STM32H7 - CM7 Based FreeRTOS Port

Kernel
1

Hi so I’m trying to use a CM4 Port on a CM7 MCU and I keep running into this error:

ccmG4nWC.s: Assembler messages:
ccmG4nWC.s:330: Error: selected processor does not support vstmdbeq r0!,{s16-s31}' in Thumb mode ccmG4nWC.s:332: Error: instruction not allowed in IT block -- stmdb r0!,{r4-r11,r14}’
ccmG4nWC.s:352: Error: selected processor does not support vldmiaeq r0!,{s16-s31}' in Thumb mode ccmG4nWC.s:354: Error: instruction not allowed in IT block -- msr psp,r0’
*** [.pio\build\nucleo_h743zi\libcd9\Source\portable\GCC\ARM_CM4F\port.o] Error 1

The problem is regarding the following lines in port.c:

void xPortPendSVHandler( void )
{
/* This is a naked function. */

__asm volatile
(
    "	mrs r0, psp							\n"
    "	isb									\n"
    "										\n"
    "	ldr	r3, pxCurrentTCBConst			\n"/* Get the location of the current TCB. */
    "	ldr	r2, [r3]						\n"
    "										\n"
    "	tst r14, #0x10						\n"/* Is the task using the FPU context?  If so, push high vfp registers. */
    "	it eq								\n"
    "	vstmdbeq r0!, {s16-s31}				\n"
    "										\n"
    "	stmdb r0!, {r4-r11, r14}			\n"/* Save the core registers. */
    "	str r0, [r2]						\n"/* Save the new top of stack into the first member of the TCB. */
    "										\n"
    "	stmdb sp!, {r0, r3}					\n"
    "	mov r0, %0 							\n"
    "	cpsid i								\n"/* ARM Cortex-M7 r0p1 Errata 837070 workaround. */
    "	msr basepri, r0						\n"
    "	dsb									\n"
    "	isb									\n"
    "	cpsie i								\n"/* ARM Cortex-M7 r0p1 Errata 837070 workaround. */
    "	bl vTaskSwitchContext				\n"
    "	mov r0, #0							\n"
    "	msr basepri, r0						\n"
    "	ldmia sp!, {r0, r3}					\n"
    "										\n"
    "	ldr r1, [r3]						\n"/* The first item in pxCurrentTCB is the task top of stack. */
    "	ldr r0, [r1]						\n"
    "										\n"
    "	ldmia r0!, {r4-r11, r14}			\n"/* Pop the core registers. */
    "										\n"
    "	tst r14, #0x10						\n"/* Is the task using the FPU context?  If so, pop the high vfp registers too. */
    "	it eq								\n"
    "	vldmiaeq r0!, {s16-s31}				\n"
    "										\n"
    "	msr psp, r0							\n"
    "	isb									\n"
    "										\n"
    #ifdef WORKAROUND_PMU_CM001 /* XMC4000 specific errata workaround. */
        #if WORKAROUND_PMU_CM001 == 1
            "			push { r14 }				\n"
            "			pop { pc }					\n"
        #endif
    #endif
    "										\n"
    "	bx r14								\n"
    "										\n"
    "	.align 4							\n"
    "pxCurrentTCBConst: .word pxCurrentTCB	\n"
    ::"i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY )
);

}

I was wondering if theres a CM7 Port of FreeRTOS, I havent been able to find it

edit:
I was actually able to find the CM7 Port, and I tried the port.c of the CM7 Version but I still get the same error.

edit #2:
Okay so basically with PlatformIO, In my platform.ini file. Instead of:
extra_scripts = extra.py
I did
extra_scripts = pre: extra.py

And in the extra.py is where I have my compiler flags

2

This looks more like a toolset configuration error. Are you using a sample FreeRTOS project? If not you should start with one. Which compiler are you using?

3

I’m using PlatformIO, which uses arm-none-eabi GCC 9. I basically copied the port.c from a sample project and I still get the same error

4

You need to check your compiler flags, they need to fit the platform.

5

Thank you for the heads up.
These are my current flags:
flags = [
“-mcpu=cortex-m7”,
“-std=gnu11”,
“-mfpu=fpv5-d16”,
“-mfloat-abi=hard”,
“-mthumb”,
“-u _printf_float”,
]

Could you please shed some light on how to find compiler flags for a specific platform, in this case PlatformIO?

edit: I figured it out

6

Glad to see you were able to resolve the issue! It might be helpful to others in the future if you posted what you had to change to compile successfully.