2 Linux kernel release 2.0.xx
4 These are the release notes for linux version 2.0. Read them carefully,
5 as they tell you what this is all about, explain how to install the
6 kernel, and what to do if something goes wrong.
8 WHAT IS LINUX?
10 Linux is a Unix clone written from scratch by Linus Torvalds with
11 assistance from a loosely-knit team of hackers across the Net.
12 It aims towards POSIX compliance.
14 It has all the features you would expect in a modern fully-fledged
15 Unix, including true multitasking, virtual memory, shared libraries,
16 demand loading, shared copy-on-write executables, proper memory
17 management and TCP/IP networking.
19 It is distributed under the GNU General Public License - see the
20 accompanying COPYING file for more details.
22 ON WHAT HARDWARE DOES IT RUN?
24 Linux was first developed for 386/486-based PCs. These days it also
25 runs on DEC Alphas, SUN Sparcs, M68000 machines (like Atari and Amiga),
26 MIPS and PowerPC.
30 - there is a lot of documentation available both in electronic form on
31 the internet and in books, both Linux-specific and pertaining to
32 general UNIX questions. I'd recommend looking into the documentation
33 subdirectories on any Linux ftp site for the LDP (Linux Documentation
34 Project) books. This README is not meant to be documentation on the
35 system: there are much better sources available.
37 - There are various readme's in the kernel Documentation/ subdirectory:
38 these typically contain kernel-specific installation notes for some
39 drivers for example. See ./Documentation/00-INDEX for a list of what
40 is contained in each file.
42 INSTALLING the kernel:
44 - If you install the full sources, do a
46 cd /usr/src
47 gzip -cd linux-2.0.XX.tar.gz | tar xfv -
49 to get it all put in place. Replace "XX" with the version number of the
50 latest kernel. If you use GNU tar,
52 cd /usr/src
53 tar -xzvf linux-2.0.XX.tar.gz
55 is equivalent.
57 - You can also upgrade between 2.0.xx releases by patching. Each
58 patch that is released for 2.0.xx contains only bugfixes. No
59 new features will be added to the Linux kernel 2.0 any more. If
60 you are interested in new kernel features, you may want to
61 help developing a more recent kernel.
63 To patch to a newer 2.0 kernel version, get all the newer files
64 (you will find these patches at the kernel FTP servers:
65 <URL:ftp://ftp.xx.kernel.org/pub/linux/kernel/v2.0/>, replace
66 xx with your two letter country code here, e.g. se for Sweden),
67 then do:
69 cd /usr/src/linux
70 gzip -cd patchXX.gz | patch -p0
72 (repeat xx for all versions bigger than the version of your current
73 source tree, _in_order_) and you should be ok. You may want to remove
74 the backup files (xxx~ or xxx.orig), and make sure that there are no
75 failed patches (xxx# or xxx.rej). If there are, either you or me has
76 made a mistake.
78 Alternatively, the script patch-kernel can be used to automate this
79 process. It determines the current kernel version and applies any
80 patches found.
82 cd /usr/src
85 The default directory for the kernel source is /usr/src/linux, but
86 can be specified as the first argument. Patches are applied from
87 the current directory, but an alternative directory can be specified
88 as the second argument.
90 - make sure you have no stale .o files and dependencies lying around:
92 cd /usr/src/linux
93 make mrproper
95 You should now have the sources correctly installed.
97 CONFIGURING the kernel:
99 - do a "make config" to configure the basic kernel. "make config"
100 needs bash to work: it will search for bash in $BASH, /bin/bash and
101 /bin/sh (in that order), so hopefully one of those is correct.
103 - Alternate configuration commands are:
104 "make menuconfig" Text based color menus, radiolists & dialogs.
105 "make xconfig" X window system based configuration tool.
107 NOTES on "make config":
108 - having unnecessary drivers will make the kernel bigger, and can
109 under some circumstances lead to problems: probing for a
110 nonexistent controller card may confuse your other controllers
111 - compiling the kernel with "Processor type" set higher than 386
112 will result in a kernel that does NOT work on a 386. The
113 kernel will detect this on bootup, and give up.
114 - A kernel with math-emulation compiled in will still use the
115 coprocessor if one is present: the math emulation will just
116 never get used in that case. The kernel will be slightly larger,
117 but will work on different machines regardless of whether they
118 have a math coprocessor or not.
119 - the "kernel hacking" configuration details usually result in a
120 bigger or slower kernel (or both), and can even make the kernel
121 less stable by configuring some routines to actively try to
122 break bad code to find kernel problems (kmalloc()). Thus you
123 should probably answer 'n' to the questions for a "production"
126 - Check the top Makefile for further site-dependent configuration
127 (default SVGA mode etc).
129 - Finally, do a "make dep" to set up all the dependencies correctly.
131 COMPILING the kernel:
133 - make sure you have gcc-2.6.3 or newer available. It seems older gcc
134 versions can have problems compiling newer versions of linux. If you
135 upgrade your compiler, remember to get the new binutils package too
136 (for as/ld/nm and company).
138 - do a "make zImage" to create a compressed kernel image. If you want
139 to make a bootdisk (without root filesystem or lilo), insert a floppy
140 in your A: drive, and do a "make zdisk". It is also possible to do
141 "make zlilo" if you have lilo installed to suit the kernel makefiles,
142 but you may want to check your particular lilo setup first.
