/*
* SPDX-FileCopyrightText: 2020 Amazon.com, Inc. or its affiliates
*
* SPDX-License-Identifier: MIT
*/
/*
* FreeRTOS Kernel V10.4.3
* 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.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the Posix port.
*
* Each task has a pthread which eases use of standard debuggers
* (allowing backtraces of tasks etc). Threads for tasks that are not
* running are blocked in sigwait().
*
* Task switch is done by resuming the thread for the next task by
* signaling the condition variable and then waiting on a condition variable
* with the current thread.
*
* The timer interrupt uses SIGALRM and care is taken to ensure that
* the signal handler runs only on the thread for the current task.
*
* Use of part of the standard C library requires care as some
* functions can take pthread mutexes internally which can result in
* deadlocks as the FreeRTOS kernel can switch tasks while they're
* holding a pthread mutex.
*
* stdio (printf() and friends) should be called from a single task
* only or serialized with a FreeRTOS primitive such as a binary
* semaphore or mutex.
*----------------------------------------------------------*/
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <sys/times.h>
#include <time.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "timers.h"
#include "utils/wait_for_event.h"
/*-----------------------------------------------------------*/
#define SIG_RESUME SIGUSR1
typedef struct THREAD
{
pthread_t pthread;
TaskFunction_t pxCode;
void *pvParams;
BaseType_t xDying;
struct event *ev;
} Thread_t;
/*
* The additional per-thread data is stored at the beginning of the
* task's stack.
*/
static inline Thread_t *prvGetThreadFromTask(TaskHandle_t xTask)
{
StackType_t *pxTopOfStack = *(StackType_t **)xTask;
return (Thread_t *)(pxTopOfStack + 1);
}
/*-----------------------------------------------------------*/
static pthread_once_t hSigSetupThread = PTHREAD_ONCE_INIT;
static sigset_t xAllSignals;
static sigset_t xSchedulerOriginalSignalMask;
static pthread_t hMainThread = ( pthread_t )NULL;
static volatile portBASE_TYPE uxCriticalNesting;
/*-----------------------------------------------------------*/
static portBASE_TYPE xSchedulerEnd = pdFALSE;
/*-----------------------------------------------------------*/
static void prvSetupSignalsAndSchedulerPolicy( void );
static void prvSetupTimerInterrupt( void );
static void *prvWaitForStart( void * pvParams );
static void prvSwitchThread( Thread_t * xThreadToResume,
Thread_t *xThreadToSuspend );
static void prvSuspendSelf( Thread_t * thread);
static void prvResumeThread( Thread_t * xThreadId );
static void vPortSystemTickHandler( int sig );
static void vPortStartFirstTask( void );
/*-----------------------------------------------------------*/
static void prvFatalError( const char *pcCall, int iErrno )
{
fprintf( stderr, "%s: %s\n", pcCall, strerror( iErrno ) );
abort();
}
/*
* See header file for description.
*/
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack,
portSTACK_TYPE *pxEndOfStack,
TaskFunction_t pxCode, void *pvParameters )
{
Thread_t *thread;
pthread_attr_t xThreadAttributes;
size_t ulStackSize;
int iRet;
(void)pthread_once( &hSigSetupThread, prvSetupSignalsAndSchedulerPolicy );
/*
* Store the additional thread data at the start of the stack.
*/
thread = (Thread_t *)(pxTopOfStack + 1) - 1;
pxTopOfStack = (portSTACK_TYPE *)thread - 1;
ulStackSize = (pxTopOfStack + 1 - pxEndOfStack) * sizeof(*pxTopOfStack);
thread->pxCode = pxCode;
thread->pvParams = pvParameters;
thread->xDying = pdFALSE;
pthread_attr_init( &xThreadAttributes );
pthread_attr_setstack( &xThreadAttributes, pxEndOfStack, ulStackSize );
thread->ev = event_create();
vPortEnterCritical();
iRet = pthread_create( &thread->pthread, &xThreadAttributes,
prvWaitForStart, thread );
if ( iRet )
{
prvFatalError( "pthread_create", iRet );
}
vPortExitCritical();
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
void vPortStartFirstTask( void )
{
Thread_t *pxFirstThread = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
/* Start the first task. */
prvResumeThread( pxFirstThread );
}
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
portBASE_TYPE xPortStartScheduler( void )
{
int iSignal;
sigset_t xSignals;
hMainThread = pthread_self();
/* Start the timer that generates the tick ISR(SIGALRM).
