Add configUSE_TASK_FPU_SUPPORT to AARCH64 port

portable/GCC/ARM_AARCH64/port.c

@@ -133,6 +133,10 @@
 #define portMAX_8_BIT_VALUE                       ( ( uint8_t ) 0xff )
 #define portBIT_0_SET                             ( ( uint8_t ) 0x01 )
 
+/* The space on the stack required to hold the FPU registers.
+ * There are 32 128-bit registers.*/
+#define portFPU_REGISTER_WORDS     ( 32 * 2 )
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -244,23 +248,47 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
     *pxTopOfStack = ( StackType_t ) 0x00;         /* XZR - has no effect, used so there are an even number of registers. */
     pxTopOfStack--;
     *pxTopOfStack = ( StackType_t ) 0x00;         /* R30 - procedure call link register. */
-    pxTopOfStack--;
-
-    *pxTopOfStack = portINITIAL_PSTATE;
-    pxTopOfStack--;
 
-    *pxTopOfStack = ( StackType_t ) pxCode; /* Exception return address. */
     pxTopOfStack--;
+    *pxTopOfStack = portINITIAL_PSTATE;
 
-    /* The task will start with a critical nesting count of 0 as interrupts are
-     * enabled. */
-    *pxTopOfStack = portNO_CRITICAL_NESTING;
     pxTopOfStack--;
+    *pxTopOfStack = ( StackType_t ) pxCode; /* Exception return address. */
 
-    /* The task will start without a floating point context.  A task that uses
-     * the floating point hardware must call vPortTaskUsesFPU() before executing
-     * any floating point instructions. */
-    *pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
+    #if ( configUSE_TASK_FPU_SUPPORT == 1 )
+    {
+        /* The task will start with a critical nesting count of 0 as interrupts are
+        * enabled. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_CRITICAL_NESTING;
+
+        /* The task will start without a floating point context.  A task that
+         * uses the floating point hardware must call vPortTaskUsesFPU() before
+         * executing any floating point instructions. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
+    }
+    #elif ( configUSE_TASK_FPU_SUPPORT == 2 )
+    {
+        /* The task will start with a floating point context.  Leave enough
+         * space for the registers - and ensure they are initialised to 0. */
+        pxTopOfStack -= portFPU_REGISTER_WORDS;
+        memset( pxTopOfStack, 0x00, portFPU_REGISTER_WORDS * sizeof( StackType_t ) );
+
+        /* The task will start with a critical nesting count of 0 as interrupts are
+        * enabled. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_CRITICAL_NESTING;
+
+        pxTopOfStack--;
+        *pxTopOfStack = pdTRUE;
+        ullPortTaskHasFPUContext = pdTRUE;
+    }
+    #else /* if ( configUSE_TASK_FPU_SUPPORT == 1 ) */
+    {
+        #error "Invalid configUSE_TASK_FPU_SUPPORT setting - configUSE_TASK_FPU_SUPPORT must be set to 1, 2, or left undefined."
+    }
+    #endif /* if ( configUSE_TASK_FPU_SUPPORT == 1 ) */
 
     return pxTopOfStack;
 }
@@ -440,15 +468,19 @@ void FreeRTOS_Tick_Handler( void )
 }
 /*-----------------------------------------------------------*/
 
-void vPortTaskUsesFPU( void )
-{
-    /* A task is registering the fact that it needs an FPU context.  Set the
-     * FPU flag (which is saved as part of the task context). */
-    ullPortTaskHasFPUContext = pdTRUE;
+#if ( configUSE_TASK_FPU_SUPPORT != 2 )
 
-    /* Consider initialising the FPSR here - but probably not necessary in
-     * AArch64. */
-}
+    void vPortTaskUsesFPU( void )
+    {
+        /* A task is registering the fact that it needs an FPU context.  Set the
+         * FPU flag (which is saved as part of the task context). */
+        ullPortTaskHasFPUContext = pdTRUE;
+
+        /* Consider initialising the FPSR here - but probably not necessary in
+         * AArch64. */
+    }
+
+#endif /* configUSE_TASK_FPU_SUPPORT */
 /*-----------------------------------------------------------*/
 
 void vPortClearInterruptMask( UBaseType_t uxNewMaskValue )

portable/GCC/ARM_AARCH64/portmacro.h

@@ -135,9 +135,18 @@ extern void vPortInstallFreeRTOSVectorTable( void );
  * handler for whichever peripheral is used to generate the RTOS tick. */
 void FreeRTOS_Tick_Handler( void );
 
-/* Any task that uses the floating point unit MUST call vPortTaskUsesFPU()
- * before any floating point instructions are executed. */
-void vPortTaskUsesFPU( void );
+/* If configUSE_TASK_FPU_SUPPORT is set to 1 (or left undefined) then tasks are
+ * created without an FPU context and must call vPortTaskUsesFPU() to give
+ * themselves an FPU context before using any FPU instructions.  If
+ * configUSE_TASK_FPU_SUPPORT is set to 2 then all tasks will have an FPU context
+ * by default. */
+#if ( configUSE_TASK_FPU_SUPPORT != 2 )
+    void vPortTaskUsesFPU( void );
+#else
+    /* Each task has an FPU context already, so define this function away to
+     * nothing to prevent it from being called accidentally. */
+    #define vPortTaskUsesFPU()
+#endif
 #define portTASK_USES_FLOATING_POINT()    vPortTaskUsesFPU()
 
 #define portLOWEST_INTERRUPT_PRIORITY           ( ( ( uint32_t ) configUNIQUE_INTERRUPT_PRIORITIES ) - 1UL )