348 lines
15 KiB
C
348 lines
15 KiB
C
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/*
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* FreeRTOS V202212.00
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* https://www.FreeRTOS.org
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* https://github.com/FreeRTOS
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*
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*/
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/* FreeRTOS includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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/**
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* @brief Size of the shared memory region.
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*/
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#define SHARED_MEMORY_SIZE 32
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/**
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* @brief Memory region shared between two tasks.
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*/
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static uint8_t ucSharedMemory[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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#if ( configTOTAL_MPU_REGIONS == 16 )
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static uint8_t ucSharedMemory1[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory2[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory3[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory4[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory5[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory6[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory7[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static uint8_t ucSharedMemory8[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) );
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#endif /* configTOTAL_MPU_REGIONS == 16 */
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/**
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* @brief Memory region used to track Memory Fault intentionally caused by the
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* RO Access task.
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*
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* RO Access task sets ucROTaskFaultTracker[ 0 ] to 1 before accessing illegal
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* memory. Illegal memory access causes Memory Fault and the fault handler
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* checks ucROTaskFaultTracker[ 0 ] to see if this is an expected fault. We
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* recover gracefully from an expected fault by jumping to the next instruction.
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*
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* @note We are declaring a region of 32 bytes even though we need only one. The
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* reason is that the size of an MPU region must be a multiple of 32 bytes.
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*/
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static volatile uint8_t ucROTaskFaultTracker[ SHARED_MEMORY_SIZE ] __attribute__( ( aligned( 32 ) ) ) = { 0 };
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/*-----------------------------------------------------------*/
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/**
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* @brief Implements the task which has Read Only access to the memory region
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* ucSharedMemory.
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*
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* @param pvParameters[in] Parameters as passed during task creation.
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*/
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static void prvROAccessTask( void * pvParameters );
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/**
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* @brief Implements the task which has Read Write access to the memory region
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* ucSharedMemory.
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*
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* @param pvParameters[in] Parameters as passed during task creation.
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*/
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static void prvRWAccessTask( void * pvParameters );
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/*-----------------------------------------------------------*/
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static void prvROAccessTask( void * pvParameters )
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{
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uint8_t ucVal;
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/* Unused parameters. */
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( void ) pvParameters;
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for( ; ; )
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{
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/* This task performs the following sequence for all the shared memory
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* regions:
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*
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* 1. Perfrom a read access to the shared memory. Since this task has
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* RO access to the shared memory, the read operation is successful.
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*
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* 2. Set ucROTaskFaultTracker[ 0 ] to 1 before performing a write to
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* the shared memory. Since this task has Read Only access to the
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* shared memory, the write operation would result in a Memory Fault.
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* Setting ucROTaskFaultTracker[ 0 ] to 1 tells the Memory Fault
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* Handler that this is an expected fault. The handler recovers from
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* the expected fault gracefully by jumping to the next instruction.
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*
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* 3. Perfrom a write to the shared memory resulting in a memory fault.
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*
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* 4. Ensure that the write access did generate MemFault and the fault
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* handler did clear the ucROTaskFaultTracker[ 0 ].
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*/
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/* Perform the above mentioned sequence on ucSharedMemory. */
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ucVal = ucSharedMemory[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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#if ( configTOTAL_MPU_REGIONS == 16 )
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{
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/* Perform the above mentioned sequence on ucSharedMemory1. */
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ucVal = ucSharedMemory1[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory1[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory2. */
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ucVal = ucSharedMemory2[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory2[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory3. */
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ucVal = ucSharedMemory3[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory3[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory4. */
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ucVal = ucSharedMemory4[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory4[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory5. */
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ucVal = ucSharedMemory5[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory5[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory6. */
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ucVal = ucSharedMemory6[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory6[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory7. */
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ucVal = ucSharedMemory7[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory7[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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/* Perform the above mentioned sequence on ucSharedMemory8. */
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ucVal = ucSharedMemory8[ 0 ];
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/* Silent compiler warnings about unused variables. */
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( void ) ucVal;
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ucROTaskFaultTracker[ 0 ] = 1;
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ucSharedMemory8[ 0 ] = 0;
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configASSERT( ucROTaskFaultTracker[ 0 ] == 0 );
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}
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#endif /* configTOTAL_MPU_REGIONS == 16 */
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/* Wait for a second. */
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vTaskDelay( pdMS_TO_TICKS( 1000 ) );
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}
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}
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/*-----------------------------------------------------------*/
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static void prvRWAccessTask( void * pvParameters )
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{
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/* Unused parameters. */
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( void ) pvParameters;
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for( ; ; )
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{
