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L4 Fiasco's scheduling in Multi-Core
by Ganis Zulfa Santoso 20 Mar '14

20 Mar '14

Hi l4-hackers, Suppose we have 2 cores (core 0 and core 1) and we have 2 tasks (task A and task B). And I assign all threads of task A to run in core 0 and all threads of task B to run in core 1. How L4 Fiasco's scheduler manages this? Will the tasks run together or they have to switch from one to another? >From what I understand, the tasks don't run together regardless which core they are located, is it correct? Thank you. Best regards, Ganis

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compiling L4RE for ARM
by Waldo 18 Mar '14

18 Mar '14

hello, i am a beginner in this topic, but you can tell me how i can compile L4re for ARM ?

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I was not able to run "Hello world" on my board(imx6).
by taeung 18 Mar '14

18 Mar '14

Hello, L4 hackers. I have questions about booting "Hello world" on myboard. Please help me. I'm try to boot "Hello world + L4re + fiasco" on my board of which name is 'freescale i.MX6 Quad SABRE SD'(Cortex-A9,ARMv7). I built L4re and Fiasco. So, i got L4 build tree and fiasco image. Although i have built uimage file by "make uimage" and and i try to "make qemu", i was not able to run "hello world". (For reference,i have run original linux of which name is Linux/ARM, OS Kernel ,Linux-3.0.35-2508-g54750ff on my board(Freescale imx6q_sabre_sd)) <1. Result of the try booting on my board after "make uimage"> ======================================================================== MMC read: dev # 2, block # 2048, count 8192 ... 8192 blocks read: OK ## Booting kernel from Legacy Image at 10800000 ... Image Name: L4 Image #3 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 1224704 Bytes = 1.2 MB Load Address: 11000000 Entry Point: 11000000 Verifying Checksum ... OK Loading Kernel Image ... OK OK Starting kernel ... ======================================================================== <1-1. My Question > Why stop at "Starting kernel..." ? Is wrong my environment variables in u-boot ? (If it is the problem, how fix u-boot environment variables from '1-4'? ) Or, my toolchains(linaro gcc 4.6 (64bit) ) are a wrong choice ? <1-2. Fiasco : What i configured for myboard > ======================================================================== Target configuration ---> Architecture (ARM processor family) Platform (Freescale i.MX) Freescale i.MX (i.MX6) CPU (ARM Cortex-A9 CPU) [ ] Enable alignment check (NEW) [ ]Execution Model (Standard mode) [ ] Enable the deprecated 'swp' instruction (NEW) [*] Enable L2 Cache [ ] Enable FPU co-processor [ ] Enable CPU errata workarounds (NEW) Kernel options ---> [*] Enable multi processor support (4) Maximal supported number of CPUs (NEW) [*] Fine-grained CPU time Scheduler (Fixed priority scheduler) ======================================================================== <1-3. L4 re : What i configured for myboard> ======================================================================== Target Architecture 3. ARM architecture (BUILD_ARCH_arm) (NEW) CPU variant 9. ARMv7A type CPU (CPU_ARM_ARMV7A) (NEW) Platform Selection 7. Freescale i.MX6 (PLATFORM_TYPE_imx6) (NEW) Automatically determine internal gcc preprocessor names (INT_CPP_NAME_SWITCH) [Y/n] (NEW) Y Automatically determine internal ld names (INT_LD_NAME_SWITCH) [Y/n] (NEW) Y Strip binaries on install (BID_STRIP_PROGS) [N/y/?] (NEW) N GCC: Omit Frame-pointers (BID_GCC_OMIT_FP) [N/y/?] (NEW) N Build doc directories (BID_BUILD_DOC) [N/y/?] (NEW) N Enable RELEASE flag (RELEASE_MODE) [N/y/?] (NEW) N ======================================================================== <1-4. U-boot : what i set environment variable for my board> (u-boot-mx6q-sabresd.bin is supported from freescale home page.) ======================================================================== MX6Q SABRESD U-Boot > setenv loadaddr 0x10800000 MX6Q SABRESD U-Boot > setenv bootargs_base 'setenv bootargs console=ttymxc0,115200' MX6Q