August 2013 - l4-hackers - example.com Site

Issue in getting Virtual Hardware devices
by Raja Sekhar 10 Aug '13

10 Aug '13

Hello to all, I'm working on L4 fiasco. In that I want to read the virtual hardware devies. for tha I'm running the code from * l4/pkg/example/sys/ux-vhw/main.c *** * 10 #include <l4/sys/ipc.h> 11 #include <l4/sys/vhw.h> 12 #include <l4/util/util.h> 13 #include <l4/util/kip.h> 14 #include <l4/re/env.h> 15 16 #include <stdlib.h> 17 #include <stdio.h> 18 19 static void print_entry(struct l4_vhw_entry *e) 20 { 21 printf("type: %d mem start: %08lx end: %08lx\n" 22 "irq: %d pid %d\n", 23 e->type, e->mem_start, e->mem_size, 24 e->irq_no, e->provider_pid); 25 } 26 27 int main(void) 28 { 29 l4_kernel_info_t *kip = l4re_kip(); 30 struct l4_vhw_descriptor *vhw; 31 int i; 32 33 if (!kip) 34 { 35 36 printf("KIP not available!\n"); 37 return 1; 38 } 39 40 vhw = l4_vhw_get(kip); 41 42 if(vhw) 43 { 44 printf("kip at %p, vhw at %p\n", kip, vhw); 45 printf("magic: %08x, version: %08x, count: %02d\n", 46 vhw->magic, vhw->version, vhw->count); 47 48 for (i = 0; i < vhw->count; i++) 49 print_entry(l4_vhw_get_entry(vhw, i)); 50 } 51 return 0; 52 }** *In the above code at *line no 40* after *calling inline function l4_vhw_get(kip)* I'm getting *vhw=NULL. *and the definition of inline function is from* l4sys/include/vhw.h *is as follows* 80 enum { 81 L4_VHW_MAGIC = 0x56687765, 82 }; 83 84 static inline struct l4_vhw_descriptor * 85 l4_vhw_get(l4_kernel_info_t *kip) L4_NOTHROW 86 { 87 struct l4_vhw_descriptor *v 88 = (struct l4_vhw_descriptor *)(((unsigned long)kip) + kip->vhw_offset); 89 90 if (v->magic == L4_VHW_MAGIC) 91 return v; 92 93 return NULL; 94 } *Here* at line no 90, the v->magic *is having a value of* 0x4BE6344C *which is not equal to* L4_VHW_MAGIC *My qestion is why I'm getting different magic value Instead of 0x56687765, and how can I get correct magic value*. *If there are no virtual hardware device how can i create and integrate into my system........* * * * * *Thanks, Raja Sekhar

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Setting physical CPU for a task
by Lluís Vilanova 06 Aug '13

06 Aug '13

Hi, I've been looking for a way to run some sort of ping-pong example where each task runs on either the same or different CPUs. I've been unable to see if moe's config files allow to start tasks pinned to a specific CPU, and after running the "thread_migrate" example, looks like only one CPU (CPU00) is always used: $ make -C obj/l4/amd64/ qemu E=thread_migrate QEMU_OPTIONS="-serial stdio -vnc ::59000 -smp 2" [...] Not using serial hack in slow timer handler. CPU[0]: AuthenticAMD (6:2:3:0)[00000623] Model: QEMU Virtual CPU version 1.5.1 at 3092MHz 255/512 Entry I TLB (4K pages) 255 Entry I TLB (4M pages) 255/512 Entry D TLB (4K pages) 255 Entry D TLB (4M pages) 64 KB L1 I Cache (2-way associative, 64 bytes per line) 64 KB L1 D Cache (2-way associative, 64 bytes per line) 512 KB L2 U Cache (8-way associative, 64 bytes per line) Freeing init code/data: 20480 bytes (5 pages) [...] Ned says: Hi World! Ned: loading file: 'rom/thread_migrate.cfg' migrate | Found 4 CPUs. migrate | Created 12 threads. migrate | Migrated Thread00 -> CPU00 migrate | Migrated Thread01 -> CPU00 migrate | Migrated Thread02 -> CPU00 migrate | Migrated Thread03 -> CPU00 migrate | Migrated Thread04 -> CPU00 migrate | Migrated Thread05 -> CPU00 migrate | Migrated Thread06 -> CPU00 migrate | Migrated Thread07 -> CPU00 migrate | Migrated Thread08 -> CPU00 migrate | Migrated Thread09 -> CPU00 migrate | Migrated Thread10 -> CPU00 migrate | Migrated Thread11 -> CPU00 migrate | Migrated Thread00 -> CPU00 migrate | Migrated Thread01 -> CPU00 migrate | Migrated Thread02 -> CPU00 migrate | Migrated Thread03 -> CPU00 migrate | Migrated Thread04 -> CPU00 migrate | Migrated Thread05 -> CPU00 migrate | Migrated Thread06 -> CPU00 migrate | Migrated Thread07 -> CPU00 migrate | Migrated Thread08 -> CPU00 migrate | Migrated Thread09 -> CPU00 migrate | Migrated Thread10 -> CPU00 migrate | Migrated Thread11 -> CPU00 [... same output forever ...] I've modified "src/l4/conf/modules.list" to add the "thread_migrate" test, and I'm using l4re-snapshot-2013060718, with multiprocessing (with a maximum of 4) enabled on fiasco. Looks like the benchmark always detects (L4::Scheduler::info) the number of maximum CPUs configured in fiasco, but not the number of CPUs provided by QEMU (only CPU 0 is online). Am I missing some step to set all CPUs online? Is it possible to have MOE start tasks pinned to a specific CPU? Thanks a lot, Lluis -- "And it's much the same thing with knowledge, for whenever you learn something new, the whole world becomes that much richer." -- The Princess of Pure Reason, as told by Norton Juster in The Phantom Tollbooth

