Difference between revisions of "KR/ARM"

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(Hosting)
(Hosting)
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==Hosting==
 
==Hosting==
Ideally you have a fast ARM based machine, where you install the distro of choice, building OOo just as usual. Unfortunately I did not have any hardware, so I had to build by emulation.
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Ideally you have a fast ARM based machine, where you install the distro of choice, building OOo just as usual. Unfortunately I did not have any hardware, so I had to build in emulation.
  
 
===QEMU===
 
===QEMU===
User space QEMU vs. system QEMU.
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Obviously the emulator of choice is [http://www.nongnu.org/qemu/about.html QEMU]: "QEMU is a generic and open source machine emulator and virtualizer."
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QEMU does not only allow system emulation, but also process emulation. The former means, that a whole computer is emulated, including boot-up, user-land, kernel-land, hardware and everything. The latter means, that a program compiled e.g. for ARM may be directly executed on x86 or x64. Most important difference for compilation tasks is the difference in execution speed and available memory. A whole system emulation is reasonable slow, and especially for ARM memory size is limited to 256MB, while user-space (or in-process) emulation does only emulate user land, the kernel and everything else may run natively. This is especially interesting, as it allows to mix emulated binaries with native ones, see "afterburner" for some usage scenarios.
  
 
====User Space QEMU====
 
====User Space QEMU====

Revision as of 08:06, 7 May 2009

OOo has been ported to Linux ARM (armel) a while ago by Caolan McNamara. Creating a OOo for ARM just means building it. I did build it on Ubuntu 9.04 ARM, other distros may work as well ...


Hosting

Ideally you have a fast ARM based machine, where you install the distro of choice, building OOo just as usual. Unfortunately I did not have any hardware, so I had to build in emulation.

QEMU

Obviously the emulator of choice is QEMU: "QEMU is a generic and open source machine emulator and virtualizer."

QEMU does not only allow system emulation, but also process emulation. The former means, that a whole computer is emulated, including boot-up, user-land, kernel-land, hardware and everything. The latter means, that a program compiled e.g. for ARM may be directly executed on x86 or x64. Most important difference for compilation tasks is the difference in execution speed and available memory. A whole system emulation is reasonable slow, and especially for ARM memory size is limited to 256MB, while user-space (or in-process) emulation does only emulate user land, the kernel and everything else may run natively. This is especially interesting, as it allows to mix emulated binaries with native ones, see "afterburner" for some usage scenarios.

User Space QEMU

To be able to utilize user space QEMU, we need the target distribution as a directory on the build system, so that we can enter it with "chroot". QEMU in system mode can than be booted on this file system with NFS root.

System QEMU

NFS root

Build times

jaunty with "coreutils bzip2 bash tcsh emdebian epm fastjar dpkg" 4:40

After Burner

Emdebian

Using user space QEMU combined with the Emdebian toolchain gives the shortest build times (~6H).

Build Issues

  • sal/typesconfig/typesconfig.c: had to patch away #ifdef ... || ARM32 (fix in cmcfixes56 where the actual correct alignments for real hardware is determined)
  • ICU needs to not be build with g++ 4.3: ... internal compiler error - used 4.2 instead (optimizing error - g++ 4.3.2 with -O0 works as well)
  • dpkg: error processing openoffice.org-ure_1.5.0-3_linux-2.6-arm.deb (--install):
package architecture (arm) does not match system (armel)
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