nrf5340 net core crashes when multiplying 2 uint16_t

RE: nrf5340 net core crashes when multiplying 2 uint16_t

Jocelyn Masserot — Mon, 15 Jan 2024 09:44:44 GMT

I found the issue, I was setting the option -mcpu to cortex-m33 while I should have used cortex-m33+nodsp.

Thanks for your help.

RE: nrf5340 net core crashes when multiplying 2 uint16_t

Jocelyn Masserot — Mon, 15 Jan 2024 09:22:24 GMT

Hi,

I'll try to send a full project later today. In the meantime, I've been able to narrow down the investigation. It look like the "smulbb" assembly instruction is the one causing the crash. The following code is also crashing:

__asm volatile 
(
	"ldr r0, =2\n"
	"ldr r1, =2\n"		
	"smulbb r2, r0, r1 \n"
);

Best,

Jocelyn

RE: nrf5340 net core crashes when multiplying 2 uint16_t

tesc — Fri, 12 Jan 2024 13:56:14 GMT

Hi,

Please provide the full project for reproduction, not only parts of it.

Regards,
Terje

RE: nrf5340 net core crashes when multiplying 2 uint16_t

Jocelyn Masserot — Thu, 11 Jan 2024 14:41:04 GMT

Hi, thanks for your reply.

The code is super simple. I can get the Network core to crash directly from the reset handler:

extern unsigned long _sidata;   /* start address for the initialization values of the .data section. defined in linker script */
extern unsigned long _sdata;    /* start address for the .data section. defined in linker script */
extern unsigned long _edata;    /* end address for the .data section. defined in linker script */
extern unsigned long _sbss;     /* start address for the .bss section. defined in linker script */
extern unsigned long _ebss;     /* end address for the .bss section. defined in linker script */
extern unsigned long _estack;

void Reset_Handler(void)
{
	unsigned long *src, *dest;
	
	src = &_sidata;
	
	for(dest = &_sdata; dest < &_edata; )
	{
		*(dest++) = *(src++);
	}
    
	for(dest = &_sbss; dest < &_ebss; )
	{
		*(dest++) = 0;
	}

	uint16_t temp = 2, temp2 = 4;
	temp = temp * temp2;

	main();
}

The core dump I'm getting:

error   [FAULT]: [************* Hard fault *************]                                     
error   [FAULT]: r0 = 0x4                                                                     
error   [FAULT]: r1 = 0xffffffb8                                                              
error   [FAULT]: r2 = 0x1c                                                                    
error   [FAULT]: r3 = 0x0                                                                     
error   [FAULT]: r12 = 0x2                                                                    
error   [FAULT]: lr = 0x4                                                                     
error   [FAULT]: pc = 0x1016b4f                                                               
error   [FAULT]: psr = 0x1000c0b                                                              
error   [FAULT]: icsr = 0x803                                                                 
error   [FAULT]: bfar = 0xe000ed38                                                            
error   [FAULT]: cfsr = 0x10000                                                               
error   [FAULT]: hfsr = 0x40000000                                                            
error   [FAULT]: mmfar = 0xe000ed34                                                           
error   [FAULT]: sfsr = 0x0                                                                   
error   [FAULT]: sfar = 0x0                                                                   
error   [FAULT]: [**************************************]

The observation I made so far is that the variable alignment seems to be the culprit.

Thanks,

Jocelyn

RE: nrf5340 net core crashes when multiplying 2 uint16_t

tesc — Thu, 11 Jan 2024 14:21:37 GMT

Hi,

Do you have a minimal example of this failing in a project? (That is, a full project, not only the two lines of code?) Also, do you have more details regarding the crash, such as any log, crash log, observations from a debug session, etc.?

Regards,
Terje