Investigate non-booting Forlinx OKMX8MX-C board (aarch64) by a_faerber

Description

In the context of a SUSE customer inquiry last year, a Forlinx OKMX8MX-C arm64 board had been relayed to me from China that a customer was not successful booting SUSE Linux Micro on. Typically this happens when the vendor's bootloader (e.g., U-Boot) is not configured properly (e.g., U-Boot's distro boot) to be compliant with Arm SystemReady Devicetree (formerly IR) band. Unfortunately I could not immediately get it to emit any output, to even diagnose why it wasn't working. There was no public documentation on the vendor's website to even confirm I was checking the right UARTs.

Earlier this year (2024) I happened to meet the ODM/OEM, Forlinx, at Embedded World 2024 in Nuremberg and again the Monday before Hackweek 24 at Electronica 2024 in Munich. The big puzzle was that the PCB print "OKMX8MX-C" does not match any current Forlinx product, there being OKMX8MM-C and OKMX8MP-C products with the Mini and Plus variants of NXP i.MX 8M family instead. One suggestion from Forlinx staff was to double-check the DIP switches on the board for boot mode selection.

Goals

Double-check the board name and investigate further what may be wrong with this board.

Resources

none

Progress

• The board name is indeed as spelled above, not matching any product on forlinx.net.
• The DIP switches were set to boot from microSD.
• Changing the DIP switches to eMMC boot did result in UART1 RS-232 output! (although at times garbled with the cable supplied and USB adapter used)
• As feared, it did not automatically load our GRUB from USB.
• Booting our GRUB manually from USB (via eMMC U-Boot commands fatload+bootefi) was unsuccessful, with partially Chinese error messages.
• This confirmed the initial suspicion, already shared with Forlinx at Embedded World 2024, that the Forlinx System-on-Module's boot firmware was not Arm SystemReady Devicetree compliant and that a firmware update would be necessary to remedy that.
• The microSD card turned out not to contain a bootable image but to only include Chinese-language board documentation (dated 20220507) and BSP files. They used a diverging name of OKMX8MQ-C.

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Create openSUSE images for Arm/RISC-V boards by avicenzi

Project Description

Create openSUSE images (or test generic EFI images) for Arm and/or RISC-V boards that are not yet supported.

Goal for this Hackweek

Create bootable images of Tumbleweed for SBCs that currently have no images available or are untested.

Consider generic EFI images where possible, as some boards can hold a bootloader.

Document in the openSUSE Wiki how to flash and use the image for a given board.

Boards that I have around and there are no images:

• Rock 3B
• Nano PC T3 Plus
• Lichee RV D1
• StartFive VisionFive (has some image needs testing)

Hack Week 22

• NanoPC T4

Hack Week 21

• NanoPi M4B
• Radxa Zero

Resources

• https://en.opensuse.org/Portal:Arm
• https://en.opensuse.org/Portal:RISC-V

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Improve UML page fault handler by ptesarik

Description

Improve UML handling of segmentation faults in kernel mode. Although such page faults are generally caused by a kernel bug, it is annoying if they cause an infinite loop, or panic the kernel. More importantly, a robust implementation allows to write KUnit tests for various guard pages, preventing potential kernel self-protection regressions.

Goals

Convert the UML page fault handler to use oops_* helpers, go through a few review rounds and finally get my patch series merged in 6.14.

Resources

Wrong initial attempt: https://lore.kernel.org/lkml/20231215121431.680-1-petrtesarik@huaweicloud.com/T/

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Modernize ocfs2 by goldwynr

Ocfs2 has gone into a stage of neglect and disrepair. Modernize the code to generate enough interest.

Goals: * Change the mount sequence to use fscontext * Move from using bufferhead to bio/folios * Use iomap * Run it through xfstests

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early stage kdump support by mbrugger

Project Description

When we experience a early boot crash, we are not able to analyze the kernel dump, as user-space wasn't able to load the crash system. The idea is to make the crash system compiled into the host kernel (think of initramfs) so that we can create a kernel dump really early in the boot process.