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Re: l4-hackers Digest, Vol 124, Issue 4
by Иван Филиппов 06 Aug '13

06 Aug '13

Hi Lluis, Have pretty much the same as you sad - can't load both qemu for unknown memory address, neither for grub2 for Ubuntu 13.04, but it compiles well. I`ll ask what happens tomorrow on upcoming russian Fiasco/Virtualization school with Bjorn Doebel at al. and tell you what happens. Probably the best choose is Qemu emulator, if you don't have already written software, not to reload system every time you need. I compiled with i386 option both FiascoOC/L4RE and them works well. just as here: http://os.inf.tu-dresden.de/pipermail/l4-hackers/2011/004894.html http://os.inf.tu-dresden.de/pipermail/l4-hackers/2011/<http://os.inf.tu-dresden.de/pipermail/l4-hackers/2011/004894.html> 004894.html<http://os.inf.tu-dresden.de/pipermail/l4-hackers/2011/004894.html> I have 4.7 compiler too. Best wishes, 2013/8/5 <l4-hackers-request(a)os.inf.tu-dresden.de> > Send l4-hackers mailing list submissions to > l4-hackers(a)os.inf.tu-dresden.de > > To subscribe or unsubscribe via the World Wide Web, visit > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > or, via email, send a message with subject or body 'help' to > l4-hackers-request(a)os.inf.tu-dresden.de > > You can reach the person managing the list at > l4-hackers-owner(a)os.inf.tu-dresden.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of l4-hackers digest..." > > > Today's Topics: > > 1. Unable to boot Fiasco.OC on amd64 (Llu?s Vilanova) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 04 Aug 2013 22:44:24 +0300 > From: Llu?s Vilanova <vilanova(a)ac.upc.edu> > To: l4-hackers(a)os.inf.tu-dresden.de > Subject: Unable to boot Fiasco.OC on amd64 > Message-ID: <87eha95jhj.fsf(a)fimbulvetr.bsc.es> > Content-Type: text/plain; charset="us-ascii" > > Hi there, > > After having to play with the load addresses of both fiasco and some of the > modules [1], I've been able to boot fiasco, but only to find it chokes on > some > assertion, immediately following a pager warning (see error.jpg > screenshot). > > Sorry for using a screenshot, but I've been unable to make the serial > console > work, so no copy&paste is available. > > As I'm new to L4, I don't know if the error is due to my changes or due to > some > other mis-configuration on the boot process. See the attached grub2.txt > for the > GRUB2 entries I've tried (the error corresponds to the first entry). > > I'm using the l4re-core-2013060718 tarball, all compiled on a debian > testing > (gcc 4.7.3). > > Any help on the boot or the serial console support is much appreciated. > > > Thanks a lot, > Lluis > > [1] To avoid some region overlaps, see attached l4.patch, and memory.jpg > for the > memory range configuration of the machine. > >

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mmap2 on L4Linux rev 37
by Sebastian Sumpf 06 Aug '13

