Devel April 2021

devel@sel4.systems

15 participants
13 discussions

Questions about Memory Management in seL4
by Daniel Wang 19 May '23

19 May '23

Hi all, Sorry to bother, I have some basic questions about seL4 memory management. Can someone help me? 1. where is the kernel’s address space? I know there are basically three methods: a) separate virtual address space, e.g. through changing page tables on entry into privileged mode to access b) physical space, e.g. through disable automatic hardware translation of virtual addresses on entry into privilege mode c) privilege region in each process’s virtual address space, e.g. through page table to map kernel address into use-mode process. My question is which of this is being used by seL4 microkernel? 2. Objects like CSpace, VSpace, CNode, TCB, Endpoint, etc. are called kernel objects, but it seems all dynamically allocated in thread running/creating time. Are those objects (e.g. Figure 3.3 in seL4 manual) in kernel space or in user space? 3. I read that after the kernel boot up, it passes all resources, untyped memory to the first thread. Are those untyped memory physical memory or virtual memory in a single page? The reason I ask is I’m learning the code of the UNSW AOS project (two of the assignment projects are implementing frame and papers). I’m confused that before the implementation of frames and pages what kind of memory is passed to the the first thread? I saw int AOS project, it uses ut_table_init(), ut_steal_mem(), I wonder what kind of memory it operates on? Thanks -Dan

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gic v2 vs gic v3
by Chris Koziarz 09 Jul '21

09 Jul '21

Hi all, I'm trying to port camkes-arm-vm to a different platform, that supports gic-v3 In the process, I hit a compilation error: Building C object kernel/CMakeFiles/kernel_all_pp_...rapper_temp_lib.dir/ kernel_all_pp_prune_wrapper_temp.c.obj FAILED: kernel/kernel_all_pp_prune_wrapper_temp.c In file included from /home/chris/camkes-tqma8xqp- vm/kernel/src/arch/arm/object/vcpu.c:15: /home/chris/camkes-tqma8xqp-vm/kernel/include/arch/arm/arch/machine/gic_v2.h:23: error: "IRQ_MASK" redefined [-Werror] 23 #define IRQ_MASK MASK(10u) In file included from kernel/gen_headers/plat/platform_gen.h:23, from /home/chris/camkes-tqma8xqp-vm/kernel/include/plat/ default/plat/machine.h:8, from /home/chris/camkes-tqma8xqp- vm/kernel/include/machine.h:9, from /home/chris/camkes-tqma8xqp- vm/kernel/include/api/syscall.h:10, from /home/chris/camkes-tqma8xqp- vm/kernel/src/api/faults.c:10: /home/chris/camkes-tqma8xqp-vm/kernel/include/arch/arm/arch/machine/gic_v3.h:30: note: this is the location of the previous definition 30 #define IRQ_MASK MASK(16u) which is an indicative that both gic_v3.h & gic_v2.h headers have been included, which is an error because said headers are not compatible: kernel/include/arch/arm/arch/machine/gic_v3.h:#define IRQ_MASK MASK(16u) kernel/include/arch/arm/arch/machine/gic_v2.h:#define IRQ_MASK MASK(10u) So my question is: how can I configure the build to avoid such a conflict? I can grepp the relevant configuration option in CMakeCache.txt: build_tqma8/CMakeCache.txt:CONFIGURE_INTERRUPT_CONTROLLER:INTERNAL=arch/machine/gic_v3.h but cannot see it in ccmake gui because it's "INTERNAL" What is the solution? - replace this option somehow to use gic_v2 and have my HW use gic v.2, or - change compilation options to use gic_v3 everywhere Thanks for any help, Chris.

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hello_rumprun app not worked
by MOHAMAD REZA SHAFIEI 13 Jun '21

13 Jun '21

hi. i'm recently worked on sel4 with camkes framework. when i compile rumprun_hello on x86_64 platform its compiled and build correctly but when run with qemu by ./simulate script, program crashed with this errors: simple_get_extended_bootinfo_length@simple.h:600 simple_get_extended_bootinfo_length not implemented FAULT HANDLER: data fault from hello.hello_0_control (ID 0x1) on address 0x8, pc = 0x402b7f, fsr = 0x6 FAULT HANDLER: Register dump: FAULT HANDLER: rip :0x402b7f , . . so i found that this method not implemented yet so i return 0 in this method and resolved. for second problem that cause failure if trace program and i found that in "init rumprun" process the program failed in the /projects/sel4runtime/include/sel4_arch/x86_64/sel4runtime/thread_arch.h file and sel4runtime_set_tls_base method. so i read git log and in recently commit your team use sel4runtime for thread TLS, so when we run rumprun_hello, the program failed in sel4runtime_set_tls_base method. can you help me fix this bug? thanks for your attention. -- This email was Anti Virus checked by Security Gateway.

