l4-hackers

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

2827 discussions

Server loop does not call dispatch only when running in pthread
by Tobias Sturm 24 Nov '14

24 Nov '14

Hi, I want to have the loop() method of a Registry_server instance inside a pthread. When the client sends messages, I get the IPC error 35 (could not figure out what that error code means). As soon as the loop() is invoked in my main thread, messages come through. Here is some pseudo code: start_thread() { //pack args int err = pthread_create(&my_thread, NULL, &thread_fn, &args); printf("pthread_create says %d", err); } thread_fn(args) { L4Re::Util::Registry_server<>* svr = args.server; server_obj* my_server = args.server_obj_instance; svr->registry()->register_obj(my_server, "foo"); svr->loop(); } class server_obj : public L4::Server_object { public: int dispatch( ... ); } server_obj::dispatch(...) { //never called } Thanks, Tobi

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Run and debug Fiasco.OC kernel and L4Re using a DSTREAM JTAG device and the ARM DS-5 IDE
by Mahdi Aichouch 21 Nov '14

21 Nov '14

Hello to everyone, I have a Freescale i.MX 6 ARM Cortex A9 Sabre SD board. I would like to test the Hello World example using the generated bootstrap.elf binary. I compiled the fiasco kernel and the l4re framework for the i.MX 6 ARM Cortex-A9 using the menu configuration in both cases. Instead of using an SD card to run the binary on the board, I would like to flash the RAM with the binary using the DSTREAM JTAG device and the ARM DS-5 IDE. I connected the board to my host using the mini-usb to serial cable, and I used minicom tool as a serial terminal. I tried to run the binary using the DS-5 debugger while the board is connected through JTAG, but I didn't see any debug message on the serial terminal. The source code I am using is from the "l4re-snapshot-2014092821". My questions: 1) Does anyone tried to run and debug fiasco kernel + l4re on a board using a JTAG device? What are the steps that I am missing? 2) The debug tool print a message saying that "WARNING(IMG53): bootstrap.elf has no source level debug information", what are the options required to include these information compiling the fiasco kernel + l4re? Thank you very much in advance. Best regards, Mehdi PS: screenshot of the IDE debugger view

4 10

SMP
by teclis High Elf 11 Nov '14

11 Nov '14

How does the fiasco L4Re do SMP? Are there commands for CPU affinity? How can I assign a specific process to a CPU? thanks,

2 1

Second UART and console
by teclis High Elf 10 Nov '14

10 Nov '14

Hi, I have a board with two UARTs on it and I need a second independent console connected to the other UART ( I have multiple virtual machines and I want to give each their own console). What would be the best approach for this? I see the UART drivers are linked into bootstrap. Does the same driver from bootstrap remain resident in memory and become part of the address space of con once its starts? Would I need to spawn a separate instance of con or could it be modified to support multiple consoles? thanks

2 1

memory layout
by Tobias Woelfel 08 Nov '14

08 Nov '14

Hello everybody, I am still working on the port for openrisc and have now some questions concerning the memory layout. (kern/xxx/mem_layout-xxx.cpp) What parts are necessary, and what do they mean? For example in the arm architecture there is Map_x, Caps_x, Kernel_x, Pmem_x... Are there any restrictions on how big/small one area has to be? What is the phys_to_pmem function supposed to do? (what does pmem stand for?) Thanks Tobias

2 1

How to monitor thread scheduling and the criticality of tasks?
by Karl Steger 05 Nov '14

05 Nov '14

Hi L4 hackers, How can you monitor how threads are scheduled for execution in L4Re? The trace buffer does not seem to offer information about the criticality of tasks. The l4re-snapshot-2014092821, however, refers to a monitoring framework named "ferret" in /obj/l4linux/ux/source/arch/l4/Kconfig but does not provide its source code. Is ferret publicly available? Do you know of any alternatives? Thanks and regards, Karl