SABRESD U-Boot > setenv bootargs_mmc 'setenv bootargs ${bootargs} root=/dev/mmcblk1p1 rootwait rw video=mxcfb1:dev=ldb,LDB-XGA,if=RGB666 video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24' MX6Q SABRESD U-Boot > setenv bootcmd_mmc 'run bootargs_base bootargs_mmc;mmc dev 2;mmc read ${loadaddr} 0x800 0x2000;bootm' MX6Q SABRESD U-Boot > setenv bootcmd 'run bootcmd_mmc' MX6Q SABRESD U-Boot > saveenv Saving Environment to MMC... Writing to MMC(2)... done MX6Q SABRESD U-Boot > run bootcmd ======================================================================== <2. Result of the second try "make qemu"> ======================================================================== root@taeung-MS-7798:/path/to/obj2/tudos# make qemu E=hello-cfg MODULE_SEARCH_PATH=/path/to/obj2/fiasco/ make[1]: Entering directory `/home/taeung/Hello_test_l4/src/l4' ... Generating bootstrap.ld Building entry "hello-cfg". Merging image /path/to/obj2/fiasco//fiasco to mod00 [360kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/sigma0 to mod01 [351kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/moe to mod02 [2365kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/l4re to mod03 [1228kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/ned to mod04 [2387kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/hello.cfg to mod05 [1kB] Merging image /path/to/obj2/tudos/bin/arm_armv7a/l4f/hello to mod06 [896kB] ... Compiling exec.o ... Compiling module.o ... Compiling ARCH-arm/crt0.o ... Compiling region.o ... Compiling startup.o ... Compiling init_kip_v2.o ... Compiling init_kip_v4.o ... Compiling libc_support+.o ... Compiling patch.o ... Compiling koptions.o ... Compiling platform/imx.o ... Compiling loader_mbi.o ... Compiling ARCH-arm/reboot.o ==> Linking bootstrap.elf ==> Post-processing bootstrap.elf ==> "bootstrap.elf" built ==> Installing bootstrap.elf in image directory ==> Installing bootstrap_hello-cfg in image directory ==> Installing bootstrap_hello-cfg.elf in image directory Image size(s) in bytes: bootstrap_hello-cfg.elf: 1257856 Start address: 0x11000000 --> Build-Nr: 4 ==> Installing bootstrap.elf to local build-tree ==> Installing bootstrap_hello-cfg to local build-tree ==> Installing bootstrap_hello-cfg.elf to local build-tree QEmu-cmd: qemu-system-arm -kernel /path/to/obj2/tudos/images/bootstrap.elf qemu: fatal: Trying to execute code outside RAM or ROM at 0x11000000 R00=00000000 R01=00000000 R02=00000000 R03=00000000 R04=00000000 R05=00000000 R06=00000000 R07=00000000 R08=00000000 R09=00000000 R10=00000000 R11=00000000 R12=00000000 R13=00000000 R14=00000000 R15=11000000 PSR=400001d3 -Z-- A svc32 s00=00000000 s01=00000000 d00=0000000000000000 s02=00000000 s03=00000000 d01=0000000000000000 s04=00000000 s05=00000000 d02=0000000000000000 s06=00000000 s07=00000000 d03=0000000000000000 s08=00000000 s09=00000000 d04=0000000000000000 s10=00000000 s11=00000000 d05=0000000000000000 s12=00000000 s13=00000000 d06=0000000000000000 s14=00000000 s15=00000000 d07=0000000000000000 s16=00000000 s17=00000000 d08=0000000000000000 s18=00000000 s19=00000000 d09=0000000000000000 s20=00000000 s21=00000000 d10=0000000000000000 s22=00000000 s23=00000000 d11=0000000000000000 s24=00000000 s25=00000000 d12=0000000000000000 s26=00000000 s27=00000000 d13=0000000000000000 s28=00000000 s29=00000000 d14=0000000000000000 s30=00000000 s31=00000000 d15=0000000000000000 FPSCR: 00000000 bash: line 3: 5158 Aborted (core dumped) $qemu -kernel /path/to/obj2/tudos/images/bootstrap.elf make[1]: *** [qemu] Error 134 make[1]: Leaving directory `/home/taeung/Hello_test_l4/src/l4' make: *** [qemu] Error 2 ======================================================================== <2-1. My Question > Qemu support cpu such as cortex-A9 and ARMv7. But it not support mahine information for Freescale i.MX6 quad sabre sd. Because this is the reason, Can't boot "Helloworld + L4re+Fiasco" by qemu ? Or Is there other reason ? Thank you, if you help whatever. /Regards, Taeung Song | Student of Computer Engineering Hansung University./

