1 GNU Linux-libre <http://linux-libre.fsfla.org>
3 These are the release notes for GNU Linux-libre Read them carefully,
4 as they tell you what this is all about, explain how to install the
5 kernel, and what to do if something goes wrong.
7 WHAT IS GNU Linux-libre?
9 GNU Linux-libre is a Free version of the kernel Linux (see below),
10 suitable for use with the GNU Operating System in 100% Free
11 GNU/Linux-libre System Distributions.
12 http://www.gnu.org/distros/
14 It removes non-Free components from Linux, that are disguised as
15 source code or distributed in separate files. It also disables
16 run-time requests for non-Free components, shipped separately or as
17 part of Linux, and documentation pointing to them, so as to avoid
18 (Free-)baiting users into the trap of non-Free Software.
19 http://www.fsfla.org/anuncio/2010-11-Linux-2.6.36-libre-debait
21 Linux-libre started within the gNewSense GNU/Linux distribution.
22 It was later adopted by Jeff Moe, who coined its name, and in 2008
23 it became a project maintained by FSF Latin America. In 2012, it
24 became part of the GNU Project.
26 The GNU Linux-libre project takes a minimal-changes approach to
27 cleaning up Linux, making no effort to substitute components that
28 need to be removed with functionally equivalent Free ones.
29 Nevertheless, we encourage and support efforts towards doing so.
30 http://libreplanet.org/wiki/LinuxLibre:Devices_that_require_non-free_firmware
32 Our mascot is Freedo, a light-blue penguin that has just come out
33 of the shower. Although we like penguins, GNU is a much greater
34 contribution to the entire system, so its mascot deserves more
35 promotion. See our web page for their images.
36 http://linux-libre.fsfla.org/
40 Linux is a clone of the Unix kernel, written from scratch by
41 Linus Torvalds with assistance from a loosely-knit team of hackers across
42 the Net. It aims towards POSIX and Single UNIX Specification compliance.
44 It has all the features you would expect in a modern fully-fledged Unix kernel,
45 including true multitasking, virtual memory, shared libraries, demand
46 loading, shared copy-on-write executables, proper memory management,
47 and multistack networking including IPv4 and IPv6.
49 It is distributed under the GNU General Public License - see the
50 accompanying COPYING file for more details.
52 ON WHAT HARDWARE DOES IT RUN?
54 Although originally developed first for 32-bit x86-based PCs (386 or higher),
55 today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
56 UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
57 IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
58 Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures.
60 Linux is easily portable to most general-purpose 32- or 64-bit architectures
61 as long as they have a paged memory management unit (PMMU) and a port of the
62 GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
63 also been ported to a number of architectures without a PMMU, although
64 functionality is then obviously somewhat limited.
65 Linux has also been ported to itself. You can now run the kernel as a
66 userspace application - this is called UserMode Linux (UML).
70 - There is a lot of documentation available both in electronic form on
71 the Internet and in books, both Linux-specific and pertaining to
72 general UNIX questions. I'd recommend looking into the documentation
73 subdirectories on any Linux FTP site for the LDP (Linux Documentation
74 Project) books. This README is not meant to be documentation on the
75 system: there are much better sources available.
77 - There are various README files in the Documentation/ subdirectory:
78 these typically contain kernel-specific installation notes for some
79 drivers for example. See Documentation/00-INDEX for a list of what
80 is contained in each file. Please read the Changes file, as it
81 contains information about the problems, which may result by upgrading
84 - The Documentation/DocBook/ subdirectory contains several guides for
85 kernel developers and users. These guides can be rendered in a
86 number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
87 After installation, "make psdocs", "make pdfdocs", "make htmldocs",
88 or "make mandocs" will render the documentation in the requested format.
