Hello,
I been struggling with this issue for a couple of days and can't manage to find the reason behind it.
About the project:
We are developing a IoT device firmware based on nRF9160 SiP. We are using first-stage immutable bootloader (MCUboot) and also LittleFS file system. System was working fine whilst it was running only on internal flash. Once we enabled external flash, we dedicated all of its memory for file logging. Since this is a multi-image build the Partition Manager is used to generate flash partitions. At the beginning the PM created MCUboot secondary image on external flash, because `CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n`by default was set to y but we changed that. At this point everything seems to be okay - MCUboot both partitions are on internal flash but filesystem is on external
The issue:
For over-the-air upgrade we use block-wise transfer and receive FW chunk by chunk from server and saved the chunk to secondary mcuboot_image slot using `flash_img_buffered_write`. After enabling external flash, flash_img_buffered_write causes secure fault which causes the system to reset. With default `partitions.yml` generated file the fault is on the first call. When I tried to add `pm_static.yml` file at some point the fault happened later but the fault still existed.
What have I tried:
I've tried creating and playing around with `pm_static.yml` file partition properties and at some point even placements but didn't manage to make it work. I also tried to replicate partitions as it was when the system worked only on internal flash just moved the littlefs_storage to external_flash partition. I have checked that when partition context passed to flash_img_buffered_write is with correct ID and address, `pm_static.yml` partition properties seems to be logical. With addr2line.exe returns that the faulting line is at `nrf_nvmc.h:378` which is a call to write a word. I tried to find a similar issue in this forum but without luck. I believe the issue is because of incorrect partitioning because at some point while I was playing with some partition properties the Secure fault was introduced only later - after couple of chunks was already saved in flash not on the first call as it is most of the time
Resources:
Here is the generated partitions.yml file which out of the box was causing secure fault on first write call
EMPTY_0:
address: 0xc000
end_address: 0x10000
placement:
before:
- mcuboot_pad
region: flash_primary
size: 0x4000
app:
address: 0x18000
end_address: 0x88000
region: flash_primary
size: 0x70000
external_flash:
address: 0x6000
end_address: 0x400000
region: external_flash
size: 0x3fa000
littlefs_storage:
address: 0x0
device: DT_CHOSEN(nordic_pm_ext_flash)
end_address: 0x6000
placement:
before:
- tfm_storage
- end
region: external_flash
size: 0x6000
mcuboot:
address: 0x0
end_address: 0xc000
placement:
before:
- mcuboot_primary
region: flash_primary
size: 0xc000
mcuboot_pad:
address: 0x10000
end_address: 0x10200
placement:
align:
start: 0x8000
before:
- mcuboot_primary_app
region: flash_primary
size: 0x200
mcuboot_primary:
address: 0x10000
end_address: 0x88000
orig_span: &id001
- app
- tfm
- mcuboot_pad
region: flash_primary
sharers: 0x1
size: 0x78000
span: *id001
mcuboot_primary_app:
address: 0x10200
end_address: 0x88000
orig_span: &id002
- app
- tfm
region: flash_primary
size: 0x77e00
span: *id002
mcuboot_secondary:
address: 0x88000
end_address: 0x100000
placement:
after:
- mcuboot_primary
align:
start: 0x8000
align_next: 0x8000
region: flash_primary
share_size:
- mcuboot_primary
size: 0x78000
mcuboot_sram:
address: 0x20000000
end_address: 0x20008000
orig_span: &id003
- tfm_sram
region: sram_primary
size: 0x8000
span: *id003
nrf_modem_lib_ctrl:
address: 0x20008000
end_address: 0x200084e8
inside:
- sram_nonsecure
placement:
after:
- tfm_sram
- start
region: sram_primary
size: 0x4e8
nrf_modem_lib_rx:
address: 0x2000a568
end_address: 0x2000c568
inside:
- sram_nonsecure
placement:
after:
- nrf_modem_lib_tx
region: sram_primary
size: 0x2000
nrf_modem_lib_sram:
address: 0x20008000
end_address: 0x2000c568
orig_span: &id004
- nrf_modem_lib_ctrl
- nrf_modem_lib_tx
- nrf_modem_lib_rx
region: sram_primary
size: 0x4568
span: *id004
nrf_modem_lib_tx:
address: 0x200084e8
end_address: 0x2000a568
inside:
- sram_nonsecure
placement:
after:
- nrf_modem_lib_ctrl
region: sram_primary
size: 0x2080
otp:
address: 0xff8108
end_address: 0xff83fc
region: otp
size: 0x2f4
sram_nonsecure:
address: 0x20008000
end_address: 0x20040000
orig_span: &id005
- sram_primary
- nrf_modem_lib_ctrl
- nrf_modem_lib_tx
- nrf_modem_lib_rx
region: sram_primary
size: 0x38000
span: *id005
sram_primary:
address: 0x2000c568
end_address: 0x20040000
region: sram_primary
size: 0x33a98
sram_secure:
address: 0x20000000
end_address: 0x20008000
orig_span: &id006
- tfm_sram
region: sram_primary
size: 0x8000
span: *id006
tfm:
address: 0x10200
end_address: 0x18000
inside:
- mcuboot_primary_app
placement:
before:
- app
region: flash_primary
size: 0x7e00
tfm_nonsecure:
address: 0x18000
end_address: 0x88000
orig_span: &id007
- app
region: flash_primary
size: 0x70000
span: *id007
tfm_secure:
address: 0x10000
end_address: 0x18000
orig_span: &id008
- mcuboot_pad
- tfm
region: flash_primary
size: 0x8000
span: *id008
tfm_sram:
address: 0x20000000
end_address: 0x20008000
inside:
- sram_secure
placement:
after:
- start
region: sram_primary
size: 0x8000
Here is my pm_static.yml file which I added based on `partitions.yml` output when everything was on internal flash.
