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/*
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
* 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 combines
* (coalescences) adjacent memory blocks as they are freed, and in so doing
* limits memory fragmentation.
*
* See heap_1.c, heap_2.c and heap_3.c for alternative implementations, and the
* memory management pages of https://www.FreeRTOS.org for more information.
*/
#include <stdlib.h>
#include <string.h>
/* 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
/* Block sizes must not get too small. */
#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
/* 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 memory address. */
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;
/*-----------------------------------------------------------*/
/*
* Inserts a block of memory that is being freed into the correct position in
* the list of free memory blocks. The block being freed will be merged with
* the block in front it and/or the block behind it if the memory blocks are
* adjacent to each other.
*/
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) PRIVILEGED_FUNCTION;
/*
* Called automatically to setup the required heap structures the first time
* pvPortMalloc() is called.
*/
static void prvHeapInit( void ) PRIVILEGED_FUNCTION;
/*-----------------------------------------------------------*/
/* The size of the structure placed at the beginning of each allocated memory
* block must by correctly byte aligned. */
static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
/* Create a couple of list links to mark the start and end of the list. */
PRIVILEGED_DATA static BlockLink_t xStart;
PRIVILEGED_DATA static BlockLink_t * pxEnd = NULL;
/* Keeps track of the number of calls to allocate and free memory as well as the
* number of free bytes remaining, but says nothing about fragmentation. */
PRIVILEGED_DATA static size_t xFreeBytesRemaining = 0U;
PRIVILEGED_DATA static size_t xMinimumEverFreeBytesRemaining = 0U;
PRIVILEGED_DATA static size_t xNumberOfSuccessfulAllocations = 0;
PRIVILEGED_DATA static size_t xNumberOfSuccessfulFrees = 0;
/*-----------------------------------------------------------*/
void * pvPortMalloc( size_t xWantedSize )
{
BlockLink_t * pxBlock;
BlockLink_t * pxPreviousBlock;
BlockLink_t * pxNewBlockLink;
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( pxEnd == NULL )
{
prvHeapInit();
}
else
{
mtCOVERAGE_TEST_MARKER();
}
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. */
if( heapADD_WILL_OVERFLOW( xWantedSize, xHeapStructSize ) == 0 )
{
xWantedSize += xHeapStructSize;
/* Ensure that blocks are always aligned to the required number
* of bytes. */
if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 )
{
/* Byte alignment required. */
xAdditionalRequiredSize = portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK );
if( heapADD_WILL_OVERFLOW( xWantedSize, xAdditionalRequiredSize ) == 0 )
{
xWantedSize += xAdditionalRequiredSize;
}
else
{
xWantedSize = 0;
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
xWantedSize = 0;
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
/* 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 ) )
{
/* Traverse the list from the start (lowest address) 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 the end marker was reached then a block of adequate size
* was not found. */
if( pxBlock != pxEnd )
{
/* Return the memory space pointed to - jumping over the
* BlockLink_t structure at its start. */
pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize );
/* 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 );
configASSERT( ( ( ( size_t ) pxNewBlockLink ) & portBYTE_ALIGNMENT_MASK ) == 0 );
/* 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 );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
xFreeBytesRemaining -= pxBlock->xBlockSize;
if( xFreeBytesRemaining < xMinimumEverFreeBytesRemaining )
{
xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
/* The block is being returned - it is allocated and owned
* by the application and has no "next" block. */
heapALLOCATE_BLOCK( pxBlock );
pxBlock->pxNextFreeBlock = NULL;
xNumberOfSuccessfulAllocations++;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
traceMALLOC( pvReturn, xWantedSize );
}
( void ) xTaskResumeAll();
#if ( configUSE_MALLOC_FAILED_HOOK == 1 )
{
if( pvReturn == NULL )
{
vApplicationMallocFailedHook();
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
#endif /* if ( configUSE_MALLOC_FAILED_HOOK == 1 ) */
configASSERT( ( ( ( size_t ) pvReturn ) & ( size_t ) portBYTE_ALIGNMENT_MASK ) == 0 );
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 -= xHeapStructSize;
/* This casting is to keep the compiler from issuing 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 + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
}
#endif
vTaskSuspendAll();
{
/* Add this block to the list of free blocks. */
