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Can L4 modules be accessed as files from L4Linux?
by Dan Haim 07 Mar '11

07 Mar '11

Hi, I'm trying to find a solution to the following scenario - I want to have an L4Linux instance running (from a CD) where the root filesystem is several hundred MB's big, so it is not feasible to run it from a ramdisk (the filesystem is larger than the amount of RAM available) - I need to run it directly from the CD. A possible solution I'm thinkning about is to give the L4Linux instance access to the CD-ROM drive, then store a SquashFS image as a file on the drive and UnionFS it with a tmpfs when the system starts. Now here's the catch - While this solution may technically work, it is still not 'good enough' because I can't give the L4Linux instance direct access to the CD-ROM drive - I need to have it completely isolated so a user working on the L4Linux instance will not have access to any files stored on the CD (other than the SquashFS image) even if he/she has root access over the L4Linux instance. I was thinking - is it possible to specify the SquashFS image as an L4 module and then somehow mount it from within L4Linux in-place (i.e. without completely loading it to RAM)? Is there any other way to accomplish what's needed in this scenario? Thank you all, Dan.

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Genode OS framework and kernel-specific features
by Valery V. Sedletski 05 Mar '11

05 Mar '11

Hi all. I am now giving a try to the Genode OS framework. I like it's concepts and ideas and its elegant design, and maybe, will migrate to it eventually. -- I was developing an OS/2 clone based on Fiasco microkernel and l4env. Now they're discontinued. So, I must probably, migrate to something else. The most probable candidates are L4Re or Genode. I like Genode because of its kernel-neutrality (It can work on any L4 flavour, it is very attractive feature) and has interesting ideas regarding the scalability and capability to build a hierarchy of subsystems, minimising the application-specific Trusted Computing Bases. So, as I understood, it abstracts the kernel specifics from a developer. But in some cases, it can be desirable to make some kernel-specific implementations. For example, Fiasco kernel based on l4v2 API has 'segments' feature which, for example, is actively used by L4Linux. We use this feature too. One of our objectives is a binary compatibility with existing OS/2 applications. And OS/2 application ABI includes a convention that FS register for Ring3 application, holds a selector of a structure named Thread Info Block. Though the application can obtain this structure by calling an DosGetInfoBlocks() API, the C startup code generated by many compilers, relies on the convention that FS must contain the TIB selector. So, if we try to implement this feature on L4, we must have the means to allocate GDT selectors and get the allocated selector. On Fiasco, this can be done by filling the registers in a special way and issuing a 'LLDT' instruction, or, by calling a fiasco_gdt_set() function, and get the allocated selector by fiasco_gdt_get_entry_offset() (which is the same, but through a 'l4sys' package). On Fiasco.OC, this can be done similar way (not through LLDT instruction, though). My question is: Can be the underlying kernel determined under Genode, and then try doing kernel-specific things? Or, maybe, there is a more elegant way to do kernel-specific things? Thanks in advance, valery. PS: On Pistachio, as I heard, the application also can operate on GDT selectors, but this possibility has even more limitations. (It seems, only LDT selectors can be altered, but not GDT ones, or something)

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Compiling l4re for BeagleBoard
by Ivan Bludov 04 Mar '11

04 Mar '11

Hello, I'm trying to compile l4re for ARM (beagleboard). I used the cross-toolchain for AMR (from CodeSourcery and toolchain downloaded from your site), but I got errors during making configuration of l4 : =========================================================== set -e; X="tmp.$$$RANDOM.c" ; echo 'int main(void){}'>$X ; \ rm -f $X.out ; LD_PRELOAD=libgendep.so LD_LIBRARY_PATH=/home/ibludov/Downloads/l4re-snapshot-2011022209.0/src/l4/build/tool/gendep/64: GENDEP_SOURCE=$X \ GENDEP_OUTPUT=$X.out arm-linux-gcc -c $X -o $X.o; \ test -e $X.out; echo INT_CPP_NAME=`cat $X.out` \ >>/home/ibludov/Downloads/l4re-snapshot-2011022209.0/src/l4/build/.config.all; \ rm -f $X $X.{o,out}; ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ============================================================ These errors appear only when I use the arm-linux compiler and do not appear when I use host compiler. Is it a problem of toolchan or some other system libraries? Can you make some advise to fix it? Ivan Bludov

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thread creation help
by Jason Philip 27 Feb '11

27 Feb '11

Can someone tell me how to create a thread (in the same address space as the creating thread)? This very confusing to me, I need help.

