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Some questions about seL4 operating system
by Qing Wei 22 Aug '15

22 Aug '15

Hi, I am a beginner to seL4 as well as microkernel, and very interested in it. I think it is great in terms of its minimality and formally verified security. However, I have some questions about it, (1) How is its performance compared to other monolithic kernel, say, Linux. Could it make use of multicore, multiprocessor to enjoy the performance scalability? (2) How is its ecosystem, fox example, how to support new hardware, does it need write the driver from scratch or could it make use of Linux driver? And how to write application on it, or, could it run Linux application without modification? (3) How is its virtualization support, could it run Linux vm, and does it need any modification to the guest os? Cheers, Qing Wei

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Some comments.
by Mehdi Amiri 17 Aug '15

17 Aug '15

Hi, Thank you for all your efforts and time. I believe the user community is the main success key for all open source projects. Many users and researchers, do not have enough time to read, download and evaluate all the source code in order to investigate a system to see if it is suitable for their research or usage. Usually they will go for clean systems which are easy to use, simple to understand, well documented and have a strong community beside the commercial support to ask and get help in case they had a problem. Here are some comments which may help to increase the number of users and developers for seL4: A) I suggest to add some howtos to the website. It's better to be a wiki like system so other individuals, researchers and students can help in writing some titles. Some interesting topics (at least for me as a beginner in micro-kernel) could be: 1- Running Linux/Android on top of seL4. 2- Writing a simple user application with a use case (not just the SOC). 3. Examples on real-time application. 4- Writing a service (could be a device driver, file-system, etc) for seL4. 5- Documents on using possible run-times like Genode. 6- Documents or case studies on porting an opensource software from Linux or POSIX based system to directly run om seL4. B) Providing ready to use download binary images for supported platforms can also accelerate growth of community. C) A research areas page which can suggest researchers some ideas to chose a title and do their research to expand seL4 could also be useful. Ideas like rump-kernels, lib-OS, visualization (x86/ARM), etc seems to be possible research titles on seL4. I have seen the https://sel4.systems/GettingStarted/ page and I think other than CAmkES, ports and Qubes there could be many more titles. D) I know the major development platform of seL4 has been the Arm architecture, but optimizing the code to utilize the x86 architecture including virtualization can also bring a lot of attention to this project to use seL4 as a replacement for Linux-KVM and Xen in the cloud, IoT or real time systems when stability and security is a matter. Also please note, the archive of both development ( https://sel4.systems/pipermail/devel/) and announcements ( https://sel4.systems/pipermail/announce/) mailing lists are not accessible trough the website. I'm an OS researcher and a senior system engineer (mostly Linux) with a limited time, but I can help in some parts if you think it may be useful. Thank you again! Best Regards, Mehdi

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other communications
by Raymond Jennings 17 Aug '15

17 Aug '15

Is there a mailinglist or forum anywhere for people interested in using seL4? I realized this is a dev list and may not be the right place to ask technical supportr questions.

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Detecting dirty/accessed page tables
by Raymond Jennings 15 Aug '15

15 Aug '15

Hey I'm just curious...how do you detect if a memory page mapped by a page table has been written to or accessed? I imagine if you're writing a filesystem task, such information would help you know when to flush data back to disk or which pages to keep around if things get tight. I hope this isn't a stupid question.

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U-boot help sabrelite
by Andrew Shruhan 12 Aug '15

12 Aug '15

Hi, I am attempting to follow the tutorial booting from SPI for the sabrelite https://sel4.systems/Hardware/sabreLite/ when booting I obtain this output and am not able to run "run bootsel4_mmc" U-Boot 2009.08-dirty (Jun 27 2013 - 16:26:46) CPU: Freescale i.MX6 family TO1.2 at 792 MHz Temperature: 36 C, calibration data 0x56a4bc7d mx6q pll1: 792MHz mx6q pll2: 528MHz mx6q pll3: 480MHz mx6q pll8: 50MHz ipg clock : 66000000Hz ipg per clock : 66000000Hz uart clock : 80000000Hz cspi clock : 60000000Hz ahb clock : 132000000Hz axi clock : 264000000Hz emi_slow clock: 132000000Hz ddr clock : 528000000Hz usdhc1 clock : 198000000Hz usdhc2 clock : 198000000Hz usdhc3 clock : 198000000Hz usdhc4 clock : 198000000Hz nfc clock : 24000000Hz Board: MX6Q-SABRELITE:[ POR] Boot Device: I2C I2C: ready DRAM: 1 GB MMC: FSL_USDHC: 0,FSL_USDHC: 1 JEDEC ID: 0xbf:0x25:0x41 Reading SPI NOR flash 0xc0000 [0x2000 bytes] -> ram 0x276009b8 SUCCESS In: serial Out: serial Err: serial Net: got MAC address from IIM: 00:19:b8:01:fd:6d FEC0 Hit any key to stop autoboot: 0 AHCI 0000.0000 1 slots 1 ports ? Gbps 0x0 impl SATA mode flags: No port device detected! Unknown command 'load' - try 'help' SATA device 1: unknown device Unknown command 'load' - try 'help' Card did not respond to voltage select! mmc0(part 0) is current device Unknown command 'load' - try 'help' mmc1 is current device Unknown command 'load' - try 'help' Unknown command 'usb' - try 'help' Unknown command 'usb' - try 'help' Unknown command 'load' - try 'help' Unknown command 'usb' - try 'help' Unknown command 'load' - try 'help' 6x_bootscript not found serial console at 115200, 8N1 details at http://boundarydevices.com/6q_bootscript AHCI 0000.0000 1 slots 1 ports ? Gbps 0x0 impl SATA mode flags: No port device detected! AHCI 0000.0000 1 slots 1 ports ? Gbps 0x0 impl SATA mode flags: No port device detected! Card did not respond to voltage select! mmc0(part 0) is current device expose mmc drive 0 over USB Unknown command 'ums' - try 'help' Card did not respond to voltage select! no block devices found ERTOS MX6Q SABRELITE U-Boot > -- -Andrew Andrew P. Shruhan Research and Development Engineer III DocBox, Inc. 320 Nevada St Newton MA, 02460 Work: 857-598-2819 ext. 117 www.docboxinc.com

