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feat(freertos-smp): Reintroduce Light Weight Critical Sections

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This commit is contained in:
Sudeep Mohanty 2025-08-22 16:56:30 +02:00
parent fbd37a219e
commit f46aaa7a2b
3 changed files with 134 additions and 0 deletions
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4
include/FreeRTOS.h
View file

@ -2966,6 +2966,10 @@
#error configUSE_PORT_OPTIMISED_TASK_SELECTION is not supported in SMP FreeRTOS
#endif
#ifndef configLIGHTWEIGHT_CRITICAL_SECTION
#define configLIGHTWEIGHT_CRITICAL_SECTION 0
#endif
#ifndef configINITIAL_TICK_COUNT
#define configINITIAL_TICK_COUNT 0
#endif

16
include/task.h
View file

@ -3933,6 +3933,22 @@ void vTaskInternalSetTimeOutState( TimeOut_t * const pxTimeOut ) PRIVILEGED_FUNC
void vTaskExitCriticalFromISR( UBaseType_t uxSavedInterruptStatus );
#endif
/*
* This function is only intended for use when disabling or enabling preemption of a task.
* This function takes only the kernel ISR lock, not the task lock.
*/
#if ( configLIGHTWEIGHT_CRITICAL_SECTION == 1 )
void vKernelLightWeightEnterCritical( void );
#endif
/*
* This function is only intended for use when disabling or enabling preemption of a task.
* This function releases only the kernel ISR lock, not the task lock.
*/
#if ( configLIGHTWEIGHT_CRITICAL_SECTION == 1 )
void vKernelLightWeightExitCritical( void );
#endif
#if ( portUSING_MPU_WRAPPERS == 1 )
/*

114
tasks.c
View file

@ -854,6 +854,14 @@ static void prvAddNewTaskToReadyList( TCB_t * pxNewTCB ) PRIVILEGED_FUNCTION;
TaskHandle_t * const pxCreatedTask ) PRIVILEGED_FUNCTION;
#endif /* #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) */
/* Lightweight critical section helpers (re-introduced) */
#if ( configLIGHTWEIGHT_CRITICAL_SECTION == 1 )
/* Checks to see if another task moved the current task out of the ready
* list while it was waiting to enter a lightweight critical section and yields, if so. */
static void prvLightWeightCheckForRunStateChange( void );
#endif
/*
* Helper function to enable preemption for a task.
*/
@ -7779,6 +7787,112 @@ static void prvResetNextTaskUnblockTime( void )
#endif /* #if ( configNUMBER_OF_CORES > 1 ) */
/*-----------------------------------------------------------*/
#if ( configLIGHTWEIGHT_CRITICAL_SECTION == 1 )
static void prvLightWeightCheckForRunStateChange( void )
{
const TCB_t * pxThisTCB;
BaseType_t xCoreID = ( BaseType_t ) portGET_CORE_ID();
/* Must not be called from ISR context. */
portASSERT_IF_IN_ISR();
/* Called with interrupts disabled. Safe to read pxCurrentTCBs. */
pxThisTCB = pxCurrentTCBs[ xCoreID ];
while( pxThisTCB->xTaskRunState == taskTASK_SCHEDULED_TO_YIELD )
{
UBaseType_t uxPrevCriticalNesting;
/* Save nesting and temporarily release ISR lock if needed to service pending IPI. */
uxPrevCriticalNesting = portGET_CRITICAL_NESTING_COUNT( xCoreID );
if( uxPrevCriticalNesting > 0U )
{
portSET_CRITICAL_NESTING_COUNT( xCoreID, 0U );
kernelRELEASE_ISR_LOCK( xCoreID );
}
portMEMORY_BARRIER();
/* Allow the core to service pending yield interrupt. */
portENABLE_INTERRUPTS();
portDISABLE_INTERRUPTS();
/* Reacquire ISR lock and restore nesting; re-evaluate run state. */
xCoreID = ( BaseType_t ) portGET_CORE_ID();
kernelGET_ISR_LOCK( xCoreID );
portSET_CRITICAL_NESTING_COUNT( xCoreID, uxPrevCriticalNesting );
pxThisTCB = pxCurrentTCBs[ xCoreID ];
}
}
void vKernelLightWeightEnterCritical( void )
{
if( xSchedulerRunning != pdFALSE )
{
portDISABLE_INTERRUPTS();
{
const BaseType_t xCoreID = ( BaseType_t ) portGET_CORE_ID();
/* Take only the ISR lock, not the task lock. */
kernelGET_ISR_LOCK( xCoreID );
portINCREMENT_CRITICAL_NESTING_COUNT( xCoreID );
if( portGET_CRITICAL_NESTING_COUNT( xCoreID ) == 1U )
{
prvLightWeightCheckForRunStateChange();
}
}
}
}
void vKernelLightWeightExitCritical( void )
{
if( xSchedulerRunning != pdFALSE )
{
const BaseType_t xCoreID = ( BaseType_t ) portGET_CORE_ID();
if( portGET_CRITICAL_NESTING_COUNT( xCoreID ) > 0U )
{
BaseType_t xYieldCurrentTask;
if( ( xYieldPendings[ xCoreID ] == pdTRUE ) && ( uxSchedulerSuspended == pdFALSE )
#if ( configUSE_TASK_PREEMPTION_DISABLE == 1 )
&& ( pxCurrentTCBs[ xCoreID ]->uxPreemptionDisable == 0U ) &&
( pxCurrentTCBs[ xCoreID ]->uxDeferredStateChange == 0U )
#endif
)
{
xYieldCurrentTask = pdTRUE;
}
else
{
xYieldCurrentTask = pdFALSE;
}
/* Release only the ISR lock. */
kernelRELEASE_ISR_LOCK( xCoreID );
portDECREMENT_CRITICAL_NESTING_COUNT( xCoreID );
if( portGET_CRITICAL_NESTING_COUNT( xCoreID ) == 0U )
{
portENABLE_INTERRUPTS();
if( xYieldCurrentTask != pdFALSE )
{
portYIELD();
}
}
}
}
}
#endif /* configLIGHTWEIGHT_CRITICAL_SECTION == 1 */
/*-----------------------------------------------------------*/
#if ( configUSE_STATS_FORMATTING_FUNCTIONS > 0 )
static char * prvWriteNameToBuffer( char * pcBuffer,