l4-hackers May 2013

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

12 participants
11 discussions

Error during the "ned" package build (svn revision 42)
by ggasnier31＠free.fr 16 Jul '13

16 Jul '13

Hello, I got the following error building the "ned" package for ARM architecture (Cortex-A9, Pandaboard). I use the last Linaro toolchain "gcc-linaro-arm-linux-gnueabihf-4.7-2012.12-20121214_linux". === Building package "ned" === make[1]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned' make[2]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server' make[3]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src' ... Building /home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/.general.d make[3]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src' make[3]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src' make[4]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f' ... Building .general.d ... Building Makefile.inc make[4]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f' make[4]: Entering directory `/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f' make[4]: *** No rule to make target `ned.lua.bin.o', needed by `ned'. Stop. make[4]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f' make[3]: *** [/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f] Error 2 make[3]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src' make[2]: *** [src] Error 2 make[2]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server' make[1]: *** [server] Error 2 make[1]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned' make: *** [ned] Error 2 Commenting the line "OBJS += ned.lua.bin.o" in the file l4/pkg/ned/server/src/Makefile gives this error. ==> Linking ned lua.o: In function `lua(int, char const* const*)': /home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src/lua.cc:97: undefined reference to `_binary_ned_lua_start' /home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src/lua.cc:97: undefined reference to `_binary_ned_lua_end' make[4]: *** [ned] Error 1 make[4]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f' make[3]: *** [/home/repository/L4.kernel/fiasco/src/l4/ArmBuild/pkg/ned/server/src/OBJ-arm_armv7a-l4f] Error 2 make[3]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server/src' make[2]: *** [src] Error 2 make[2]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned/server' make[1]: *** [server] Error 2 make[1]: Leaving directory `/home/repository/L4.kernel/fiasco/src/l4/pkg/ned' make: *** [ned] Error 2 Regards, Guillaume GASNIER

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Kernel debugger in MP mode causes double fault
by Markus Partheymueller 01 Jun '13

01 Jun '13

Hi folks, has anyone tried to invoke the kernel debugger in a multiprocessor setup? When I boot the demo scenario in qemu with qemu -smp 2 -cpu core2duo and then hit Escape, the system crashes with a double fault. Without smp or with -cpu qemu32 the problem doesn't occur. Can someone confirm this issue or give a hint what could be wrong? Cheers Markus

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L4Re: FATAL: Exception Operation not permitted: ''"
by Maximin Coste 01 Jun '13

01 Jun '13

Hi, I'm running an edited and "old" (September 2012) version of L4Linux & uC-OS/II in top of Fiasco+L4RE (updated here). When launching the image I have generated, I have the following error: MOE: cmdline: moe rom/l4lx_ucos.cfg MOE: Starting: rom/ned rom/l4lx_ucos.cfg MOE: loading 'rom/ned' Ned says: Hi World! Ned: loading file: 'rom/l4lx_ucos.cfg' Ucos | L4Re: FATAL: Exception Operation not permitted: '' Ucos | Exception: Operation not permitted: : backtrace ... l4linux | L4Re: FATAL: Exception Operation not permitted: '' l4linux | Exception: Operation not permitted: : backtrace ... io | Dev_factory: register factory for N2Hw6DeviceE io | GTF: register factory for 7Pci_dev io | GTF: register factory for N2Hw12Msi_resourceE io | Dev_factory: register factory for N2Hw11Gpio_deviceE io | Io service io | Ready. Waiting for request. Can I see more about what's going wrong ? Can I see the backtrace those logs talks about ? :) -- Maximin COSTE-LEENHARDT

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How to boot Fiasco microkernel on raspberry pi
by Rahul Singhal 31 May '13

31 May '13

I want to port Fiasco microkernel to RPi. I found that Fiasco now supports RPi. I am a newbie in this kernel field. I have compiled the L4 microkernel and the L4 runtime environment for RPi succesfully but I don't know how to use the generated binaries to run RPi. I am running on ubuntu 12.04. Could you please tell me the procedure and files to be put on the sd card of RPi so that it boots into the L4 runtime environment.

