Suppress MISRA C rule 11.3 in MISRA.md (#857)

Suppress MISRA C rule 11.3 in MISRA.md

MISRA.md

@@ -31,6 +31,25 @@ _Ref 8.4.1_
         a declaration in header file is not useful as the assembly code will
         still need to declare it separately.
 
+
+#### Rule 11.3
+
+_Ref 11.3.1_
+
+- MISRA C:2012 Rule 11.3: A cast shall not be performed between a pointer to
+        object type and a pointer to a different object type.
+        This rule prohibits casting a pointer to object into a pointer to a
+        different object because it may result in an incorrectly aligned pointer,
+        leading to undefined behavior. Even if the casting produces a correctly
+        aligned pointer, the behavior may be still undefined if the pointer is
+        used to access an object. FreeRTOS deliberately creates external aliases
+        for all the kernel object types (StaticEventGroup_t, StaticQueue_t,
+        StaticStreamBuffer_t, StaticTimer_t and StaticTask_t) for data hiding
+        purposes. The internal object types and the corresponding external
+        aliases are guaranteed to have the same size and alignment which is
+        checked using configASSERT.
+
+
 ### MISRA configuration
 
 Copy below content to `misra.conf` to run Coverity on FreeRTOS-Kernel.

event_groups.c

@@ -98,7 +98,10 @@ static BaseType_t prvTestWaitCondition( const EventBits_t uxCurrentEventBits,
         #endif /* configASSERT_DEFINED */
 
         /* The user has provided a statically allocated event group - use it. */
-        pxEventBits = ( EventGroup_t * ) pxEventGroupBuffer; /*lint !e740 !e9087 EventGroup_t and StaticEventGroup_t are deliberately aliased for data hiding purposes and guaranteed to have the same size and alignment requirement - checked by configASSERT(). */
+        /* MISRA Ref 11.3.1 [Misaligned access] */
+        /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+        /* coverity[misra_c_2012_rule_11_3_violation] */
+        pxEventBits = ( EventGroup_t * ) pxEventGroupBuffer;
 
         if( pxEventBits != NULL )
         {
@@ -710,6 +713,9 @@ void vEventGroupDelete( EventGroupHandle_t xEventGroup )
             /* Check if the event group was statically allocated. */
             if( pxEventBits->ucStaticallyAllocated == ( uint8_t ) pdTRUE )
             {
+                /* MISRA Ref 11.3.1 [Misaligned access] */
+                /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+                /* coverity[misra_c_2012_rule_11_3_violation] */
                 *ppxEventGroupBuffer = ( StaticEventGroup_t * ) pxEventBits;
                 xReturn = pdTRUE;
             }
@@ -721,6 +727,9 @@ void vEventGroupDelete( EventGroupHandle_t xEventGroup )
         #else /* configSUPPORT_DYNAMIC_ALLOCATION */
         {
             /* Event group must have been statically allocated. */
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
             *ppxEventGroupBuffer = ( StaticEventGroup_t * ) pxEventBits;
             xReturn = pdTRUE;
         }

queue.c

@@ -408,7 +408,10 @@ BaseType_t xQueueGenericReset( QueueHandle_t xQueue,
             /* The address of a statically allocated queue was passed in, use it.
              * The address of a statically allocated storage area was also passed in
              * but is already set. */
-            pxNewQueue = ( Queue_t * ) pxStaticQueue; /*lint !e740 !e9087 Unusual cast is ok as the structures are designed to have the same alignment, and the size is checked by an assert. */
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
+            pxNewQueue = ( Queue_t * ) pxStaticQueue;
 
             #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
             {
@@ -459,6 +462,9 @@ BaseType_t xQueueGenericReset( QueueHandle_t xQueue,
                     *ppucQueueStorage = ( uint8_t * ) pxQueue->pcHead;
                 }
 
