Date: Tue, 13 Mar 2018 00:22:03 -0600 From: Warner Losh <imp@bsdimp.com> To: Michael Zhilin <mizhka@gmail.com> Cc: Vishal Gupta <vishalgupta7972@gmail.com>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: GSOC 2018 ARM Cortex Processor Message-ID: <CANCZdfqUwoNO33PwftJJZ=f907jiCKDtY8Di7HFcD4Lqxi44_Q@mail.gmail.com> In-Reply-To: <CAF19XBJeioko7S9AEr5=L%2B83FEowhPQyPKANd2TMHJAqSK_W0Q@mail.gmail.com> References: <CAKJMsQruOFPFOEbxEJnWajrnBucT_WHGiT9wQAy4v19PMcVxWQ@mail.gmail.com> <CAF19XBJeioko7S9AEr5=L%2B83FEowhPQyPKANd2TMHJAqSK_W0Q@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
There's not currently any other FreeBSD port that works on a system without a MMU. The buffer cache assumes that we can fault in pages as needed based on virtual address access. The TEXT sharing between programs assumes we can map the same page into multiple processes. The shared libraries we have assume something similar, and in some cases copy on write on top of that (though that's no different from a HW perspective than these first few cases). So, if you're willing to live without these features, or find some other way to accomplish the same sorts of things, a cortex M/R port would be tricky. Also, FreeBSD's kernel size may present some obstacles. We're optimized for a rich memory environment, so we trade extra copies of code to speed up execution of code, which matches the x86 market, as well as the high-end of embedded quite well. If you are looking for a BSD to port to these processors, you might consider looking at what www.retrobsd.org has done with their 2.11BSD port to the MIPS processor in the PIC32 core with the MIPS M4K architecture. It runs in as little as 128k of RAM, while FreeBSD these days needs at least 128MB of RAM without careful tuning... Warner On Tue, Mar 13, 2018 at 12:07 AM, Michael Zhilin <mizhka@gmail.com> wrote: > Hi, > > Disclaimer: I'm neither ARM expect nor GSoC person. > > I may be wrong, but FreeBSD (or Linux, doesn't matter) requires MMU which > is my tossing in Cortex M/R family of ARM processors. So it's technically > difficult/impossible to port it on non-MMU processor. > > Added freebsd-arm@ for wide audience. > > Thank you! > > > > On Tue, Mar 13, 2018 at 1:12 PM, Vishal Gupta <vishalgupta7972@gmail.com> > wrote: > > > Hi, > > I am interested in working on the project to port FreeBSD to ARM Cortex M > > or R series microprocessor. Some queries related to the project are :- > > 1) What are the expected deliverable for the project. > > 2) Where to put my draft proposal for review so that it can be improved. > > > > An early reply is awaited. > > > > Thanks and regards, > > Vishal Gupta > > _______________________________________________ > > freebsd-embedded@freebsd.org mailing list > > https://lists.freebsd.org/mailman/listinfo/freebsd-embedded > > To unsubscribe, send any mail to "freebsd-embedded-unsubscribe@ > freebsd.org > > " > > > _______________________________________________ > freebsd-embedded@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-embedded > To unsubscribe, send any mail to "freebsd-embedded-unsubscribe@freebsd.org > " >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CANCZdfqUwoNO33PwftJJZ=f907jiCKDtY8Di7HFcD4Lqxi44_Q>