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Heap improvements (#462)

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* Heap improvements

This commit makes the following improvements:

1. Add a check to heap_2 to track if a memory block is allocated to the
   application or not. The MSB of the size field is used for this
   purpose. The same check already exists in heap_4 and heap_5. This
   check prevents against double free.

2. Add a new flag configHEAP_CLEAR_MEMORY_ON_FREE to heap_2, heap_4 and
   heap_5. The application writer can set it to 1 in their
   FreeRTOSConfig.h to ensure that a block of memory allocated using
   pvPortMalloc is cleared (i.e. set to zero) when it is freed using
   vPortFree. If left undefined, configHEAP_CLEAR_MEMORY_ON_FREE
   defaults to 0 for backward compatibility. We recommend setting
   configHEAP_CLEAR_MEMORY_ON_FREE to 1 for better security.

3. Add a new API pvPortCalloc to heap_2, heap_4 and heap_5. This API
   has the following signature:
   void * pvPortCalloc( size_t xNum, size_t xSize );
   It allocates memory for an array of xNum objects each of which is of
   xSize and initializes all bytes in the allocated storage to zero. If
   allocation succeeds, it returns a pointer to the lowest byte in the
   allocated memory block. On failure, it returns a null pointer.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
This commit is contained in:
Gaurav-Aggarwal-AWS 2022-02-24 10:52:10 -08:00 committed by GitHub
parent 4539e1c574
commit 82be77995e
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
4 changed files with 249 additions and 98 deletions
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2
include/portable.h
View file

@ -173,6 +173,8 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats );
* Map to the memory management routines required for the port. * Map to the memory management routines required for the port.
*/ */
void * pvPortMalloc( size_t xSize ) PRIVILEGED_FUNCTION; void * pvPortMalloc( size_t xSize ) PRIVILEGED_FUNCTION;
void * pvPortCalloc( size_t xNum,
size_t xSize ) PRIVILEGED_FUNCTION;
void vPortFree( void * pv ) PRIVILEGED_FUNCTION; void vPortFree( void * pv ) PRIVILEGED_FUNCTION;
void vPortInitialiseBlocks( void ) PRIVILEGED_FUNCTION; void vPortInitialiseBlocks( void ) PRIVILEGED_FUNCTION;
size_t xPortGetFreeHeapSize( void ) PRIVILEGED_FUNCTION; size_t xPortGetFreeHeapSize( void ) PRIVILEGED_FUNCTION;

