Eric Lee / smarc-ti-linux-kernel

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Commit 80b810b276cf89587cdaa103e39027813b1be46c

Authored by Steven Rostedt
Committed by Linus Torvalds
1 parent d8dc91b753
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

localmodconfig: Document localmodconfig in README 

Someone (over a year ago :-p) asked me to document localmodconfig in the
README file in the source code.  I thought it was a good idea but other
things were more important and I simply forgot about it.  Well, I
stumbled on the email asking me about this and I'm sending it out now.

Signed-off-by: Steven "Mr. Procrastinator" Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 18 additions and 0 deletions Inline Diff

1 Linux kernel release 3.x <http://kernel.org/> 1 Linux kernel release 3.x <http://kernel.org/>
2 2
3 These are the release notes for Linux version 3. Read them carefully, 3 These are the release notes for Linux version 3. Read them carefully,
4 as they tell you what this is all about, explain how to install the 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. 5 kernel, and what to do if something goes wrong.
6 6
7 WHAT IS LINUX? 7 WHAT IS LINUX?
8 8
9 Linux is a clone of the operating system Unix, written from scratch by 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 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. 11 the Net. It aims towards POSIX and Single UNIX Specification compliance.
12 12
13 It has all the features you would expect in a modern fully-fledged Unix, 13 It has all the features you would expect in a modern fully-fledged Unix,
14 including true multitasking, virtual memory, shared libraries, demand 14 including true multitasking, virtual memory, shared libraries, demand
15 loading, shared copy-on-write executables, proper memory management, 15 loading, shared copy-on-write executables, proper memory management,
16 and multistack networking including IPv4 and IPv6. 16 and multistack networking including IPv4 and IPv6.
17 17
18 It is distributed under the GNU General Public License - see the 18 It is distributed under the GNU General Public License - see the
19 accompanying COPYING file for more details. 19 accompanying COPYING file for more details.
20 20
21 ON WHAT HARDWARE DOES IT RUN? 21 ON WHAT HARDWARE DOES IT RUN?
22 22
23 Although originally developed first for 32-bit x86-based PCs (386 or higher), 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 24 today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
25 UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell, 25 UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
26 IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS, 26 IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
27 Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures. 27 Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures.
28 28
29 Linux is easily portable to most general-purpose 32- or 64-bit 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 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 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 32 also been ported to a number of architectures without a PMMU, although
33 functionality is then obviously somewhat limited. 33 functionality is then obviously somewhat limited.
34 Linux has also been ported to itself. You can now run the kernel as a 34 Linux has also been ported to itself. You can now run the kernel as a
35 userspace application - this is called UserMode Linux (UML). 35 userspace application - this is called UserMode Linux (UML).
36 36
37 DOCUMENTATION: 37 DOCUMENTATION:
38 38
39 - There is a lot of documentation available both in electronic form on 39 - There is a lot of documentation available both in electronic form on
40 the Internet and in books, both Linux-specific and pertaining to 40 the Internet and in books, both Linux-specific and pertaining to
41 general UNIX questions. I'd recommend looking into the documentation 41 general UNIX questions. I'd recommend looking into the documentation
42 subdirectories on any Linux FTP site for the LDP (Linux Documentation 42 subdirectories on any Linux FTP site for the LDP (Linux Documentation
43 Project) books. This README is not meant to be documentation on the 43 Project) books. This README is not meant to be documentation on the
44 system: there are much better sources available. 44 system: there are much better sources available.
45 45
46 - There are various README files in the Documentation/ subdirectory: 46 - There are various README files in the Documentation/ subdirectory:
47 these typically contain kernel-specific installation notes for some 47 these typically contain kernel-specific installation notes for some
48 drivers for example. See Documentation/00-INDEX for a list of what 48 drivers for example. See Documentation/00-INDEX for a list of what
49 is contained in each file. Please read the Changes file, as it 49 is contained in each file. Please read the Changes file, as it
50 contains information about the problems, which may result by upgrading 50 contains information about the problems, which may result by upgrading
51 your kernel. 51 your kernel.
