l4-hackers

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2827 discussions

Fiasco CVS repository
by Julian Stecklina 03 Sep '05

03 Sep '05

Hello, I have some problems with the CVS repository for Fiasco: cvs diff: failed to create lock directory for `/home/remote-cvs/l4/tool/twiddler' (/home/remote-cvs/l4/tool/twiddler/#cvs.lock): A file or directory in the path name does not exist. cvs diff: failed to obtain dir lock in repository `/home/remote-cvs/l4/tool/twiddler' cvs [diff aborted]: read lock failed - giving up Same goes with 'update' always in the twiddler directory. Regards, -- Julian Stecklina (Of course SML does have its weaknesses, but by comparison, a discussion of C++'s strengths and flaws always sounds like an argument about whether one should face north or east when one is sacrificing one's goat to the rain god.) -- Thant Tessman

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RE: Critics on L4 (NOT Re: shared memory Beispiel?)
by yuan Darwin-r62832 02 Sep '05

02 Sep '05

Hi, >Hi L4Ka::Pistachio developers, > >I have read the source code of L4Ka::Pistachio-0.4. & found that some >features defined in L4 eXperimental Kernel Reference Manual Version X.2 Revision 5 hasn't been implemented yet. For example, appoint redirector by SpaceControl, IO port mapping, etc. > > Please understand that both Pistachio and Fiasco are research prototypes and that the L4 eXperimental Kernel Reference Manual is indeed EXPERIMENTAL which means that it may change unnoticed and which also means that the prototypes may differ from the specification. The missing features that you state are published, e.g., at http://l4ka.org/projects/pistachio/ia32/ under the section Missing Features / Known Bugs for the Pistachio kernel , respectively at http://os.inf.tu-dresden.de/fiasco/status.html for Fiasco. [Darwin Yuan] Thanks for your information, I started to learn L4 just 1 month. A totally junior. Anything I was wrong, pls correct me. >I tried to checkout the newest source code from CVS, & the CVS server >cvs.l4ka.org couldn't be reached. > > I had no problems reaching the server. Though I cannot confirm that it was up all the time. [Darwin Yuan] Thanks, I'll try later. >When those features are going to be implemented? > Fiasco implements IO Flexpages. Neither Redirectors nor Clans and Chiefs are currently implemented in Fiasco and probably never will. I cannot speak for plans regarding Pistachio. [Darwin Yuan] I didn't read the source code of Fiasco. However, from the documents I got from its website, I found that Clans & Chiefs was implemented in its kernel ( It might be removed now). But I don't think it's a good design that this policy was involved in L4 kernel, now that L4 claims it's a real microkernel. However, I think those kind of policies could be implemented outside kernel. Therefore, I think Redirector is a good mechanism to achieve those kind of policies. That's why I think redirector is very important for implementing a flexible system on L4. >Now that those features are very important for implementing a flexible >OS on L4 u-kernel. > > Both redirectors and IO flexpages are not essential to get a system up and running. Their purpose is to control and restrict communication between threads respectively to prevent a thread from reading / writing IO-ports. Feel free to implement those features if you need them. [Darwin Yuan] Yes, That's true. However, a real system should makes peripheral equipment work. IO Fpage is very essential for implementing hardware driver. Can you elaborate on why you thing missing these features prevents someone building a flexible OS on L4? [Darwin Yuan] As mentioned above. >Seems that there are so many differences between L4Ka::Pistachio and >Fiasco. Is there a stardard L4 specification? > There is a standard L4 Specification: L4-V2 by Jochen Liedtke. Also there is the eXperimental specification you already found which is the defacto standard for L4-V4 kernels. The main difference between Pistachio and Fiasco is that the former implements L4-V4, the latter implements L4-V2 whereby some experimental features have been incorporated into Fiasco to better suite our user level software's needs. As you will see Fiasco already implements some parts of the L4-V4 specification. [Darwin Yuan] I see. Thanks. >I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so >many complicated & inflexible policies inside L4 kernel? > > Which policies are you referring to? Can you elaborate on these points? [Darwin Yuan] For example, Clans & Chiefs. Also, I think "Task" is a redundant abstract/concept, "Address Space" is a much better one. By "Thread" & "Address Space", L4Ka::Pistachio makes the abstract very refined, and allows to construct very flexible system. All together, the APIs of X.2 is much better than X.0. >BTW, has any OS or system been built on L4Ka::Pistachio? As I know, >L4-Linux is built on Fiasco, but I don't like its design. I hope I can >get a reference system based on L4Ka::Pistachio. > > > Lets see, there is L4 Linux which runs on both Fiasco and Pistachio, L4 Env, Drops runs on Fiasco, Kenge, Iguana and Wombat on Pistachio. Also there is Mungi, Perseus, L4 Hurd, etc. Have a look at l4hq.org and you may find out much more. [Darwin Yuan] Thanks for your information. Why don't you like the design of L4Linux or do you mean Fiasco? [Darwin Yuan] Actually, I don't like the APIs & mechanism of Fiasco. Now that L4Linux is based on those APIs & mechanism, I don't like this version of L4Linux. Some more final words: It is common practice on mailing lists to start a new topic if you are referring to a totally different topic. [Darwin Yuan] Honestly, I never use any public mailling list before:(. 'cause this original mail is the first mail I got from this mailing list, I replied it. Someone else has told me about that. Thanks anyway. Best regards Marcus -- Marcus Völp TU-Dresden Department of Computer Science Institute for System Architecture Tel: +49 (351) 463-38350 Fax: +49 (351) 463-38284