+                /* MISRA Ref 11.3.1 [Misaligned access] */
+                /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+                /* coverity[misra_c_2012_rule_11_3_violation] */
                 *ppxStaticQueue = ( StaticQueue_t * ) pxQueue;
                 xReturn = pdTRUE;
             }

stream_buffer.c

@@ -406,7 +406,10 @@ static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
                                                            StreamBufferCallbackFunction_t pxSendCompletedCallback,
                                                            StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
     {
-        StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer; /*lint !e740 !e9087 Safe cast as StaticStreamBuffer_t is opaque Streambuffer_t. */
+        /* MISRA Ref 11.3.1 [Misaligned access] */
+        /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+        /* coverity[misra_c_2012_rule_11_3_violation] */
+        StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer;
         StreamBufferHandle_t xReturn;
         uint8_t ucFlags;
 
@@ -466,7 +469,10 @@ static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
 
             traceSTREAM_BUFFER_CREATE( pxStreamBuffer, xIsMessageBuffer );
 
-            xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer; /*lint !e9087 Data hiding requires cast to opaque type. */
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
+            xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer;
         }
         else
         {
@@ -498,6 +504,9 @@ static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
         if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) != ( uint8_t ) 0 )
         {
             *ppucStreamBufferStorageArea = pxStreamBuffer->pucBuffer;
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
             *ppxStaticStreamBuffer = ( StaticStreamBuffer_t * ) pxStreamBuffer;
             xReturn = pdTRUE;
         }

tasks.c

@@ -1271,7 +1271,10 @@ static void prvAddNewTaskToReadyList( TCB_t * pxNewTCB ) PRIVILEGED_FUNCTION;
         {
             /* The memory used for the task's TCB and stack are passed into this
              * function - use them. */
-            pxNewTCB = ( TCB_t * ) pxTaskBuffer; /*lint !e740 !e9087 Unusual cast is ok as the structures are designed to have the same alignment, and the size is checked by an assert. */
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
+            pxNewTCB = ( TCB_t * ) pxTaskBuffer;
             ( void ) memset( ( void * ) pxNewTCB, 0x00, sizeof( TCB_t ) );
             pxNewTCB->pxStack = ( StackType_t * ) puxStackBuffer;
 
@@ -4354,6 +4357,9 @@ char * pcTaskGetName( TaskHandle_t xTaskToQuery ) /*lint !e971 Unqualified char
             if( pxTCB->ucStaticallyAllocated == tskSTATICALLY_ALLOCATED_STACK_AND_TCB )
             {
                 *ppuxStackBuffer = pxTCB->pxStack;
+                /* MISRA Ref 11.3.1 [Misaligned access] */
+                /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+                /* coverity[misra_c_2012_rule_11_3_violation] */
                 *ppxTaskBuffer = ( StaticTask_t * ) pxTCB;
                 xReturn = pdTRUE;
             }

timers.c

@@ -394,7 +394,10 @@
 
             /* A pointer to a StaticTimer_t structure MUST be provided, use it. */
             configASSERT( pxTimerBuffer );
-            pxNewTimer = ( Timer_t * ) pxTimerBuffer; /*lint !e740 !e9087 StaticTimer_t is a pointer to a Timer_t, so guaranteed to be aligned and sized correctly (checked by an assert()), so this is safe. */
+            /* MISRA Ref 11.3.1 [Misaligned access] */
+            /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+            /* coverity[misra_c_2012_rule_11_3_violation] */
+            pxNewTimer = ( Timer_t * ) pxTimerBuffer;
 
             if( pxNewTimer != NULL )
             {
@@ -664,6 +667,9 @@
 
             if( ( pxTimer->ucStatus & tmrSTATUS_IS_STATICALLY_ALLOCATED ) != 0U )
             {
+                /* MISRA Ref 11.3.1 [Misaligned access] */
+                /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
+                /* coverity[misra_c_2012_rule_11_3_violation] */
                 *ppxTimerBuffer = ( StaticTimer_t * ) pxTimer;
                 xReturn = pdTRUE;
             }