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In Freescale i.MX6q_sabre_sd,The problem booting Helloworld + L4 + Fiasco
by taeung 17 Mar '14

17 Mar '14

Hello, L4 hackers. I have one question. please help me.. I have failed booting 'L4 Linux + L4 + Fiasco' on my board(Freescale i.MX6 Quad SABRE SD : Cortex-A9 , ARMv7) So, i'm try to boot 'Helloword + L4 + Fiasco' on my board Such as.. |$ svn cathttp://svn.tudos.org/repos/oc/tudos/trunk/repomgr | perl - inithttp://svn.tudos.org/repos/oc/tudos fiasco l4re | 1. L4 Re : configure and build (Success) |||==========================================================================| $ mkdir -p /path/to/obj/tudos |$ make O=/path/to/obj/tudos oldconfig $ make O=/path/to/obj/tudos -j2| |========================================================================== | |2. Fiasco : configure and build (Success)| || |========================================================================== $ cd /somedir/tudos/src/kernel/fiasco $ make BUILDDIR=/path/to/obj/fiasco $ cd /path/to/obj/fiasco $ make menuconfig $ make ========================================================================== 3. But,when i try to 'make uimage' or 'make qemu', error is happened. such as.. ========================================================================== root@taeung-MS-7798:/path/to/obj2/tudos# make uimage E=hello-cfg MODULE_SEARCH_PATH=/path/to/obj2/fiasco/ make[1]: Entering directory `/home/taeung/Hello_test_l4/src/l4' =========== Updating RAM_BASE for platform imx6 to 0x10000000 ========= ... Regenerating RAM_BASE settings Library dependencies missing: libc_minimal cxx_util cxx_io cxx_base cxx_io_kdebug l4sys-direct l4sys in directory '/home/taeung/Hello_test_l4/src/l4/pkg/sigma0/server/src'; aborting. /home/taeung/Hello_test_l4/src/l4/mk/binary.inc:348: *** Cflags dependencies missing: libc_minimal cxx_util cxx_io cxx_base cxx_io_kdebug l4sys-direct l4sys in directory '/home/taeung/Hello_test_l4/src/l4/pkg/sigma0/server/src'; aborting.. Stop. make[2]: *** [/path/to/obj2/tudos/pkg/sigma0/server/src/OBJ-arm_armv7a-l4f] Error 2 make[1]: *** [check_and_adjust_ram_base] Error 2 ========================================================================== |<< My Question >> Although i search of '|Library dependencies missing: libc_minimal cxx_util cxx_io cxx_base cxx_io_kdebug l4sys-direct l4sys|' in google.com, i could'nt get information about this error. I don't know why the problem is happened updating |'RAM_BASE for platform imx6 to 0x10000000'. | || Please any help.. /Regards, Taeung Song | Student of Computer Engineering Hansung University./

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L4Linux + L4re + Fiasco to boot in Freescale i.MX6q_sabre_sd
by taeung 17 Mar '14

