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diff --git a/README b/README new file mode 100644 index 00000000000..0df20f07227 --- /dev/null +++ b/README @@ -0,0 +1,305 @@ + Linux kernel release 2.6.xx + +These are the release notes for Linux version 2.6. Read them carefully, +as they tell you what this is all about, explain how to install the +kernel, and what to do if something goes wrong. + +WHAT IS LINUX? + + Linux is a Unix clone written from scratch by Linus Torvalds with + assistance from a loosely-knit team of hackers across the Net. + It aims towards POSIX compliance. + + It has all the features you would expect in a modern fully-fledged + Unix, including true multitasking, virtual memory, shared libraries, + demand loading, shared copy-on-write executables, proper memory + management and TCP/IP networking. + + It is distributed under the GNU General Public License - see the + accompanying COPYING file for more details. + +ON WHAT HARDWARE DOES IT RUN? + + Linux was first developed for 386/486-based PCs. These days it also + runs on ARMs, DEC Alphas, SUN Sparcs, M68000 machines (like Atari and + Amiga), MIPS and PowerPC, and others. + +DOCUMENTATION: + + - There is a lot of documentation available both in electronic form on + the Internet and in books, both Linux-specific and pertaining to + general UNIX questions. I'd recommend looking into the documentation + subdirectories on any Linux FTP site for the LDP (Linux Documentation + Project) books. This README is not meant to be documentation on the + system: there are much better sources available. + + - There are various README files in the Documentation/ subdirectory: + these typically contain kernel-specific installation notes for some + drivers for example. See Documentation/00-INDEX for a list of what + is contained in each file. Please read the Changes file, as it + contains information about the problems, which may result by upgrading + your kernel. + + - The Documentation/DocBook/ subdirectory contains several guides for + kernel developers and users. These guides can be rendered in a + number of formats: PostScript (.ps), PDF, and HTML, among others. + After installation, "make psdocs", "make pdfdocs", or "make htmldocs" + will render the documentation in the requested format. + +INSTALLING the kernel: + + - If you install the full sources, put the kernel tarball in a + directory where you have permissions (eg. your home directory) and + unpack it: + + gzip -cd linux-2.6.XX.tar.gz | tar xvf - + + Replace "XX" with the version number of the latest kernel. + + Do NOT use the /usr/src/linux area! This area has a (usually + incomplete) set of kernel headers that are used by the library header + files. They should match the library, and not get messed up by + whatever the kernel-du-jour happens to be. + + - You can also upgrade between 2.6.xx releases by patching. Patches are + distributed in the traditional gzip and the new bzip2 format. To + install by patching, get all the newer patch files, enter the + top level directory of the kernel source (linux-2.6.xx) and execute: + + gzip -cd ../patch-2.6.xx.gz | patch -p1 + + or + bzip2 -dc ../patch-2.6.xx.bz2 | patch -p1 + + (repeat xx for all versions bigger than the version of your current + source tree, _in_order_) and you should be ok. You may want to remove + the backup files (xxx~ or xxx.orig), and make sure that there are no + failed patches (xxx# or xxx.rej). If there are, either you or me has + made a mistake. + + Alternatively, the script patch-kernel can be used to automate this + process. It determines the current kernel version and applies any + patches found. + + linux/scripts/patch-kernel linux + + The first argument in the command above is the location of the + kernel source. Patches are applied from the current directory, but + an alternative directory can be specified as the second argument. + + - Make sure you have no stale .o files and dependencies lying around: + + cd linux + make mrproper + + You should now have the sources correctly installed. + +SOFTWARE REQUIREMENTS + + Compiling and running the 2.6.xx kernels requires up-to-date + versions of various software packages. Consult + Documentation/Changes for the minimum version numbers required + and how to get updates for these packages. Beware that using + excessively old versions of these packages can cause indirect + errors that are very difficult to track down, so don't assume that + you can just update packages when obvious problems arise during + build or operation. + +BUILD directory for the kernel: + + When compiling the kernel all output files will per default be + stored together with the kernel source code. + Using the option "make O=output/dir" allow you to specify an alternate + place for the output files (including .config). + Example: + kernel source code: /usr/src/linux-2.6.N + build directory: /home/name/build/kernel + + To configure and build the kernel use: + cd /usr/src/linux-2.6.N + make O=/home/name/build/kernel menuconfig + make O=/home/name/build/kernel + sudo make O=/home/name/build/kernel modules_install install + + Please note: If the 'O=output/dir' option is used then it must be + used for all invocations of make. + +CONFIGURING the kernel: + + Do not skip this step even if you are only upgrading one minor + version. New configuration options are added in each release, and + odd problems will turn up if the configuration files are not set up + as expected. If you want to carry your existing configuration to a + new version with minimal work, use "make oldconfig", which will + only ask you for the answers to new questions. + + - Alternate configuration commands are: + "make menuconfig" Text based color menus, radiolists & dialogs. + "make xconfig" X windows (Qt) based configuration tool. + "make gconfig" X windows (Gtk) based configuration tool. + "make oldconfig" Default all questions based on the contents of + your existing ./.config file. + + NOTES on "make config": + - having unnecessary drivers will make the kernel bigger, and can + under some circumstances lead to problems: probing for a + nonexistent controller card may confuse your other controllers + - compiling the kernel with "Processor type" set higher than 386 + will result in a kernel that does NOT work on a 386. The + kernel will detect this on bootup, and give up. + - A kernel with math-emulation compiled in will still use the + coprocessor if one is present: the math emulation will just + never get used in that case. The kernel will be slightly larger, + but will work on different machines regardless of whether they + have a math coprocessor or not. + - the "kernel hacking" configuration details usually result in a + bigger or slower kernel (or both), and can even make the kernel + less stable by configuring some routines to actively try to + break bad code to find kernel problems (kmalloc()). Thus you + should probably answer 'n' to the questions for + "development", "experimental", or "debugging" features. + + - Check the top Makefile for further site-dependent configuration + (default SVGA mode etc). + +COMPILING the kernel: + + - Make sure you have gcc 2.95.3 available. + gcc 2.91.66 (egcs-1.1.2), and gcc 2.7.2.3 are known to miscompile + some parts of the kernel, and are *no longer supported*. + Also remember to upgrade your binutils package (for as/ld/nm and company) + if necessary. For more information, refer to Documentation/Changes. + + Please note that you can still run a.out user programs with this kernel. + + - Do a "make" to create a compressed kernel image. It is also + possible to do "make install" if you have lilo installed to suit the + kernel makefiles, but you may want to check your particular lilo setup first. + + To do the actual install you have to be root, but none of the normal + build should require that. Don't take the name of root in vain. + + - If you configured any of the parts of the kernel as `modules', you + will also have to do "make modules_install". + + - Keep a backup kernel handy in case something goes wrong. This is + especially true for the development releases, since each new release + contains new code which has not been debugged. Make sure you keep a + backup of the modules corresponding to that kernel, as well. If you + are installing a new kernel with the same version number as your + working kernel, make a backup of your modules directory before you + do a "make modules_install". + + - In order to boot your new kernel, you'll need to copy the kernel + image (e.g. .../linux/arch/i386/boot/bzImage after compilation) + to the place where your regular bootable kernel is found. + + - Booting a kernel directly from a floppy without the assistance of a + bootloader such as LILO, is no longer supported. + + If you boot Linux from the hard drive, chances are you use LILO which + uses the kernel image as specified in the file /etc/lilo.conf. The + kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or + /boot/bzImage. To use the new kernel, save a copy of the old image + and copy the new image over the old one. Then, you MUST RERUN LILO + to update the loading map!! If you don't, you won't be able to boot + the new kernel image. + + Reinstalling LILO is usually a matter of running /sbin/lilo. + You may wish to edit /etc/lilo.conf to specify an entry for your + old kernel image (say, /vmlinux.old) in case the new one does not + work. See the LILO docs for more information. + + After reinstalling LILO, you should be all set. Shutdown the system, + reboot, and enjoy! + + If you ever need to change the default root device, video mode, + ramdisk size, etc. in the kernel image, use the 'rdev' program (or + alternatively the LILO boot options when appropriate). No need to + recompile the kernel to change these parameters. + + - Reboot with the new kernel and enjoy. + +IF SOMETHING GOES WRONG: + + - If you have problems that seem to be due to kernel bugs, please check + the file MAINTAINERS to see if there is a particular person associated + with the part of the kernel that you are having trouble with. If there + isn't anyone listed there, then the second best thing is to mail + them to me (torvalds@osdl.org), and possibly to any other relevant + mailing-list or to the newsgroup. + + - In all bug-reports, *please* tell what kernel you are talking about, + how to duplicate the problem, and what your setup is (use your common + sense). If the problem is new, tell me so, and if the problem is + old, please try to tell me when you first noticed it. + + - If the bug results in a message like + + unable to handle kernel paging request at address C0000010 + Oops: 0002 + EIP: 0010:XXXXXXXX + eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx + esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx + ds: xxxx es: xxxx fs: xxxx gs: xxxx + Pid: xx, process nr: xx + xx xx xx xx xx xx xx xx xx xx + + or similar kernel debugging information on your screen or in your + system log, please duplicate it *exactly*. The dump may look + incomprehensible to you, but it does contain information that may + help debugging the problem. The text above the dump is also + important: it tells something about why the kernel dumped code (in + the above example it's due to a bad kernel pointer). More information + on making sense of the dump is in Documentation/oops-tracing.txt + + - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump + as is, otherwise you will have to use the "ksymoops" program to make + sense of the dump. This utility can be downloaded from + ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops. + Alternately you can do the dump lookup by hand: + + - In debugging dumps like the above, it helps enormously if you can + look up what the EIP value means. The hex value as such doesn't help + me or anybody else very much: it will depend on your particular + kernel setup. What you should do is take the hex value from the EIP + line (ignore the "0010:"), and look it up in the kernel namelist to + see which kernel function contains the offending address. + + To find out the kernel function name, you'll need to find the system + binary associated with the kernel that exhibited the symptom. This is + the file 'linux/vmlinux'. To extract the namelist and match it against + the EIP from the kernel crash, do: + + nm vmlinux | sort | less + + This will give you a list of kernel addresses sorted in ascending + order, from which it is simple to find the function that contains the + offending address. Note that the address given by the kernel + debugging messages will not necessarily match exactly with the + function addresses (in fact, that is very unlikely), so you can't + just 'grep' the list: the list will, however, give you the starting + point of each kernel function, so by looking for the function that + has a starting address lower than the one you are searching for but + is followed by a function with a higher address you will find the one + you want. In fact, it may be a good idea to include a bit of + "context" in your problem report, giving a few lines around the + interesting one. + + If you for some reason cannot do the above (you have a pre-compiled + kernel image or similar), telling me as much about your setup as + possible will help. + + - Alternately, you can use gdb on a running kernel. (read-only; i.e. you + cannot change values or set break points.) To do this, first compile the + kernel with -g; edit arch/i386/Makefile appropriately, then do a "make + clean". You'll also need to enable CONFIG_PROC_FS (via "make config"). + + After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore". + You can now use all the usual gdb commands. The command to look up the + point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes + with the EIP value.) + + gdb'ing a non-running kernel currently fails because gdb (wrongly) + disregards the starting offset for which the kernel is compiled. + |