l4-hackers July 2009

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

11 participants
10 discussions

Back to UTCB IPC
by Marc CHALAND 11 Oct '09

11 Oct '09

Hi, I am back with my problem with UTCB IPC. To sum up the context : I use pure l4env applications. Here is the scenario between my server and my client : 1. client makes an UTCB IPC to manager. Manager does an l4rm_area_reserve, creates a rcv_fpage, creates worker and sends back worker thread id to client. 2. client allocates memory and associated flexpage and sends it to server. 3. UTCB IPC is sent to worker with 3 parameters : - on client side : utcb->values=0xbff00200: arg1=0x2 arg2=0x1 arg3=0x6 - on server side : utcb->values=0xbff00200: arg1=0x241401 arg2=0x0 arg3=0x7069776c It seems that 0xbff00200 is not mapped on the same memory on client and server side. As there is no problem for first IPC (utcb->values is also 0xbff00200), is there any potential problem with flexpage ? As utcb->values is still the same, what happens if several threads try to make UTCB IPC ? Another question : when I link my application with liblogserver.a, I have strange logs : .rm.sem.mainMain function returned. It seems that .rm .sem and .main are added by l4env, but I didn't find where. Regards Marc

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Howto implement a periodic real-time task?
by Andre Puschmann 10 Aug '09

10 Aug '09

Hey guys, I got a L4 real-time application that should run strictly periodic. In each cycle I have to communicate with at least two other L4 threads in different address spaces. The cycle period is in the order of 1000Hz to 5000Hz. As described in [1] I tried to use the CPU reservation server but the sample implementations did not work. Anyway, I figured out that even the CPU reservation server depends on the kernel timer and thus the granularity is 1ms (in PIT mode), which is too coarse for cycle periods larger then 1000Hz. Although I like the idea to use OS primitives to keep the application as portable as possible (ARM port is a goal), I thought about implementing the periodic execution with an extra timer decoupled from the scheduling timer which generates an IRQ at each hit. Any comment/suggestions/ideas about that? Any other experience with periodic real-time tasks on L4? Cheers, Andre [1] http://os.inf.tu-dresden.de/pipermail/l4-hackers/2009/004179.html

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compiling Fiasco trunk, Bison trouble
by Roman Beslik 04 Aug '09

04 Aug '09

Hello. I'm trying to compile Fiasco trunk using this manual: http://os.inf.tu-dresden.de/fiasco/use.html . When I compile tudos/l4 tree, many errors appear in tudos/dice/src/parser/idl : {{{ g++ -DHAVE_CONFIG_H -I. -I. -I../../.. -I../../../src -Wall -I../../../src -g -O2 -MT idl-scanner.o -MD -MP -MF .deps/idl-scanner.Tpo -c -o idl-scanner.o idl-scanner.cc In file included from ../../../src/parser/idl/location.hh:44, from idl-parser.tab.hh:65, from idl-parser-driver.hh:35, from idl-scanner.ll:6: position.hh: In function ‘bool yy::operator==(const yy::position&, const yy::position&)’: position.hh:136: warning: suggest parentheses around ‘&&’ within ‘||’ In file included from idl-parser-driver.hh:35, from idl-scanner.ll:6: idl-parser.yy: At global scope: idl-parser.yy:76: error: use of enum ‘EXPT_OPERATOR’ without previous declaration idl-parser.yy:78: error: ISO C++ forbids declaration of ‘CFETypeSpec’ with no type idl-parser.yy:78: error: expected ‘;’ before ‘*’ token idl-parser.yy:79: error: ISO C++ forbids declaration of ‘CFEAttribute’ with no type idl-parser.yy:79: error: expected ‘;’ before ‘*’ token idl-parser.yy:80: error: ISO C++ forbids declaration of ‘CFEExpression’ with no type idl-parser.yy:80: error: expected ‘;’ before ‘*’ token {{{many errors skipped}}} make[6]: *** [idl-scanner.o] Error 1 make[6]: Leaving directory `/tudos/dice/src/parser/idl' }}} It seems that tudos/dice/src/fe/*.h files is not included with "#include" in tudos/dice/src/parser/idl/idl-parser.tab.hh, because when I include them by hand, "g++ ..." works out without an error. >yacc --version bison (GNU Bison) 2.4.1 >g++ --version g++ (GCC) 4.4.0 20090630 (prerelease) >ls -l /usr/local/bin/byacc lrwxrwxrwx 1 root root 13 2009-07-14 04:24 /usr/local/bin/byacc -> /usr/bin/yacc -- Best regards, Roman Beslik.