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Upstream seL4/RISC-V work?
by Hesham ALMatary 10 Aug '15

10 Aug '15

Hi, The seL4/RISC-V port is now working on Spike (emulator), Rocket Chip (FPGA), and jor1k (online emulator). I've also written a recent blog post how to build/run the port with SOS project [1] from my repos). The code is pretty much like the ARM port, and following the same bootstrapping procedure (more on this on my blog). MMU code provides 4KiB and 4MiB pages (like IA-32). I'd like to ask if there are special requirements to upstream this work: * All libraries that are target-dependant. * seL4 microkernel. * Tools (elf loader, build system). * SOS project? I understand it won't be an easy process because this work is the first "foreign" code that big, of course apart from formal verification. But it wouldn't hurt to ask. [1] http://heshamelmatary.blogspot.co.uk/2015/07/howto-build-and-run-sel4-on-ri… Best, -- Hesham

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Porting Linux driver into Sel4
by Shabnam Engineer 09 Aug '15

09 Aug '15

HiI have a question about porting Linux drivers in Sel4.Can I port Linux drivers into Sel4? I know that DDEKit provides such functionality for L4-based systems and I could find the implementation of that in fiasco.OC microkernel, but I can not find same works for Sel4. I want to implement Sel4 on a board and test some features, At first I want to be sure that if I need a driver for our special tests and the Sel4 does not support that, Could I choose it from Linux drivers and port it to Sel4 microkernel? Thank you for your considering my question.Regards,Shabnam

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Wandboard Port
by Robert Kaiser 30 Jul '15

30 Jul '15

Hello, in an attempt to familiarize myself with the seL4 code, I am trying to "port" it to the Wandboard (see www.wandboard.org) This should be an easy task for a beginner (thought I) since the board is very similar to the SabeLite, and seL4 is already running well on that board. I have access to a SabreLite and a Wandboard Quad, both (according to U-boot) have the same revision of the iMX6 SoC installed. Differences between the Sabre and the Wand I have noticed so far are: - 2GB of RAM from (0x10000000 to 0x90000000) on the Wand (Sabrelite has 1GB) - Wand uses UART1 for debug output, Sabrelite: UART2 I compiled an sel4test project where I adapted the UART port in kernel/include/plat/imx6/plat/machine/devices.h and elfloader/src/arch-arm/plat-imx6/platform.h and the RAM size in kernel src/plat/imx6/machine/hardware.c. When I boot this system, I get: Jumping to kernel-image entry point... Bootstrapping kernel Caught cap fault in send phase at address 0x0 while trying to handle: vm fault on data at address 0x9f11c2e0 with status 0x1c06 in thread 0xffdfad00 at address 0x13294 (Needless to say, "all is well in the universe" on the SabreLite... ) What is not shown here are a ton of other debug messages which I have added to convince myself that kernel initialization completes as expected. The crash seems to happen upon entry into user code. The address 0x13294 is the virtual address of the entry point: $ nm build/arm/imx6/sel4test-driver/sel4test-driver.bin | grep 13294 00013294 T _sel4_start I suspect that this fault happens on opcode fetch, because the user code is not properly mapped when invoked. Does "status 0x1c06" confirm this? If so, *should* the code be mapped at this point or are these mappings expected to be installed "on demand", i.e. through page fault handling? Thanks for any help... Robert -- Robert Kaiser Computer Engineering RheinMain University of Applied Sciences

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Happy Birthday, Developers!
by Gernot Heiser 29 Jul '15

29 Jul '15

Hi everyone, Today is the anniversary of the open-sourcing of seL4. At NICTA we’re celebrating, I hope you’ll virtually join us ;-) Let me add that I quite enjoy this mailing list. Traffic has a high signal-noise ratio (apologies for degrading it with this message ;-) people generally seem to know what they are doing, and the community is clearly growing. Presently there are over 300 addresses on the list. Many thanks from all of us at NICTA, and keep it up! Gernot [cid:1374281D-B193-431C-AA3F-D6EE049C461A@keg.ertos.in.nicta.com.au] ________________________________ The information in this e-mail may be confidential and subject to legal professional privilege and/or copyright. National ICT Australia Limited accepts no liability for any damage caused by this email or its attachments.

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CMake and seL4
by Wink Saville 29 Jul '15

29 Jul '15

In my opinion the edit/compile/test loop with the standard build system seeed slow, so I thought I'd try to see if CMake might be any better. Here <https://github.com/winksaville/sel4-newlibs-manifest> is repo manifest which uses CMake for building my sel4-newlibs helloworld application and I'm happy to report there is some improvement. For a "clean" build it is about 2x faster, 8 seconds as compared to 14 seconds. And for a small change to apps/helloworld/src/main.c it is 20x faster, 0.3 seconds as compared to 7 seconds. Is there any interest in using CMake or other build system to reduce the builds times for seL4? -- Wink

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