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UEFI L4 image?
by Peter Wiehe 26 Nov '18

26 Nov '18

Hello, can you give me a link to an UEFI flat PE image of L4Re? If that's not available, then perhaps a link to instructions how to produce one myself? Kind regards Peter

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UEFI
by Peter Wiehe 23 Nov '18

23 Nov '18

Hi everybody! Is it possible to run L4 on UEFI? Kind regards Peter Wiehe

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FOSDEM 2019 - Microkernels developer room - CfP
by Sebastian Sumpf 12 Oct '18

12 Oct '18

FOSDEM 2019 - Microkernels and Component-based OSes devroom CALL FOR PARTICIPATION The developers of several free and open-source microkernel-based operating systems will meet at FOSDEM 2019 [1] in Brussels, Belgium and will share a developer room on Sunday February 03, 2019 [2]. The devroom is currently looking for content in the form of talks and activities related to the area of microkernel-, unikernel-, and componenent-based operating systems. Possible topics include, but are not limited to: * introduction of a specific OS or framework * design of subsystems and the general architecture of an OS * enabling support for hardware (architectures, device drivers) * used languages and tools * maintenance and testing * security and robustness * trends and challenges * use cases, experiences, lessons learned and demos Please use the Pentabarf [3] system to submit your proposals. You do not need to create a new account if you already have one. When in doubt, please use the devroom mailing list [4]. If you do not want to give a talk yourself, you may still send suggestions for what else you would like to see, or do in the devroom. Please send your suggestions to the mailing list. The deadline for your proposal is on December the 1st 2018. Make sure to include the following in your proposal: * title of your talk (will be printed in the FOSDEM booklet) * your full name (will be printed in the FOSDEM booklet) * a short abstract (one or two paragraphs) * duration of your talk (please, at least 25 and no longer than 55 min) The official devroom schedule (along with the accepted talks) will be announced on December the 15th on the devroom's mailing list and the speakers will be notified via e-mail. The schedule will also be published on the FOSDEM website. About FOSDEM FOSDEM is a two-day event organised by volunteers to promote the widespread use of free and open source software. Taking place in the beautiful city of Brussels (Belgium), FOSDEM is widely recognised as the best such conference in Europe. FOSDEM covers a wide spectrum of free and open source software projects, and offers a platform for people to collaborate. To this end, FOSDEM has set up developer rooms (devrooms) with network/internet connectivity and projectors where teams can meet and showcase their projects. Devrooms are a place for teams to discuss, hack and publicly present latest directions, lightning talks, news and discussions. Besides developer rooms, FOSDEM also offers main tracks, lightning talks, certification exams and project stands. Every year, FOSDEM hosts more than 5000 developers at the ULB Solbosch campus. Participation and attendance is totally free, though the organisers gratefully accept donations and sponsorship. No registration necessary. About the devroom Since the first Microkernel devroom in 2012 this devroom has been part of each following FOSDEM. By now it has become a somewhat institutionalized tradition for the micro kernel community to meet there; to this date over a dozen projects have participated in one way or another. Each of the projects face similar challenges but come up with partially different solutions. Therefore, the goal of the Microkernel devroom is to bring the various projects together, let them exchange ideas, cross-pollinate and socialize. Social events It also has become a habit that the microkernel projects dine together somewhere in Brussels. The year 2019 will not be any different, so there is going to be a microkernel family dinner on Saturday night. We try place a reservation, so we will inform you about the exact location and time later. Consult the FOSDEM web and other projects for additional social events such as the famous FOSDEM-organized Friday Beer Event and the FOSDEM-arranged free sightseeing tours for spouses. Important dates recap * 01.12.2018: Deadline for submissions * 15.12.2018: Schedule published and speakers notified of acceptance * 03.02.2019: The devroom takes places Links [1] http://fosdem.org [2] https://fosdem.org/2019/practical/transportation [3] https://penta.fosdem.org/submission/FOSDEM19 [4] https://lists.fosdem.org/listinfo/microkernel-devroom See you all at FOSDEM!

