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L4 device-driver framework (was Re: vk_l4 -- CVS Setup)
by Michael Hohmuth 29 Oct '01

29 Oct '01

Farid Hajji <farid.hajji(a)ob.kamp.net> writes in l4-hurd: > [...] We'll probably also need glue code from OSKit to drop in the > driver framework from Michael. To clarify: There are two L4 device-driver frameworks that are currently in use, neither of which is ``Michael's framework.'' - One is a port of the OSKit to L4. It allows running OSKit applications on top of L4 in user mode, including applications that use OSKit's device drivers (which are mostly inherited from FreeBSD and Linux). It can be used to get applications up and running in short time on x86 machines, but it is somewhat slow, produces huge binaries (most of the time, the OSKit startup code links in *all* device drivers of a class) and is not portable (the OSKit really only runs on x86). Our distribution (available as part of our "l4" CVS module) includes a number of example programs lifted straight from the set of examples that came with the OSKit, including a "finger" client and a filesystem example. Here is the technical report I wrote on it: <URL:http://os.inf.tu-dresden.de/~hohmuth/prj/oskit-l4.ps.gz> - The other framework is a new development that is intended to fix the OSKit problems I mentioned, developed mainly by Christian Helmuth and Lars Reuther. This framework is intended to allow dropping the source code of one Linux driver inside it, recompiling, and ending up with a working L4 device driver. This framework does not use the OSKit (AFAIK), but is based on our new L4 environment, ``L4Env''. A prototype for character-device drivers exists, but hasn't been released yet. Preliminary L4Env docs: <URL:http://os.inf.tu-dresden.de/L4/bib.html#l4env> A description of the device-driver framework (Christian's diploma thesis, in German only): <URL:http://os.inf.tu-dresden.de/~ch12/sub/diplom.ps> Please bug the DROPS developers concerning releasing this stuff. :-) Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Is this list active?
by Ian Duggan 23 Oct '01

23 Oct '01

Is this list still active? Are there other L4 lists that I should be on as well? -- Ian ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ian Duggan ian(a)ianduggan.net http://www.ianduggan.net

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Re: Writing device drivers for L4 (was Re: Hurd/Mach on L4)
by Michael Hohmuth 14 Oct '01

14 Oct '01

Farid Hajji <farid.hajji(a)ob.kamp.net> writes: > > Currently, some of my colleagues are working on a framework that > > allows you to (more or less) drop a Linux driver in a preconfigured > > source tree and get a working driver that runs on the x86 L4 kernels > > (L4/x86, Fiasco, L4KA). This framework, which will work with the > > L4Env environment we're developing, is not quite ready yet, but it > > might be worth the wait. > > Will the drivers run in userland on top of a vanilla L4 kernel? Yes, they will. > I'm wondering wether it would be possible to use (RPC?) the driver > tasks directly from OS personalities like L4Linux, (L4BSD if someone > wants to repeat the Lites experience on L4 ;-)) or the Hurd, possibly > even simultaneously? Yes. We have been working on stub drivers for L4Linux that use external user-level drivers concurrently with (non-Linux) tasks. I'm not sure right now which stub drivers we currently provide, but I believe we already support console drivers and block-device drivers. > > As an alternative, consider using the OSKit. We have developed a > > compatibility library that allows you to run applications using the > > OSKit (including the OSKit's device drivers) on top of L4. This work > > is a bit unpolished and the drivers are slow, but it's quite easy to > > Good point. However, wouldn't it be necessary to link the driver > libs to the Kernel? This is exactly what we want to avoid in the > OSKit-Mach case sometime in the future (*Sigh*). No, the drivers run completely on user level. The OSKit has well-defined interfaces for low-level OS services such as IRQ allocation and delivery. Reimplementing these interfaces for a target system such as L4 (in particular parts of liboskit_dev and liboskit_kern) makes it possible to port OSKit drivers to the target system. OSKit drivers do not care whether they run on user level or in kernel mode if all services they expect from liboskit_dev and liboskit_kern are available. Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

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Writing device drivers for L4 (was Re: Hurd/Mach on L4)
by Michael Hohmuth 12 Oct '01

12 Oct '01

Farid Hajji <farid.hajji(a)ob.kamp.net> writes in l4-hurd: [...] > The second pressing point is to write/port a very small subset of device > drivers to L4. We need a native L4 driver for ATAPI (or SCSI?) disks, > so that the pager can use a real disk as backing store, and so that > we can port a filesystem as well ;). Here too, no-one volunteered yet. We in Dresden have extensive experience in porting Linux device drivers to run directly on top of L4, so if you guys have questions, don't hesitate to ask on the L4-hackers mailing list <l4-hackers(a)os.inf.tu-dresden.de>. Currently, some of my colleagues are working on a framework that allows you to (more or less) drop a Linux driver in a preconfigured source tree and get a working driver that runs on the x86 L4 kernels (L4/x86, Fiasco, L4KA). This framework, which will work with the L4Env environment we're developing, is not quite ready yet, but it might be worth the wait. As an alternative, consider using the OSKit. We have developed a compatibility library that allows you to run applications using the OSKit (including the OSKit's device drivers) on top of L4. This work is a bit unpolished and the drivers are slow, but it's quite easy to use. I even wrote a technical report on it: <URL:http://os.inf.tu-dresden.de/~hohmuth/prj/oskit-l4.ps.gz>. (You can find this and other reports in the L4 Developer's bibliography at <URL:http://os.inf.tu-dresden.de/L4/bib.html>.) Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Re: Cross Compile Needed?
by Michael Hohmuth 11 Oct '01