90 INSTALLING the kernel source:
92 - If you install the full sources, put the kernel tarball in a
93 directory where you have permissions (eg. your home directory) and
96 gzip -cd linux-3.X.tar.gz | tar xvf -
99 bzip2 -dc linux-3.X.tar.bz2 | tar xvf -
102 Replace "XX" with the version number of the latest kernel.
104 Do NOT use the /usr/src/linux area! This area has a (usually
105 incomplete) set of kernel headers that are used by the library header
106 files. They should match the library, and not get messed up by
107 whatever the kernel-du-jour happens to be.
109 - You can also upgrade between 3.x releases by patching. Patches are
110 distributed in the traditional gzip and the newer bzip2 format. To
111 install by patching, get all the newer patch files, enter the
112 top level directory of the kernel source (linux-3.x) and execute:
114 gzip -cd ../patch-3.x.gz | patch -p1
117 bzip2 -dc ../patch-3.x.bz2 | patch -p1
119 (repeat xx for all versions bigger than the version of your current
120 source tree, _in_order_) and you should be ok. You may want to remove
121 the backup files (xxx~ or xxx.orig), and make sure that there are no
122 failed patches (xxx# or xxx.rej). If there are, either you or me has
125 Unlike patches for the 3.x kernels, patches for the 3.x.y kernels
126 (also known as the -stable kernels) are not incremental but instead apply
127 directly to the base 3.x kernel. Please read
128 Documentation/applying-patches.txt for more information.
130 Alternatively, the script patch-kernel can be used to automate this
131 process. It determines the current kernel version and applies any
134 linux/scripts/patch-kernel linux
136 The first argument in the command above is the location of the
137 kernel source. Patches are applied from the current directory, but
138 an alternative directory can be specified as the second argument.
140 - If you are upgrading between releases using the stable series patches
141 (for example, patch-3.x.y), note that these "dot-releases" are
142 not incremental and must be applied to the 3.x base tree. For
143 example, if your base kernel is 3.0 and you want to apply the
144 3.0.3 patch, you do not and indeed must not first apply the
145 3.0.1 and 3.0.2 patches. Similarly, if you are running kernel
146 version 3.0.2 and want to jump to 3.0.3, you must first
147 reverse the 3.0.2 patch (that is, patch -R) _before_ applying
149 You can read more on this in Documentation/applying-patches.txt
151 - Make sure you have no stale .o files and dependencies lying around:
156 You should now have the sources correctly installed.
158 SOFTWARE REQUIREMENTS
160 Compiling and running the 3.x kernels requires up-to-date
161 versions of various software packages. Consult
162 Documentation/Changes for the minimum version numbers required
163 and how to get updates for these packages. Beware that using
164 excessively old versions of these packages can cause indirect
165 errors that are very difficult to track down, so don't assume that
166 you can just update packages when obvious problems arise during
169 BUILD directory for the kernel:
171 When compiling the kernel all output files will per default be
172 stored together with the kernel source code.
173 Using the option "make O=output/dir" allow you to specify an alternate
174 place for the output files (including .config).
176 kernel source code: /usr/src/linux-3.N
177 build directory: /home/name/build/kernel
179 To configure and build the kernel use:
180 cd /usr/src/linux-3.N
181 make O=/home/name/build/kernel menuconfig
182 make O=/home/name/build/kernel
183 sudo make O=/home/name/build/kernel modules_install install
185 Please note: If the 'O=output/dir' option is used then it must be
186 used for all invocations of make.
188 CONFIGURING the kernel:
190 Do not skip this step even if you are only upgrading one minor
191 version. New configuration options are added in each release, and
192 odd problems will turn up if the configuration files are not set up
193 as expected. If you want to carry your existing configuration to a
194 new version with minimal work, use "make oldconfig", which will
195 only ask you for the answers to new questions.
197 - Alternate configuration commands are:
198 "make config" Plain text interface.
199 "make menuconfig" Text based color menus, radiolists & dialogs.
200 "make nconfig" Enhanced text based color menus.
201 "make xconfig" X windows (Qt) based configuration tool.
202 "make gconfig" X windows (Gtk) based configuration tool.
203 "make oldconfig" Default all questions based on the contents of
204 your existing ./.config file and asking about
206 "make silentoldconfig"
207 Like above, but avoids cluttering the screen
208 with questions already answered.
