Manpages

NAME

make−kpkg − build Debian kernel packages from Linux kernel sources

SYNOPSIS

make−kpkg [options] [target [target ...]]

DESCRIPTION

This manual page explains the Debian make−kpkg utility, which is used to create the kernel related Debian packages. This utility needs to be run from a top level Linux kernel source directory, which has been previously configured (unless you are using the configure target). Normally, if kernel−package does not find a .config file in the current directory, it tries very hard to get an appropriate one (usually a config file already tailored for Debian kernels for that architecture), and then calls make oldconfig to let the user answer any new questions. However, this might still result in an inappropriate configuration, you are encouraged to configure the kernel by the usual means before invoking make−kpkg.

Typically, make-kpkg should be run under fakeroot,

make−kpkg −−rootcmd fakeroot kernel_image

but instead you run this command as root (this is not recommended), or under fakeroot, or tell make−kpkg how to become root (not recommended either, fakeroot is perhaps the safest option), like so:

make−kpkg −−rootcmd sudo kernel_image

The Debian package file is created in the parent directory of the kernel source directory where this command is run.

Also, please note that some versions of gcc do not interact well with the kernel source. You may control which version of gcc used in kernel compilation by setting the Makefile variables CC and HOSTCC in the top level kernel Makefile. You can do this simply by setting the environment variable MAKEFLAGS. To observe, try:

% KBUILD_VERBOSE=1 MAKEFLAGS="CC=gcc−4.4" make−kpkg configure

Please note that the kernel Makefile might pay attention to other variables (for instance KCFLAGS ). This can be addressed like so:

% KBUILD_VERBOSE=1 MAKEFLAGS=’CC=gcc−4.4 KCFLAGS="-march=athlon64"’ make−kpkg configure

The KBUILD_VERBOSE shows the details of the commands being run. (please see the top level kernel Makefile for variables that can be set).

WARNING: Do NOT set the −j option in MAKEFLAGS directly, this shall cause the build to fail. Use CONCURRENCY_LEVEL as specified below. There is also a −j flag that can be used.

OPTIONS

−−revision number

Changes the version number for the packages produced to the argument number. This has certain constraints: the version must start with a digit. the version may contain only alphanumerics and the characters ~ + . (tilde, full stop and plus) and must contain a digit. (Look at the Policy manual for details). Optionally, you may prepend the revision with a digit followed by a colon (:). The default is 10.00.Custom unless the environment variable DEBIAN_REVISION_MANDATORY is set, in which case an error is generated if the revision is not set on the command line or the configuration file. Hint: You may set it to $(version)-<foo> in the configuration file to get the upstream version number prepended to your custom string <foo>.

−−append−to−version foo
−−append_to_version foo

This argument (foo) is appended to the value of the EXTRAVERSION variable present in the kernel Makefile. Since EXTRAVERSION is a component of the kernel version, it is also added to the Debian package name, and, as such must obey the policy governing the package name. That means it may contain only lowercase alphanumerics and the characters ~ − + . (tilde, full stop, hyphen, and plus). Uppercase letters are not permitted under the Policy for a new package. If the environment variable IGNORE_UPPERCASE_VERSION is set, make−kpkg shall lower case version numbers set in the Makefile or in the localversion file. This option overrides the environment variable APPEND_TO_VERSION.

−−added−modules foo
−−added_modules foo

The argument should be a comma separated list of additional add−on modules (not in the main kernel tree) that you wish to build when you invoke the modules_blah targets. You may give full path names of the directory the modules reside in, or just the module name if it can be found in MODULE_LOC, which defaults to /usr/src/modules. The default is that all modules in MODULE_LOC, are compiled when the modules_blah targets are invoked.

−−arch foo

This is useful for setting the architecture when you are cross compiling. If you are not cross compiling, the architecture is determined automatically. The same effect can be achieved by setting the environment variable KPKG_ARCH. The value should be whatever DEB_HOST_ARCH_CPU contains when dpkg−architecture is run on the target machine, or it can be another architecture in a multi−arch set (like i386/amd64).

−−cross−compile foo
−−cross_compile foo

This is useful for setting the target string when you are cross compiling. Use the dummy target "−" if you are building for other arches of a multiarch set, like i386/amd64. The same effect can be achieved by setting the environment variable. Please note that this does not in any way set the compiler the kernel build process shall use; if the default compiler that the build process comes up with is not the one desired, please explicitly specify the compiler that should be used. CROSS_COMPILE

−−subarch foo

Some architectures (the Alpha, and the m68k) require a different kernel for each sub−architecture. This option provides a way of specifying it as an argument to make−kpkg. Please note that additional support for sub−architectures may be required in the kernel sources to actually make this do anything. The same effect can be achieved by setting the environment variable KPKG_SUBARCH.

