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Trouble with semaphore library
by Marc CHALAND 24 Oct '07

24 Oct '07

Hello, I encounter strange problems with semaphore library from l4env. I use a vanillia revision 230 on an intel PIII architecture. After some debugging and tracing, I get the following scenarion : 1. thread 03 of my process calls a semaphore down timed which then calls BLOCKTIMED IPC to semaphore thread 02. So semaphore structure is: counter = -1 pending = 0 queue = 03 2. thread 08 calls semaphore_up inline assembler code. Before IPC call, the semaphore structure is as follow : counter = 0 pending = 0 queue = 03 3. Thread 03 gains the CPU after timeout and calls IPC RELEASETIMED : counter = 1 pending = 0 queue = empty 4. Thread 02 doesn't find thread into queue, so that pending is set to 1. counter = 1 pending = 1 queue = empty 5. Thread 03 calls semaphore_down. No IPC is called. counter = 0 pending = 1 queue = empty 6. Thread 03 calls semaphore_down again and IPC BLOCK is called. IPC awakes imediately 03 with a counter value of -1 and nobody into queue. counter = -1 pending = 0 queue = empty It seems to me that this state is not normal. Do you agree ? Is this scenario possible as I observe clearly state 4 5 and 6 ? What pending is for ? Thanks in advance for your answers. Marc

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Re: l4-hackers Digest, Vol 54, Issue 9
by 丁莹 17 Oct '07

17 Oct '07

2007/10/16, l4-hackers-request(a)os.inf.tu-dresden.de < l4-hackers-request(a)os.inf.tu-dresden.de>: > > Send l4-hackers mailing list submissions to > l4-hackers(a)os.inf.tu-dresden.de > > To subscribe or unsubscribe via the World Wide Web, visit > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > or, via email, send a message with subject or body 'help' to > l4-hackers-request(a)os.inf.tu-dresden.de > > You can reach the person managing the list at > l4-hackers-owner(a)os.inf.tu-dresden.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of l4-hackers digest..." > > > Today's Topics: > > 1. Re: The keyboard problems (Adam Lackorzynski) > 2. Re: L4Linux and weird newlines (Adam Lackorzynski) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 16 Oct 2007 00:30:30 +0200 > From: Adam Lackorzynski <adam(a)os.inf.tu-dresden.de> > Subject: Re: The keyboard problems > To: l4-hackers(a)os.inf.tu-dresden.de > Message-ID: <20071015223030.GR19315(a)os.inf.tu-dresden.de> > Content-Type: text/plain; charset=iso-8859-1 > > > On Mon Oct 15, 2007 at 12:18:37 +0800, ???? wrote: > > My keyboard is the normal ps/2 AT keyboard and I have enabled the all > kind > > of keyboard drivers in l4linux,but the things again,the state is that I > have > > logged in the l4linux and the prompt have appeared,but the cursor is > > flashing in the head of the prompt,not in the back of the #.And I have > try > > the init=/bin/sh option in my command line ,but the keyboard isn't > working > > as before.The attachment is my l4linux's configuration file.Thanks a lot > for > > you help! > > So, looking at the config file, you neither have VGA_CONSOLE switched on > nor L4_FB_DRIVER. So how does your setup look like? I guess that's why > you're actually not seeing anything really useful on the screen. So how > about enabling VGA_CONSOLE? > > > Adam > -- > Adam adam(a)os.inf.tu-dresden.de > Lackorzynski http://os.inf.tu-dresden.de/~adam/ I hava enabled the VGA_CONSOLE,and could saw some chang when starting,just like some words's color turned normal,but the keyboard didn't working sitll.Then I enable the L4_FB_DRIVER,but it can't compile right,the error message like this: arch/l4/kernel/main.c:80:5: warning: #warning WARNING: L4FB enabled and also CONFIG_SERIO_I8042 or CONFIG_SERIO_LIBPS2 or CONFIG_VGA_CONSOLE arch/l4/kernel/main.c:81:5: error: #error WARNING: This is usually not wanted. make[1]: *** [arch/l4/kernel/main.o] error 1 make: *** [arch/l4/kernel] error 2 and I used ubuntu-6.06 with gcc version gcc-4.0.3. There seems some problem in my configuration,but I can't solve it. Could you show me with your l4linux config file? Best Regards! ding ------------------------------ > > Message: 2 > Date: Tue, 16 Oct 2007 00:32:50 +0200 > From: Adam Lackorzynski <adam(a)os.inf.tu-dresden.de> > Subject: Re: L4Linux and weird newlines > To: l4-hackers(a)os.inf.tu-dresden.de > Message-ID: <20071015223250.GS19315(a)os.inf.tu-dresden.de> > Content-Type: text/plain; charset=iso-8859-1 > > Hi, > > On Mon Oct 15, 2007 at 09:38:35 +0200, Stefan Scheler wrote: > > I'm getting lots of weird newlines in L4Linux. Where do they come from > > and how do I turn them of? Here's a simple example which shows the > problem: > > > > localhost ~ # dd if=/dev/urandom of=/dev/null count=100 > > 100+0 records in > > 100+0 records out > > 51200 bytes (51 kB) copied, 0.0262116 s, 2.0 MB/s > > localhost ~ # dd if=/dev/urandom of=/dev/null count=1000 > > > > > > 1000+0 records in > > 1000+0 records out > > 512000 bytes (512 kB) copied, 0.274718 s, 1.9 MB/s > > localhost ~ # dd if=/dev/urandom of=/dev/null count=2000 > > > > > > > > 2000+0 records in > > 2000+0 records out > > > > 1024000 bytes (1.0 MB) copied, 0.580115 s, 1.8 MB/s > > localhost ~ # > > > > The higher the count value is, the more new lines I get. It's often > > impossible to see any actual output messages. > > I'm occasionally seeing this with slow hosts on Fiasco-UX. What's your > setup? > > > > 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 > > > End of l4-hackers Digest, Vol 54, Issue 9 > ***************************************** >