Interrupts are disabled here already. */
prvSetupTimerInterrupt();
/* Start the first task. */
vPortStartFirstTask();
/* Wait until signaled by vPortEndScheduler(). */
sigemptyset( &xSignals );
sigaddset( &xSignals, SIG_RESUME );
while ( !xSchedulerEnd )
{
sigwait( &xSignals, &iSignal );
}
/* Cancel the Idle task and free its resources */
#if ( INCLUDE_xTaskGetIdleTaskHandle == 1 )
vPortCancelThread( xTaskGetIdleTaskHandle() );
#endif
#if ( configUSE_TIMERS == 1 )
/* Cancel the Timer task and free its resources */
vPortCancelThread( xTimerGetTimerDaemonTaskHandle() );
#endif /* configUSE_TIMERS */
/* Restore original signal mask. */
(void)pthread_sigmask( SIG_SETMASK, &xSchedulerOriginalSignalMask, NULL );
return 0;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
struct itimerval itimer;
struct sigaction sigtick;
Thread_t *xCurrentThread;
/* Stop the timer and ignore any pending SIGALRMs that would end
* up running on the main thread when it is resumed. */
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = 0;
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = 0;
(void)setitimer( ITIMER_REAL, &itimer, NULL );
sigtick.sa_flags = 0;
sigtick.sa_handler = SIG_IGN;
sigemptyset( &sigtick.sa_mask );
sigaction( SIGALRM, &sigtick, NULL );
/* Signal the scheduler to exit its loop. */
xSchedulerEnd = pdTRUE;
(void)pthread_kill( hMainThread, SIG_RESUME );
xCurrentThread = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
prvSuspendSelf(xCurrentThread);
}
/*-----------------------------------------------------------*/
void vPortEnterCritical( void )
{
if ( uxCriticalNesting == 0 )
{
vPortDisableInterrupts();
}
uxCriticalNesting++;
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
uxCriticalNesting--;
/* If we have reached 0 then re-enable the interrupts. */
if( uxCriticalNesting == 0 )
{
vPortEnableInterrupts();
}
}
/*-----------------------------------------------------------*/
void vPortYieldFromISR( void )
{
Thread_t *xThreadToSuspend;
Thread_t *xThreadToResume;
xThreadToSuspend = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
vTaskSwitchContext();
xThreadToResume = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
prvSwitchThread( xThreadToResume, xThreadToSuspend );
}
/*-----------------------------------------------------------*/
void vPortYield( void )
{
vPortEnterCritical();
vPortYieldFromISR();
vPortExitCritical();
}
/*-----------------------------------------------------------*/
void vPortDisableInterrupts( void )
{
pthread_sigmask( SIG_BLOCK, &xAllSignals, NULL );
}
/*-----------------------------------------------------------*/
void vPortEnableInterrupts( void )
{
pthread_sigmask( SIG_UNBLOCK, &xAllSignals, NULL );
}
/*-----------------------------------------------------------*/
portBASE_TYPE xPortSetInterruptMask( void )
{
/* Interrupts are always disabled inside ISRs (signals
handlers). */
return pdTRUE;
}
/*-----------------------------------------------------------*/
void vPortClearInterruptMask( portBASE_TYPE xMask )
{
}
/*-----------------------------------------------------------*/
static uint64_t prvGetTimeNs(void)
{
struct timespec t;
clock_gettime(CLOCK_MONOTONIC, &t);
return t.tv_sec * 1000000000ull + t.tv_nsec;
}
static uint64_t prvStartTimeNs;
/* commented as part of the code below in vPortSystemTickHandler,
* to adjust timing according to full demo requirements */
/* static uint64_t prvTickCount; */
/*
* Setup the systick timer to generate the tick interrupts at the required
* frequency.
*/
void prvSetupTimerInterrupt( void )
{
struct itimerval itimer;
int iRet;
/* Initialise the structure with the current timer information. */
iRet = getitimer( ITIMER_REAL, &itimer );
if ( iRet )
{
prvFatalError( "getitimer", errno );
}
/* Set the interval between timer events. */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = portTICK_RATE_MICROSECONDS;
/* Set the current count-down. */
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = portTICK_RATE_MICROSECONDS;
/* Set-up the timer interrupt. */
iRet = setitimer( ITIMER_REAL, &itimer, NULL );
if ( iRet )
{
prvFatalError( "setitimer", errno );
}
prvStartTimeNs = prvGetTimeNs();
}
/*-----------------------------------------------------------*/
static void vPortSystemTickHandler( int sig )
{
Thread_t *pxThreadToSuspend;
Thread_t *pxThreadToResume;
/* uint64_t xExpectedTicks; */
uxCriticalNesting++; /* Signals are blocked in this signal handler. */
#if ( configUSE_PREEMPTION == 1 )
pxThreadToSuspend = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
#endif
/* Tick Increment, accounting for any lost signals or drift in
* the timer. */
/*
* Comment code to adjust timing according to full demo requirements
* xExpectedTicks = (prvGetTimeNs() - prvStartTimeNs)
* / (portTICK_RATE_MICROSECONDS * 1000);
* do { */
xTaskIncrementTick();
/* prvTickCount++;
* } while (prvTickCount < xExpectedTicks);
*/
#if ( configUSE_PREEMPTION == 1 )
/* Select Next Task. */
vTaskSwitchContext();
pxThreadToResume = prvGetThreadFromTask( xTaskGetCurrentTaskHandle() );
prvSwitchThread(pxThreadToResume, pxThreadToSuspend);
#endif
uxCriticalNesting--;
}
/*-----------------------------------------------------------*/
void vPortThreadDying( void *pxTaskToDelete, volatile BaseType_t *pxPendYield )
{
Thread_t *pxThread = prvGetThreadFromTask( pxTaskToDelete );
pxThread->xDying = pdTRUE;
}
void vPortCancelThread( void *pxTaskToDelete )
{
Thread_t *pxThreadToCancel = prvGetThreadFromTask( pxTaskToDelete );
/*
* The thread has already been suspended so it can be safely cancelled.
