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tasks.c
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tasks.c
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/*
* FreeRTOS SMP Kernel V202110.00
* 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.
*
* https://www.FreeRTOS.org
* https://github.com/FreeRTOS
*
*/
/* Standard includes. */
#include <stdlib.h>
#include <string.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
* all the API functions to use the MPU wrappers. That should only be done when
* task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "timers.h"
#include "stack_macros.h"
/* Lint e9021, e961 and e750 are suppressed as a MISRA exception justified
* because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
* for the header files above, but not in this file, in order to generate the
* correct privileged Vs unprivileged linkage and placement. */
#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750 !e9021. */
/* Set configUSE_STATS_FORMATTING_FUNCTIONS to 2 to include the stats formatting
* functions but without including stdio.h here. */
#if ( configUSE_STATS_FORMATTING_FUNCTIONS == 1 )
/* At the bottom of this file are two optional functions that can be used
* to generate human readable text from the raw data generated by the
* uxTaskGetSystemState() function. Note the formatting functions are provided
* for convenience only, and are NOT considered part of the kernel. */
#include <stdio.h>
#endif /* configUSE_STATS_FORMATTING_FUNCTIONS == 1 ) */
#if ( configUSE_PREEMPTION == 0 )
/* If the cooperative scheduler is being used then a yield should not be
* performed just because a higher priority task has been woken. */
#define taskYIELD_IF_USING_PREEMPTION()
#else
#define taskYIELD_IF_USING_PREEMPTION() vTaskYieldWithinAPI()
#endif
/* Values that can be assigned to the ucNotifyState member of the TCB. */
#define taskNOT_WAITING_NOTIFICATION ( ( uint8_t ) 0 ) /* Must be zero as it is the initialised value. */
#define taskWAITING_NOTIFICATION ( ( uint8_t ) 1 )
#define taskNOTIFICATION_RECEIVED ( ( uint8_t ) 2 )
/*
* The value used to fill the stack of a task when the task is created. This
* is used purely for checking the high water mark for tasks.
*/
#define tskSTACK_FILL_BYTE ( 0xa5U )
/* Bits used to record how a task's stack and TCB were allocated. */
#define tskDYNAMICALLY_ALLOCATED_STACK_AND_TCB ( ( uint8_t ) 0 )
#define tskSTATICALLY_ALLOCATED_STACK_ONLY ( ( uint8_t ) 1 )
#define tskSTATICALLY_ALLOCATED_STACK_AND_TCB ( ( uint8_t ) 2 )
/* If any of the following are set then task stacks are filled with a known
* value so the high water mark can be determined. If none of the following are
* set then don't fill the stack so there is no unnecessary dependency on memset. */
#if ( ( configCHECK_FOR_STACK_OVERFLOW > 1 ) || ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark2 == 1 ) )
#define tskSET_NEW_STACKS_TO_KNOWN_VALUE 1
#else
#define tskSET_NEW_STACKS_TO_KNOWN_VALUE 0
#endif
/*
* Macros used by vListTask to indicate which state a task is in.
*/
#define tskRUNNING_CHAR ( 'X' )
#define tskBLOCKED_CHAR ( 'B' )
#define tskREADY_CHAR ( 'R' )
#define tskDELETED_CHAR ( 'D' )
#define tskSUSPENDED_CHAR ( 'S' )
/*
* Some kernel aware debuggers require the data the debugger needs access to to
* be global, rather than file scope.
*/
#ifdef portREMOVE_STATIC_QUALIFIER
#define static
#endif
/* The name allocated to the Idle task. This can be overridden by defining
* configIDLE_TASK_NAME in FreeRTOSConfig.h. */
#ifndef configIDLE_TASK_NAME
#define configIDLE_TASK_NAME "IDLE"
#endif
#if ( configUSE_PORT_OPTIMISED_TASK_SELECTION == 0 )
/* If configUSE_PORT_OPTIMISED_TASK_SELECTION is 0 then task selection is
* performed in a generic way that is not optimised to any particular
* microcontroller architecture. */
/* uxTopReadyPriority holds the priority of the highest priority ready
* state task. */
#define taskRECORD_READY_PRIORITY( uxPriority ) \
{ \
if( ( uxPriority ) > uxTopReadyPriority ) \
{ \
uxTopReadyPriority = ( uxPriority ); \
} \
} /* taskRECORD_READY_PRIORITY */
/*-----------------------------------------------------------*/
/* Define away taskRESET_READY_PRIORITY() and portRESET_READY_PRIORITY() as
* they are only required when a port optimised method of task selection is
* being used. */
#define taskRESET_READY_PRIORITY( uxPriority )
#define portRESET_READY_PRIORITY( uxPriority, uxTopReadyPriority )
#else /* configUSE_PORT_OPTIMISED_TASK_SELECTION */
#error configUSE_PORT_OPTIMISED_TASK_SELECTION not yet supported in SMP
/* If configUSE_PORT_OPTIMISED_TASK_SELECTION is 1 then task selection is
* performed in a way that is tailored to the particular microcontroller
