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Diffstat (limited to 'xml/htdocs/proj/en/base/embedded/handbook/cross-qemu.xml')
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diff --git a/xml/htdocs/proj/en/base/embedded/handbook/cross-qemu.xml b/xml/htdocs/proj/en/base/embedded/handbook/cross-qemu.xml new file mode 100644 index 00000000..2fa4a021 --- /dev/null +++ b/xml/htdocs/proj/en/base/embedded/handbook/cross-qemu.xml @@ -0,0 +1,112 @@ +<?xml version='1.0' encoding='UTF-8'?> +<!DOCTYPE sections SYSTEM "/dtd/book.dtd"> +<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/proj/en/base/embedded/handbook/cross-qemu.xml,v 1.4 2010/08/30 03:59:07 nightmorph Exp $ --> + +<!-- The content of this document is licensed under the CC-BY-SA license --> +<!-- See http://creativecommons.org/licenses/by-sa/2.5 --> + +<sections> + +<abstract> +How To compile with QEMU user. +</abstract> + +<version>0.2</version> +<date>2010-02-14</date> + +<section> +<title>Usage</title> +<body> + +<p> +In order to take advantage of qemu-user mode we need to do a few things. First +we need to merge the main package we are going to need. Note the use of the +<c>static</c> use flag. +</p> + +<pre caption="Installing qemu-user"> +# <i>USE=static emerge -b1 app-emulation/qemu-user</i> +</pre> + +<p> +Next we need to build the kernel module <c>binfmt_misc</c>. +Add this to your kernel <path>.config</path>: +<c>CONFIG_BINFMT_MISC=m</c> or <c>CONFIG_BINFMT_MISC=y</c>. +If this module is not built already, then the devel host will require a +reboot after the kernel update and modules_install. +</p> + +<p> +Mount the <c>binfmt_misc</c> handler if it's not already, then we need to +register our format with the kernel via the procfs. +</p> + +<pre caption="binfmt_misc"> +# <i>[ -d /proc/sys/fs/binfmt_misc ] || modprobe binfmt_misc</i> +# <i>[ -f /proc/sys/fs/binfmt_misc/register ] || mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc</i> +<comment>(Do not register a handler that matches the host machine)</comment> +# <i>echo ':arm:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/</i>qemu-wrapper<i>:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':armeb:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-armeb:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':alpha:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x26\x90:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-alpha:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':mips:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-mips:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':mipsel:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-mipsel:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':ppc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-ppc:' > /proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':sh4:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff\xff:/usr/bin/qemu-sh4:' >/proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':sh4eb:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-sh4eb:' >/proc/sys/fs/binfmt_misc/register</i> +# <i>echo ':sparc:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02:\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-sparc:' > /proc/sys/fs/binfmt_misc/register</i> + +</pre> + +<pre caption="Enter/Exit the chroot"> +<comment>(Download your desired stage tarball)</comment> +# <i>wget http://arch-stageball</i> +<comment>(Unpack the tarball)</comment> +# <i>tar -xzvf arch-stageball</i> +# <i>cd arch-stageball</i> +<comment>(Install the static qemu-user into the chroot)</comment> +# <i>ROOT=$PWD/ emerge -K qemu-user</i> +# <i>mkdir -p usr/portage</i> +<comment>(Mount the required directories)</comment> +# <i>mount --bind /usr/portage usr/portage</i> +# <i>mount --bind /proc proc</i> +# <i>mount --bind /sys sys</i> +<comment>(Chroot into the environment)</comment> +# <i>chroot . /bin/busybox mdev -s</i> +# <i>chroot . /bin/bash --login</i> +<comment>(Unmount stuff when not in use)</comment> +# <i>umount usr/portage</i> +# <i>umount sys</i> +# <i>umount proc</i> +</pre> + +<p> +Sometimes we'll need to pass additional args to QEMU (cpu model), so we'll +create a wrapper script that'll call QEMU with it. +</p> + +<pre caption="qemu-wrapper"> +#include <stdio.h> +#include <unistd.h> + +int main(int argc, char **argv, char **envp) { + char *newargv[argc + 3]; + + newargv[0] = argv[0]; + newargv[1] = "-cpu"; + newargv[2] = "<i>cortex-a8</i>"; + + memcpy(&newargv[3], &argv[1], sizeof(*argv) * (argc - 1)); + newargv[argc + 2] = NULL; + return execve("<i>/usr/bin/qemu-arm</i>", newargv, envp); +} +</pre> + +<p> +Compile the wrapper with <c>gcc -static qemu-wrapper.c -o qemu-wrapper</c> and +copy into the chroot. Notice the first example arm entry in the +<c>binfmt_misc</c> section uses this method. +</p> + +</body> +</section> +</sections> |