extxip_smp_srv fails compiling for nrf5340dk non-secure target

[franchan]

Hello,

Working on Ubuntu 22.04 with nRF Connect SDK 2.6.1 for the target nrf5340dk_nrf5340_cpuapp_ns (= with TF-M).

My application image became too large. I want to split the app image over internal and external memory. I'm using extxip_smp_svr as example. It compiles & runs for the target nrf5340dk_nrf5340_cpuapp.

When building this sample for the nrf5340dk_nrf5340_cpuapp_ns target (with TF-M), compilation fails:

In file included from /home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/zephyr/include/sysflash/sysflash.h:10,
                 from /home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/bootutil/src/bootutil_priv.h:33,
                 from /home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/bootutil/src/tlv.c:24:
/home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h: In function '__flash_area_ids_for_slot':
/home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:49:37: error: 'PM_MCUBOOT_PRIMARY_2_ID' undeclared (first use in this function); did you mean 'PM_MCUBOOT_PRIMARY_1_ID'?
   49 | #define FLASH_AREA_IMAGE_2_SLOTS    PM_MCUBOOT_PRIMARY_2_ID, PM_MCUBOOT_SECONDARY_2_ID
      |                                     ^~~~~~~~~~~~~~~~~~~~~~~
/home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:59:29: note: in expansion of macro 'FLASH_AREA_IMAGE_2_SLOTS'
   59 |                             FLASH_AREA_IMAGE_2_SLOTS
      |                             ^~~~~~~~~~~~~~~~~~~~~~~~
/home/dev/nrf-official/v2.6.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:67:9: note: in expansion of macro 'ALL_AVAILABLE_SLOTS'
   67 |         ALL_AVAILABLE_SLOTS
      |         ^~~~~~~~~~~~~~~~~~~

What do I need to change in this sample to make it compile for the non-secure target?

(PS my current project fails compiling with the same error when trying to add support for a split application image. That's why I looked into Nordic's sample to find how that is configured differently. Unfortunately it fails too. I saw the same error in the past when experimenting with CONFIG_BOOT_UPGRADE_ONLY=n in a multi-image build)

Thank you!

Kind regards,
francis

[franchan]

Hello,

I could solve the error described above by copying the files:
- boards/nrf5340dk_nrf5340_cpuapp.overlay
- boards/nrf5340dk_nrf5340_cpuapp.conf

as
- boards/nrf5340dk_nrf5340_cpuapp_ns.overlay
- boards/nrf5340dk_nrf5340_cpuapp_ns.conf

During linking I now run into this error:
/home/dev/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: zephyr/zephyr_pre0.elf section `bss' will not fit in region `RAM'
/home/dev/ncs/toolchains/2be090971e/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: region `RAM' overflowed by 277336 bytes
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

Is this due to the static pm_static.yml? Any suggestion on how to fix this?
Do _ns targets (TF-M) really need this amount (270k) of additional RAM (or is this a code segment overwriting the RAM segment by a large amount)?

- I've tried to move the entries from build/partitions.yml (there are new entries related to tfm) into the pm_static.yml. But the error is still the same; the RAM is still overflowed by the same amount of bytes (277336).

- I've checked the bss segment in the zephyr_pre0.elf; only 2831h

  [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
  [32] bss               NOBITS          200029e8 021a38 002831 00  WA  0   0  8

Thank you!

Kind regards,
francis

[Amanda Hsieh]

Hi, 

I suggest that you start by looking at Memory optimization and try to reduce some buffers to see if the error reports a smaller overflow. Please be aware that the nrf5340dk_nrf5340_cpuapp_ns is not listed in the Requirements of the SMP Server with external XIP sample. That means it might not be supported. 

Regards,
Amanda H. 

[franchan]

Hello Amanda,

Thank you. I will reduce a buffer and check if the size of the overflow changed later this weekend.

Meanwhile, do you mean that the technique for splitting is not supported when using non-secure target (TF-M)? Such restriction is not explicitly mentioned in the Requirements though.

I took a diff between the secure and non-secure build's "ninja partition_manager_report". But that does not show anything obviously wrong (just the expected extra 8k regions related to secure RAM):

Kind regards,
francis

[franchan]

Hello Amanda,

I have found a possible cause but dont know a workaround. Maybe you know or can ask an engineer?
The prj.conf is kept as is. Only the boards/nrf5340dk_nrf5340_cpuapp.conf and boards/nrf5340dk_nrf5340_cpuapp.overlay were duplicated in order to create a non-secure (with TF-M) target (as described above).