* architecture being used. */
/* A port optimised version is provided. Call the port defined macros. */
#define taskRECORD_READY_PRIORITY( uxPriority ) portRECORD_READY_PRIORITY( uxPriority, uxTopReadyPriority )
/*-----------------------------------------------------------*/
/* A port optimised version is provided, call it only if the TCB being reset
* is being referenced from a ready list. If it is referenced from a delayed
* or suspended list then it won't be in a ready list. */
#define taskRESET_READY_PRIORITY( uxPriority ) \
{ \
if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ ( uxPriority ) ] ) ) == ( UBaseType_t ) 0 ) \
{ \
portRESET_READY_PRIORITY( ( uxPriority ), ( uxTopReadyPriority ) ); \
} \
}
#endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */
/*-----------------------------------------------------------*/
/* pxDelayedTaskList and pxOverflowDelayedTaskList are switched when the tick
* count overflows. */
#define taskSWITCH_DELAYED_LISTS() \
{ \
List_t * pxTemp; \
\
/* The delayed tasks list should be empty when the lists are switched. */ \
configASSERT( ( listLIST_IS_EMPTY( pxDelayedTaskList ) ) ); \
\
pxTemp = pxDelayedTaskList; \
pxDelayedTaskList = pxOverflowDelayedTaskList; \
pxOverflowDelayedTaskList = pxTemp; \
xNumOfOverflows++; \
prvResetNextTaskUnblockTime(); \
}
/*-----------------------------------------------------------*/
/*
* Place the task represented by pxTCB into the appropriate ready list for
* the task. It is inserted at the end of the list.
*/
#define prvAddTaskToReadyList( pxTCB ) \
traceMOVED_TASK_TO_READY_STATE( pxTCB ); \
taskRECORD_READY_PRIORITY( ( pxTCB )->uxPriority ); \
vListInsertEnd( &( pxReadyTasksLists[ ( pxTCB )->uxPriority ] ), &( ( pxTCB )->xStateListItem ) ); \
tracePOST_MOVED_TASK_TO_READY_STATE( pxTCB )
/*-----------------------------------------------------------*/
/*
* Several functions take a TaskHandle_t parameter that can optionally be NULL,
* where NULL is used to indicate that the handle of the currently executing
* task should be used in place of the parameter. This macro simply checks to
* see if the parameter is NULL and returns a pointer to the appropriate TCB.
*/
#define prvGetTCBFromHandle( pxHandle ) ( ( ( pxHandle ) == NULL ) ? pxCurrentTCB : ( pxHandle ) )
/* The item value of the event list item is normally used to hold the priority
* of the task to which it belongs (coded to allow it to be held in reverse
* priority order). However, it is occasionally borrowed for other purposes. It
* is important its value is not updated due to a task priority change while it is
* being used for another purpose. The following bit definition is used to inform
* the scheduler that the value should not be changed - in which case it is the
* responsibility of whichever module is using the value to ensure it gets set back
* to its original value when it is released. */
#if ( configUSE_16_BIT_TICKS == 1 )
#define taskEVENT_LIST_ITEM_VALUE_IN_USE 0x8000U
#else
#define taskEVENT_LIST_ITEM_VALUE_IN_USE 0x80000000UL
#endif
/* Indicates that the task is not actively running on any core. */
#define taskTASK_NOT_RUNNING ( TaskRunning_t ) ( -1 )
/* Indicates that the task is actively running but scheduled to yield. */
#define taskTASK_YIELDING ( TaskRunning_t ) ( -2 )
/* Returns pdTRUE if the task is actively running and not scheduled to yield. */
#define taskTASK_IS_RUNNING( xTaskRunState ) ( ( 0 <= xTaskRunState ) && ( xTaskRunState < configNUM_CORES ) )
typedef BaseType_t TaskRunning_t;
/*
* Task control block. A task control block (TCB) is allocated for each task,
* and stores task state information, including a pointer to the task's context
* (the task's run time environment, including register values)
*/
typedef struct tskTaskControlBlock /* The old naming convention is used to prevent breaking kernel aware debuggers. */
{
volatile StackType_t * pxTopOfStack; /*< Points to the location of the last item placed on the tasks stack. THIS MUST BE THE FIRST MEMBER OF THE TCB STRUCT. */
#if ( portUSING_MPU_WRAPPERS == 1 )
xMPU_SETTINGS xMPUSettings; /*< The MPU settings are defined as part of the port layer. THIS MUST BE THE SECOND MEMBER OF THE TCB STRUCT. */
#endif
#if ( configUSE_CORE_AFFINITY == 1 && configNUM_CORES > 1 )
UBaseType_t uxCoreAffinityMask; /*< Used to link the task to certain cores. UBaseType_t must have >= the same number of bits as SMP confNUM_CORES */
#endif
ListItem_t xStateListItem; /*< The list that the state list item of a task is reference from denotes the state of that task (Ready, Blocked, Suspended ). */
ListItem_t xEventListItem; /*< Used to reference a task from an event list. */
