December 2022 - Devel - lists.sel4.systems

hello_rumprun app not worked
by MOHAMAD REZA SHAFIEI 19 Apr '25

19 Apr '25

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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seL4 test on x86
by Yevgeny Lavrov 30 Jan '25

30 Jan '25

Hello, I'm new to seL4 and I'm just doing it for learning purpose. I'm trying to run seL4 test suite or simple hello world task from seL4 tutorials on the real hardware. So far I had no problems compiling seL4 test suite and running via QEMU for both x32 and x64 platforms. However, when I try to run it on the actual hardware following Running on real hardware tutorial for x86 I end up with no output at all and no error msgs that can give me a clue on where something went wrong. After compiling seL4test for x86, I ended up with two images in sel4_dir/images/ folder. Copied them over to /boot/sel4/ folder and created a new GRUB2 entry that looks like this menuentry “seL4 test suite” --class os { load video insmod gzio insmod part_msdos insmod ext2 set root=’(hd0,msdos5)’ multiboot /boot/sel4/kernel-ia32-pc99 module /boot/sel4/sel4test-driver-image-ia32-pc99 } update grub, restart and select the new entry from GRUB menu. I end up with blinking cursor on the top-left side of the screen. Please advise.

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Stuck during invalidate local TLB in Tx2
by Muneeswaran Rajendran 16 Oct '24

16 Oct '24

Hi seL4 Dev team, Can someone explain the reason (share the reference) to invalidate the local TLB during kernel vspace activation as part CPU initialisation. The Tx2 board stuck while performing this operation. As per my understanding both Tx1 and Tx2 are using same A57 core. so the TLB initialisation and invalidation remain same for Tx2 and should not stuck during invalidation.Please correct me if anything wrong here. I understand from that instruction (tlbi vmalle1) which is invalidating stage 1 entries associated to the current VMID. Also from arm mmu code the seL4 setting up (TCR_EL1) TCR register addressing space as 48bit, ASID as 16bit and page table setup 4k granular size. I am using MRS macro to dump the spsr_el1 and dspsr_el0 register to see the state of processor but its throwing synchronous exception. Do we have any other option to dump all the register content to see the state of processor like we have one in 'sel4debug_dump_registers' which is used in sel4test code. Regards, Muneeswaran R

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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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Question about non-blocking notification
by mincheol＠vt.edu 31 Dec '22

31 Dec '22

Hi, Do I need to use seL4-NBSend() for sending a non-blocking signal (cause seL4_Signal() is blocking)?

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Question about sel4-tutorial dynamic-2 and dynamic-3
by mincheol＠vt.edu 29 Dec '22

29 Dec '22

Hi, I have two questions regarding dynamic-2 and dynamic-3 tutorials. 1. In dynamic-2 TASK 4, Why is the ipc_buffer_vaddr put in seL4_ARCH_PageTable_Map()? ipc_buffer_vaddr is the virtual address of the new physical frame allocated for the IPC buffer. I think seL4_ARCH_PageTable_Map's 3rd parameter is the virtual address of the page table frame. 2. In dynamic-3, it uses sel4utils_configure_process_custom() to create a new thread. I looked into the function and found that it created a vspace for the new thread. However, the tutorial's learning outcomes section says "this time the two threads will only share the same vspace", so I am confused. Does this tutorial create a new vspace for the new thread? Mincheol

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Any reliable way to determine if a thread is suspended?
by Andrew Warkentin 28 Dec '22