EMPTY_0:
address: 0xc000
end_address: 0x10000
placement:
before:
- mcuboot_pad
region: flash_primary
size: 0x4000
EMPTY_1:
address: 0xf0000
end_address: 0x100000
placement:
after:
- mcuboot_secondary
region: flash_primary
size: 0x10000
app:
address: 0x18000
end_address: 0x80000
region: flash_primary
size: 0x68000
external_flash:
address: 0x6000
end_address: 0x800000
region: external_flash
size: 0x7fa000
littlefs_storage:
address: 0x0
device: DT_CHOSEN(nordic_pm_ext_flash)
end_address: 0x6000
inside:
- nonsecure_storage
placement:
before:
- end
region: external_flash
size: 0x6000
mcuboot:
address: 0x0
end_address: 0xc000
placement:
before:
- mcuboot_primary
region: flash_primary
size: 0xc000
mcuboot_pad:
address: 0x10000
end_address: 0x10200
placement:
align:
start: 0x8000
before:
- mcuboot_primary_app
region: flash_primary
size: 0x200
mcuboot_primary:
address: 0x10000
end_address: 0x80000
orig_span: &id001
- mcuboot_pad
- tfm
- app
region: flash_primary
sharers: 0x1
size: 0x70000
span: *id001
mcuboot_primary_app:
address: 0x10200
end_address: 0x80000
orig_span: &id002
- app
- tfm
region: flash_primary
size: 0x6fe00
span: *id002
mcuboot_secondary:
address: 0x80000
end_address: 0xf0000
placement:
after:
- mcuboot_primary
align:
start: 0x8000
region: flash_primary
share_size:
- mcuboot_primary
size: 0x70000
mcuboot_sram:
address: 0x20000000
end_address: 0x20008000
orig_span: &id003
- tfm_sram
region: sram_primary
size: 0x8000
span: *id003
nonsecure_storage:
address: 0x0
end_address: 0x6000
orig_span: &id004
- littlefs_storage
region: external_flash
size: 0x6000
span: *id004
nrf_modem_lib_ctrl:
address: 0x20008000
end_address: 0x200084e8
inside:
- sram_nonsecure
placement:
after:
- tfm_sram
- start
region: sram_primary
size: 0x4e8
nrf_modem_lib_rx:
address: 0x2000a568
end_address: 0x2000c568
inside:
- sram_nonsecure
placement:
after:
- nrf_modem_lib_tx
region: sram_primary
size: 0x2000
nrf_modem_lib_sram:
address: 0x20008000
end_address: 0x2000c568
orig_span: &id005
- nrf_modem_lib_ctrl
- nrf_modem_lib_tx
- nrf_modem_lib_rx
region: sram_primary
size: 0x4568
span: *id005
nrf_modem_lib_tx:
address: 0x200084e8
end_address: 0x2000a568
inside:
- sram_nonsecure
placement:
after:
- nrf_modem_lib_ctrl
region: sram_primary
size: 0x2080
otp:
address: 0xff8108
end_address: 0xff83fc
region: otp
size: 0x2f4
sram_nonsecure:
address: 0x20008000
end_address: 0x20040000
orig_span: &id006
- sram_primary
- nrf_modem_lib_ctrl
- nrf_modem_lib_tx
- nrf_modem_lib_rx
region: sram_primary
size: 0x38000
span: *id006
sram_primary:
address: 0x2000c568
end_address: 0x20040000
region: sram_primary
size: 0x33a98
sram_secure:
address: 0x20000000
end_address: 0x20008000
orig_span: &id007
- tfm_sram
region: sram_primary
size: 0x8000
span: *id007
tfm:
address: 0x10200
end_address: 0x18000
inside:
- mcuboot_primary_app
placement:
before:
- app
region: flash_primary
size: 0x7e00
tfm_nonsecure:
address: 0x18000
end_address: 0x80000
orig_span: &id008
- app
region: flash_primary
size: 0x68000
span: *id008
tfm_secure:
address: 0x10000
end_address: 0x18000
orig_span: &id009
- mcuboot_pad
- tfm
region: flash_primary
size: 0x8000
span: *id009
tfm_sram:
address: 0x20000000
end_address: 0x20008000
inside:
- sram_secure
placement:
after:
- start
region: sram_primary
size: 0x8000
Below is the output from the exception call if that helps with anything
[00:00:07.133,087] <err> os: ***** SECURE FAULT *****
[00:00:07.133,178] <err> os: Address: 0x80000
[00:00:07.133,209] <err> os: Attribution unit violation
[00:00:07.133,239] <err> os: r0/a1: 0x00080000 r1/a2: 0x96f3b83d r2/a3: 0x40039000
[00:00:07.133,270] <err> os: r3/a4: 0x80000000 r12/ip: 0x2001aac4 r14/lr: 0x0002a55b
[00:00:07.133,300] <err> os: xpsr: 0x81000000
[00:00:07.133,300] <err> os: Faulting instruction address (r15/pc): 0x0002a4a2
[00:00:07.133,422] <err> os: >>> ZEPHYR FATAL ERROR 41: Unknown error on CPU 0
[00:00:07.133,514] <err> os: Current thread: 0x2000d5b0 (unknown)
To me seems to be okay - app tries to write from non-secure region to non-secure region, the partition address's don't overlap, the partition context is correct.. Maybe somebody with a fresh pair of eyes can spot the issue right away.
EDIT: Almost forgot to mention, I am developing on a custom board but the issue can be replicated on DK. Working with SDK V2.6.0
Thanks,
Andris