213
portable/MemMang/heap_2.c
View file

@ -36,6 +36,7 @@
* memory management pages of https://www.FreeRTOS.org for more information. * memory management pages of https://www.FreeRTOS.org for more information.
*/ */
#include <stdlib.h> #include <stdlib.h>
#include <string.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining /* 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 * all the API functions to use the MPU wrappers. That should only be done when
@ -51,13 +52,30 @@
#error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0 #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
#endif #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. */ /* A few bytes might be lost to byte aligning the heap start address. */
#define configADJUSTED_HEAP_SIZE ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT ) #define configADJUSTED_HEAP_SIZE ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )
/* /* Assumes 8bit bytes! */
* Initialises the heap structures before their first use. #define heapBITS_PER_BYTE ( ( size_t ) 8 )
*/
static void prvHeapInit( void ); /* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW( a, b, max ) ( ( ( a ) > 0 ) && ( ( b ) > ( ( max ) / ( a ) ) ) )
/* 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. */ /* Allocate the memory for the heap. */
#if ( configAPPLICATION_ALLOCATED_HEAP == 1 ) #if ( configAPPLICATION_ALLOCATED_HEAP == 1 )
@ -66,7 +84,7 @@ static void prvHeapInit( void );
* heap - probably so it can be placed in a special segment or address. */ * heap - probably so it can be placed in a special segment or address. */
extern uint8_t ucHeap[ configTOTAL_HEAP_SIZE ]; extern uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
#else #else
static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ]; PRIVILEGED_DATA static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
#endif /* configAPPLICATION_ALLOCATED_HEAP */ #endif /* configAPPLICATION_ALLOCATED_HEAP */
@ -83,11 +101,20 @@ static const uint16_t heapSTRUCT_SIZE = ( ( sizeof( BlockLink_t ) + ( portBYTE_A
#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) ) #define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) )
/* Create a couple of list links to mark the start and end of the list. */ /* Create a couple of list links to mark the start and end of the list. */
static BlockLink_t xStart, xEnd; PRIVILEGED_DATA static BlockLink_t xStart, xEnd;
/* Keeps track of the number of free bytes remaining, but says nothing about /* Keeps track of the number of free bytes remaining, but says nothing about
* fragmentation. */ * fragmentation. */
static size_t xFreeBytesRemaining = configADJUSTED_HEAP_SIZE; 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. */ /* STATIC FUNCTIONS ARE DEFINED AS MACROS TO MINIMIZE THE FUNCTION CALL DEPTH. */
@ -120,7 +147,7 @@ static size_t xFreeBytesRemaining = configADJUSTED_HEAP_SIZE;
void * pvPortMalloc( size_t xWantedSize ) void * pvPortMalloc( size_t xWantedSize )
{ {
BlockLink_t * pxBlock, * pxPreviousBlock, * pxNewBlockLink; BlockLink_t * pxBlock, * pxPreviousBlock, * pxNewBlockLink;
static BaseType_t xHeapHasBeenInitialised = pdFALSE; PRIVILEGED_DATA static BaseType_t xHeapHasBeenInitialised = pdFALSE;
void * pvReturn = NULL; void * pvReturn = NULL;
vTaskSuspendAll(); vTaskSuspendAll();
@ -133,72 +160,84 @@ void * pvPortMalloc( size_t xWantedSize )
xHeapHasBeenInitialised = pdTRUE; xHeapHasBeenInitialised = pdTRUE;
} }
/* The wanted size must be increased so it can contain a BlockLink_t /* Check the requested block size is not so large that the top bit is