UBaseType_t uxPriority; /*< The priority of the task. 0 is the lowest priority. */
StackType_t * pxStack; /*< Points to the start of the stack. */
volatile TaskRunning_t xTaskRunState; /*< Used to identify the core the task is running on, if any. */
BaseType_t xIsIdle; /*< Used to identify the idle tasks. */
char pcTaskName[ configMAX_TASK_NAME_LEN ]; /*< Descriptive name given to the task when created. Facilitates debugging only. */ /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
#if ( configUSE_TASK_PREEMPTION_DISABLE == 1 )
BaseType_t xPreemptionDisable; /*< Used to prevent the task from being preempted */
#endif
#if ( ( portSTACK_GROWTH > 0 ) || ( configRECORD_STACK_HIGH_ADDRESS == 1 ) )
StackType_t * pxEndOfStack; /*< Points to the highest valid address for the stack. */
#endif
#if ( portCRITICAL_NESTING_IN_TCB == 1 )
UBaseType_t uxCriticalNesting; /*< Holds the critical section nesting depth for ports that do not maintain their own count in the port layer. */
#endif
#if ( configUSE_TRACE_FACILITY == 1 )
UBaseType_t uxTCBNumber; /*< Stores a number that increments each time a TCB is created. It allows debuggers to determine when a task has been deleted and then recreated. */
UBaseType_t uxTaskNumber; /*< Stores a number specifically for use by third party trace code. */
#endif
#if ( configUSE_MUTEXES == 1 )
UBaseType_t uxBasePriority; /*< The priority last assigned to the task - used by the priority inheritance mechanism. */
UBaseType_t uxMutexesHeld;
#endif
#if ( configUSE_APPLICATION_TASK_TAG == 1 )
TaskHookFunction_t pxTaskTag;
#endif
#if ( configNUM_THREAD_LOCAL_STORAGE_POINTERS > 0 )
void * pvThreadLocalStoragePointers[ configNUM_THREAD_LOCAL_STORAGE_POINTERS ];
#endif
#if ( configGENERATE_RUN_TIME_STATS == 1 )
uint32_t ulRunTimeCounter; /*< Stores the amount of time the task has spent in the Running state. */
#endif
#if ( configUSE_NEWLIB_REENTRANT == 1 )
/* Allocate a Newlib reent structure that is specific to this task.
* Note Newlib support has been included by popular demand, but is not
* used by the FreeRTOS maintainers themselves. FreeRTOS is not
* responsible for resulting newlib operation. User must be familiar with
* newlib and must provide system-wide implementations of the necessary
* stubs. Be warned that (at the time of writing) the current newlib design
* implements a system-wide malloc() that must be provided with locks.
*
* See the third party link http://www.nadler.com/embedded/newlibAndFreeRTOS.html
* for additional information. */
struct _reent xNewLib_reent;
#endif
#if ( configUSE_TASK_NOTIFICATIONS == 1 )
volatile uint32_t ulNotifiedValue[ configTASK_NOTIFICATION_ARRAY_ENTRIES ];
volatile uint8_t ucNotifyState[ configTASK_NOTIFICATION_ARRAY_ENTRIES ];
#endif
/* See the comments in FreeRTOS.h with the definition of
* tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE. */
#if ( tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE != 0 ) /*lint !e731 !e9029 Macro has been consolidated for readability reasons. */
uint8_t ucStaticallyAllocated; /*< Set to pdTRUE if the task is a statically allocated to ensure no attempt is made to free the memory. */
#endif
#if ( INCLUDE_xTaskAbortDelay == 1 )
uint8_t ucDelayAborted;
#endif
#if ( configUSE_POSIX_ERRNO == 1 )
int iTaskErrno;
#endif
} tskTCB;
/* The old tskTCB name is maintained above then typedefed to the new TCB_t name
* below to enable the use of older kernel aware debuggers. */
typedef tskTCB TCB_t;
/*lint -save -e956 A manual analysis and inspection has been used to determine
* which static variables must be declared volatile. */
PRIVILEGED_DATA TCB_t * volatile pxCurrentTCBs[ configNUM_CORES ] = { NULL };
#define pxCurrentTCB xTaskGetCurrentTaskHandle()
/* Lists for ready and blocked tasks. --------------------
* xDelayedTaskList1 and xDelayedTaskList2 could be moved to function scope but
* doing so breaks some kernel aware debuggers and debuggers that rely on removing
* the static qualifier. */
PRIVILEGED_DATA static List_t pxReadyTasksLists[ configMAX_PRIORITIES ]; /*< Prioritised ready tasks. */
PRIVILEGED_DATA static List_t xDelayedTaskList1; /*< Delayed tasks. */
PRIVILEGED_DATA static List_t xDelayedTaskList2; /*< Delayed tasks (two lists are used - one for delays that have overflowed the current tick count. */
PRIVILEGED_DATA static List_t * volatile pxDelayedTaskList; /*< Points to the delayed task list currently being used. */
PRIVILEGED_DATA static List_t * volatile pxOverflowDelayedTaskList; /*< Points to the delayed task list currently being used to hold tasks that have overflowed the current tick count. */
