configuration functions in `port.c` to set up memory regions and their attributes. - Updated `portASM.S` to include assembly routines for MPU and context switching with MPU support. - Created `mpu_wrappers_v2_asm.c` to provide assembly wrappers for MPU operations. - Updated `portmacro.h` to include MPU-related macros and definitions. - Modified `task.h` to include MPU-related task attributes. - Updated `CMakeLists.txt` to include the new MPU source file. - Enhanced the `README.md` with instructions on MPU configuration. Signed-off-by: Ahmed Ismail <Ahmed.Ismail@arm.com>
This commit includes minor code improvements to enhance readability and maintainability of the Cortex-R82 port files. Changes include refactoring variable names, optimizing comments, and improving code structure without altering functionality. Signed-off-by: Ahmed Ismail <Ahmed.Ismail@arm.com>
This stack-depth check should not be performed for ports where portUSING_MPU_WRAPPERS is set to 1. In this case, pxTopOfStack and pxNewTCB->pxTopOfStack reside in different memory regions: pxTopOfStack is in unprivileged SRAM, while pxNewTCB->pxTopOfStack is in privileged SRAM. This is because pxPortInitialiseStack() returns the address of `ullContext` array rather than the decremented pxTopOfStack, as is done in the non-MPU case. Consequently, this check is not valid in this scenario. Signed-off-by: Ahmed Ismail <Ahmed.Ismail@arm.com>
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Description
This PR introduces the following:
Support for the Memory Protection Unit (MPU) to the ARM Cortex-R82 port. The MPU enhances system security by allowing the definition of memory regions with specific access permissions. The following changes have been made:
port.cto set up memory regions and their attributes.portASM.Sto include assembly routines for MPU and context switching with MPU support.mpu_wrappers_v2_asm.cto provide assembly wrappers for MPU operations.portmacro.hto include MPU-related macros and definitions.task.hto include MPU-related task attributes.CMakeLists.txtto include the new MPU source file.README.mdwith instructions on MPU configuration.Minor code improvements to enhance readability and maintainability of the Cortex-R82 port files. Changes include refactoring variable names and optimising comments without altering functionality.
This PR blocks Arm-Cortex-R82: Add SMP MPU examples PR.
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