l4-hackers

l4-hackers@os.inf.tu-dresden.de

2 participants
2880 discussions

23.10.1 amd64 l4linux doesn't build
by Richard Clark 12 Apr '24

12 Apr '24

Hi! I'm doing microkernel evaluations for a US gov't contract to find a nice shiny new replacement for the dismal little l4 microkernel they've been using and failing with... Fiasco/L4/L4linux seems to be a wonderfully full-featured software platform that easily fits the bill. Separation/Capability microkernel, fully developed user space, l4-native linux, and even a vmm that runs a sandboxed linux. Latest build with snapshot 23.10.1 and l4linux 23.10.1 seems the amd64 l4linux is broken with issues in libelf.h, gelf.h, and elf.h. 32bit build seems to build ok. Still trying to get something up and running. I'll try 32-bit with qemu for now. I do need 64-bit to compile and run, so I would appreciate any info on how to fix the build issues. Thanks! Richard H. Clark _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

3 6

uClibc and pthreads
by Pascal Scholz 25 Jan '24

25 Jan '24

Hello to all L4-Hackers out there, I'm currently investigating the pthread Implementation used in L4Re for an university project. To me it seems, that it's using Linuxthreads as pthread implementation of the uClibc. Regarding this I got two questions, of which I would be very happy, if someone could answer them: 1) Is there a technical reason for L4Re still using the Linuxthreads implementation and not some kind of NPTL port or other implementations? 2) What uClibc is used exactly? Do you manage your own fork of uClibc and back port relevant patches of uClibc-ng? Or do you use a uClibc-ng with additional L4 patches? Or some completely other version? It seems that the uClibc version used diverged in 2014 from the original. This seems relevant to me as I wanted to check, which changes were done to make the uClibc work with L4 (in an attempt to generate some kind of a diff), so I might port them to another libc implementation. In my project I would like to replace Linuxthreads with some other pthreads implementation and measure the performance impacts of these changes, so the aforementioned questions seem relevant to me. Thanks in advance for you time! Kind regards, Pascal _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

2 2

Which C++ version does Fiasco use
by teclis High Elf 29 Dec '23

29 Dec '23

Hi, There are a lot of C++ versions. Is Fiasco L4Re compliant with the current C++20 standard? regards, _______________________________________________ l4-hackers mailing list -- l4-hackers(a)os.inf.tu-dresden.de To unsubscribe send an email to l4-hackers-leave(a)os.inf.tu-dresden.de

3 2

CfP: Microkernel and Component-based OS Devroom at FOSDEM 2024
by Martin Decky 15 Nov '23