PRIVILEGED_DATA static List_t xPendingReadyList; /*< Tasks that have been readied while the scheduler was suspended. They will be moved to the ready list when the scheduler is resumed. */
#if ( INCLUDE_vTaskDelete == 1 )
PRIVILEGED_DATA static List_t xTasksWaitingTermination; /*< Tasks that have been deleted - but their memory not yet freed. */
PRIVILEGED_DATA static volatile UBaseType_t uxDeletedTasksWaitingCleanUp = ( UBaseType_t ) 0U;
#endif
#if ( INCLUDE_vTaskSuspend == 1 )
PRIVILEGED_DATA static List_t xSuspendedTaskList; /*< Tasks that are currently suspended. */
#endif
/* Global POSIX errno. Its value is changed upon context switching to match
* the errno of the currently running task. */
#if ( configUSE_POSIX_ERRNO == 1 )
int FreeRTOS_errno = 0;
#endif
/* Other file private variables. --------------------------------*/
PRIVILEGED_DATA static volatile UBaseType_t uxCurrentNumberOfTasks = ( UBaseType_t ) 0U;
PRIVILEGED_DATA static volatile TickType_t xTickCount = ( TickType_t ) configINITIAL_TICK_COUNT;
PRIVILEGED_DATA static volatile UBaseType_t uxTopReadyPriority = tskIDLE_PRIORITY;
PRIVILEGED_DATA static volatile BaseType_t xSchedulerRunning = pdFALSE;
PRIVILEGED_DATA static volatile TickType_t xPendedTicks = ( TickType_t ) 0U;
PRIVILEGED_DATA static volatile BaseType_t xYieldPendings[ configNUM_CORES ] = { pdFALSE };
PRIVILEGED_DATA static volatile BaseType_t xNumOfOverflows = ( BaseType_t ) 0;
PRIVILEGED_DATA static UBaseType_t uxTaskNumber = ( UBaseType_t ) 0U;
PRIVILEGED_DATA static volatile TickType_t xNextTaskUnblockTime = ( TickType_t ) 0U; /* Initialised to portMAX_DELAY before the scheduler starts. */
PRIVILEGED_DATA static TaskHandle_t xIdleTaskHandle[ configNUM_CORES ] = { NULL }; /*< Holds the handle of the idle task. The idle task is created automatically when the scheduler is started. */
#define xYieldPending prvGetCurrentYieldPending()
/* Improve support for OpenOCD. The kernel tracks Ready tasks via priority lists.
* For tracking the state of remote threads, OpenOCD uses uxTopUsedPriority
* to determine the number of priority lists to read back from the remote target. */
const volatile UBaseType_t uxTopUsedPriority = configMAX_PRIORITIES - 1U;
/* Context switches are held pending while the scheduler is suspended. Also,
* interrupts must not manipulate the xStateListItem of a TCB, or any of the
* lists the xStateListItem can be referenced from, if the scheduler is suspended.
* If an interrupt needs to unblock a task while the scheduler is suspended then it
* moves the task's event list item into the xPendingReadyList, ready for the
* kernel to move the task from the pending ready list into the real ready list
* when the scheduler is unsuspended. The pending ready list itself can only be
* accessed from a critical section.
*
* Updates to uxSchedulerSuspended must be protected by both the task and ISR locks and
* must not be done by an ISR. Reads must be protected by either lock and may be done by
* either an ISR or a task. */
PRIVILEGED_DATA static volatile UBaseType_t uxSchedulerSuspended = ( UBaseType_t ) pdFALSE;
#if ( configGENERATE_RUN_TIME_STATS == 1 )
/* Do not move these variables to function scope as doing so prevents the
* code working with debuggers that need to remove the static qualifier. */
PRIVILEGED_DATA static uint32_t ulTaskSwitchedInTime = 0UL; /*< Holds the value of a timer/counter the last time a task was switched in. */
PRIVILEGED_DATA static volatile uint32_t ulTotalRunTime = 0UL; /*< Holds the total amount of execution time as defined by the run time counter clock. */
#endif
/*lint -restore */
/*-----------------------------------------------------------*/
/* File private functions. --------------------------------*/
/*
* Creates the idle tasks during scheduler start
*/
static BaseType_t prvCreateIdleTasks( void );
/*
* Returns the yield pending count for the calling core.
*/
static BaseType_t prvGetCurrentYieldPending( void );
/*
* Checks to see if another task moved the current task out of the ready
* list while it was waiting to enter a critical section and yields if so.
*/
static void prvCheckForRunStateChange( void );
/*
* Yields the given core.
*/
static void prvYieldCore( BaseType_t xCoreID );
/*
* Yields a core, or cores if multiple priorities are not allowed to run
* simultaneously, to allow the task pxTCB to run.
*/
static void prvYieldForTask( TCB_t * pxTCB,
const BaseType_t xPreemptEqualPriority );
/*
* Selects the highest priority available task
*/
static BaseType_t prvSelectHighestPriorityTask( const BaseType_t xCoreID );
/**
* Utility task that simply returns pdTRUE if the task referenced by xTask is
* currently in the Suspended state, or pdFALSE if the task referenced by xTask
* is in any other state.
