l4-hackers September 2018

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

14 participants
8 discussions

Filesystem Architectures with L4Re and L4-Based Systems
by Paul Boddie 02 Dec '19

02 Dec '19

Hello, As this list can attest, I previously spent a bit of time diving into the way dynamic linking is supported by L4Re to get shared mode programs working. This turned out to have a relatively simple fix related to symbols employed by GCC- generated code. But during this exercise, I gained some familiarity with the way libraries are loaded, and this appears to involve the virtual filesystem support, with the loader perusing the filesystem to access libraries, and with these being provided as modules by the "rom" filesystem. Since then, I've spent some time looking at how files are provided by filesystems and accessed by code that uses the conventional C or POSIX library interfaces. It raises a few questions about why things are done in a particular way in L4Re, and which approaches are in use for other L4-based systems, especially those that seek to provide general-purpose, multi-user solutions. What I think I now understand about the virtual filesystem support in L4Re is as follows. The virtual filesystem itself is a "client-side" construct, meaning that it resides within any given program. That programs have their own view of a filesystem is not too different from what the documentation about systems like the Hurd describes and advocates, and I suppose it is a tempting approach because it gives each program the flexibility to be customised in this regard. However, it seems that beyond the internal "mount tree" representation, configuration of the namespace hierarchy is largely done using the L4Re namespace concept, with namespaces acting as directories, and non-namespace objects within the hierarchy interpreted as particular file types. Apart from the interpretation of namespaces as directories, it seems that for the most part, dataspaces are employed to be interpreted as file objects. I will admit that I didn't really look very hard at how different systems provide file access before now, but what surprised me slightly was the apparent lack of delegation in L4Re. As far as I can tell, on systems based on kernels like Linux, the open library function will employ a system call to delegate the matter of finding the file and obtaining a way of accessing it to the familiar monolithic-kernel-plus-filesystems arrangement. On more "exotic" systems (than Linux) like Minix 3 or the Hurd, it appears that delegation to a virtual filesystem server [1] or servers [2] occurs to mediate access to specific files. Some systems like Inferno and Plan 9 employ protocols [3] to formalise the client-server relationship. I had almost expected to find similar things in L4Re, but I could only confirm their absence after reviewing the various VFS abstractions. One thing I wonder about is whether the current L4Re approach is able to satisfactorily deal with filesystem content that needs to serve different user entities, with content having different permission and ownership rights. It seems that the filesystem logic has to be available as a library within a program, which is not necessarily a problem. But to avoid filesystem content being completely exposed to the discretion of user programs (reminiscent of the problems with early Network File System implementations), the library would need to call out to other entities, which doesn't appear to be done with the current L4Re abstractions. One could implement support for, say, the ext3 filesystem in a library, operating on a dataspace provided at some kind of mountpoint in a directory (with the directory being provided by a namespace, of course) but it would be like giving a user program access to a block device in a traditional Unix-like system. Are there any articles about the design of L4Re that might explain the motivations here? And are there any accessible-but-detailed articles about other microkernel-based systems and the way in which they structure their filesystem architectures? I looked around on the TU-Dresden site for materials, but I didn't immediately find anything obviously relevant. Paul [1] https://wiki.minix3.org/doku.php?id=developersguide:vfsinternals [2] https://www.gnu.org/software/hurd/hurd-talk.html#pat [3] http://doc.cat-v.org/inferno/4th_edition/styx

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Information on implementing L4
by John 05 Oct '18

05 Oct '18

Hi all. I've been looking at Google and Wikipedia for information about L4, and it's fairly thin. I've come up with that L4 has read and write registers and performs IPC by fixed-length registers, with all actions synchronous (I guess that means you send a message and block until the target thread reads the message). Is there a more concrete document anywhere about implementing an L4 microkernel and what makes it L4? I'm surveying the field at the moment and looking at all the advances made in computer software—security, managed language runtimes, hypervisors, real-time OS—and trying to project the possibilities for a next-generation operating system. There's enough divergence that a rewrite from scratch might make sense; and besides, I've drawn up a method for getting a self-hosting CLR running with only anonymous memory allocation and VFS file page mapping, along with a method of getting the CLR to self-host and getting it up and running before an actual OS kernel. In other words: it's readily-achievable to write a CLR in C#, get it running on itself before the kernel comes up, then load a kernel, VMM, VFS, ABI, scheduler, and so forth—all written in C#, compiled to CIL, and totally independent of the hardware architecture underneath—and then throw away the loader and bring up init. The kernel would need to use an abstract factory model to do common tasks which require hardware-specific code, and the CLR would need to load an assembly with a concrete factory for the particular hardware and a few built-in native assembly calls; but it's doable. This is all theoretical at the moment, and I want to explore the particular edges a little to see what I find out.

