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Refined lock invariant to only give read permission to all tasks and write permission to locally scheduled task

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This commit is contained in:
Tobias Reinhard 2022-12-03 08:58:19 -05:00
parent 1919f8142f
commit e4db1f8aba
3 changed files with 22 additions and 9 deletions
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14
tasks.c
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@ -1051,7 +1051,12 @@ static void prvYieldForTask( TCB_t * pxTCB,
mem(pxTaskItem, gCells) == true &*&
xLIST(gReadyList, gSize, gIndex, gEnd, gCells, gVals, gOwners) &*&
gSize > 0 &*&
foreach(gTasks, sharedSeg_TCB_p) &*&
// Read permissions for every task
foreach(gTasks, readOnly_sharedSeg_TCB_p)
&*&
// Write permission for task scheduled on this core
[1/2]sharedSeg_TCB_p(gCurrentTCB)
&*&
subset(gOwners, gTasks) == true;
@*/
@ -1129,7 +1134,7 @@ static void prvYieldForTask( TCB_t * pxTCB,
#endif
#endif
{
//@ assert( foreach(remove(pxTCB, gTasks), sharedSeg_TCB_p) );
//@ assert( foreach(remove(pxTCB, gTasks), readOnly_sharedSeg_TCB_p) );
//@ assert( gCurrentTCB == pxCurrentTCBs[ xCoreID ] );
/*@
if( gCurrentTCB == pxTCB ) {
@ -1138,7 +1143,6 @@ static void prvYieldForTask( TCB_t * pxTCB,
} else {
neq_mem_remove(gCurrentTCB, pxTCB, gTasks);
foreach_remove(gCurrentTCB, remove(pxTCB, gTasks));
open sharedSeg_TCB_p(gCurrentTCB);
}
@*/
/* If the task is not being executed by any core swap it in */
@ -1157,13 +1161,14 @@ static void prvYieldForTask( TCB_t * pxTCB,
// => We don't have to close anything.
} else {
close sharedSeg_TCB_p(gCurrentTCB);
close readOnly_sharedSeg_TCB_p(gCurrentTCB);
foreach_unremove(gCurrentTCB, remove(pxTCB, gTasks));
}
@*/
// Ensure we restored the collection as it was
// at the beginning of the block.
//@ assert( foreach(remove(pxTCB, gTasks), sharedSeg_TCB_p) );
//@ assert( foreach(remove(pxTCB, gTasks), readOnly_sharedSeg_TCB_p) );
}
}
else if( pxTCB == pxCurrentTCBs[ xCoreID ] )
@ -1196,6 +1201,7 @@ static void prvYieldForTask( TCB_t * pxTCB,
}
//@ close sharedSeg_TCB_p(pxTCB);
//@ close readOnly_sharedSeg_TCB(pxTCB);
//@ foreach_unremove(pxTCB, gTasks);
} while( pxTaskItem != pxLastTaskItem );

4
verification/verifast/proof/task_predicates.h
View file

@ -111,6 +111,10 @@ predicate prvSeg_TCB_p(TCB_t* tcb, uint32_t ulFreeBytesOnStack) =
predicate sharedSeg_TCB_p(TCB_t* tcb;) =
tcb->xTaskRunState |-> ?gTaskRunState;
// Auxiliary predicate to allow foreach-quantification about fraction
predicate readOnly_sharedSeg_TCB_p(TCB_t* tcb;) =
[1/2]sharedSeg_TCB_p(tcb);
predicate coreLocalSeg_TCB_p(TCB_t* tcb, UBaseType_t uxCriticalNesting) =
tcb->uxCriticalNesting |-> uxCriticalNesting;
@*/

11
verification/verifast/proof/verifast_lock_predicates.h
View file

@ -97,10 +97,13 @@ predicate taskISRLockInv_p() =
// tasks / TCBs
exists_in_taskISRLockInv_p(?gTasks)
&*&
// Access permissions for every task
// TODO: Convert to read permissions
// ∀t ∈ gTasks. sharedSeg_TCB_p(t)
foreach(gTasks, sharedSeg_TCB_p)
// (RP-All) Read permissions for every task
// ∀t ∈ gTasks. [1/2]sharedSeg_TCB_p(t)
foreach(gTasks, readOnly_sharedSeg_TCB_p)
&*&
// (RP-Current) Read permission for task currently scheduled on this core
// (RP-All) + (RP-Current) => Write permission for scheduled task
[1/2]sharedSeg_TCB_p(gCurrentTCB)
&*&
readyLists_p(?gCellLists, ?gOwnerLists)
&*&