144 - if your kernel is too large for "make zImage", use "make bzImage"
147 - if you configured any of the parts of the kernel as `modules', you
148 will have to do "make modules" followed by "make modules_install".
149 Read Documentation/modules.txt for more information. For example,
150 an explanation of how to use the modules is included there.
152 - keep a backup kernel handy in case something goes wrong. This is
153 especially true for the development releases, since each new release
154 contains new code which has not been debugged.
156 - In order to boot your new kernel, you'll need to copy the kernel
157 image (found in /usr/src/linux/arch/i386/boot/zImage after compilation)
158 to the place where your regular bootable kernel is found.
160 For some, this is on a floppy disk, in which case you can "cp
161 /usr/src/linux/arch/i386/boot/zImage /dev/fd0" to make a bootable
162 floppy. Note that as of Linux 2.0.0, a kernel copied to a 720k
163 double-density 3.5" floppy disk no longer boots. In this case,
164 it is highly recommended that you install LILO on your
165 double-density bootfloppy or switch to high-density floppies.
167 If you boot Linux from the hard drive, chances are you use LILO which
168 uses the kernel image as specified in the file /etc/lilo.conf. The
169 kernel image file is usually /vmlinuz, /zImage, or /boot/vmlinuz.
170 To use the new kernel, copy the new image over the old one (save a
171 backup of the original!). Then, you MUST RERUN LILO to update the
172 loading map!! If you don't, you won't be able to boot the new kernel
175 Reinstalling LILO is usually a matter of running /sbin/lilo.
176 You may wish to edit /etc/lilo.conf to specify an entry for your
177 old kernel image (say, /vmlinux.old) in case the new one does not
178 work. See the LILO docs for more information.
180 After reinstalling LILO, you should be all set. Shutdown the system,
181 reboot, and enjoy!
183 If you ever need to change the default root device, video mode,
184 ramdisk size, etc. in the kernel image, use the 'rdev' program (or
185 alternatively the LILO boot options when appropriate). No need to
186 recompile the kernel to change these parameters.
188 - reboot with the new kernel and enjoy.
190 IF SOMETHING GOES WRONG:
192 - if you have problems that seem to be due to kernel bugs, please check
193 the file MAINTAINERS to see if there is a particular person associated
194 with the part of the kernel that you are having trouble with. If there
195 isn't anyone listed there, then the second best thing is to mail
196 them to me (David Weinehall, firstname.lastname@example.org), and possibly to any other
197 relevant mailing-list or to the newsgroup.
199 - In all bug-reports, *please* tell what kernel you are talking about,
200 how to duplicate the problem, and what your setup is (use your common
201 sense). If the problem is new, tell me so, and if the problem is
202 old, please try to tell me when you first noticed it.
204 - if the bug results in a message like
206 unable to handle kernel paging request at address C0000010
207 Oops: 0002
208 EIP: 0010:XXXXXXXX
209 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
210 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
211 ds: xxxx es: xxxx fs: xxxx gs: xxxx
212 Pid: xx, process nr: xx
213 xx xx xx xx xx xx xx xx xx xx
215 or similar kernel debugging information on your screen or in your
216 system log, please duplicate it *exactly*. The dump may look
217 incomprehensible to you, but it does contain information that may
218 help debugging the problem. The text above the dump is also
219 important: it tells something about why the kernel dumped code (in
220 the above example it's due to a bad kernel pointer). More information
221 on making sense of the dump is in Documentation/oops-tracing.txt
223 - You can use the "ksymoops" program to make sense of the dump. Find
224 the C++ sources under the scripts/ directory to avoid having to do
225 the dump lookup by hand:
227 - in debugging dumps like the above, it helps enormously if you can
228 look up what the EIP value means. The hex value as such doesn't help
229 me or anybody else very much: it will depend on your particular
230 kernel setup. What you should do is take the hex value from the EIP
231 line (ignore the "0010:"), and look it up in the kernel namelist to
232 see which kernel function contains the offending address.
234 To find out the kernel function name, you'll need to find the system
235 binary associated with the kernel that exhibited the symptom. This is
236 the file 'linux/vmlinux'. To extract the namelist and match it against
237 the EIP from the kernel crash, do:
239 nm vmlinux | sort | less
241 This will give you a list of kernel addresses sorted in ascending
242 order, from which it is simple to find the function that contains the
243 offending address. Note that the address given by the kernel
244 debugging messages will not necessarily match exactly with the
245 function addresses (in fact, that is very unlikely), so you can't
246 just 'grep' the list: the list will, however, give you the starting
247 point of each kernel function, so by looking for the function that
248 has a starting address lower than the one you are searching for but
249 is followed by a function with a higher address you will find the one
250 you want. In fact, it may be a good idea to include a bit of
251 "context" in your problem report, giving a few lines around the
252 interesting one.
254 If you for some reason cannot do the above (you have a pre-compiled
255 kernel image or similar), telling me as much about your setup as
256 possible will help.
258 - alternately, you can use gdb on a running kernel. (read-only; i.e. you
259 cannot change values or set break points.) To do this, first compile the
260 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
261 clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
263 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
264 You can now use all the usual gdb commands. The command to look up the
265 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
266 with the EIP value.)
268 gdb'ing a non-running kernel currently fails because gdb (wrongly)
269 disregards the starting offset for which the kernel is compiled.