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Call from 8-bytes aligned stack to functions that require 16-bytes stack alignment
by Yuxuan Shui 25 Sep '18

25 Sep '18

Hi, L4Linux is compiled with -mpreferred-stack-boundary=3, but the "external functions" it calls are usually compiled without this option, so defaults to 16 bytes alignment. This causes potential unaligned memory access if the compiler choose to generate instructions like movdqa. QEMU without kvm seems to just let this pass, but with kvm enabled, this could generate a GP. -- Regards Yuxuan Shui

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RE: Issues about server multi-threading on L4Re
by 李鼎基 21 Sep '18

21 Sep '18

Oh yes! Actually I used the version without arguments. Now I think I can try to fix this problem with the constructor with arguments. Thank you very much! From: Jakub Jermar<mailto:jakub.jermar@kernkonzept.com> Sent: Friday, September 21, 2018 23:12 To: 李鼎基<mailto:lidingji1997@hotmail.com> Subject: Re: Issues about server multi-threading on L4Re On 09/21/2018 05:02 PM, 李鼎基 wrote: > Actually, I’ve tried to run the server loop in only one thread (a new > thread created by “pthread_create”, NOT the main thread) on server. > > Theoretically, it should perform the same as running the server loop in > the main thread, but the server still gets stuck. How did you create your Object_registry / Registry_server - there is a version for the main thread which has constructor without arguments [0] and uses the main thread - and then there is a version with a constructor that takes arguments [1], among which is a server thread. You need to use the second version to tell it about your new thread. Can it be that you are using the version without arguments? [0] https://l4re.org/doc/classL4Re_1_1Util_1_1Registry__server.html#a694a009623… [1] https://l4re.org/doc/classL4Re_1_1Util_1_1Registry__server.html#ad88c4355e6… HTH, Jakub > > ------------------------------------------------------------------------ > *发件人:* l4-hackers <l4-hackers-bounces(a)os.inf.tu-dresden.de> 代表 > Jakub Jermar <jakub.jermar(a)kernkonzept.com> > *发送时间:* Friday, September 21, 2018 10:26:12 PM > *收件人:* l4-hackers(a)os.inf.tu-dresden.de > *主题:* Re: Issues about server multi-threading on L4Re > > Hi there! > > On 09/21/2018 02:10 PM, 李鼎基 wrote: >> I’m trying to implement some multi-threading IPC benchmarks on L4Re. >> Following the /“shared_ds”**/demo, firstly, I create 8 threads to send >> IPC on client and receive them all on server’s main thread. >> >> The server loops, waits for the requests and handles them in the >> “dispatch” function. This single-thread server works well. >> >> >> >> Then I want to create 8 threads in server (so that it can serve the >> client thread-to-thread). >> >> I wrap the “server.loop();” in a “thread_fn” and use “pthread_create” to >> create more threads, however, the server will get stuck. >> >> There are some printings after entering thread_fn so that I can make >> sure new threads are created and executed except the server.loop part. > > I guess the problem is in that you are trying to use the same server > loop for all your threads. The server loop is associated with a single > server thread that executes the server objects. In other words, all but > the thread which is associated with your server loop just block there > and don't receive any IPC calls. > >> In order to serve different requests concurrently, is there any way to >> create a multi-threading server? > > In theory (never tried that myself), you can try giving a separate > server loop to each of your threads. You will then need to register your > server object at each of them. The end result should be that your client > threads are each connected to a different IPC gate which has its own > bound server thread. All of these gates carry the label of the same > server object which will be invoked when an IPC call arrives at any of them. > > HTH, > Jakub > > -- > Kernkonzept GmbH at Dresden, Germany, HRB 31129, CEO Dr.-Ing. Michael > Hohmuth > > _______________________________________________ > l4-hackers mailing list > l4-hackers(a)os.inf.tu-dresden.de > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers -- Kernkonzept GmbH at Dresden, Germany, HRB 31129, CEO Dr.-Ing. Michael Hohmuth