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RE: Critics on L4 (NOT Re: shared memory Beispiel?)
by yuan Darwin-r62832 02 Sep '05

02 Sep '05

Hi, Please see my comments below. -----Original Message----- From: l4-hackers-bounces(a)os.inf.tu-dresden.de [mailto:l4-hackers-bounces@os.inf.tu-dresden.de] On Behalf Of Adam Lackorzynski Sent: Friday, September 02, 2005 7:14 AM To: l4-hackers(a)os.inf.tu-dresden.de Subject: Re: Critics on L4 (NOT Re: shared memory Beispiel?) > Hi, > first, please use a proper quoting style. Your style is very unusual and irritating. First of all, I'd like to say that I won't use your "proper" quoting style, because that's just one of the styles which are used widely. In my mail system, the style which I used is set automatically. & more than 20,000 employees of our company around world are using this. If you don't like it, you don't have to read it. However, because this mail is a reply for you. To make you feel comfortable, I made the style as you want by HAND. Again, as I said before, I'm a junior of L4. However, I have been working in OS fields for many years. So, don't tell me any stupid knowledge & ask any stupid quesiton. On Wed Aug 31, 2005 at 21:00:16 +0800, yuan Darwin-r62832 wrote: > > > >When those features are going to be implemented? > > > > > >Fiasco implements IO Flexpages. Neither Redirectors nor Clans and > > >Chiefs > > >are currently implemented in Fiasco and probably never will. I cannot > > >speak for plans regarding Pistachio. > > >[Darwin Yuan] I didn't read the source code of Fiasco. However, from > >the documents I got from its website, I found that Clans & Chiefs was > >implemented in its kernel ( It might be removed now). But I don't > C&C were never implemented, and will never be, in any kernel. As I said, I didn't the source code of Fiasco, & will never be. Now that the documents declare that, I believed that. Thanks anyway for your telling me this. > think it's a good design that this policy was involved in L4 kernel, > now that L4 claims it's a real microkernel. However, I think those > kind of policies could be implemented outside kernel. Therefore, I > think Redirector is a good mechanism to achieve those kind of > policies. That's why I think redirector is very important for > implementing a flexible system on L4. > So what we have now are inflexible systems? If there isn't any inflexible system, why do we need microkernels? > > >Now that those features are very important for implementing a > > >flexible > > >OS on L4 u-kernel. > > > > > > > >Both redirectors and IO flexpages are not essential to get a system up > >and running. Their purpose is to control and restrict communication > >between threads respectively to prevent a thread from reading / writing > >IO-ports. Feel free to implement those features if you need them. > > > > [Darwin Yuan] Yes, That's true. However, a real system should makes > > peripheral equipment work. IO Fpage is very essential for implementing > > hardware driver. >Not having IO protection doesn't mean you cannot use drivers! Not having IO protection means that everyone >can whack your system because everyone runs with IO privileges, that's it. And you need to do this because >you cannot have drivers otherwise. We lived with that for some time but now we have proper IO protection so everything in fine in this regard. Of course I know we can use drivers by opening IO priviledges for all users. However, providing protection is a very essential responsibility for any secure OS. I'd pleased that you have achieved this. > > >I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so > > >many complicated & inflexible policies inside L4 kernel? > > > > > > > > > Which policies are you referring to? Can you elaborate on these > > >points? > > > >[Darwin Yuan] For example, Clans & Chiefs. Also, I think "Task" is a >That's not the fault of Fiasco, C&C is in the V2 spec. These are different things. And as already mentioned C&C where never implemented >as some clever guys noticed before that there are some problems. Everything I know about Fiasco is from V2 spec & other documents from Fiasco website. Frankly speaking, I don't like that spec. If that spec is the first L4 spec I read, I will definitely lost the interests in researching L4. Fortunately, X2 is the one. > >redundant abstract/concept, "Address Space" is a much better one. By >What's the difference between Task and AS? Task & AS are basically identical. However, when we talk about genenel OS concept, we will say that a Task has its own AS. & may owns some of threads. Even it's hard to figure out the difference, but that's the difference. L4 X2 spec use the AS concept instead of Task, will provide more flexible mechanism. For example, L4 X2 spec allows a non-interrupt thread migrated to another AS. If we use the concept "Task", this mechanism will cause confusion. Because from the point of general OS concept view, a thread transfers between Tasks is a little strange. That's why I think using the term "AS" is a better choice than using "Task". > >"Thread" & "Address Space", L4Ka::Pistachio makes the abstract very > >refined, and allows to construct very flexible system. All together, > >the APIs of X.2 is much better than X.0. >X.2 is the successor of V2/X0 so this is no real surprise. But in which way does the API decide how one's building flexible or inflexible systems? API is the interface provided by OS/kernel to outside. It's the reflection of OS/kernel mechanism. If a OS/kernel don't have a good support for build flexible system, can you easily do it? Another example, if hardware didn't provide MMU, can you easily implement VM? > >Why don't you like the design of L4Linux or do you mean Fiasco? > > > >[Darwin Yuan] Actually, I don't like the APIs & mechanism of Fiasco. > >Now that L4Linux is based on those APIs & mechanism, I don't like this > >version of L4Linux. > Cool. So what would I need to do to make it please you? Actually, you don't need anything. Because L4 x.2 & L4Ka::Pistachio are there. Thanks anyway. Adam -- Adam adam(a)os.inf.tu-dresden.de Lackorzynski http://os.inf.tu-dresden.de/~adam/ _______________________________________________ l4-hackers mailing list l4-hackers(a)os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers

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Re: shared memory Beispiel?
by Frank Mehnert 02 Sep '05

02 Sep '05

Hi Mathias, please send questions like this to l4-hackers in every case. Simply because I'm not the only one with knowledge about L4/L4-Userland. The other reason is that other L4 developers might be interested in such questions as well. On Wednesday 31 August 2005 10:03, you wrote: > ich versuche eine L4-Anwendung zu schreiben, die mit shared memory > arbeitet. Konkret soll ein Kernel-Thread in L4Linux-2.6 (ein > Netzwerktreiber-Stub) über den gemeinsamen Speicher mit einem L4-Task > (der ausgelagerte Netzwerktreiber) die zu sendenden, bzw. empfangenen > Rahmen austauschen. Ich hab schon im l4/pkg-Verzeichnis nach etwas > passendem gesucht, doch bin nicht wirklich fündig geworden, wie man dass > nun am Besten macht. > Ich will ja nur ein Stück Speicher fester Größe read/write für zwei > L4-Threads mappen. Muss ich dazu den Dataspacemanager benutzen, oder den > Regionmapper, oder gar l4io? Oder geht das vielleicht doch allein mit > den L4.V2-Systemrufen? I would suggest to use the dataspace manager dm_phys to allocate some memory and to map it into both L4Linux 2.6 and the native L4 task. Mapping into the native L4 task should be no problem as long this task has a region manager (the normal case for L4env tasks) -- simply attach the dataspace to the region manager. To map it into L4Linux 2.6, you have to reserve a range of virtual memory inside the Linux server (Adam, which function should someone use for this?) and then map it into that reserved region via l4dm_map_ds() (see dm_phys manual). Since L4Linux 2.6 makes havy use of L4env functionality, this function is available. Make sure that the whole dataspace is mapped into L4Linux since there is no region manager. Finally, make sure that both tasks have the right to map the dataspace. If the Linux server creates the dataspace it has to share the rights explicitly with the native L4 task with l4dm_share(). A more advanced approach would be to use the DSI (DROPS streaming interface) which is also available at the remote CVS. The DSI provides functions for synchronization between clients accessing the same dataspace. There is the dsi_example package. There might be comments from other people reading this list. > Entschuldige, dass ich Dich mit solch banalen Problemen störe, doch ich > weiß eben nicht, wie man das macht und die Dokumentationen (dm_mem, > dm_phys, L4-Referenzmanual, ...) sind dahingehend nicht gerade > aussagekräftig :/ IMHO there still were some threads about this on l4-hackers (please see http://os.inf.tu-dresden.de/mailman/listinfo/) Frank -- ## Dept. of Computer Science, Dresden University of Technology, Germany ## ## http://os.inf.tu-dresden.de/~fm3 ##