52 52
53 - The Documentation/DocBook/ subdirectory contains several guides for 53 - The Documentation/DocBook/ subdirectory contains several guides for
54 kernel developers and users. These guides can be rendered in a 54 kernel developers and users. These guides can be rendered in a
55 number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others. 55 number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others.
56 After installation, "make psdocs", "make pdfdocs", "make htmldocs", 56 After installation, "make psdocs", "make pdfdocs", "make htmldocs",
57 or "make mandocs" will render the documentation in the requested format. 57 or "make mandocs" will render the documentation in the requested format.
58 58
59 INSTALLING the kernel source: 59 INSTALLING the kernel source:
60 60
61 - If you install the full sources, put the kernel tarball in a 61 - If you install the full sources, put the kernel tarball in a
62 directory where you have permissions (eg. your home directory) and 62 directory where you have permissions (eg. your home directory) and
63 unpack it: 63 unpack it:
64 64
65 gzip -cd linux-3.X.tar.gz | tar xvf - 65 gzip -cd linux-3.X.tar.gz | tar xvf -
66 66
67 or 67 or
68 68
69 bzip2 -dc linux-3.X.tar.bz2 | tar xvf - 69 bzip2 -dc linux-3.X.tar.bz2 | tar xvf -
70 70
71 Replace "X" with the version number of the latest kernel. 71 Replace "X" with the version number of the latest kernel.
72 72
73 Do NOT use the /usr/src/linux area! This area has a (usually 73 Do NOT use the /usr/src/linux area! This area has a (usually
74 incomplete) set of kernel headers that are used by the library header 74 incomplete) set of kernel headers that are used by the library header
75 files. They should match the library, and not get messed up by 75 files. They should match the library, and not get messed up by
76 whatever the kernel-du-jour happens to be. 76 whatever the kernel-du-jour happens to be.
77 77
78 - You can also upgrade between 3.x releases by patching. Patches are 78 - You can also upgrade between 3.x releases by patching. Patches are
79 distributed in the traditional gzip and the newer bzip2 format. To 79 distributed in the traditional gzip and the newer bzip2 format. To
80 install by patching, get all the newer patch files, enter the 80 install by patching, get all the newer patch files, enter the
81 top level directory of the kernel source (linux-3.X) and execute: 81 top level directory of the kernel source (linux-3.X) and execute:
82 82
83 gzip -cd ../patch-3.x.gz | patch -p1 83 gzip -cd ../patch-3.x.gz | patch -p1
84 84
85 or 85 or
86 86
87 bzip2 -dc ../patch-3.x.bz2 | patch -p1 87 bzip2 -dc ../patch-3.x.bz2 | patch -p1
88 88
89 Replace "x" for all versions bigger than the version "X" of your current 89 Replace "x" for all versions bigger than the version "X" of your current
90 source tree, _in_order_, and you should be ok. You may want to remove 90 source tree, _in_order_, and you should be ok. You may want to remove
91 the backup files (some-file-name~ or some-file-name.orig), and make sure 91 the backup files (some-file-name~ or some-file-name.orig), and make sure
92 that there are no failed patches (some-file-name# or some-file-name.rej). 92 that there are no failed patches (some-file-name# or some-file-name.rej).