17 Mar '14

Hello L4 hackers. I have two question (My question 1, 2 ). please help me. I'm trying to boot 'L4Linux + L4re + Fiasco' in Freescale i.MX6 Quad SABRE SD board (Cortex-A8, ARMv7-A). Such as.. 0. Get Source and install required package. |$ cd /somedir/tudos $ svn cat http://svn.tudos.org/repos/oc/tudos/trunk/repomgr | perl - init http://svn.tudos.org/repos/oc/tudos fiasco l4re l4linux_requirements| 1. L4 Re : configure and build (Success) |||==========================================================================| $ mkdir -p /path/to/obj/tudos |$ make O=/path/to/obj/tudos oldconfig $ make O=/path/to/obj/tudos -j2| |==========================================================================| 2. Fiasco : configure and build (Success) |==========================================================================| ||$ cd /somedir/tudos/src/kernel/fiasco |$ make BUILDDIR=/path/to/obj/fiasco $ cd /path/to/obj/fiasco $ make menuconfig $ make| |==========================================================================| 3. L4 linux : configure and build. (Failure) (Here, i have trouble to build l4 linux after configure according to my board ) |==========================================================================| |$ cd /somedir/tudos $ svn co http://svn.tudos.org/repos/oc/l4linux/trunk l4linux $ cd l4linux $ mkdir /path/to/obj/l4linux $ make L4ARCH=arm CROSS_COMPILE=arm-linux- O=/path/to/obj/l4linux arm_defconfig # In the menu, in "L4Linux configuration", set "L4 tree build directory" to /path/to/obj/tudos $ make L4ARCH=arm CROSS_COMPILE=arm-linux- O=/path/to/obj/l4linux menuconfig ||==========================================================================| To configure according to my board(Freescale i.MX6q_sabre_sd), I was able to choice two kinds. <The first > |System type -> ARM system type (L4 Linux) Build type (Use ARMv7) | <Result of the first > 1) Sucess build L4 linux and i got 'vmlinuz.arm' 2) 'make uImage' according to module.list |========================================================================== entry L4Linux_xs_2 kernel fiasco -nokdb roottask moe rom/l4linux.cfg module l4linux.cfg module l4re module ned module vmlinuz.arm module ramdisk-arm.rd| |==========================================================================| 3) i make SD Card bootable by u-boot.bin and bootstrap.uImage 4) Booting L4Linux + L4re + Fiasco in Freescale i.MX6q_sabre_sd But, i have problem to boot it. =========================================================================== U-Boot 2009.08 (Aug 16 2013 - 12:04:20) CPU: Freescale i.MX6 family TO1.2 at 792 MHz Thermal sensor with ratio = 180 Temperature: 44 C, calibration data 0x5764ba7d mx6q pll1: 792MHz mx6q pll2: 528MHz mx6q pll3: 480MHz mx6q pll8: 50MHz ipg clock : 66000000Hz ipg per clock : 66000000Hz uart clock : 80000000Hz cspi clock : 60000000Hz ahb clock : 132000000Hz axi clock : 264000000Hz emi_slow clock: 132000000Hz ddr clock : 528000000Hz usdhc1 clock : 198000000Hz usdhc2 clock : 198000000Hz usdhc3 clock : 198000000Hz usdhc4 clock : 198000000Hz nfc clock : 24000000Hz Board: i.MX6Q-SABRESD: unknown-board Board: 0x63012 [POR ] Boot Device: SD I2C: ready DRAM: 1 GB MMC: FSL_USDHC: 0,FSL_USDHC: 1,FSL_USDHC: 2,FSL_USDHC: 3 In: serial Out: serial Err: serial i2c: I2C3 SDA is low, start i2c recovery... I2C3 Recovery success Found PFUZE100! deviceid=10,revid=11 Net: got MAC address from IIM: 00:04:9f:02:70:b5 FEC0 [PRIME] Hit any key to stop autoboot: 0 mmc2 is current device MMC read: dev # 2, block # 2048, count 17408 ... 17408 blocks read: OK ## Booting kernel from Legacy Image at 10800000 ... Image Name: L4 Image #7 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 7680000 Bytes = 7.3 MB Load Address: 11000000 Entry Point: 11000000 Verifying Checksum ... OK Loading Kernel Image ... OK OK Starting kernel ... ========================================= <My question 1.> Why hang at 'Starting kernel ...' ? Setting environment variable and bootcmd , i have thought the setting is no problem. This kernel image is wrong? <The Second > |System type ---> ARM system type (Allow multiple platforms to be selected)| Multiple platform selection ---> ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait) Build type Freescale i.MX family Freescale i.MX support ---> i.MX6 Quad/DualLite support <Result of the second > i could not build l4 linux because.. GEN /path/to/obj/l4linux/Makefile scripts/kconfig/conf --silentoldconfig Kconfig ERROR: CONFIG_ARM_PATCH_PHYS_VIRT must not be enabled. make[1]: *** [check_linux_config] Error 1 make: *** [sub-make] Error 2 <My question 2.> Why can not build L4 linux according to this config ? and What is CONFIG_ARM_PATCH_PHYS_VIRT ? Please any help.. /Regards, Taeung Song | Student of Computer Engineering Hansung University. /