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RE: shared memory Beispiel?
by yuan Darwin-r62832 31 Aug '05

31 Aug '05

Hi L4Ka::Pistachio developers, I have read the source code of L4Ka::Pistachio-0.4. & found that some features defined in L4 eXperimental Kernel Reference Manual Version X.2 Revision 5 hasn't been implemented yet. For example, appoint redirector by SpaceControl, IO port mapping, etc. I tried to checkout the newest source code from CVS, & the CVS server cvs.l4ka.org couldn't be reached. When those features are going to be implemented? Now that those features are very important for implementing a flexible OS on L4 u-kernel. Seems that there are so many differences between L4Ka::Pistachio and Fiasco. Is there a stardard L4 specification? I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so many complicated & inflexible policies inside L4 kernel? BTW, has any OS or system been built on L4Ka::Pistachio? As I know, L4-Linux is built on Fiasco, but I don't like its design. I hope I can get a reference system based on L4Ka::Pistachio. Best Regards, Darwin Yuan -----Original Message----- From: l4-hackers-bounces(a)os.inf.tu-dresden.de [mailto:l4-hackers-bounces@os.inf.tu-dresden.de] On Behalf Of Frank Mehnert Sent: Wednesday, August 31, 2005 4:36 PM To: Mathias Krause Cc: l4-hackers(a)os.inf.tu-dresden.de Subject: Re: shared memory Beispiel? _______________________________________________ l4-hackers mailing list l4-hackers(a)os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers

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Re: gcc3.4 problem
by Leon Brits 31 Aug '05

31 Aug '05

Adam, This must be some Ubuntu thing since it compiles fine on a Gentoo box!? Any way now I get "Panic: deceiving ipc"-error after loading the console (l4con) and trying to start "run". Nothing else is loaded (see attachments). Thanks for all your support! Leon

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problem deploying l4env
by Christoph Mueller 25 Aug '05

25 Aug '05

Hello, I tried to build an l4env enabled simple hello world server, but I was not able to deploy it, because the l4env-servers did not start up. (Hello in sigma0-mode did work.) I have attached output from serial console and menu.lst from grub. Thanks, Christoph

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gcc3.4 problem
by Leon Brits 25 Aug '05

25 Aug '05

Hi all, Based on recent posts on this mailing list I decided to also give GCC 3.4 a go and ran into the following error when compiling l4linux-2.4: ljbrits@abc:/home/drops/DROPS/l4linux-2.4 $ make scripts/split-include include/linux/autoconf.h include/config gcc -D__KERNEL__ -I/home/drops/trunk/l4linux-2.4/include -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -gstabs+ -DLINUX_ON_L4 -I/home/drops/DROPS/l4/include/x86/l4v2 -I/home/drops/DROPS/l4/include/x86 -I/home/drops/DROPS/l4/include -DL4API_l4v2 -pipe -mpreferred-stack-boundary=2 -march=i686 -fno-unit-at-a-time -DKBUILD_BASENAME=main -c -o init/main.o init/main.c init/main.c: In function `init': /home/drops/trunk/l4linux-2.4/include/asm-l4/arch-i386/unistd.h:90: sorry, unimplemented: inlining failed in call to '__SC__open': function body not available init/main.c:105: sorry, unimplemented: called from here /home/drops/trunk/l4linux-2.4/include/asm-l4/arch-i386/unistd.h:89: sorry, unimplemented: inlining failed in call to '__SC__dup': function body not available init/main.c:104: sorry, unimplemented: called from here /home/drops/trunk/l4linux-2.4/include/asm-l4/arch-i386/unistd.h:89: sorry, unimplemented: inlining failed in call to '__SC__dup': function body not available init/main.c:104: sorry, unimplemented: called from here make: *** [init/main.o] Error 1 As I said I installed GCC3.4 on my system (Ubuntu 5.04) and changed all the symlinks in /usr/bin to point to the new installation of gcc and g ++. I made sure that everything was compiling just fine before installing the new compiler. Any suggestions? Thanks Leon

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Interrupt latency in L4Linux
by fabs0028＠free.fr 23 Aug '05

23 Aug '05

Hello, well i 'd like to measure the latency of the interrupts in l4linux, between the moment it is triggered in fiasco and the moment it is aknowledged in the top-halves of linux. Some hints would be greatly appreciated. Thanx for your help. Fabien Chaillou

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Re: l4-hackers Digest, Vol 28, Issue 13
by basant mudalgi 22 Aug '05

22 Aug '05

tanks

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