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Announcement: Genode 11.02 with support for both NOVA v0.3 and Fiasco.OC
by Norman Feske 24 Feb '11

24 Feb '11

Dear L4 hackers, I am pleased to announce the release of the version 11.02 of the Genode OS Framework. Genode is an OS architecture that promises to align high security and robustness with dynamic application workloads. The Genode OS Framework as the reference implementation of this architecture. With the new version 11.02, we enabled the framework to be used with the Fiasco.OC kernel developed at TU Dresden in addition to the already supported base platforms L4/Fiasco, L4ka::Pistachio, Linux, OKL4v2, Codezero, and NOVA. Furthermore, we upgraded the NOVA support to version 0.3, which was published earlier this month. So now, both current kernel developments at TU Dresden are fully embraced by the framework. We are grateful for the excellent support we got from Alexander Warg and Udo Steinberg. Alongside the expanded platform support, the new release features many improvements, the most prominent being - Fiasco.OC as new base platform - Running Genode natively on MicroBlaze CPUs - Support for version 0.3 of the NOVA hypervisor - Noux execution environment for GNU userland software - Base framework - Core resource accounting using guarded allocators - Protocol enhancements for upgrading session quotas - Qt4 updated to version 4.7.1 - New tooling support for automated integration and testing Please find a more elaborative description of the changes accompanied with a lot of background information in the release notes of version 11.02: http://genode.org/documentation/release-notes/11.02 The new version is ready for download at our download page at Sourceforge and our public SVN repository: http://genode.org/download Best Regards -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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L4Re: C++ or DICE for IPC
by Valery V. Sedletski 24 Feb '11

24 Feb '11

Hi, all. I checked out a new L4Re userland and a new Fiasco.OC microkernel. I noticed that it seems, no IDL compiler is used for IPC anymore, but found that, like in l4\pkg\examples\clntsrv\ example, IPC is encapsulated in C++ classes. That's nice, C++ is a feature-rich object oriented language. But what can I do if I want to write a program on other languages, like plain C, Ada etc.? I think, such possibility must exist too, and IDL is a means of implementing such a language neutrality. Is DICE discontinued? And how can I do something with communication code if not using IDL? Thanks in advance, WBR, valery

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Boot into video mode with grub2
by Dan Haim 23 Feb '11

23 Feb '11

Hi, I'm trying to boot L4Linux under MAG. I used to use the "vbeset 0x117" GRUB command to set the screen into the correct video mode but now I'm using GRUB2 and I can't find any equivalent command(s). Has anyone successfully booted MAG under GRUB2?

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[L4 on realview Cortex A9] Failing on board check during fiasco bootup
by Naveen Chandrakar 23 Feb '11

23 Feb '11

Hello Guys, I was attempting to run fiasco built for CortexA9/realview-pbx board on qemu. "qemu-system-arm" version used for this experimentation is "QEMU PC emulator version 0.12.5 (qemu-kvm-0.12.5)" L4 Code used "l4re-core-2011020417" with hello world example. Below are the messages which i got when i tried to run fiasco on qemu - 1st set of logs I tried to comment the check inside Board_check::check_board() in the hope that it might boot up, but later i got crash for qemu (hw mismatch ?) - 2nd set of logs *1st set of logs* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ L4 msgs specifying invalid sys id~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ novino@naveen-linux:~/L4/l4re-core-2011020417/src/l4/mybuild-realview-pbx-a9/images$ qemu-system-arm -M realview-pbx-a9 -cpu cortex-a9 -kernel bootstrap_hello.elf -m 256 -nographic -net nic -net user L4 Bootstrapper Build: #2 Thu Feb 10 18:21:42 MVT 2011, 4.5.1 Scanning up to 256 MB RAM ........some messages ..... Starting kernel fiasco at 00001000 Cache config: ON Realview System ID: Rev=0 HBI=178 Build=0 Arch=5 FPGA=00 Invalid System ID for this kernel config Expected (01780500 & ffffff00) == 1182f500 Stopping. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ end of msgs ~~~~~~~~~~~~~~~~~~~~~ *2nd Set of logs* ~~~~~~~~~~~~~~~~~~~ L4 msgs after modifying Board_check::check_board() ~~~~~~~~~~~~~~~~~~~~~~~~ novino@naveen-linux:~/L4/l4re-core-2011020417/src/l4/mybuild-realview-pbx-a9/images$ qemu-system-arm -M realview-pbx-a9 -cpu cortex-a9 -kernel bootstrap_hello.elf -m 256 -nographic -net nic -net user L4 Bootstrapper Build: #3 Thu Feb 10 19:06:41 MVT 2011, 4.5.1 Scanning up to 256 MB RAM Memory size is 256MB (00000000 - 10000000) RAM: 0000000000000000 - 000000000fffffff: 262144kB Total RAM: 256MB mod04: 010d3000-010f4450: hello mod03: 010b1000-010d2488: l4re mod02: 01073000-010b066c: moe mod01: 01061000-01072304: sigma0 mod00: 01015000-010608f8: fiasco Moving 5 modules to 1100000 with offset eb000 moving module 05 { 10d3000-10f4450 } -> { 11be000-11df450 } moving module 04 { 10b1000-10d2488 } -> { 119c000-11bd488 } moving module 03 { 1073000-10b066c } -> { 115e000-119b66c } moving module 02 { 1061000-1072304 } -> { 114c000-115d304 } moving module 01 { 1015000-10608f8 } -> { 1100000-114b8f8 } Scanning fiasco Scanning sigma0 Scanning moe --init=rom/hello Relocated mbi to [0x100f000-0x100f0d6] Loading fiasco Loading sigma0 Loading moe find kernel info page... found kernel info page at 0x2000 Regions of list regions [ 1000, 19ff] { a00} Kern fiasco [ 2000, 5cfff] { 5b000} Kern fiasco [ 90000, 9e193] { e194} Sigma0 sigma0 [ 140000, 18b48b] { 4b48c} Root moe [ 1000000, 10143eb] { 143ec} Boot bootstrap [ 100f000, 100f1d3] { 1d4} Root Multiboot info [ 119c000, 11df44f] { 43450} Root Modules Memory API Version: (87) experimental Sigma0 config ip:00090000 sp:01013044 Roottask config ip:00140088 sp:00000000 Starting kernel fiasco at 00001000 Cache config: ON Realview System ID: Rev=0 HBI=178 Build=0 Arch=5 FPGA=00 <<Commented>> Invalid System ID for this kernel config Expected (01780500 & ffffff00) == 1182f500 Stopping. Hello from Startup::stage2 Initialize page table Number of IRQs available at this GIC: 96 Number of IRQs available at this GIC: 32 Vmem_alloc::init() qemu: fatal: Unimplemented cp15 register write (c9, c14, {0, 0}) R00=00000000 R01=00000000 R02=80000000 R03=00000001 R04=f00487b0 R05=00054004 R06=00215406 R07=00115406 R08=00015406 R09=00002000 R10=00000000 R11=0100f058 R12=ffffffff R13=f0048670 R14=f005bd3c R15=f005bd28 PSR=a00001d3 N-C- A svc32 Aborted ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~end of msgs ~~~~~~~~~~~~~~~~~~~~~~~~ Warm Regards, Naveen

