ia64/linux-2.6.18-xen.hg

view README @ 595:92247f7e5d8a

pvSCSI: add sanity checks

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Jul 08 09:29:42 2008 +0100 (2008-07-08)
parents 831230e53067
children
line source
1 Linux kernel release 2.6.xx <http://kernel.org>
3 These are the release notes for Linux version 2.6. 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 LINUX?
9 Linux is a clone of the operating system Unix, written from scratch by
10 Linus Torvalds with assistance from a loosely-knit team of hackers across
11 the Net. It aims towards POSIX and Single UNIX Specification compliance.
13 It has all the features you would expect in a modern fully-fledged Unix,
14 including true multitasking, virtual memory, shared libraries, demand
15 loading, shared copy-on-write executables, proper memory management,
16 and multistack networking including IPv4 and IPv6.
18 It is distributed under the GNU General Public License - see the
19 accompanying COPYING file for more details.
21 ON WHAT HARDWARE DOES IT RUN?
23 Although originally developed first for 32-bit x86-based PCs (386 or higher),
24 today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
25 UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH,
26 IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
27 and Renesas M32R architectures.
29 Linux is easily portable to most general-purpose 32- or 64-bit architectures
30 as long as they have a paged memory management unit (PMMU) and a port of the
31 GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
32 also been ported to a number of architectures without a PMMU, although
33 functionality is then obviously somewhat limited.
35 DOCUMENTATION:
37 - There is a lot of documentation available both in electronic form on
38 the Internet and in books, both Linux-specific and pertaining to
39 general UNIX questions. I'd recommend looking into the documentation
40 subdirectories on any Linux FTP site for the LDP (Linux Documentation
41 Project) books. This README is not meant to be documentation on the
42 system: there are much better sources available.
44 - There are various README files in the Documentation/ subdirectory:
45 these typically contain kernel-specific installation notes for some
46 drivers for example. See Documentation/00-INDEX for a list of what
47 is contained in each file. Please read the Changes file, as it
48 contains information about the problems, which may result by upgrading
49 your kernel.
51 - The Documentation/DocBook/ subdirectory contains several guides for
52 kernel developers and users. These guides can be rendered in a
53 number of formats: PostScript (.ps), PDF, and HTML, among others.
54 After installation, "make psdocs", "make pdfdocs", or "make htmldocs"
55 will render the documentation in the requested format.
57 INSTALLING the kernel:
59 - If you install the full sources, put the kernel tarball in a
60 directory where you have permissions (eg. your home directory) and
61 unpack it:
63 gzip -cd linux-2.6.XX.tar.gz | tar xvf -
65 or
66 bzip2 -dc linux-2.6.XX.tar.bz2 | tar xvf -
69 Replace "XX" with the version number of the latest kernel.
71 Do NOT use the /usr/src/linux area! This area has a (usually
72 incomplete) set of kernel headers that are used by the library header
73 files. They should match the library, and not get messed up by
74 whatever the kernel-du-jour happens to be.
76 - You can also upgrade between 2.6.xx releases by patching. Patches are
77 distributed in the traditional gzip and the newer bzip2 format. To
78 install by patching, get all the newer patch files, enter the
79 top level directory of the kernel source (linux-2.6.xx) and execute:
81 gzip -cd ../patch-2.6.xx.gz | patch -p1
83 or
84 bzip2 -dc ../patch-2.6.xx.bz2 | patch -p1
86 (repeat xx for all versions bigger than the version of your current
87 source tree, _in_order_) and you should be ok. You may want to remove
88 the backup files (xxx~ or xxx.orig), and make sure that there are no
89 failed patches (xxx# or xxx.rej). If there are, either you or me has
90 made a mistake.
92 Unlike patches for the 2.6.x kernels, patches for the 2.6.x.y kernels
93 (also known as the -stable kernels) are not incremental but instead apply
94 directly to the base 2.6.x kernel. Please read
95 Documentation/applying-patches.txt for more information.
97 Alternatively, the script patch-kernel can be used to automate this
98 process. It determines the current kernel version and applies any
99 patches found.
101 linux/scripts/patch-kernel linux
103 The first argument in the command above is the location of the
104 kernel source. Patches are applied from the current directory, but
105 an alternative directory can be specified as the second argument.
107 - If you are upgrading between releases using the stable series patches
108 (for example, patch-2.6.xx.y), note that these "dot-releases" are
109 not incremental and must be applied to the 2.6.xx base tree. For
110 example, if your base kernel is 2.6.12 and you want to apply the
111 2.6.12.3 patch, you do not and indeed must not first apply the
112 2.6.12.1 and 2.6.12.2 patches. Similarly, if you are running kernel
113 version 2.6.12.2 and want to jump to 2.6.12.3, you must first
114 reverse the 2.6.12.2 patch (that is, patch -R) _before_ applying
115 the 2.6.12.3 patch.
