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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | VERY QUICK AND DIRTY README by Lars Wirzenius This is the README for the Linux kernel sources. It tells a few small things about kernel configuration and other things that can perhaps be useful if you want to compile the kernel from scratch. It leaves out a lot as well, probably because the person who wrote it doesn't understand very much about operating systems. Linus did his best to help, but all problems this causes are my fault. In order to compile this version of the kernel you need GCC 2.2.2 or newer. Some makefile targets require special commands which may not be available on all machines (see below). Normal utilities like ls etc are not explicitly listed, they are assumed to be available on all systems. Kernel sources are usually kept in /usr/src/linux. If you have them elsewhere, you will have to change path names in a few places. Filenames that aren't absolute are supposed to be relative to the toplevel kernel source directory. * Basic configuration 1. Edit Makefile: Check the definitions of macros ROOTDEV, KEYBOARD, MATH_EMULATION, RAMDISK and SVGA_MODE before you run make. They are explained in the Makefile. MATH_EMULATION does not hurt much even if you have an FPU (387 or a 486 with a built in FPU), since Linux uses the FPU if it finds one, even with MATH_EMULATION defined. The kernel will be slightly bigger. It is probably not worth it to recompile the kernel just to get rid of the emulation. [ Linus' note1: if you have a correctly installed gcc-2.2.2d, you can also remove the "-nostdinc -I$(KERNELHDRS)" thing from the main Makefile CC definition. But it doesn't hurt to have it, as long as KERNELHDRS is correctly defined ] 2. Create a symlink: ln -s /usr/src/linux/include/linux /usr/include/linux This is required so that tools/build.c will compile and link (it requires the standard versions of headers instead of the kernel specific headers, as it is a normal application, not kernel code). [ Linus' note2: This is automatically done by the gcc-2.2.2d installation script, so if you have the new compiler, you should already have this link ] * Things you may want to get rid of 3. To remove SCSI drivers, do this: - remove kernel/blk_drv/scsi/scsi.a from DRIVERS in the Makefile - remove the commands for the subdirs dependency in kernel/blk_drv/Makefile - add "#undef CONFIG_SCSI" to the end of include/linux/config.h The SCSI drivers take a bit of memory, and also slow the bootup a bit, so you may want to get rid of them if you don't have an SCSI drive. 4. The kernel contains code for the extended filesystem (extfs), MS-DOS filesystem (dosfs) and proc-fs (proc), all of which are in testing phases and are not recommended for real use yet. If you don't want to include these in the kernel, do the following: - remove references to these in the FILESYSTEMS macro in the root Makefile - remove directory names from the SUBDIRS macro in fs/Makefile - remove the corresponding lines in the initialization of file_systems in fs/super.c. 5. To configure more ptys do this: - change NR_PTYS in include/linux/tty.h to the number you want - create the new files in /dev - recompile the kernel * Running make [ Linus' note3: if you have problems with make not working correctly, get a new copy of GNU make. pmake may or may not work due to the macro inheritation assumptions etc ] Unless you know what you're doing, don't ever run the makefiles in subdirectories by hand. There is a bit of interaction between the various makefiles, e.g. in the form of inherited macros and the like. The following targets all apply for the makefile at the root of the kernel source tree. "make" or "make all" compiles everything. "make Image" is like "make all", but it doesn't bump the number in .version, which tells how many times this version has been compiled (helps you differentiate between different configurations etc). "make disk" is like "make Image", but it additionally writes out a copy of the boot image to a floppy in your first floppy drive (/dev/fd0; change the filename if you want a different floppy). You need to have a formatted, overwritable floppy in that drive when it is time to do the copy. This requires dd. "make dep" updates all dependencies. This requires sed. It modifies the makefiles directly (the end of them, starting at the ###Dependencies -line at the end). "make clean" will remove all object files and other files created by the compilation. This requires basename. You may wish to redirect compiler error messages to a file so that you can review them later and to ease problem fixing. You can do this with Bash with: make something 2>&1 | tee make.out The tee part is so that you can check what is going on while the compilation runs. If you have GNU emacs and use M-x compile you don't need this, of course. Lars Wirzeniu |