September 2013 - l4-hackers - example.com Site

NOVA, NUL, snapshotting
by Sartakov A. Vasily 13 Jan '14

13 Jan '14

Hello. Does the NOVA/NUL support snapshotting of VMes? -- Sartakov A. Vasily

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L4Re::Util::Dataspace_svr
by Daniel Müller 01 Oct '13

01 Oct '13

Hello, L4Re::Util::Dataspace_svr's copy functionality is not very flexible. It only works for local dataspaces which I believe is insufficient. The problem is the "if (!src_cap.id_received())" construct in the L4Re::Dataspace_::Copy case in the dispatch method. Imo this should be something comparable to the validate_ds() method used in region_mapping_svr. Daniel

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ARMV7 virtualization extensions support
by Karoline Haus 01 Oct '13

01 Oct '13

Good afternoon, I'd like to understand if the Fiasco kernel already supports ARM's virtualization extensions (like it supports VT-x and AMD-V), and if not, is that something you are working on? Many thanks for any pointers. Karoline

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error in bootstrap when building amd64
by Joel Nider 01 Oct '13

01 Oct '13

Hi, I'm having trouble building the amd64 L4Re image. I'm building on Ubuntu 12.04 64-bit (kernel 3.2.0-29); make 3.81; gcc 4.6.3 (default) I'm using l4re-core-2013091917 (not the snapshot) that I got from here: http://os.inf.tu-dresden.de/download/snapshots-oc/l4re-core-2013091917.tar.… Everything builds fine until the 'bootstrap' package: === Building package "bootstrap" === make[1]: Entering directory `/home/joel/projects/l4re-core-2013091917/src/l4/pkg/bootstrap' make[2]: Entering directory `/home/joel/projects/l4re-core-2013091917/src/l4/pkg/bootstrap/server' make[3]: Entering directory `/home/joel/projects/l4re-core-2013091917/src/l4/pkg/bootstrap/server/src' make[4]: Entering directory `/home/joel/projects/l4re-core-2013091917/obj/l4/amd64/pkg/bootstrap/server/src/OBJ-amd64_K8' make[5]: Entering directory `/home/joel/projects/l4re-core-2013091917/src/l4/pkg/bootstrap/server/src/ARCH-amd64/libc32' make[6]: Entering directory `/home/joel/projects/l4re-core-2013091917/obj/l4/amd64/pkg/bootstrap/server/src/ARCH-amd64/libc32/OBJ-amd64_K8' make[6]: Leaving directory `/home/joel/projects/l4re-core-2013091917/obj/l4/amd64/pkg/bootstrap/server/src/ARCH-amd64/libc32/OBJ-amd64_K8' make[5]: Leaving directory `/home/joel/projects/l4re-core-2013091917/src/l4/pkg/bootstrap/server/src/ARCH-amd64/libc32' ==> Linking bootstrap32.elf /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.6/libgcc.a when searching for -lgcc /usr/bin/ld: cannot find -lgcc collect2: ld returned 1 exit status make[4]: *** [bootstrap32.elf] Error 1 Any ideas how to fix it? Thanks, Joel

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About the use of C++11 features
by Johannes Schlatow 20 Sep '13

20 Sep '13

Hi, I just noticed that the current snapshot (2013-08-19) doesn't compile with gcc4.4 anymore, which is apparently due to some C++11 incompatibilities (see below). Based on the snapshot from April, I got the Fiasco.OC and L4Re port for the LEON3 (sparc) up and running and would like to merge this with the newest snapshot. Unfortunately, the LEON3 cross compiler (bcc) is based on gcc4.4. So...what's your policy about supporting oldish cross-compilers? And, by the way, how do you feel about including the LEON3 code in your repository? Cheers Johannes Here is the condensed output of a gcc4.4 compilation run: src/kernel/fiasco/src/lib/libk/cxx/function:34: error: ‘cxx::functor<Res(Args ...)>::functor(cxx::functor<Res(Args ...)>&&)’ cannot be defaulted src/kernel/fiasco/src/kern/map_util.cpp: In member function ‘void Mu::Auto_tlb_flush<Mem_space>::global_flush()’: src/kernel/fiasco/src/kern/map_util.cpp:78: error: expected primary-expression before ‘[’ token src/kernel/fiasco/src/kern/map_util.cpp:78: error: expected primary-expression before ‘)’ token src/kernel/fiasco/src/kern/map_util.cpp:741: error: expected primary-expression before ‘[’ token src/kernel/fiasco/src/kern/map_util.cpp:741: error: expected ‘(’ before ‘*’ token src/kernel/fiasco/src/kern/map_util.cpp:741: error: ‘m’ was not declared in this scope src/kernel/fiasco/src/kern/map_util.cpp:741: error: expected ‘(’ before ‘size’

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Booting on Raspberry Pi
by Robert Kaiser 17 Sep '13

