As discussed in Chapter 4, the tool that ties together kernel builds is the make program, to which you pass a target that specifies what you want to build. Chapter 4 went over the basic targets needed to build the kernel properly, but the kernel build system also has a wide range of other targets. This chapter details these targets, and what they can be used for. All of these targets are passed to the make program on the command line, and a number of them can be grouped together if desired. For example: $ make mrproper xconfig The targets are broken down into different types in the following sections. You can get a summary of most of these targets by running, within the build directory: $ make help This target prints out a lot of the common make targets that are described in the rest of this chapter. versions, kernel make utilityinformational targets make utility informational targets, make utility command-line reference, kernel build building the kernelcommand-line reference Table 10-1 shows targets that print the kernel version, based on a number of different options. They are commonly used by scripts to determine the version of the kernel being built. Target Description kernelrelease Displays the current kernel version, as determined by the build system. kernelversion Displays the current kernel version, as told by the main Makefile. This differs from the kernelrelease target in that it doesn't use any additional version information based on configuration options or localversion files. removing files from previous builds make utilityconfiguration options make utilitycleaning targets configuration options, make utility cleaning targets, make utility Table 10-2 shows targets that simply remove files from previous builds. Their use is highly recommended to make sure you don't contaminate new builds with files leftover that may have been built with different options. They differ in how much they remove; sometimes you want to keep around files you've changed. Target Description clean Removes most of the files generated by the kernel build system, but keeps the kernel configuration. mrproper Removes all of the generated files by the kernel build system, including the configuration and some various backup files. distclean Does everything mrproper does and removes some editor backup and patch leftover files. Table 10-3 shows targets that allow the kernel to be configured in a wide range of different ways. Target escription config Updates the current kernel configuration by using a line-oriented program. menuconfig Updates the current kernel configuration by using a text-based menu program. xconfig Updates the current kernel configuration by using a QT-based graphical program. gconfig Updates the current kernel configuration by using a GTK+-based graphical program. oldconfig Updates the current kernel configuration by using the current .config file and prompting for any new options that have been added to the kernel. silentoldconfig Just like oldconfig, but prints nothing to the screen except when a question needs to be answered. randconfig Generates a new kernel configuration with random answers to all of the different options. defconfig Generates a new kernel configuration with the default answer being used for all options. The default values are taken from a file located in the arch/$ARCH/defconfig file, where $ARCH refers to the specific architecture for which the kernel is being built. allmodconfig Generates a new kernel configuration in which modules are enabled whenever possible. allyesconfig Generates a new kernel configuration with all options set to yes. allnoconfig Generates a new kernel configuration with all options set to no. Note that the allyesconfig, allmodconfig, allnoconfig, and randconfig targets also take advantage of the environment variable KCONFIG_ALLCONFIG. If that variable points to a file, that file will be used as a list of configuration values that you require to be set to a specific value. In other words, the file overrides the normal behavior of the make targets. For example, if the file ˜/linux/must_be_set contains the following variables: $ cat ˜/linux/must_be_set CONFIG_SWAP=y CONFIG_DEBUG_FS=y and you enter make allnoconfig with the proper KCONFIG_ALLCONFIG environment variable in effect: $ KCONFIG_ALLCONFIG=../must_be_set make allnoconfig $ grep CONFIG_SWAP .config CONFIG_SWAP=y then the results include: $ grep CONFIG_DEBUG_FS .config CONFIG_DEBUG_FS=y This variable would not have normally been set to y otherwise. If the KCONFIG_ALLCONFIG variable is not set, the build system checks for files in the top-level build directory named: allmod.config allno.config allrandom.config allyes.config If any of those files are present, the build uses them as lists of configuration values that must be forced to the specified values. If