Update the GCC Cortex-A9 port to introduce a version of the IRQ handler that saves the FPU registers.

FreeRTOS/Demo/CORTEX_A9_Zynq_ZC702/RTOSDemo/src/FreeRTOS_tick_config.c

@@ -147,7 +147,14 @@ void vClearTickInterrupt( void )
 }
 /*-----------------------------------------------------------*/
 
-void vApplicationIRQHandler( uint32_t ulICCIAR )
+/* This is the callback function which is called by the FreeRTOS Cortex-A port
+layer in response to an interrupt.  If the function is called
+vApplicationFPUSafeIRQHandler() then it is called after the floating point
+registers have been saved.  If the function is called vApplicationIRQHandler()
+then it will be called without first having saved the FPU registers.  See
+http://www.freertos.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html for
+more information */
+void vApplicationFPUSafeIRQHandler( uint32_t ulICCIAR )
 {
 extern const XScuGic_Config XScuGic_ConfigTable[];
 static const XScuGic_VectorTableEntry *pxVectorTable = XScuGic_ConfigTable[ XPAR_SCUGIC_SINGLE_DEVICE_ID ].HandlerTable;
@@ -155,7 +162,7 @@ uint32_t ulInterruptID;
 const XScuGic_VectorTableEntry *pxVectorEntry;
 
 	/* Re-enable interrupts. */
-    __asm ( "cpsie i" );
+	__asm ( "cpsie i" );
 
 	/* The ID of the interrupt is obtained by bitwise anding the ICCIAR value
 	with 0x3FF. */

FreeRTOS/Source/portable/GCC/ARM_CA9/port.c

@@ -202,6 +202,27 @@ extern void vPortRestoreTaskContext( void );
  */
 static void prvTaskExitError( void );
 
+/*
+ * If the application provides an implementation of vApplicationIRQHandler(),
+ * then it will get called directly without saving the FPU registers on
+ * interrupt entry, and this weak implementation of 
+ * vApplicationFPUSafeIRQHandler() is just provided to remove linkage errors -
+ * it should never actually get called so its implementation contains a
+ * call to configASSERT() that will always fail.
+ *
+ * If the application provides its own implementation of 
+ * vApplicationFPUSafeIRQHandler() then the implementation of 
+ * vApplicationIRQHandler() provided in portASM.S will save the FPU registers
+ * before calling it.
+ *
+ * Therefore, if the application writer wants FPU registers to be saved on
+ * interrupt entry their IRQ handler must be called 
+ * vApplicationFPUSafeIRQHandler(), and if the application writer does not want
+ * FPU registers to be saved on interrupt entry their IRQ handler must be
+ * called vApplicationIRQHandler().
+ */
+void vApplicationFPUSafeIRQHandler( uint32_t ulICCIAR ) __attribute__((weak) );
+
 /*-----------------------------------------------------------*/
 
 /* A variable is used to keep track of the critical section nesting.  This
@@ -387,7 +408,7 @@ uint32_t ulAPSR;
 		}
 	}
 
-	/* Will only get here if xTaskStartScheduler() was called with the CPU in
+	/* Will only get here if vTaskStartScheduler() was called with the CPU in
 	a non-privileged mode or the binary point register was not set to its lowest
 	possible value.  prvTaskExitError() is referenced to prevent a compiler
 	warning about it being defined but not referenced in the case that the user
@@ -555,3 +576,7 @@ uint32_t ulReturn;
 #endif /* configASSERT_DEFINED */
 /*-----------------------------------------------------------*/
 
+void vApplicationFPUSafeIRQHandler( uint32_t ulICCIAR )
+{
+	configASSERT( ( volatile void * ) NULL );
+}

FreeRTOS/Source/portable/GCC/ARM_CA9/portASM.S

@@ -289,6 +289,46 @@ switch_before_exit:
 	next. */
 	portRESTORE_CONTEXT
 
+
+/******************************************************************************
+ * If the application provides an implementation of vApplicationIRQHandler(),
+ * then it will get called directly without saving the FPU registers on
+ * interrupt entry, and this weak implementation of
+ * vApplicationIRQHandler() will not get called.
+ *
+ * If the application provides its own implementation of
+ * vApplicationFPUSafeIRQHandler() then this implementation of
+ * vApplicationIRQHandler() will be called, save the FPU registers, and then
+ * call vApplicationFPUSafeIRQHandler().
+ *
+ * Therefore, if the application writer wants FPU registers to be saved on
+ * interrupt entry their IRQ handler must be called
+ * vApplicationFPUSafeIRQHandler(), and if the application writer does not want
+ * FPU registers to be saved on interrupt entry their IRQ handler must be
+ * called vApplicationIRQHandler().
+ *****************************************************************************/
+
+.align 4
+.weak vApplicationIRQHandler
+.type vApplicationIRQHandler, %function
+vApplicationIRQHandler:
+	PUSH	{LR}
+	FMRX	R1,  FPSCR
+	VPUSH	{D0-D15}
+	VPUSH	{D16-D31}
+	PUSH	{R1}
+
+	LDR		r1, vApplicationFPUSafeIRQHandlerConst
+	BLX		r1
+
+	POP		{R0}
+	VPOP	{D16-D31}
+	VPOP	{D0-D15}
+	VMSR	FPSCR, R0
+
+	POP {PC}
+
+
 ulICCIARConst:	.word ulICCIAR
 ulICCEOIRConst:	.word ulICCEOIR
 ulICCPMRConst: .word ulICCPMR
@@ -299,6 +339,7 @@ ulMaxAPIPriorityMaskConst: .word ulMaxAPIPriorityMask
 vTaskSwitchContextConst: .word vTaskSwitchContext
 vApplicationIRQHandlerConst: .word vApplicationIRQHandler
 ulPortInterruptNestingConst: .word ulPortInterruptNesting
+vApplicationFPUSafeIRQHandlerConst: .word vApplicationFPUSafeIRQHandler
 
 .end
 

FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c

@@ -178,7 +178,7 @@ static void prvPortStartFirstTask( void ) __attribute__ (( naked ));
 /*
  * Function to enable the VFP.
  */
- static void vPortEnableVFP( void ) __attribute__ (( naked ));
+static void vPortEnableVFP( void ) __attribute__ (( naked ));
 
 /*
  * Used to catch tasks that attempt to return from their implementing function.

FreeRTOS/Source/portable/RVDS/ARM_CA9/port.c

@@ -353,7 +353,7 @@ uint32_t ulAPSR;
 		}
 	}
 
-	/* Will only get here if xTaskStartScheduler() was called with the CPU in
+	/* Will only get here if vTaskStartScheduler() was called with the CPU in
 	a non-privileged mode or the binary point register was not set to its lowest
 	possible value. */
 	return 0;