2 1

Re: Question about schedule policy
by Björn Döbel 05 Nov '14

05 Nov '14

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, On 05.11.2014 04:18, Kevin wrote: > Thanks for your answer, please always reply to the mailing list. The answers may also be interesting to other people. > Maybe my question is confused. I know the concept of class > "Thread",It'sa runnable, schedulable activity, and a Task has many > Threads, and Task is just some address spaces. > > So, my question is: If there are many Tasks, for example, Task A > and Task B, and I want each Thread of Task A has a higher priority > than B's, what should I do? Fiasco schedules threads in a priority-based, round-robin fashion. That means it always selects the thread with the highest priority (per CPU). If multiple threads with the same prio exist, they get equal shares of the CPU. You can set a thread's priority upon creation using the l4_scheduler_*() system calls. There are examples of that in l4/pkg/examples - grepping for 'scheduler_' should do the trick. Furthermore, you can also set the prio of threads within the Lua init scripts. For that purpose you do something like: loader:startv({ caps = ..., log = ..., scheduler = L4.Env.user_factory:create(L4.Proto.Scheduler, 0x90, 0x80) }, ...); This sets up a scheduler environment for your new program. The numeric parameters are max_prio and base_prio. When you later specify priorities using the scheduler interface in your program, the actual prio of your threads will be calculated: prio := base_prio + selected_prio; if (prio > max_prio) prio := max_prio; > anyway, can we schedule these Threads by group? not just set the > scheduling parameters of Thread one by one. You need to set the scheduling parameters for every newly created thread separately. If you use the pthread interface, this will be done by the library and all threads will have the same prio. In combination with the Lua scheduler settings this might be what you want. Bjoern -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlRZ61EACgkQP5ijxgQLUNn58ACfXN2gmSGxUMD602bB2h26mIbq VssAniec6EQs4q1VTo/0zVBj1mgQgm0Q =oY4R -----END PGP SIGNATURE-----

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Question about schedule policy
by Kevin 04 Nov '14

04 Nov '14

Hello, I know the class "Task" in fiasco is equaled with the word "Domain" in VMM, but I can't find some schedule policy about Task in fiasco, all I find is scheduling about Thread in class Context and sched_context. So, is there any schedule policy about Task? thanks, kevin

3 2

is there a way to run the compiled arm on Nexus S ?
by cem akpolat 04 Nov '14

04 Nov '14

Dear all, I have compiled couple of days ago l4android for arm architecture, and now I want to boot it on Nexus S, however, I couldn't find a way to tun bootstrapLinuxAndroid.elf file on arm based architecture. I have already seen in some research papers (one of them is as follows). http://www.isti.tu-berlin.de/fileadmin/fg214/liebergeld/spsm03-lange.pdf How could be l4android booted on the Nexus S? Thanks, Best Regards, Cem Akpolat

4 9

FOSDEM 2015 - CfP: Microkernels DevRoom
by Vasily A. Sartakov 01 Nov '14

01 Nov '14

Greetings. ---- FOSDEM 2015 - CfP: Microkernels DevRoom I would love to announce the Call for Participation in the FOSDEM'15 Microkernel DevRoom. FOSDEM’15 will be held at the ULB Campus Solbosch on Saturday 31 January and Sunday 1 February 2015 and Microkernel devroom is scheduled on Sunday (01 February). Topics accepted include, but are not limited to: * Kernels, environments and frameworks * Hardware support: architectures, drivers * Languages and tools * Use cases, experiences, lessons learned and demos * Technical challenges and issues * Testing and support * Community building. Please use Pentabarf [1] system to submit your proposals. You do not need to create new account if you already have one. If the password is lost you can recovery it. Moreover, we have the devroom mailing list [2] Within submission please provide: * Title of your talk * Abstract, one or two paragraphs * Information about speaker: Name, bio, photo * Length of the talk. Each talk is limited to 45 minutes but can be less. Important dates: * Nov 28: Deadline for submissions * Dec 01: Speakers notified of acceptance * Dec 08: Schedule published Please do not hesitate to forward this CfP to anyone interested in participating. 1. https://penta.fosdem.org/submission/FOSDEM15 2. https://lists.fosdem.org/listinfo/microkernel-devroom ---- -- Vasily A. Sartakov sartakov(a)ksyslabs.org

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