11 Oct '01

Ian Duggan <ian(a)ianduggan.net> writes: > I'm working to try to build the fiasco kernel for a pentium machine that > I have. I'm working from a Debian PIII. Will I need to build a > cross-compiler to produce code for the pentium machine? No, you can use your Linux installation's native compiler. > Working from the fiasco CVS, I can see how to invoke the --host options > for "configure" of oskit and oskit10. Is there anything similar for > doing this with the L4 module? No, the compiler L4 uses is configured in l4/Makeconf. On Linux/x86 systems, it's just `gcc', on other systems its usually `i386-linux-gcc'. Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Re: Code Repository
by Michael Hohmuth 11 Oct '01

11 Oct '01

Ian Duggan <ian(a)ianduggan.net> writes: > Who is the maintainer for the current L4/Fiasco CVS? If I have patches > to add to L4/Fiasco, to whom do I send them? The best place to send them to is the Dresden's bug-tracking system at <fiasco-bugs(a)os.inf.tu-dresden.de> (don't be fooled by the name -- use this address for L4- and Fiasco-specific changes alike). If your patches are Fiasco-specific, you can also send them for review directly to <fiasco-core(a)os.inf.tu-dresden.de>. Regards, Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Code Repository
by Ian Duggan 11 Oct '01

11 Oct '01

Who is the maintainer for the current L4/Fiasco CVS? If I have patches to add to L4/Fiasco, to whom do I send them? -- Ian ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ian Duggan ian(a)ianduggan.net http://www.ianduggan.net

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Cross Compile Needed?
by Ian Duggan 08 Oct '01

08 Oct '01

Hi, I'm working to try to build the fiasco kernel for a pentium machine that I have. I'm working from a Debian PIII. Will I need to build a cross-compiler to produce code for the pentium machine? Working from the fiasco CVS, I can see how to invoke the --host options for "configure" of oskit and oskit10. Is there anything similar for doing this with the L4 module? -- Ian ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ian Duggan ian(a)ianduggan.net http://www.ianduggan.net

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GNULLI
by Frédéric BOYER 27 Sep '01

27 Sep '01

Hello, I think that the best way to "port" GNAT on top of L4 is to port GNARL and rewrite GNULL lib. GNAT is the run time library but is almost portable. Modification in this package will be minor (Exception, interuption, etc). GNULL (Low Level lib) have to be rewritten entierly. Actually GNULL is port on Pthead lib & win thread. There are minor port to jtk (an other implementation of thread on linux computer .. it's a native one) or FSU. There are also port on micro kernel as Ravenskar or Mach (See MarteOS project). Maybe it could be cool to implements the GNULLI on top of L4, by define an interface beetween L4 & GNULLI to make it portable beetween implementation. After we could write some servers to implements the entire GNAT lib and Posix 1003.5 binding. But it's another story. Some specialized annexes could be implemented too (Real time, Distributed sys, etc.) best regards .. Frederic. ___________________________________________________________ Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr ! Yahoo! Courrier : http://fr.mail.yahoo.com

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gnarl on top of L4
by Frédéric BOYER 27 Sep '01

27 Sep '01

Hello, Just a little word about GNAT library design. GNAT lib is design over 3 layers. 1/ Applications 2/ The second layer (GNARL) is a threads independant manipulation lib. This lib is needed by the compiler and is the Run Time Lib of GNAT. 3/ the GNULL (Low level) is the OS/Hardware dépendant lib to implements Thread system. The lib is often build on Posix Thread. On W2000, this lib is implemented on top of win32 lib. Interface beetween Application & GNARL is called GNARLI, interface beetween GNARL & GNULL is called GNULLI. If you want to write servers in Ada with GNAT on top of L4, you can do it in several ways : 1/ Use pragma No_Run_Time. In this case, GNAT never use is lib. You can no more use task, hight level array fonctionnalities, .. see GNORT (no_run_time) documentation on adacore web site 2/ Implement the GNULLI interface. Ravenskar ORK use this way to port GNAT on their micro kernel. 3/ Implement the GNARL .. I gonna to choose the second way. Maybe we could defined a interface beetween GNULL & L4 to be hardware/kernel independ, to make our version of GNULL portable beetween L4 implementation. best regards .. Frederic. ___________________________________________________________ Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr ! Yahoo! Courrier : http://fr.mail.yahoo.com

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