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question about sel4 kernel preemptionPoint
by yadong.li 05 Jun '23

05 Jun '23

Hi: I have one question about sel4 kernel preemptionPoint on smp platform such as ARMv8. Take an example, when kernel takes long time to clear memory when UntypedRetype kernel object on core1, it will check preemptionPoint, when pending IRQ exists on core1, it will handle this irq, and return to userspace let other syscall or cores such as core2 have chance to run, but irq pending only check current cpu(PerCPU), no all cores of smp system, if core1 execute long seL4_Untyped_Retype syscall, core2 has a pending irq, the pending irq will not be checked in current core1, it will block until the execution of long syscall is completed if we take no account of archtimer irq, This phenomenon looks inconsistent at the system level between signal core and mutil core I want to know the current design intent about preemptionPoint of archtimer interrupt and other peripheral interrupts on SMP platform, only take current core interrupt as soon as possible or give other core and high priority task a chance to entry kernel and take big kernel lock? Thanks for your help

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seL4 Rust crates doc links broken
by Hugo V.C. 01 Jun '23

01 Jun '23

Hi all, was looking around the Rust crates to check what is available to play around with seL4 from Rust and just found that most interesting ones (sel4_sys, sel4-start, ...) have documentation pointing doc.robigalia.org which is a broken link. Looks like the only communication way to Robigalia is #robigalia IRC channel... (I don't use IRC since 90s, not used to it anymore...) so I'm publishing this info here as I bet those amazing developers are in this list too and can read this message: please 🙏 fix the link at crates.io. Beside this, I will never get tired of remember the importance of taking care of the "general public" (that is, common developers not familiarized with seL4, common companies that are not security nor technical gurus, etc... that is, the average potential user of seL4 in the future) so it has an "easy/friendly" approach to seL4 as an early adopter. For that reason, checking that (healthy) Rust environment is there available for everyone will be a good starting point. seL4 topic is complex enough with documentation, so without it becomes simply not usable (for humans... 😅). Hoping Robigalia amazing guys can read this here, thank you for your work on Rust, as this is the best interface to seL4 development for people living on this planet. Best,

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porting to a new platform
by steve.burke.56＠gmail.com 01 Jun '23

01 Jun '23

I'm trying to port an old sel4 code base to the latest so I decided to take the sel4test manifest & work through through the following page (https://docs.sel4.systems/projects/sel4/porting.html) The old code base does not add the new platform the same way since the new code seems to have some new CMake macros that do most of the heavy lifting. Is there a test project that does this with an arbitrary platform that I can use as a reference? My platform defines don't seem to be coming through correctly. Is working through the porting page the best way to do and does it seem current? Thanks.

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Reminder seL4 developer hangout
by Birgit Brecknell 29 May '23

29 May '23

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Wed, May 31, 7am (UTC), Topics: (open) * Sydney: Wed, May 31, 5pm * Central Europe: Wed, May 31, 9am * US Pacific Time: Wed, May 31, 12pm (midnight) Calendar: https://sel4.systems/contact/ Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

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Ring 3 iopl is going away, seL4 is ok
by William ML Leslie 21 May '23

21 May '23

Hello, I just noticed in the new x86-S rfc that Intel published that there will be no further support for io port access for processes in ring 3. Thankfully, this doesn't look like it will impact seL4, which provides capabilities to special objects representing port ranges on x86, which are then implemented in the kernel. Just in case anyone was wondering if there will be any impact, since this is the one thing that stuck out to me. Here's Intel's RFC: https://www.intel.com/content/www/us/en/developer/articles/technical/envisi… I think I might steal your IO port API for newer versions of Coyotos, which /is/ impacted by the change. TBF, I think seL4 has a better IRQ handling interface than the one we currently have too. I guess it's only fair it goes both ways! -- William ML Leslie

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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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Reminder seL4 developer hangout
by Birgit Brecknell 15 May '23

15 May '23

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Tue, May 16, 10pm (UTC), Topics: (open) * Sydney: Wed, May 17, 8am * Central Europe: Wed, May 17 12pm midnight * US Pacific Time: Tue, May 16, 3pm Calendar link: https://sel4.systems/contact/ Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

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Reminder seL4 developer hangout
by Birgit Brecknell 01 May '23

01 May '23

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Wed, May 3, 7am (UTC), Topics: (open) * Sydney: Wed, May 3, 5pm * Central Europe: Wed, May 3, 9am * US Pacific Time: Wed, May 3, 12pm (midnight) Calendar: https://sel4.systems/contact/ Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW birgit.brecknell(a)unsw.edu.au 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

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One week to go to submit a talk for seL4 summit 2023!
by Birgit Brecknell 17 Apr '23

17 Apr '23

One week to go to submit a talk for seL4 summit 2023 [0]! If you'd like to submit a talk, please upload an abstract of one page or less to the submission portal [1]. The seL4 Summit 2023 will be held 19 - 21 September 2023 at the Elliot Park Hotel, Minneapolis, USA. The summit will be hosted by the Linux Foundation, and will be an in-person event. Registration details to follow soon. We're looking forward to many exciting proposals! [0] https://sel4.systems/Foundation/Summit/2023/cfp [1] https://sel4.systems/Foundation/Summit/2023/submit --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

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Reminder seL4 developer hangout
by Birgit Brecknell 17 Apr '23

17 Apr '23

Hi all A friendly reminder that the seL4 developer hangout is on again this week: Tue, Apr 18, 10pm (UTC), Topics: (open) * Sydney: Wed, Apr 19, 8am * Central Europe: Wed, Apr 19, 12pm midnight * US Pacific Time: Tue, Apr 18, 3pm Calendar link: https://sel4.systems/contact/ Zoom link: https://unsw.zoom.us/j/82640784431 cheers Birg --- Dr. Birgit Brecknell Project Officer Trustworthy Systems, UNSW, birgit.brecknell(a)unsw.edu.au<mailto:birgit.brecknell@unsw.edu.au> seL4 Foundation, birgit(a)sel4.systems<mailto:birgit@sel4.systems> 0433 880 571 Mon 9am-5pm Wed 9am-12pm Fri 9am-5pm

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