*/
#if ( INCLUDE_vTaskSuspend == 1 )
static BaseType_t prvTaskIsTaskSuspended( const TaskHandle_t xTask ) PRIVILEGED_FUNCTION;
#endif /* INCLUDE_vTaskSuspend */
/*
* Utility to ready all the lists used by the scheduler. This is called
* automatically upon the creation of the first task.
*/
static void prvInitialiseTaskLists( void ) PRIVILEGED_FUNCTION;
/*
* The idle task, which as all tasks is implemented as a never ending loop.
* The idle task is automatically created and added to the ready lists upon
* creation of the first user task.
*
*/
static portTASK_FUNCTION_PROTO( prvIdleTask, pvParameters ) PRIVILEGED_FUNCTION;
#if ( configNUM_CORES > 1 )
static portTASK_FUNCTION_PROTO( prvMinimalIdleTask, pvParameters ) PRIVILEGED_FUNCTION;
#endif
/*
* Utility to free all memory allocated by the scheduler to hold a TCB,
* including the stack pointed to by the TCB.
*
* This does not free memory allocated by the task itself (i.e. memory
* allocated by calls to pvPortMalloc from within the tasks application code).
*/
#if ( INCLUDE_vTaskDelete == 1 )
static void prvDeleteTCB( TCB_t * pxTCB ) PRIVILEGED_FUNCTION;
#endif
/*
* Used only by the idle task. This checks to see if anything has been placed
* in the list of tasks waiting to be deleted. If so the task is cleaned up
* and its TCB deleted.
*/
static void prvCheckTasksWaitingTermination( void ) PRIVILEGED_FUNCTION;
/*
* The currently executing task is entering the Blocked state. Add the task to
* either the current or the overflow delayed task list.
*/
static void prvAddCurrentTaskToDelayedList( TickType_t xTicksToWait,
const BaseType_t xCanBlockIndefinitely ) PRIVILEGED_FUNCTION;
/*
* Fills an TaskStatus_t structure with information on each task that is
* referenced from the pxList list (which may be a ready list, a delayed list,
* a suspended list, etc.).
*
* THIS FUNCTION IS INTENDED FOR DEBUGGING ONLY, AND SHOULD NOT BE CALLED FROM
* NORMAL APPLICATION CODE.
*/
#if ( configUSE_TRACE_FACILITY == 1 )
static UBaseType_t prvListTasksWithinSingleList( TaskStatus_t * pxTaskStatusArray,
List_t * pxList,
eTaskState eState ) PRIVILEGED_FUNCTION;
#endif
/*
* Searches pxList for a task with name pcNameToQuery - returning a handle to
* the task if it is found, or NULL if the task is not found.
*/
#if ( INCLUDE_xTaskGetHandle == 1 )
static TCB_t * prvSearchForNameWithinSingleList( List_t * pxList,
const char pcNameToQuery[] ) PRIVILEGED_FUNCTION;
#endif
/*
* When a task is created, the stack of the task is filled with a known value.
* This function determines the 'high water mark' of the task stack by
* determining how much of the stack remains at the original preset value.
*/
#if ( ( configUSE_TRACE_FACILITY == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark == 1 ) || ( INCLUDE_uxTaskGetStackHighWaterMark2 == 1 ) )
static configSTACK_DEPTH_TYPE prvTaskCheckFreeStackSpace( const uint8_t * pucStackByte ) PRIVILEGED_FUNCTION;
#endif
/*
* Return the amount of time, in ticks, that will pass before the kernel will
* next move a task from the Blocked state to the Running state.
*
* This conditional compilation should use inequality to 0, not equality to 1.
* This is to ensure portSUPPRESS_TICKS_AND_SLEEP() can be called when user
* defined low power mode implementations require configUSE_TICKLESS_IDLE to be
* set to a value other than 1.
*/
#if ( configUSE_TICKLESS_IDLE != 0 )
static TickType_t prvGetExpectedIdleTime( void ) PRIVILEGED_FUNCTION;
#endif
/*
* Set xNextTaskUnblockTime to the time at which the next Blocked state task
* will exit the Blocked state.
*/
static void prvResetNextTaskUnblockTime( void ) PRIVILEGED_FUNCTION;
#if ( ( configUSE_TRACE_FACILITY == 1 ) && ( configUSE_STATS_FORMATTING_FUNCTIONS > 0 ) )
/*
* Helper function used to pad task names with spaces when printing out
* human readable tables of task information.
*/
static char * prvWriteNameToBuffer( char * pcBuffer,
const char * pcTaskName ) PRIVILEGED_FUNCTION;
#endif
/*
* Called after a Task_t structure has been allocated either statically or
* dynamically to fill in the structure's members.
*/
static void prvInitialiseNewTask( TaskFunction_t pxTaskCode,
const char * const pcName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */
const uint32_t ulStackDepth,
void * const pvParameters,
UBaseType_t uxPriority,
TaskHandle_t * const pxCreatedTask,
TCB_t * pxNewTCB,
const MemoryRegion_t * const xRegions ) PRIVILEGED_FUNCTION;
/*
* Called after a new task has been created and initialised to place the task
* under the control of the scheduler.