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L4Linux and weird newlines
by Stefan Scheler 17 Oct '07

17 Oct '07

Hello, I'm getting lots of weird newlines in L4Linux. Where do they come from and how do I turn them of? Here's a simple example which shows the problem: localhost ~ # dd if=/dev/urandom of=/dev/null count=100 100+0 records in 100+0 records out 51200 bytes (51 kB) copied, 0.0262116 s, 2.0 MB/s localhost ~ # dd if=/dev/urandom of=/dev/null count=1000 1000+0 records in 1000+0 records out 512000 bytes (512 kB) copied, 0.274718 s, 1.9 MB/s localhost ~ # dd if=/dev/urandom of=/dev/null count=2000 2000+0 records in 2000+0 records out 1024000 bytes (1.0 MB) copied, 0.580115 s, 1.8 MB/s localhost ~ # The higher the count value is, the more new lines I get. It's often impossible to see any actual output messages. Any help greatly appreciated. -- Stefan Scheler

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about the L4Linux scheduler
by Lin 17 Oct '07

17 Oct '07

Hello. I have some questions about the scheduler system on DROPS L4Linux. I would like your help or some hints. The version of my source is ... DROPS SVN revision : 205 L4Linux SVN revision : 61 Fiasco version : 1.2 L4Linux version : 2.6.22 In L4Linux system (on L4Env), there are two schedulers (in Fiasco and in Linux server), you know. Some papers say any Linux user process consists of L4 task and the L4 shceduler schedules all L4 thread. It is ok, but I can't understand the work of the Linux scheduler. In fact, a new thread is created in L4 when a process (has one thread) is created in Linux, and the active thread is changed when the context switch occurs in Linux server (made sure by using Fiasco JDB). I want to make this relation clear. In other words, what does the Linux scheduler do at these time. 1. Task creating ~~~~~~~~~~~~~~~~ When "fork()" (or such functions) is called, the function: l4x_setup_next_exec (in "arch/l4/kernel/arch-i386/dispatch.c") may be called. This function seems push the argument function "ret_from_fork" to the stack of the new "task_struct" instance to execute it first when the task is scheduled. Then, when "fork()" ends (when "do_fork()" returns), the new "task_struct" instance is created in Linux system. At this time, is the L4 thread (task ?) corresponds to that "task_struct" is not created yet ? (I assume it is created after the "task_struct" is scheduled.) 2. Linux server's scheduling ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In L4Linux task, there are 7 threads and IRQ threads: (1)l4lx.rm (2)l4lx.sem (3)l4lx.main (4)l4lx.tamer (5)l4lx.cpu0 (6)l4lx.timer.i0 (7)l4lx.idler ... "l4lx.main" creates "l4lx.cpu0" (Linux server) and waits this end. "l4lx.cpu0" does many initialization in the function "start_kernel()", and then it reaches at the function: l4x_idle (in "arch/l4/kernel/dispatch.c"). In this function, the Linux server creates the thread "l4lx.idler" and then enters the scheduling and IPC waiting loop. What does this function do ?? (My expectation about it is written in 4.) And more, What is the thread "l4lx.idler" used for ?? 3. Scheduled new Linux task ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The function "switch_to()" (depends on L4 arch) in Linux kernel only saves and restores the registers ESI, ..., ESP, and EIP. So, when all new created "task_struct"s are scheduled by the Linux server, they runs from "ret_from_fork" as the Linux server thread. (Is it right ?) ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^ "ret_from_fork" reaches at the function: l4x_user_dispatcher (in "arch/l4/kernel/dispatch.c"). It calls "l4x_spawn_cpu_thread()" before its loop. I assume it creates the new L4 thread corresponds to the now scheduled "task_struct" in Linux server. And, the loop in "l4x_user_dispatcher" seems to reply or wait page fault, exception and system call IPCs from any L4 thread runs as a Linux user task. What does this loop do in fact ?? When the context switch occurs in Linux server for some reasons, the active L4 thread is also switched almost at the same time. (I see it by using "ps" on Linux and the thread list of JDB on L4.) I want to know the mechanism of this synchronization. 4. Summary ~~~~~~~~~~ My main quiestions is ... (1) What is "l4lx.idler" created for ? (in 2) (2) What does the function "l4x_idle" do ? (in 2) (3) Do all Linux user tasks ("task_struct" instance) only execute "l4x_user_dispatcher" (from "ret_from_fork") as the Linux server ? (in 1 and 3) (4) What does the function "l4x_user_dispatcher" do ? How to switch contexts in Linux and in L4 almost at the same time ? (in 3) My expectation about Linux scheduling system is the following: - When there is no need to reschedule Linux user processes, Linux server is in IPC sleep and waiting the wakeup IPC in "l4x_idle". - If Linux server gets IPC for some reasons, it wakes up and check the IPC sender. Then, if the sender is a thread corresponds to certain Linux task, Linux server wakes up this Linux task and reschedules by calling "schedule()". - The waked up task will be active as Linux server. This context may execute only "l4x_user_dispatcher" which replies and wait IPCs and handles page faults and exceptions based on information of the received IPC. - When the L4 thread of the Linux task exits, that Linux task in Linux (task_struct instance) also is freed. If there is no schedulable task in Linux at that time, the original context (executes "l4x_idle") is re-scheduled. If you find my incorrect understanding, please tell me. Sorry for my poor English and lengthy question. I'm glad if you give me some hints or corrections. Regards, Lin (a college student in Japan)

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The keyboard problems
by 丁莹 15 Oct '07

15 Oct '07

Hi,adam! My keyboard is the normal ps/2 AT keyboard and I have enabled the all kind of keyboard drivers in l4linux,but the things again,the state is that I have logged in the l4linux and the prompt have appeared,but the cursor is flashing in the head of the prompt,not in the back of the #.And I have try the init=/bin/sh option in my command line ,but the keyboard isn't working as before.The attachment is my l4linux's configuration file.Thanks a lot for you help! Best Regards! ding

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why the keyboard can't use?
by 丁莹 14 Oct '07

14 Oct '07

Hi!all I recompiled l4linux-2.6.22 and disabled any dope options,then started l4linux in console ttyLv0,38400,and the prompt appeared,but the keybodard can't using.I have choosed the keyboard options,but the problem is still,what problem causing that?Everyone know this,please help me!Thanks a lot! Best Regards!