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13th Real Time Linux Workshop - 1st Call for Papers
by Nicholas Mc Guire 23 Feb '11

23 Feb '11

Hi ! would be nice if we could get an update of the current L4 activities for at the next RTLWS - CfP bellow. thx! hofrat 13th Real-Time Linux Workshop October 20-22, 2011 Faculty of Electrical Engineering Czech Technical University in Prague Prague, Czech Republic Following the meetings of academics, developers and users of real-time and embedded Linux at the previous 12 real-time Linux workshops held world-wide (Vienna, Orlando, Milano, Boston, Valencia, Singapore, Lille, Lanzhou, Linz, Guadalajara, Dresden and Nairobi), the Real-Time Linux Workshop for 2011 will come to the Czech Technical University in Prague, Faculty of Electrical Engineering, Dept. of Control Engineering - academic OSADL member since 2008. The workshop will be held from October 20 to 22. Rationale Embedded and real-time Linux are gaining traction in consumer electronics and in industrial computing in breath-taking speed. Linux runs a wide range of industrial applications including real-time and safety-related systems. And the best is that everyone on earth has access to this unparalleled pool of Open Source software as long as he or she has access to the Internet. Nevertheless, this access is by no means one-way - the return paths are from providing bug reports, additions and ideas for enhancements and, finally, the very important mechanism of peer review that makes Linux, and particularly real-time Linux, as stable and innovative as it is. In addition to sending patches and providing feedback via Internet, direct mutual exchange between field engineers, system integrators, and project managers, and hardware, driver, board support package and kernel developers is needed. The Real Time Linux Workshop is successfully serving this purpose since more than 10 years. We are looking forward to meeting each other at another great Real Time Linux Workshop - this time in Prague, Czech Republic. Call for papers Authors from academics, industry as well as the user community are invited to submit papers on original work related to Open Source real-time systems. Such work may deal with general topics related to Open Source based real-time systems but also with research, experiments and case studies, as well as with issues of integration of Open Source real-time and embedded systems. A special focus will be on industrial case studies and safety-related systems. Topics of interest include, but are not limited to: - Modifications and variants of the GNU/Linux operating systems extending its real-time capabilities - Contributions to real-time Linux variants, drivers and extensions - User-mode real-time concepts, implementation and experience - Real-time Linux applications, in academia, research and industry - Safety-related FLOSS systems - Work in progress reports, covering recent developments - Educational material on real-time Linux - Tools for embedding Linux or real-time Linux and embedded real-time Linux applications - RTOS core concepts, RT-safe synchronization mechanisms - RT-safe interaction of RT and non RT components - IPC mechanisms in RTOS - Analysis and benchmarking methods and results of real-time GNU/Linux variants - Real-time networking with COTS - Medical applications using COTS and FLOSS - Debugging techniques and tools, both for code and temporal debugging of core RTOS components, drivers and real-time applications - Real-time related extensions to development environments Abstract submission If you wish to present a paper at the workshop, please submit an abstract using the submission page at https://www.osadl.org/RTLWS13-Abstract.submission-form.0.html. Final paper to be included into the RTLWS13 Proceedings Upon acceptance of an abstract by the RTLWS13 Program Committee, the author will be invited to submit a full paper in a form defined by https://www.osadl.org/paper.tgz. A detailed description of the editing and formatting process will be provided along with the notification email. Important dates - Release of this Call for Papers on February 22, 2011 - Second Call for Papers on May 3, 2011 - Third Call for Papers on May 31, 2011 - Deadline for abstract submission on June 13, 2011 - Notification upon acceptance by July 8, 2011 - Paper submission deadline on September 5, 2011 - RTLWS13 from October 20 to 22, 2011 - LinuxCon Europe in Prague from October 26 to 28, 2011 - Embedded Linux Conference (ELC) Europe in Prague from October 26 to 28, 2011 For more information about the Czech Technical University in Prague, the organizers and the members of the program committee, please refer to the RTLWS13 Homepage at osadl.org/RTLWS. The Organization committee Local staff at the Czech Technical University Prague - Michal Sojka (Faculty of Electrical Engineering, Department of Control Engineering) - Pavel Pisa (Faculty of Electrical Engineering, Department of Control Engineering) - Petr Hodac (SUT - Stredisko un*xovych technologii, UN*X Technologies Center) Real-Time Linux Foundation Working Group and OSADL - Nicholas Mc Guire (Distributed and Embedded Systems Lab, Lanzhou University, China) - Qingguo Zhou (Distributed and Embedded Systems Lab, Lanzhou University, China) - Andreas Platschek (Opentech, Austria) - Carsten Emde (OSADL, Germany)

