Date: Wed, 22 Mar 2017 21:56:17 -0700 From: Warner Losh <imp@bsdimp.com> To: Julian Elischer <julian@freebsd.org> Cc: Allan Jude <allanjude@freebsd.org>, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Saurav Sachidanand <sauravsachidanand@gmail.com> Subject: Re: [GSoC 2017] Original proposal: Port kernel Lua to FreeBSD Message-ID: <CANCZdfptvkp6v5rgS6HMrA39P=5rHaJvNVC-WshRoJBiLpWFhA@mail.gmail.com> In-Reply-To: <9db670f6-54d1-7862-bcd2-7c80df92e724@freebsd.org> References: <CACKq%2BiX_V2MY9sNf-buEOO1S87dbhDv%2BPGbUEqRUVkvzz3pdvw@mail.gmail.com> <244231A2-EB18-4E58-A2B2-927F55D54950@FreeBSD.org> <CANCZdfpiiJLyLbEQnk86mfwf07JGByq5oT_1-T43iEhscEEgMg@mail.gmail.com> <f221e624-1342-7548-a3f9-806a1d25b90d@freebsd.org> <9db670f6-54d1-7862-bcd2-7c80df92e724@freebsd.org>
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On Wed, Mar 22, 2017 at 8:03 PM, Julian Elischer <julian@freebsd.org> wrote: > On 1/3/17 4:14 pm, Julian Elischer wrote: >> >> On 28/2/17 2:01 am, Warner Losh wrote: >>> >>> On Mon, Feb 27, 2017 at 8:26 AM, Allan Jude <allanjude@freebsd.org> >>> wrote: >>>> >>>> On February 27, 2017 5:28:41 AM PST, Saurav Sachidanand >>>> <sauravsachidanand@gmail.com> wrote: >>>>> >>>>> Hello FreeBSD community, >>>>> >>>>> I'm >>>>> Saurav Sachidanand, and I'm >>>>> a CS sophomore studying in India >>>>> . >>>>> I have an interest in operating systems development and wish to >>>>> contribute >>>>> to the FreeBSD community. I'm proficient with C and have some >>>>> experience in >>>>> kernel programming. Hence, I'd like to propose an original project for >>>>> GSoC >>>>> 2017 that I feel would benefit this community. >>>>> >>>>> In past years, the Lua interpreter was ported to run inside the Linux >>>>> and >>>>> NetBSD kernel [1]. Lua was chosen because it's interpreter is very >>>>> small (~240 >>>>> KB) compared to that of Python or Ruby, it's MIT licensed, and is >>>>> almost >>>>> freestanding. A working demonstration of it is a packet filtering >>>>> algorithm >>>>> written entirely in kernel Lua [2]. >>>>> >>>>> Specifically, my proposal would be to port the following that are >>>>> currently >>>>> written for NetBSD: >>>>> - the modified Lua VM source code with _KERNEL preprocessor directives >>>>> to >>>>> exclude user-space functionality like floating point, the io and os >>>>> module >>>>> in the standard library, etc. [3] >>>>> - the kernel module device driver for /dev/lua, to which Lua scripts >>>>> are >>>>> fed to be executed [4], [5] >>>>> - the luactl user-space program to control the Lua device and a couple >>>>> of >>>>> sysctl variables which serve similar purpose [6], [7] >>>>> >>>>> And then: >>>>> - run the Lua test suite targeting whatever we support in the kernel to >>>>> make sure it works [8] >>>>> - and write Lua bindings to the kernel interfaces that would interest >>>>> the >>>>> FreeBSD community >>>>> >>>>> Since NetBSD and FreeBSD have similar kernel interfaces (mutexes, >>>>> linked >>>>> lists, device switch interface), the porting shouldn't involve too much >>>>> code refactoring. Also, this would all be an experiment in that we >>>>> don't >>>>> fully know what the real world use cases might be, but it would attract >>>>> more people to writing kernel code who otherwise wouldn't because of >>>>> having >>>>> to do everything in C. And it would be interesting to carry out it out >>>>> in >>>>> FreeBSD as well since it has a larger community than NetBSD. >>>>> >>>>> I humbly request anyone who is interested in this project to be my >>>>> potential mentor(s) for GSoC. >>>>> >>>>> More slides on kernel Lua in NetBSD - [9], [10]. >>>>> >>>>> Thanks, >>>>> Saurav >>>>> >>>>> [1] - http://www.netbsd.org/~lneto/dls14.pdf >>>>> [2] - https://www.netbsd.org/~lneto/eurobsdcon14.pdf >>>>> [3] - https://github.com/jsonn/src/tree/trunk/external/mit/lua/dist/src >>>>> [4] - >>>>> https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/modules/lua >>>>> [5] - >>>>> >>>>> https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/modules/luasystm >>>>> [6] - https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sbin/luactl >>>>> [7] - http://netbsd.gw.com/cgi-bin/man-cgi?lua+4+NetBSD-current >>>>> [8] - http://www.lua.org/tests/ >>>>> [9] - >>>>> >>>>> https://www.netbsd.org/gallery/presentations/mbalmer/fosdem2012/kernel_mode_lua.pdf >>>>> [10] - https://www.lua.org/wshop13/Cormack.pdf >>>>> _______________________________________________ >>>>> freebsd-hackers@freebsd.org mailing list >>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-hackers >>>>> To unsubscribe, send any mail to >>>>> "freebsd-hackers-unsubscribe@freebsd.org" >>>> >>>> This may be quite a nice thing to have. Another upcoming use for LUA in >>>> the kernel is ZFS Channel Programs. These allow a number of ZFS operations >>>> to be completed as a single atomic transaction. >>>> >>>> I would hope we could structure this in such a way as to not end up with >>>> two copies of Lua in the kernel. >>> >>> There's also a 3/4 finished lua in the boot loader that you might be >>> able to leverage as well.... >> >> >> I'd like to see that finished. While Devin has done Heroic work with the >> forth in the loader, I think it's time has come. >> It' be nice to have something a little less '60s. > > some news: Pedro Arthur who did the project just mailed me: > > =================== > > Hi, > I've just finished getting the lua-bootloader code on top of HEAD, it should > compile and run fine. > The code can be found in [1]. > > [1] - https://github.com/grandao/freebsd/tree/projects/lua-bootloader > > =================== > so it's up to date and we should look at it again I did a rebase based of a few minutes ago. https://github.com/bsdimp/freebsd/tree/lua-bootloader and it's rebased off of freebsd:master rather than the old lua branch so will be easier to merge. There's also a bunch of commits that seem to be missing from grandao's tree. I need to get it compiling, and I can mine grandao's if there's issues... Warner
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