freertos: Add newlib dynamic reentrancy support

SMP FreeRTOS adds support for dynamic reentrancy in the following commit:
34b8e24d7c

This commit does the following:

- Pulls in the upstream changes
- Move __getreent() to "freertos_tasks_c_additions.h"
- Add the required configNEWLIB_REENTRANT_IS_DYNAMIC to SMP FreeRTOS port

components/freertos/FreeRTOS-Kernel-SMP/include/freertos/task.h

@@ -3180,7 +3180,7 @@ TaskHandle_t xTaskGetCurrentTaskHandle( void ) PRIVILEGED_FUNCTION;
 /*
  * Return the handle of the task running on specified core.
  */
-TaskHandle_t xTaskGetCurrentTaskHandleCPU( BaseType_t xCoreID ) PRIVILEGED_FUNCTION;
+TaskHandle_t xTaskGetCurrentTaskHandleCPU( UBaseType_t xCoreID ) PRIVILEGED_FUNCTION;
 
 /*
  * Shortcut used by the queue implementation to prevent unnecessary call to

components/freertos/FreeRTOS-Kernel-SMP/portable/xtensa/include/freertos/FreeRTOSConfig_smp.h

@@ -177,6 +177,7 @@ This file get's pulled into assembly sources. Therefore, some includes need to b
 #endif // CONFIG_FREERTOS_TLSP_DELETION_CALLBACKS
 #define configSTACK_DEPTH_TYPE                          uint32_t
 #define configUSE_NEWLIB_REENTRANT                      1
+#define configNEWLIB_REENTRANT_IS_DYNAMIC               1   // IDF Newlib supports dynamic reentrancy. We provide our own __getreent() function
 #define configENABLE_BACKWARD_COMPATIBILITY             0
 #define configASSERT(a)                                 assert(a)
 #define configINCLUDE_FREERTOS_TASK_C_ADDITIONS_H       1

components/freertos/FreeRTOS-Kernel-SMP/tasks.c

@@ -2860,17 +2860,18 @@ void vTaskStartScheduler( void )
          * starts to run. */
         portDISABLE_INTERRUPTS();
 
-        #if ( configUSE_NEWLIB_REENTRANT == 1 )
+        #if ( ( configUSE_NEWLIB_REENTRANT == 1 ) && ( configNEWLIB_REENTRANT_IS_DYNAMIC == 0 ) )
             {
                 /* 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. */
-#ifndef ESP_PLATFORM
+                 * for additional information.
+                 *
+                 * Note: Updating the _impure_ptr is not required when Newlib is compiled with
+                 * __DYNAMIC_REENT__ enabled. The port should provide __getreent() instead. */
                 _impure_ptr = &( pxCurrentTCB->xNewLib_reent );
-#endif
             }
-        #endif /* configUSE_NEWLIB_REENTRANT */
+        #endif /* ( configUSE_NEWLIB_REENTRANT == 1 ) && ( configNEWLIB_REENTRANT_IS_DYNAMIC == 0 ) */
 
         xNextTaskUnblockTime = portMAX_DELAY;
         xSchedulerRunning = pdTRUE;
@@ -3953,17 +3954,18 @@ void vTaskSwitchContext( BaseType_t xCoreID )
                 }
             #endif
 
-            #if ( configUSE_NEWLIB_REENTRANT == 1 )
+            #if ( ( configUSE_NEWLIB_REENTRANT == 1 ) && ( configNEWLIB_REENTRANT_IS_DYNAMIC == 0 ) )
                 {
                     /* 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. */
-#ifndef ESP_PLATFORM
+                     * for additional information.
+                     *
+                     * Note: Updating the _impure_ptr is not required when Newlib is compiled with
+                     * __DYNAMIC_REENT__ enabled. The the port should provide __getreent() instead. */
                     _impure_ptr = &( pxCurrentTCB->xNewLib_reent );
-#endif
                 }
-            #endif /* configUSE_NEWLIB_REENTRANT */
+            #endif /* ( configUSE_NEWLIB_REENTRANT == 1 ) && ( configNEWLIB_REENTRANT_IS_DYNAMIC == 0 ) */
         }
     }
     portRELEASE_ISR_LOCK();
@@ -4918,7 +4920,6 @@ static void prvCheckTasksWaitingTermination( void )
 
     static void prvDeleteTCB( TCB_t * pxTCB )
     {
-
         /* This call is required specifically for the TriCore port.  It must be
          * above the vPortFree() calls.  The call is also used by ports/demos that
          * want to allocate and clean RAM statically. */
@@ -5008,7 +5009,7 @@ static void prvResetNextTaskUnblockTime( void )
         return xReturn;
     }
 