15 Nov '23

Microkernel and Component-based OS Devroom at FOSDEM 2024 CALL FOR PARTICIPATION On-line version of this CfP: http://fosdem.microkernel.info/ The developers and users of several free and open source microkernel-based, unikernel-based and component-based operating systems will meet as part of FOSDEM 2024 [1] and will share a developer room. The devroom is currently looking for content in the form of talks and other activities related to microkernel-based, unikernel-based, component-based operating systems and similar areas. Possible topics of the devroom include, but are not limited to: * introduction of a specific OS or framework * design of subsystems and the general architecture of an OS * languages, tools and toolchains used * enabling support for hardware (architectures, device drivers) and programming languages * development processes, debugging * maintenance, testing and release engineering * safety, security and robustness * trends and challenges * research and open questions * community and governance * use cases, experiences and status updates * best practices and lessons learned * demos The devroom has been scheduled to Saturday February 3rd 2024 in the afternoon (Central European Time). This is a call for your participation. We kindly ask you to submit your proposals no later than on December 10th 2023 (End of Day, Anywhere on Earth). Please use the pretalx [2] web site to submit your proposals. Note that this is a new submission system and the user accounts from the previous submission system (pentabarf) have not been transferred. Make sure to select the Microkernel and Component-based OS as the track when submitting your proposal and include at least the following information: * title of your proposal * short abstract (one or two paragraphs) * duration (at least 15 minutes and no longer than 40 minutes) * your full name * your short bio You can specify your preferred time slot of your proposal and any other relevant information. The communication language of the devroom is English. Please note that the devroom has been allocated only a half of a day this year. Therefore the final decision on the duration of the talks will be made by the devroom organizers based on the number of accepted proposals. The official devroom schedule (along with the accepted talks) will be announced on December 15th 2023 on the devroom's mailing list [3] and the speakers will be notified via e-mail. The schedule will be published on the FOSDEM web site, too. About the Devroom Since the first Microkernel OS Devroom at FOSDEM 2012 [4], this devroom has been a part of each following FOSDEM (with slight variations of the name). The focus gradually widened to include component-based, unikernel-based and other operating systems. By now, it has become a somewhat institutionalized tradition for the open source operating systems community, a kind of "extended family meeting" and it is one of the places where microkernel and unikernel enthusiasts meet regularly. To this date, over two dozen projects have participated in one way or another. Many of the projects face similar challenges but come up with partially different solutions. Therefore, the goal of the devroom is to bring the various projects together, let them exchange ideas, cross-pollinate and socialize. As every previous year, the devroom will offer the "stage" both to established community members and to newcomers. We like to select the talks in an inclusive manner, while staying true to the main technical topics (system-level software, broadly speaking) and creating a balanced and unbiased schedule. We would like to keep the quality bar of the devroom same as in the previous years. Presenting at FOSDEM implies that the recordings of the talks will be published under Creative Commons license by FOSDEM. By submitting a proposal, the speaker agrees to have the talk made available publicly indefinitely. For organizational purposes, we also need contact information of the speakers of accepted talks. Microkernel Dinner It has also become a habit that the devroom participants dine together somewhere in Brussels. The year 2024 will not be any different, so there is going to be a dinner on Saturday night. We will inform you about the exact arrangements later. About FOSDEM FOSDEM [5] is a two-day conference organized by volunteers to promote the widespread use of free and open source software. FOSDEM is widely recognized as one of the largest and best such events worldwide. FOSDEM covers a wide spectrum of free and open source software and hardware projects and offers a platform for people to collaborate. To this end, FOSDEM has set up developer rooms (devrooms) where teams can meet and showcase their projects. Devrooms are a place for teams to discuss, hack and publicly present latest directions, lightning talks, news and proposals. Besides developer rooms, FOSDEM also offers main tracks, lightning talks, certification exams and project stands. In recent years, FOSDEM has been hosting more than 8000 developers annually at the ULB Solbosch Campus in Brussels, Belgium. The participation in FOSDEM is totally free, although the organizers gratefully accept donations and sponsorship. No registration is necessary. Attendees are expected to follow the FOSDEM's code of conduct [6]. Important Dates Recap * 2023-12-10: Deadline for proposal submission * 2023-12-15: Schedule published and speakers notified of acceptance * 2024-02-03: Devroom taking place Contact For any comments, questions and suggestions, please do not hesitate to use the devroom's mailing list [3] to contact the devroom organizers. The primary organizers of the devroom in 2024 are: * Martin Decky * Razvan Deaconescu References [1] https://fosdem.org/2024/ [2] https://pretalx.fosdem.org/fosdem-2024/cfp [3] https://lists.fosdem.org/listinfo/microkernel-devroom [4] https://archive.fosdem.org/2012/schedule/track/microkernel_os_devroom.html [5] https://fosdem.org/ [6] https://fosdem.org/2024/practical/conduct/

1 0

L4Re: stack allocation of moderately large arrays
by Paul Boddie 13 Nov '23

13 Nov '23

Hello, Having seen a problem recur in programs running in L4Re just now involving arrays of a relatively large size allocated statically in functions - about 100000 bytes or so - I was wondering if there are any implicit limitations with this form of allocation in L4Re. Is it possible that programs have a limited stack size and that the stack does not expand? Here is an example of the kind of code that causes an unhandled exception: uint32_t Spi_gpio::send_units(uint32_t bytes, const uint8_t data[], uint8_t unit_size, uint8_t char_size) { uint32_t chars = bytes / unit_size; int dc[chars]; And the exception looks like this: Unhandled exception: PC=0x1019ca8 PFA=0xfffd075a LdrFlgs=0x0 The actual cause of the exception is an access to an element in the dc array. When I eventually get back to my own experiments with initiating programs in L4Re - not involved with the problem reported here - I intend to look more closely at program stack allocation and expansion strategies, so I suppose this is an appropriate prelude to such work. Thanks for any guidance that might be offered, as always! Paul

