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/*
* FreeRTOS memory safety proofs with CBMC.
* 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://aws.amazon.com/freertos
* http://www.FreeRTOS.org
*/
#include "cbmc.h"
/*
* We allocate a TCB and set some members to basic values
*/
TaskHandle_t xUnconstrainedTCB( void )
{
TCB_t * pxTCB = pvPortMalloc(sizeof(TCB_t));
if ( pxTCB == NULL )
return NULL;
__CPROVER_assume( pxTCB->uxPriority < configMAX_PRIORITIES );
vListInitialiseItem( &( pxTCB->xStateListItem ) );
vListInitialiseItem( &( pxTCB->xEventListItem ) );
listSET_LIST_ITEM_OWNER( &( pxTCB->xStateListItem ), pxTCB );
listSET_LIST_ITEM_OWNER( &( pxTCB->xEventListItem ), pxTCB );
if ( nondet_bool() )
{
listSET_LIST_ITEM_VALUE( &( pxTCB->xStateListItem ), pxTCB->uxPriority );
}
else
{
listSET_LIST_ITEM_VALUE( &( pxTCB->xStateListItem ), portMAX_DELAY );
}
if ( nondet_bool() )
{
listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), ( TickType_t ) configMAX_PRIORITIES - ( TickType_t ) pxTCB->uxPriority );
}
else
{
listSET_LIST_ITEM_VALUE( &( pxTCB->xEventListItem ), portMAX_DELAY );
}
return pxTCB;
}
/*
* We set the values of relevant global variables to
* nondeterministic values, except for `uxSchedulerSuspended`
* which is set to 0 (to pass through the assertion)
*/
void vSetGlobalVariables( void )
{
uxSchedulerSuspended = pdFALSE;
xTickCount = nondet_ticktype();
xNextTaskUnblockTime = nondet_ticktype();
}
/*
* We initialise and fill the task lists so coverage is optimal.
* This initialization is not guaranteed to be minimal, but it
* is quite efficient and it serves the same purpose
*/
BaseType_t xPrepareTaskLists( void )
{
TCB_t * pxTCB = NULL;
__CPROVER_assert_zero_allocation();
prvInitialiseTaskLists();
/* The current task will be moved to the delayed list */
pxCurrentTCB = xUnconstrainedTCB();
if ( pxCurrentTCB == NULL )
{
return pdFAIL;
}
vListInsert( &pxReadyTasksLists[ pxCurrentTCB->uxPriority ], &( pxCurrentTCB->xStateListItem ) );
/*
* Nondeterministic insertion of a task in the ready tasks list
* guarantees coverage in line 5104 (tasks.c)
*/
if ( nondet_bool() )
{
pxTCB = xUnconstrainedTCB();
if ( pxTCB == NULL )
{
return pdFAIL;
}
vListInsert( &pxReadyTasksLists[ pxTCB->uxPriority ], &( pxTCB->xStateListItem ) );
/* Use of this macro ensures coverage on line 185 (list.c) */
listGET_OWNER_OF_NEXT_ENTRY( pxTCB , &pxReadyTasksLists[ pxTCB->uxPriority ] );
}
return pdPASS;
}
/*
* We stub out `xTaskResumeAll` including the assertion and change on
* variables `uxSchedulerSuspended`. We assume that `xPendingReadyList`
* is empty to avoid the first loop, and xPendedTicks to avoid the second
* one. Finally, we return a nondeterministic value (overapproximation)
*/
BaseType_t xTaskResumeAllStub( void )
{
BaseType_t xAlreadyYielded;
configASSERT( uxSchedulerSuspended );
taskENTER_CRITICAL();
{
--uxSchedulerSuspended;
__CPROVER_assert( listLIST_IS_EMPTY( &xPendingReadyList ), "Pending ready tasks list not empty." );
__CPROVER_assert( xPendedTicks == 0 , "xPendedTicks is not equal to zero.");
}
taskEXIT_CRITICAL();
return xAlreadyYielded;
}
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