Devel February 2019

devel@sel4.systems

8 participants
8 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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TLB issue
by Stefan Kalkowski 15 Nov '19

15 Nov '19

Dear sel4 community, yesterday I've started to develop a low-level platform test to stress several multi-processor aspects on top of the Genode API. Thereby, I've recognized that on sel4/x86_64 the TLB is practically not always cleaned properly in SMP systems. The test spawns threads of one protection domain on each available cpu. Each thread accesses one of the first words of a shared dataspace. Afterwards the main thread on CPU 0 detaches and destroys the dataspace. Unfortunately, the threads on other CPUs still successfully access the corresponding memory instead of triggering a fault. To be able to reproduce the problem, you might investigate the simple test case here: https://github.com/skalk/genode/commit/2d2d7f982555f551227ad5dcbf9df46705d7… My colleague Alexander Boettcher already investigated the problem in part, and might share his insights with you. Best regards Stefan -- Stefan Kalkowski Genode labs https://github.com.skalk | https://genode.org

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Sel4 for quadcore riscv64imafd
by Sreenadh S 03 Oct '19

03 Oct '19

I want to build sel4 for quadcore riscv64imafd and run the test programs, how to do that? Regards, Sreenadh S, CDAC, Trivandrum, India

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speed up sel4
by Sreenadh S 26 Mar '19

26 Mar '19

When running sel4 in my processor it is taking too long to get this line "vka_alloc_object_at_maybe_dev@object.h:65 Failed to allocate object of size 268435456, error 1" Is there any options to reduce allocation object size? Or any other methods to speed up Regards, Sreenadh S CDAC, Trivandrum, India

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ENTROPY 2019: Second Call for Papers
by Toby.Murray＠data61.csiro.au 20 Feb '19

20 Feb '19

NEW: two more invited speakers ********************************************************************** Second Call for papers — ENTROPY 2019 ENabling TRust through Os Proofs … and beYond Second International workshop on the use of theorem provers for modelling and verification at the hardware-software interface https://protect-au.mimecast.com/s/h5JtCjZroMFQkjkKFW-1Th?domain=entropy2019… Co-located with EuroS&P'19, KTH, Stockholm, June 2019 ********************************************************************** INVITED SPEAKERS Dominique Bolignano, Prove & Run Gernot Heiser, University of New South Wales Frank Piessens, KU Leuven Peter Sewell, University of Cambridge IMPORTANT DATES Paper submission: March 11 2019 Author notification: April 10, 2019 Camera-ready versions: April 22, 2019 (strict) Workshop: 16 June 2019 AIM AND SCOPE Low level software such as kernels and drivers, along with the hardware this software runs on, is critical for application security. In contrast with user applications, OS kernel software runs in privileged CPU mode and is thus highly critical. Large projects such as seL4, VeriSoft, CertiKoS and Prosper have invested considerable resources in developing formally verified systems such as hypervisors and microkernels, supplying proofs that they satisfy critical properties. Such proofs are delicate in terms of the scale and complexity of real systems, the models used in performing the proof search, and the relations between the two, which recent vulnerabilities such as Spectre and Meltdown have shown to be a highly non-trivial issue. The purpose of this workshop is to share, compare and disseminate best practices, tools and methodologies to verify OS kernels, also setting the stage for future steps in the direction of fully verified systems, dealing with issues related to modelling, model validation, and large proof maintenance through system evolution. On one hand, we need to make low-level proofs more scalable, modular and cost-effective. On the other hand, once certified systems are available, preservation and maintenance of their proofs of validity become key questions. The goal of the ENTROPY workshop is to provide a forum for researchers and practitioners in this space, linking operating systems, formal methods, and hardware architecture, interested in system design as well as machine verified mathematical proofs using proof assistants such as Coq, Isabelle and HOL4. This will be the second edition of the ENTROPY workshop series. The first workshop was organised by the Pip Development Team at University of Lille in 2018. TOPICS OF INTEREST Specific topics include, but are not limited to: * Verified kernels and hypervisors * Verified security architectures and models * Tools and frameworks for hardware security analysis * Tools and frameworks for security analysis * Formal hardware models and model validation techniques * Theorem prover based tools and frameworks for verification of low level code * Combinations of static analysis and theorem proving * Theories and techniques for compositional security analysis * Case studies and industrial experience reports * Proof maintenance techniques and problems * Compositional models and verification techniques * Proof oriented design The aim of the workshop is to stimulate innovation and active exchange of ideas, so position papers, work-in-progress and industrial experience submissions are welcome. SUBMISSION AND PUBLICATION There are two categories of submissions: 1. Regular papers describing fully developed work and complete results (10 pages, references included, IEEE format) 2. Short papers, position papers, industry experience reports, work-in-progress submissions (4 pages, references included, IEEE format) All papers should be in English and describe original work that has not been published or submitted elsewhere. The submission category should be clearly indicated. All submissions will be fully reviewed by members of the Programme Committee. Papers will appear in IEEE Xplore in a companion volume to the regular EuroS&P proceedings. For formatting and submission instructions see https://protect-au.mimecast.com/s/h5JtCjZroMFQkjkKFW-1Th?domain=entropy2019…. PROGRAM CHAIRS Mads Dam, KTH Royal Institute of Technology David Nowak, CNRS and University of Lille PROGRAM COMMITTEE Christoph Baumann, Ericsson AB Gustavo Betarte, Univ. de la República, Uruguay David Cock, ETH Zurich Mads Dam, KTH Royal Institute of Technology (chair) Anthony Fox, ARM Deepak Garg, MPI Saarbrucken Ronghui Gu, Columbia University Samuel Hym, Univ. Lille Thomas Jensen, INRIA and Univ. Rennes Toby Murray, Univ. Melbourne David Nowak, CNRS & Univ. Lille (chair) Vicente Sanchez-Leighton, Orange Labs Thomas Sewell, Chalmers