*/
pthread_cancel( pxThreadToCancel->pthread );
pthread_join( pxThreadToCancel->pthread, NULL );
event_delete( pxThreadToCancel->ev );
}
/*-----------------------------------------------------------*/
static void *prvWaitForStart( void * pvParams )
{
Thread_t *pxThread = pvParams;
prvSuspendSelf(pxThread);
/* Resumed for the first time, unblocks all signals. */
uxCriticalNesting = 0;
vPortEnableInterrupts();
/* Call the task's entry point. */
pxThread->pxCode( pxThread->pvParams );
/* A function that implements a task must not exit or attempt to return to
* its caller as there is nothing to return to. If a task wants to exit it
* should instead call vTaskDelete( NULL ). Artificially force an assert()
* to be triggered if configASSERT() is defined, so application writers can
* catch the error. */
configASSERT( pdFALSE );
return NULL;
}
/*-----------------------------------------------------------*/
static void prvSwitchThread( Thread_t *pxThreadToResume,
Thread_t *pxThreadToSuspend )
{
BaseType_t uxSavedCriticalNesting;
if ( pxThreadToSuspend != pxThreadToResume )
{
/*
* Switch tasks.
*
* The critical section nesting is per-task, so save it on the
* stack of the current (suspending thread), restoring it when
* we switch back to this task.
*/
uxSavedCriticalNesting = uxCriticalNesting;
prvResumeThread( pxThreadToResume );
if ( pxThreadToSuspend->xDying )
{
pthread_exit( NULL );
}
prvSuspendSelf( pxThreadToSuspend );
uxCriticalNesting = uxSavedCriticalNesting;
}
}
/*-----------------------------------------------------------*/
static void prvSuspendSelf( Thread_t *thread )
{
/*
* Suspend this thread by waiting for a pthread_cond_signal event.
*
* A suspended thread must not handle signals (interrupts) so
* all signals must be blocked by calling this from:
*
* - Inside a critical section (vPortEnterCritical() /
* vPortExitCritical()).
*
* - From a signal handler that has all signals masked.
*
* - A thread with all signals blocked with pthread_sigmask().
*/
event_wait(thread->ev);
}
/*-----------------------------------------------------------*/
static void prvResumeThread( Thread_t *xThreadId )
{
if ( pthread_self() != xThreadId->pthread )
{
event_signal(xThreadId->ev);
}
}
/*-----------------------------------------------------------*/
static void prvSetupSignalsAndSchedulerPolicy( void )
{
struct sigaction sigresume, sigtick;
int iRet;
hMainThread = pthread_self();
/* Initialise common signal masks. */
sigfillset( &xAllSignals );
/* Don't block SIGINT so this can be used to break into GDB while
* in a critical section. */
sigdelset( &xAllSignals, SIGINT );
/*
* Block all signals in this thread so all new threads
* inherits this mask.
*
* When a thread is resumed for the first time, all signals
* will be unblocked.
*/
(void)pthread_sigmask( SIG_SETMASK, &xAllSignals,
&xSchedulerOriginalSignalMask );
/* SIG_RESUME is only used with sigwait() so doesn't need a
handler. */
sigresume.sa_flags = 0;
sigresume.sa_handler = SIG_IGN;
sigfillset( &sigresume.sa_mask );
sigtick.sa_flags = 0;
sigtick.sa_handler = vPortSystemTickHandler;
sigfillset( &sigtick.sa_mask );
iRet = sigaction( SIG_RESUME, &sigresume, NULL );
if ( iRet )
{
prvFatalError( "sigaction", errno );
}
iRet = sigaction( SIGALRM, &sigtick, NULL );
if ( iRet )
{
prvFatalError( "sigaction", errno );
}
}
/*-----------------------------------------------------------*/
unsigned long ulPortGetRunTime( void )
{
struct tms xTimes;
times( &xTimes );
return ( unsigned long ) xTimes.tms_utime;
}
/*-----------------------------------------------------------*/