*/
static void prvAddNewTaskToReadyList( TCB_t * pxNewTCB ) PRIVILEGED_FUNCTION;
/*
* freertos_tasks_c_additions_init() should only be called if the user definable
* macro FREERTOS_TASKS_C_ADDITIONS_INIT() is defined, as that is the only macro
* called by the function.
*/
#ifdef FREERTOS_TASKS_C_ADDITIONS_INIT
static void freertos_tasks_c_additions_init( void ) PRIVILEGED_FUNCTION;
#endif
/*-----------------------------------------------------------*/
static BaseType_t prvGetCurrentYieldPending( void )
{
BaseType_t xReturn;
UBaseType_t ulState;
ulState = portDISABLE_INTERRUPTS();
xReturn = xYieldPendings[ portGET_CORE_ID() ];
portRESTORE_INTERRUPTS( ulState );
return xReturn;
}
/*-----------------------------------------------------------*/
static void prvCheckForRunStateChange( void )
{
UBaseType_t uxPrevCriticalNesting;
UBaseType_t uxPrevSchedulerSuspended;
TCB_t * pxThisTCB;
/* This should be skipped when entering a critical section within
* an ISR. If the task on the current core is no longer running, then
* vTaskSwitchContext() probably should be run before returning, but
* we don't have a way to force that to happen from here. */
if( portCHECK_IF_IN_ISR() == pdFALSE )
{
/* This function is always called with interrupts disabled
* so this is safe. */
pxThisTCB = pxCurrentTCBs[ portGET_CORE_ID() ];
while( pxThisTCB->xTaskRunState == taskTASK_YIELDING )
{
/* We are only here if we just entered a critical section
* or if we just suspended the scheduler, and another task
* has requested that we yield.
*
* This is slightly complicated since we need to save and restore
* the suspension and critical nesting counts, as well as release
* and reacquire the correct locks. And then do it all over again
* if our state changed again during the reacquisition. */
uxPrevCriticalNesting = pxThisTCB->uxCriticalNesting;
uxPrevSchedulerSuspended = uxSchedulerSuspended;
/* this must only be called the first time we enter into a critical
* section, otherwise it could context switch in the middle of a
* critical section. */
configASSERT( uxPrevCriticalNesting + uxPrevSchedulerSuspended == 1U );
uxSchedulerSuspended = 0U;
if( uxPrevCriticalNesting > 0U )
{
pxThisTCB->uxCriticalNesting = 0U;
portRELEASE_ISR_LOCK();
portRELEASE_TASK_LOCK();
}
else
{
/* uxPrevSchedulerSuspended must be 1 */
portRELEASE_TASK_LOCK();
}
portMEMORY_BARRIER();
configASSERT( pxThisTCB->xTaskRunState == taskTASK_YIELDING );
portENABLE_INTERRUPTS();
/* Enabling interrupts should cause this core to immediately
* service the pending interrupt and yield. If the run state is still
* yielding here then that is a problem. */
configASSERT( pxThisTCB->xTaskRunState != taskTASK_YIELDING );
portDISABLE_INTERRUPTS();
portGET_TASK_LOCK();
portGET_ISR_LOCK();
pxCurrentTCB->uxCriticalNesting = uxPrevCriticalNesting;
uxSchedulerSuspended = uxPrevSchedulerSuspended;
if( uxPrevCriticalNesting == 0U )
{
/* uxPrevSchedulerSuspended must be 1 */
configASSERT( uxPrevSchedulerSuspended != ( UBaseType_t ) pdFALSE );
portRELEASE_ISR_LOCK();
}
}
}
}
/*-----------------------------------------------------------*/
static void prvYieldCore( BaseType_t xCoreID )
{
/* This must be called from a critical section and
* xCoreID must be valid. */
if( portCHECK_IF_IN_ISR() && ( xCoreID == portGET_CORE_ID() ) )
{
xYieldPendings[ xCoreID ] = pdTRUE;
}
else if( pxCurrentTCBs[ xCoreID ]->xTaskRunState != taskTASK_YIELDING )
{
if( xCoreID == portGET_CORE_ID() )
{
xYieldPendings[ xCoreID ] = pdTRUE;
}
#if ( configNUM_CORES > 1 )
else
{
portYIELD_CORE( xCoreID );
pxCurrentTCBs[ xCoreID ]->xTaskRunState = taskTASK_YIELDING;
}
#endif
}
}
/*-----------------------------------------------------------*/
static void prvYieldForTask( TCB_t * pxTCB,
const BaseType_t xPreemptEqualPriority )
{
BaseType_t xLowestPriority;
BaseType_t xTaskPriority;
BaseType_t xLowestPriorityCore = -1;
BaseType_t xYieldCount = 0;
BaseType_t x;
TaskRunning_t xTaskRunState;
/* THIS FUNCTION MUST BE CALLED FROM A CRITICAL SECTION */
configASSERT( pxCurrentTCB->uxCriticalNesting > 0U );
