Devel January 2016

devel@sel4.systems

17 participants
11 discussions

IA32 syscall bindings
by Norman Feske 26 Aug '16

26 Aug '16

Dear seL4 developers, first, I'd like to thank you for publishing seL4 under GPL. I am very happy that I can finally get my hands dirty with working with the kernel of your group. :-) Currently, I am taking the first baby steps to bring the Genode OS framework (http://genode.org) to seL4. For reference, I am using the experimental branch. The first smallish issue I stumbled upon stems from the fact that Genode is written in C++. By compiling the seL4 syscall bindings with a C++ compiler, I got the following error: error: inconsistent operand constraints in an ‘asm’ It can be reproduced by putting the following code snippet into a cc file and compiling it with 'g++ -m32 -c' (tested with the Genode tool chain as well as with GCC 4.8.1): typedef enum { seL4_SysDebugPutChar = -9, _enum_pad_seL4_Syscall_ID = (1U << ((sizeof(int)*8) - 1)) } seL4_Syscall_ID; void seL4_DebugPutChar(char c) { asm volatile ( "pushl %%ebp \n" "movl %%esp, %%ecx \n" "leal 1f, %%edx \n" "1: \n" "sysenter \n" "popl %%ebp \n" : : "a" (seL4_SysDebugPutChar), "b" (c) : "%ecx", "%edx", "%esi", "%edi", "memory" ); } When compiling the same code snippet with 'gcc' instead of 'g++', everything is fine. It turns out that the C++ compiler does not like the enum value to be specified as input argument. I found the following ways to circumvent this problem: * Changing the enum value 'SysDebugPutChar' to a positive value, * Removing the definition of '_enum_pad_seL4_Syscall_ID', * Casting 'seL4_SysDebugPutChar' to an integer: : "a" ((int)seL4_SysDebugPutChar), In any case, I seem to have to change the bindings. Do you see a way around it? If not, would you consider one of the solutions above for the seL4 headers? On another note, I noticed that the bindings use the EBX register. Unfortunately, this makes it impossible to compile seL4 userland software as position-independent code (PIC). E.g., when compiling the above code snippet via 'g++ -m32 -fPIC -c', the following error occurs: error: inconsistent operand constraints in an ‘asm’ However, PIC is required in order to use shared libraries. The solution would be to not use EBX to pass arguments to the 'asm' statements, save EBX on the stack prior moving the respective kernel argument to the register, and, of course, restoring it after sysenter returns. Before I start changing the bindings, I'd like to know: is there anyone else working on the same problem? Would you be open to accept a change of the bindings to become PIC compliant on the costs of a few added instructions? Or do you have another suggestion how I should go about it? Best regards Norman -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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Can not build RefOS
by Gapry Un 08 Mar '16

08 Mar '16

Dear all, I follow the official step (https://github.com/seL4/refos-manifest) to build RefOS and it occurs the following error message. In file included from /home/chi-wai/Workspaces/microkernel/RefOS/libs/librefos/src/sync.c:16:0: ~/Workspaces/RefOS/stage/arm/imx31/include/refos/refos.h:73:1: *error: unknown type name ‘uint32_t’* ~/Workspaces/RefOS/stage/arm/imx31/include/refos/refos.h:73:23: *error: unknown type name ‘uint32_t’* In file included from /home/chi-wai/Workspaces/microkernel/RefOS/libs/librefos/src/sync.c:18:0: ~/Workspaces/RefOS/stage/arm/imx31/include/refos-util/cspace.h:44:72: *error: unknown type name ‘uint32_t’* ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_create_mutex’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:49:5: *warning*: ‘seL4_Notify’ is deprecated (declared at /home/chi-wai/Workspaces/microkernel/RefOS/stage/arm/imx31/include/sel4/deprecated.h:23): use seL4_Signal [-Wdeprecated-declarations] ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_acquire’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:65:5: *error: invalid initializer* ~/Workspaces/RefOS/libs/librefos/src/sync.c: In function ‘sync_release’: ~/Workspaces/RefOS/libs/librefos/src/sync.c:74:5: *warning*: ‘seL4_Notify’ is deprecated (declared at /home/chi-wai/Workspaces/microkernel/RefOS/stage/arm/imx31/include/sel4/deprecated.h:23): use seL4_Signal [-Wdeprecated-declarations] make[1]: *** [src/sync.o] Error 1 make: *** [librefos] Error 2 Does RefOS use the old seL4 API ? If it is, which version I need to downgrade? Thanks for any help or suggestion, Gapry. https://gapry.wordpress.com/