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what console options should using in the linux26.cfg
by 丁莹 14 Oct '07

14 Oct '07

Hi!all When I want to start the l4linux in serial port and used console options as this:console=ttyS0,115200,There is some strange message appeared both in serial port and native screen as follow: io | Available IRQs=[ <!0> 1 <!2> 3 <!4> 5 6 7 8 9 a b c d e f 10 11 ] l4lx | ======> L4Linux 2.6 starting... <======== l4lx | Linux version 2.6.22-l4 (cheng@dingy-desktop) (gcc version 4.0.3(Ubu l4lx : ntu 4.0.3-1ubuntu5)) #3 Wed Oct 10 11:43:39 CST 2007 l4lx | Binary name: vmlinuz l4lx | Kernel command line (6 args): earlyprintk=yes console=ttyS0,115200 in l4lx : it=2 mem=64M root=/dev/hda2 ro l4lx | Console output set to ttySx. Not recommended. And then I changed console options in linux26.cfg to:console=ttyLv0,38400,It showed the right l4 start message just like: ............................................................................................. l4lx | l4lx_irq_dev_startup_hw:Starting IRQ thread for IRQ 12. l4lx | l4lx_thread_create:Created thread 0f.0a(IRQ12) l4lx | l4lx_irq_dev_startup_hw:Starting IRQ thread for IRQ 1. l4lx | l4lx_thread_create:Created thread 0f.0a(IRQ1) l4lx | l4lx_irq_dev_startup_hw:Starting IRQ thread for IRQ 11. l4lx | l4lx_thread_create:Created thread 0f.0a(IRQ11) in last,but It can't turn to the l4linux starting,What the problem? Eeveryone know this please help me,Thanks a lot! Best Regards!

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Fwd: The problem of grub-0.97 install
by li fei 14 Oct '07

14 Oct '07

---------- Forwarded message ---------- From: li fei <tezuka158(a)gmail.com> Date: 2007-10-12 下午12:00 Subject: The problem of grub-0.97 install To: l4 <l4-hackers(a)os.inf.tu-dresden.de> Hi!all, When I compiled the grub, I met some problems. I patched the patches which I down from the http://os.inf.tu-dresden.de/~adam/grub/0.97/<http://os.inf.tu-dresden.de/%7Eadam/grub/0.97/> . I patched the patches from the grub-0.97-os.1.diff to the grub-0.97-grub-0.97-os.5.diff, and I found they all have mistakes, the error from the grub-0.97-os.2.diff to the grub-0.97-os.5 were the same.Below are the errors: pre_stage2_exec-bios.o : In function `get_cdinfo': /home/l4/Desktop/grub-0.97/stage2/bios.c:179: undefined reference to `__stack_chk_fail' pre_stage2_exec-bios.o: In function `get_diskinfo': /home/l4/Desktop/grub- 0.97/stage2/bios.c:317: undefined reference to `__stack_chk_fail' pre_stage2_exec-boot.o: In function `load_image': /home/l4/Desktop/grub-0.97/stage2/boot.c:759: undefined reference to `__stack_chk_fail' pre_stage2_exec-builtins.o: In function `blocklist_func': /home/l4/Desktop/grub-0.97/stage2/builtins.c:224: undefined reference to `__stack_chk_fail' pre_stage2_exec-builtins.o: In function `embed_func': /home/l4/Desktop/grub-0.97/stage2/builtins.c:1191: undefined reference to `__stack_chk_fail' pre_stage2_exec-builtins.o:/home/l4/Desktop/grub-0.97/stage2/builtins.c:1350: more undefined references to `__stack_chk_fail' follow collect2: ld returned 1 exit status make[2]: *** [pre_stage2.exec] Error 1 make[2]: Leaving directory `/home/l4/Desktop/grub-0.97/stage2' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/home/l4/Desktop/grub- 0.97' make: *** [all] Error 2 And the error when I patched the grub-0.97-os.1.diff is different. The error is below: builtins.c: In function 'vbeset_func': builtins.c :4891: warning: pointer targets in passing argument 1 of 'get_vbe_pmif' differ in signedness builtins.c:4891: warning: pointer targets in passing argument 2 of 'get_vbe_pmif' differ in signedness builtins.c: In function 'toggle_func': builtins.c:5463: error: invalid storage class for function 'process_var' builtins.c:5463: warning: no previous prototype for 'process_var' builtins.c:5523: error: invalid storage class for function 'process_block' builtins.c:5523: warning: no previous prototype for 'process_block' builtins.c: In function 'toggle_trigger_init': builtins.c:5744: error: invalid storage class for function 'detect_vmware' builtins.c:5744: warning: no previous prototype for 'detect_vmware' make[2]: *** [pre_stage2_exec- builtins.o] Error 1 make[2]: Leaving directory `/home/l4/grub-0.97/stage2' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/home/l4/grub-0.97' make: *** [all] Error 2 I compiled the grub under the ubuntu 7.04 environment, using the gcc-4.1.2and g++- 4.1.2.