xFreeBytesRemaining += pxLink->xBlockSize;
traceFREE( pv, pxLink->xBlockSize );
prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) );
xNumberOfSuccessfulFrees++;
}
( void ) xTaskResumeAll();
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
}
/*-----------------------------------------------------------*/
size_t xPortGetFreeHeapSize( void )
{
return xFreeBytesRemaining;
}
/*-----------------------------------------------------------*/
size_t xPortGetMinimumEverFreeHeapSize( void )
{
return xMinimumEverFreeBytesRemaining;
}
/*-----------------------------------------------------------*/
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;
portPOINTER_SIZE_TYPE uxAddress;
size_t xTotalHeapSize = configTOTAL_HEAP_SIZE;
/* Ensure the heap starts on a correctly aligned boundary. */
uxAddress = ( portPOINTER_SIZE_TYPE ) ucHeap;
if( ( uxAddress & portBYTE_ALIGNMENT_MASK ) != 0 )
{
uxAddress += ( portBYTE_ALIGNMENT - 1 );
uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
xTotalHeapSize -= ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) ucHeap );
}
pucAlignedHeap = ( uint8_t * ) uxAddress;
/* 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;
/* pxEnd is used to mark the end of the list of free blocks and is inserted
* at the end of the heap space. */
uxAddress = ( portPOINTER_SIZE_TYPE ) ( pucAlignedHeap + xTotalHeapSize );
uxAddress -= xHeapStructSize;
uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
pxEnd = ( BlockLink_t * ) uxAddress;
pxEnd->xBlockSize = 0;
pxEnd->pxNextFreeBlock = NULL;
/* To start with there is a single free block that is sized to take up the
* entire heap space, minus the space taken by pxEnd. */
pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap;
pxFirstFreeBlock->xBlockSize = ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlock );
pxFirstFreeBlock->pxNextFreeBlock = pxEnd;
/* Only one block exists - and it covers the entire usable heap space. */
xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
}
/*-----------------------------------------------------------*/
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVILEGED_FUNCTION */
{
BlockLink_t * pxIterator;
uint8_t * puc;
/* Iterate through the list until a block is found that has a higher address
* than the block being inserted. */
for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )
{
/* Nothing to do here, just iterate to the right position. */
}
/* Do the block being inserted, and the block it is being inserted after
* make a contiguous block of memory? */
puc = ( uint8_t * ) pxIterator;
if( ( puc + pxIterator->xBlockSize ) == ( uint8_t * ) pxBlockToInsert )
{
pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
pxBlockToInsert = pxIterator;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
/* Do the block being inserted, and the block it is being inserted before
* make a contiguous block of memory? */
puc = ( uint8_t * ) pxBlockToInsert;
if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock )
{
if( pxIterator->pxNextFreeBlock != pxEnd )
{
/* Form one big block from the two blocks. */
pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
}
else
{
pxBlockToInsert->pxNextFreeBlock = pxEnd;
}
}
else
{
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
}
/* If the block being inserted plugged a gab, so was merged with the block
* before and the block after, then it's pxNextFreeBlock pointer will have
* already been set, and should not be set here as that would make it point
* to itself. */
if( pxIterator != pxBlockToInsert )
{
pxIterator->pxNextFreeBlock = pxBlockToInsert;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
/*-----------------------------------------------------------*/
void vPortGetHeapStats( HeapStats_t * pxHeapStats )
{
BlockLink_t * pxBlock;
size_t xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */
vTaskSuspendAll();
{
pxBlock = xStart.pxNextFreeBlock;
/* pxBlock will be NULL if the heap has not been initialised. The heap
* is initialised automatically when the first allocation is made. */
if( pxBlock != NULL )
{
while( pxBlock != pxEnd )
{
/* Increment the number of blocks and record the largest block seen
* so far. */
xBlocks++;
if( pxBlock->xBlockSize > xMaxSize )
{
xMaxSize = pxBlock->xBlockSize;
}
if( pxBlock->xBlockSize < xMinSize )
{
xMinSize = pxBlock->xBlockSize;
}
/* Move to the next block in the chain until the last block is
* reached. */
pxBlock = pxBlock->pxNextFreeBlock;
}
}
}
( void ) xTaskResumeAll();
pxHeapStats->xSizeOfLargestFreeBlockInBytes = xMaxSize;
pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;
pxHeapStats->xNumberOfFreeBlocks = xBlocks;
taskENTER_CRITICAL();
{
pxHeapStats->xAvailableHeapSpaceInBytes = xFreeBytesRemaining;
pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;
pxHeapStats->xNumberOfSuccessfulFrees = xNumberOfSuccessfulFrees;
pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;
}
taskEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/