93 If there are, either you or I have made a mistake. 93 If there are, either you or I have made a mistake.
94 94
95 Unlike patches for the 3.x kernels, patches for the 3.x.y kernels 95 Unlike patches for the 3.x kernels, patches for the 3.x.y kernels
96 (also known as the -stable kernels) are not incremental but instead apply 96 (also known as the -stable kernels) are not incremental but instead apply
97 directly to the base 3.x kernel. For example, if your base kernel is 3.0 97 directly to the base 3.x kernel. For example, if your base kernel is 3.0
98 and you want to apply the 3.0.3 patch, you must not first apply the 3.0.1 98 and you want to apply the 3.0.3 patch, you must not first apply the 3.0.1
99 and 3.0.2 patches. Similarly, if you are running kernel version 3.0.2 and 99 and 3.0.2 patches. Similarly, if you are running kernel version 3.0.2 and
100 want to jump to 3.0.3, you must first reverse the 3.0.2 patch (that is, 100 want to jump to 3.0.3, you must first reverse the 3.0.2 patch (that is,
101 patch -R) _before_ applying the 3.0.3 patch. You can read more on this in 101 patch -R) _before_ applying the 3.0.3 patch. You can read more on this in
102 Documentation/applying-patches.txt 102 Documentation/applying-patches.txt
103 103
104 Alternatively, the script patch-kernel can be used to automate this 104 Alternatively, the script patch-kernel can be used to automate this
105 process. It determines the current kernel version and applies any 105 process. It determines the current kernel version and applies any
106 patches found. 106 patches found.
107 107
108 linux/scripts/patch-kernel linux 108 linux/scripts/patch-kernel linux
109 109
110 The first argument in the command above is the location of the 110 The first argument in the command above is the location of the
111 kernel source. Patches are applied from the current directory, but 111 kernel source. Patches are applied from the current directory, but
112 an alternative directory can be specified as the second argument. 112 an alternative directory can be specified as the second argument.
113 113
114 - Make sure you have no stale .o files and dependencies lying around: 114 - Make sure you have no stale .o files and dependencies lying around:
115 115
116 cd linux 116 cd linux
117 make mrproper 117 make mrproper
118 118
119 You should now have the sources correctly installed. 119 You should now have the sources correctly installed.
120 120
121 SOFTWARE REQUIREMENTS 121 SOFTWARE REQUIREMENTS
122 122
123 Compiling and running the 3.x kernels requires up-to-date 123 Compiling and running the 3.x kernels requires up-to-date
124 versions of various software packages. Consult 124 versions of various software packages. Consult
125 Documentation/Changes for the minimum version numbers required 125 Documentation/Changes for the minimum version numbers required
126 and how to get updates for these packages. Beware that using 126 and how to get updates for these packages. Beware that using
127 excessively old versions of these packages can cause indirect 127 excessively old versions of these packages can cause indirect
128 errors that are very difficult to track down, so don't assume that 128 errors that are very difficult to track down, so don't assume that
129 you can just update packages when obvious problems arise during 129 you can just update packages when obvious problems arise during
130 build or operation. 130 build or operation.
131 131
132 BUILD directory for the kernel: 132 BUILD directory for the kernel:
133 133
134 When compiling the kernel, all output files will per default be 134 When compiling the kernel, all output files will per default be
135 stored together with the kernel source code. 135 stored together with the kernel source code.
136 Using the option "make O=output/dir" allow you to specify an alternate 136 Using the option "make O=output/dir" allow you to specify an alternate
137 place for the output files (including .config). 137 place for the output files (including .config).
138 Example: 138 Example:
139 139
140 kernel source code: /usr/src/linux-3.X 140 kernel source code: /usr/src/linux-3.X
141 build directory: /home/name/build/kernel 141 build directory: /home/name/build/kernel
142 142
143 To configure and build the kernel, use: 143 To configure and build the kernel, use:
144 144
145 cd /usr/src/linux-3.X 145 cd /usr/src/linux-3.X
146 make O=/home/name/build/kernel menuconfig 146 make O=/home/name/build/kernel menuconfig
147 make O=/home/name/build/kernel 147 make O=/home/name/build/kernel
148 sudo make O=/home/name/build/kernel modules_install install 148 sudo make O=/home/name/build/kernel modules_install install
149 149
150 Please note: If the 'O=output/dir' option is used, then it must be 150 Please note: If the 'O=output/dir' option is used, then it must be
151 used for all invocations of make. 151 used for all invocations of make.
