Where is 'xMPU_SETTINGS' defined?

Kernel
1

rs9562 wrote on Tuesday, April 18, 2017:

Port is portable/GCC/ARM_CM3_MPU.
Build error (with portUSING_MPU_WRAPPERS == 1)
FreeRTOSv9.0.0/FreeRTOS/Source/include/portable.h:199:34: error: unknown type name ‘xMPU_SETTINGS’

Output from cscope for name “xMPU_SETTINGS”:
0 FreeRTOS.h 936 xMPU_SETTINGS xDummy2;

1 portable.h 199 void vPortStoreTaskMPUSettings( xMPU_SETTINGS *xMPUSettings,
const struct xMEMORY_REGION * const xRegions, StackType_t
*pxBottomOfStack, uint32_t ulStackDepth )

2 port.c 614 void vPortStoreTaskMPUSettings( xMPU_SETTINGS *xMPUSettings,
const struct xMEMORY_REGION * const xRegions, StackType_t

3 tasks.c 298 xMPU_SETTINGS xMPUSettings; /*< The MPU settings are
defined as part of the port layer. THIS MUST BE THE SECOND

2

rtel wrote on Tuesday, April 18, 2017:

When I get a ‘NNN’ undefined message the first thing I do is grep (or
equivalent) the source tree. Within a few seconds that shows me where
‘NNN’ is defined, or not as the case may be. In this case it showed me
that xMPU_SETTINGS is defined in the portmacro.h header file for the MPU
ports - so my first question back to yourself is - are you certain you
are including the correct portmacro.h file. Check the compiler options
to make sure that the path to the MPU version of portmacro.h is in the
compiler’s include path.

3

rs9562 wrote on Wednesday, April 19, 2017:

I needed to adjust the includes macro in the Makefile. I use cscope which is a glorified
grep utility. I admit that I should have checked this before posting.

Well here is the real question about the Memory Protection Unit part of the port
for the Cortex-M3. Is it as easy as making the following changes. For me the it appears
that none of the tasks start running. Otherwise, when I back out these changes below
everything runs perfectly.

FreeRTOSConfig.h:
#define portUSING_MPU_WRAPPERS 1

Makefile:
SRC += mpu_wrappers.c

4

rtel wrote on Wednesday, April 19, 2017:

FreeRTOSConfig.h:
#define portUSING_MPU_WRAPPERS 1

This is not something you should define yourself - doing so will break
the required include sequence. It is already defined in portmacro.h,
assuming you are using an MPU port so you just need to ensure you are
including the correct portmacro.h file.

Using the MPU port is definitely not as easy as a non-MPU port. I would
recommend starting with one of the pre-configured examples. There is an
example that runs in the Keil simulator (using either the ARM or GCC
compiler) that is a good place to start. If that is not in the main
FreeRTOS zip file download then you will find it in the following
directory of the SVN head:

https://sourceforge.net/p/freertos/code/HEAD/tree/trunk/FreeRTOS/Demo/CORTEX_MPU_Simulator_Keil_GCC/

There is also this one which only uses static memory allocation:

https://sourceforge.net/p/freertos/code/HEAD/tree/trunk/FreeRTOS/Demo/CORTEX_MPU_Static_Simulator_Keil_GCC/