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
{
/* No task should yield for this one if it is a lower priority
* than priority level of currently ready tasks. */
if( pxTCB->uxPriority < uxTopReadyPriority )
{
return;
}
}
#endif
xLowestPriority = ( BaseType_t ) pxTCB->uxPriority;
if( xPreemptEqualPriority == pdFALSE )
{
/* xLowestPriority will be decremented to -1 if the priority of pxTCB
* is 0. This is ok as we will give system idle tasks a priority of -1 below. */
--xLowestPriority;
}
for( x = ( BaseType_t ) 0; x < ( BaseType_t ) configNUM_CORES; x++ )
{
/* System idle tasks are being assigned a priority of tskIDLE_PRIORITY - 1 here */
xTaskPriority = ( BaseType_t ) pxCurrentTCBs[ x ]->uxPriority - pxCurrentTCBs[ x ]->xIsIdle;
xTaskRunState = pxCurrentTCBs[ x ]->xTaskRunState;
if( ( taskTASK_IS_RUNNING( xTaskRunState ) != pdFALSE ) && ( xYieldPendings[ x ] == pdFALSE ) )
{
if( xTaskPriority <= xLowestPriority )
{
#if ( configNUM_CORES > 1 )
#if ( configUSE_CORE_AFFINITY == 1 )
if( ( pxTCB->uxCoreAffinityMask & ( 1 << x ) ) != 0 )
#endif
#endif
{
#if ( configUSE_TASK_PREEMPTION_DISABLE == 1 )
if( pxCurrentTCBs[ x ]->xPreemptionDisable == pdFALSE )
#endif
{
xLowestPriority = xTaskPriority;
xLowestPriorityCore = x;
}
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) ) && 1
{
/* Yield all currently running non-idle tasks with a priority lower than
* the task that needs to run. */
if( ( ( BaseType_t ) tskIDLE_PRIORITY - 1 < xTaskPriority ) && ( xTaskPriority < ( BaseType_t ) pxTCB->uxPriority ) )
{
prvYieldCore( x );
xYieldCount++;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
#endif /* if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) ) && 1 */
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
if( ( xYieldCount == 0 ) && taskVALID_CORE_ID( xLowestPriorityCore ) )
{
prvYieldCore( xLowestPriorityCore );
xYieldCount++;
}
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
/* Verify that the calling core always yields to higher priority tasks */
if( !pxCurrentTCBs[ portGET_CORE_ID() ]->xIsIdle && ( pxTCB->uxPriority > pxCurrentTCBs[ portGET_CORE_ID() ]->uxPriority ) )
{
configASSERT( xYieldPendings[ portGET_CORE_ID() ] == pdTRUE || taskTASK_IS_RUNNING( pxCurrentTCBs[ portGET_CORE_ID() ]->xTaskRunState ) == pdFALSE );
}
#endif
}
/*-----------------------------------------------------------*/
#if ( configUSE_PORT_OPTIMISED_TASK_SELECTION == 0 )
static BaseType_t prvSelectHighestPriorityTask( const BaseType_t xCoreID )
{
UBaseType_t uxCurrentPriority = uxTopReadyPriority;
BaseType_t xTaskScheduled = pdFALSE;
BaseType_t xDecrementTopPriority = pdTRUE;
#if ( ( configNUM_CORES > 1 ) && ( configUSE_CORE_AFFINITY == 1 ) )
TCB_t * pxPreviousTCB = NULL;
#endif
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
BaseType_t xPriorityDropped = pdFALSE;
#endif
while( xTaskScheduled == pdFALSE )
{
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
{
if( uxCurrentPriority < uxTopReadyPriority )
{
/* We can't schedule any tasks, other than idle, that have a
* priority lower than the priority of a task currently running
* on another core. */
uxCurrentPriority = tskIDLE_PRIORITY;
}
}
#endif
if( listLIST_IS_EMPTY( &( pxReadyTasksLists[ uxCurrentPriority ] ) ) == pdFALSE )
{
List_t * const pxReadyList = &( pxReadyTasksLists[ uxCurrentPriority ] );
ListItem_t * pxLastTaskItem = pxReadyList->pxIndex->pxPrevious;
ListItem_t * pxTaskItem = pxLastTaskItem;
if( ( void * ) pxLastTaskItem == ( void * ) &( pxReadyList->xListEnd ) )
{
pxLastTaskItem = pxLastTaskItem->pxPrevious;
}
/* The ready task list for uxCurrentPriority is not empty, so uxTopReadyPriority
* must not be decremented any further */
xDecrementTopPriority = pdFALSE;
do
{
TCB_t * pxTCB;
pxTaskItem = pxTaskItem->pxNext;
if( ( void * ) pxTaskItem == ( void * ) &( pxReadyList->xListEnd ) )
{
pxTaskItem = pxTaskItem->pxNext;
}
pxTCB = pxTaskItem->pvOwner;
/*debug_printf("Attempting to schedule %s on core %d\n", pxTCB->pcTaskName, portGET_CORE_ID() ); */