152 152
153 CONFIGURING the kernel: 153 CONFIGURING the kernel:
154 154
155 Do not skip this step even if you are only upgrading one minor 155 Do not skip this step even if you are only upgrading one minor
156 version. New configuration options are added in each release, and 156 version. New configuration options are added in each release, and
157 odd problems will turn up if the configuration files are not set up 157 odd problems will turn up if the configuration files are not set up
158 as expected. If you want to carry your existing configuration to a 158 as expected. If you want to carry your existing configuration to a
159 new version with minimal work, use "make oldconfig", which will 159 new version with minimal work, use "make oldconfig", which will
160 only ask you for the answers to new questions. 160 only ask you for the answers to new questions.
161 161
162 - Alternative configuration commands are: 162 - Alternative configuration commands are:
163 163
164 "make config" Plain text interface. 164 "make config" Plain text interface.
165 165
166 "make menuconfig" Text based color menus, radiolists & dialogs. 166 "make menuconfig" Text based color menus, radiolists & dialogs.
167 167
168 "make nconfig" Enhanced text based color menus. 168 "make nconfig" Enhanced text based color menus.
169 169
170 "make xconfig" X windows (Qt) based configuration tool. 170 "make xconfig" X windows (Qt) based configuration tool.
171 171
172 "make gconfig" X windows (Gtk) based configuration tool. 172 "make gconfig" X windows (Gtk) based configuration tool.
173 173
174 "make oldconfig" Default all questions based on the contents of 174 "make oldconfig" Default all questions based on the contents of
175 your existing ./.config file and asking about 175 your existing ./.config file and asking about
176 new config symbols. 176 new config symbols.
177 177
178 "make silentoldconfig" 178 "make silentoldconfig"
179 Like above, but avoids cluttering the screen 179 Like above, but avoids cluttering the screen
180 with questions already answered. 180 with questions already answered.
181 Additionally updates the dependencies. 181 Additionally updates the dependencies.
182 182
183 "make defconfig" Create a ./.config file by using the default 183 "make defconfig" Create a ./.config file by using the default
184 symbol values from either arch/$ARCH/defconfig 184 symbol values from either arch/$ARCH/defconfig
185 or arch/$ARCH/configs/${PLATFORM}_defconfig, 185 or arch/$ARCH/configs/${PLATFORM}_defconfig,
186 depending on the architecture. 186 depending on the architecture.
187 187
188 "make ${PLATFORM}_defconfig" 188 "make ${PLATFORM}_defconfig"
189 Create a ./.config file by using the default 189 Create a ./.config file by using the default
190 symbol values from 190 symbol values from
191 arch/$ARCH/configs/${PLATFORM}_defconfig. 191 arch/$ARCH/configs/${PLATFORM}_defconfig.
192 Use "make help" to get a list of all available 192 Use "make help" to get a list of all available
193 platforms of your architecture. 193 platforms of your architecture.
194 194
195 "make allyesconfig" 195 "make allyesconfig"
196 Create a ./.config file by setting symbol 196 Create a ./.config file by setting symbol
197 values to 'y' as much as possible. 197 values to 'y' as much as possible.
198 198
199 "make allmodconfig" 199 "make allmodconfig"
200 Create a ./.config file by setting symbol 200 Create a ./.config file by setting symbol
201 values to 'm' as much as possible. 201 values to 'm' as much as possible.
202 202
203 "make allnoconfig" Create a ./.config file by setting symbol 203 "make allnoconfig" Create a ./.config file by setting symbol
204 values to 'n' as much as possible. 204 values to 'n' as much as possible.
205 205
206 "make randconfig" Create a ./.config file by setting symbol 206 "make randconfig" Create a ./.config file by setting symbol
207 values to random values. 207 values to random values.