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Issues about server multi-threading on L4Re
by 李鼎基 21 Sep '18

21 Sep '18

Hi, I’m trying to implement some multi-threading IPC benchmarks on L4Re. Following the “shared_ds” demo, firstly, I create 8 threads to send IPC on client and receive them all on server’s main thread. The server loops, waits for the requests and handles them in the “dispatch” function. This single-thread server works well. Then I want to create 8 threads in server (so that it can serve the client thread-to-thread). I wrap the “server.loop();” in a “thread_fn” and use “pthread_create” to create more threads, however, the server will get stuck. There are some printings after entering thread_fn so that I can make sure new threads are created and executed except the server.loop part. In order to serve different requests concurrently, is there any way to create a multi-threading server? -- Thanks

2 1

High 32 bits of SFMASK is reserved
by Yuxuan Shui 20 Sep '18

20 Sep '18

Hi, In cpu-64.cpp, in function Cpu::setup_sysenter, Fiasco try to set IA32_FMASK (called MSR_SFMASK in the code) to ~0ULL. However, only the lower 32bit of FMASK should be written to. This cause problems on some platforms. -- Regards Yuxuan Shui

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cost (cycles + cache) of setup and use of IPC mechanisms
by Zenaan Harkness 17 Sep '18

17 Sep '18

Establishing any IPC communication channel has setup costs and per message or per "message batch" usage costs: (CPU cycles + context switches) / channel setup (CPU cycles + context switches) / msg[-batch] Further, as recent Linux kernel network stack work has discovered, cache effects strongly proscribe batch processing rather than per-msg (or per packet) processing (seems obvious, I guess "in hindsight") to make 10G and above network links work well: Batch processing of network packets https://lwn.net/Articles/763056/ and see also: User-space networking with Snabb https://lwn.net/Articles/713918/ Is there a paper quantifying and comparing various IPC mechanism costs? Specifically and separately, is there a paper quantifying the setup and use costs of shared memory IPC (possibly in comparison with any other IPC mechanism)? TIA,

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L4linux booting problem on IMX.6 based board
by diming.zhang＠gmail.com 04 Sep '18

