l4-hackers December 2015

l4-hackers@os.inf.tu-dresden.de

9 participants
10 discussions

Graphical desktop, l4con, mag
by teclis High Elf 02 Jun '17

02 Jun '17

Guten Tag, I've got the Hello app runing with fiasco and l4re in qemu, how do I get the graphical UI and console running that I see on the screen shots page? Do I need to use l4con and mag? I don't see an entry with l4con in modules.list. danke * <http://german.about.com/library/media/Audio/gutentag.wav>*

6 15

libfs/ FUSE on L4Re
by Stark, Josef 31 May '17

31 May '17

Hello, yesterday I came across a very interesting paper titled "Porting FUSE to L4Re", accessible here: http://os.inf.tu-dresden.de/papers_ps/pester-beleg.pdf For porting FUSE, the author uses a library called "libfs" which provides filesystem request forwarding and processing, if I understood correctly. It reads as if libfs is already included in L4Re. However, I couldn't find neither FUSE nor libfs in the current L4Re snapshot. Are they by any chance publicly available somewhere else, or are both not to be published? Cheers, Josef

4 7

Hiring engineers for seL4 work
by Gernot Heiser 12 Jan '16

12 Jan '16

Do you want to be paid for contributing to the seL4 microkernel and its ecosystem, and getting your code used in critical systems on a large scale? As part of a kick-ass team, while living in Sydney, one of the world’s most liveable cities? The seL4 team at DATA61 (formerly NICTA) is hiring OS engineers, see https://ssrg.nicta.com.au/jobs/OS-engineers2015 We’re also hiring: - proof engineers: https://ssrg.nicta.com.au/jobs/proof-engineers2015 - researchers/postdocs: https://ssrg.nicta.com.au/jobs/OS-researchers2015 Gernot

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Question about memory management in L4 Fiasco O.C + L4re
by Mahdi Aichouch 04 Jan '16

04 Jan '16

Hello, I have some questions concerning memory management in Fiasco O.C + L4re. I would like to test two L4Linux instances, and for each L4Linux instance I want to reserve one static fixed physical memory partition. For instance, one 128MB for the first L4Linux and one 128MB for the second. Knowing that Fiasco O.C. uses "on demand paging" to allocate pages for user tasks, is it possible that each partition of L4Linux could be allocated a static physical memory region composed of contiguous physical frames. For instance, one memory region starting from 128MB to 256MB for the first L4Linux, and second memory region from 256MB to 512MB for the second L4Linux. Each memory region is allocated exclusively to one L4Linux instance. I would like to know if it is possible to load all the code + data of a L4Linux instance into its reserved memory partition, so no page fault will be encountered during runtime. Is it possible to tell me if these above operations could be realized in Fiasco O.C and L4re? If the answer is yes, is it possible to tell me what are the objects that should be used or adapted in order to implement these? What are the issues that I should pay attention to? Many thanks in advance for your answer. Best regards, Mahdi

2 37

L4Re Update
by Adam Lackorzynski 04 Jan '16

04 Jan '16

Hi, After a longer break I'm pleased to announce an update of the L4Re system software. https://l4re.org Besides bug fixes and enhancements, noteworthy changes and additions of this update include: All: - LLVM/Clang: Fiasco.OC is supported with Clang now, for the userland we're nearly there - Updates for recent GCC versions - CROSS_COMPILE is the preferred way to set the compiler prefix now - URLs have been consolidated to be under the l4re.org domain but old ones will remain to work for a foreseeable future. L4Re: - Package reorganization: Core packages have been moved to a more hierarchical structure, e.g. l4re-core and io - New RPC framework using C++ that generates client and server side code from a single definition, code and examples have been adapted accordingly - Software updates, e.g. libstdc++, lua, libpng, libjpeg, lwip - New L4Re::Dma_space interface to support DMA and IOMMUs - io gained support for IOMMUs and MSI remapping - Virtio library to support the development of virtio host applications - Documentation improvements: https://l4re.org/doc/ Fiasco.OC: - IOMMU support, including MSI remapping (currently VT-d) - Clang support L4Linux: - Added x86-64 variant - Updated to version Linux 4.3 - MSI / MSI-X support Happy new year, Adam