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MMC wait after second command in intialization with mmc_init
by MOHAMAD REZA SHAFIEI 13 Jun '21

13 Jun '21

hi there . i'm work on mmc storage with sel4. i wrote a simple app that use mmc an here is that : ////////////////////////////////////////////////////////////////////// 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){ mmc_irq_acknowledge(irq); // printf("mmc not found yet :)\n"); sdio_host_dev.handle_irq(&sdio_host_dev,irq->irq.number); return ; } mmc_irq_acknowledge(irq); mmc_handle_irq(mmc_card,irq->irq.number); } 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"); } else { printf("SDHC1 initizatino failed!: %d", err); } while (true) { printf(".\n"); delay(1000); } return 0; //////////////////////////////////////////////// its work but in mmc_init after going to mmc_reset , first command sent but in second command (ie MMC_SEND_EXT_CSD ) wait for ever... can any body help me? best regards -- This email was Anti Virus checked by Security Gateway.

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Generating CAmkES glue-spec and glue-proofs
by Ben Fiedler 11 May '21

11 May '21

Hi everyone, I'm having troubles generating the CAmkES glue component specification and proofs from our source. I can and have successfully generated the ADL/CDL spec and implementations using the documented CMake parameters. Grepping around the docs I've found references to a 'camkes.sh' script, but neither the project tree nor the files generated during build contain it. One candidate reason could be that we set up our build environment strangely: We currently check out seL4/camkes-manifest and then symlink our component into the 'projects/global-components' subtree of the seL4. This works for generating bootable images, but I haven't found out how to generate the glue spec yet. Why we have set it up this way I don't know, and I suspect that there is a right way TM that we have overlooked/not found in the documentation. I appreciate any help in this regard. Thanks and have a nice day! Cheers, Ben

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Multiple ARM VMs with different CAmkES component configurations
by Olof Holmberg 11 May '21

11 May '21

Hi, I am currently performing research for my master thesis which involves seL4 and ideally retrofitting a SDN controller application for it. As a part of retrofitting applications for seL4 the suggested way is the incremental cyber retrofit approach wich involves dividing subsystems of the application onto several VMs that each runs in a VMM. Therefore I was wondering if it is currently possible to run several VMs on the ARM architecture that has different component configurations in CAmkES? (ARM is mostly preferable for the simple simulation in QEMU when building for qemu-arm-virt, so switching architecture is an option if this is not achievable) I noted that the macros for VMs on x86 and ARM were different when defining components: x86: /* VM and per VM componenents */ #define VM_PER_VM_COMPONENTS(num) \ component Init##num vm##num; \ /**/ ARM: #define VM_COMPONENT_DEF(num) \ component VM vm##num; \ And to clarify using the vm-examples where in the optiplex9020.camkes there are two VMs that are configured differently: component Init0 { dataport Buf(STRING_REVERSE_BUFSIZE) dp1; dataport Buf(STRING_REVERSE_BUFSIZE) dp2; emits Ready ready; consumes Done done; has mutex cross_vm_event_mutex; VM_INIT_DEF() } component Init1 { VM_INIT_DEF() } But in the ARM vm_multi.camkes there is only one VM component that is used for all three VMs: component VM { VM_INIT_DEF() maybe uses VirtQueueDev recv1; maybe uses VirtQueueDrv send1; maybe uses VirtQueueDev recv2; maybe uses VirtQueueDrv send2; attribute vswitch_mapping vswitch_layout[] = []; attribute string vswitch_mac_address = ""; } So it is at least it is not as simple as defining Init##num components for ARM since currently only one VM component is allowed in the macros. Do you have a recommended way that could achieve a CAmkES structure that allows for multiple differently configured VMs for ARM without altering the macros? If it is not possible at the time I assume that switching to x86 is the easiest alternative to achive this? Best regards, Olof

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Reducing memory footprint - RISC-V
by porter.188＠osu.edu 19 Apr '21

