- Devel - lists.sel4.systems

x86: loosing edge triggered interrupts when using I/O APIC
by Alexander Boettcher 24 Aug '16

24 Aug '16

Hi, we are using as user level timer driver the PIT on Genode/seL4 and experience situations that the driver does not get IRQs after a while. It happens on Qemu as also on native x86 hardware. We tracked down the problem to the masking of edge-triggered IRQs on the I/O APIC in the seL4 kernel. According to Intel, [0] chapter 3.2.4 "Interrupt Mask R/W", edge interrupts on a masked interrupt pin gets ignored and are not held pending. On [2] there are also some discussion about this topic too. We solved/workaround the issue by this patch [1]. I looked additionally into two other microkernels using the I/O APIC and they don't mask edge level triggered I/O APIC interrupts. I wonder if anybody already stumbled about the issue on seL4/x86? If not, please take the patch or give advices to adapt the patch so that it may get upstream. Thanks, Alexander Boettcher. [0] http://www.intel.com/design/chipsets/datashts/29056601.pdf [1] https://github.com/genodelabs/genode/blob/master/repos/base-sel4/patches/io… [2] http://yarchive.net/comp/linux/edge_triggered_interrupts.html

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New to seL4
by Andrew Mine 22 Aug '16

22 Aug '16

Hi I have just started looking at seL4 and I was wondering where can I find some documentation explaining the features and difference between seL4 and other kernels. I have gone through the manual and tutorial documents but nothing majorly explains how seL4 is different and its features. Any guidance towards any documentation will be helpful. Thanks Andrew

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next seL4 developers day on Sep 6?
by Gerwin.Klein＠data61.csiro.au 16 Aug '16

16 Aug '16

We’re contemplating running a seL4 developers day in conjunction with the DARPA HACMS PI meeting in Pittsburgh on Tue, Sep 6 2016. If you would be interested in attending, please drop me a short email by Thursday night of your local time zone. If enough people register interest we will try to organise one. Cheers, Gerwin -- Prof Gerwin Klein, Research Group Leader, Trustworthy Systems DATA61 | CSIRO gerwin.klein(a)data61.csiro.au T +61 2 8306 0578 http://data61.csiro.au NICTA and CSIRO’s Digital Productivity business unit have joined forces to create the digital powerhouse Data61

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Interrupt in seL4
by Norrathep Rattanavipanon 14 Aug '16

14 Aug '16

I have a few questions about how interrupts work in seL4. 1) Is it possible to enable/disable interrupt (i.e. __enable_irq or __disable_irq for ARM) in the userspace code of sel4? We want to make sure that the execution of the code in the initial process does not get interrupt. 2) My understanding is that the scheduling mechanism in seL4 is priority-based first and round-robin if two processes/threads have the same priority. Assume process A is the initial process spawned by kernel. 2.0) is my understanding about sel4 scheduling correct? 2.1) Is the initial process guaranteed to have the maximum priority in seL4? 2.2) If another process, say process B, is created by process A with lower priority. Is it possible for process B to interrupt process A and execute code in B instead while A is executing? Thanks, -- Norrathep (Oak) Rattanavipanon M.S. in Computer Science University of California - Irvine

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up-to-date formal verification
by Horace Blanc 09 Aug '16

09 Aug '16

Hi, I would like to know if the verification of the seL4 is up-to-date with the newest version of the sel4 microkernel (3.2.0). If so, how do I access it? When I run make ASpec in l4v, I get a pdf with the Abstract Formal Specification in version 1.3. Does it refer to the seL4 microkernel version 1.3 or has the Abstract Formal Specification its own versions? Also, what is the best way to explore this specification in Isabelle/jedit? thanks in advance Horace Blanc

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on Zynq
by Neelesh Vemula 08 Aug '16

08 Aug '16

Hi all, I am completely new with seL4, embedded systems as well as the fpga world. I am working on installing seL4 on Zynq fpga and use it. I have successfully able to boot up a "hello world" application using uboot(sd card bootup) on the zynq device. However, I have no clue as in how to setup communication between the sel4 logic and the PL(fpga fabric). If I am correct some sort of device driver has to be written or is there anything that is inbuilt or someone else who has worked on a similar project. Any guidance in this regard will be utmost helpful. Thanks a ton! Neelesh Vemula

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capDL configuration file
by Norrathep Rattanavipanon 03 Aug '16

03 Aug '16

So I was reading capDL paper and it mentions about having a human-readable XML file for configuration of the initial thread which allows the system initialize into a know state. I assume this is not specific to camkes. so is there any way I can see/get the XML file and the code that generates it in the regular seL4? Thanks, Oak -- Norrathep (Oak) Rattanavipanon M.S. in Computer Science University of California - Irvine

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memory map/unmap performance
by Yuxin Ren 02 Aug '16

02 Aug '16

Hi all, I am curious memory mapping/unmapping performance. Are there any applications that stress the memory mapping and unmapping utility? Thanks a lot! Yuxin

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beaglebone ethernet support
by Julien Delange 27 Jul '16

27 Jul '16

Hello, I noticed that there is some source code to support the ethernet driver of the beaglebone black. I look especially in projects/seL4_libs/libsel4platsupport/src/plat/am335x/cpsw_beaglebone.c According to https://github.com/seL4/seL4_libs/blob/master/libsel4platsupport/src/plat/a… the file has been introduced by NICTA - I am wondering if there is any existing example/support for it. In a nutshell, I am trying to use the ethernet driver. I started to integrate the startcode from TI on a camkes application before discovering this code. So, is there any sample application to use it? It is supported/working? Thanks for any help, Julien.

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sel4 on Hikey board
by rahul mahadev 26 Jul '16

26 Jul '16

Hi , I'm trying to run sel4 on a hikey board, I'm following this wiki https://wiki.sel4.systems/Hardware/HiKey . I'm having issues as the link to the linaro-edk2 patch does not work(asks for some auth) , can someone provide another link or direct me . Thank you

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