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problems running l4linux
by Stefan Kögel 31 Jul '09

31 Jul '09

Hi, i am trying to run l4linux on top of fiasco. Using the cfg start script from the website to load vmlinux. But after that nothing really happens and the keyboard somehow gets redirected to my serial connection. jdb output is: loader | sleeping for 1000 ms loader | vmlinux: Starting sigma0-style application loader | vmlinux: Loading binary loader | vmlinux,#f: Entry at 00009c3c => 00400000 loader | vmlinux,#f: Started loader | DEBUG file = vmlinux loader | vmlinux,#f: Double PF (r) at 00000000 eip 00000000 (F.00) It seems to load quite ok, but nothing else. But I may have not payed enough attention to configuring the l4linux kernel. I know I tryed to turn off any serial drivers. Which part should have control over the keyboard? Thank you for your help. Kind Regards, Stefan

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problem with l4linux
by fang zhengshu 27 Jul '09

27 Jul '09

hi, I'm sorry to trouble you,but I have a question with X server when start l4linux on dope. I have search a mail which you have sent: > Yes, I know that this setup is not easy. For overlay_wm driver to work it is necessary to apply patches to X Server sources, as I read. But I thought it must work with linux server with ordinary l4con/dope frambuffer driver. So, it won't, ok. -- When I checked on real machine (not with ramdisk), l4linux started and XServer starts OK. > I can start l4linux on dope and con,and also on serial console.The below is what I use in l4linux.cfg: task "vmlinuz" "earlyprintk=yes mem=64M video=l4fb root=/dev/hda9 " all_sects_writable allow_vga allow_cli could you please tell me what I missing? thank you. -- fang,

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the dde_linux26 link error
by Guanghui, Cheng 27 Jul '09

27 Jul '09

Hello: i write a device driver for L4 with DDE but when i compile the server and client code it can't link into the lib dde_linux26 with the error like this: ld: cannot find -ldde_linux26 I check the files in the libdde* and there are only these files: libddekit.a libdde_linux26_block.a libdde_linux26_net.a libdde_linux26.o.a libdde_linux26_sound.a No libdde_linux26.a but libdde_linux26.o.a instead. Maybe some configuation is wrong and thanks for your any suggestion. Cheng

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Call for Papers: Embedded Software Track at DATE 2010
by André Hergenhan 25 Jul '09