−−arch−in−name
−−arch_in_name

This option uses an extended name for the kernel image package by embedding the sub−architecture in the image name, so one could write a script to create multiple sub−architectures one after the other. You may also do this by setting the environment variable ARCH_IN_NAME. Please note that only the package name is affected, not modules locations etc.

−−pgpsign name

Set the string used to sign the changes file for any external modules in /usr/src/modules/ using PGP. This option will override the builtin default and the site wide customizations stored in the file /etc/kernel−pkg.conf or ~/.kernel−pkg.conf.

−−config target

Change the type of configure done from the default oldconfig. target must be one of oldconfig, config, menuconfig, gconfig, nconfig, xconfig, randconfig, defconfig, allmodconfig, allyesconfig, allnoconfig, old, menu, g, or x.

Note however that make−kpkg scans the config file at start up for some options, notably the fact that modules are enabled or not, so toggling the status during the delayed configuration results in an error. If needed, create the configuration file as close to the desired one before calling make−kpkg with this switch.

−−targets

Prints out a list of known targets. See the Section Targets below.

−−noexec

Pass a −n option to the make process so that commands are merely printed to the screen but not actually executed. This is very useful for debugging.

−−verbose

This calls make with the −V=1 option, which calls out the top level Make commands, also useful in seeing what is happening.

−−initrd

If make−kpkg is generating a kernel−image package, arrange to convey to the hook scripts run from the post installation maintainer scripts that this image requires an initrd, and that the initrd generation hook scripts should not short circuit early. Without this option, the example initramfs hook scripts bundled in with kernel-package will take no action on installation. The same effect can be achieved by setting the environment variable INITRD to any non empty value. Please note that unless there are hook scripts in /etc/kernel or added into the hook script parameter of /etc/kernel-img.conf, no initrd will be created (the bundled in example scripts are just examples -- user action is required before anything happens). On most systems, however initramfs-tools installs scripts (since version 0.94 (and they have respected the INITRD variable since 0.98)). dracut also does this.

−−jobs number
−j number

Set the environment variable CONCURRENCY_LEVEL to number.

−−overlay−dir /path/to/directory

The specified directory should contain files that will be placed in the ./debian directory of the kernel sources, in preparation to building the debian packages. The files will replace anything in /usr/share/kernel-package that would normally be placed there, and it is up to the user to make sure that the files in the overlay directory are compatible with make-kpkg. If you break make-kpkg with an overlay file, you get to keep the pieces. The same effect can be achieved by setting the environment variable KPKG_OVERLAY_DIR.

Please note that overlay−dir/Control and overlay-dir/changelog are special, and variable substitution is performed on these files. Use /usr/share/kernel−package/Control and /usr/share/kernel−package/changelog files as templates.

If a overlay−dir/post−install executable (or executable script) exists, it shall be run immediately after ./debian is populated. The script shall be executed in the ./debian directory. This can be used, for instance, to delete files the user does not want, or to take actions other than simple replacement.

−−rootcmd foo

The command that provides a means of gaining super user access (for example, ’sudo’ or ’fakeroot’) as needed by dpkg−buildpackage’s −r option. This option does not work for three of the targets, namely, binary, binary−indep, and binary−arch. For those targets the entire make−kpkg command must be run as (fake)root.

−−stem foo

Call the packages foo−* instead of kernel−*. This is useful in helping transition from calling the packages kernel−* to linux−* packages, in preparation for non−linux kernels in the distribution. The default is linux. The stem, since it is the initial part of a package name must consist only of lower case letters (’a-z’), digits (’0-9’), plus (’+’) and minus (’-’) signs, and periods (’.’). It must be at least two characters long and must start with an alphanumeric character.

The options maybe shortened to the smallest unique string, and may be entered with either a − or a −− prefix, and you may use a space or an = symbol between an option string and a value. You may also use the form option=value; for details these and other variant forms supported, please read Getopt::Long(3perl).
CONCURRENCY_LEVEL

If defined, this environment variable sets the concurrency level of make used to compile the kernel and the modules set using −j flags to the sub make in the build target of make−kpkg. Should be a (small) integer, if used. You can get the current number of CPUs using the command:

grep −c ’^processor’ /proc/cpuinfo

WARNING: Do NOT set the −j option in MAKEFLAGS directly, this shall call the build to fail. It is possible to set −j as a make-kpkg argument.