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sigma0 memory space
by joel＠nider.org 31 May '13

31 May '13

I have been reading about the structure of L4Ka::Pistachio, and discovered that they use idempotent (1:1) page table mapping in their sigma0 process. I am wondering if Fiasco also takes this approach? If so, does the kernel also use idempotent mapping? I would imagine that this would have some implications on demand paging in the kernel. Does the kernel even use demand paging? (I mean at some point during boot the kernel will start to use memory to store kernel objects - either the kernel 'guesses' how much it will ever need and statically allocates that memory, or it's going to have to ask for pages later on, which will be owned by some other process). I tried to read the code, but found it very hard to traverse - the C++ classes don't make it easy to follow a flow. Can you please point out the file(s) where the kernel sets up the memory space for sigma0, and where it passes the initial ownership (from kernel space to sigma0 space)? Thanks, Joel

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Building l4re packages and linking errors
by Bryce Cronkite-Ratcliff 13 May '13

13 May '13

Hi folks, I'm afraid my configuration may have changed recently, possibly due to version changes in gcc, and I'm having some trouble compiling l4re, so I wanted to ping you to see if you had any insights. Two separate issues I've had: in an existing l4re build, executing make in an individual package sub-directory fails to find basic system headers in included files ("stddef.h" and "stdarg.h" for example). I'm running make O=basel4rebuilddir On the theory that l4re needs to be recompiled in order to set up links that may have changed since compilation of the last build, I've tried building l4re again, but I similarly run into a linker problem here: gcc: symbol lookup error: /home/bryce/L4Linux/x86/l4re4/tool/gendep/64/libgendep.so: undefined symbol: dlsym If you have any thoughts on what I might try, let me know! Thank you! Bryce

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Questions about Fiasco.OC and L4Re
by BogDan 13 May '13

13 May '13

Hello, First I'd like to introduce myself, I'm BogDan Vatra a free software hacker. Recently I've watched these http://wiki.tudos.org/HOWTOs#Introduction_to_Fiasco.OC_and_L4Re presentations on youtube. After I've seen them (many many times) I became fascinated. I started to "play" a little bit with Fiasco.OC and L4Re, I created a few apps and I must confess that I'm extremely impressed by your work. To me Fiasco.OC and L4Re seems way too good to be true, and I wonder if there are any "hidden traps" which prevents people to use it to create a general-purpose operating system on top of Fiasco.OC and L4Re, so my first question is: Can Fiasco.OC and L4Re be used to create free (GPL, BSD, apache, etc.) and non-free apps? I checked L4Re licenses and it seems that it has the necessary exceptions, but I'd like to be 100% sure :). I also look to Genode frameowrk and I it looks to me that it cannot be used to create non-GPL apps, so, it can not be used to create a general-purpose operating system where any kind of apps can run on it. I also have a few questions about the completeness of Fiasco.OC and L4Re: - does L4Re have any OpenGL support? I checked the source code and it seems that the only way to do graphics is via goos and it doesn't seem to have any OpenGL support. If I am right wouldn't be easier to port (and upstream) an existing server (e.g. xorg, wayland, mir, etc.) to L4Re, than to create one from scratch and maintain it? - does L4Re have any sound support? If it hasn't, then how hard will be to implement or to port an existing implementation? - does L4Re have any real filesystem support (e.g. ext2/3/4, xfs, raiser, etc.)? It is ok for testing to use qemu or grub to load simple apps, but for a real o.s., apps need to be loaded from disk. Again, if it hasn't, then how hard will to implement it or to port an existing implementation? - it is possible to use a debugger (e.g gdb(server)) to debug (user space) apps? - last but not least, is there any repository for Fiasco.OC and L4Re with logs? http://svn.tudos.org/repos/oc/tudos/trunk/ has no useful logs and IMHO it makes very hard any contribution to it. I've seen that you have a few repos on github (https://github.com/TUD-OS), do you have any plans to move Fiasco.OC and L4Re to github as well? IMHO being able to fork a repository and to create a pull request, to be able to open an issue and watch its progress will make contributors life much more easier :) ! Many thanks for your work! Yours, BogDan.