117 - Make sure you have no stale .o files and dependencies lying around:
119 cd linux
120 make mrproper
122 You should now have the sources correctly installed.
124 SOFTWARE REQUIREMENTS
126 Compiling and running the 2.6.xx kernels requires up-to-date
127 versions of various software packages. Consult
128 Documentation/Changes for the minimum version numbers required
129 and how to get updates for these packages. Beware that using
130 excessively old versions of these packages can cause indirect
131 errors that are very difficult to track down, so don't assume that
132 you can just update packages when obvious problems arise during
133 build or operation.
135 BUILD directory for the kernel:
137 When compiling the kernel all output files will per default be
138 stored together with the kernel source code.
139 Using the option "make O=output/dir" allow you to specify an alternate
140 place for the output files (including .config).
141 Example:
142 kernel source code: /usr/src/linux-2.6.N
143 build directory: /home/name/build/kernel
145 To configure and build the kernel use:
146 cd /usr/src/linux-2.6.N
147 make O=/home/name/build/kernel menuconfig
148 make O=/home/name/build/kernel
149 sudo make O=/home/name/build/kernel modules_install install
151 Please note: If the 'O=output/dir' option is used then it must be
152 used for all invocations of make.
154 CONFIGURING the kernel:
156 Do not skip this step even if you are only upgrading one minor
157 version. New configuration options are added in each release, and
158 odd problems will turn up if the configuration files are not set up
159 as expected. If you want to carry your existing configuration to a
160 new version with minimal work, use "make oldconfig", which will
161 only ask you for the answers to new questions.
163 - Alternate configuration commands are:
164 "make menuconfig" Text based color menus, radiolists & dialogs.
165 "make xconfig" X windows (Qt) based configuration tool.
166 "make gconfig" X windows (Gtk) based configuration tool.
167 "make oldconfig" Default all questions based on the contents of
168 your existing ./.config file and asking about
169 new config symbols.
170 "make silentoldconfig"
171 Like above, but avoids cluttering the screen
172 with questions already answered.
173 "make defconfig" Create a ./.config file by using the default
174 symbol values from arch/$ARCH/defconfig.
175 "make allyesconfig"
176 Create a ./.config file by setting symbol
177 values to 'y' as much as possible.
178 "make allmodconfig"
179 Create a ./.config file by setting symbol
180 values to 'm' as much as possible.
181 "make allnoconfig" Create a ./.config file by setting symbol
182 values to 'n' as much as possible.
183 "make randconfig" Create a ./.config file by setting symbol
184 values to random values.
186 The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
187 also use the environment variable KCONFIG_ALLCONFIG to specify a
188 filename that contains config options that the user requires to be
189 set to a specific value. If KCONFIG_ALLCONFIG=filename is not used,
190 "make *config" checks for a file named "all{yes/mod/no/random}.config"
191 for symbol values that are to be forced. If this file is not found,
192 it checks for a file named "all.config" to contain forced values.
194 NOTES on "make config":
195 - having unnecessary drivers will make the kernel bigger, and can
196 under some circumstances lead to problems: probing for a
197 nonexistent controller card may confuse your other controllers
198 - compiling the kernel with "Processor type" set higher than 386
199 will result in a kernel that does NOT work on a 386. The
200 kernel will detect this on bootup, and give up.
201 - A kernel with math-emulation compiled in will still use the
202 coprocessor if one is present: the math emulation will just
203 never get used in that case. The kernel will be slightly larger,
204 but will work on different machines regardless of whether they
205 have a math coprocessor or not.
206 - the "kernel hacking" configuration details usually result in a
207 bigger or slower kernel (or both), and can even make the kernel
208 less stable by configuring some routines to actively try to
209 break bad code to find kernel problems (kmalloc()). Thus you
210 should probably answer 'n' to the questions for
211 "development", "experimental", or "debugging" features.
213 COMPILING the kernel:
215 - Make sure you have at least gcc 3.2 available.
216 For more information, refer to Documentation/Changes.
218 Please note that you can still run a.out user programs with this kernel.
220 - Do a "make" to create a compressed kernel image. It is also
221 possible to do "make install" if you have lilo installed to suit the
222 kernel makefiles, but you may want to check your particular lilo setup first.
224 To do the actual install you have to be root, but none of the normal
225 build should require that. Don't take the name of root in vain.
227 - If you configured any of the parts of the kernel as `modules', you
228 will also have to do "make modules_install".
230 - Keep a backup kernel handy in case something goes wrong. This is
231 especially true for the development releases, since each new release
232 contains new code which has not been debugged. Make sure you keep a
233 backup of the modules corresponding to that kernel, as well. If you
234 are installing a new kernel with the same version number as your
235 working kernel, make a backup of your modules directory before you
236 do a "make modules_install".