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
{
/* When falling back to the idle priority because only one priority
* level is allowed to run at a time, we should ONLY schedule the true
* idle tasks, not user tasks at the idle priority. */
if( uxCurrentPriority < uxTopReadyPriority )
{
if( pxTCB->xIsIdle == pdFALSE )
{
continue;
}
}
}
#endif /* if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) ) */
if( pxTCB->xTaskRunState == taskTASK_NOT_RUNNING )
{
#if ( configNUM_CORES > 1 )
#if ( configUSE_CORE_AFFINITY == 1 )
if( ( pxTCB->uxCoreAffinityMask & ( 1 << xCoreID ) ) != 0 )
#endif
#endif
{
/* If the task is not being executed by any core swap it in */
pxCurrentTCBs[ xCoreID ]->xTaskRunState = taskTASK_NOT_RUNNING;
#if ( ( configNUM_CORES > 1 ) && ( configUSE_CORE_AFFINITY == 1 ) )
pxPreviousTCB = pxCurrentTCBs[ xCoreID ];
#endif
pxTCB->xTaskRunState = ( TaskRunning_t ) xCoreID;
pxCurrentTCBs[ xCoreID ] = pxTCB;
xTaskScheduled = pdTRUE;
}
}
else if( pxTCB == pxCurrentTCBs[ xCoreID ] )
{
configASSERT( ( pxTCB->xTaskRunState == xCoreID ) || ( pxTCB->xTaskRunState == taskTASK_YIELDING ) );
#if ( configNUM_CORES > 1 )
#if ( configUSE_CORE_AFFINITY == 1 )
if( ( pxTCB->uxCoreAffinityMask & ( 1 << xCoreID ) ) != 0 )
#endif
#endif
{
/* The task is already running on this core, mark it as scheduled */
pxTCB->xTaskRunState = ( TaskRunning_t ) xCoreID;
xTaskScheduled = pdTRUE;
}
}
if( xTaskScheduled != pdFALSE )
{
/* Once a task has been selected to run on this core,
* move it to the end of the ready task list. */
uxListRemove( pxTaskItem );
vListInsertEnd( pxReadyList, pxTaskItem );
break;
}
} while( pxTaskItem != pxLastTaskItem );
}
else
{
if( xDecrementTopPriority != pdFALSE )
{
uxTopReadyPriority--;
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
{
xPriorityDropped = pdTRUE;
}
#endif
}
}
/* This function can get called by vTaskSuspend() before the scheduler is started.
* In that case, since the idle tasks have not yet been created it is possible that we
* won't find a new task to schedule. Return pdFALSE in this case. */
if( ( xSchedulerRunning == pdFALSE ) && ( uxCurrentPriority == tskIDLE_PRIORITY ) && ( xTaskScheduled == pdFALSE ) )
{
return pdFALSE;
}
configASSERT( ( uxCurrentPriority > tskIDLE_PRIORITY ) || ( xTaskScheduled == pdTRUE ) );
uxCurrentPriority--;
}
configASSERT( taskTASK_IS_RUNNING( pxCurrentTCBs[ xCoreID ]->xTaskRunState ) );
#if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) )
if( xPriorityDropped != pdFALSE )
{
/* There may be several ready tasks that were being prevented from running because there was
* a higher priority task running. Now that the last of the higher priority tasks is no longer
* running, make sure all the other idle tasks yield. */
UBaseType_t x;
for( x = ( BaseType_t ) 0; x < ( BaseType_t ) configNUM_CORES; x++ )
{
if( pxCurrentTCBs[ x ]->xIsIdle != pdFALSE )
{
prvYieldCore( x );
}
}
}
#endif /* if ( ( configRUN_MULTIPLE_PRIORITIES == 0 ) && ( configNUM_CORES > 1 ) ) */
#if ( configNUM_CORES > 1 )
#if ( configUSE_CORE_AFFINITY == 1 )
if( ( pxPreviousTCB != NULL ) && ( listIS_CONTAINED_WITHIN( &( pxReadyTasksLists[ pxPreviousTCB->uxPriority ] ), &( pxPreviousTCB->xStateListItem ) ) != pdFALSE ) )
{
/* A ready task was just bumped off this core. Look at the cores it can run from
* from to see if it is able to run on any of them */
UBaseType_t uxCoreMap = pxPreviousTCB->uxCoreAffinityMask;
BaseType_t xLowestPriority = pxPreviousTCB->uxPriority - pxPreviousTCB->xIsIdle;
BaseType_t xLowestPriorityCore = -1;
if( ( uxCoreMap & ( 1 << xCoreID ) ) != 0 )
{
/* The ready task that was removed from this core is not excluded from it.
* Only look at the intersection of the cores the removed task is allowed to run
* on with the cores that the new task is excluded from. It is possible that the
* new task was only placed onto this core because it is excluded from another.
* Check to see if the previous task could run on one of those cores. */
uxCoreMap &= ~( pxCurrentTCBs[ xCoreID ]->uxCoreAffinityMask );
}