Date: Tue, 13 Mar 2018 13:19:15 +0530 From: Vishal Gupta <vishalgupta7972@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Michael Zhilin <mizhka@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: <CAKJMsQq4d-guaxr4-m6Md8OPQjSWJGBo6z2iPDiFu2ghmTZPgg@mail.gmail.com> In-Reply-To: <CANCZdfqUwoNO33PwftJJZ=f907jiCKDtY8Di7HFcD4Lqxi44_Q@mail.gmail.com> References: <CAKJMsQruOFPFOEbxEJnWajrnBucT_WHGiT9wQAy4v19PMcVxWQ@mail.gmail.com> <CAF19XBJeioko7S9AEr5=L%2B83FEowhPQyPKANd2TMHJAqSK_W0Q@mail.gmail.com> <CANCZdfqUwoNO33PwftJJZ=f907jiCKDtY8Di7HFcD4Lqxi44_Q@mail.gmail.com>
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Thank you for the reply. Which new processor would you suggest between PowerPC, ARM, and MIPS which i can port during the summer period and will also be useful for the community. Vishal Gupta On Tue, Mar 13, 2018 at 11:52 AM, Warner Losh <imp@bsdimp.com> wrote: > 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" >> > >
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