237 Alternatively, before compiling, use the kernel config option
238 "LOCALVERSION" to append a unique suffix to the regular kernel version.
239 LOCALVERSION can be set in the "General Setup" menu.
241 - In order to boot your new kernel, you'll need to copy the kernel
242 image (e.g. .../linux/arch/i386/boot/bzImage after compilation)
243 to the place where your regular bootable kernel is found.
245 - Booting a kernel directly from a floppy without the assistance of a
246 bootloader such as LILO, is no longer supported.
248 If you boot Linux from the hard drive, chances are you use LILO which
249 uses the kernel image as specified in the file /etc/lilo.conf. The
250 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
251 /boot/bzImage. To use the new kernel, save a copy of the old image
252 and copy the new image over the old one. Then, you MUST RERUN LILO
253 to update the loading map!! If you don't, you won't be able to boot
254 the new kernel image.
256 Reinstalling LILO is usually a matter of running /sbin/lilo.
257 You may wish to edit /etc/lilo.conf to specify an entry for your
258 old kernel image (say, /vmlinux.old) in case the new one does not
259 work. See the LILO docs for more information.
261 After reinstalling LILO, you should be all set. Shutdown the system,
262 reboot, and enjoy!
264 If you ever need to change the default root device, video mode,
265 ramdisk size, etc. in the kernel image, use the 'rdev' program (or
266 alternatively the LILO boot options when appropriate). No need to
267 recompile the kernel to change these parameters.
269 - Reboot with the new kernel and enjoy.
271 IF SOMETHING GOES WRONG:
273 - If you have problems that seem to be due to kernel bugs, please check
274 the file MAINTAINERS to see if there is a particular person associated
275 with the part of the kernel that you are having trouble with. If there
276 isn't anyone listed there, then the second best thing is to mail
277 them to me (torvalds@osdl.org), and possibly to any other relevant
278 mailing-list or to the newsgroup.
280 - In all bug-reports, *please* tell what kernel you are talking about,
281 how to duplicate the problem, and what your setup is (use your common
282 sense). If the problem is new, tell me so, and if the problem is
283 old, please try to tell me when you first noticed it.
285 - If the bug results in a message like
287 unable to handle kernel paging request at address C0000010
288 Oops: 0002
289 EIP: 0010:XXXXXXXX
290 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
291 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
292 ds: xxxx es: xxxx fs: xxxx gs: xxxx
293 Pid: xx, process nr: xx
294 xx xx xx xx xx xx xx xx xx xx
296 or similar kernel debugging information on your screen or in your
297 system log, please duplicate it *exactly*. The dump may look
298 incomprehensible to you, but it does contain information that may
299 help debugging the problem. The text above the dump is also
300 important: it tells something about why the kernel dumped code (in
301 the above example it's due to a bad kernel pointer). More information
302 on making sense of the dump is in Documentation/oops-tracing.txt
304 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
305 as is, otherwise you will have to use the "ksymoops" program to make
306 sense of the dump. This utility can be downloaded from
307 ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops.
308 Alternately you can do the dump lookup by hand:
310 - In debugging dumps like the above, it helps enormously if you can
311 look up what the EIP value means. The hex value as such doesn't help
312 me or anybody else very much: it will depend on your particular
313 kernel setup. What you should do is take the hex value from the EIP
314 line (ignore the "0010:"), and look it up in the kernel namelist to
315 see which kernel function contains the offending address.
317 To find out the kernel function name, you'll need to find the system
318 binary associated with the kernel that exhibited the symptom. This is
319 the file 'linux/vmlinux'. To extract the namelist and match it against
320 the EIP from the kernel crash, do:
322 nm vmlinux | sort | less
324 This will give you a list of kernel addresses sorted in ascending
325 order, from which it is simple to find the function that contains the
326 offending address. Note that the address given by the kernel
327 debugging messages will not necessarily match exactly with the
328 function addresses (in fact, that is very unlikely), so you can't
329 just 'grep' the list: the list will, however, give you the starting
330 point of each kernel function, so by looking for the function that
331 has a starting address lower than the one you are searching for but
332 is followed by a function with a higher address you will find the one
333 you want. In fact, it may be a good idea to include a bit of
334 "context" in your problem report, giving a few lines around the
335 interesting one.
337 If you for some reason cannot do the above (you have a pre-compiled
338 kernel image or similar), telling me as much about your setup as
339 possible will help.
341 - Alternately, you can use gdb on a running kernel. (read-only; i.e. you
342 cannot change values or set break points.) To do this, first compile the
343 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
344 clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
346 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
347 You can now use all the usual gdb commands. The command to look up the
348 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
349 with the EIP value.)
351 gdb'ing a non-running kernel currently fails because gdb (wrongly)
352 disregards the starting offset for which the kernel is compiled.