208 208
209 "make localmodconfig" Create a config based on current config and
210 loaded modules (lsmod). Disables any module
211 option that is not needed for the loaded modules.
212
213 To create a localmodconfig for another machine,
214 store the lsmod of that machine into a file
215 and pass it in as a LSMOD parameter.
216
217 target$ lsmod > /tmp/mylsmod
218 target$ scp /tmp/mylsmod host:/tmp
219
220 host$ make LSMOD=/tmp/mylsmod localmodconfig
221
222 The above also works when cross compiling.
223
224 "make localyesconfig" Similar to localmodconfig, except it will convert
225 all module options to built in (=y) options.
226
209 You can find more information on using the Linux kernel config tools 227 You can find more information on using the Linux kernel config tools
210 in Documentation/kbuild/kconfig.txt. 228 in Documentation/kbuild/kconfig.txt.
211 229
212 - NOTES on "make config": 230 - NOTES on "make config":
213 231
214 - Having unnecessary drivers will make the kernel bigger, and can 232 - Having unnecessary drivers will make the kernel bigger, and can
215 under some circumstances lead to problems: probing for a 233 under some circumstances lead to problems: probing for a
216 nonexistent controller card may confuse your other controllers 234 nonexistent controller card may confuse your other controllers
217 235
218 - Compiling the kernel with "Processor type" set higher than 386 236 - Compiling the kernel with "Processor type" set higher than 386
219 will result in a kernel that does NOT work on a 386. The 237 will result in a kernel that does NOT work on a 386. The
220 kernel will detect this on bootup, and give up. 238 kernel will detect this on bootup, and give up.
221 239
222 - A kernel with math-emulation compiled in will still use the 240 - A kernel with math-emulation compiled in will still use the
223 coprocessor if one is present: the math emulation will just 241 coprocessor if one is present: the math emulation will just
224 never get used in that case. The kernel will be slightly larger, 242 never get used in that case. The kernel will be slightly larger,
225 but will work on different machines regardless of whether they 243 but will work on different machines regardless of whether they
226 have a math coprocessor or not. 244 have a math coprocessor or not.
227 245
228 - The "kernel hacking" configuration details usually result in a 246 - The "kernel hacking" configuration details usually result in a
229 bigger or slower kernel (or both), and can even make the kernel 247 bigger or slower kernel (or both), and can even make the kernel
230 less stable by configuring some routines to actively try to 248 less stable by configuring some routines to actively try to
231 break bad code to find kernel problems (kmalloc()). Thus you 249 break bad code to find kernel problems (kmalloc()). Thus you
232 should probably answer 'n' to the questions for "development", 250 should probably answer 'n' to the questions for "development",
233 "experimental", or "debugging" features. 251 "experimental", or "debugging" features.
234 252
235 COMPILING the kernel: 253 COMPILING the kernel:
236 254
237 - Make sure you have at least gcc 3.2 available. 255 - Make sure you have at least gcc 3.2 available.
238 For more information, refer to Documentation/Changes. 256 For more information, refer to Documentation/Changes.
239 257
240 Please note that you can still run a.out user programs with this kernel. 258 Please note that you can still run a.out user programs with this kernel.
241 259
242 - Do a "make" to create a compressed kernel image. It is also 260 - Do a "make" to create a compressed kernel image. It is also
243 possible to do "make install" if you have lilo installed to suit the 261 possible to do "make install" if you have lilo installed to suit the
244 kernel makefiles, but you may want to check your particular lilo setup first. 262 kernel makefiles, but you may want to check your particular lilo setup first.
245 263
246 To do the actual install, you have to be root, but none of the normal 264 To do the actual install, you have to be root, but none of the normal
247 build should require that. Don't take the name of root in vain. 265 build should require that. Don't take the name of root in vain.
248 266
249 - If you configured any of the parts of the kernel as `modules', you 267 - If you configured any of the parts of the kernel as `modules', you
250 will also have to do "make modules_install". 268 will also have to do "make modules_install".
