FreeRTOS-Kernel/verification/verifast/proof/verifast_lock_predicates.h
2022-11-29 09:47:50 -05:00

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3.2 KiB
C

#ifndef VERIFAST_LOCK_PREDICATES_H
#define VERIFAST_LOCK_PREDICATES_H
/* We follow a minimalistic approach during the definition of the
* lock predicates. So far, the only encapsulate the resources and
* invariants required to verify `vTaskSwitchContext`.
* We are going to extend and refine them when we proceed to verify
* other parts of FRTOS.
*/
/* ----------------------------------------------------------------------
* Core local data and access restrictions.
* Some data in FreeRTOS such as the pointer to TCB of the task running
* on core `C` may only be accessed from core `C`. Such core-local data
* protected by deactivating interrupts.
*/
/*@
predicate interruptState_p(uint32_t coreID, uint32_t state);
fixpoint bool interruptsDisabled_f(uint32_t);
predicate coreLocalInterruptInv_p() =
pointer(&pxCurrentTCBs[coreID_f], ?currentTCB) &*&
//pubTCB_p(currentTCB, 0) &*&
integer_(&xYieldPendings[coreID_f], sizeof(BaseType_t), true, _) &*&
coreLocalSeg_TCB_p(currentTCB, ?gCriticalNesting);
@*/
/* ----------------------------------------------------------------------
* Predicates relevant for all locks
*/
/*@
predicate locked_p(list< pair<real, int> > lockHistory);
@*/
/* ----------------------------------------------------------------------
* Task lock and associated global variables from `tasks.c`
*/
/*@
fixpoint int taskLockID_f();
// Represents an acquired task lock.
predicate taskLock_p();
// Represents the invariant associated with the the task lock, i.e.,
// access permissions to the resources protected by the lock.
predicate taskLockInv_p();
@*/
/* ----------------------------------------------------------------------
* ISR lock and associated global variables from `tasks.c`
*/
/*@
fixpoint int isrLockID_f();
// Represents an unacquired ISR lock.
predicate isrLock_p();
// Represents the invariant associated with the the ISR lock, i.e.,
// access permissions to the resources protected by the lock.
predicate isrLockInv_p();
@*/
/* ----------------------------------------------------------------------
* Resources protected by both locks.
* Note that the task lock may never be acquired after the ISR lock.
*/
/*@
fixpoint int taskISRLockID_f();
predicate taskISRLockInv_p() =
integer_((void*) &uxSchedulerSuspended, sizeof(UBaseType_t), false, _) &*&
integer_(&xSchedulerRunning, sizeof(BaseType_t), true, _)
&*&
// top ready priority must be in range
integer_((void*) &uxTopReadyPriority, sizeof(UBaseType_t), false, ?gTopReadyPriority) &*&
0 <= gTopReadyPriority &*& gTopReadyPriority < configMAX_PRIORITIES
&*&
readyLists_p(?gCellLists) &*&
true;
lemma void produce_taskISRLockInv();
requires locked_p(?heldLocks) &*&
heldLocks == cons(?i, cons(?t, nil)) &*&
i == pair(?f_isr, isrLockID_f()) &*&
t == pair(?f_task, taskLockID_f());
ensures locked_p( cons( pair(_, taskISRLockID_f()), heldLocks) ) &*&
taskISRLockInv_p();
lemma void consume_taskISRLockInv();
requires locked_p( cons( pair(_, taskISRLockID_f()), ?otherLocks) ) &*&
taskISRLockInv_p();
ensures locked_p(otherLocks);
@*/
#endif /* VERIFAST_LOCK_PREDICATES_H */