none of those files are found, the build system finally looks for a file called all.config for a list of forced configuration values. You can use these different files to set up a known good base configuration that will always work. Then the other configuration options can be used to generate different testing configurations for the needed situation. make utilitybuild targets build targets, make utility Table 10-4 shows targets that build the kernel itself in a variety of ways. Target Description all Builds all of the different targets needed for this kernel to be able to be used. This includes both the modules and the static portion of the kernel. vmlinux Builds just the static portion of the kernel, not any loadable modules. modules Builds all of the loadable kernel modules for this configuration. modules_install Installs all of the modules into the specified location. If no location is specified with the INSTALL_MODULE_PATH environment variable, they are installed in the default root directory of the machine. dir/ Builds all of the files in the specified directory and in all subdirectories below it. dir/file.[o|i|s] Builds only the specified file. dir/file.ko Builds all of the needed files and links them together to form the specified module. tags Builds all of the needed tags that most common text editors can use while editing the source code. TAGS Builds all of the needed tags that most common text editors can use while editing the source code. cscope Builds a cscope image, useful in source tree searches, of the source tree for the architecture specified by the configuration file (not all of the kernel source files). You can also pass a number of environment variables to make that will change the build. These can be specified for almost any target, as shown in Table 10-5. Variable Value Description V 0 This tells the build system to run in a quiet manner, showing only the file that is currently being built, and not the entire command that is running in order to build that file. This is the default option for the build system. V 1 This tells the build system to operate in a verbose way, showing the full command that is being used to generate each of the specific files. O dir This tells the build system to locate all output files in the dir directory, including the kernel configuration files. This allows the kernel to be built from a read-only filesystem and have the output placed in another location. C 1 This checks all C files that are about to be built with the sparse tool, which detects common programming errors in the kernel source files. sparse can be downloaded using git from git://git.kernel.org/pub/scm/devel/sparse/sparse.git. Nightly snapshots can be found at http://www.codemonkey.org.uk/projects/git-snapshots/sparse/. More information on how to use sparse can be found in the Documentation/sparse.txt file in the kernel source tree. C 2 This forces all C files to be checked with the sparse tool, even if they did not need to be built. packaging targets, make utility make utilitypackaging targets environment variables passed to make These targets package up a built kernel into a standalone package that can be installed on a wide range of different machines, as shown in Table 10-6. Target Description rpm Builds the kernel first and then packages it up as a RPM package that can be installed. rpm-pkg Builds a source RPM package containing the base kernel. binrpm-pkg Builds a RPM package that contains a compiled kernel and modules. deb-pkg Builds a Debian package that contains the compiled kernel and modules. tar-pkg Builds a tarball that contains the compiled kernel and modules. targz-pkg Builds a gzip-compressed tarball that contains the compiled kernel and modules. tarbz2-pkg Builds a bzip2-compressed tarball that contains the compiled kernel and modules. make utilitydocumentation targets make utilityanalysis targets documentation targets, make utility debugging, kernelfinding problem code architecturesmake utility targets analysis targets, make utility Table 10-7 shows targets that build the internal kernel documentation in a variety of different formats. Target Description xmldocs Builds the kernel documentation as XML DocBook files. psdocs Builds the kernel documentation as PostScript files. pdfdocs Builds the kernel documentation as PDF files. htmldocs Builds the kernel documentation as HTML files. mandocs Builds the kernel documentation as a set of manpages, which can then be installed with the installmandocs target. Each kernel architecture has a set of specific targets unique to it. Table 10-8 shows the targets available for the 32-bit Intel architecture. make utilityarchitecture-specific targets Target Description bzImage Creates a compressed kernel image and places it in the arch/i386/boot/bzImage file. This is the default