251 269
252 - Verbose kernel compile/build output: 270 - Verbose kernel compile/build output:
253 271
254 Normally, the kernel build system runs in a fairly quiet mode (but not 272 Normally, the kernel build system runs in a fairly quiet mode (but not
255 totally silent). However, sometimes you or other kernel developers need 273 totally silent). However, sometimes you or other kernel developers need
256 to see compile, link, or other commands exactly as they are executed. 274 to see compile, link, or other commands exactly as they are executed.
257 For this, use "verbose" build mode. This is done by inserting 275 For this, use "verbose" build mode. This is done by inserting
258 "V=1" in the "make" command. E.g.: 276 "V=1" in the "make" command. E.g.:
259 277
260 make V=1 all 278 make V=1 all
261 279
262 To have the build system also tell the reason for the rebuild of each 280 To have the build system also tell the reason for the rebuild of each
263 target, use "V=2". The default is "V=0". 281 target, use "V=2". The default is "V=0".
264 282
265 - Keep a backup kernel handy in case something goes wrong. This is 283 - Keep a backup kernel handy in case something goes wrong. This is
266 especially true for the development releases, since each new release 284 especially true for the development releases, since each new release
267 contains new code which has not been debugged. Make sure you keep a 285 contains new code which has not been debugged. Make sure you keep a
268 backup of the modules corresponding to that kernel, as well. If you 286 backup of the modules corresponding to that kernel, as well. If you
269 are installing a new kernel with the same version number as your 287 are installing a new kernel with the same version number as your
270 working kernel, make a backup of your modules directory before you 288 working kernel, make a backup of your modules directory before you
271 do a "make modules_install". 289 do a "make modules_install".
272 290
273 Alternatively, before compiling, use the kernel config option 291 Alternatively, before compiling, use the kernel config option
274 "LOCALVERSION" to append a unique suffix to the regular kernel version. 292 "LOCALVERSION" to append a unique suffix to the regular kernel version.
275 LOCALVERSION can be set in the "General Setup" menu. 293 LOCALVERSION can be set in the "General Setup" menu.
276 294
277 - In order to boot your new kernel, you'll need to copy the kernel 295 - In order to boot your new kernel, you'll need to copy the kernel
278 image (e.g. .../linux/arch/i386/boot/bzImage after compilation) 296 image (e.g. .../linux/arch/i386/boot/bzImage after compilation)
279 to the place where your regular bootable kernel is found. 297 to the place where your regular bootable kernel is found.
280 298
281 - Booting a kernel directly from a floppy without the assistance of a 299 - Booting a kernel directly from a floppy without the assistance of a
282 bootloader such as LILO, is no longer supported. 300 bootloader such as LILO, is no longer supported.
283 301
284 If you boot Linux from the hard drive, chances are you use LILO, which 302 If you boot Linux from the hard drive, chances are you use LILO, which
285 uses the kernel image as specified in the file /etc/lilo.conf. The 303 uses the kernel image as specified in the file /etc/lilo.conf. The
286 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or 304 kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
287 /boot/bzImage. To use the new kernel, save a copy of the old image 305 /boot/bzImage. To use the new kernel, save a copy of the old image
288 and copy the new image over the old one. Then, you MUST RERUN LILO 306 and copy the new image over the old one. Then, you MUST RERUN LILO
289 to update the loading map!! If you don't, you won't be able to boot 307 to update the loading map!! If you don't, you won't be able to boot
290 the new kernel image. 308 the new kernel image.
291 309
292 Reinstalling LILO is usually a matter of running /sbin/lilo. 310 Reinstalling LILO is usually a matter of running /sbin/lilo.
293 You may wish to edit /etc/lilo.conf to specify an entry for your 311 You may wish to edit /etc/lilo.conf to specify an entry for your
294 old kernel image (say, /vmlinux.old) in case the new one does not 312 old kernel image (say, /vmlinux.old) in case the new one does not
295 work. See the LILO docs for more information. 313 work. See the LILO docs for more information.