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Information on implementing L4
by John 05 Oct '18

05 Oct '18

Hi all. I've been looking at Google and Wikipedia for information about L4, and it's fairly thin. I've come up with that L4 has read and write registers and performs IPC by fixed-length registers, with all actions synchronous (I guess that means you send a message and block until the target thread reads the message). Is there a more concrete document anywhere about implementing an L4 microkernel and what makes it L4? I'm surveying the field at the moment and looking at all the advances made in computer software—security, managed language runtimes, hypervisors, real-time OS—and trying to project the possibilities for a next-generation operating system. There's enough divergence that a rewrite from scratch might make sense; and besides, I've drawn up a method for getting a self-hosting CLR running with only anonymous memory allocation and VFS file page mapping, along with a method of getting the CLR to self-host and getting it up and running before an actual OS kernel. In other words: it's readily-achievable to write a CLR in C#, get it running on itself before the kernel comes up, then load a kernel, VMM, VFS, ABI, scheduler, and so forth—all written in C#, compiled to CIL, and totally independent of the hardware architecture underneath—and then throw away the loader and bring up init. The kernel would need to use an abstract factory model to do common tasks which require hardware-specific code, and the CLR would need to load an assembly with a concrete factory for the particular hardware and a few built-in native assembly calls; but it's doable. This is all theoretical at the moment, and I want to explore the particular edges a little to see what I find out.

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OS/Microkernel Engineers Wanted!
by Osman Ismael 02 Oct '18

02 Oct '18

[Apology for the shameless ad, but might be of interest to some] BedRock Systems is a stealth startup with a global team. Our platform is based upon cutting-edge technology, including the latest generation of L4 microkernel, and leverages the next level of development methodologies and tools. We were founded by industry veterans who built large successful companies from scratch. Our top-notch team is a mixture of the best from industry and academia. Come transform the computing landscape. Join us at www.bedrocksystems.com <http://www.bedrocksystems.com/>. BedRock Systems Engineering team.

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Call from 8-bytes aligned stack to functions that require 16-bytes stack alignment
by Yuxuan Shui 25 Sep '18

25 Sep '18

Hi, L4Linux is compiled with -mpreferred-stack-boundary=3, but the "external functions" it calls are usually compiled without this option, so defaults to 16 bytes alignment. This causes potential unaligned memory access if the compiler choose to generate instructions like movdqa. QEMU without kvm seems to just let this pass, but with kvm enabled, this could generate a GP. -- Regards Yuxuan Shui

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RE: Issues about server multi-threading on L4Re
by 李鼎基 21 Sep '18