TARGETS

buildpackage

This target runs the targets clean, and binary, and produces the complete package using dpkg−buildpackage.

binary−indep

This target produces the arch independent packages by running the targets kernel_source, kernel_manual and kernel_doc. However, this also requires make-kpkg to be run as root (or fakeroot), since −−rootcmd will not work.

binary−arch

This target produces the arch dependent packages by running the targets kernel_headers and kernel_image. However, this also requires make-kpkg to be run as root (or fakeroot), since −−rootcmd will not work.

kernel_source

This target produces a debianised package of the Linux kernel sources. If the environment variable SOURCE_CLEAN_HOOK points to an executable, then that executable shall be run from the temporary (top) directory of the kernel sources just before packaging it, ./debian/tmp−source/usr/src/kernel−source−X.X.XX, so people may take any action they see fit (remove arch trees, prune version control directories, find . −type d −name CVS −prune −exec rm −rf {} ; etc.). This has no effect on anything other than the kernel sources that are being packaged -- if the script operates on the current directory and its children, the original source tree should remain intact. The environment variables HEADER_CLEAN_HOOK and DOC_CLEAN_HOOK are similar. They should point to executables, then that executable shall be run from the temporary (top) directory of the kernel headers and documentation just before packaging respectively, so people may take any action they see fit. This also has no effect on anything other than the sources that are being packaged.

kernel_debug

This target produces a Debian package containing the debugging symbols for the modules contained in the corresponding image package. The basic idea here is to keep the space in /lib/modules/<kver> under control, since this could be on a root partition with space restrictions. Please note that if module signatures are enable in the kernel configuration the corresponding image package will not have modules with the debugging link pointing to these debugging symbol files. In order to turn on debugging links for modules in the image package you need to turn off module signatures.

kernel_headers

This target produces a Debian package containing the header files included in the Linux kernel.

kernel_manual

This target produces a Debian package containing the section 9 manual pages included in the Linux kernel. Please note that this is not really an independent target; calling this shall also invoke the kernel_doc target, and creates a kernel−doc package at the same time.

kernel_doc

This target produces a Debian package containing the documentation included in the Linux kernel. This can be called independently of the kernel_manual target, but not the other way around.

kernel_image

This target produces a Debian package of the Linux kernel source image, and any modules configured in the kernel configuration file .config. If there is no .config file in the kernel source directory, a default configuration is provided similar to the one used to create the Debian boot−floppies. If the kernel configuration file has enabled support for modules, modules will be created and installed. If module signatures are not enabled, the resulting modules will have a link to the location of the debugging symbols file for the module, usually installed by the debug package.

If the file ./debian/post−install exists, and is an executable, it is run just before the kernel image package is created. Also, please note that if there are any scripts in ./debian/image.d/ directory, run−parts shall be called on that directory just before the kernel image package is built. The location of the root of the image package being built shall be passed in the environment variable IMAGE_TOP, and the kernel version is passed in through the environment variable version for all these scripts.

Please see the documentation about hooks in kernel−img.conf(5). These hooks are variables that can be pointed by the local sysadmin to scripts that add or remove a line from the grub menu list at kernel image install and remove times. A sample script to add lines to a grub menu file is included in the directory /usr/share/doc/kernel−package/.

Apart from hook variables that the local admin may set, there are a set of directories where packages, or the local admin, may drop in script files. The directories are /etc/kernel/preinst.d/, /etc/kernel/postinst.d/, /etc/kernel/prerm.d/, /etc/kernel/postrm.d/, /etc/kernel/preinst.d/<VERSION>/, /etc/kernel/postinst.d/<VERSION>/, /etc/kernel/prerm.d/<VERSION>/, and /etc/kernel/postrm.d/<VERSION>/. If they exists, the kernel−image package shall run a run−parts program over the directory (including the versioned one), giving the version being installed or removed as an argument, in the corresponding phase of installation or removal. Before calling these scripts, the env variable STEM shall be set to the value of the −−stem argument (or the default value, linux), and the variable KERNEL_PACKAGE_VERSION shall be set to the version of the kernel−package that created the package. These scripts shall be called with two arguments, the first being the version of the kernel image, and the second argument being the location of the kernel image itself. Since debconf is in use before the script is called, this script should issue no diagnostic messages to stdout -- while the postinst does call db_stop, debconf does not restore stdout, so messages to stdout disappear.

