- Devel - lists.sel4.systems

Sporadic Server Implementation Details
by msudvarg＠wustl.edu 11 Feb '21

11 Feb '21

Hi all, I hope this is the right forum to be posting this question. I've reached out to Anna Lyons, the first author on the EuroSys 2018 "Scheduling Context Capabilities" paper (https://ts.data61.csiro.au/publications/csiro_full_text//Lyons_MAH_18.pdf) but I do not know if her listed email address is still active. I want to ask for more clarification on the sporadic server implementation in seL4. My interpretation of how the Lyons et al. paper describes the implementation is different than my understanding of the sporadic server definition as described by Sprunt et al. in 1989 (https://link.springer.com/article/10.1007/BF02341920) However, looking at the seL4 kernel source code, it seems that the actual implementation follows very closely with the improved POSIX sporadic server mechanism described by Stanovic et al. in 2010 (https://www.cs.fsu.edu/~awang/papers/rtas2010.pdf) In particular, the Lyons et al. paper states that when a thread is preempted at time t, a replenishment is scheduled for time t + T. My understanding of the sporadic server is that if a thread becomes active at time t, the replenishment is scheduled for time t + T. In other words, the replenishment is scheduled one period from when the thread begins execution, not when it ends execution. Further, a thread becomes active when it becomes unblocked (i.e. returns from a blocking system call, or is activated by the release of an aperiodic task that it handles). In other words, a thread that is preempted by a higher-priority thread is not considered to have become inactive, according to the sporadic server definition. This seems to be the case in both the Sprunt and Stanovic papers. I think the distinction is significant in a system (like seL4) where only a finite number of replenishments are tracked. Determining what number of replenishments each thread’s server must track is much easier if only voluntary yielding of the processor, and not preemption by higher-priority threads, triggers a replenishment. Can somebody explain to me in more detail how the sporadic server has been implemented in seL4? Like I said, from my reading of the kernel source, it seems that it has been implemented according to the improved POSIX sporadic server detailed by Stanovic, but I’m not certain that I’ve identified all conditions that cause a replenishment to be scheduled.

3 2

Use sel4 and mmc for storage but sdhc driver wait for SDHC_PRES_STATE_CIHB | SDHC_PRES_STATE_CDIHB
by MOHAMAD REZA SHAFIEI 10 Feb '21