04 Sep '18

Hi, I'm working on building L4linux for my imx.6 arm-board. But the booting stopped before the l4linux console coming out. The logs is as follows: U-Boot 2015.04-imx_v2015.04_3.14.52_1.1.0_ga+g6cf684a (Sep 01 2018 - 05:09:24) CPU: Freescale i.MX6Q rev1.5 at 792 MHz CPU: Temperature 33 C Reset cause: POR Board: MX6-SabreSD I2C: ready DRAM: 1 GiB MMC: FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2 *** Warning - bad CRC, using default environment No panel detected: default to Hannstar-XGA Display: Hannstar-XGA (1024x768) In: serial Out: serial Err: serial switch to partitions #0, OK mmc2(part 0) is current device Net: FEC [PRIME] Error: FEC address not set. Normal Boot Hit any key to stop autoboot: 1 0 reading l4linux.uimage 10982764 bytes read in 291 ms (36 MiB/s) ## Booting kernel from Legacy Image at 11000000 ... Image Name: L4 Image #51 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 10982700 Bytes = 10.5 MiB Load Address: 11000000 Entry Point: 11000000 Verifying Checksum ... OK Loading Kernel Image ... OK Starting kernel ... L4 Bootstrapper Build: #51 Mon Sep 3 02:20:50 CST 2018, 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701] Scanning up to 1024 MB RAM, starting at offset 32MB Memory size is 1024MB (10000000 - 4fffffff) RAM: 0000000010000000 - 000000004fffffff: 1048576kB Total RAM: 1024MB Scanning fiasco Scanning sigma0 Scanning moe Moving up to 12 modules behind 11100000 moving module 02 { 11a45000-11a7952b } -> { 11b36000-11b6a52b } [214316] moving module 01 { 11a3a000-11a443b7 } -> { 11b2b000-11b353b7 } [41912] moving module 00 { 1197f000-11a399d7 } -> { 11a70000-11b2a9d7 } [764376] moving module 11 { 1167f000-1197efff } -> { 11770000-11a6ffff } [3145728] moving module 10 { 11673000-1167e766 } -> { 11764000-1176f766 } [46951] moving module 09 { 1124b000-116724cf } -> { 1133c000-117634cf } [4355280] moving module 08 { 1124a000-1124a0ee } -> { 1133b000-1133b0ee } [239] moving module 07 { 11248000-1124992f } -> { 11339000-1133a92f } [6448] moving module 06 { 11247000-112473b3 } -> { 11338000-113383b3 } [948] moving module 05 { 11087000-11246a87 } -> { 11178000-11337a87 } [1833608] moving module 04 { 11025000-1108676b } -> { 11116000-1117776b } [399212] moving module 03 { 1100f000-110244ef } -> { 11100000-111154ef } [87280] Loading fiasco Loading sigma0 Loading moe find kernel info page... found kernel info page (via ELF) at 10002000 Regions of list 'regions' [ 10000000, 100001bf] { 1c0} Root mbi_rt [ 10001000, 10001a3f] { a40} Kern fiasco [ 10002000, 100cbfff] { ca000} Kern fiasco [ 10100000, 10109c5f] { 9c60} Sigma0 sigma0 [ 10119fcc, 1011e177] { 41ac} Sigma0 sigma0 [ 10140000, 10173d0b] { 33d0c} Root moe [ 10183f70, 1018f4b3] { b544} Root moe [ 11000000, 1100e5bb] { e5bc} Boot bootstrap [ 11100000, 11a6ffff] { 970000} Root Module found kernel options (via ELF) at 10003000 Sigma0 config ip:101003f4 sp:00000000 Roottask config ip:10141590 sp:00000000 Starting kernel fiasco at 10001230 Hello from Startup::stage2 Number of IRQs available at this GIC: 160 FPU: Initialize FPU0: Subarch: 3, Part: 30, Rev: 4, Var: 9, Impl: 41 L2: ID=410000c7 Type=9e340340 Aux=32070000 WMask=ffff S=0 L2: Type L2C-310 Size = 1024kB Ways=16 Waysize=64 SERIAL ESC: allocated IRQ 61 for serial uart Not using serial hack in slow timer handler. Welcome to L4/Fiasco.OC! L4/Fiasco.OC microkernel on arm Rev: unknown compiled with gcc 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701] for i.MX6 [] Build: #1 Sat Sep 1 02:19:56 CST 2018 Calibrating timer loop... done. MDB: use page size: 20 MDB: use page size: 12 SIGMA0: Hello! KIP @ 10002000 allocated 4KB for maintenance structures SIGMA0: Dump of all resource maps RAM:------------------------ [4:10000000;10000fff] [0:100cc000;100fffff] [0:1010a000;10118fff] [0:1011f000;1013ffff] [4:10140000;10173fff] [0:10174000;10182fff] [4:10183000;1018ffff] [0:10190000;110fffff] [4:11100000;11a6ffff] [0:11a70000;4effffff] IOMEM:---------------------- [0FPU1: Subarch: 3, Part: 30, Rev: 4, Var: 9, Impl: 41 :Cache config: ON 0ID_PFR[01]: 00001231 00000011; ID_[DA]FR0: 00010444 00000000 fID_MMFR[04]: 00100103 20000000 01230000 00102111 ffffff] [0:50000000;ffffffff] MOE: Hello world MOE: found 1021396 KByte free memory MOE: found RAM from 10000000 to 4f000000 MOE: allocated 1008 KByte for the page array @0x10190000 MOE: virtual user address space [0-bfffffff] MOE: rom name space cap -> [C:103000] MOE: rwfs name space cap -> [C:105000] BOOTFS: [11100000-111154fFPU2: Subarch: 3, Part: 30, Rev: 4, Var: 9, Impl: 41 0Cache config: ON ]ID_PFR[01]: 00001231 00000011 ID_[DA]FR0: 00010444 00000000 [ID_MMFR[04]: 00100103 20000000 01230000 00102111 C:107000] l4re BOOTFS: [11116000-1117776c] [C:109000] ned BOOTFS: [11178000-11337a88] [C:10b000] io BOOTFS: [11338000-113383b4] [C:10d000] l4lx_imx6.cfg BOOTFS: [11339000-1133a930] [C:10f000] imx6_hw_devices.devs BOOTFS: [1133b000-1133b0ef] [C:111000] l4lx-imx6.io BOOTFS: [1133c000-117634d0] [C:113000] vmlinuz BOOTFS: [11764000-1176f767] [C:115000] imx6FPU3: Subarch: 3, Part: 30, Rev: 4, Var: 9, Impl: 41 qCache config: ON _ID_PFR[01]: 00001231 00000011s ID_[DA]FR0: 00010444 00000000 aID_MMFR[04]: 00100103 20000000 01230000 00102111 bresd.dtb BOOTFS: [11770000-11a70000] [C:117000] ramdisk-arm.rd MOE: cmdline: moe rom/l4lx_imx6.cfg MOE: Starting: rom/ned rom/l4lx_imx6.cfg MOE: loading 'rom/ned' Ned says: Hi World! Ned: loading file: 'rom/l4lx_imx6.cfg' l4linux-IO| Io service l4linux-IO| Verboseness level: 4 l4linux-IO| unused physical memory space: l4linux-IO| [00000000000000-0000000fffffff] l4linux-IO| [00000050000000-000000ffffffff] l4linux-IO| no 'iommu' capability found, using CPU-phys for DMA l4linux-IO| Loading: config 'rom/imx6_hw_devices.devs' l4linux-IO| warning: inconsistent fixed resource @ device: /System Bus/ l4linux-IO| : hid= l4linux-IO| compatible= { "fsl,imx6q-fec" } l4linux-IO| DMADOM [00000000000000-00000000000000 1] non-pref (32bit) (align=0 flags=6) l4linux-IO| Loading: config 'rom/l4lx-imx6.io' l4linux-IO| Real Hardware ----------------------------------- l4linux-IO| System Bus: hid= l4linux-IO| Resources: ==== start ==== l4linux-IO| DMADOM [00000000000000-00000000000000 1] non-pref (32bit) (align=0 flags=6) l4linux-IO| Resources: ===== end ===== l4linux-IO| ethernet: hid= l4linux-IO| compatible= { "fsl,imx6q-fec" } l4linux-IO| Clients: ===== start ==== l4linux-IO| ethernet: [N2Vi9Proxy_devE] l4linux-IO| Clients: ===== end ==== l4linux-IO| Resources: ==== start ==== l4linux-IO| IOMEM [00000002188000-0000000218bfff 4000] non-pref (32bit) (align=3fff flags=2) l4linux-IO| IRQ [00000000000096-00000000000096 1] level high (32bit) (align=0 flags=300001) l4linux-IO| IRQ [00000000000097-00000000000097 1] level high (32bit) (align=0 flags=300001) l4linux-IO| DMADOM [00000000000000-00000000000000 1] non-pref (32bit) (align=0 flags=6) l4linux-IO| Resources: ===== end ===== l4linux-IO| warning: could not register control interface at cap 'platform_ctl' l4linux-IO| Ready. Waiting for request. l4linux | PH 0 offs=00010000 flags=rwx PH-type=0x1 l4linux | virt=03000000 evirt=0348e000 l4linux | phys=03000000 ephys=0348e000 l4linux | f_sz=004071fc memsz=0048e000 l4linux | PH 1 offs=003c099c flags=r-- PH-type=0x4 l4linux | virt=033b099c evirt=033b09c0 l4linux | phys=033b099c ephys=033b09c0 l4linux | f_sz=00000024 memsz=00000024 l4linux | PH 2 offs=00000000 flags=rwx PH-type=0x6474e551 l4linux | virt=00000000 evirt=00000000 l4linux | phys=00000000 ephys=00000000 l4linux | f_sz=00000000 memsz=00000000 l4linux | Starting binary at 0x3000260, argc=5 argv=0xafff4f94 *argv=0xb1007ff4 argv0=rom/vmlinuz l4linux | External