On installation, it also offers to run the Linux loader, LILO (or alternates like loadlin, SILO, QUIK, VMELILO, ZIPL, yaboot, PALO or GRUB), creating a configuration file for supported boot loaders if needed. At that time it also offers to put the new kernel on a floppy, formatting the floppy if needed. On deletion, the package checks the version of the kernel running, and refuses to delete a running kernel. grub rates a special mention here, since grub may not need to be rerun after installing a kernel image, though an automated change to the menu list would be nice on install and removal of kernel image packages.

modules

This target allows you to build all add−on modules and packages that are very dependent on the precise kernel version they are compiled for at the same time you build your kernel image. This target expects to find the modules or packages under /usr/src/modules, and, for all such directories, changes to MODULE_LOC/x (MODULE_LOC defaults to /usr/src/modules), and runs the kdist rule in the local debian.rules file. This target should create the Debian module package(s), and may also produce a compressed tar file, and a compressed diff file, with md5sums recorded in a changes file using dpkg−genchanges. The file is signed by the same identity that would be used to sign the kernel packages. This option is used by maintainers uploading the package to the Debian archives.

modules_config

This target allows you to configure all packages under MODULE_LOC, which defaults to /usr/src/modules. This is useful if you need to manually modify some aspects of the configuration, or if you want to manually compile the add on modules. This should not be called unless you already have a ./debian directory.

modules_image

This target allows you to build all packages under MODULE_LOC, which defaults to /usr/src/modules, but does not create the source or diff files, and does not create and sign a changes file. This is the only modules related option you need if you just want to compile the add on modules image files for installation on one or more machines. Generally called in conjunction with kernel_image, especially if also using the option append_to_version (prevents spurious warnings). This should not be called unless you already have a ./debian directory.

modules_clean

This target allows you to clean all packages under MODULE_LOC, which defaults to /usr/src/modules, and this should be all that is needed to undo the effect of any of the other modules_ targets. This should not be called unless you already have a ./debian directory.

configure

This target runs configure (actually, config_target, set by −−config which defaults to oldconfig) early, so you may edit files generated by make config in the kernel source directory and not have them stomped by make−kpkg later.

libc−kheaders

This is a special target for the libc−dev maintainer, who can use it to create the headers package that libc needs. Please note that it is dangerous to create a libc−kheaders package that is different from the headers libc was compiled with; it is known to subtly break systems. Please look at /usr/share/kernel−package/README.headers for details. Creating and installing a self created libc−kheaders package may break your system unless you know what you are doing. You have been warned.

ENVIRONMENT VARIABLES

KPKG_DEBUG, if set, causes make-kpkg to spit out debugging messages about some shell functions executed internally. This is probably of not interest to anyone not debugging make−kpkg. The following variables (documented above) also affect make−kpkg: DEBIAN_REVISION_MANDATORY, APPEND_TO_VERSION, VERSION_H_OK, KPKG_ARCH, CROSS_COMPILE, KPKG_SUBARCH, KPKG_OVERLAY_DIR, ARCH_IN_NAME, INITRD, SOURCE_CLEAN_HOOK, MODULE_LOC, CONCURRENCY_LEVEL and IGNORE_UPPERCASE_VERSION.

FILES

Apart from the runtime options, the debian.rules file run by make−kpkg also looks for a per user configuration file ~/.kernel−pkg.conf. Failing that, it looks for site−wide defaults in the file /etc/kernel−pkg.conf. The default configuration allows there to be a site wide override for the full name and email address of the person responsible for maintaining the kernel packages on the site, but the /etc/kernel−pkg.conf (or ~/.kernel−pkg.conf) file is actually a Makefile snippet, and any legal make directives may be included in there. Note: Caution is urged with this file, since you can totally change the way that the make is run by suitably editing this file. Please look at /usr/share/doc/kernel−package/Problems.gz for a list of known problems while compiling kernel images. Extensive tutorial like documentation is also available in /usr/share/doc/kernel−package/README.gz and it is recommended that one read that before using this utility.

SEE ALSO

dpkg−deb(1), dpkg−source(1), make(1), Getopt::Long(3perl), kernel−img.conf(5), kernel−pkg.conf(5), The Programmers manual, The GNU Make manual, and the extensive documentation in the /usr/share/doc/kernel−package directory

AUTHOR

This manual page was written by Manoj Srivastava <srivasta [AT] debian.org>, for the Debian GNU/Linux system.