> On 03 Nov 2017, at 19:16, Danrae Pray <danrae.p...@metecs.com> wrote: > > Ok great - my followup question then is, if the COBALT kernel is itself a > modified linux kernel and it's the COBALT kernel that's patched with ipipe > (no patch is applied to the host kernel), how do POSIX API calls in > user-space code get mapped to the appropriate system call in the COBALT > kernel instead of the host linux kernel (in my case Ubuntu distro kernel)? > Does this magic happen at compile-time for the xenomai applications?
Yes. The magic is called symbol wrapping. See “—wrap” documentation of your linker (e.g. ftp://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_node/ld_3.html <ftp://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_node/ld_3.html>). When you use the xeno-config tool during compilation, it will set up the required flags. BR Christoph > > > > On Fri, Nov 3, 2017 at 12:59 PM, Lennart Sorensen < > lsore...@csclub.uwaterloo.ca> wrote: > >> On Fri, Nov 03, 2017 at 12:24:36PM -0500, Danrae Pray wrote: >>> I am trying to understand how the COBALT kernel is designed and how it >> can >>> be installed side-by-side various linux distro kernels (Gentoo, Ubuntu, >>> etc). >>> >>> During the COBALT kernel build process on Ubuntu, for example, we >> actually >>> pull a kernel version (based on your Ubuntu version) and build it: >>> >>> https://stackoverflow.com/questions/41949678/installation-steps-for- >> xenomai-3-on-ubuntu-16-04 >>> https://xenomai.org//installing-xenomai-3-x/# >> Configuring_and_compiling_the_Cobalt_kernel >>> >>> So, I guess my questions are: >>> >>> 1) At the end of the COBALT build / installation procedure as well as >>> installing the Xenomai libs/tools, can I actually use Xenomai in the >>> dual-kernel config on Ubuntu on my desktop PC for testing application >>> logic? i.e. I don't need to actually boot my machine using the newly >> built >>> image or something... >> >> You have to be running that kernel. >> >>> 2) Why are we building a linux kernel during the COBALT build process? >> Is >>> COBALT actually a modified linux kernel itself? >> >> Yes it is. The kernel is patched with ipipe and xenomai extensions to >> provide the required features. >> >> -- >> Len Sorensen >> > _______________________________________________ > Xenomai mailing list > Xenomai@xenomai.org > https://xenomai.org/mailman/listinfo/xenomai -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 842 bytes Desc: Message signed with OpenPGP using GPGMail URL: <http://xenomai.org/pipermail/xenomai/attachments/20171103/9b4c3515/attachment.sig> _______________________________________________ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
