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Generalize Thread Local Storage (TLS) support (#540)

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* Generalize Thread Local Storage (TLS) support

FreeRTOS's Thread Local Storage (TLS) support used variables and
functions from newlib, thereby making the TLS support specific to
newlib. This commit generalizes the TLS support so that it can be used
with other c-runtime libraries also. The default behavior for newlib
support is still kept same for backward compatibility.

The application writer would need to set configUSE_C_RUNTIME_TLS_SUPPORT
to 1 in their FreeRTOSConfig.h and define the following macros to
support TLS for a c-runtime library:

1. configTLS_BLOCK_TYPE - Type used to define the TLS block in TCB.
2. configINIT_TLS_BLOCK( xTLSBlock ) - Allocate and initialize memory
   block for the task's TLS Block.
3. configSET_TLS_BLOCK( xTLSBlock ) - Switch C-Runtime's TLS Block to
   point to xTLSBlock.
4. configDEINIT_TLS_BLOCK( xTLSBlock ) - Free up the memory allocated
   for the task's TLS Block.

The following is an example to support TLS for picolibc:

 #define configUSE_C_RUNTIME_TLS_SUPPORT        1
 #define configTLS_BLOCK_TYPE                   void*
 #define configINIT_TLS_BLOCK( xTLSBlock )      _init_tls( xTLSBlock )
 #define configSET_TLS_BLOCK( xTLSBlock )       _set_tls( xTLSBlock )
 #define configDEINIT_TLS_BLOCK( xTLSBlock )

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
This commit is contained in:
Gaurav-Aggarwal-AWS 2022-08-08 21:23:29 +05:30 • committed by GitHub
parent 3b18a07568
commit 95669cc1a1
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 73 additions and 41 deletions
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58
tasks.c
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@ -296,19 +296,8 @@ typedef struct tskTaskControlBlock /* The old naming convention is used to
configRUN_TIME_COUNTER_TYPE 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;
#if ( ( configUSE_NEWLIB_REENTRANT == 1 ) || ( configUSE_C_RUNTIME_TLS_SUPPORT == 1 ) )
configTLS_BLOCK_TYPE xTLSBlock; /*< Memory block used as Thread Local Storage (TLS) Block for the task. */
#endif
#if ( configUSE_TASK_NOTIFICATIONS == 1 )
@ -964,12 +953,10 @@ static void prvInitialiseNewTask( TaskFunction_t pxTaskCode,
}
#endif
#if ( configUSE_NEWLIB_REENTRANT == 1 )
#if ( ( configUSE_NEWLIB_REENTRANT == 1 ) || ( configUSE_C_RUNTIME_TLS_SUPPORT == 1 ) )
{
/* Initialise this task's Newlib reent structure.
* See the third party link http://www.nadler.com/embedded/newlibAndFreeRTOS.html
* for additional information. */
_REENT_INIT_PTR( ( &( pxNewTCB->xNewLib_reent ) ) );
/* Allocate and initialize memory for the task's TLS Block. */
configINIT_TLS_BLOCK( pxNewTCB->xTLSBlock );
}
#endif
@ -2038,15 +2025,13 @@ void vTaskStartScheduler( void )
* starts to run. */
portDISABLE_INTERRUPTS();
#if ( configUSE_NEWLIB_REENTRANT == 1 )
#if ( ( configUSE_NEWLIB_REENTRANT == 1 ) || ( configUSE_C_RUNTIME_TLS_SUPPORT == 1 ) )
{
/* Switch Newlib's _impure_ptr variable to point to the _reent
* structure specific to the task that will run first.
* See the third party link http://www.nadler.com/embedded/newlibAndFreeRTOS.html
* for additional information. */
_impure_ptr = &( pxCurrentTCB->xNewLib_reent );
/* Switch C-Runtime's TLS Block to point to the TLS
* block specific to the task that will run first. */
configSET_TLS_BLOCK( pxCurrentTCB->xTLSBlock );
}
#endif /* configUSE_NEWLIB_REENTRANT */
#endif
xNextTaskUnblockTime = portMAX_DELAY;
xSchedulerRunning = pdTRUE;
@ -3078,15 +3063,13 @@ void vTaskSwitchContext( void )
}
#endif
#if ( configUSE_NEWLIB_REENTRANT == 1 )
#if ( ( configUSE_NEWLIB_REENTRANT == 1 ) || ( configUSE_C_RUNTIME_TLS_SUPPORT == 1 ) )
{
/* Switch Newlib's _impure_ptr variable to point to the _reent
* structure specific to this task.
* See the third party link http://www.nadler.com/embedded/newlibAndFreeRTOS.html
* for additional information. */
_impure_ptr = &( pxCurrentTCB->xNewLib_reent );
/* Switch C-Runtime's TLS Block to point to the TLS
* Block specific to this task. */
configSET_TLS_BLOCK( pxCurrentTCB->xTLSBlock );
}
#endif /* configUSE_NEWLIB_REENTRANT */
#endif
}
}
/*-----------------------------------------------------------*/
@ -3958,15 +3941,12 @@ static void prvCheckTasksWaitingTermination( void )
* want to allocate and clean RAM statically. */
portCLEAN_UP_TCB( pxTCB );
/* Free up the memory allocated by the scheduler for the task. It is up
* to the task to free any memory allocated at the application level.
* See the third party link http://www.nadler.com/embedded/newlibAndFreeRTOS.html
* for additional information. */
#if ( configUSE_NEWLIB_REENTRANT == 1 )
#if ( ( configUSE_NEWLIB_REENTRANT == 1 ) || ( configUSE_C_RUNTIME_TLS_SUPPORT == 1 ) )
{
_reclaim_reent( &( pxTCB->xNewLib_reent ) );
/* Free up the memory allocated for the task's TLS Block. */
configDEINIT_TLS_BLOCK( pxCurrentTCB->xTLSBlock );
}
#endif /* configUSE_NEWLIB_REENTRANT */
#endif
#if ( ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) && ( configSUPPORT_STATIC_ALLOCATION == 0 ) && ( portUSING_MPU_WRAPPERS == 0 ) )
{