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/* This task has RW access to ucSharedMemory and therefore can write to
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* it. */
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ucSharedMemory[ 0 ] = 0;
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#if ( configTOTAL_MPU_REGIONS == 16 )
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{
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ucSharedMemory1[ 0 ] = 0;
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ucSharedMemory2[ 0 ] = 0;
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ucSharedMemory3[ 0 ] = 0;
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ucSharedMemory4[ 0 ] = 0;
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ucSharedMemory5[ 0 ] = 0;
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ucSharedMemory6[ 0 ] = 0;
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ucSharedMemory7[ 0 ] = 0;
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ucSharedMemory8[ 0 ] = 0;
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}
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#endif /* configTOTAL_MPU_REGIONS == 16 */
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/* Wait for a second. */
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vTaskDelay( pdMS_TO_TICKS( 1000 ) );
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}
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}
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/*-----------------------------------------------------------*/
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void vStartMPUDemo( void )
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{
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static StackType_t xROAccessTaskStack[ configMINIMAL_STACK_SIZE ] __attribute__( ( aligned( 32 ) ) );
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static StackType_t xRWAccessTaskStack[ configMINIMAL_STACK_SIZE ] __attribute__( ( aligned( 32 ) ) );
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TaskParameters_t xROAccessTaskParameters =
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{
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.pvTaskCode = prvROAccessTask,
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.pcName = "ROAccess",
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.usStackDepth = configMINIMAL_STACK_SIZE,
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.pvParameters = NULL,
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.uxPriority = tskIDLE_PRIORITY,
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.puxStackBuffer = xROAccessTaskStack,
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.xRegions =
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{
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{ ( void * ) ucSharedMemory, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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#if ( configTOTAL_MPU_REGIONS == 16 )
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{ ( void * ) ucSharedMemory1, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory2, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory3, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory4, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory5, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory6, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory7, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory8, 32, tskMPU_REGION_READ_ONLY | tskMPU_REGION_EXECUTE_NEVER },
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#endif /* configTOTAL_MPU_REGIONS == 16 */
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{ ( void * ) ucROTaskFaultTracker, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ 0, 0, 0 },
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}
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};
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TaskParameters_t xRWAccessTaskParameters =
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{
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.pvTaskCode = prvRWAccessTask,
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.pcName = "RWAccess",
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.usStackDepth = configMINIMAL_STACK_SIZE,
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.pvParameters = NULL,
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.uxPriority = tskIDLE_PRIORITY,
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.puxStackBuffer = xRWAccessTaskStack,
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.xRegions =
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{
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{ ( void * ) ucSharedMemory, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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#if ( configTOTAL_MPU_REGIONS == 16 )
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{ ( void * ) ucSharedMemory1, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory2, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory3, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory4, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory5, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory6, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory7, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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{ ( void * ) ucSharedMemory8, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
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#endif /* configTOTAL_MPU_REGIONS == 16 */
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{ 0, 0, 0 },
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{ 0, 0, 0 },
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}
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};
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/* Create an unprivileged task with RO access to ucSharedMemory. */
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xTaskCreateRestricted( &( xROAccessTaskParameters ), NULL );
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/* Create an unprivileged task with RW access to ucSharedMemory. */
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xTaskCreateRestricted( &( xRWAccessTaskParameters ), NULL );
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}
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/*-----------------------------------------------------------*/
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portDONT_DISCARD void vHandleMemoryFault( uint32_t * pulFaultStackAddress )
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{
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uint32_t ulPC;
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uint16_t usOffendingInstruction;
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/* Is this an expected fault? */
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if( ucROTaskFaultTracker[ 0 ] == 1 )
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{
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/* Read program counter. */
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ulPC = pulFaultStackAddress[ 6 ];
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/* Read the offending instruction. */
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usOffendingInstruction = *( uint16_t * ) ulPC;
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/* From ARM docs:
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* If the value of bits[15:11] of the halfword being decoded is one of
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* the following, the halfword is the first halfword of a 32-bit
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* instruction:
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* - 0b11101.
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* - 0b11110.
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* - 0b11111.
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* Otherwise, the halfword is a 16-bit instruction.
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*/
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/* Extract bits[15:11] of the offending instruction. */
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usOffendingInstruction = usOffendingInstruction & 0xF800;
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usOffendingInstruction = ( usOffendingInstruction >> 11 );
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/* Determine if the offending instruction is a 32-bit instruction or
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* a 16-bit instruction. */
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if( ( usOffendingInstruction == 0x001F ) ||
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( usOffendingInstruction == 0x001E ) ||
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( usOffendingInstruction == 0x001D ) )
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{
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/* Since the offending instruction is a 32-bit instruction,
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* increment the program counter by 4 to move to the next
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* instruction. */
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ulPC += 4;
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}
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else
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{
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/* Since the offending instruction is a 16-bit instruction,
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* increment the program counter by 2 to move to the next
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* instruction. */
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ulPC += 2;
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}
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|
|
|
||
|
|
/* Save the new program counter on the stack. */
|
||
|
|
pulFaultStackAddress[ 6 ] = ulPC;
|
||
|
|
|
||
|
|
/* Mark the fault as handled. */
|
||
|
|
ucROTaskFaultTracker[ 0 ] = 0;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* This is an unexpected fault - loop forever. */
|
||
|
|
for( ; ; )
|
||
|
|
{
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
/*-----------------------------------------------------------*/
|