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/*
* FreeRTOS V202104.00
* Copyright (C) 2020 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://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
/* Non-Secure callable functions. */
#include "nsc_functions.h"
/**
* @brief Counter incremented in the callback which is called from the secure
* side.
*
* The size of an MPU region must be a multiple of 32 bytes. Therefore we need
* to declare an array of size 8 to ensure that the total size is 32 bytes -
* even though we only need 4 bytes. If we do not do that, anything placed after
* 4 bytes and upto 32 bytes will also fall in the same MPU region and the task
* having access to ulNonSecureCounter will also have access to all those items.
*/
static uint32_t ulNonSecureCounter[8] __attribute__( ( aligned( 32 ) ) ) = { 0 };
/*-----------------------------------------------------------*/
/**
* @brief Creates all the tasks for TZ demo.
*/
void vStartTZDemo( void );
/**
* @brief Increments the ulNonSecureCounter.
*
* This function is called from the secure side.
*/
static void prvCallback( void );
/**
* @brief Implements the task which calls the functions exported from the secure
* side.
*
* @param pvParameters[in] Parameters as passed during task creation.
*/
static void prvSecureCallingTask( void * pvParameters );
/*-----------------------------------------------------------*/
void vStartTZDemo( void )
{
static StackType_t xSecureCallingTaskStack[ configMINIMAL_STACK_SIZE ] __attribute__( ( aligned( 32 ) ) );
TaskParameters_t xSecureCallingTaskParameters =
{
.pvTaskCode = prvSecureCallingTask,
.pcName = "SecCalling",
.usStackDepth = configMINIMAL_STACK_SIZE,
.pvParameters = NULL,
.uxPriority = tskIDLE_PRIORITY,
.puxStackBuffer = xSecureCallingTaskStack,
.xRegions = {
{ ulNonSecureCounter, 32, tskMPU_REGION_READ_WRITE | tskMPU_REGION_EXECUTE_NEVER },
{ 0, 0, 0 },
{ 0, 0, 0 },
}
};
/* Create an unprivileged task which calls secure functions. */
xTaskCreateRestricted( &( xSecureCallingTaskParameters ), NULL );
}
/*-----------------------------------------------------------*/
static void prvCallback( void )
{
/* This function is called from the secure side. Just increment the counter
* here. The check that this counter keeps incrementing is performed in the
* prvSecureCallingTask. */
ulNonSecureCounter[ 0 ] += 1;
}
/*-----------------------------------------------------------*/
static void prvSecureCallingTask( void * pvParameters )
{
uint32_t ulLastSecureCounter = 0, ulLastNonSecureCounter = 0;
uint32_t ulCurrentSecureCounter = 0;
/* This task calls secure side functions. So allocate a secure context for
* it. */
portALLOCATE_SECURE_CONTEXT( configMINIMAL_SECURE_STACK_SIZE );
for( ; ; )
{
/* Call the secure side function. It does two things:
* - It calls the supplied function (prvCallback) which in turn
* increments the non-secure counter.
* - It increments the secure counter and returns the incremented value.
* Therefore at the end of this function call both the secure and
* non-secure counters must have been incremented.
*/
ulCurrentSecureCounter = NSCFunction( prvCallback );
/* Make sure that both the counters are incremented. */
configASSERT( ulCurrentSecureCounter == ulLastSecureCounter + 1 );
configASSERT( ulNonSecureCounter[ 0 ] == ulLastNonSecureCounter + 1 );
/* Update the last values for both the counters. */
ulLastSecureCounter = ulCurrentSecureCounter;
ulLastNonSecureCounter = ulNonSecureCounter[ 0 ];
/* Wait for a second. */
vTaskDelay( pdMS_TO_TICKS( 1000 ) );
}
}
/*-----------------------------------------------------------*/
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