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A few general questions about L4
by Maciej Katafiasz 22 Feb '11

22 Feb '11

Hello, I'm currently investigating L4 as the platform on which to base an OS I'm considering writing, and for this reason I have several more or less specific questions to help me get oriented in the whole L4 ecosystem. As a matter of introduction, the OS I have in mind is a modern incarnation of a Lisp Machine (http://en.wikipedia.org/wiki/Lisp_machine) attempting to marry the good parts of LispM's such as hackability and the ability to inspect and touch the OS on any level, without their problems (such as the great ease of _crashing_ the OS by mistake, and their inherent lack of security and compartmentalisation). The OS is intended to be practical, and I'm greatly interested in preserving compatibility with existing software, and the ability to mix Lisp apps with C libraries and vice-versa. The practicality requirement also means that I want to avoid writing everything I can avoid writing, in particular drivers. With this being said, here are my initial questions: * Which implementations are currently considered active and sufficient for basing new efforts on? I know Fiasco.OC, seL4, OKL4 and L4Ka. Out of these, seL4 and OKL4 are closed-source and proprietary, thus not really suitable for my needs. Fiasco.OC seems active, L4Ka somewhat less so, with last full release from 2004 (although the last commit to Hg seems to be from 2 months ago). * Furthermore, Fiasco.OC includes, from what I understand, a capability security model, which'd probably be handy for my purposes. However, I can find no documentation on this model. Are there any docs I'm missing? That actually holds for L4 in general as well as Fiasco, the only thing I could find is the X.2 API reference manual, and the very incomplete user manual. Are there any more complete versions of the user manual or other documents explaining the whys of L4, not just hows? * On the other hand, L4Ka has existing projects such as driver virtualisation, which are of great interest to me, as mentioned in the introduction. Thus I'd like to know how compatible in practice the different L4 implementations are. If I took the code from L4Ka's Afterburner, is it at all possible to run it on top of Fiasco, or would I have to rewrite it? Similarly, would it be possible to port NICTA's L4/Darwin IOKit compatibility layer to another L4, or is it tied to the specific implementation of L4 from NICTA? * Since I want to preserve the compatibility with existing environments such as POSIX and/or Win32, I'd like to know if anybody has done any practical research into running multiple OS personalities on top of a microkernel such as L4. I'd be extremely grateful for any links and/or advice regarding running personalities, as well as mixing code operating within the different subsystems. * Lastly, I'd like to know if there's any reasonably-populated IRC channel dedicated to L4. Since I'm still very much exploring the problem space more than the solution space, I appreciate the interactive nature of IRC, which helps me formulate questions I might not even know I have yet. I've found one old mail asking about IRC previously, with Adam's reply pointing to his personal homepage, but I still wasn't able to find any L4 channels that way. Cheers, Maciej Katafiasz

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