Weird issue when trying to access to uboot environment from Linux
gianluca
gianlucarenzi at eurek.it
Mon Apr 12 14:24:44 CEST 2021
Hello,
I am facing a strange/weird issue when trying to access to filesystem
based (/boot/uboot.env) in STM32MP157c-dk2 evaluation board.
Uboot is 2020.07-rc5 from github, the board DEVICETREE is
stm32mp157c-dk2, the kernel is from Robert C.Nelson repository (from
DigiKey EEWiki) and it is 5.12.0-rc6 with some patches applied during
built time.
The FSBL1 and FSBL2 and SSBL are written in the specific partitions.
The linux filesystem has 3 partitions: /boot (for kernel, devicetrees
and uboot.env) as EXT4 filesystem, / (for Debian 11 Bullseye
rootfilesystem) and /recoveryfs has a Debian 10 minimal bootstrap
configuration.
Usually UBoot is looking for the bit 2 of each partition (bootable flag)
and look for extlinux.conf configuration.
This configuration file is with a couple of entries:
> label Linux 5.12.0-rc6-armv7-lpae-x7
> kernel /vmlinuz-5.12.0-rc6-armv7-lpae-x7
> append console=ttySTM0,115200 root=/dev/mmcblk0p6 ro rootfstype=ext4 rootwait noswap mem=512M
> fdtdir /dtbs/5.12.0-rc6-armv7-lpae-x7/
> devicetree /dtbs/5.12.0-rc6-armv7-lpae-x7/stm32mp157c-dk2.dtb
> label Recovery 5.12.0-rc6-armv7-lpae-x7
> kernel /vmlinuz-5.12.0-rc6-armv7-lpae-x7
> append console=ttySTM0,115200 root=/dev/mmcblk0p5 ro rootfstype=ext4 rootwait noswap mem=512M recovery
> fdtdir /dtbs/5.12.0-rc6-armv7-lpae-x7/
> devicetree /dtbs/5.12.0-rc6-armv7-lpae-x7/stm32mp157c-dk2.dtb
Linux & Recovery.
Linux is Debian 11 Bullseye and Recovery is Debian 10 Minimal Install.
My goal at the moment is to add the ethaddr environment variable to the
/boot/uboot.env (EXT4) configuration file.
Using the u-boot tools with fw_printenv it fails with:
> # fw_printenv
> Cannot read environment, using default
> Cannot read default environment from file
The file /etc/fw_env.config has only one entry:
/boot/uboot.env 0x0000 0x4000
The file itself is 8192 bytes (0x4000 == 16384) but the fw_env.config is
(partially) wrong. I do not know if this extra information are used when
accessing a file-system-based u-boot environment anyway.
Following strace fw_printenv here is the culprit:
> execve("/usr/bin/fw_printenv", ["fw_printenv"], 0xbeaf6770 /* 20 vars */) = 0
> brk(NULL) = 0x92f000
> mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6fb2000
> access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=118003, ...}) = 0
> mmap2(NULL, 118003, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f6e000
> close(3) = 0
> openat(AT_FDCWD, "/usr/lib/arm-linux-gnueabihf/libubootenv.so.0.3", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\320\f\0\0004\0\0\0"..., 512) = 512
> fstat64(3, {st_mode=S_IFREG|0644, st_size=13784, ...}) = 0
> mmap2(NULL, 78040, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6f5a000
> mprotect(0xb6f5d000, 61440, PROT_NONE) = 0
> mmap2(0xb6f6c000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0xb6f6c000
> close(3) = 0
> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libz.so.1", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0h\32\0\0004\0\0\0"..., 512) = 512
> fstat64(3, {st_mode=S_IFREG|0644, st_size=75404, ...}) = 0
> mmap2(NULL, 139500, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6f37000
> mprotect(0xb6f49000, 61440, PROT_NONE) = 0
> mmap2(0xb6f58000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x11000) = 0xb6f58000
> close(3) = 0
> openat(AT_FDCWD, "/lib/arm-linux-gnueabihf/libc.so.6", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
> read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0Y\253\1\0004\0\0\0"..., 512) = 512
> fstat64(3, {st_mode=S_IFREG|0755, st_size=973416, ...}) = 0
> mmap2(NULL, 1042632, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6e38000
> mprotect(0xb6f22000, 61440, PROT_NONE) = 0
> mmap2(0xb6f31000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe9000) = 0xb6f31000
> mmap2(0xb6f35000, 6344, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6f35000
> close(3) = 0
> set_tls(0xb6fb3580) = 0
> mprotect(0xb6f31000, 8192, PROT_READ) = 0
> mprotect(0xb6f58000, 4096, PROT_READ) = 0
> mprotect(0xb6f6c000, 4096, PROT_READ) = 0
> mprotect(0x431000, 4096, PROT_READ) = 0
> mprotect(0xb6fb4000, 4096, PROT_READ) = 0
> munmap(0xb6f6e000, 118003) = 0
> brk(NULL) = 0x92f000
> brk(0x950000) = 0x950000
Now the interesting stuff:
> openat(AT_FDCWD, "/etc/fw_env.config", O_RDONLY) = 3
> fstat64(3, {st_mode=S_IFREG|0644, st_size=36, ...}) = 0
> read(3, "/boot/uboot.env 0x0000 0x4"..., 4096) = 36
> lstat64("/boot", {st_mode=S_IFDIR|0755, st_size=1024, ...}) = 0
> lstat64("/boot/uboot.env", {st_mode=S_IFREG|0755, st_size=8192, ...}) = 0
> stat64("/boot/uboot.env", {st_mode=S_IFREG|0755, st_size=8192, ...}) = 0
> openat(AT_FDCWD, "/boot/uboot.env", O_RDONLY) = 4
> close(4) = 0
> read(3, "", 4096) = 0
> close(3) = 0
> openat(AT_FDCWD, "/var/lock/fw_printenv.lock", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
> flock(3, LOCK_EX) = 0
> openat(AT_FDCWD, "/boot/uboot.env", O_RDONLY) = 4
> read(4, "t\310;\372\1altbootcmd=run bootcmd\0arch"..., 16384) = 8192
> close(4) = 0
> write(2, "Cannot read environment, using d"..., 39Cannot read environment, using default
> ) = 39
> openat(AT_FDCWD, "/etc/u-boot-initial-env", O_RDONLY) = -1 ENOENT (No such file or directory)
> write(2, "Cannot read default environment "..., 42Cannot read default environment from file
> ) = 42
> exit_group(-13) = ?