* structure in addition to the requested amount of bytes. */ * set. The top bit of the block size member of the BlockLink_t structure
if( ( xWantedSize > 0 ) && * is used to determine who owns the block - the application or the
( ( xWantedSize + heapSTRUCT_SIZE ) > xWantedSize ) ) /* Overflow check */ * kernel, so it must be free. */
if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) )
{ {
xWantedSize += heapSTRUCT_SIZE; /* The wanted size must be increased so it can contain a BlockLink_t
* structure in addition to the requested amount of bytes. */
/* Byte alignment required. Check for overflow. */ if( ( xWantedSize > 0 ) &&
if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) ( ( xWantedSize + heapSTRUCT_SIZE ) > xWantedSize ) ) /* Overflow check */
> xWantedSize )
{ {
xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); xWantedSize += heapSTRUCT_SIZE;
configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 );
/* Byte alignment required. Check for overflow. */
if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) )
> xWantedSize )
{
xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 );
}
else
{
xWantedSize = 0;
}
} }
else else
{ {
xWantedSize = 0; xWantedSize = 0;
} }
}
else
{
xWantedSize = 0;
}
if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) ) 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; /* Blocks are stored in byte order - traverse the list from the start
pxBlock = pxBlock->pxNextFreeBlock; * (smallest) block until one of adequate size is found. */
} pxPreviousBlock = &xStart;
pxBlock = xStart.pxNextFreeBlock;
/* If we found the end marker then a block of adequate size was not found. */ while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )
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 pxPreviousBlock = pxBlock;
* following the number of bytes requested. The void cast is pxBlock = pxBlock->pxNextFreeBlock;
* 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; /* 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;
}
} }
} }
@ -235,14 +274,32 @@ void vPortFree( void * pv )
* byte alignment warnings. */ * byte alignment warnings. */
pxLink = ( void * ) puc; pxLink = ( void * ) puc;
vTaskSuspendAll(); configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) );
configASSERT( pxLink->pxNextFreeBlock == NULL );
if( heapBLOCK_IS_ALLOCATED( pxLink ) )
{ {
/* Add this block to the list of free blocks. */ if( pxLink->pxNextFreeBlock == NULL )
prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) ); {
xFreeBytesRemaining += pxLink->xBlockSize; /* The block is being returned to the heap - it is no longer
traceFREE( pv, pxLink->xBlockSize ); * 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();
}
} }
( void ) xTaskResumeAll();
} }
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
@ -259,7 +316,27 @@ void vPortInitialiseBlocks( void )
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
static void prvHeapInit( void ) void * pvPortCalloc( size_t xNum,
size_t xSize )
{
void * pv = NULL;
const size_t xSizeMaxValue = ~( ( size_t ) 0 );
if( !heapMULTIPLY_WILL_OVERFLOW( xNum, xSize, xSizeMaxValue ) )
{
pv = pvPortMalloc( xNum * xSize );
if( pv != NULL )
{
( void ) memset( pv, 0, xNum * xSize );
}
}
return pv;
}
/*-----------------------------------------------------------*/
static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
{ {
BlockLink_t * pxFirstFreeBlock; BlockLink_t * pxFirstFreeBlock;
uint8_t * pucAlignedHeap; uint8_t * pucAlignedHeap;