25 Jul '09

Hello, I would like to invite you to submit your research contributions and advanced (industrial) applications to the Embedded Software Track at DATE 2010. With this respect, I would especially like to refer to topic E4, which may be of particular interest to the L4 community. Best regards, André. Call for Papers Embedded Software Track at DATE 2010 Dresden, Germany March 8-12, 2010 The Design, Automation and Test in Europe conference and exhibition is the main European event bringing together design automation researchers, users and vendors, as well as specialists in the design, test, and manufacturing of electronic systems and circuits. It puts strong emphasis on embedded systems, including embedded software which has become a main track of DATE. The DATE conference is a five-day event consisting of plenary keynotes, regular papers, interactive presentations, panels and hot-topic sessions, tutorials, master courses and workshops. The DATE conference and the exhibition, together with the many user group meetings, fringe meetings, university booth and social events offer a wide variety of opportunities to meet and to exchange information. Embedded Topic Areas: E1 Real-time, Networked, and Dependable Systems Chairs: Petru Eles, Linkoping University, Sweden; Luís Almeida, Universidade do Porto, Portugal Real-time programming languages and software; formal models for real-time systems; software performance analysis; worst case execution time analysis; scheduling and software estimation; real-time system optimization; verification; tools and design methods; adaptive real-time systems; dependable systems; software for safety critical systems; software for sensor networks and networked applications; network control and QoS for embedded applications. E2 Compilers and Code Generation for Embedded Systems Chairs: Shuvra Bhattacharyya, University of Maryland, USA; Rainer Leupers, RWTH Aachen,, Germany Software-centric system design exploration; software synthesis; compilers; code generation (e.g. C from matlab); dynamic compilation for embedded systems; software tool chain; generation for design space exploration (compilers, simulators, synthesis tools); retargetable compilers for MPSOC and reconfigurable platforms; compilers for multi-core systems. E3 Model-based Design for Embedded Systems Chairs: Albert Benveniste, IRISA, France; Christoph Kirsch, University of Salzburg, Austria Model-based foundations, methods, and tools for principled embedded/control system/software design; model-based embedded/control system/software testing, verification, validation, integration, deployment; model-based system and software architectures and infrastructure for principled embedded/control software deployment. E4 Embedded Software Architectures and Principles Chairs: Ahmed Jerraya, Leti, France; André Hergenhan, OpenSynergy, Germany Software for MPSoC and multi-core systems; virtualization for embedded systems, including safety and security aspects; resources constrained middleware and Run-Time Environment (RTE) architectures, e.g., AUTOSAR; software support for reconfigurable components and accelerators. E5 Embedded Software Applications - Architectures, Tools, and Methodologies Chairs: Wolfgang Ecker, Infineon Technologies, Germany; Werner Damm, OFFIS, Germany Real-time and dependable software applications; embedded run-time environments - practice and applications; embedded software verification and certification; design processes and experience in dependable software design; model driven design in industrial practice; embedded software architectures and applications in aerospace, automotive, industrial, medical industries; embedded software in wireless and consumer electronics applications; sensor network applications. Submission Instructions: All manuscripts must be submitted electronically before September 6th, 2009, following the instructions on the conference Web page: http://www.date-conference.com The accepted file format is PDF Manuscripts received in hard-copy form will not be processed. Papers can be submitted for either standard oral presentation or for interactive presentation. Standard oral presentations require novel and complete research work supported by experimental results, and are held in front of a full audience. Besides these, DATE will again include interactive presentations of novel ideas that may require additional research or lack experimental data. Interactive presentations are given on a laptop in a face-to-face discussion area. Submissions should not exceed 6 pages in length for oral-presentation and 4 pages in length for interactive-presentation papers, and should be formatted as close as possible to the final format: A4 or letter sheets, double column, single spaced, Times or equivalent font of minimum 10pt (templates are available on the DATE Web site for your convenience). To permit blind review, submissions should not include the author names. Any submission not in line with the above rules will be discarded. All papers will be evaluated with regard to their suitability for the conference, originality and technical soundness. The Programme Committee reserves the right to accept interesting contributions that do not meet the criteria for standard oral presentations, as interactive presentations. Information: Rolf Ernst - DATE Embedded Software Track Chair IDA Technische Universität Braunschweig Hans-Sommer-Str. 66 38106 Braunschweig, Germany e-mail: r.ernst(a)tu-bs.de Wolfgang Mueller - DATE Program Chair Paderborn University C-LAB, Fuerstenallee 11 33098 Paderborn, Germany e-mail: wolfgang(a)acm.org

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the drops-x.rd
by fang zhengshu 24 Jul '09

24 Jul '09

hi, I use the following command to mount the drops-x.rd in the l4lx26-nitpicker-xorg71.iso: sudo mount -t ramfs -o loop drops-x.rd /mnt but when I change into the /mnt, I find nothing. so someone can tell me how to mount the drops-x.rd or tell me something about the file drops-x.rd ? -- fang,

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read string from server array error!
by fang zhengshu 15 Jul '09