resolver is at 0xa8000b48 l4linux | ======> L4Linux starting... <======== l4linux | Linux version 4.17.0-l4 (zhangdiming@ubuntu) (gcc version 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701] (Linaro GCC 7.3-2018.05)) #7 Mon Sep 3 02:20:06 CST 2018 l4linux | Binary name: rom/vmlinuz l4linux | This is an AEABI build. l4linux | Linux kernel command line (4 args): mem=64M console=ttyLv0l4x_rd=rom/ramdisk-arm.rd root=1:0 ramdisk_size=4000 l4linux | CPU mapping (l:p)[1]: 0:0 l4linux | Image: 03000000 - 03600000 [6144 KiB]. l4linux | Areas: Text: 03000000 - 032f5000 [3028kB] l4linux | RO-Data: 032f5000 - 0339b000 [664kB] l4linux | Data: 033d6000 - 034071fc [196kB] l4linux | Init: 033b1000 - 033d6000 [148kB] l4linux | BSS: 034071fc - 0348e000 [539kB] l4linux | Device scan: l4linux | Device: L4ICU l4linux | Device: ethernet l4linux | MEM: 02188000 - 0218bfff l4linux | IRQ: 00000096 - 00000096 l4linux | IRQ: 00000097 - 00000097 l4linux | DMAD: 00000000 - 00000000 l4linux | Device scan done. l4linux | l4lx_thread_create: Created thread 41d (cpu0) (u:b3000e00, v:b3000c00, sp:033d7fa4) l4linux | main thread will be 41d l4linux | L4x: section-with-init(-data): Virt: 0x3000000 to 0x348dfff [4664 KiB] l4linux | section-with-init(-data): Phys: 0x10719fff00000000 to 0x123800000000, [8 KiB] l4linux | L4x: section-with-init-text: Virt: 0x3000000 to 0x348dfff [4664 KiB] l4linux | error: failed to get physical address for 3000000. l4linux | L4x: data: Virt: 0x3000000 to 0x348dfff [4664 KiB] l4linux | error: failed to get physical address for 3000000. l4linux | L4x: Main thread running, waiting... l4linux | L4x: Memory size: 64MB l4linux | L4x: Setting superpages for main memory l4linux | L4x: Adjusted memory start: 03000000 l4linux | L4x: Main memory: Virt: 0x3600000 to 0x75fffff [65536 KiB] l4linux | Main memory: Phys: 0x11c00000 to 0x15bfffff, [65536 KiB] l4linux | L4x: vmalloc area: 07600000 - 0f600000 l4linux | L4x: text: Virt: 0x3000000 to 0x348dfff [4664 KiB] l4linux | error: failed to get physical address for 3000000. l4linux | Loading: rom/ramdisk-arm.rd l4linux | INITRD: Size of RAMdisk is 3072KiB l4linux | RAMdisk from 00002000 to 00302000 [3072KiB] l4linux | l4lx_thread_create: Created thread 422 (timer0) (u:b3000a00, v:00000000, sp:0342ffa0) l4linux | Booting Linux on physical CPU 0x0 l4linux | Linux version 4.17.0-l4 (zhangdiming@ubuntu) (gcc version 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701] (Linaro GCC 7.3-2018.05)) #7 Mon Sep 3 02:20:06 CST 2018 l4linux | CPU: Fiasco [412fc09a] revision 10 (ARMv7), cr=00400000 l4linux | CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache l4linux | Machine: L4 l4linux | Ignoring unrecognised tag 0x00000000 l4linux | Memory policy: Data cache writealloc l4linux | CPU: All CPU(s) started in SVC mode. l4linux | INITRD: 00002000 - 00302000 l4linux | random: get_random_bytes called from start_kernel+0x9c/0x3c0 with crng_init=0 l4linux | Built 1 zonelists, mobility grouping on. Total pages: 17685 l4linux | Kernel command line: mem=64M console=ttyLv0l4x_rd=rom/ramdisk-arm.rd root=1:0 ramdisk_size=4000 l4linux | Dentry cache hash table entries: 16384 (order: 4, 65536 bytes) l4linux | Inode-cache hash table entries: 8192 (order: 3, 32768 bytes) l4linux | Memory: 64776K/71684K available (3028K kernel code, 196K rwdata, 664K rodata, 148K init, 539K bss, 6908K reserved, 0K cma-reserved) l4linux | Virtual kernel memory layout: l4linux | vector : 0xffff0000 - 0xffff1000 ( 4 kB) l4linux | fixmap : 0xffc00000 - 0xfff00000 (3072 kB) l4linux | vmalloc : 0x07600000 - 0x0f600000 ( 128 MB) l4linux | lowmem : 0x00000000 - 0x07600000 ( 118 MB) l4linux | modules : 0x02010000 - 0x03000000 ( 15 MB) l4linux | .text : 0x(ptrval) - 0x(ptrval) (3028 kB) l4linux | .init : 0x(ptrval) - 0x(ptrval) ( 148 kB) l4linux | .data : 0x(ptrval) - 0x(ptrval) ( 197 kB) l4linux | .bss : 0x(ptrval) - 0x(ptrval) ( 540 kB) l4linux | NR_IRQS: 282 l4linux | clocksource: l4kipclk: mask: 0xffffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 3526361616960 ns l4linux | l4timer: Using IRQ210 l4linux | sched_clock: 64 bits at 1000kHz, resolution 1000ns, wraps every 2199023255500ns l4linux | Console: colour dummy device 80x30 l4linux | console [ttyLv0] enabled l4linux | Calibrating delay loop... 1581.05 BogoMIPS (lpj=7905280) l4linux | pid_max: default: 32768 minimum: 301 l4linux | Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) l4linux | Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) l4linux | CPU: Testing write buffer coherency: ok l4linux | Setting up static identity map for 0x3000000 - 0x3000000 l4linux | VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4 l4linux | clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns l4linux | futex hash table entries: 256 (order: -1, 3072 bytes) l4linux | NET: Registered protocol family 16 l4linux | DMA: preallocated 256 KiB pool for atomic coherent allocations l4linux | Failed to create "l4x" debugfs directory: -19 l4linux | clocksource: Switched to clocksource l4kipclk l4linux | NET: Registered protocol family 2 l4linux | tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes) l4linux | TCP established hash table entries: 1024 (order: 0, 4096 bytes) l4linux | TCP bind hash table entries: 1024 (order: 0, 4096 bytes) l4linux | TCP: Hash tables configured (established 1024 bind 1024) l4linux | UDP hash table entries: 256 (order: 0, 4096 bytes) l4linux | UDP-Lite hash table entries: 256 (order: 0, 4096 bytes) l4linux | NET: Registered protocol family 1 l4linux | Trying to unpack rootfs image as initramfs... l4linux | rootfs image is not initramfs (junk in compressed archive); looks like an initrd l4linux | INITRD: Freeing memory. l4linux | l4x: Checks passed. l4linux | NetWinder Floating Point Emulator V0.97 (double precision) l4linux | workingset: timestamp_bits=30 max_order=14 bucket_order=0 l4linux | io scheduler noop registered l4linux | io scheduler deadline registered l4linux | io scheduler cfq registered (default) l4linux | io scheduler mq-deadline registered l4linux | io scheduler kyber registered l4linux | L4 serial driver l4linux | serial-ttyLv.0: ttyLv0 at MMIO 0x1 (irq = 0, base_baud = 230400) is a L4-vcon l4linux | l4ser_shm: L4 shared mem serial driver l4linux | l4cdds: No name given, not starting. l4linux | brd: module loaded l4linux | l4bdds: No name given, not starting. l4linux | NET: Registered protocol family 17 l4linux | RAMDISK: ext2 filesystem found at block 0 l4linux | RAMDISK: Loading 3072KiB [1 disk] into ram disk... | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ done. l4linux | EXT4-fs (ram0): mounting ext2 file system using the ext4 subsystem l4linux | EXT4-fs (ram0): mounted filesystem without journal. Opts: (null) l4linux | VFS: Mounted root (ext2 filesystem) readonly on device 1:0. l4linux | Freeing unused kernel memory: 148K l4linux | This architecture does not have kernel memory protection. l4linux | The booting stopped at here, and there is no sentance as "Please press Enter to activate this console." displayed. ============================== module.list ------------------------------------- modaddr 0x01100000 default-kernel fiasco -serial_esc default-bootstrap bootstrap entry imx6-arm roottask moe rom/l4lx_imx6.cfg module l4re module ned module io module l4lx_imx6.cfg module imx6_hw_devices.devs module l4lx-imx6.io module vmlinuz module[perl] "ramdisk-$ENV{ARCH}.rd" ============================== At this point I have no idea what to do any help will be much appreciated! Thank you very much! Regards Jason

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l4-hackers September 2018