l4-hackers September 2001

l4-hackers@os.inf.tu-dresden.de

11 participants
11 discussions

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

1 0

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

1 0

L4 & Ada
by Frédéric BOYER 26 Sep '01

26 Sep '01

Hello, My project is not a real project in sens that it's only for fun. My main goal is to provide a little (R.T. if possible) Unix like O.S. as QNX or Plan9 on top of L4. I start on top of a micro kernel write in C, but if an Ada implementation exists (and works ;)), I will choose it will be choosen in priority. For now a study design concept of the O.S. By now, I follow exactly the User Guide Manual, with the typical OS example. I've created a sourceforge site & M.Ls. (search ADX). There is no traffic actually. Best regards .. Frédéric. ___________________________________________________________ Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr ! Yahoo! Courrier : http://fr.mail.yahoo.com

2 3

GNURL on top of L4
by Frédéric BOYER 25 Sep '01

25 Sep '01

Hello .. I'd like to find people here who can help me to build GNURL on top of L4 (GNAT Run time lib). I'd like to use L4 to develop an RT unix like O.S., but I'd like to implement it in Ada. Any people interested ? Is there people who know Ada here ? bye bye Frederic BOYER. ___________________________________________________________ Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr ! Yahoo! Courrier : http://fr.mail.yahoo.com

2 1

Re: GNURL on top of L4
by Michael Hohmuth 25 Sep '01

25 Sep '01

Frédéric BOYER <askliepios(a)yahoo.com> writes: > I'd like to find people here who can help me to build > GNURL on top of L4 (GNAT Run time lib). I'd like to > use L4 to develop an RT unix like O.S., but I'd like > to implement it in Ada. > > Any people interested ? Is there people who know Ada > here ? This sounds like a cool project. Do you envision a particular application, or are you interested in it just for hack value? Our group in Dresden currently has no ADA expertise or experience. However, depending on your project's focus, we might be willing to help out by directing students to your project and allowing them to earn credits this way. Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

1 0

Re: Recursive mapping trees?
by Jean Wolter 10 Sep '01

10 Sep '01

Martin Young <my(a)siroyan.com> writes: > Thinking it through however it's obvious that a task A can map a page P > to task B which can then map it back to task A at a different virtual > address. Is this allowed in L4? (I assume it is) Is it useful? Could > I get away with not allowing it? I ask because my initial > implementation includes a quick index from a taskid to a node in the > mapping tree (to avoid recursion rather than for speed) but this > requires that each task has only a single entry. L4Linux would not work on your L4 implementation, since we need more then one mapping for a page in the same address space to be able to implement vmalloc() and friends. To do this we currently map one page to a special helper task which immidiatly grants it back those creating a new mapping for the same page in the address space of L4Linux (we do this since for some reasons Jochen's L4 version didn't support intra task mappings, but I forgot the reasoning behind this design decision). Jean -- I get up each morning, gather my wits. Pick up the paper, read the obits. if I'm not there I know I'm not dead. So I eat a good breakfast and go back to bed. Peete Seeger

2 1

Recursive mapping trees?
by Martin Young 07 Sep '01

07 Sep '01

Hi, I've been adding mapping trees to my implementation of L4 and I have a question... The L4 reference manual states that address spaces are constructed recursively. Up 'till now I'd assumed that this was merely notional and that in real systems address spaces would be strictly n-ary trees, not graphs with cycles. Thinking it through however it's obvious that a task A can map a page P to task B which can then map it back to task A at a different virtual address. Is this allowed in L4? (I assume it is) Is it useful? Could I get away with not allowing it? I ask because my initial implementation includes a quick index from a taskid to a node in the mapping tree (to avoid recursion rather than for speed) but this requires that each task has only a single entry. Additionally, what effect should an unmap have: if task A unmaped P from task B, would the second mapping in task A disappear? I'd imagine that it would indeed remove the second mapping. I've had a look at the Fiasco souce and it wasn't clear to me where these situations are handled. Thanks. -- Martin Young, working for: | Phone: +44(0) 1454 615151 Siroyan Limited, Bristol Design Centre, | Mobile: +44(0) 7855 758771 West Point Court, Great Park Road, | web: www.siroyan.com Bradley Stoke, Bristol BS32 4QG. UK | email: my(a)siroyan.com ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com **********************************************************************

2 1

Race conditions
by Walt 07 Sep '01

07 Sep '01

Are there any papers that discuss the merits of microkernel and monolithic kernels in terms of race conditions? Regards Edsel __________________________________________________ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com

1 0

compilation errors
by rhim＠ufl.edu 05 Sep '01

05 Sep '01

Hi, while trying to compile the L4 system binaries and support servers, I ran into errors. Following is the snapshot of my system screen. --- make[2]: Entering directory `/root/Fiasco/l4/oskit/libc' gcc -c -MD -DHAVE_CONFIG_H -I. -I../libc/x86 -I../libc/stdio -I../libc/stdlib -I../libc/string -I../libc/gen -I../libc/malloc -I- -I.. -I.. -I../flux/c -nostdinc -DASSEMBLER -MD ../libc/x86/i16_bcopy.S /tmp/ccZPy7Kx.s: Assembler messages: /tmp/ccZPy7Kx.s:235: Error: `8(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:236: Error: `12(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:238: Error: `16(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:239: Error: `(%esi,%edx)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:242: Error: `(%edi,%edx)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:259: Error: `8(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:278: Error: `8(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:291: Error: `8(%ebp)' is not a valid 16 bit base/index expression /tmp/ccZPy7Kx.s:292: Error: `12(%ebp)' is not a valid 16 bit base/index expression ---- I am running Debian Linux 2.2.3 on pentium II on my laptop. Looking forward for help. Reagards, Himanshu

2 1

RE: L$Ka hazelnet kernel pnic
by Volkmar Uhlig 03 Sep '01

03 Sep '01

> When I boot l4ka-i586-dbg-vga (same problem happens with > l4ka-i686-rel-vga) I get a kernel panic. The message is: > startup.c:592: assertion failed (mbi->flags & MULTIBOOT_MODS) > > When I hit "k" to enter the kernel debugger, my machine > simply restarts and POSTs again, followed by my GRUB boot menu. Hi Karl, this sounds like you have problems with your version of GRUB. The error message you get is the resource manager complaining that you did not load any modules. Therefore, "k" reboots (bug/feature in RMGR) because no kernel is started yet. Try to run the ready-to-go grub image from http://i30www.ira.uka.de/~ud3/mkgrubdisk/. Volkmar PS: We try to keep L4Ka related technical problems off of l4-hackers. Please use l4ka(a)ira.uka.de instead.

1 0

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

l4-hackers September 2001