-    TaskHandle_t xTaskGetCurrentTaskHandleCPU( BaseType_t xCoreID )
+    TaskHandle_t xTaskGetCurrentTaskHandleCPU( UBaseType_t xCoreID )
     {
         TaskHandle_t xReturn = NULL;
 
@@ -6440,24 +6441,3 @@ static void prvAddCurrentTaskToDelayedList( TickType_t xTicksToWait,
     #endif
 
 #endif /* if ( configINCLUDE_FREERTOS_TASK_C_ADDITIONS_H == 1 ) */
-
-/* ------------------------------------------------ IDF Compatibility --------------------------------------------------
- *
- * ------------------------------------------------------------------------------------------------------------------ */
-
-#ifdef ESP_PLATFORM
-#if ( configUSE_NEWLIB_REENTRANT == 1 )
-//Return global reent struct if FreeRTOS isn't running,
-struct _reent* __getreent(void) {
-    //No lock needed because if this changes, we won't be running anymore.
-    TCB_t *currTask=xTaskGetCurrentTaskHandle();
-    if (currTask==NULL) {
-        //No task running. Return global struct.
-        return _GLOBAL_REENT;
-    } else {
-        //We have a task; return its reentrant struct.
-        return &currTask->xNewLib_reent;
-    }
-}
-#endif
-#endif //ESP_PLATFORM

components/freertos/FreeRTOS-Kernel/tasks.c

@@ -2418,22 +2418,6 @@ void vTaskEndScheduler( void )
 }
 /*----------------------------------------------------------*/
 
-#if ( configUSE_NEWLIB_REENTRANT == 1 )
-//Return global reent struct if FreeRTOS isn't running,
-struct _reent* __getreent(void) {
-    //No lock needed because if this changes, we won't be running anymore.
-    TCB_t *currTask=xTaskGetCurrentTaskHandle();
-    if (currTask==NULL) {
-        //No task running. Return global struct.
-        return _GLOBAL_REENT;
-    } else {
-        //We have a task; return its reentrant struct.
-        return &currTask->xNewLib_reent;
-    }
-}
-#endif
-
-
 void vTaskSuspendAll( void )
 {
     /* A critical section is not required as the variable is of type

components/freertos/esp_additions/private_include/freertos_tasks_c_additions.h

@@ -17,6 +17,36 @@
  * `/additions` directory.
  */
 
+/* ----------------------------------------------------- Newlib --------------------------------------------------------
+ *
+ * ------------------------------------------------------------------------------------------------------------------ */
+
+#if ( configUSE_NEWLIB_REENTRANT == 1 )
+/**
+ * @brief Get reentrancy structure of the current task
+ *
+ * - This funciton is required by newlib (when __DYNAMIC_REENT__ is enabled)
+ * - It will return a pointer to the current task's reent struct
+ * - If FreeRTOS is not running, it will return the global reent struct
+ *
+ * @return Pointer to a the (current taks's)/(globa) reent struct
+ */
+struct _reent *__getreent(void)
+{
+    // No lock needed because if this changes, we won't be running anymore.
+    TCB_t *pxCurTask = xTaskGetCurrentTaskHandle();
+    struct _reent *ret;
+    if (pxCurTask == NULL) {
+        // No task running. Return global struct.
+        ret = _GLOBAL_REENT;
+    } else {
+        // We have a task; return its reentrant struct.
+        ret = &pxCurTask->xNewLib_reent;
+    }
+    return ret;
+}
+#endif // configUSE_NEWLIB_REENTRANT == 1
+
 /* -------------------------------------------------- Task Snapshot ----------------------------------------------------
  *
  * ------------------------------------------------------------------------------------------------------------------ */