2 1

L4Re: Input via UART fails with Ned involvement
by Paul Boddie 19 Sep '23

19 Sep '23

Hello, I have been trying to get some sensible behaviour from various programs running in L4Re that wish to read from standard input, hopefully using the UART, since standard output is successfully sent across the serial connection. However, it appears that Ned does something rather undesirable with the input stream. If I modify the hello example to use fgets and deploy it without Ned (the hello.cfg example in conf/examples), as long as some kind of serial initialisation has occurred, I can enter characters at the serial console and have the program read them. However, if I deploy the same code using Ned (the hello.cfg example in conf/examples), fgets repeatedly returns NULL. Strangely, if I follow the instructions in the L4Re documentation... https://l4re.org/doc/l4re_servers_ned.html#l4re_ned_interactive The ned-prompt program itself just prints "Cmd>" over and over again, failing to read anything. It is as if non-blocking I/O has been enabled, although ned- prompt appears to use readline, so I imagine that there is likely to be a somewhat different explanation. Attempting to enforce non-blocking input using fcntl in the hello example also does not help. Has anyone any suggestions as to why these things do not work? I have tried this on physical hardware as well as in QEMU. Thanks in advance, Paul

2 3

L4Re uvmm guest OS
by Radu Aron 22 Aug '23

22 Aug '23

Hi, Is it possible to have a Windows guest OS running on top of L4Re? If so, could you provide some insight into how that could work? It seems like uvmm doesn't allow booting from an ISO image, or am I missing something?

2 1

ARM TrustZone with UVMM
by Michael Willig 11 Jun '23

11 Jun '23

Hi all, I would like to try Fiasco/L4Re for a Mixed-Critical Xilinx UltraScale+ FPGA-MPSoC (the hardware accelerators on the FPGA should be virtualized/isolated for mixed-critical applications) Is there somewhere an example (or at least starting point) of an ARM Trustzone configuration of a Normal World VM and Secure World VM (with UVMM/Fiasco as hypervisor that also takes care of the ARM Trustzone configuration)? Best regards Micha

2 1

L4Re: Allocating pinned memory and obtaining its physical address
by Paul Boddie 24 May '23

24 May '23

Hello, Sorry to be lazy and not dig too deeply into the documentation and code, but once upon a time it was possible to use the l4re_ma functions to allocate pinned memory. Then, one would use the dataspace protocol to obtain the physical address of the memory via the capability involved in memory allocation. This exercise would be sufficient to get into a position to initialise peripherals in a system-on-a-chip, setting registers with the physical memory addresses they would need for things like DMA. The initialisation of things like framebuffers would rely on this procedure. I see that the "phys" operation in the dataspace protocol was discarded some time ago, and now there is a "DMA space" abstraction instead: https://l4re.org/doc/group__api__l4re__c__dma.html Are there any examples of how I might obtain a physical address associated with a block of memory using this new API? Thanks in advance for any guidance that might be offered! Paul

3 5

L4Re: Boot module copying and the MIPS Creator CI20
by Paul Boddie 21 May '23

21 May '23

Hello, As part of reviewing my earlier efforts getting L4Re running on various MIPS- based devices, I have been trying to get the bootstrap module to start the kernel on the MIPS Creator CI20, and here I encounter a strange problem. The bootstrap code appears to copy the different modules in the payload around in memory, and for the kernel, it finds the different sections at 0x2f4000 in physical memory (accessed via 0x802f4000), copying them into locations relative to the indicated module base address (for example, 0x1100000 or 0x2000000). From their new locations, each section of the kernel is then copied to its desired final address. So, the section of the kernel providing its entry point can be found at 0x2f4000 + 0xa411c, this being copied to base + 0xa411c, before finally being copied to 0x800d3000. However, the contents of memory at the final location (0x800d3000) are not correct, nor are they at the "staging" location of base + 0xa411c, even though they do correspond to the expected contents of the kernel binary at their original location. What I expect to see at the entry point is... 40806000 mtc0 zero,c0_status 000000c0 ehb What I see instead is... ffffffff bea3ffdf Apart from at the original location in the payload (0x2f4000 + 0xa411c). As far as I can tell, the second word is nonsense, and it is usually followed by more ffffffff words. So, it is as if copying failed for this particular section. Oddly, this only seems to affect the section of the kernel providing the entry point, and all other sections appear to be copied correctly from their original locations. One factor might be that this section is the last one that is copied. Does this seem like recognisable behaviour of some kind of misconfiguration? For the most part, I am just rebasing my old patches on the current L4Re and Fiasco versions, so I didn't expect a problem at this level. Regards, Paul

3 12

← Newer
1
2
3
4
5
6
7
8
9
...
288
Older →

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

l4-hackers