209 Additionally updates the dependencies.
210 "make defconfig" Create a ./.config file by using the default
211 symbol values from either arch/$ARCH/defconfig
212 or arch/$ARCH/configs/${PLATFORM}_defconfig,
213 depending on the architecture.
214 "make ${PLATFORM}_defconfig"
215 Create a ./.config file by using the default
217 arch/$ARCH/configs/${PLATFORM}_defconfig.
218 Use "make help" to get a list of all available
219 platforms of your architecture.
221 Create a ./.config file by setting symbol
222 values to 'y' as much as possible.
224 Create a ./.config file by setting symbol
225 values to 'm' as much as possible.
226 "make allnoconfig" Create a ./.config file by setting symbol
227 values to 'n' as much as possible.
228 "make randconfig" Create a ./.config file by setting symbol
229 values to random values.
231 You can find more information on using the Linux kernel config tools
232 in Documentation/kbuild/kconfig.txt.
234 NOTES on "make config":
235 - having unnecessary drivers will make the kernel bigger, and can
236 under some circumstances lead to problems: probing for a
237 nonexistent controller card may confuse your other controllers
238 - compiling the kernel with "Processor type" set higher than 386
239 will result in a kernel that does NOT work on a 386. The
240 kernel will detect this on bootup, and give up.
241 - A kernel with math-emulation compiled in will still use the
242 coprocessor if one is present: the math emulation will just
243 never get used in that case. The kernel will be slightly larger,
244 but will work on different machines regardless of whether they
245 have a math coprocessor or not.
246 - the "kernel hacking" configuration details usually result in a
247 bigger or slower kernel (or both), and can even make the kernel
248 less stable by configuring some routines to actively try to
249 break bad code to find kernel problems (kmalloc()). Thus you
250 should probably answer 'n' to the questions for
251 "development", "experimental", or "debugging" features.
253 COMPILING the kernel:
255 - Make sure you have at least gcc 3.2 available.
256 For more information, refer to Documentation/Changes.
258 Please note that you can still run a.out user programs with this kernel.
260 - Do a "make" to create a compressed kernel image. It is also
261 possible to do "make install" if you have lilo installed to suit the
262 kernel makefiles, but you may want to check your particular lilo setup first.
264 To do the actual install you have to be root, but none of the normal
265 build should require that. Don't take the name of root in vain.
267 - If you configured any of the parts of the kernel as `modules', you
268 will also have to do "make modules_install".
270 - Verbose kernel compile/build output:
272 Normally the kernel build system runs in a fairly quiet mode (but not
273 totally silent). However, sometimes you or other kernel developers need
274 to see compile, link, or other commands exactly as they are executed.
275 For this, use "verbose" build mode. This is done by inserting
276 "V=1" in the "make" command. E.g.:
280 To have the build system also tell the reason for the rebuild of each
281 target, use "V=2". The default is "V=0".
283 - Keep a backup kernel handy in case something goes wrong. This is
284 especially true for the development releases, since each new release
285 contains new code which has not been debugged. Make sure you keep a
286 backup of the modules corresponding to that kernel, as well. If you
287 are installing a new kernel with the same version number as your
288 working kernel, make a backup of your modules directory before you
289 do a "make modules_install".
290 Alternatively, before compiling, use the kernel config option
291 "LOCALVERSION" to append a unique suffix to the regular kernel version.
292 LOCALVERSION can be set in the "General Setup" menu.
294 - In order to boot your new kernel, you'll need to copy the kernel
295 image (e.g. .../linux/arch/i386/boot/bzImage after compilation)
296 to the place where your regular bootable kernel is found.
298 - Booting a kernel directly from a floppy without the assistance of a
299 bootloader such as LILO, is no longer supported.
301 If you boot Linux from the hard drive, chances are you use LILO which
302 uses the kernel image as specified in the file /etc/lilo.conf. The
303 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
304 /boot/bzImage. To use the new kernel, save a copy of the old image
305 and copy the new image over the old one. Then, you MUST RERUN LILO
306 to update the loading map!! If you don't, you won't be able to boot
307 the new kernel image.
