Hot take: for critical infra, all firmware running on devices operated by public entities should be compiled and audited by these public entities.

Vendors should be required to supply source code and assist in compilation, flashing and verification; but the operator should have the means to introspect and verify any part of such deliveries independently.

Then this entire mess of a Polish train manufacturer never could have gone off the rails.

Re: https://www.ifixit.com/News/112008/polish-train-maker-is-suing-the-hackers-who-exposed-its-anti-repair-tricks

#rightToRepair #newag

@ljs @vbabka Thanks to both. Yes, I remember to read about new/concurrent/RCU friendly VMA tree at #lwn some time ago, I try fit more letters in the triangle, on the other hand R-B tree is something which students know… but showing maple can be motivation to search for more modern data structures in their future projects, I mention user-space RCU, cuckoo hashing from Knot DNS as well as others.

struct radix_tree_root	page_tree; /* radix tree of all pages */

Good catch, it seems to have gone in 4.17 kernel, when it has been renamed to

struct  radix_tree_root i_pages;

and it has been changed to struct xarray in 4.20. So this is evolution.

So it should be updated to be modern.

VPFN (virtual page frame number) and physical (P)PFN is used by me to distinguish what is view and meaning of address bits before and after MMU translation. It highlights that translation cares only about page sized frames no full addresses. It seems that it is not only mine local invention - used even on WikiBooks/The_Linux_Kernel/Memory.

The goal is to provide mainly an overall picture not details to start hacking and contributions to the kernel so if it is “roughly” appropriate is important. But if some students are attracted to contribute to Linux it would be great outcome. We have more students contributing to #NuttX which is lower bar for starting. But some have contributed drivers to Linux as well.

@ljs Congratulation to the book publication. I hope to find some time one day and look at it myself or at least, will be able to make it available to my students with help of the #cvut library.

I have plea for you and @vbabka , I prepare for the next round of the Advanced Computer Architectures course. It is focused mainly to basic knowledge about progress from pipelined execution (basic course) to the super-scalar one in nineties to understand even later designs including GPUs, NUMA, etc. But I include even some amateur glimpse how is memory used in real system which is based on my already dated wander through Linux kernel sources. I would be very happy if you find time to look at the diagram on the slide 114 of the Lecture 6 and provide me feedback if there is something which is not true or have been changed considerably so I should correct it to not mislead my students. There are some more slides around where your expert feedback can save students from misleading information as well.

Hello 🌏 ! This is #phosh's new fediverse presence. It'll have phosh's release announcements and posts/boosts of related projects. Looking forward to an interesting and bright Linux mobile future 📱 .

ICYMI: the recording of @corbet's recent #OSSNA25 talk "Three Decades in Kernelland" recently became available:

https://www.youtube.com/watch?v=hNLBGiwfBSI

From the abstract[1]: The #Linux #kernel project has been going for well over 30 years. From its beginnings on floppy diskettes and beige boxes through to its current home in pockets and unseen data centers, the kernel project has been a constant exercise in rapid development and adaptation. I have been present for almost all of the kernel project's history as an observer, contributor, maintainer, and more; all that experience will be boiled down into a fast-moving tour of how the #LinuxKernel got to where it is, what makes it successful, and what may be coming next.

[1] https://ossna2025.sched.com/event/1zfit/three-decades-in-kernelland-jonathan-corbet-lwnnet

@leonerd @oshpark @benhencke Nice option with display and local control. But if you want really cheap scopes, function generators, counters etc. then the #cvut team from another department provides firmware for cheap STM32, PICO and even Arduino (sic, some people are not willing to move forward and colleagues support them too) boards based Software Defined Instruments. For the PC side, see DataPlotter (github , with Nucleo F303RE 5 Ms/s 12 bit, STM32L412KB 2x 5 Ms/s, with Arduino 15 kS/s, with Raspberry PICO 1x 500 KS/s or 2x 250 kS/s) and older zero_elabviewer for even more boards. All firmware is available for download and documented in theses (unfortunately usually in Czech language, but colleagues or me can help).

Summer 2025 #cvut defended theses by OTREES / “my” students:

• Matyáš Bobek, FlexCAN Controller Emulation for QEMU, #qemu #canbus (git), I hope for mainlining soon, my thanks to
  @marckleinebudde for review
• Albert Bezděk, Stereo Camera FPGA Interface and Processing for Zynq Based Systems, with initial rectification and disparity in #XilinX #Zynq #FPGA (git), thank to Martin Meloun for review
• Michal Matiáš, NuttX RTOS Driver for Single Unshielded Twisted Pair Communication, working with ncv7410 and ESP32-C6 for now (nuttx, apps git), continues by #GSoC expected to lead to broader OpenAlliance SPI Ethernet MAC-PHY T1S for mainline #NuttX support after summer, thanks to @cynerd for review

See the last OTREES theses list for link to repositories and more

Another related theses from #cvut Faculty of Information Technologies mentored by Michal Štepanovský to mention:

• Jan Medek, Implementation of RISC-V soft-core processor on FPGA board with real-time operating system support, port (git) of #NuttX to the own setup of Ibex #riscv to Digilent Basys 3 and Digilent Nexys Video, includes even #NuttX, #RTEMS, #Zephyr, #FreeRTOS and RT-Thread choice analysis, some minor clarifications in my review, out of the text documentation, the student ported NuttX even to the CPU system prepared in frame of the next thesis
• Ondřej Golasowski, RISC-V open-source microarchitecture analysis and optimization, the VESP-BETA single-cycle RV32IMZicsr #riscv design for basic #comparch education with #FPGA labs

Stay tuned next summer as well, there is student interested in thesis to add MMU to #QtRvSim

@esden I am curious, what are your plans and what SW base do you intend to use? STCube, #NuttX, #Zephyr, #RTEMS or something else? May it be, there can be something in our portfolio to port or use as the example.

