Date: Tue, 08 Mar 2016 14:47:54 -0700 From: Ian Lepore <ian@freebsd.org> To: Brad Walker <bwalker@musings.com>, Warner Losh <imp@bsdimp.com> Cc: "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: ? about kernel size.. Message-ID: <1457473674.1406.46.camel@freebsd.org> In-Reply-To: <CAPKZHbW%2BG7WnSU__yeYBVPqs8MPmFm-5q_wM4sm9FxHhEEgPDg@mail.gmail.com> References: <CAPKZHbVyPji-bZwDzM77TN6qybjRcf%2BZe5r6WZmbG98LkhT-rg@mail.gmail.com> <CANCZdfriqr24Lh9ZuptaC0gEm6gAV6LN9XHcVAJtbyaBejEgNg@mail.gmail.com> <CAPKZHbW%2BG7WnSU__yeYBVPqs8MPmFm-5q_wM4sm9FxHhEEgPDg@mail.gmail.com>
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On Tue, 2016-03-08 at 14:32 -0700, Brad Walker wrote: > On Tue, Mar 8, 2016 at 11:42 AM, Warner Losh <imp@bsdimp.com> wrote: > > > > > > > On Tue, Mar 8, 2016 at 10:42 AM, Brad Walker <bwalker@musings.com> > > wrote: > > > > > I'm looking at working on a new project that will use the FreeBSD > > > kernel. > > > I > > > would attempt to embed the kernel on a very small NXP Kinetis > > > chip. I've > > > previously done this using a Linux kernel but also had DDR memory > > > attached > > > to the chip. This project would not have a DDR chip attached. > > > > > > So a couple of questions. 1 - What is the smallest size I could > > > configure > > > the FreeBSD kernel out of the box? Could I get the size to be > > > less than > > > 10MB, 5MB, 2MB, or etc.? > > > > > > > I've managed to get this down to about 2MB or a bit smaller. > > Compressed > > this can be a little smaller. It takes a fair amount of work, but > > it can be > > done. > > > > > > That's great.. Was this out of the box tuning? > > > > > > I did a little bit of research on the PicoBSD and NanoBSD but that > > still > > > seem to be targeted to a little bit bigger chip than I have > > > available. > > > > > > > How big a chip do you have? NanoBSD currently needs at least > > 64MB (and ideally 128MB) of storage. PicoBSD can be a bit smaller. > > > > I have 2MB on-chip flash and 512KB of SRAM. There is an external > flash that > will be attached. What I'm currently thinking is that I would like to > boot > into BusyBox verses multi-user.. > > One question that I'm curious about. All the work that I do on this, > or > you've done in the past, how does it get integrated into the mainline > build. Wait a sec here... NXP Kinetis is ARM Cortex-M, and that means no MMU, right? No MMU means no freebsd running on it. -- Ian
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