10 Feb '21

hi there ... i'm working on mmc in sel4 for storage memory. i port your code for i.mx7 (modify registers and all need for that). so when i init mmc with calling mmc_init, sdhc driver wait at sdhc.c@249 and in this line: while (readl(host->base + PRES_STATE) & (SDHC_PRES_STATE_CIHB | SDHC_PRES_STATE_CDIHB)); indeed sdhc driver send function (sdhc_next_cmd(..)) send first command in mmc_reset (): which is : struct mmc_cmd cmd = {.data = NULL}; cmd.index = MMC_GO_IDLE_STATE; cmd.arg = 0; cmd.rsp_type = MMC_RSP_TYPE_NONE; printf("2-1\n"); host_send_command(card, &cmd, NULL, NULL); and status= 65 returned whicm means this command sent completely. so when program continue to send another command (still in mmc_reset) which is : /* TODO: review this command. */ struct mmc_cmd cmd2 = {.data = NULL}; ps_mdelay(10); cmd2.index = MMC_SEND_EXT_CSD; cmd2.arg = 0x1AA; cmd2.rsp_type = MMC_RSP_TYPE_R1; printf("2-2\n"); host_send_command(card, &cmd2, NULL, NULL); status which returned with sdhc send command in sdhc driver is 0. but this worked too. and when program execution continue to call mmc_voltage_validation(..) sdhc driver wait in while (readl(host->base + PRES_STATE) & (SDHC_PRES_STATE_CIHB | SDHC_PRES_STATE_CDIHB)); ... I don't have any idea why this happened .. can you help me? I didn't modify any code in sdhc.c or mmc.c ... my app for using mmc is here: #include <autoconf.h> #include <camkes.h> #include <camkes/io.h> #include <camkes/sync.h> #include <stdio.h> #include <utils/util.h> #include "string.h" //sdio test #include <sdhc/mmc.h> #include <sdhc/plat/sdio.h> #include <sdhc/sdio.h> #define max(x, y) (((x) >= (y)) ? (x) : (y)) //build config // #define TEST_FILESYSTEM 0 #ifdef CONFIG_64BIT #define BITS_PER_LONG 64 #else #define BITS_PER_LONG 32 #endif /* CONFIG_64BIT */ #define IMX7_GPIO1_BASE_ADDR ((uint32_t)NULL) #define IMX7_GPIO4_BASE_ADDR ((uint32_t)NULL) #define IMX7_SPI_BASE_ADDR ((uint32_t)NULL) #define IMX7_CTL_MUX_BASE_ADDR ((uint32_t)NULL) /** * we have two keyboard driver () */ bool STDKBD = true; #define IMX7_CTL_MUX_GPIO1_09 (0x18) seL4_CPtr timer_notification(void); seL4_CPtr notification; static void delay(uint64_t ms) { seL4_Word badge; /* test a relative timeout */ uint64_t t1 = timer_time(); // printf("Cur time: %"PRIu64"\n", t1); timer_oneshot_relative(0, ms * NS_IN_MS); seL4_Wait(notification, &badge); // printf("Badge: %x\n", badge); t1 = timer_time(); // printf("Cur time: %"PRIu64"\n", t1); } /* * Required for the camkes_sys_clock_gettime() in sys_clock.c of libsel4camkes. */ int clk_get_time(void) { uint64_t time_in_ms = timer_time() / NS_IN_MS; return (time_in_ms & 0xFFFFFFFF); } static int count = 0; ps_io_ops_t io_ops = {0}; struct netif* net_if; mmc_card_t mmc_card = 0; sdio_host_dev_t sdio_host_dev; int mmc_found = 0; void mmc_irq_handle(ps_irq_t* irq) { printf("mmc irq handle .... \n"); if(!mmc_found){ // printf("mmc not found yet :)\n"); // mmc_init handle this self // sdio_host_dev.handle_irq(&sdio_host_dev,irq->irq.number); mmc_irq_acknowledge(irq); return ; } // sdio_host.handle_irq(&sdio_host, irq); mmc_handle_irq(mmc_card,irq->irq.number); mmc_irq_acknowledge(irq); } int run(void) { notification = timer_notification(); int err = camkes_io_ops(&io_ops); if (err != 0) { ZF_LOGF("Can not init ops : %d\n", err); }; printf("initialize sdhc1 ...\n"); err = sdio_init(SDHC1, &io_ops, &sdio_host_dev); // while card not present check while(sdio_host_dev.reset(&sdio_host_dev) == -1){ delay(1000); } printf("before mmc_init\n"); mmc_init(&sdio_host_dev, &io_ops, &mmc_card); mmc_found = 1; printf("after mmc_init\n"); if (!err) { printf("SDHC1 inited successfully.\n"); // sdhc_ls(); } else { printf("SDHC1 initizatino failed!: %d", err); } // sdio_host_dev.reset(&sdio_host_dev); // mmc_init(&sdio_host_dev, &io_ops, mmc_card); // sdio_host_dev.handle_irq =mmc_handle_irq_func; while (true) { printf(".\n"); delay(1000); } return 0; } best regards.. shafie -- This email was Anti Virus checked by Security Gateway.

1 0

Public seL4 TSC meeting on Fri, 12 Feb
by Gerwin Klein 07 Feb '21

07 Feb '21

The Technical Steering Committee (TSC) of the seL4 Foundation will hold its next public meting on: Fri 12 Feb 2021 15:30-17:00 Sydney time (5:30am in Berlin, 8:30pm in San Francisco). This is the continuation of the meeting last week. The meeting is by Zoom, and you can register here: https://unsw.zoom.us/meeting/register/tZcqf--prz8jGNdE-zpwZXIBsbdYlN3fQn1Y Anyone interested can join the meeting and listen to the discussion and request to speak, which will be granted if time permits. Only TSC members can vote. The seL4 code of conduct applies to the meeting [1]. The agenda for the meeting so far is: Discussion points - when/how should Committer/Admin role change for people who have left D61 and had the role based on org membership - endorsement process for training and products Vote on: - Platform Owner proposal Discuss, potentially vote on RFC proposals: - https://sel4.atlassian.net/browse/RFC-6 - https://sel4.atlassian.net/browse/RFC-5 - https://sel4.atlassian.net/browse/RFC-4 If there are other items that I missed or you think should be on the agenda, please let me know. If we can't get to an item this time, we can still schedule another meeting. Cheers, Gerwin (TSC chair) [1]: https://docs.sel4.systems/processes/conduct.htmld