Goal for the Hackweeks

1. Investigate if this is possible and the implications it would have (done in HW21)
2. Hack up a PoC (done in HW22 and HW23)
3. Prepare RFC series (giving it's only one week, we are entering wishful thinking territory here).

update HW23

• I was able to include the crash kernel into the kernel Image.
• I'll need to find a way to load that from init/main.c:start_kernel() probably after kcsan_init()
• I workaround for a smoke test was to hack kexec_file_load() systemcall which has two problems:
  1. My initramfs in the porduction kernel does not have a new enough kexec version, that's not a blocker but where the week ended
  2. As the crash kernel is part of init.data it will be already stale once I can call kexec_file_load() from user-space.

The solution is probably to rewrite the POC so that the invocation can be done from init.text (that's my theory) but I'm not sure if I can reuse the kexec infrastructure in the kernel from there, which I rely on heavily.

update HW24

• Day1
  • rebased on v6.12 with no problems others then me breaking the config
  • setting up a new compilation and qemu/virtme env
  • getting desperate as nothing works that used to work
• Day 2
  • getting to call the invocation of loading the early kernel from __init after kcsan_init()

• Day 3

  • fix problem of memdup not being able to alloc so much memory... use 64K page sizes for now
  • code refactoring
  • I'm now able to load the crash kernel
  • When using virtme I can boot into the crash kernel, also it doesn't boot completely (major milestone!), crash in elfcorehdr_read_notes()

• Day 4

  • crash systems crashes (no pun intended) in copy_old_mempage() link; will need to understand elfcorehdr...
  • call path vmcore_init() -> parse_crash_elf_headers() -> elfcorehdr_read() -> read_from_oldmem() -> copy_oldmem_page() -> copy_to_iter()

• Day 5

  • hacking arch/arm64/kernel/crash_dump.c:copy_old_mempage() to see if crash system really starts. It does.
  • fun fact: retested with more reserved memory and with UEFI FW, host kernel crashes in init but directly starts the crash kernel, so it works (somehow) \o/

• TODOs

  • fix elfcorehdr so that we actually can make use of all this...
  • test where in the boot __init() chain we can/should call kexec_early_dump()

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FizzBuzz OS by mssola

Project Description

FizzBuzz OS (or just fbos) is an idea I've had in order to better grasp the fundamentals of the low level of a RISC-V machine. In practice, I'd like to build a small Operating System kernel that is able to launch three processes: one that simply prints "Fizz", another that prints "Buzz", and the third which prints "FizzBuzz". These processes are unaware of each other and it's up to the kernel to schedule them by using the timer interrupts as given on openSBI (fizz on % 3 seconds, buzz on % 5 seconds, and fizzbuzz on % 15 seconds).

This kernel provides just one system call, write, which allows any program to pass the string to be written into stdout.

This project is free software and you can find it here.

Goal for this Hackweek

• Better understand the RISC-V SBI interface.
• Better understand RISC-V in privileged mode.
• Have fun.

Resources

• SBI v2.0 ratified specification
• Blog post on SBI
• mssola/fbos

Results

The project was a resounding success Lots of learning, and the initial target was met.

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Create DRM drivers for VESA and EFI framebuffers by tdz

Description

We already have simpledrm for firmware framebuffers. But the driver is originally for ARM boards, not PCs. It is already overloaded with code to support both use cases. At the same time it is missing possible features for VESA and EFI, such as palette modes or EDID support. We should have DRM drivers for VESA and EFI interfaces. The infrastructure exists already and initial drivers can be forked from simpledrm.

Goals

• Initially, a bare driver for VESA or EFI should be created. It can take functionality from simpledrm.
• Then we can begin to add additional features. The boot loader can provide EDID data. With VGA hardware, VESA can support paletted modes or color management. Example code exists in vesafb.

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