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seL4 hangs during invalidate local TLB
by Vishal Gupta 16 Oct '24

16 Oct '24

Dear seL4 developers, I am a seL4 enthusiast. I am trying to port seL4 on arm64 cortex a53. I am able to port elf-loader successfully and move to the kernel initialisation which reaches till “try_init_kernel->init_cpu->activate_global_pd->invalidateLocalTLB->asm volatile()”. Under InvalidatelocalTLB with asm volatile(“tlbi vmalle1”); in this , the system gets hanged and the asm function does not move forward. Any input or guidance would be really appreciated. Thank you . Regards, Vishal

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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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seL4 developer hangout reminder
by Birgit Brecknell 30 Sep '24

30 Sep '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Tue 1 Oct, 10:00pm UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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General Question On Object Methods
by tunacici7＠gmail.com 25 Sep '24

25 Sep '24

I've recently started to learn seL4 by following the Tutorials, which have been great so far. I've been also reading the Manual & API reference to understand and gain insight into different mechanisms. However, I have one fundamental question: Are the object methods system calls? It is said that seL4 only has 3 logical system calls: Send, Recv and Yield. (In all the slides, videos and other documents I have seen) And the rest is just variations of those ones. But what about object methods? Are they system calls? Are they executed in kernel space? If they are system calls, then wouldn't all the resources out there be misleading? Since there are way more than just Send, Recv and Yield. If they are not, then how are they handled? Does 'libsel4' have anything to do with it? I can't imagine 'seL4_Untype_Retype' executing in user space. Unfortunately, I couldn't find any answers to this question online. So that's why I'm asking it here. Maybe there are others who wonders the same thing. NOTE The API Reference page confuses me even more. It lists Object Methods in its own category (instead of being under System Calls). Does this means Object Methods are NOT system calls? Or the term System Call is just not what I think it is(basically an endpoint to kernel)?. END NOTE Thanks for the answers in advance. -T

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seL4 developer hangout reminder
by Birgit Brecknell 16 Sep '24

16 Sep '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Wed 18 Sep, 8:00am UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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Less than 1 week left to get the early-bird registration for the seL4 summit
by Birgit Brecknell 09 Sep '24

09 Sep '24

Less than 1 week left to get the early-bird registration for the seL4 summit The early bird cut-off date for the seL4 summit 2024 [0] is 15 September 2024. The summit will be held in Sydney, Australia, 15-17 October 2024. The seL4 summit will cover the complete seL4 ecosystem, consisting of the verified microkernel, as well as all seL4-related technology, tools, infrastructure, products, projects, and people. Tickets include: - Participation in the 3-day conference, including talks, keynotes, seL4 updates & discussions - Networking with other seL4 experts and enthusiasts - Reception and dinner Register here [1] A number of informal social activities [2] are being organised by local Sydney-siders. Check out the list [2] and contact the organiser to register your interest. [0] https://sel4.systems/Foundation/Summit/2024/ [1] https://events.linuxfoundation.org/sel4-summit/register/ [2] https://sel4.systems/Foundation/Summit/2024/social-activities Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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Virtual address ranges used in seL4 initial thread after boot?
by Ben McCart 06 Sep '24

06 Sep '24

I have read the manual in section 9.2 about userImageFrames and how to infer the virtual address range for the pages being used for the userland image, which I frankly do not concretely understand. For example, I can take the address of main() and that leads me to believe my first user image frame (page frame actually I suspect) is probably at 0x40000, but it feels like guessing. (Not good!) In addition, I like to know the address range used for the stack of the initial thread, as well as any other reserved regions (I read somewhere in the manual about reserved virtual address space for the kernel, but I can't remember where I read that and now I can't find it.) Are there any macros included in public header files that I can use in my project to get the starting addresses for any of these regions? Barring that, is there any straight-forward reliable way to find the starting address for these regions (or in the case of kernel reserved virtual address range is it documented anywhere?) I am on version 12.0 of seL4 for my project. Thank you! -Ben

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Less than 2 weeks left to get the early-bird registration for the seL4 summit
by Birgit Brecknell 02 Sep '24

02 Sep '24

Less than 2 weeks left to get the early-bird registration for the seL4 summit The early bird cut-off date for the seL4 summit 2024 [0] is 15 September 2024. The summit will be held in Sydney, Australia, 15-17 October 2024. The seL4 summit will cover the complete seL4 ecosystem, consisting of the verified microkernel, as well as all seL4-related technology, tools, infrastructure, products, projects, and people. Tickets include: - Participation in the 3-day conference, including talks, keynotes, seL4 updates & discussions - Networking with other seL4 experts and enthusiasts - Reception and dinner Register here [1] A number of informal social activities [2] are being organised by local Sydney-siders. Check out the list [2] and contact the organiser to register your interest. [0] https://sel4.systems/Foundation/Summit/2024/ [1] https://events.linuxfoundation.org/sel4-summit/register/ [2] https://sel4.systems/Foundation/Summit/2024/social-activities Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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seL4 developer hangout reminder
by Birgit Brecknell 02 Sep '24

02 Sep '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Tue 3 Sep, 10:00pm UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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seL4 developer hangout reminder
by Birgit Brecknell 19 Aug '24

19 Aug '24

Hi all A friendly reminder that the seL4 developer hangout is on again this week. Wed 21 Aug, 8:00am UTC. For your local date and time please see https://sel4.systems/contact/. Zoom link: https://unsw.zoom.us/j/82640784431 Birgit Brecknell seL4 Foundation Project Coordinator Sydney, Australia Mon 9-5 Wed 2-5 Fri 9-5 birgit(a)sel4.systems <mailto:birgit@sel4.systems> bbrcknl(a)gmail.com <mailto:bbrcknl@gmail.com>

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