1 0

Public TSC meeting on Fri, 29 Jan
by Gerwin Klein 07 Feb '21

07 Feb '21

The Technical Steering Committee (TSC) of the seL4 Foundation will hold its next public meting on: Fri 29 Jan 2021 15:30-17:00 Sydney time (5:30am in Berlin, 8:30pm in San Francisco). The meeting is by Zoom, and you can register here: https://unsw.zoom.us/meeting/register/tZ0ocO6hrDwiGtTYlzULbKeTK8ybYJyCC7_p Anyone interested can join the meeting and listen to the discussion and request to speak, which will be granted if time permits. Only TSC members can vote. The seL4 code of conduct applies to the meeting [1]. Sorry about the very early time for Europe, but there are no time slots that work for the US, Australia, and Europe at the same time. We are planning to swap between better times for Europe and the US for the next meetings. The TSC is the body that decides on the technical direction of seL4: https://sel4.systems/Foundation/TSC/ The agenda for the meeting so far is: - updates from the TSC chair and committees: - seL4 public Jira - Jira + GitHub sync - reviewers who have joined - more GitHub tests - discussion points: - do we have too many different forums? - bug/issue classification (Jira is now public, we shouldn't call everything a bug) - more in-tree docs - test infrastructure - extend RFC process slightly? (see https://sel4.atlassian.net/browse/RFC-6?focusedCommentId=14886& ) - when/how should Committer/Admin role change for people who have left D61 and had the role based on org membership - endorsement process for training and products - vote on: - Platform Owner proposal - discuss, potentially vote on RFC proposals: - https://sel4.atlassian.net/browse/RFC-4 - https://sel4.atlassian.net/browse/RFC-5 - https://sel4.atlassian.net/browse/RFC-6 This is probably already too much for 90min and we may have to prioritise, but we will see how far we get. If there are other items that I missed or you think should be on the agenda, please let me know. If we can't get to an item this time, we can still schedule another meeting. Cheers, Gerwin (TSC chair) [1]: https://docs.sel4.systems/processes/conduct.html

2 5

Errors while running Virtual Machines on SeL4;
by Jorge Pereira 07 Feb '21

07 Feb '21

Hi all, I’m getting familiar with SeL4 build system and I’ve been running several application examples and also creating my own on top of the kernel using CAmKES. Very good. $ mkdir camkes-project; $ cd camkes-project; $ repo init -u https://github.com/seL4/camkes-manifest.git; $ repo sync; $ ../init-build.sh -DPLATFORM=sabre -DAARCH32=1 -DCAMKES_APP=helloworld -DSIMULATION=1 $ ninja $ ./simulate Again, so far, so good! Several CAmKES examples up and running. Now, I want to run virtual machines on top of it, I’ve seen several posts on internet and even in the official SeL4 website and none of them are working on my side. Can you please give me some pointers to be able to do so? We really want to start using SeL4 in our products with virtual machines, but current documentation is not ideal. I don’t have experience in CMAKE and that might be the real problem 😊. I need your help to ramp up in the SeL4 project! https://docs.sel4.systems/projects/camkes-arm-vm/ repo init -u https://github.com/seL4/camkes-vm-examples-manifest repo sync mkdir build cd build ../init-build.sh -DCAMKES_VM_APP=vm_minimal -DPLATFORM=tk1 When running ../init-build.sh I get the following: “ CMake Error at /home/jorge/hdd/work/projects/vm/Findcamkes-arm-vm.cmake:39 (find_package): By not providing "Findcamkes-vm-images.cmake" in CMAKE_MODULE_PATH this project has asked CMake to find a package configuration file provided by "camkes-vm-images", but CMake did not find one. Could not find a package configuration file provided by "camkes-vm-images" with any of the following names: camkes-vm-imagesConfig.cmake camkes-vm-images-config.cmake Add the installation prefix of "camkes-vm-images" to CMAKE_PREFIX_PATH or set "camkes-vm-images_DIR" to a directory containing one of the above files. If "camkes-vm-images" provides a separate development package or SDK, be sure it has been installed. Call Stack (most recent call first): CMakeLists.txt:19 (camkes_arm_vm_setup_arm_vm_environment) -- Configuring incomplete, errors occurred! See also "/home/jorge/hdd/work/build/CMakeFiles/CMakeOutput.log". “ Best, Jorge