296 314
297 After reinstalling LILO, you should be all set. Shutdown the system, 315 After reinstalling LILO, you should be all set. Shutdown the system,
298 reboot, and enjoy! 316 reboot, and enjoy!
299 317
300 If you ever need to change the default root device, video mode, 318 If you ever need to change the default root device, video mode,
301 ramdisk size, etc. in the kernel image, use the 'rdev' program (or 319 ramdisk size, etc. in the kernel image, use the 'rdev' program (or
302 alternatively the LILO boot options when appropriate). No need to 320 alternatively the LILO boot options when appropriate). No need to
303 recompile the kernel to change these parameters. 321 recompile the kernel to change these parameters.
304 322
305 - Reboot with the new kernel and enjoy. 323 - Reboot with the new kernel and enjoy.
306 324
307 IF SOMETHING GOES WRONG: 325 IF SOMETHING GOES WRONG:
308 326
309 - If you have problems that seem to be due to kernel bugs, please check 327 - If you have problems that seem to be due to kernel bugs, please check
310 the file MAINTAINERS to see if there is a particular person associated 328 the file MAINTAINERS to see if there is a particular person associated
311 with the part of the kernel that you are having trouble with. If there 329 with the part of the kernel that you are having trouble with. If there
312 isn't anyone listed there, then the second best thing is to mail 330 isn't anyone listed there, then the second best thing is to mail
313 them to me (torvalds@linux-foundation.org), and possibly to any other 331 them to me (torvalds@linux-foundation.org), and possibly to any other
314 relevant mailing-list or to the newsgroup. 332 relevant mailing-list or to the newsgroup.
315 333
316 - In all bug-reports, *please* tell what kernel you are talking about, 334 - In all bug-reports, *please* tell what kernel you are talking about,
317 how to duplicate the problem, and what your setup is (use your common 335 how to duplicate the problem, and what your setup is (use your common
318 sense). If the problem is new, tell me so, and if the problem is 336 sense). If the problem is new, tell me so, and if the problem is
319 old, please try to tell me when you first noticed it. 337 old, please try to tell me when you first noticed it.
320 338
321 - If the bug results in a message like 339 - If the bug results in a message like
322 340
323 unable to handle kernel paging request at address C0000010 341 unable to handle kernel paging request at address C0000010
324 Oops: 0002 342 Oops: 0002
325 EIP: 0010:XXXXXXXX 343 EIP: 0010:XXXXXXXX
326 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx 344 eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx
327 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx 345 esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx
328 ds: xxxx es: xxxx fs: xxxx gs: xxxx 346 ds: xxxx es: xxxx fs: xxxx gs: xxxx
329 Pid: xx, process nr: xx 347 Pid: xx, process nr: xx
330 xx xx xx xx xx xx xx xx xx xx 348 xx xx xx xx xx xx xx xx xx xx
331 349
332 or similar kernel debugging information on your screen or in your 350 or similar kernel debugging information on your screen or in your
333 system log, please duplicate it *exactly*. The dump may look 351 system log, please duplicate it *exactly*. The dump may look
334 incomprehensible to you, but it does contain information that may 352 incomprehensible to you, but it does contain information that may
335 help debugging the problem. The text above the dump is also 353 help debugging the problem. The text above the dump is also
336 important: it tells something about why the kernel dumped code (in 354 important: it tells something about why the kernel dumped code (in
337 the above example, it's due to a bad kernel pointer). More information 355 the above example, it's due to a bad kernel pointer). More information
338 on making sense of the dump is in Documentation/oops-tracing.txt 356 on making sense of the dump is in Documentation/oops-tracing.txt
339 357
340 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump 358 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
341 as is, otherwise you will have to use the "ksymoops" program to make 359 as is, otherwise you will have to use the "ksymoops" program to make
342 sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred). 360 sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
343 This utility can be downloaded from 361 This utility can be downloaded from
344 ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ . 362 ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
345 Alternatively, you can do the dump lookup by hand: 363 Alternatively, you can do the dump lookup by hand:
346 364
347 - In debugging dumps like the above, it helps enormously if you can 365 - In debugging dumps like the above, it helps enormously if you can
348 look up what the EIP value means. The hex value as such doesn't help 366 look up what the EIP value means. The hex value as such doesn't help
349 me or anybody else very much: it will depend on your particular 367 me or anybody else very much: it will depend on your particular
350 kernel setup. What you should do is take the hex value from the EIP 368 kernel setup. What you should do is take the hex value from the EIP
351 line (ignore the "0010:"), and look it up in the kernel namelist to 369 line (ignore the "0010:"), and look it up in the kernel namelist to
352 see which kernel function contains the offending address. 370 see which kernel function contains the offending address.