There is a difference in the generated linker script when building for secure compared and non-secure which explains the overflow (here's the diff):
diff build/mcuboot/zephyr/linker_zephyr_pre0.cmd build_1/mcuboot/zephyr/linker_zephyr_pre0.cmd
2c2
< _region_min_align = 32;
---
> _region_min_align = 4;
6c6
<     RAM (wx) : ORIGIN = 0x20002000, LENGTH = 0x6e000
---
>     RAM (wx) : ORIGIN = 0x20002000, LENGTH = 0x8000
234c234
<     __kernel_ram_end = 0x20002000 + 0x6e000;
---
>     __kernel_ram_end = 0x20002000 + 0x8000;

Build_1, for the nrf5340dk_nrf5340_cpuapp_ns has a much smaller RAM size. Further from the map file (build_1/mcuboot/zephyr/zephyr_pre0.map) the overflowing with 277336 bytes can be explained:

0x0000000020002000 _image_ram_start = .

... [ removed lines related to .bss and .noinit ] ...

0x000000002004db58 _image_ram_end = .

0x000000000004bb58 _image_ram_size = (_image_ram_end - _image_ram_start)

Substracting from this, the RAM size foreseen by the linker script (0x8000):
277336d = 0x46658 = 0x4bb58 - 0x8000

(Might it be related to the flash simulator?)

Apart from the wrong size, I'm also worried about the _region_min_align difference. When compiling for non-secure it is set to only "4". While the default Nordic sample has set this to 32. Can you find some clarification for this difference as well?

Kind regards,

francis

[Amanda Hsieh]

Let me check with the team and back to you when I collect enough information. 

[franchan]

Hello Amanda,
Did you or a colleague have time to further investigate this issue? Thank you!

Kind regards,
francis

[Amanda Hsieh]

We are currently understaffed due to the summer vacation period, so delayed replies must be expected. I am sorry about any inconvenience this might cause.

[franchan]

Hello Amanda,

I got one step further making compilation now succeed. I added to boards/nrf5340dk_nrf5340_cpuapp_ns.conf:
CONFIG_MCUBOOT_USE_ALL_AVAILABLE_RAM=y

However after flashing, I see an error message from the MCUBOOT:
*** Booting nRF Connect SDK v3.5.99-ncs1-1 ***
I: Starting bootloader
I: Image index: 0, Swap type: none
I: Image index: 1, Swap type: none
I: Image index: 2, Swap type: none
E: Unable to find bootable image

As a reference, when compiling without TF-M, I see the following:
I: Starting bootloader
I: Image index: 0, Swap type: none
I: Image index: 1, Swap type: none
I: Image index: 2, Swap type: none
I: Bootloader chainload address offset: 0x10000
*** Booting nRF Connect SDK v3.5.99-ncs1-1 ***


uart:~$ [00:00:00.017,639] <inf> smp_sample: build time: Jul 20 2024 13:43:51
[00:00:00.029,449] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.029,449] <inf> bt_hci_core: HW Variant: nRF53x (0x0003)
[00:00:00.029,479] <inf> bt_hci_core: Firmware: Standard Bluetooth controller (0x00) Version 54.58864 Build 1214809870
[00:00:00.031,066] <inf> bt_hci_core: Identity: E2:F6:D5:70:CD:18 (random)
[00:00:00.031,097] <inf> bt_hci_core: HCI: version 5.4 (0x0d) revision 0x218f, manufacturer 0x0059
[00:00:00.031,127] <inf> bt_hci_core: LMP: version 5.4 (0x0d) subver 0x218f
[00:00:00.033,020] <inf> smp_bt_sample: Advertising successfully started
[00:00:00.017,639] <inf> smp_sample: build time: Jul 20 2024 13:43:51
[00:00:00.029,449] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.029,449] <inf> bt_hci_core: HW Variant: nRF53x (0x0003)
[00:00:00.029,479] <inf> bt_hci_core: Firmware: Standard Bluetooth controller (0x00) Version 54.58864 Build 1214809870
[00:00:00.031,066] <inf> bt_hci_core: Identity: E2:F6:D5:70:CD:18 (random)
[00:00:00.031,097] <inf> bt_hci_core: HCI: version 5.4 (0x0d) revision 0x218f, manufacturer 0x0059
[00:00:00.031,127] <inf> bt_hci_core: LMP: version 5.4 (0x0d) subver 0x218f
[00:00:00.033,020] <inf> smp_bt_sample: Advertising successfully started

Kind regards,
francis