309 Reinstalling LILO is usually a matter of running /sbin/lilo.
310 You may wish to edit /etc/lilo.conf to specify an entry for your
311 old kernel image (say, /vmlinux.old) in case the new one does not
312 work. See the LILO docs for more information.
314 After reinstalling LILO, you should be all set. Shutdown the system,
317 If you ever need to change the default root device, video mode,
318 ramdisk size, etc. in the kernel image, use the 'rdev' program (or
319 alternatively the LILO boot options when appropriate). No need to
320 recompile the kernel to change these parameters.
322 - Reboot with the new kernel and enjoy.
324 IF SOMETHING GOES WRONG:
326 - If you have problems that seem to be due to kernel bugs, please check
327 the file MAINTAINERS to see if there is a particular person associated
328 with the part of the kernel that you are having trouble with. If there
329 isn't anyone listed there, then the second best thing is to mail
330 them to me (torvalds@linux-foundation.org), and possibly to any other
331 relevant mailing-list or to the newsgroup.
333 - In all bug-reports, *please* tell what kernel you are talking about,
334 how to duplicate the problem, and what your setup is (use your common
335 sense). If the problem is new, tell me so, and if the problem is
336 old, please try to tell me when you first noticed it.
338 - If the bug results in a message like
340 unable to handle kernel paging request at address C0000010
343 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
344 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
345 ds: xxxx es: xxxx fs: xxxx gs: xxxx
346 Pid: xx, process nr: xx
347 xx xx xx xx xx xx xx xx xx xx
349 or similar kernel debugging information on your screen or in your
350 system log, please duplicate it *exactly*. The dump may look
351 incomprehensible to you, but it does contain information that may
352 help debugging the problem. The text above the dump is also
353 important: it tells something about why the kernel dumped code (in
354 the above example it's due to a bad kernel pointer). More information
355 on making sense of the dump is in Documentation/oops-tracing.txt
357 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
358 as is, otherwise you will have to use the "ksymoops" program to make
359 sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
360 This utility can be downloaded from
361 ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
362 Alternately you can do the dump lookup by hand:
364 - In debugging dumps like the above, it helps enormously if you can
365 look up what the EIP value means. The hex value as such doesn't help
366 me or anybody else very much: it will depend on your particular
367 kernel setup. What you should do is take the hex value from the EIP
368 line (ignore the "0010:"), and look it up in the kernel namelist to
369 see which kernel function contains the offending address.
371 To find out the kernel function name, you'll need to find the system
372 binary associated with the kernel that exhibited the symptom. This is
373 the file 'linux/vmlinux'. To extract the namelist and match it against
374 the EIP from the kernel crash, do:
376 nm vmlinux | sort | less
378 This will give you a list of kernel addresses sorted in ascending
379 order, from which it is simple to find the function that contains the
380 offending address. Note that the address given by the kernel
381 debugging messages will not necessarily match exactly with the
382 function addresses (in fact, that is very unlikely), so you can't
383 just 'grep' the list: the list will, however, give you the starting
384 point of each kernel function, so by looking for the function that
385 has a starting address lower than the one you are searching for but
386 is followed by a function with a higher address you will find the one
387 you want. In fact, it may be a good idea to include a bit of
388 "context" in your problem report, giving a few lines around the
391 If you for some reason cannot do the above (you have a pre-compiled
392 kernel image or similar), telling me as much about your setup as
393 possible will help. Please read the REPORTING-BUGS document for details.
395 - Alternately, you can use gdb on a running kernel. (read-only; i.e. you
396 cannot change values or set break points.) To do this, first compile the
397 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
398 clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
400 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
401 You can now use all the usual gdb commands. The command to look up the
402 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
405 gdb'ing a non-running kernel currently fails because gdb (wrongly)
406 disregards the starting offset for which the kernel is compiled.