target for the i386 kernel build. install Installs the kernel image using the distribution-specific /sbin/installkernel program. Note that this does not install the kernel modules; that must be done with the modules_install target. bzdisk Creates a boot floppy image and writes it to the /dev/fd0 device. fdimage Creates a boot floppy image and places it in the file arch/i386/boot/fdimage. The mtools package must be present on your system in order for this to work properly. isoimage Creates a CD-ROM boot image and places it in the file arch/i396/boot/image.iso. The syslinux package must be present on your system in order for this to work properly. XFS_FS option wirelessNET_RADIO kernel option wirelessIEEE 802.11 option Windows systems, filesharing with Linux VT_CONSOLE option VT (virtual terminal) option virtual terminal (VT) option VIDEO_DEV option VGA_CONSOLE option USB_UHCI_HCD option USB_STORAGE option USB_SERIAL option USB_OHCI_HCD option USB_GADGET option USB_EHCI_HCD option USB (Universal Serial Bus)kernel configuration options Universal Host Controller Interface (UHCI) UHCI (Universal Host Controller Interface) timing information in printk output tape drive, SCSI System Management Bus (SMBus) synthesizers, SCSI storage devices, USB SPI (Serial Peripheral Interface) SOUND option SND_USB_AUDIO option SND option SMBus (System Management Bus) SMB (Server Message Block)SMB_FS option SMART IDE (self-monitoring, analysis, and reporting technology) SERIAL_8250 option serial portsUSB_SERIAL kernel option SELinux (Security-Enhanced Linux) self-monitoring, analysis, and reporting technology (SMART IDE) SECURITY_SELINUX option SECURITY option SCSI_SATA option SCSI_MULTI_LUN option SCSI optionskernel configuration scanners, SCSI SATA (Serial ATA)SCSI_SATA kernel option REISERFS_FS option RAIDBLK_DEV_MD kernel option radio cards (FM) QUOTA option PROFILING option PRINTK_TIME option PPPOE (PPP over Ethernet) option power management PNPBIOS option PnP (Plug and Play)kernel configuration options PHONE option parallel port options Oracle cluster filesystem (OCFS2) OPROFILE option OHCI (Open Host Controller Interface) OCFS2_FS option NOTIFY option networkingkernel configuration options NET_RADIO option NET_ETHERNET option NETDEVICES option MultiMedia Card (MMC) option MTD (Memory Technology Device) option MMC (MultiMedia Card) option media changers, SCSI MAGIC_SYSRQ option LUNs (Logical Unit Numbers) LOGO option Logical Unit Numbers (LUNs) KPROBES option kernel message (printk) output journaled filesystems JFS_FS option ISO 8802-2 (Ethernet) ISDN (Integrated Services Digital Networks) ISAPNP option I/OINPUT kernel option Integrated Services Digital Networks (ISDN) INPUT option INFINIBAND option IEEE 802.3 (Ethernet) IEEE 802.11kernel configuration option IDE (Integrated Disk Electronics)kernel configuration options IBM JFS filesystem IB (InfiniBand) support I2O (Intelligent Input/Output) I2C option HWMON option HCD (Host Controller Driver) hardware RAID hardware monitoring (HWMON option) graphics, AGP support FUSE_FS option frame buffer (FB) option FireWireIEEE 1394 option firewalling filesystemskernel configuration options FB (frame buffer) option EXT3_FS option EXT2_FS option Ethernet devicesPPPOE kernel option Ethernet devicesNET_ETHERNET kernel option errorscore system, reporting EIDE (Enhanced IDE) EHCI (Enhanced Host Controller Interface) EDAC option DVB (Digital Video Broadcasting) DRM (Direct Rendering Manager) DRI (Direct Rendering Infrastructure) DM (Device Mapper) Direct Rendering Manager (DRM) Digital Video Broadcasting (DVB) Device Mapper (DM) debugging, kernelDEBUG_KERNEL option DEBUG_FS option CPUchoosing consolesVGA_CONSOLE kernel option consolessupport on virtual terminal configuration, kerneloption reference cluster filesystem (OCFS2) CIFS (Common Internet File System) CHR_DEV_ST option CHR_DEV_SG option CHR_DEV_SCH option CD-ROMsCD writers, SCSI boot processLOGO option BLK_DEV_SR option BLK_DEV_SD option BLK_DEV_MD option BLK_DEV_IDEFLOPPY option BLK_DEV_IDEDISK option BLK_DEV_IDECD option BLK_DEV_IDE option BLK_DEV_DM option automounter tools AUTOFS_FS option ATAPI (ATA Packet Interface) ATA (AT Attachment) Accelerated Graphics Port (AGP) 802.11kernel configuration option Table 10-9 shows targets that are good for trying to find problem code in the kernel. It's a good idea to create a stack space list when creating new code to determine that your changes are not taking up too much kernel stack space. The namespacecheck target is useful for determining whether your changes can safely add its symbols to the kernel's global namespace. Target Description checkstack Generate a list of the functions that use the most of the kernel stack space. namespacecheck Generate a list of all of the kernel symbols and their namespaces. This will be a large list.