> +++ exited with 243 +++
What is happening here? The 16384 when reading read(4, "t\310;"...,
16384) = 8192 is correct?
Obvioulsy I do not have a /etc/u-boot-initial-env so this error is a
no-go issue.
Why I cannot read the environment?
This environment is written by u-boot itself when not finding any
previous uboot.env at the first boot.
This is FSBL1
> U-Boot SPL 2020.07-rc5 (Apr 07 2021 - 17:20:03 +0200)
> Model: STMicroelectronics STM32MP157C-DK2 Discovery Board
> RAM: DDR3-DDR3L 16bits 533000Khz
> Trying to boot from MMC1
>
>
This is SSBL (U-BOOT)
> U-Boot 2020.07-rc5 (Apr 07 2021 - 17:20:03 +0200)
>
> CPU: STM32MP157CAC Rev.B
> Model: STMicroelectronics STM32MP157C-DK2 Discovery Board
> Board: stm32mp1 in basic mode (st,stm32mp157c-dk2)
> Board: MB1272 Var2.0 Rev.C-01
> DRAM: 512 MiB
> Clocks:
> - MPU : 650 MHz
> - MCU : 208.878 MHz
> - AXI : 266.500 MHz
> - PER : 24 MHz
> - DDR : 533 MHz
> NAND: 0 MiB
> MMC: STM32 SD/MMC: 0
> Loading Environment from EXT4... ** File not found /uboot.env **
>
> ** Unable to read "/uboot.env" from mmc0:4 **
In this case there is NO uboot.env so the warning is normal.
> In: serial
> Out: serial
> Err: serial
> Net: eth0: ethernet at 5800a000
> Hit any key to stop autoboot: 0
> Boot over mmc0!
> Saving Environment to EXT4... File System is consistent
Now it saves the uboot.env with some default/board default configurations
> update journal finished
> done
> OK
update the filesystem (for journal too)
> switch to partitions #0, OK
> mmc0 is current device
> Scanning mmc 0:4...
> Found /extlinux/extlinux.conf
> Retrieving file: /extlinux/extlinux.conf
> 590 bytes read in 27 ms (20.5 KiB/s)
> 1: Linux 5.12.0-rc6-armv7-lpae-x7
Why it found only 1 entry? The file is composed by two entries as above.
> Retrieving file: /vmlinuz-5.12.0-rc6-armv7-lpae-x7
> 11526656 bytes read in 516 ms (21.3 MiB/s)
> append: console=ttySTM0,115200 root=/dev/mmcblk0p6 ro rootfstype=ext4 rootwait noswap mem=512M
> Retrieving file: /dtbs/5.12.0-rc6-armv7-lpae-x7/stm32mp157c-dk2.dtb
> 59602 bytes read in 31 ms (1.8 MiB/s)
> ## Flattened Device Tree blob at c4000000
> Booting using the fdt blob at 0xc4000000
> Loading Device Tree to cffee000, end cffff8d1 ... OK
>
> Starting kernel ...
And from now on everything is normal / as expected...
In u-boot commandline I am unable to change the uboot.env:
> STM32MP> setenv ethaddr 00:11:22:33:44:55
> ## Error: Can't overwrite "ethaddr"
> ## Error inserting "ethaddr" variable, errno=1
But uboot is able to change the environment in that partition. :-(
But it is able to add another entry (for example ethaddr0).
When trying to delete ethaddr with:
> STM32MP> setenv ethaddr 00:11:22:33:44:55
it fails with:
> ## Error: Can't overwrite "ethaddr"
> ## Error inserting "ethaddr" variable, errno=1
I tried another command:
> STM32MP> env delete ethaddr
> ## Error: Can't delete "ethaddr"
What's wrong?
My first goal is to give this board a particular mac address without
writing it on the OTP registers.
Is this possible?
Where am I wrong?
Thank you for any help you give me.
Regards,
Gianluca
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