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Re: Problem in Linking program
by Irvanda Kurniadi 13 Mar '14

13 Mar '14

Case closed. I found that the __assert_fail is not supported in uclibc. Then, I tried to change __assert_fail with __assert and it works. But I'm still curious about using glibc in L4re. I try to compile my program using libgcc but it also doesn't work. Can it cause any problem if I use glibc compiler than any of requires_libs using uclibc compiler? just wondering irvanda

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Problem in Linking program
by Irvanda Kurniadi 12 Mar '14

12 Mar '14

Hi, I'm trying to build my program in L4/Fiasco. This program requires libtiff, MPI, and libstep library. I've ported those all libraries. But, when I built my program, I got a problem in linking program. The compilation just work fine but when entering the linking part, I got this error message: ==> Linking sobel-step ........ main-sobel-V4.cpp_processed.o: In function `main': /home/l4re-mpich/src/l4/pkg/sobel-step/server/src/main-sobel-V4.cpp_processed.c:57: undefined reference to `__assert_fail' /home/l4re-mpich/src/l4/pkg/sobel-step/server/src/main-sobel-V4.cpp_processed.c:56: undefined reference to `__assert_fail' ......... This "__assert_fail" should be available in libstep.so and I've put the LDFLAGS = -lstep on my makefile. Here is my Makefiel anyway: PKGDIR ?= ../.. L4DIR ?= $(PKGDIR)/../.. SYSTEMS = x86-l4f amd64-l4f include $(L4DIR)/mk/Makeconf ifneq ($(SYSTEM),) # check whether used gcc has the omp.h file available OMP_H_PATH := $(shell $(CC) -print-file-name=include/omp.h) ifeq ($(strip $(OMP_H_PATH)),include/omp.h) $(info [32m $(CC) does not have omp.h header file available, skipping.[0m) else TARGET = $(if $(filter 4.2 4.3 4.4 4.5 4.6 4.7,$(GCCVERSION)),sobel-step) REQUIRES_LIBS = libgomp libtiff libmpich libmpich_f77sup libstep libc libc_support_misc endif endif SRC_C = main-sobel-V4.cpp_processed.c sobel-omp-V4.cpp_processed.c pictureInterface.c util.c CFLAGS += -fopenmp -I. -g -Wall LDFLAGS += -rpath -ltiff -rpath -lstep PRIVATE_INCDIR = $(SRC_DIR) vpath %.c $(SRC_DIR) include $(L4DIR)/mk/prog.mk Previously I compiled the program and there are so much missing shared libraries and the debug message suggested to add the -rpath. I updated my LDFLAGS by adding the -rpath. Here is the error message before I add the LDFLAGS with -rpath: ==> Linking sobel-step .... ld: warning: libl4z.so, needed by /home/l4re-mpich/obj/l4/x86/lib/x86_586/l4f/libtiff.so, not found (try using -rpath or -rpath-link) ld: warning: libgfortran.so, needed by /home/l4re-mpich/obj/l4/x86/lib/x86_586/l4f/libstep.so, not found (try using -rpath or -rpath-link) ....... ld: final link failed: Bad value I'm not sure whether this is causing another problem by adding the -rpath. I mean, Is it the proper way to fix the missing shared library? Because the "__asser_fail" is supposed to be found in the libstep.so but I still got the undefined reference error message. So perhaps there are several things to wrap up this linking problem. If you by any chance find any misplace or missing configuration in my makefile or you have any idea how to fix it please let me know. Thanks Regards, Irvanda

