- Linux kernel release 2.6.xx <http://kernel.org>
+ Linux kernel release 3.x <http://kernel.org/>
-These are the release notes for Linux version 2.6. Read them carefully,
+These are the release notes for Linux version 3. 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.
Although originally developed first for 32-bit x86-based PCs (386 or higher),
today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
- UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH,
+ UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
- and Renesas M32R architectures.
+ Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures.
Linux is easily portable to most general-purpose 32- or 64-bit architectures
as long as they have a paged memory management unit (PMMU) and a port of the
GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
also been ported to a number of architectures without a PMMU, although
functionality is then obviously somewhat limited.
+ Linux has also been ported to itself. You can now run the kernel as a
+ userspace application - this is called UserMode Linux (UML).
DOCUMENTATION:
- 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.
+ number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
+ After installation, "make psdocs", "make pdfdocs", "make htmldocs",
+ or "make mandocs" will render the documentation in the requested format.
-INSTALLING the kernel:
+INSTALLING the kernel source:
- 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 -
+ gzip -cd linux-3.X.tar.gz | tar xvf -
or
- bzip2 -dc linux-2.6.XX.tar.bz2 | tar xvf -
+ bzip2 -dc linux-3.X.tar.bz2 | tar xvf -
Replace "XX" with the version number of the latest kernel.
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
+ - You can also upgrade between 3.x releases by patching. Patches are
distributed in the traditional gzip and the newer 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:
+ top level directory of the kernel source (linux-3.x) and execute:
- gzip -cd ../patch-2.6.xx.gz | patch -p1
+ gzip -cd ../patch-3.x.gz | patch -p1
or
- bzip2 -dc ../patch-2.6.xx.bz2 | patch -p1
+ bzip2 -dc ../patch-3.x.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
failed patches (xxx# or xxx.rej). If there are, either you or me has
made a mistake.
- Unlike patches for the 2.6.x kernels, patches for the 2.6.x.y kernels
+ Unlike patches for the 3.x kernels, patches for the 3.x.y kernels
(also known as the -stable kernels) are not incremental but instead apply
- directly to the base 2.6.x kernel. Please read
+ directly to the base 3.x kernel. Please read
Documentation/applying-patches.txt for more information.
Alternatively, the script patch-kernel can be used to automate this
an alternative directory can be specified as the second argument.
- If you are upgrading between releases using the stable series patches
- (for example, patch-2.6.xx.y), note that these "dot-releases" are
- not incremental and must be applied to the 2.6.xx base tree. For
- example, if your base kernel is 2.6.12 and you want to apply the
- 2.6.12.3 patch, you do not and indeed must not first apply the
- 2.6.12.1 and 2.6.12.2 patches. Similarly, if you are running kernel
- version 2.6.12.2 and want to jump to 2.6.12.3, you must first
- reverse the 2.6.12.2 patch (that is, patch -R) _before_ applying
- the 2.6.12.3 patch.
+ (for example, patch-3.x.y), note that these "dot-releases" are
+ not incremental and must be applied to the 3.x base tree. For
+ example, if your base kernel is 3.0 and you want to apply the
+ 3.0.3 patch, you do not and indeed must not first apply the
+ 3.0.1 and 3.0.2 patches. Similarly, if you are running kernel
+ version 3.0.2 and want to jump to 3.0.3, you must first
+ reverse the 3.0.2 patch (that is, patch -R) _before_ applying
+ the 3.0.3 patch.
+ You can read more on this in Documentation/applying-patches.txt
- Make sure you have no stale .o files and dependencies lying around:
SOFTWARE REQUIREMENTS
- Compiling and running the 2.6.xx kernels requires up-to-date
+ Compiling and running the 3.x 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
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
+ kernel source code: /usr/src/linux-3.N
build directory: /home/name/build/kernel
To configure and build the kernel use:
- cd /usr/src/linux-2.6.N
+ cd /usr/src/linux-3.N
make O=/home/name/build/kernel menuconfig
make O=/home/name/build/kernel
sudo make O=/home/name/build/kernel modules_install install
only ask you for the answers to new questions.
- Alternate configuration commands are:
+ "make config" Plain text interface.
"make menuconfig" Text based color menus, radiolists & dialogs.
+ "make nconfig" Enhanced text based color menus.
"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
"make silentoldconfig"
Like above, but avoids cluttering the screen
with questions already answered.
+ Additionally updates the dependencies.
"make defconfig" Create a ./.config file by using the default
- symbol values from arch/$ARCH/defconfig.
+ symbol values from either arch/$ARCH/defconfig
+ or arch/$ARCH/configs/${PLATFORM}_defconfig,
+ depending on the architecture.
+ "make ${PLATFORM}_defconfig"
+ Create a ./.config file by using the default
+ symbol values from
+ arch/$ARCH/configs/${PLATFORM}_defconfig.
+ Use "make help" to get a list of all available
+ platforms of your architecture.
"make allyesconfig"
Create a ./.config file by setting symbol
values to 'y' as much as possible.
"make randconfig" Create a ./.config file by setting symbol
values to random values.
- The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
- also use the environment variable KCONFIG_ALLCONFIG to specify a
- filename that contains config options that the user requires to be
- set to a specific value. If KCONFIG_ALLCONFIG=filename is not used,
- "make *config" checks for a file named "all{yes/mod/no/random}.config"
- for symbol values that are to be forced. If this file is not found,
- it checks for a file named "all.config" to contain forced values.
-
+ You can find more information on using the Linux kernel config tools
+ in Documentation/kbuild/kconfig.txt.
+
NOTES on "make config":
- having unnecessary drivers will make the kernel bigger, and can
under some circumstances lead to problems: probing for a
- If you configured any of the parts of the kernel as `modules', you
will also have to do "make modules_install".
+ - Verbose kernel compile/build output:
+
+ Normally the kernel build system runs in a fairly quiet mode (but not
+ totally silent). However, sometimes you or other kernel developers need
+ to see compile, link, or other commands exactly as they are executed.
+ For this, use "verbose" build mode. This is done by inserting
+ "V=1" in the "make" command. E.g.:
+
+ make V=1 all
+
+ To have the build system also tell the reason for the rebuild of each
+ target, use "V=2". The default is "V=0".
+
- 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
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.
+ them to me (torvalds@linux-foundation.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
- 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.
+ sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
+ 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
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.
+ possible will help. Please read the REPORTING-BUGS document for details.
- 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