Overview of Kbuild Commands 24 January 1999 Michael Elizabeth Chastain, === Introduction Someday we'll get our arms around all this stuff and clean it up a little! Meanwhile, this file describes the system as it is today. === Quick Start If you are building a kernel for the first time, here are the commands you need: make config make dep make bzImage Instead of 'make config', you can run 'make menuconfig' for a full-screen text interface, or 'make xconfig' for an X interface using TCL/TK. 'make bzImage' will leave your new kernel image in arch/i386/boot/bzImage. You can also use 'make bzdisk' or 'make bzlilo'. See the lilo documentation for more information on how to use lilo. You can also use the 'loadlin' program to boot Linux from MS-DOS. Some computers won't work with 'make bzImage', either due to hardware problems or very old versions of lilo or loadlin. If your kernel image is small, you may use 'make zImage', 'make zdisk', or 'make zlilo' on theses systems. If you find a file name 'vmlinux' in the top directory of the source tree, just ignore it. This is an intermediate file and you can't boot from it. Other architectures: the information above is oriented towards the i386. On other architectures, there are no 'bzImage' files; simply use 'zImage' or 'vmlinux' as appropriate for your architecture. Note: the difference between 'zImage' files and 'bzImage' files is that 'bzImage' uses a different layout and a different loading algorithm, and thus has a larger capacity. Both files use gzip compression. The 'bz' in 'bzImage' stands for 'big zImage', not for 'bzip'! === Top Level Makefile targets Here are the targets available at the top level: make config, make oldconfig, make menuconfig, make xconfig Configure the Linux kernel. You must do this before almost anything else. config line-oriented interface oldconfig line-oriented interface, re-uses old values menuconfig curses-based full-screen interface xconfig X window system interface make checkconfig This runs a little perl script that checks the source tree for missing instances of #include . Someone needs to do this occasionally, because the C preprocessor will silently give bad results if these symbols haven't been included (it treats undefined symbols in preprocessor directives as defined to 0). Superfluous uses of #include are also reported, but you can ignore these, because smart CONFIG_* dependencies make them harmless. You can run 'make checkconfig' without configuring the kernel. Also, 'make checkconfig' does not modify any files. make checkhelp This runs another little perl script that checks the source tree for options that are in Config.in files but are not documented in scripts/Configure.help. Again, someone needs to do this occasionally. If you are adding configuration options, it's nice if you do it before you publish your patch! You can run 'make checkhelp' without configuring the kernel. Also, 'make checkhelp' does not modify any files. make dep, make depend 'make dep' is a synonym for the long form, 'make depend'. This command does two things. First, it computes dependency information about which .o files depend on which .h files. It records this information in a top-level file named .hdepend and in one file per source directory named .depend. Second, if you have CONFIG_MODVERSIONS enabled, 'make dep' computes symbol version information for all of the files that export symbols (note that both resident and modular files may export symbols). If you do not enable CONFIG_MODVERSIONS, you only have to run 'make dep' once, right after the first time you configure the kernel. The .hdepend files and the .depend file are independent of your configuration. If you do enable CONFIG_MODVERSIONS, you must run 'make dep' every time you change your configuration, because the module symbol version information depends on the configuration. [to be continued ...]