28 Dec '22

Is there any reliable way to determine if a thread is suspended? seL4_TCB_Suspend() succeeds even if the thread was already suspended. I can force all calls to seL4_TCB_Suspend() and seL4_TCB_Resume() to go through a wrapper that updates a user-level flag (since my OS manages pretty much all capabilities in the root server and will only expose TCBs to regular user processes through a special filesystem); however, this leaves a race when a thread is suspended due to a fault instead of an API call (since the thread will already be suspended before the fault handler updates the "thread running" flag). My initial use for checking if a thread is running is to allow easy atomic updates of some metadata (shared between the root server and the non-root thread, and optionally shared between threads) for my IPC transport layer that implements Unix-like file descriptors on top of seL4 endpoints (and eventually notifications). To add an FD to a thread's list, the root server allocates a copy of the endpoint (and reply if the FD is server-side) into the thread's CSpace, suspends the thread, updates the metadata (which includes the underlying capabilities), and then resumes the thread if it was running. Obviously, I don't want to resume threads that weren't running in the first place. I don't want to use locks here since the root server can't trust regular user processes. Another use is to allow cancelling any in-progress transfers on FDs when they get closed and returning a status to the waiting threads, which I am planning to do by replacing the endpoint with a copy of a global "clunk endpoint" associated with a thread that repeatedly sends a "file descriptor closed" message (actually there will be two such threads - one for clients, and one for servers) and then resuming the thread.

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problem Ethdriver 82574 on Qemu X86_64
by reza yazdanparast 25 Dec '22

25 Dec '22

Hi. I'm working on a new camkes-based project. This project is simulated by using Qemu, on a Q35 machine for X86_64 arch and e1000e eth. I am using an intel controller driver (82574 controller) for network communication. My project has been built successfully and the intel network driver has been initialized. But when using the network in my application in Qemu, no network packet is sent and received! Qemu command: ``` sudo qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split -cpu host, -netdev tap,id=netdev0,ifname=tap0,script=no,downscript=no -device e1000e,id=nic0,netdev=netdev0,mac=52:55:00:d1:55:01 -nographic -serial mon:stdio -m size=4G -device intel-iommu -kernel ./target/debug/images/kernel-x86_64-pc99 -initrd ./target/debug/images/capdl-loader-image-x86_64-pc99 ``` . Appendix: Create tap0 command: ``` export TAP_DEV=tap0 sudo ip tuntap add dev $TAP_DEV mode tap sudo ip addr flush dev $TAP_DEV sudo ip addr add 10.10.100.1/24 brd 10.10.100.255 dev $TAP_DEV sudo ip link set dev $TAP_DEV addr 02:00:ca:fe:01 sudo ip link set dev $TAP_DEV up ``` . how to fix this problem? Thank you.

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any fun holiday hacks with sel4?
by ember arlynx 25 Dec '22

25 Dec '22

merry christmas :) i've been thinking about reviving some rusty robigalia-ish things. how are you all doing, this stormy sunday? -- ember

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next seL4 TSC meeting on Fri 16 Dec (15 Dec in US and Europe)
by Gerwin Klein 16 Dec '22

16 Dec '22

The Technical Steering Committee (TSC) of the seL4 Foundation will hold its next public meting on: - Sydney: Fri, 16 Dec, 8am - Central Europe: Tue, 15 Dec, 10pm - US West Coast: Tue, 15 Dec, 1pm See also the seL4 calendar feed available from here: https://sel4.systems/contact/home.pml The meeting is by Zoom, and you can join from here: https://unsw.zoom.us/j/5510249963 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: - election (or re-election) of TSC chair - split C-Parser/AutoCorres out from l4v repository - RFCs: - SMC https://sel4.atlassian.net/browse/RFC-9 - MCS: Improve constraints on grant via reply https://sel4.atlassian.net/browse/RFC-13 - MCS: set fault and timeout handler parameters while configuring TCBs https://sel4.atlassian.net/browse/RFC-11 - The seL4 Core Platform https://sel4.atlassian.net/browse/RFC-5 - The seL4 Device Driver Framework https://sel4.atlassian.net/browse/RFC-12 - Ability to build additional bootloaders inside the seL4 build system https://sel4.atlassian.net/browse/RFC-4 - SIG chair nominations - discuss process for establishing SIGs 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

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