July 2011 - l4-hackers - example.com Site

L4Re Library Usage
by Wesley Miaw 30 Jul '11

30 Jul '11

I have been able to get my module to compile as an ext-pkg. However I'm a little confused by the description of L4Re listed at http://os.inf.tu-dresden.de/L4Re/overview.html What exactly do I need to replace in my code to use the L4Re C or C++ libraries, or libstdc++ etc.? I didn't get any compilation errors with code that directly calls malloc() and I saw some other modules call malloc() too. But I would have thought all memory allocation/deallocation needs to be changed to use an L4 function. When I looked inside packages like cxx or libstdc++ it doesn't actually look like these are replacements for the GNU headers or libraries. Is the only code I need to have use L4Re functions and types the code that is going to handle message receiving and sending? Everything else could be as if it was not part of L4? Thanks, Wes

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[ANNOUNCE] NOVA Microhypervisor 0.4 prerelease
by Udo A. Steinberg 28 Jul '11

28 Jul '11

Hi, The NOVA project is happy to announce that there is a new prerelease of the NOVA microhypervisor available for download at http://www.hypervisor.org/ under the terms of the GNU General Public License version 2. NOVA is based on a modern microhypervisor written in C++ and assembler. The current implementation runs on multi-core x86 machines that support ACPI, under QEMU (including VM support), and as a microkernel in a virtual machine on top of itself. NOVA makes use of hardware virtualization features such as Intel VT-x/VT-d or AMD-V, and facilitates running unmodified guest operating systems in virtual machines with near-native performance. Among other things, the new prerelease improves the security of device- and interrupt assignment by using capabilities for these operations. There is also a new hypercall for interacting with the scheduler. At the same time, we've released a new version of the NOVA Userland (NUL). While there are few user-visible changes, a lot has changed under the hood. We have integrated a central admission server that is going to implement global policies for CPU time distribution in a future release. Another notable development is rudimentary libvirt support, which will eventually replace the old configuration syntax. Cheers, - Udo

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Re: l4-hackers Digest, Vol 99, Issue 18
by Wesley Miaw 28 Jul '11

28 Jul '11

> On Mon Jul 25, 2011 at 16:43:09 -0700, Wesley Miaw wrote: >> I'm trying to add a new lib/server module to L4 but I'm having some >> trouble. I followed the snapshot top-level README suggestion to >> place the new code in an external directory, so I placed it into >> src/mymodule/ next to src/l4re and src/l4linux. Then I created a >> Makefile under src/mymodule/src/ based on the example with include >> $(L4DIR)/mk/lib.mk. >> >> However, this doesn't appear to be working. $(L4DIR)/mk/Makeconf is >> complaining that files existing inside the obj/l4/... directory are >> not to be found in the obj/mymodule/... directory. (I tried to copy >> the obj/... logic found in the top-level Makefile.) >> >> Is the README's suggestion accurate? > > I think so. Could you show me some of the failed output + surroundings > to better judge what's going on? My bad. I didn't realize the build directory (O=) had to be the l4 obj directory for my own packages. (Missed that part of the README.) It's working for me now. Thanks! -- Wesley Miaw wesley(a)wesman.net

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No configuration file found in build directory
by Wesley Miaw 26 Jul '11

26 Jul '11

I'm trying to add a new lib/server module to L4 but I'm having some trouble. I followed the snapshot top-level README suggestion to place the new code in an external directory, so I placed it into src/ mymodule/ next to src/l4re and src/l4linux. Then I created a Makefile under src/mymodule/src/ based on the example with include $(L4DIR)/mk/ lib.mk. However, this doesn't appear to be working. $(L4DIR)/mk/Makeconf is complaining that files existing inside the obj/l4/... directory are not to be found in the obj/mymodule/... directory. (I tried to copy the obj/... logic found in the top-level Makefile.) Is the README's suggestion accurate? Thanks, -- Wesley Miaw wesley(a)wesman.net

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transfer_msg_items
by Chen Tian 21 Jul '11

21 Jul '11

Hello, Why was a sender's send item (e.g. mr[0] and mr[1] ) merged and stored into the receiver's mr[0]? Basically I have trouble understanding the following code. *rcv_words=(item->b.raw() & ~0x0ff7) | (sfp.raw())&0x0ff0); rcv_word +=2 ; Why didn't we use receiver's mr[1] as well? In the case of page fault handling IPC, the pf address stored in sender's mr[1] is not used ? Thanks. Chen

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what is the difference between the 2 methods of booting hello demo
by cheng guanghui 19 Jul '11

