nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Mon, 10 Oct 2022 18:14:00 GMT

Newer update of the nrfxlib no longer crashes. Everything works fine so far. Advertisement implementation works both legacy 31 bytes and extended adv 255 byte. Moving on to connections stuff.

For interested parties who want to know how this works. Full source code available here :

https://github.com/IOsonata/IOsonata/blob/master/ARM/Nordic/nRF52/src/ble_app_sdc.cpp

examples firmware to advertise a counter in private data :

https://github.com/IOsonata/IOsonata/blob/master/ARM/Nordic/exemples/BleAdvertiser.cpp

This example works with both new SDC and old nRF5_SDK17.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Mon, 10 Oct 2022 07:20:19 GMT

Any chance you could provide me a minimal version of your project so I can try to replicate this here? I'm not trying to be difficult with you, but I need to have something more concrete to go on before I can involve the developers.

[quote user="hnhoan"]In this case is a hardfault[/quote]

All fault events detected by the processor will trigger the hardfault exception unless you have enabled the other fault handlers in your code (i.e. Usage fault, memory managment fault, and Bus fault).

[quote user="hnhoan"]see the LDR into an unaligned address in R3[/quote]

I do not see where the unaligned access is. The ldrb instruction shown in your screenshot is just loading a byte from memory (RAM) into r3, so this operation can't be unaligned, at least.

From the Cortex M4 Generic user Guide:

(https://developer.arm.com/documentation/dui0553/latest/)

Edit: I can't tell from the screenshots you posted what the r1 value was when the ldrb instruction was executed.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Fri, 07 Oct 2022 14:27:20 GMT

THose bits are relevant only when you get a Memfault. In this case is a hardfault. Nonetheless, it is the cause by an unalign access and have proved to you. Please stop arguing and do a code review on your side or you can send me the code. I will fix it for you.

see the LDR into an unaligned address in R3

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Fri, 07 Oct 2022 07:22:15 GMT

I'm familiar with alignment problems, but I don't see any clear indication of that being the problem here. That said, I'm not sure if I read the byte order here correctly:

[quote user="vibe"]So it appears that none of the usage fault bits are set, which means the fault is triggered by something else.[/quote]

The most significant bits belong to the usage fault status register as shown here: https://interrupt.memfault.com/blog/cortex-m-fault-debug#cfsr

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 18:34:28 GMT

[quote userid="4240" url="~/f/nordic-q-a/92617/nrfxlib-softdevice-controller-crashes-hardfault-on-nrf52832-but-not-on-nrf52840-without-zephyr-baremetal/389692"]I don’t quite understand how this can be an alignment issue. Did you check the usage fault register after the fault exception was raised?[/quote]

FYI

https://exchangetuts.com/unaligned-access-causes-error-on-arm-cortex-m4-1640371864183643

The crash was from a ldr instruction. Again this is an unaligned access fault problem.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 18:16:44 GMT

that doesn't solve the problem. you can provide me the source I'll fix it.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Thu, 06 Oct 2022 18:13:54 GMT

I suggest you go through the blog post I linked to above and try to determine what exactly triggered the the fault exception in this case.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 18:09:12 GMT

This crash only happens when optimization is enabled. When compiled with no optimization all works well. I write library code too. By experiences this type of crash always caused by un align access to global variable within a static lib.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Thu, 06 Oct 2022 18:05:28 GMT

So it appears that none of the usage fault bits are set, which means the fault is triggered by something else.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 18:02:06 GMT

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Thu, 06 Oct 2022 17:54:05 GMT

I meant this register described here: https://interrupt.memfault.com/blog/cortex-m-fault-debug#ufsr.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 17:30:09 GMT

This where it crashes

This is the registers at crash

This is register at HardFault interrupt

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Vidar Berg — Thu, 06 Oct 2022 17:18:40 GMT

I don’t quite understand how this can be an alignment issue. Did you check the usage fault register after the fault exception was raised?

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 17:11:15 GMT

It is not compiler version. I recompiled using 9.2020-q2 for you. Same problem.

I've worked with with Nordic SDK for 10 years already. I've fixed many bugs from the SDK. This time I cannot do that for you because source code is not available.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Amanda Hsieh — Thu, 06 Oct 2022 15:37:15 GMT

Hi,

[quote user="hnhoan"]We use GCC 10.3. [/quote]

Can you use GCC ARM Embedded 9.2020-q2.major this version? And you said it only happen with the optimization.

[quote user=""]Compile my code by disabling all optimization works but not when optimization is enable. The different is that when no optimization all global vars are word aligned while optimization will pack all global on a byte align. [/quote]

So I would suspect the GCC version issue. Since we havent't tested and verified with GCC 10.3, I would suggest you use the supported GCC version.

-Amanda

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 14:46:48 GMT

We are not using SES. We use GCC 10.3. It is not compiler version or IDE issue. This is in your code.

You can fix this by forcing alignment on all variable that are not unit8_t or char type or you can also enable the compiler option to allow unaligned access. By default unaligned access is not allow. That why it causes the hardfault. The draw back is that generating unaligned access the code will be slow.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Amanda Hsieh — Thu, 06 Oct 2022 14:45:03 GMT

Hi,

Which version of Segger Embedded Studio are you using? Seems like others have gotten similar errors when using too new SES version.

We always recommend using the IDE/compiler version that the SDK was tested with, this is mentioned in the SDK release notes:

nRF5 SDK v17.1.0
------------------------
Release Date: August, 2021
 
The following toolchains/devices have been used for testing and verification:
 
 - ARM: MDK-ARM version 5.25   
 - GCC: GCC ARM Embedded 9.2020-q2.major
 - IAR: IAR Workbench 7.80.4
 - SES: SES 5.42a

Regards,
Amanda

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Nguyen Hoan Hoang — Thu, 06 Oct 2022 14:32:53 GMT

The ones in the nRF5_SDK 17.1

s132_nrf52_7.2.0_softdevice.hex

s140_nrf52_7.2.0_softdevice.hex

The problem isn't the Softdevice.

I believe there are global variables that need aligned access but are not aligned using __ALIGN(x). So when compiled with optimization. Those variables become unaligned due to optimization compacting all global on a byte boundary. So you need to force those variables to be word aligned with __ALIGN(x). That was the cause of the crash inside MPSL & SDC.

RE: nrfxlib Softdevice Controller crashes (hardfault) on nRF52832 but not on nRF52840 without Zephyr (baremetal)

Amanda Hsieh — Thu, 06 Oct 2022 14:28:58 GMT

Hii,

Which version of s132 and s140 you are using? or from which version of NCS?

Regards,
Amanda