15 Jul '09

2009/7/8 fang zhengshu <fangzhsh07(a)gmail.com> > > > 2009/7/6 fang zhengshu <fangzhsh07(a)gmail.com> > >> hi all, >> when I write a function in the IDL file, there is a problem:want to write >> a different-length string to a array and then read parts of the array to >> another string like: >> >> interface test{ >> int write([string]char* str, int len); >> int read([out,prealloc_client, size_is(size), prealloc_server]char >> str[], int size); >> }; >> > I modify the idl file as the following: int write([in,string]char *str, int len) int read([out, prealloc_client]char *str, int len) there no error when compile it,but > >> I have defined a fixed size array in the server like array[256]. >> In the write() function I write a different length string to the array, >> then I want to read parts or all of the array in the read() function, the >> process will be like the following: >> >> string[len] str[size] >> | ^ >> | | >> --------->array[256] -----------| >> >> >> but when I put the function above and compile it, there are some error >> happen. I have change the size_is() with length_is() or max_is(), but there >> still error when I compile it. I know if I define a fix array str[256] the >> code can be work, but I just want to use a unfixed length array to get the >> string. >> could someone please give me some advice?if I describe the problem >> clearly, please let me know. >> >> thank you! >> >> I don't know whether I describe what I want to do clearly,so I put the > simple code below: > > read-client > write-client > #define STR_TO 30 > #define STR_FROM 30 > ... > ... > char str_to[SRR_TO]; > char str_from[STR_FROM]; > ... > ... > read(str_to, STR_TO); > write(str_from, STR_FROM); > ... > ... > > server > #define SIZE 256 > ... > char string[SIZE]; > ... > int write(char > *str_from, int str_from) > { > //write str_from size chars of str_from array to the > string array which is in server > } > int read(char *str_to, > int str_to) > { > //read str_to size chars from the string array which is in > server to str_to > } > > Then I define write functions as the above in a .idl file,but when I > compile it,there will be the following error: > terminate called after throwing an instance of 'std::out_of_range' > what(): CBEMsgBuffer::IsEarlier > make[1]: *** [test-server.c] Aborted > make[1]: *** [test-server.c] Deleting file `test-sys.h' > make[1]: *** [test-server.c] Deleting file `test-client.h' > make[1]: *** [test-server.c] Deleting file `test-client.c' > make: *** [/home/l4/tudos/build/pkg/ > fifo/idl/OBJ-x86-l4v2] Error 2 > > must we use the format as the dice manual below?: > int read([out, prealloc_client, size_is(len)] char **str, [out,in]int *len) > and when I modify the function as > int read([out, prealloc_client, prealloc_server, size_is(len)] char *str, > [out,in]int *len) > there is no error when compile it,but there will be another error called > :fpage > could you give me some advice for the read function? > thank you. > -- > fang, > when I run the test in qemu, the error come out: fifo | L4RM: [PF] read at 0x00002000, ip 01800aa1, src B.02 fifo | [B.0] l4rm/lib/src/pagefault.c:81:__unknown_pf(): fifo | unhandled page fault the execute code of fifo binary is : ... /home/l4/tudos/build/pkg/fifo/idl/OBJ-x86-l4v2/fifo-server.c:259 l4_msgdope_t _dice_size_dope; l4_msgdope_t _dice_send_dope; l4_umword_t _word[2]; } _word; } fifo_fifo_read_msg_buffer_t; l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0; 1800a8b: 85 db test %ebx,%ebx 1800a8d: 0f 84 f9 00 00 00 je 1800b8c <fifo_dispatch+0x21c> 1800a93: 80 3b 00 cmpb $0x0,(%ebx) 1800a96: 0f 84 11 01 00 00 je 1800bad <fifo_dispatch+0x23d> 1800a9c: 31 c0 xor %eax,%eax 1800a9e: 66 90 xchg %ax,%ax 1800aa0: 40 inc %eax 1800aa1: 80 3c 18 00 cmpb $0x0,(%eax,%ebx,1) 1800aa5: 75 f9 jne 1800aa0 <fifo_dispatch+0x130> 1800aa7: 8d 58 01 lea 0x1(%eax),%ebx ... the fifo-server.c:259 code is: inline void fifo_read_marshal (CORBA_Object _dice_corba_obj, int _dice_return /* out */, l4_msgtag_t *_dice_tag, char* str /* out */, fifo_msg_buffer_t *_dice_msg_buffer, CORBA_Server_Environment *_dice_corba_env) { ... l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0; ... so anyone can give me some advice? thank you! -- fang,

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Re: l4-hackers Digest, Vol 72, Issue 8
by fang zhengshu 08 Jul '09

08 Jul '09

hi all, when I write a function in the IDL file, there is a problem:want to write a different-length string to a array like: interface test{ int write([string]char* str, int len); int read([out,prealloc_client, size_is(size), prealloc_server]char str[], int size); }; I have defined a fixed size array in the server like array[256]. In the write() function I write a different length string to the array, then I want to read parts or all of the array in the read() function, the process will be like the following: string[len] str[size] | ^ | | --------->array[256] -----------| but when I put the function above and compile it, there are some error happen. I have change the size_is() with length_is() or max_is(), but there still error when I compile it. I know if I define a fix array str[256] the code can be work, but I just want to use a unfixed length array to get the string. could someone please give me some advice?if I describe the problem clearly, please let me know. thank you! -- fang,

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l4-hackers July 2009