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Upgrading to Camkes 2.0
by Jeff Hieb 26 Jan '16

26 Jan '16

I was looking to upgrade to CAmkES release 2.0. but can't get an example arm configuration to compile. I did a a fresh clone using https://github.com/seL4/camkes-manifest.git and found the ia32_simple_defconfig compiles fine, but not arm_simple_defconfig make arm_simple_defconfig make [libs/libsel4] building... make[1]: *** No rule to make target `/home/sysjeff/Camkes2/libs/libsel4/sel4_arch_include/arm/interfaces/sel4arch.xml', needed by `include/interfaces/sel4_client.h'. Stop. make: *** [libsel4] Error 2 looks like the arm directory got renamed to aarch32 and part of the build system doesn't know? $ ls /home/sysjeff/Camkes2/libs/libsel4/sel4_arch_include/ aarch32/ ia32/ Is there something simple I am missing? Thanks, Jeff -- Jeffrey L. Hieb Department of Engineering Fundamentals University of Louisville Louisville Kentucky 40292 (502) 852 0465

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Issue with CAmkES tutorial
by James Hasner 21 Jan '16

21 Jan '16

All, Noticed an issue with the tutorial for creating a dataport application with CAmkES components. This issue is on https://wiki.sel4.systems/CAmkES%20Tutorial within the Makefile and Kbuild section. You titled the application "helloevent" instead of hellodataport, causing the newly created application to not be able to access the header files needed. Thanks, James

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Announcing Robigalia, make seL4 applications with Rust!
by Corey Richardson 07 Jan '16

07 Jan '16

Hi all, On behalf of the Robigalia project I am pleased to announce our first public release of the core libraries for using Rust on seL4. Currently, this consists of a raw interface akin to libsel4 and a higher-level "Rustic" interface. Currently, only x86 is supported. An ARM port is in progress. We have a website: https://robigalia.org/ And a mailing list: https://lists.robigalia.org/listinfo/robigalia-dev The goal of the Robigalia project is to promote Rust as a robust choice for application development on seL4 and has the long-term goal of producing Robigo, a POSIX-compatible personality on seL4. We're in the initial stages of development. We are primarily a group of students from Clarkson University, though other contributors are starting to trickle in. Currently in-progress is a port of the tutorial from the sel4-tutorials repositories and examples of doing various things using the libraries we've created. Beyond those, we're also working on x86 platform support, right now virtio and PCI bus management. (I didn't intend on posting this for another week, to finish the tutorial and high-level library, but it was scooped on HN, so I figured I might as well) -- cmr +16032392210 http://octayn.net/

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Hardware Platform for sel4 and running linux as guest os
by Julien Delange 07 Jan '16

07 Jan '16

Dear all, I am looking to purchase a board for a project that will use sel4. I have the following hardware requirements: - serial port - ethernet - potentially usb Then, I want to run linux on top of sel4 and have also some native components. In the linux partition, I would like to control the usb and potentially the ethernet. In the native components, I am planning to use the serial port (communication with other components). I thought the beagleboard black would be a good match. Does anyone tried to run linux as a guest os on this platform? If yes, is there any tutorial/example to set it up? Also, any information about how to use the serial ports and other hardware components? Also, if you have an experience with any other board (x86 or ARM - the platform does not really matter), is it possible to indicate what you would recommend? Thanks for any help or suggestion, Julien.