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seL4 what exactly is in the kernel
by Taylor Bioniks 11 Mar '14

11 Mar '14

Like all L4 kernels, it provides basic mechanisms which must be in the kernel for security reasons. These include low-level interrupt and exception handlers (which essentially convert these events into IPC messages to user-level handlers), a notion of address spaces into which you can map frames (basically an abstraction of page tables), a notion of kernel-scheduled (and context-switched) threads, a notion of a protection domain (capability tree) and a communication and synchronisation mechanism (IPC endpoints). Other L4 kernels have similar abstractions. Please explain what you mean by notion? Do you mean that it has code to deal with the user mode memory management and such? What is different in seL4 is that all memory management is done at user level. After booting up and allocating and initialising its static data structures (scheduling queues, the kernel stack and a few globals) the kernel sets up an initial user address space with a single thread, and hands it the rights to all remaining memory (in the form of "Untyped" capabilities). When performing an operation that requires kernel data structures (eg creating a thread requires creating a thread control block, TCB) the user has to provide these, by "retyping" some Untyped memory into a kernel object type. This makes it kernel memory (inaccessible to userland), but the owner of that memory can always revoke it (revert it to Untuped, thus nuking the kernel object). so is the single kernel stack in it's own address space or is it somehow mapped or shared with other address spaces? There's a single kernel stack, which is in use whenever kernel code executes. The terms "kernel mode" or "user mode" make no sense for data - they refer to the processor mode that is active when particular code is executing. However, the kernel stack is, of course, a kernel object, only accessible in kernel mode. While the kernel stack (like the scheduler queues) is somewhat special, in that it is allocated by the kernel at boot time, in terms of accessibility it's no different from other "kernel objects", such as PTs or TCBs, that are allocated by userland. so kernel objects are stored in this user mode kernel stack? Okay, so the kernel never actually has a stack in kernel mode, and it never allocates space for itself does this mean that the kernel does not grow? And if so does that eliminate the requirement that I've seen on X86 machines where they have 1GB for the kernel and 3GB for the user programs Final thing is I've been pointed to the university site a few times and I've been told there are slides with audio on there, however, I can never find them even after mirroring the site and looking through it. Where might I find these?

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Problem when booting L4 Fiasco/Re
by Sören Jonsson 10 Mar '14

10 Mar '14

Hello, I have now successfully compiled the L4 Fiasco.OC and your runtime environment. I made the hello.iso bootable image as well, and made an attempt to run it under VMWare workstation. My problem is that it don't work. It stops during boot, with the following information: I had to provide two images, in order to capture all information. The information above "Total RAM: 255MB" disapers very fast otherwise. Is this enough information to explain what is happening, or can I provide more information using other methods? With my best regards, Sören Jonsson Sweden

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seL4 what exactly is in the kernel
by Taylor Bioniks 08 Mar '14

08 Mar '14

What does the seL4 kernel actually provide in the kernel itself? I've read through documentation and it seems they just stop before they state exactly what the seL4 kernel does. So what I'd like to know is what features and components are in the kernel and what is outside of it? Does the kernel have a single kernel stack or multiple kernel stacks and is/are it/they in kernel mode or user mode? Are there any good diagrams that show how seL4 works with its user space components? Thanks in advance

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