FreeRTOS-RISCV/FreeRTOSv10.2.1/FreeRTOS/Source/portable/MemMang/heap_2.c

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2019-06-28 23:08:36 +02:00
/*
* FreeRTOS Kernel V10.2.1
* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/*
* 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 http://www.FreeRTOS.org for more information.
*/
#include <stdlib.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
/* A few bytes might be lost to byte aligning the heap start address. */
#define configADJUSTED_HEAP_SIZE ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )
/*
* Initialises the heap structures before their first use.
*/
static void prvHeapInit( void );
/* 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
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 ) ) & ~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. */
static BlockLink_t xStart, xEnd;
/* Keeps track of the number of free bytes remaining, but says nothing about
fragmentation. */
static size_t xFreeBytesRemaining = configADJUSTED_HEAP_SIZE;
/* 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, *pxPreviousBlock, *pxNewBlockLink;
static BaseType_t xHeapHasBeenInitialised = pdFALSE;
void *pvReturn = NULL;
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;
}
/* The wanted size is increased so it can contain a BlockLink_t
structure in addition to the requested amount of bytes. */
if( xWantedSize > 0 )
{
xWantedSize += heapSTRUCT_SIZE;
/* Ensure that blocks are always aligned to the required number of bytes. */
if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0 )
{
/* Byte alignment required. */
xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
}
}
if( ( xWantedSize > 0 ) && ( xWantedSize < configADJUSTED_HEAP_SIZE ) )
{
/* 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;
}
}
traceMALLOC( pvReturn, xWantedSize );
}
( void ) xTaskResumeAll();
#if( configUSE_MALLOC_FAILED_HOOK == 1 )
{
if( pvReturn == NULL )
{
extern void vApplicationMallocFailedHook( void );
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;
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. */
}
/*-----------------------------------------------------------*/
static void prvHeapInit( void )
{
BlockLink_t *pxFirstFreeBlock;
uint8_t *pucAlignedHeap;
/* Ensure the heap starts on a correctly aligned boundary. */
pucAlignedHeap = ( uint8_t * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ portBYTE_ALIGNMENT ] ) & ( ~( ( 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 = ( void * ) pucAlignedHeap;
pxFirstFreeBlock->xBlockSize = configADJUSTED_HEAP_SIZE;
pxFirstFreeBlock->pxNextFreeBlock = &xEnd;
}
/*-----------------------------------------------------------*/