353 371
354 To find out the kernel function name, you'll need to find the system 372 To find out the kernel function name, you'll need to find the system
355 binary associated with the kernel that exhibited the symptom. This is 373 binary associated with the kernel that exhibited the symptom. This is
356 the file 'linux/vmlinux'. To extract the namelist and match it against 374 the file 'linux/vmlinux'. To extract the namelist and match it against
357 the EIP from the kernel crash, do: 375 the EIP from the kernel crash, do:
358 376
359 nm vmlinux | sort | less 377 nm vmlinux | sort | less
360 378
361 This will give you a list of kernel addresses sorted in ascending 379 This will give you a list of kernel addresses sorted in ascending
362 order, from which it is simple to find the function that contains the 380 order, from which it is simple to find the function that contains the
363 offending address. Note that the address given by the kernel 381 offending address. Note that the address given by the kernel
364 debugging messages will not necessarily match exactly with the 382 debugging messages will not necessarily match exactly with the
365 function addresses (in fact, that is very unlikely), so you can't 383 function addresses (in fact, that is very unlikely), so you can't
366 just 'grep' the list: the list will, however, give you the starting 384 just 'grep' the list: the list will, however, give you the starting
367 point of each kernel function, so by looking for the function that 385 point of each kernel function, so by looking for the function that
368 has a starting address lower than the one you are searching for but 386 has a starting address lower than the one you are searching for but
369 is followed by a function with a higher address you will find the one 387 is followed by a function with a higher address you will find the one
370 you want. In fact, it may be a good idea to include a bit of 388 you want. In fact, it may be a good idea to include a bit of
371 "context" in your problem report, giving a few lines around the 389 "context" in your problem report, giving a few lines around the
372 interesting one. 390 interesting one.
373 391
374 If you for some reason cannot do the above (you have a pre-compiled 392 If you for some reason cannot do the above (you have a pre-compiled
375 kernel image or similar), telling me as much about your setup as 393 kernel image or similar), telling me as much about your setup as
376 possible will help. Please read the REPORTING-BUGS document for details. 394 possible will help. Please read the REPORTING-BUGS document for details.
377 395
378 - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you 396 - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
379 cannot change values or set break points.) To do this, first compile the 397 cannot change values or set break points.) To do this, first compile the
380 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make 398 kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
381 clean". You'll also need to enable CONFIG_PROC_FS (via "make config"). 399 clean". You'll also need to enable CONFIG_PROC_FS (via "make config").
382 400
383 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore". 401 After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
384 You can now use all the usual gdb commands. The command to look up the 402 You can now use all the usual gdb commands. The command to look up the
385 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes 403 point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
386 with the EIP value.) 404 with the EIP value.)
387 405
388 gdb'ing a non-running kernel currently fails because gdb (wrongly) 406 gdb'ing a non-running kernel currently fails because gdb (wrongly)
389 disregards the starting offset for which the kernel is compiled. 407 disregards the starting offset for which the kernel is compiled.
390 408
391 409