66
portable/MemMang/heap_4.c
View file

@ -35,6 +35,7 @@
* memory management pages of https://www.FreeRTOS.org for more information. * memory management pages of https://www.FreeRTOS.org for more information.
*/ */
#include <stdlib.h> #include <stdlib.h>
#include <string.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining /* 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 * all the API functions to use the MPU wrappers. That should only be done when
@ -50,12 +51,31 @@
#error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0 #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
#endif #endif
#ifndef configHEAP_CLEAR_MEMORY_ON_FREE
#define configHEAP_CLEAR_MEMORY_ON_FREE 0
#endif
/* Block sizes must not get too small. */ /* Block sizes must not get too small. */
#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) ) #define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
/* Assumes 8bit bytes! */ /* Assumes 8bit bytes! */
#define heapBITS_PER_BYTE ( ( size_t ) 8 ) #define heapBITS_PER_BYTE ( ( size_t ) 8 )
/* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW( a, b, max ) ( ( ( a ) > 0 ) && ( ( b ) > ( ( max ) / ( a ) ) ) )
/* 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. */ /* Allocate the memory for the heap. */
#if ( configAPPLICATION_ALLOCATED_HEAP == 1 ) #if ( configAPPLICATION_ALLOCATED_HEAP == 1 )
@ -106,12 +126,6 @@ PRIVILEGED_DATA static size_t xMinimumEverFreeBytesRemaining = 0U;
PRIVILEGED_DATA static size_t xNumberOfSuccessfulAllocations = 0; PRIVILEGED_DATA static size_t xNumberOfSuccessfulAllocations = 0;
PRIVILEGED_DATA static size_t xNumberOfSuccessfulFrees = 0; PRIVILEGED_DATA static size_t xNumberOfSuccessfulFrees = 0;
/* Gets set to the top bit of an size_t type. When this bit in 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. */
PRIVILEGED_DATA static size_t xBlockAllocatedBit = 0;
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
void * pvPortMalloc( size_t xWantedSize ) void * pvPortMalloc( size_t xWantedSize )
@ -136,7 +150,7 @@ void * pvPortMalloc( size_t xWantedSize )
* set. The top bit of the block size member of the BlockLink_t structure * 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 * is used to determine who owns the block - the application or the
* kernel, so it must be free. */ * kernel, so it must be free. */
if( ( xWantedSize & xBlockAllocatedBit ) == 0 ) if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) )
{ {
/* The wanted size must be increased so it can contain a BlockLink_t /* The wanted size must be increased so it can contain a BlockLink_t
* structure in addition to the requested amount of bytes. */ * structure in addition to the requested amount of bytes. */
@ -232,7 +246,7 @@ void * pvPortMalloc( size_t xWantedSize )
/* The block is being returned - it is allocated and owned /* The block is being returned - it is allocated and owned
* by the application and has no "next" block. */ * by the application and has no "next" block. */
pxBlock->xBlockSize |= xBlockAllocatedBit; heapALLOCATE_BLOCK( pxBlock );
pxBlock->pxNextFreeBlock = NULL; pxBlock->pxNextFreeBlock = NULL;
xNumberOfSuccessfulAllocations++; xNumberOfSuccessfulAllocations++;
} }
@ -288,17 +302,21 @@ void vPortFree( void * pv )
/* This casting is to keep the compiler from issuing warnings. */ /* This casting is to keep the compiler from issuing warnings. */
pxLink = ( void * ) puc; pxLink = ( void * ) puc;
/* Check the block is actually allocated. */ configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) );
configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );
configASSERT( pxLink->pxNextFreeBlock == NULL ); configASSERT( pxLink->pxNextFreeBlock == NULL );
if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 ) if( heapBLOCK_IS_ALLOCATED( pxLink ) )
{ {
if( pxLink->pxNextFreeBlock == NULL ) if( pxLink->pxNextFreeBlock == NULL )
{ {
/* The block is being returned to the heap - it is no longer /* The block is being returned to the heap - it is no longer
* allocated. */ * allocated. */
pxLink->xBlockSize &= ~xBlockAllocatedBit; heapFREE_BLOCK( pxLink );
#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
{
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
}
#endif
vTaskSuspendAll(); vTaskSuspendAll();
{ {
@ -341,6 +359,26 @@ void vPortInitialiseBlocks( void )
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
void * pvPortCalloc( size_t xNum,
size_t xSize )
{
void * pv = NULL;
const size_t xSizeMaxValue = ~( ( size_t ) 0 );
if( !heapMULTIPLY_WILL_OVERFLOW( xNum, xSize, xSizeMaxValue ) )
{
pv = pvPortMalloc( xNum * xSize );
if( pv != NULL )
{
( void ) memset( pv, 0, xNum * xSize );
}
}
return pv;
}
/*-----------------------------------------------------------*/
static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
{ {
BlockLink_t * pxFirstFreeBlock; BlockLink_t * pxFirstFreeBlock;
@ -383,9 +421,6 @@ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
/* Only one block exists - and it covers the entire usable heap space. */ /* Only one block exists - and it covers the entire usable heap space. */
xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize; xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize; xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
/* Work out the position of the top bit in a size_t variable. */
xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
@ -502,3 +537,4 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
} }
taskEXIT_CRITICAL(); taskEXIT_CRITICAL();
} }
/*-----------------------------------------------------------*/