06 Aug '13

Hi L4 hackers, recently I started to use L4Linux r37 on ARM and experienced some issues with the 'sys_mmap_pgoff'-system call. When a user-level task tried to map a file the 'pgoff' parameter was usually bogus. Doing a little research I found that it was caused by the 'sys_mmap2' implementation in 'entry.S'. The function overwrites the 'pgoff' argument on the stack with r5 (as it is usually passed from user land), since in L4Linux this code gets called from the dispatch routine, 'pgoff' was set to whatever r5 was, and thus leading to bus errors later on. Cheers, Sebastian -- Sebastian Sumpf Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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why Fiasco kernel is named as fiasco
by Raja Sekhar 05 Aug '13

05 Aug '13

Hello to all, I just want to know that why fiasco micro-kernel named as fiasco ..... can you please give me the answer....... * Thanks,* Raja Sekhar

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Unable to boot Fiasco.OC on amd64
by Lluís Vilanova 04 Aug '13

04 Aug '13

Hi there, After having to play with the load addresses of both fiasco and some of the modules [1], I've been able to boot fiasco, but only to find it chokes on some assertion, immediately following a pager warning (see error.jpg screenshot). Sorry for using a screenshot, but I've been unable to make the serial console work, so no copy&paste is available. As I'm new to L4, I don't know if the error is due to my changes or due to some other mis-configuration on the boot process. See the attached grub2.txt for the GRUB2 entries I've tried (the error corresponds to the first entry). I'm using the l4re-core-2013060718 tarball, all compiled on a debian testing (gcc 4.7.3). Any help on the boot or the serial console support is much appreciated. Thanks a lot, Lluis [1] To avoid some region overlaps, see attached l4.patch, and memory.jpg for the memory range configuration of the machine. menuentry "L4" { multiboot /boot/l4/bootstrap -serial module /boot/l4/fiasco /fiasco -serial_esc module /boot/l4/l4f/sigma0 /sigma0 module /boot/l4/l4f/moe /moe module /boot/l4/l4f/hello /hello } menuentry "L4 - L4re" { multiboot /boot/l4/bootstrap -serial module /boot/l4/fiasco /fiasco -serial_esc module /boot/l4/l4f/sigma0 /sigma0 module /boot/l4/l4f/moe /moe --init=rom/hello module /boot/l4/l4f/l4re /l4re module /boot/l4/l4f/hello /hello } -- "And it's much the same thing with knowledge, for whenever you learn something new, the whole world becomes that much richer." -- The Princess of Pure Reason, as told by Norton Juster in The Phantom Tollbooth

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Use of the PC value in interrupt/exception handlers
by Piyus Kedia 03 Aug '13

03 Aug '13

Dear all, We are working on developing a dynamic binary translator for the kernel. Towards this, we wanted to confirm if the interrupted PC value pushed on stack by an interrupt/exception is used by the interrupt/exception handlers? For example, is the PC value compared against a fixed address to determine the handler behaviour (like Linux's page fault handler compares the faulting PC against an exception table, to allow functions like copy_from_user to fault). Basically, we are wondering if it is safe to replace the pushed PC value on stack by another value. This would be safe if the PC value is only used for returning from interrupt, or for reading contents at that PC address (e.g., to decode the instruction at current PC). It would be unsafe if the value of the address itself is meaningful to the handler. We found that in FreeBSD segment-not-present exception handler checks the trapped PC value against some fixed kernel PC by looking at the code, except that it is only used for debugging purposes. It would be nice if somebody could also confirm this. Thanks, Piyus

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l4linux: l4x_setup_memory:Cant get main memory
by Rudolf Weber 01 Aug '13

01 Aug '13

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Fwd: Interrupt Handlers
by Piyus Kedia 01 Aug '13

01 Aug '13

Hi All, I am working on dynamic binary translator. Please tell me if anybody know if in L4-microkernel interrupted kernel PC is ever used in interrupt handlers? Thanks and regards, Piyus

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Using the tmpfs library
by Michael Weiß 01 Aug '13

01 Aug '13

Hi, I want to do some file operations in a native l4re application. using fopen, fgetc, fprintf... from libc. I know that this is possible for the rom filesystem. However, I want to create new files during runtime which are also writable. I found the VFS implementation l4/pkg/tmpfs. but I do not really understand how that VFS stuff works, as there also is no header file for tmpfs. How can I access the tmpfs functionality within my application? For my application it would be sufficient to just have temporary files, which I think is exactly what the tmpfs lib provides. I already linked the tmpfs lib to my application and tried to use mount from sys/mount.h. However, I have no idea which parameters and how the path than has to look like for fopen. Is there some example code which shows howto use this lib in an application? Thanks, Michael

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