We had old arndale images working, but those were based on openSUSE-12.x which is now long obsolete and bad (e.g. missing security updates).

Thus we want to use a more modern u-boot and kernel, but those currently trigger a kernel panic. That needs to be investigated, tracked down and fixed but on the way we are hitting other problems, such as insufficient cross-compilation tools and a u-boot that can not do network/tftp boot.

Looking for hackers with the skills:

arm kernel

This project is part of:

Hack Week 13

Activity

  • over 9 years ago: bmwiedemann added keyword "arm" to this project.
  • over 9 years ago: bmwiedemann added keyword "kernel" to this project.
  • over 9 years ago: bmwiedemann started this project.
  • over 9 years ago: bmwiedemann originated this project.

  • Comments

    • bmwiedemann
      over 9 years ago by bmwiedemann | Reply

      using setenv append " init=/bin/bash" I found a workaround: echo "install xhci_hcd /bin/true" > /etc/modprobe.d/90-blacklist-xhci.conf

    • bmwiedemann
      over 9 years ago by bmwiedemann | Reply

      (ontop of modules loaded in initrd) minimal reproducer is

      for m in exynosdrm i2cs3c2410 clks2mps11 s5m8767 xhciplathcd asix ; do echo $m ; /sbin/modprobe $m ; done

    • bmwiedemann
      about 9 years ago by bmwiedemann | Reply

      still crashed with "xhci_hcd" blacklisted - but blacklisting exynosdrm helped

    Similar Projects

    Kill DMA and DMA32 memory zones by ptesarik

    Description

    Provide a better allocator for DMA-capable buffers, making the DMA and DMA32 zones obsolete.

    Goals

    Make a PoC kernel which can boot a x86 VM and a Raspberry Pi (because early RPi4 boards have some of the weirdest DMA constraints).

    Resources

    • LPC2024 talk:
    • video:


    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

    Results

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


    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.


    Model checking the BPF verifier by shunghsiyu

    Project Description

    BPF verifier plays a crucial role in securing the system (though less so now that unprivileged BPF is disabled by default in both upstream and SLES), and bugs in the verifier has lead to privilege escalation vulnerabilities in the past (e.g. CVE-2021-3490).

    One way to check whether the verifer has bugs to use model checking (a formal verification technique), in other words, build a abstract model of how the verifier operates, and then see if certain condition can occur (e.g. incorrect calculation during value tracking of registers) by giving both the model and condition to a solver.

    For the solver I will be using the Z3 SMT solver to do the checking since it provide a Python binding that's relatively easy to use.

    Goal for this Hackweek

    Learn how to use the Z3 Python binding (i.e. Z3Py) to build a model of (part of) the BPF verifier, probably the part that's related to value tracking using tristate numbers (aka tnum), and then check that the algorithm work as intended.

    Resources


    Hacking on sched_ext by flonnegren

    Description

    Sched_ext upstream has some interesting issues open for grabs:

    Goals

    Send patches to sched_ext upstream

    Also set up perfetto to trace some of the example schedulers.

    Resources

    https://github.com/sched-ext/scx