mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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89 lines
3.9 KiB
C
89 lines
3.9 KiB
C
/*
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* FreeRTOS VeriFast Proofs
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* Copyright (C) Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "proof/queue.h"
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#include "proof/queuecontracts.h"
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BaseType_t xQueuePeekFromISR( QueueHandle_t xQueue, void * const pvBuffer )
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/*@requires [1/2]queuehandle(xQueue, ?N, ?M, ?is_isr) &*& is_isr == true &*&
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chars(pvBuffer, M, ?x);@*/
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/*@ensures [1/2]queuehandle(xQueue, N, M, is_isr) &*&
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(result == pdPASS ? chars(pvBuffer, M, _) : chars(pvBuffer, M, x));@*/
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{
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BaseType_t xReturn;
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UBaseType_t uxSavedInterruptStatus;
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int8_t *pcOriginalReadPosition;
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#ifdef VERIFAST /*< const pointer declaration */
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Queue_t * pxQueue = xQueue;
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#else
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Queue_t * const pxQueue = xQueue;
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configASSERT( pxQueue );
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configASSERT( !( ( pvBuffer == NULL ) && ( pxQueue->uxItemSize != ( UBaseType_t ) 0U ) ) );
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configASSERT( pxQueue->uxItemSize != 0 ); /* Can't peek a semaphore. */
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#endif
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/* RTOS ports that support interrupt nesting have the concept of a maximum
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system call (or maximum API call) interrupt priority. Interrupts that are
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above the maximum system call priority are kept permanently enabled, even
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when the RTOS kernel is in a critical section, but cannot make any calls to
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FreeRTOS API functions. If configASSERT() is defined in FreeRTOSConfig.h
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then portASSERT_IF_INTERRUPT_PRIORITY_INVALID() will result in an assertion
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failure if a FreeRTOS API function is called from an interrupt that has been
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assigned a priority above the configured maximum system call priority.
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Only FreeRTOS functions that end in FromISR can be called from interrupts
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that have been assigned a priority at or (logically) below the maximum
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system call interrupt priority. FreeRTOS maintains a separate interrupt
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safe API to ensure interrupt entry is as fast and as simple as possible.
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More information (albeit Cortex-M specific) is provided on the following
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link: http://www.freertos.org/RTOS-Cortex-M3-M4.html */
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portASSERT_IF_INTERRUPT_PRIORITY_INVALID();
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uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();
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/*@assert queue(pxQueue, ?Storage, N, M, ?W, ?R, ?K, ?is_locked, ?abs);@*/
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{
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/* Cannot block in an ISR, so check there is data available. */
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if( pxQueue->uxMessagesWaiting > ( UBaseType_t ) 0 )
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{
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traceQUEUE_PEEK_FROM_ISR( pxQueue );
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/* Remember the read position so it can be reset as nothing is
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actually being removed from the queue. */
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pcOriginalReadPosition = pxQueue->u.xQueue.pcReadFrom;
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/*@close queue(pxQueue, Storage, N, M, W, R, K, is_locked, abs);@*/
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prvCopyDataFromQueue( pxQueue, pvBuffer );
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pxQueue->u.xQueue.pcReadFrom = pcOriginalReadPosition;
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/*@close queue(pxQueue, Storage, N, M, W, R, K, is_locked, abs);@*/
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xReturn = pdPASS;
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}
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else
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{
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xReturn = pdFAIL;
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traceQUEUE_PEEK_FROM_ISR_FAILED( pxQueue );
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}
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}
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/*@close queue(pxQueue, Storage, N, M, W, R, K, is_locked, abs);@*/
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portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );
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return xReturn;
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}
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