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Capability based L4
by Luke A. Guest 08 Oct '07

08 Oct '07

Hi, I'm interested in seeing how capabilities work in a real OS kernel and was wondering if there is any source or documents available that I could read? Preferably not the Haskell stuff as I just don't get it :( Is there an implementation of L4.sec? The spec seems like it's missing stuff, is there an update anywhere? Thanks, Luke.

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Re: the problems of l4linux
by Adam Lackorzynski 08 Oct '07

08 Oct '07

On Wed Sep 19, 2007 at 09:01:38 +0000, chenggh wrote: > > Looks the same as the other mail. Enter helps? Actually, what do you > > expect to see? :) > Thanks. > I also read another mail with the same situation. I use Slackware 12.0 not > Ubuntu because in Ubuntu there is a glibc bug which has been existed at least > for more than half year - "undefined reference to __stack_chk_fail". This bug > has been reported many times and has committed to the Ubuntu Bug List. But > bug is as before. That's no bug, it's a stack protection feature they use. I didn't really care because I do not use Ubuntu myself but I think we have to work around this. > The first question: > the l4 boot log is like this: > l4lx | l4lx_thread_create: Created thread 10.16 (IRQ5) > l4lx | l4lx_irq_dev_startup_hw: Starting IRQ thread for IRQ 4. > l4lx | l4lx_thread_create: Created thread 10.17 (IRQ4) > l4lx | l4lx_irq_dev_startup_hw: Starting IRQ thread for IRQ 3. > l4lx | l4lx_irq_dev_startup_hw: Starting IRQ thread for IRQ 2. > l4lx | acquire_irq: Error attaching to IRQ 2 > l4lx | l4lx_thread_create: Created thread 10.19 (IRQ2) > l4lx | l4lx_irq_dev_startup_hw: Starting IRQ thread for IRQ 1. > l4lx | acquire_irq: Error attaching to IRQ 1 > It seems that when attaching IRQ1, IRQ2, IRQ9, IRQ12 there are some errors > like "acquire_irq: Error attaching to IRQ x". But later attaching IRQ is ok. > What is the matter? IRQ1 and IRQ12 are related with keyboard and monse, IRQ2 > is related with cascade, IRQ9 is about acpi. I have removed these drivers > from linux. why is it also like this? Think about who is supposed to have these IRQs. Keyboard and Mouse are already taken by the windowing/console system, so Linux can obviously not get them. So it is really ok that attaching those IRQs fail, it's supposed to be like this. > The second problem is: > The Linux booting stops at /ect/random-seed to initialize /dev/urandom and > there is no login interface. I have checked the normal linux booting and > after the using /ect/random-seed to initialize /dev/urandom the linux will > finish booting kernel, enter the linux user space "INIT: Entering init X". > So I think it is still the problem of l4linux kernel not the special linux > distribution. Is it right? Same question: Is your Slackware starting a login on tty1? What happens with normal Linux? You may want to disable your X for the test and check your /etc/inittab. Adam -- Adam adam(a)os.inf.tu-dresden.de Lackorzynski http://os.inf.tu-dresden.de/~adam/

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