21 Sep '18

Oh yes! Actually I used the version without arguments. Now I think I can try to fix this problem with the constructor with arguments. Thank you very much! From: Jakub Jermar<mailto:jakub.jermar@kernkonzept.com> Sent: Friday, September 21, 2018 23:12 To: 李鼎基<mailto:lidingji1997@hotmail.com> Subject: Re: Issues about server multi-threading on L4Re On 09/21/2018 05:02 PM, 李鼎基 wrote: > Actually, I’ve tried to run the server loop in only one thread (a new > thread created by “pthread_create”, NOT the main thread) on server. > > Theoretically, it should perform the same as running the server loop in > the main thread, but the server still gets stuck. How did you create your Object_registry / Registry_server - there is a version for the main thread which has constructor without arguments [0] and uses the main thread - and then there is a version with a constructor that takes arguments [1], among which is a server thread. You need to use the second version to tell it about your new thread. Can it be that you are using the version without arguments? [0] https://l4re.org/doc/classL4Re_1_1Util_1_1Registry__server.html#a694a009623… [1] https://l4re.org/doc/classL4Re_1_1Util_1_1Registry__server.html#ad88c4355e6… HTH, Jakub > > ------------------------------------------------------------------------ > *发件人:* l4-hackers <l4-hackers-bounces(a)os.inf.tu-dresden.de> 代表 > Jakub Jermar <jakub.jermar(a)kernkonzept.com> > *发送时间:* Friday, September 21, 2018 10:26:12 PM > *收件人:* l4-hackers(a)os.inf.tu-dresden.de > *主题:* Re: Issues about server multi-threading on L4Re > > Hi there! > > On 09/21/2018 02:10 PM, 李鼎基 wrote: >> I’m trying to implement some multi-threading IPC benchmarks on L4Re. >> Following the /“shared_ds”**/demo, firstly, I create 8 threads to send >> IPC on client and receive them all on server’s main thread. >> >> The server loops, waits for the requests and handles them in the >> “dispatch” function. This single-thread server works well. >> >> >> >> Then I want to create 8 threads in server (so that it can serve the >> client thread-to-thread). >> >> I wrap the “server.loop();” in a “thread_fn” and use “pthread_create” to >> create more threads, however, the server will get stuck. >> >> There are some printings after entering thread_fn so that I can make >> sure new threads are created and executed except the server.loop part. > > I guess the problem is in that you are trying to use the same server > loop for all your threads. The server loop is associated with a single > server thread that executes the server objects. In other words, all but > the thread which is associated with your server loop just block there > and don't receive any IPC calls. > >> In order to serve different requests concurrently, is there any way to >> create a multi-threading server? > > In theory (never tried that myself), you can try giving a separate > server loop to each of your threads. You will then need to register your > server object at each of them. The end result should be that your client > threads are each connected to a different IPC gate which has its own > bound server thread. All of these gates carry the label of the same > server object which will be invoked when an IPC call arrives at any of them. > > HTH, > Jakub > > -- > Kernkonzept GmbH at Dresden, Germany, HRB 31129, CEO Dr.-Ing. Michael > Hohmuth > > _______________________________________________ > l4-hackers mailing list > l4-hackers(a)os.inf.tu-dresden.de > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers -- Kernkonzept GmbH at Dresden, Germany, HRB 31129, CEO Dr.-Ing. Michael Hohmuth

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Issues about server multi-threading on L4Re
by 李鼎基 21 Sep '18

21 Sep '18

Hi, I’m trying to implement some multi-threading IPC benchmarks on L4Re. Following the “shared_ds” demo, firstly, I create 8 threads to send IPC on client and receive them all on server’s main thread. The server loops, waits for the requests and handles them in the “dispatch” function. This single-thread server works well. Then I want to create 8 threads in server (so that it can serve the client thread-to-thread). I wrap the “server.loop();” in a “thread_fn” and use “pthread_create” to create more threads, however, the server will get stuck. There are some printings after entering thread_fn so that I can make sure new threads are created and executed except the server.loop part. In order to serve different requests concurrently, is there any way to create a multi-threading server? -- Thanks

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High 32 bits of SFMASK is reserved
by Yuxuan Shui 20 Sep '18

20 Sep '18

Hi, In cpu-64.cpp, in function Cpu::setup_sysenter, Fiasco try to set IA32_FMASK (called MSR_SFMASK in the code) to ~0ULL. However, only the lower 32bit of FMASK should be written to. This cause problems on some platforms. -- Regards Yuxuan Shui

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cost (cycles + cache) of setup and use of IPC mechanisms
by Zenaan Harkness 17 Sep '18

17 Sep '18

Establishing any IPC communication channel has setup costs and per message or per "message batch" usage costs: (CPU cycles + context switches) / channel setup (CPU cycles + context switches) / msg[-batch] Further, as recent Linux kernel network stack work has discovered, cache effects strongly proscribe batch processing rather than per-msg (or per packet) processing (seems obvious, I guess "in hindsight") to make 10G and above network links work well: Batch processing of network packets https://lwn.net/Articles/763056/ and see also: User-space networking with Snabb https://lwn.net/Articles/713918/ Is there a paper quantifying and comparing various IPC mechanism costs? Specifically and separately, is there a paper quantifying the setup and use costs of shared memory IPC (possibly in comparison with any other IPC mechanism)? TIA,

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