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CAmkES 2.0.0
by Ihor Kuz 06 Jan '16

06 Jan '16

The Trustworthy Systems Team at Data61 (formerly NICTA) is pleased to announce CAmkES release 2.0.0 The new release updates CAmkES to be compatible with seL4 version 2.0.0. It also marks the transition to more frequent and regular releases, as well as switching our release process to semantic versioning, so it's easy to tell which CAmkES releases are source-compatible, or will require updates to user-level code, and also with which seL4 versions they will be compatible. You can find it at: https://github.com/seL4/camkes-tool/tree/2.0.0 And a manifest for the 2.0.0 compatible versions of the CAmkES test and example apps: https://github.com/seL4/camkes-manifest/blob/master/default-2.0.x.xml Enjoy! ________________________________ The information in this e-mail may be confidential and subject to legal professional privilege and/or copyright. National ICT Australia Limited accepts no liability for any damage caused by this email or its attachments.

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Extending errors to always include argument numbers
by Corey Richardson 05 Jan '16

05 Jan '16

For consistency, it seems like it'd beneficial if: seL4_RangeError seL4_AlignmentError seL4_DeleteFirst seL4_FailedLookup seL4_RevokeFirst included an indication of which argument the error applies to. For some of these errors, not every call has a unique argument which can cause the erorr. This seems like a relatively straightforward change for me to get acquainted with the full process of modifying and re-verifying the kernel. Are there tradeoffs hidden here that would make this undesirable? -- cmr +16032392210 http://octayn.net/

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seL4 & camkes questions
by Julien Delange 05 Jan '16

05 Jan '16

Hello, First of all, thanks for the help you provided previously. After downloading the virtual machine, everything was fine and I was able to try seL4 and camkes by using the tutorials. Thanks also for making this documentation available publicly, it definitively helps a lot to learn the principles of this operating system. I still do have some questions regarding sel4 and camkes. - About camkes, what are the thread mapping rules. How a component is transformed into one (or several) sel4 threads? Is there a mapping 1 component = 1 thread or is it possible to have multiple threads per component? - How can I find the code generated by camkes? The idl/adl code is ultimately transformed into C code and I was wondering where I could see the code. - How the real-time requirements are handled in camkes? For example, how can I specify that a component is executed periodically every XXX ms. Does the ADL supports that? - How can we specify the scheduling constraints? Can we have an ARINC653-like scheduling where every process has a fixed time slice to be executed? Since the behavior of the system can be deduced from the execution time, allocated a fixed time slice also avoid some attacks - About scheduling, what are the policies actually supported? - How timing is handled? I tried to use nanosleep() from the libc but it seems the syscall/service is not implemented. I also tried the timer example from the sel4 tutorial but when compiling, there is an error (the function timer_handle_irq needs an IRQ as a parameter). Any idea how to fix the example and more information about how time is handled? - is it possible for the OS to load and launch multiple elf at the same time or other processes must be manually started? - How capabilities and services are associated? From the example hello-2 in the sel4 tutorial, I see that a capability is declared (with vka_alloc_endpoint(&vka, &ep_object)) but I do not understand how this is associated with the message being sent between both tasks. In other words, how is it possible to associated a capability with a service. When sending or receiving a message (for example, by using seL4_SetMR(0, MSG_DATA);), there is no use of the capability. So, how the kernel can check that the thread can effectively send a message? - Is there any efforts to support standards such as ARINC653 or MILS? (even experimental) - Is there any significant/big projects that are available online and you would recommend to learn the OS and its associated libraries? Hope you do not mind such a list of questions! I really enjoy digging into the OS and it seems very interesting. Thanks for any help/comment.

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DMA
by Raymond Jennings 04 Jan '16

04 Jan '16

Is it ever possible for seL4 to run on a conventional machine without an IOMMU if any code that manipulates a DMA capable device is included as trusted or does DMA automatically void any assurance? Reason for question: Running seL4 on a system without an IOMMU.

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Devel January 2016