17 Sep '13

Hello, i'm currently trying to get Fiasco.OC + L4Re up and running on a Raspberry Pi, but no luck :-( I have gotten as far as building a bootstrap_hello.elf file. According to previous posts here, I should just copy this file to the first partition of a linux-bootable SD card, add an entry like "kernel=bootstrap_hello.elf" to config.txt, and I should see some messages at the serial port as the Pi boots L4. Alas, my Pi stays silent. If I then simply remove the added line from config.txt, leaving everything else the same, Linux boots from the card alright and I can see its messages on the serial port. Thus, I'm confident that my hardware set-up should be OK. I am not absolutely sure wether I got the building of the boot file right. What surprises me is that it is an ELF file: I have previously followed the "Baking Pi" tutorial at http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/. There I used to boot *raw* binaries which expected to be loaded at 0x8000. In contrast, this file here displays as an ELF file with .text starting at 0x01000000. Is that how it should be? The building process also creates a file named "bootstrap_hello", but that is simply a copy of bootstrap_hello.elf. What's the point of this? Thanks a lot for any help Robert Kaiser

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Is mapping database still in use now?
by Sheng-Wei Cheng 15 Sep '13

15 Sep '13

Hi hackers, I've read the paper “µ-kernel Memory Management” and know that, in theory, mapping database is designed for quickly unmaping a page which is recursively mapped to several address spaces. However, is it still in use now in popular implementations like Fiasco.OC? If that is the case, is it used intensively when virtualization on microkernel is involved? (for example, L4Linux etc) Best regards, Lawrence

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vbus problem
by vijay kumar Godavarthy 15 Sep '13

15 Sep '13

Dear all I am using the following code. vbus = l4re_env_get_cap("vbus"); if (l4_is_invalid_cap(vbus)) { printf("Couldn't obtain vbus capability\n"); I am getting the error "Couldn't obtain vbus capability". How to overcome this problem. -- vijay kumar

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How to start DoPe and clients ?
by Rudolf Weber 15 Sep '13

15 Sep '13

Hello, I want to start dope, an fbterminal, and an fb_spectrum, (using l4re-snapshot-2013060718) with the following Start-Script: -- vim:set ft=lua: loader = L4.default_loader; -- Start io vbus_l4linux = loader:new_channel(); local io_buses = { input = loader:new_channel(); fbdrv = loader:new_channel(); }; loader:start( { caps = { sigma0 = L4.cast(L4.Proto.Factory, L4.Env.sigma0):create(L4.Proto.Sigma0); icu = L4.Env.icu; input = io_buses.input:svr(); fbdrv = io_buses.fbdrv:svr(); l4linux = vbus_l4linux:svr(); }, }, "rom/io rom/x86-legacy.devs rom/l4lx-x86.io"); -- Start fb-drv (but only if we need to) local fb = L4.Env.vesa; if (not fb) then fb = loader:new_channel(); loader:start({ caps = { fb = fb:svr(), vbus = io_buses.fbdrv }, log = { "fbdrv", "r" }, l4re_dbg = L4.Dbg.Warn, }, "rom/fb-drv -m 0x117"); end local gui_caps = { svc = loader:new_channel(), dope = loader:new_channel(), }; -- Start dope loader:start( { caps = { vbus = io_buses.input, fb = fb, svc = gui_caps.svc:svr(), dope = gui_caps.dope:svr(), }, }, "rom/l4dope"); local term_srv = loader:new_channel(); print("Start FBterminal "); e=loader:start( { caps = { fb = gui_caps.svc:create(L4.Proto.Goos, "g=640x480"), term = term_srv:svr(), }, log = { "fbterm", "b" }, l4re_dbg = L4.Dbg.Warn, },"rom/fbterminal"); print("Start fb_spectrum"); e2 = loader:start({ caps = { fb = gui_caps.svc:create(L4.Proto.Goos, "g=320x480"), }, log = { "spectrum", "b" }, l4re_dbg = L4.Dbg.Warn, }, "rom/ex_fb_spectrum_cc"); print("fbterminal exited with: " .. e:wait()); print("ex_fb_spectrum exited with: " .. e2:wait()); -------------------- Result: dope starts, but neither the fbterminal nor the ex_fb_specturm_cc is visible. (The kerneldebugger shows, that the Tasks are not existent ...) What is wrong ? Thank you very much Rudolf P.S: I collect my good experience on http://www.infnet.verein.de/betriebssysteme/kleinkernarch/l4/l4re_conf_2013… with mag it was successfull: http://www.infnet.verein.de/betriebssysteme/kleinkernarch/l4/l4re_conf_2013…

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L4Re::Util::Dataspace_svr
by Daniel Müller 15 Sep '13

15 Sep '13

Hi again, I believe the Dataspace_svr dispatch function is missing a case for L4Re::Dataspace_::Allocate (as declared in l4/pkg/l4re/include/dataspace-sys.h) -- I receive this opcode and since there is no handling the result is a return of -L4_ENOSYS (which will make subsequent processing fail). As a quick fix the attached patch works but there should probably also be a hook (virtual function) in the Dataspace_svr class (and maybe some more sophisticated default processing, not sure). Thanks, Daniel

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