19 Apr '21

I'm trying to build a low memory footprint of RISC-V based seL4. I'm using QEMU/spike for now. In seL4 12.0 I can modify spike.dts to 8.5 MB of memory 0x00880000. 42 memory@80000000 { 43 device_type = "memory"; 44 reg = <0x00000000 0x80000000 0x00000000 0x00880000>; 45 }; This is the smallest value that builds, lower than this I get the error: [0/1] Re-running CMake... -- Found GCC with prefix riscv64-unknown-linux-gnu- STATUS,KernelDTSList: tools/dts/spike.dts -- /mnt/data/femur_12.0/build/kernel/gen_headers/plat/machine/devices_gen.h is out of date. Regenerating... STATUS,platform_yaml: /mnt/data/femur_12.0/build/kernel/gen_headers/plat/machine/platform_gen.yaml -- Detecting cached version of: musllibc -- Found valid cache entry for musllibc -- Configuring done -- Generating done -- Build files have been written to: /mnt/data/femur_12.0/build [18/36] Generating gen_headers/image_start_addr.h FAILED: elfloader-tool/gen_headers/image_start_addr.h cd /mnt/data/femur_12.0/build/elfloader-tool && sh -c "/mnt/data/femur_12.0/tools/elfloader-tool/../cmake-tool/helpers/shoehorn.py /mnt/data/femur_12.0/build/kernel/gen_headers/plat/machine/platform_gen.yaml /mnt/data/femur_12.0/build/elfloader-tool/archive.o > /mnt/data/femur_12.0/build/elfloader-tool/gen_headers//image_start_addr.h" shoehorn: fatal error: ELF-loader image "/mnt/data/femur_12.0/build/elfloader-tool/archive.o" of size 0x107548 does not fit within any memory region described in "{'devices': [{'end': 2147483648, 'start': 0}, {'end': 549755809792, 'start': 2155872256}], 'memory': [{'end': 2155872256, 'start': 2149580800}]}" ninja: build stopped: subcommand failed. What do I need to modify to get to < 2 MB? Thanks!

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seL4 Crowdsourcing Portal
by Gernot Heiser 15 Apr '21

15 Apr '21

Dear seL4 community, It is a pleasure to announce that seL4 now has a crowdsourcing portal, using the Linux Foundation’s LFX platform. Please help making seL4 stronger by donating, and encouraging others to do the same! https://crowdfunding.lfx.linuxfoundation.org/projects/e94c998c-bac2-4224-b0… Gernot

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Choosing correct hardware platform for CAmkES-arm-vmm Cross VM connector support
by Zohra Charania 15 Apr '21

15 Apr '21

Hi everyone, I am a PhD student. For my research, I want to use sel4 and developa system based on it. The idea is to use the arm based multi VM and cross VM communication ability of sel4 and provide a secure and isolated environment for the various applications running on the system. I was reading through the sel4 tutorials and documentation to find out which hardware would be suitable for this. I started learning sel4 with Raspberry Pi 3, but as Rpi3 does not have GICv2 or GICv3, I am not sure how do I develop the CAmkES-arm-vmm, multi VM and cross VM connector on it. As I wish to develop an application i.e a system architecture using sel4, itwould be good to have a device that provides me the starting point of having a multi VM and Cross VM communication. I read in the documentation that we can use Nvidia TK1-SOM from Colorado engineering to develop CAmkES-arm-vmm. But if I see the table here: _https://docs.sel4.systems/projects/camkes-arm-vm/_ , it says that CrossVM and Multi VM support is unsupported and in notes it says untested. According to the table, this is true for TK1, TX1 and TX2. Could someone please clarify what does this mean? Does it mean that we cannot have these features for these hardware or is it that they are not tested? It will be a great help to get this information, as then I can purchase the correct hardware and advance my work. I am new to micro-kernel community, so I apologize if I have missed anything obvious and would be glad to receive guidance and advice. Hoping for a kind response. Thank you. Sincerely, Zohra

1 0

[seL4 Announce] Operating System based on seL4.
by Gernot Heiser 12 Apr '21

12 Apr '21

<comment> The below message was posted to announce(a)sel4.systems. It was inappropriate for that list, but got though due to a configuration error (now fixed). I’m reposting it here as it would be appropriate for this list. Feel free to respond here. </comment> Hello, Which operating systems are based on seL4 Microkernel? Any home usage? Thanks.

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Devel April 2021