1 0

seek for some help
by abdi mahmud haji 01 Feb '21

01 Feb '21

hi sorry for bothering you but i get some problem with sel4 tutorial when i trying to get starting with "repo init -u https://github.com/SEL4PROJ/sel4-tutorials-manifest" i got down bellow error and how can i fix it pls Traceback (most recent call last): File "/home/sel4/sel4-tutorials-manifest/.repo/repo/main.py", line 56, in <module> from subcmds.version import Version File "/home/sel4/sel4-tutorials-manifest/.repo/repo/subcmds/__init__.py", line s 38, in <module> ['%s' % name]) File "/home/sel4/sel4-tutorials-manifest/.repo/repo/subcmds/upload.py", line 27, in <module> from hooks import RepoHook File "/home/sel4/sel4-tutorials-manifest/.repo/repo/hooks.py", line 472 file=sys.stderr) ^ SyntaxError: invalid syntax tnks

3 2

Fwd: Regarding Ken Thompson's Reflecting on trusting trust...
by Bora Agca 30 Jan '21

30 Jan '21

Hi, i have one question: since the seL4 was written with a C compiler and it is possible that this compiler has an in-built backdoor, how can you still claim, that seL4 is "safe", i.e. non-hackable. Best regards and thanks in advance ___________________________ Bora Agca Diplom Informatiker Oracle Certified Programmer Java SE 6

2 1

Request for Speakers/Collaboration with WASI
by Zach Lym 29 Jan '21

29 Jan '21

I'm a community organizer for WASI <https://wasi.dev/>, a post-POSIX runtime with features that I think make it suitable for SeL4's planned post-POSIX runtime: * Fast and fine grained SFI via WASM. * Fast IPC and capability oriented security via WASM Reference Types <https://github.com/WebAssembly/reference-types/blob/master/proposals/refere…> . * High level interoperability across programming languages via WASI Interface Types <https://hacks.mozilla.org/2019/08/webassembly-interface-types/> and shared garbage collection <https://github.com/WebAssembly/gc/blob/master/proposals/gc/Overview.md>. * Wide range of targets: embedded, TEE, blockchain, browser, server, and (eventually) consumer operating systems. Industry cooperation is happening through the Bytecode Alliance <https://bytecodealliance.org/>, with partners like Red Hat ensuring commercial viability [1 <https://github.com/bytecodealliance/wasmtime/issues/70#issuecomment-4773292…> , 2 <https://github.com/bytecodealliance/wasmtime/issues/71#issuecomment-5180066…>]. Fastly is already using it for their serverless offering <https://www.youtube.com/watch?v=QdWaQOgvd-g>, which can scale to 20K processes/machine with a 35.4 microsecond cold start time. However, I believe the project would benefit *greatly* from the SeL4 community's experience architecting high-performance/high-assurance microkernels, IPC, and capability based security models. SOIL <https://soil-initiative.org/> is an academic effort to foster cross-pollination through biweekly seminars <https://soil-initiative.org/seminar/>. *We are seeking presenters from the SeL4 to better understand your needs and potential areas of collaboration*. Please contact Ross Tate (ross(a)cs.cornell.edu) if you are interested in presenting and jump on our Zulip Channel <https://bytecodealliance.zulipchat.com/> if you have any questions! Thank you, -Zach Lym

1 0

Accessing GPIOs on Raspberry Pi
by Zohra Charania 29 Jan '21

29 Jan '21

Hello All, I am new to seL4. I want to use seL4 in my project. As a starting point, I have compiled seL4 for Raspberry pi 3. As a next step, I have been trying to access GPIOs on Raspberry Pi. I used gpio.h from util_libs/libplatsupport/arch_include/arm/platsupport. I could not find any gpio.c for Rpi3/bcm2837 platform. When I compile the code, I am getting error: undefined reference to `gpio_sys_init'. Is there any support for GPIO access already available for Raspberry Pi? Could you please provide me guidance on how I can work with the Raspberry Pi GPIOs with seL4. Best Regards Zohra

1 0

Re: Cross VM Connectors
by PityTheFool 28 Jan '21

28 Jan '21

I discovered the answer by looking at the optiplex9020 example. Because the tutorial used the old modules, I had not fully integrated the new connector module into my project.

1 0