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Question regarding the "Jdb::handle_user_request()' function
by Christian Prochaska 11 May '13

11 May '13

Hello, the 'Jdb::enter_jdb()' function in file 'jdb.cpp' contains the following code: // check for int $3 user debugging interface if (foreach_cpu(&handle_user_request, true)) { close_debug_console(cpu); leave_trap_handler(cpu); return 0; } I'm not sure why in this case the second argument of 'foreach_cpu()' is true. I understand that it causes the result to be true only if the 'handle_user_request()' function returned true for every currently running CPU. But I found that this can be a problem when using the '-jdb_cmd=JS' kernel argument: if only one CPU is currently running, the result of 'foreach_cpu()' is true, but when two CPUs are currently running, the 'handle_user_request()' function returns true only for one CPU, which makes the end result false and causes the kernel to stop with the JDB prompt shown. Can somebody please explain? Christian

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fiasco r52 on beagleboard xm
by Sin-ta Hsiea 11 May '13

11 May '13

Hi, I've tried running r47 fiasco kernel on beagleboard xm platform, it was fine, but after upgrading sources to r52, it broke. Output message hang after this line. Hello from Startup::stage2 After debugged using JTAG, I found that after page table modified, MMU still can't translate that address. So I add this line to source: --- src/kern/arm/paging-arm.cpp (revision 52) +++ src/kern/arm/paging-arm.cpp (working copy) @@ -348,6 +348,7 @@ void Pte_ptr::write_back_if(bool, Mword asid = Mem_unit::Asid_invalid) { + Mem_unit::clean_dcache(pte); if (asid != Mem_unit::Asid_invalid) Mem_unit::tlb_flush(asid); } Then output message hang after this line: Calibrating timer loop... done. It seems that MMU doesn't notice page table was switched to sigma0's pagetable. I also tried pandaboard, it just works fine. Does anybody have idea how to fix this? Best regard, SIn-ta Hsiea

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Fiasco.OC with ARM TrustZone
by Chao-Jui Chang 11 May '13

11 May '13

Hi hackers, Is trustzone working on exynos 4412 platform? I have selected the follow item in Fiasco config menu: * Platform Timer (Multi-core timer) * Use ExtGic * Execution Model (TrustZone normal side) But it stop at early stage. Same result for Execution Model (Standard mode). but no message for Execution Model (TrustZone secure side). If the trustzone is disabled in u-boot, the 'Standard mode' works fine. ----- booting log ----- OK U-Boot 2010.12-00000-g8d816e8-dirty (May 06 2013 - 19:38:10) for Exynox4412 CPU: S5PC220 [Samsung SOC on SMP Platform Base on ARM CortexA9] APLL = 1000MHz, MPLL = 880MHz DRAM: 1023 MiB PMIC VERSION : 0x00, CHIP REV : 3 TrustZone Enabled BSP BL1 version: 20121128 Checking Boot Mode ... SDMMC MMC Device 0: 30959 MB MMC Device 1 not found ModeKey Check... run normal_boot Net: No ethernet found. Hit any key to stop autoboot: 0 Exynos4412 # run fiasco Partition2: Start Address(0x2000), Size(0x1a000) reading bootstrap.raw 835584 bytes read Boot with zImage Starting kernel ... Hello from Startup::stage2 Per_cpu_data_alloc: (orig: 0xf0044588-0xf0044f60) Number of IRQs available at this GIC: 160 ------ end of booting log ----- Best regards, Chao-Jui

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l4-hackers May 2013