4 3

Performance of L4
by Patrick Staeblein 28 Dec '15

28 Dec '15

Hello Dear L4 Hackers, I am still writing on my bachelors-thesis on the performance of L4/Fiasco and wanted to ask you if you can give me some hints and ideas. My goal was to find out how the time-costs are divided between ipc, memory access and scheduling and resulting out of this what properties programs should have that makes them execute as fast as possible. For measuring the ipc-time i used the ipc_example.c-file in the ./src/l4/pkg/examples/sys directory and added rdtsc (Read Time Stamp Counter)-instructions before and after making the ipc-call and then calculating the difference between the two values. This was executed in a loop and the resulting values were divided into ten equal-sized range-classes depicting them as a histogram.The results showed the ipc-time to be pretty stable with almost all values falling into one class (Sorry for my shitty Englisch anyway). Does anyone have an idea what kind of measurement one could do for a measurement of the scheduling? I found the function l4_scheduler_idle_time (...), but I don't have an idea for using it in a concrete program or experiment setup. I also thought about repeatedly measuring the time it takes for one context-switch, but I don't know in which place exactly I would have to insert the rdtsc-instructions. Does anyone know which exact C-file would have to be modified for that? I am thankful for any answer, regards, the Steppenwolf

2 1

Serial console not working
by Lluís Vilanova 22 Dec '15

22 Dec '15

Hi there! I'm trying to find out why my setup is not booting on a real machine (some Dell PowerEdge R210 node; ned says it cannot find rom/l4re), but I'm unable to redirect output to the serial console. I'm able to use the serial console for both grub and linux, so it's not a hardware issue. An excerpt of my grub2 configuration: serial --unit=1 --speed=115200 --word=8 --parity=no --stop=1 terminal_input serial terminal_output serial # ... # for the linux entry linux /vmlinuz-3.16.0-4-amd64 root=UUID=7573ed62-a910-4b97-a577-dde47a16f87a ro console=ttyS1,115200n8 quiet Now, here's the entry I'm using for L4, which never gets me any output on the serial console: menuentry 'Test' { set root=(hd0,1) multiboot /l4/bootstrap -serial module /l4/fiasco -serial_esc -comspeed 115200 -comport 1 module /l4/sigma0 module /l4/moe rom/test.cfg module /l4/l4re module /l4/ned module /l4/test.cfg module /l4/bin/test } Thanks, Lluis

2 3

Problem with Hello app on Zedboard
by Manolis Ragkousis 14 Dec '15

14 Dec '15

Hello everyone, I am trying to make the Hello app run on the zedboard but it gets stuck at "Scanning up to 512 MB RAM, starting at offset 32MB". I have configured both fiasco and l4re with the correct configuration (I have attached my config files) and cross compiled them from a x86_64 linux machine with "Linaro GCC 4.9-2014.09 4.9.2 20140904". I searched the mailing lists archives but I can't seem to find a similar problem. I tried changing the uart port I was using, in case it was printing in another port, but nothing changed. Any ideas/suggestions on what could go be going wrong and/or how can I solve it? Thank you for your time, Manolis The output of u-boot: reading uImage 970816 bytes read in 108 ms (8.6 MiB/s) reading initramfs.cpio.gz 128 bytes read in 17 ms (6.8 KiB/s) reading devicetree.dtb 9331 bytes read in 16 ms (569.3 KiB/s) ## Booting kernel from Legacy Image at 03000000 ... Image Name: L4 Image #2 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 970752 Bytes = 948 KiB Load Address: 01000000 Entry Point: 01000000 Verifying Checksum ... OK ## Loading init Ramdisk from Legacy Image at 02000000 ... Image Name: Image Type: ARM Linux RAMDisk Image (gzip compressed) Data Size: 64 Bytes = 64 Bytes Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK ## Flattened Device Tree blob at 02a00000 Booting using the fdt blob at 0x2a00000 Loading Kernel Image ... OK Loading Ramdisk to 0f31d000, end 0f31d040 ... OK Loading Device T^H.��.\\Build: #2 Fri Dec 11 14:35:25 EET 2015, 4.9.2 20140904 (prerelease) Scanning up to 512 MB RAM, starting at offset 32MB

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real time app on l4linux
by cem akpolat 14 Dec '15

14 Dec '15

Hi, I want to ask, if you have any guide or documentation, how to write a real time app on l4linux. As you know, l4llinux doesn't guarantee whether the application .which run on top of it, will be close to real time or not. In this case, should we write an separate l4 app and communicate with l4linux over IPC? If yes, again, how can I implement this kind of an app. For instance, if we take the server-client app under examples folder, can we apply the same scenario? How can I communicate with L4Linux? Sincerely, Cem Akpolat

2 3

Reminder: Microkernel-devroom CfP deadline is on this Sunday
by Jakub Jermar 07 Dec '15

07 Dec '15

Hi folks, the CfP deadline for the Microkernel devroom at FOSDEM 2016 is due this Sunday. See the original CfP [1] for information on what to do if you would like to give a talk about some microkernel-related topic. At the same time, I would like to encourage you to submit a talk proposal. It would be shame not to let the wider microkernel community know about the latest and greatest developments in your project. Lastly, please forward this reminder to whoever you think may want to give a talk in the devroom and is not among the recipients of this message. Thanks, Jakub [1] http://trac.helenos.org/wiki/Devroom2016

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l4-hackers December 2015