mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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155 lines
No EOL
4.7 KiB
C
155 lines
No EOL
4.7 KiB
C
#ifndef VERIFAST_LOCK_PREDICATES_H
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#define VERIFAST_LOCK_PREDICATES_H
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/* We follow a minimalistic approach during the definition of the
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* lock predicates. So far, the only encapsulate the resources and
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* invariants required to verify `vTaskSwitchContext`.
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* We are going to extend and refine them when we proceed to verify
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* other parts of FRTOS.
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*/
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/* ----------------------------------------------------------------------
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* Core local data and access restrictions.
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* Some data in FreeRTOS such as the pointer to TCB of the task running
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* on core `C` may only be accessed from core `C`. Such core-local data
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* protected by deactivating interrupts.
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*/
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/*@
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predicate interruptState_p(uint32_t coreID, uint32_t state);
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fixpoint bool interruptsDisabled_f(uint32_t);
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predicate coreLocalInterruptInv_p() =
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[0.5]pointer(&pxCurrentTCBs[coreID_f], ?currentTCB) &*&
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//pubTCB_p(currentTCB, 0) &*&
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integer_(&xYieldPendings[coreID_f], sizeof(BaseType_t), true, _) &*&
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coreLocalSeg_TCB_p(currentTCB, ?gCriticalNesting);
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@*/
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/* ----------------------------------------------------------------------
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* Predicates relevant for all locks
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*/
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/*@
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predicate locked_p(list< pair<real, int> > lockHistory);
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@*/
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/* ----------------------------------------------------------------------
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* Task lock and associated global variables from `tasks.c`
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*/
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/*@
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fixpoint int taskLockID_f();
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// Represents an acquired task lock.
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predicate taskLock_p();
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// Represents the invariant associated with the the task lock, i.e.,
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// access permissions to the resources protected by the lock.
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predicate taskLockInv_p();
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@*/
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/* ----------------------------------------------------------------------
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* ISR lock and associated global variables from `tasks.c`
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*/
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/*@
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fixpoint int isrLockID_f();
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// Represents an unacquired ISR lock.
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predicate isrLock_p();
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// Represents the invariant associated with the the ISR lock, i.e.,
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// access permissions to the resources protected by the lock.
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predicate isrLockInv_p();
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@*/
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/* ----------------------------------------------------------------------
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* Resources protected by both locks.
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* Note that the task lock may never be acquired after the ISR lock.
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*/
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/*@
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fixpoint int taskISRLockID_f();
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predicate taskISRLockInv_p() =
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// Access to global variables
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[0.5]pointer(&pxCurrentTCBs[coreID_f], ?gCurrentTCB) &*&
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integer_((void*) &uxSchedulerSuspended, sizeof(UBaseType_t), false, _) &*&
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integer_(&xSchedulerRunning, sizeof(BaseType_t), true, _)
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&*&
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// top ready priority must be in range
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integer_((void*) &uxTopReadyPriority, sizeof(UBaseType_t), false, ?gTopReadyPriority) &*&
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0 <= gTopReadyPriority &*& gTopReadyPriority < configMAX_PRIORITIES
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&*&
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// tasks / TCBs
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exists_in_taskISRLockInv_p(?gTasks)
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&*&
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// (RP-All) Read permissions for every task
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// ∀t ∈ gTasks. [1/2]sharedSeg_TCB_p(t)
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foreach(gTasks, readOnly_sharedSeg_TCB_p)
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&*&
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// (RP-Current) Read permission for task currently scheduled on this core
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// (RP-All) + (RP-Current) => Write permission for scheduled task
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[1/2]sharedSeg_TCB_p(gCurrentTCB)
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&*&
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readyLists_p(?gCellLists, ?gOwnerLists)
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&*&
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// gTasks contains all relevant tasks
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mem(gCurrentTCB, gTasks) == true
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&*&
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// ∀l ∈ gOwnerLists. l ⊆ gTasks
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forall(gOwnerLists, (superset)(gTasks)) == true;
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lemma void produce_taskISRLockInv();
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requires locked_p(?heldLocks) &*&
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heldLocks == cons(?i, cons(?t, nil)) &*&
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i == pair(?f_isr, isrLockID_f()) &*&
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t == pair(?f_task, taskLockID_f());
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ensures locked_p( cons( pair(_, taskISRLockID_f()), heldLocks) ) &*&
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taskISRLockInv_p();
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lemma void consume_taskISRLockInv();
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requires locked_p( cons( pair(_, taskISRLockID_f()), ?otherLocks) ) &*&
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taskISRLockInv_p();
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ensures locked_p(otherLocks);
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// Auxiliary predicate to assing names to existentially quantified variables.
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// Having multiple `exists` chunks on the heap makes matching against their
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// arguments ambiguous in most cases.
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predicate exists_in_taskISRLockInv_p(list<void*> gTasks) =
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exists(gTasks);
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// Auxiliary function that allows us to partially apply the list argument.
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//
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// Notes:
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// - Partial application of fixpoint functions in VeriFast is not documented.
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// The syntax for partially application is `(<fixpoint_fct>)(<first_arg>)`
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// - VeriFast only supports partially applying the first argument, e.g.,
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// `(mem)(0)` is allowed but `(mem)(_)(nil)` is not.
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fixpoint bool mem_list_elem<t>(list<t> xs, t x) {
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return mem(x, xs);
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}
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@*/
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#endif /* VERIFAST_LOCK_PREDICATES_H */ |