@brixmeister Matyáš Bobek has defended his thesis FlexCAN Controller Emulation for QEMU last Wednesday. Related git https://gitlab.fel.cvut.cz/bobekmat/qemu-flexcan. I hope that he finds time for mainlining in next month. I have submitted CTU CAN FD #CAN emulation for review to #QEMU community but it seems that FPGA support for IP cores which could be mapped into FPGA regions is not understood/welcomed yet.

We have a new home for community discussion around Yosys!

https://yosyshq.discourse.group/

Join us there for questions, support and discussion about our open source EDA tools.

Prof. Kip Thorne even presented 43 years of history leading to the proving of gravitation waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO). He has documented how this has been possible even thanks to cooperation with scientists in Prague and the Soviet Union who have been forced to withstand Stalinism, Soviet occupation of Czech Republic in 1968 ending the Prague Spring, making another obstacle for cooperation, etc. His last slide was less optimistic when compared with Prof. J. Podolský outlook ( Gravitační vlny po 10 letech, a co bude dál?) for Einstein Telescope, VIRGO, LISA, and more bright future based on cooperation of the governments, funding, and scientists worldwide.

Kip Thorne‘s lecture Quantum Fluctuations in our Universe’s Warped Side presentation at Jiří Bičák Memorial Conference 2025 organized by Charles University Faculty of Mathematics and Physics and Czech Academy of Sciences recordings are available https://youtu.be/To-vVkHHyXk

@frankenswine @LainTrain If you want to start learning #riscv ISA then the basic introduction to the minimal set of RV32 instructions can be found at our #comparch course tutorial page https://cw.fel.cvut.cz/wiki/courses/b35apo/en/tutorials/03/start .
You can test the code on the #QtRvSim single-cycle simulator setup and then follow to the pipelined version. The simulator can be installed on GNU/Linux, Windows, MAC OS and online version is available at https://comparch.edu.cvut.cz/ . The related lectures are available at https://cw.fel.cvut.cz/wiki/courses/b35apo/en/lectures/start . There are even advertisements free accessible recordings available at https://vhsky.cz/w/p/8Ejstt3Tfh8mWGcjQcEL2S

The new book how to build #riscv processor for #comparch courses is on the horizon (ETA later H2 2025) RISC-V System-on-Chip Design by D. Harris, J. Stine, R. Thompson, S. Harris. It has been presented at the RISC-V International Academic and Training SIG meeting. The recording of the session is available on YouTube https://youtu.be/Qyq5nHUDt4g The related configurable RV32I to RV64IMAFDCB core and Wally SoC sources https://github.com/openhwgroup/cvw

📣 Liberux NEXX is now live on crowdfunding! 🚀

After months of development and testing, we're introducing the most powerful Linux smartphone: RK3588S, 32 GB RAM, 5G, Debian 13 + GNOME Mobile, and total privacy with hardware killswitches. 🎉

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#LiberuxNEXX #linuxphones #privacy #opensource

Možná už tu někdo dával, ale @ppisa mě upozornil na #petici za open-source ve státní správě. Podpisů je tam pomálu a přitom petice je podle mě dobře formulovaná. Zvažte podpis. Děkuji, konec hlášení.
#gov #e-petice #opensource
https://portal.gov.cz/e-petice/1205-petice-za-povinne-zverejneni-zdrojovych-kodu-softwaru-pouzitych-ve-verejne-sprave

The #QEMU on the Linux host emulation of CAN/CAN FD bus for #nuttx presented in the article Host-Based Development with Apache NuttX – CAN Network Simulation by Mateusz Szafoni is using lot of the components from our #canbus list https://canbus.pages.fel.cvut.cz/. I have even prepared CTU CAN FD QEMU emulation variant for SoCs without PCI/PCIe bus on the branch net-can-ctucanfd-platform and my student, Matyáš Bobek has just finished his thesis adding iMX6 FlexCAN emulation into QEMU, code is available on the flexcan branch of his QEMU repository.

I am very thankful for these open-source tools as well. For my lectures and other editing, I even use the trick to render the initial combination of video, sound, and screen by Kdenlive into a raw mp4 file and then use VLC https://www.videolan.org/vlc, which is much more performant in fast searching and playback even at peed 15x. Till the speed 3.5x, it allows even to check for audio problems. Then, I use the times of the required corrections and cuts in the Kdenlive. As for the recording, I combine multiple computers running OBS, one for the camera and the other for the screen, where I usually present with BigBlueButton https://bigbluebutton.org/, which is great for making notices and drawings into PDF and other format presentations. It allows even live online access for students, which has been crucial during COVID. I use a Wacom ONE tablet https://www.wacom.com/en-us/products/pen-displays/wacom-one for annotations and drawings.
The results are available, for example, on https://vhsky.cz/c/ctucomparch/videos and the Czech Technical University in Prague YouTube channel.

If you want to learn #RiscV basic principles yourself or use it in your computer architectures #comparch basic classes, then you can use our really open and fully shared resources, no registration required for experimenting online https://comparch.edu.cvut.cz/, downloading #QtRvSim packages for all major desktop operating systems #linux, #macos, #mswidows and obtaining lectures with the sources https://cw.fel.cvut.cz/wiki/courses/b35apo/en/lectures/start and recordings on YouTube and even advertisement-free community PeerTube instance VHSky.cz. We offer even online training and and competition site https://comparch.edu.cvut.cz/online-tools/webeval/. In this case, we store SHA1 of your e-mail only for purpose to allow participants to reset their password. So again we do not intend and even cannot use your registration for advertisement for paid courses etc.