19 Jul '11

Hello: In the modules.list there are 2 entires to boot hello demo as following: entry hello roottask moe --init=rom/hello module l4re module hello entry hello-cfg roottask moe rom/hello.cfg module l4re module ned module hello.cfg module hello The booting logs are following separately : hello MOE: Hello world MOE: found 117648 KByte free memory MOE: found RAM from 1000 to 75c7000 MOE: allocated 117 KByte for the page array @0x1000 MOE: virtual user address space [0-bfffffff] MOE: rom name space cap -> [C:501000] BOOTFS: [136d000-1470e6d] [C:503000] l4re BOOTFS: [1471000-153030b] [C:504000] hello MOE: cmdline: /home/cheng/TUDOS/Src/l4re-snapshot-2011062216/obj/l4/x86/bin/x86_586/l4f/moe --init=rom/hello MOE: Starting: rom/hello MOE: loading 'rom/hello' Hello World! Hello World! Hello World! hello-cfg MOE: Hello world MOE: found 115604 KByte free memory MOE: found RAM from 1000 to 75c7000 MOE: allocated 117 KByte for the page array @0x1000 MOE: virtual user address space [0-bfffffff] MOE: rom name space cap -> [C:501000] BOOTFS: [136d000-1470e6d] [C:503000] l4re BOOTFS: [1471000-166e572] [C:504000] ned BOOTFS: [166f000-166f066] [C:505000] hello.cfg BOOTFS: [1670000-172f30b] [C:506000] hello MOE: cmdline: /home/cheng/TUDOS/Src/l4re-snapshot-2011062216/obj/l4/x86/bin/x86_586/l4f/moe rom/hello.cfg MOE: Starting: rom/ned rom/hello.cfg MOE: loading 'rom/ned' Ned says: Hi World! Ned: loading file: 'rom/hello.cfg' hello | Hello World! hello | Hello World! hello | Hello World! hello | Hello World! hello | Hello World! hello | Hello World! hello | Hello World! So hello demo could be booted whatever from Ned or Moe directly. In the document Ned is described as this "The main thing to do here is to coordinate the startup of services and applications as well as to provide the communication channels for them". Does it mean "We use Ned just because we need to dynamically create IPC gate (channel) between different applications". If there is no need to use IPC gate we can use Moe directly to boot application. is it correct? Thanks. Warm regards. Cheng Guanghui

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how can i understand this description in the l4re-source document?
by cheng guanghui 19 Jul '11

19 Jul '11

Hello: In the page 19 of the l4re-source document there is a description about caps as following: Caps The table with application-specific named capabilities (default is an empty table). If the table does not contain a capability with the name ’rom’, the ’rom’ capability from Ned’s initial caps is inserted into the table. How can i understand "If the table does not contain a capability with the name ’rom’, the ’rom’ capability from Ned’s initial caps is inserted into the table." Thanks. Warm regards. Cheng Guanghui

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writing my own filesystem for L4
by Michal Schulz 19 Jul '11

19 Jul '11

Hello. I'm going to write a filesystem for L4, using the tmpfs (l4/pkg/tmpfs) as a starting point. However, I would like to know whether there are any tools I could use to test the filesystem. The tool I would love to have should display all registered filesystem and should allow me to walk through filesystem's directory trees. Is there such a tool or example application? Are there any packages in L4 which use VFS layer at all? regards, Michal. -- Michal Schulz

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Re: l4-hackers Digest, Vol 99, Issue 11
by Chen Tian 18 Jul '11

18 Jul '11

Hi Adam, I don't have a separate PHDR for ctors. I got this problem when I put ctors into the text section. Now I have moved ctors into the data section and the problem disappeared. Any ideas? Another questions is why ktext=0x90909090 in the ld file of fiasco.oc? Is this value randomly chosen? Thanks. On Sat, Jul 16, 2011 at 3:00 AM, <l4-hackers-request(a)os.inf.tu-dresden.de> wrote: > 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. Re: write my own root task. (Adam Lackorzynski) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 15 Jul 2011 23:20:50 +0200 > From: Adam Lackorzynski <adam(a)os.inf.tu-dresden.de> > To: l4-hackers(a)os.inf.tu-dresden.de > Subject: Re: write my own root task. > Message-ID: <20110715212050.GB5040(a)os.inf.tu-dresden.de> > Content-Type: text/plain; charset=iso-8859-1 > > > On Thu Jul 14, 2011 at 15:15:25 -0700, Chen Tian wrote: >> I am trying to use C++ to write my own root task. I found that if I >> declare a static or global object, bootstrap complains that two >> regions belonging to my root task overlapped and thus cannot proceed. >> Why does my root task have two conflicting regions? According to the >> bootstrap report, they both have the correct starting address, but one >> ends just at the global object's ctor in .ctors section, while the >> other region covers the entire program. >> If the .ctors section is empty then everything is fine. Any ideas? > > I wonder why you have an own PHDR for ctors? How many do you have? > > > Adam > -- > Adam adam(a)os.inf.tu-dresden.de > Lackorzynski http://os.inf.tu-dresden.de/~adam/ > > > > ------------------------------ > > _______________________________________________ > l4-hackers mailing list > l4-hackers(a)os.inf.tu-dresden.de > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > > > End of l4-hackers Digest, Vol 99, Issue 11 > ****************************************** >

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write my own root task.
by Chen Tian 15 Jul '11

15 Jul '11

Hello, I am trying to use C++ to write my own root task. I found that if I declare a static or global object, bootstrap complains that two regions belonging to my root task overlapped and thus cannot proceed. Why does my root task have two conflicting regions? According to the bootstrap report, they both have the correct starting address, but one ends just at the global object's ctor in .ctors section, while the other region covers the entire program. If the .ctors section is empty then everything is fine. Any ideas? Thanks. Chen

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