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Re: [seL4] port SeL4 to renesas rcar-H3 development board
by Diego Alejandro Parra Guzman 20 Feb '19

20 Feb '19

Hi guys !!! Thank you for your quick replay. I'm try to port Sel4 kernel to the* renesas H3 ULCB* board with two clusters (ARM57),(ARM53) each one with 4 cores I just have couple of questions regarding with the elf loader in sel4-tools: there is some files in* elfloader-tool/plat/** those are intended to initialize the CPU and the UART on the platform. In there, there is a function written in assembly called *core_entry_head* and a function *init_cpus*implemented in smp.c file. *Could you please explain me a little bit what is the purpose of these functions ? * In the case of *init_cpus* where is suppose to be that information? I means, I should reference the ARM57 or ARM53 cpu manual or maybe to the boot section in the SoC manual. from the other hand the *renesas H3 ULCB* doesn't have a physical UART port. Instead, it has an Serial Communication Interface with FIFO (SCIF) that can be configure properly to be compatible with *UART* interfaces. The point is that I'm using this interface in order to implement the * __fputc()* function following the one implemented in sys_fput.c file. Unfortunately, I don't understand why in your implementation there is not an initialization for the *UART. could you tell me why not?* Thank you. best regards On Sat, 16 Feb 2019 at 06:57, Diego Alejandro Parra Guzman < daparrag(a)correo.udistrital.edu.co> wrote: > Hi guys !!! > > Thank you for your quick replay. > > I'm try to port Sel4 kernel to the* renesas H3 ULCB* board with two > clusters (ARM57),(ARM53) each one with 4 cores > > I just have couple of questions regarding with the elf loader in > sel4-tools: > > there is some files in* elfloader-tool/plat/** those are intended to > initialize the CPU and the UART on the platform. In there, there is a > function written in assembly called *core_entry_head* and a function > *init_cpus*implemented in smp.c file. > *Could you please explain me a little bit what is the purpose of these > functions ? * > > In the case of *init_cpus* where is suppose to be that information? I > means, I should reference the ARM57 or ARM53 cpu manual or maybe to the > boot section in the SoC manual. > > > from the other hand the *renesas H3 ULCB* doesn't have a physical UART > port. Instead, it has an Serial Communication Interface with FIFO (SCIF) > that can be configure properly to be compatible with *UART* interfaces. > The point is that I'm using this interface in order to implement the > * __fputc()* function following the one implemented in sys_fput.c file. > Unfortunately, I don't understand why in your implementation there is > not an initialization for the *UART. could you tell me why not?* > > Thank you. > > best regards > > On Wed, 13 Feb 2019 at 15:21, Diego Alejandro Parra Guzman < > daparrag(a)correo.udistrital.edu.co> wrote: > >> >> Hi, >> >> I'm new with seL4 kernel and I would like to port it to the ARM-based >> renesas rcar-H3 board >> >> I would like to ask of you have a development manual that i can follow >> with some basics about how to do it? >> >> I followed the tutorials and so one. But I will appreciate if you have >> something guidelines to start. >> >> Thank you >> >> BR >> Diego. >> -- >> Diego Alejandro Parra Guzmán >> Estudiante de ingeniería electrónica >> Universidad distrital FJC >> > > > -- > Diego Alejandro Parra Guzmán > Estudiante de ingeniería electrónica > Universidad distrital FJC > -- Diego Alejandro Parra Guzmán Estudiante de ingeniería electrónica Universidad distrital FJC

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sel4 at Developers Conference 2019
by Jheengut Pritvi 14 Feb '19

14 Feb '19

Hi, I have been following and keeping track of the development of sel4 for more than 3 years. Unfortunately, I have not been able to install sel4 on my odroid U3 and it also has been a long time that I have built and run sel4. I am also part of the organising team of the Developers Conference since 2015 and this year is the fifth edition held in the Voila hotel and Flying Dodo in Bagatelle in the Republic of Mauritius. This year, I have a session about sel4. https://sessionize.com/s/jheengut/an_introduction_to_the_sel4_microke/21360 I would be highly pleased to have a piece of your opinion on this matter. Cheers Pritvi Jheengut

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port SeL4 to renesas rcar-H3 development board
by Diego Alejandro Parra Guzman 14 Feb '19

14 Feb '19

Hi, I'm new with seL4 kernel and I would like to port it to the ARM-based renesas rcar-H3 board I would like to ask of you have a development manual that i can follow with some basics about how to do it? I followed the tutorials and so one. But I will appreciate if you have something guidelines to start. Thank you BR Diego. -- Diego Alejandro Parra Guzmán Estudiante de ingeniería electrónica Universidad distrital FJC

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