66
portable/MemMang/heap_5.c
View file

@ -69,6 +69,7 @@
* *
*/ */
#include <stdlib.h> #include <stdlib.h>
#include <string.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining /* 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 * all the API functions to use the MPU wrappers. That should only be done when
@ -84,12 +85,31 @@
#error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0 #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
#endif #endif
#ifndef configHEAP_CLEAR_MEMORY_ON_FREE
#define configHEAP_CLEAR_MEMORY_ON_FREE 0
#endif
/* Block sizes must not get too small. */ /* Block sizes must not get too small. */
#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) ) #define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
/* Assumes 8bit bytes! */ /* Assumes 8bit bytes! */
#define heapBITS_PER_BYTE ( ( size_t ) 8 ) #define heapBITS_PER_BYTE ( ( size_t ) 8 )
/* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW( a, b, max ) ( ( ( a ) > 0 ) && ( ( b ) > ( ( max ) / ( a ) ) ) )
/* 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 )
/*-----------------------------------------------------------*/
/* Define the linked list structure. This is used to link free blocks in order /* Define the linked list structure. This is used to link free blocks in order
* of their memory address. */ * of their memory address. */
typedef struct A_BLOCK_LINK typedef struct A_BLOCK_LINK
@ -124,12 +144,6 @@ static size_t xMinimumEverFreeBytesRemaining = 0U;
static size_t xNumberOfSuccessfulAllocations = 0; static size_t xNumberOfSuccessfulAllocations = 0;
static size_t xNumberOfSuccessfulFrees = 0; static size_t xNumberOfSuccessfulFrees = 0;
/* Gets set to the top bit of an size_t type. When this bit in 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. */
static size_t xBlockAllocatedBit = 0;
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
void * pvPortMalloc( size_t xWantedSize ) void * pvPortMalloc( size_t xWantedSize )
@ -147,7 +161,7 @@ void * pvPortMalloc( size_t xWantedSize )
* set. The top bit of the block size member of the BlockLink_t structure * 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 * is used to determine who owns the block - the application or the
* kernel, so it must be free. */ * kernel, so it must be free. */
if( ( xWantedSize & xBlockAllocatedBit ) == 0 ) if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) )
{ {
/* The wanted size is increased so it can contain a BlockLink_t /* The wanted size is increased so it can contain a BlockLink_t
* structure in addition to the requested amount of bytes. */ * structure in addition to the requested amount of bytes. */
@ -241,7 +255,7 @@ void * pvPortMalloc( size_t xWantedSize )
/* The block is being returned - it is allocated and owned /* The block is being returned - it is allocated and owned
* by the application and has no "next" block. */ * by the application and has no "next" block. */
pxBlock->xBlockSize |= xBlockAllocatedBit; heapALLOCATE_BLOCK( pxBlock );
pxBlock->pxNextFreeBlock = NULL; pxBlock->pxNextFreeBlock = NULL;
xNumberOfSuccessfulAllocations++; xNumberOfSuccessfulAllocations++;
} }
@ -296,17 +310,21 @@ void vPortFree( void * pv )
/* This casting is to keep the compiler from issuing warnings. */ /* This casting is to keep the compiler from issuing warnings. */
pxLink = ( void * ) puc; pxLink = ( void * ) puc;
/* Check the block is actually allocated. */ configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) );
configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );
configASSERT( pxLink->pxNextFreeBlock == NULL ); configASSERT( pxLink->pxNextFreeBlock == NULL );
if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 ) if( heapBLOCK_IS_ALLOCATED( pxLink ) )
{ {
if( pxLink->pxNextFreeBlock == NULL ) if( pxLink->pxNextFreeBlock == NULL )
{ {
/* The block is being returned to the heap - it is no longer /* The block is being returned to the heap - it is no longer
* allocated. */ * allocated. */
pxLink->xBlockSize &= ~xBlockAllocatedBit; heapFREE_BLOCK( pxLink );
#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
{
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
}
#endif
vTaskSuspendAll(); vTaskSuspendAll();
{ {
@ -343,6 +361,26 @@ size_t xPortGetMinimumEverFreeHeapSize( void )
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
void * pvPortCalloc( size_t xNum,
size_t xSize )
{
void * pv = NULL;
const size_t xSizeMaxValue = ~( ( size_t ) 0 );
if( !heapMULTIPLY_WILL_OVERFLOW( xNum, xSize, xSizeMaxValue ) )
{
pv = pvPortMalloc( xNum * xSize );
if( pv != NULL )
{
( void ) memset( pv, 0, xNum * xSize );
}
}
return pv;
}
/*-----------------------------------------------------------*/
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert )
{ {
BlockLink_t * pxIterator; BlockLink_t * pxIterator;
@ -495,9 +533,6 @@ void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions )
/* Check something was actually defined before it is accessed. */ /* Check something was actually defined before it is accessed. */
configASSERT( xTotalHeapSize ); configASSERT( xTotalHeapSize );
/* Work out the position of the top bit in a size_t variable. */
xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
@ -557,3 +592,4 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
} }
taskEXIT_CRITICAL(); taskEXIT_CRITICAL();
} }
/*-----------------------------------------------------------*/