/* * FreeRTOS Kernel V10.5.1 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * SPDX-License-Identifier: MIT * * Permission is hereby granted, free of charge, to any person obtaining a copy of * this software and associated documentation files (the "Software"), to deal in * the Software without restriction, including without limitation the rights to * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of * the Software, and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * https://www.FreeRTOS.org * https://github.com/FreeRTOS * */ /* * A sample implementation of pvPortMalloc() and vPortFree() that permits * allocated blocks to be freed, but does not combine adjacent free blocks * into a single larger block (and so will fragment memory). See heap_4.c for * an equivalent that does combine adjacent blocks into single larger blocks. * * See heap_1.c, heap_3.c and heap_4.c for alternative implementations, and the * memory management pages of https://www.FreeRTOS.org for more information. */ #include #include /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining * all the API functions to use the MPU wrappers. That should only be done when * task.h is included from an application file. */ #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE #include "FreeRTOS.h" #include "task.h" #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE #if ( configSUPPORT_DYNAMIC_ALLOCATION == 0 ) #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0 #endif #ifndef configHEAP_CLEAR_MEMORY_ON_FREE #define configHEAP_CLEAR_MEMORY_ON_FREE 0 #endif /* A few bytes might be lost to byte aligning the heap start address. */ #define configADJUSTED_HEAP_SIZE ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT ) /* Assumes 8bit bytes! */ #define heapBITS_PER_BYTE ( ( size_t ) 8 ) /* Max value that fits in a size_t type. */ #define heapSIZE_MAX ( ~( ( size_t ) 0 ) ) /* Check if multiplying a and b will result in overflow. */ #define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) ) /* Check if adding a and b will result in overflow. */ #define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) ) /* MSB of the xBlockSize member of an BlockLink_t structure is used to track * the allocation status of a block. When MSB of the xBlockSize member of * an BlockLink_t structure is set then the block belongs to the application. * When the bit is free the block is still part of the free heap space. */ #define heapBLOCK_ALLOCATED_BITMASK ( ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 ) ) #define heapBLOCK_SIZE_IS_VALID( xBlockSize ) ( ( ( xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) == 0 ) #define heapBLOCK_IS_ALLOCATED( pxBlock ) ( ( ( pxBlock->xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) != 0 ) #define heapALLOCATE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) |= heapBLOCK_ALLOCATED_BITMASK ) #define heapFREE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) &= ~heapBLOCK_ALLOCATED_BITMASK ) /*-----------------------------------------------------------*/ /* Allocate the memory for the heap. */ #if ( configAPPLICATION_ALLOCATED_HEAP == 1 ) /* The application writer has already defined the array used for the RTOS * heap - probably so it can be placed in a special segment or address. */ extern uint8_t ucHeap[ configTOTAL_HEAP_SIZE ]; #else PRIVILEGED_DATA static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ]; #endif /* configAPPLICATION_ALLOCATED_HEAP */ /* Define the linked list structure. This is used to link free blocks in order * of their size. */ typedef struct A_BLOCK_LINK { struct A_BLOCK_LINK * pxNextFreeBlock; /*<< The next free block in the list. */ size_t xBlockSize; /*<< The size of the free block. */ } BlockLink_t; static const uint16_t heapSTRUCT_SIZE = ( ( sizeof( BlockLink_t ) + ( portBYTE_ALIGNMENT - 1 ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK ) ); #define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) ) /* Create a couple of list links to mark the start and end of the list. */ PRIVILEGED_DATA static BlockLink_t xStart, xEnd; /* Keeps track of the number of free bytes remaining, but says nothing about * fragmentation. */ PRIVILEGED_DATA static size_t xFreeBytesRemaining = configADJUSTED_HEAP_SIZE; /*-----------------------------------------------------------*/ /* * Initialises the heap structures before their first use. */ static void prvHeapInit( void ) PRIVILEGED_FUNCTION; /*-----------------------------------------------------------*/ /* STATIC FUNCTIONS ARE DEFINED AS MACROS TO MINIMIZE THE FUNCTION CALL DEPTH. */ /* * Insert a block into the list of free blocks - which is ordered by size of * the block. Small blocks at the start of the list and large blocks at the end * of the list. */ #define prvInsertBlockIntoFreeList( pxBlockToInsert ) \ { \ BlockLink_t * pxIterator; \ size_t xBlockSize; \ \ xBlockSize = pxBlockToInsert->xBlockSize; \ \ /* Iterate through the list until a block is found that has a larger size */ \ /* than the block we are inserting. */ \ for( pxIterator = &xStart; pxIterator->pxNextFreeBlock->xBlockSize < xBlockSize; pxIterator = pxIterator->pxNextFreeBlock ) \ { \ /* There is nothing to do here - just iterate to the correct position. */ \ } \ \ /* Update the list to include the block being inserted in the correct */ \ /* position. */ \ pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock; \ pxIterator->pxNextFreeBlock = pxBlockToInsert; \ } /*-----------------------------------------------------------*/ void * pvPortMalloc( size_t xWantedSize ) { BlockLink_t * pxBlock; BlockLink_t * pxPreviousBlock; BlockLink_t * pxNewBlockLink; PRIVILEGED_DATA static BaseType_t xHeapHasBeenInitialised = pdFALSE; void * pvReturn = NULL; size_t xAdditionalRequiredSize; vTaskSuspendAll(); { /* If this is the first call to malloc then the heap will require * initialisation to setup the list of free blocks. */ if( xHeapHasBeenInitialised == pdFALSE ) { prvHeapInit(); xHeapHasBeenInitialised = pdTRUE; } if( xWantedSize > 0 ) { /* The wanted size must be increased so it can contain a BlockLink_t * structure in addition to the requested amount of bytes. Some * additional increment may also be needed for alignment. */ xAdditionalRequiredSize = heapSTRUCT_SIZE + portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ); if( heapADD_WILL_OVERFLOW( xWantedSize, xAdditionalRequiredSize ) == 0 ) { xWantedSize += xAdditionalRequiredSize; } else { xWantedSize = 0; } } /* Check the block size we are trying to allocate is not so large that the * top bit is set. The top bit of the block size member of the BlockLink_t * structure is used to determine who owns the block - the application or * the kernel, so it must be free. */ if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 ) { if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) ) { /* Blocks are stored in byte order - traverse the list from the start * (smallest) block until one of adequate size is found. */ pxPreviousBlock = &xStart; pxBlock = xStart.pxNextFreeBlock; while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) ) { pxPreviousBlock = pxBlock; pxBlock = pxBlock->pxNextFreeBlock; } /* If we found the end marker then a block of adequate size was not found. */ if( pxBlock != &xEnd ) { /* Return the memory space - jumping over the BlockLink_t structure * at its start. */ pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + heapSTRUCT_SIZE ); /* This block is being returned for use so must be taken out of the * list of free blocks. */ pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock; /* If the block is larger than required it can be split into two. */ if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE ) { /* This block is to be split into two. Create a new block * following the number of bytes requested. The void cast is * used to prevent byte alignment warnings from the compiler. */ pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize ); /* Calculate the sizes of two blocks split from the single * block. */ pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize; pxBlock->xBlockSize = xWantedSize; /* Insert the new block into the list of free blocks. */ prvInsertBlockIntoFreeList( ( pxNewBlockLink ) ); } xFreeBytesRemaining -= pxBlock->xBlockSize; /* The block is being returned - it is allocated and owned * by the application and has no "next" block. */ heapALLOCATE_BLOCK( pxBlock ); pxBlock->pxNextFreeBlock = NULL; } } } traceMALLOC( pvReturn, xWantedSize ); } ( void ) xTaskResumeAll(); #if ( configUSE_MALLOC_FAILED_HOOK == 1 ) { if( pvReturn == NULL ) { vApplicationMallocFailedHook(); } } #endif return pvReturn; } /*-----------------------------------------------------------*/ void vPortFree( void * pv ) { uint8_t * puc = ( uint8_t * ) pv; BlockLink_t * pxLink; if( pv != NULL ) { /* The memory being freed will have an BlockLink_t structure immediately * before it. */ puc -= heapSTRUCT_SIZE; /* This unexpected casting is to keep some compilers from issuing * byte alignment warnings. */ pxLink = ( void * ) puc; configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( pxLink->pxNextFreeBlock == NULL ); if( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ) { if( pxLink->pxNextFreeBlock == NULL ) { /* The block is being returned to the heap - it is no longer * allocated. */ heapFREE_BLOCK( pxLink ); #if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 ) { ( void ) memset( puc + heapSTRUCT_SIZE, 0, pxLink->xBlockSize - heapSTRUCT_SIZE ); } #endif vTaskSuspendAll(); { /* Add this block to the list of free blocks. */ prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) ); xFreeBytesRemaining += pxLink->xBlockSize; traceFREE( pv, pxLink->xBlockSize ); } ( void ) xTaskResumeAll(); } } } } /*-----------------------------------------------------------*/ size_t xPortGetFreeHeapSize( void ) { return xFreeBytesRemaining; } /*-----------------------------------------------------------*/ void vPortInitialiseBlocks( void ) { /* This just exists to keep the linker quiet. */ } /*-----------------------------------------------------------*/ void * pvPortCalloc( size_t xNum, size_t xSize ) { void * pv = NULL; if( heapMULTIPLY_WILL_OVERFLOW( xNum, xSize ) == 0 ) { pv = pvPortMalloc( xNum * xSize ); if( pv != NULL ) { ( void ) memset( pv, 0, xNum * xSize ); } } return pv; } /*-----------------------------------------------------------*/ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */ { BlockLink_t * pxFirstFreeBlock; uint8_t * pucAlignedHeap; /* Ensure the heap starts on a correctly aligned boundary. */ pucAlignedHeap = ( uint8_t * ) ( ( ( portPOINTER_SIZE_TYPE ) & ucHeap[ portBYTE_ALIGNMENT - 1 ] ) & ( ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK ) ) ); /* xStart is used to hold a pointer to the first item in the list of free * blocks. The void cast is used to prevent compiler warnings. */ xStart.pxNextFreeBlock = ( void * ) pucAlignedHeap; xStart.xBlockSize = ( size_t ) 0; /* xEnd is used to mark the end of the list of free blocks. */ xEnd.xBlockSize = configADJUSTED_HEAP_SIZE; xEnd.pxNextFreeBlock = NULL; /* To start with there is a single free block that is sized to take up the * entire heap space. */ pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap; pxFirstFreeBlock->xBlockSize = configADJUSTED_HEAP_SIZE; pxFirstFreeBlock->pxNextFreeBlock = &xEnd; } /*-----------------------------------------------------------*/