diff options
| author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-09-21 08:51:11 -0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-10-24 06:12:35 -0400 |
| commit | 9d85025b0418163fae079c9ba8f8445212de8568 (patch) | |
| tree | 4629e2dedf4a9ed45a6855c129101f9b52138372 /README | |
| parent | 186128f75392f8478ad1b32a675627d738881ca4 (diff) | |
docs-rst: create an user's manual book
Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters
on an user's manual book.
As we'll be numbering the user's manual, remove the manual
numbering from SecurityBugs.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'README')
| -rw-r--r-- | README | 411 |
1 files changed, 0 insertions, 411 deletions
diff --git a/README b/README deleted file mode 100644 index 3335b3b2973a..000000000000 --- a/README +++ /dev/null | |||
| @@ -1,411 +0,0 @@ | |||
| 1 | Linux kernel release 4.x <http://kernel.org/> | ||
| 2 | ============================================= | ||
| 3 | |||
| 4 | These are the release notes for Linux version 4. 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. | ||
| 7 | |||
| 8 | What is Linux? | ||
| 9 | -------------- | ||
| 10 | |||
| 11 | Linux is a clone of the operating system Unix, written from scratch by | ||
| 12 | Linus Torvalds with assistance from a loosely-knit team of hackers across | ||
| 13 | the Net. It aims towards POSIX and Single UNIX Specification compliance. | ||
| 14 | |||
| 15 | It has all the features you would expect in a modern fully-fledged Unix, | ||
| 16 | including true multitasking, virtual memory, shared libraries, demand | ||
| 17 | loading, shared copy-on-write executables, proper memory management, | ||
| 18 | and multistack networking including IPv4 and IPv6. | ||
| 19 | |||
| 20 | It is distributed under the GNU General Public License - see the | ||
| 21 | accompanying COPYING file for more details. | ||
| 22 | |||
| 23 | On what hardware does it run? | ||
| 24 | ----------------------------- | ||
| 25 | |||
| 26 | Although originally developed first for 32-bit x86-based PCs (386 or higher), | ||
| 27 | today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and | ||
| 28 | UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell, | ||
| 29 | IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS, | ||
| 30 | Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures. | ||
| 31 | |||
| 32 | Linux is easily portable to most general-purpose 32- or 64-bit architectures | ||
| 33 | as long as they have a paged memory management unit (PMMU) and a port of the | ||
| 34 | GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has | ||
| 35 | also been ported to a number of architectures without a PMMU, although | ||
| 36 | functionality is then obviously somewhat limited. | ||
| 37 | Linux has also been ported to itself. You can now run the kernel as a | ||
| 38 | userspace application - this is called UserMode Linux (UML). | ||
| 39 | |||
| 40 | Documentation | ||
| 41 | ------------- | ||
| 42 | |||
| 43 | - There is a lot of documentation available both in electronic form on | ||
| 44 | the Internet and in books, both Linux-specific and pertaining to | ||
| 45 | general UNIX questions. I'd recommend looking into the documentation | ||
| 46 | subdirectories on any Linux FTP site for the LDP (Linux Documentation | ||
| 47 | Project) books. This README is not meant to be documentation on the | ||
| 48 | system: there are much better sources available. | ||
| 49 | |||
| 50 | - There are various README files in the Documentation/ subdirectory: | ||
| 51 | these typically contain kernel-specific installation notes for some | ||
| 52 | drivers for example. See Documentation/00-INDEX for a list of what | ||
| 53 | is contained in each file. Please read the Changes file, as it | ||
| 54 | contains information about the problems, which may result by upgrading | ||
| 55 | your kernel. | ||
| 56 | |||
| 57 | - The Documentation/DocBook/ subdirectory contains several guides for | ||
| 58 | kernel developers and users. These guides can be rendered in a | ||
| 59 | number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others. | ||
| 60 | After installation, ``make psdocs``, ``make pdfdocs``, ``make htmldocs``, | ||
| 61 | or ``make mandocs`` will render the documentation in the requested format. | ||
| 62 | |||
| 63 | Installing the kernel source | ||
| 64 | ---------------------------- | ||
| 65 | |||
| 66 | - If you install the full sources, put the kernel tarball in a | ||
| 67 | directory where you have permissions (e.g. your home directory) and | ||
| 68 | unpack it:: | ||
| 69 | |||
| 70 | xz -cd linux-4.X.tar.xz | tar xvf - | ||
| 71 | |||
| 72 | Replace "X" with the version number of the latest kernel. | ||
| 73 | |||
| 74 | Do NOT use the /usr/src/linux area! This area has a (usually | ||
| 75 | incomplete) set of kernel headers that are used by the library header | ||
| 76 | files. They should match the library, and not get messed up by | ||
| 77 | whatever the kernel-du-jour happens to be. | ||
| 78 | |||
| 79 | - You can also upgrade between 4.x releases by patching. Patches are | ||
| 80 | distributed in the xz format. To install by patching, get all the | ||
| 81 | newer patch files, enter the top level directory of the kernel source | ||
| 82 | (linux-4.X) and execute:: | ||
| 83 | |||
| 84 | xz -cd ../patch-4.x.xz | patch -p1 | ||
| 85 | |||
| 86 | Replace "x" for all versions bigger than the version "X" of your current | ||
| 87 | source tree, **in_order**, and you should be ok. You may want to remove | ||
| 88 | the backup files (some-file-name~ or some-file-name.orig), and make sure | ||
| 89 | that there are no failed patches (some-file-name# or some-file-name.rej). | ||
| 90 | If there are, either you or I have made a mistake. | ||
| 91 | |||
| 92 | Unlike patches for the 4.x kernels, patches for the 4.x.y kernels | ||
| 93 | (also known as the -stable kernels) are not incremental but instead apply | ||
| 94 | directly to the base 4.x kernel. For example, if your base kernel is 4.0 | ||
| 95 | and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1 | ||
| 96 | and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and | ||
| 97 | want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is, | ||
| 98 | patch -R) **before** applying the 4.0.3 patch. You can read more on this in | ||
| 99 | :ref:`Documentation/applying-patches.txt <applying_patches>`. | ||
| 100 | |||
| 101 | Alternatively, the script patch-kernel can be used to automate this | ||
| 102 | process. It determines the current kernel version and applies any | ||
| 103 | patches found:: | ||
| 104 | |||
| 105 | linux/scripts/patch-kernel linux | ||
| 106 | |||
| 107 | The first argument in the command above is the location of the | ||
| 108 | kernel source. Patches are applied from the current directory, but | ||
| 109 | an alternative directory can be specified as the second argument. | ||
| 110 | |||
| 111 | - Make sure you have no stale .o files and dependencies lying around:: | ||
| 112 | |||
| 113 | cd linux | ||
| 114 | make mrproper | ||
| 115 | |||
| 116 | You should now have the sources correctly installed. | ||
| 117 | |||
| 118 | Software requirements | ||
| 119 | --------------------- | ||
| 120 | |||
| 121 | Compiling and running the 4.x kernels requires up-to-date | ||
| 122 | versions of various software packages. Consult | ||
| 123 | :ref:`Documentation/Changes <changes>` for the minimum version numbers | ||
| 124 | required and how to get updates for these packages. Beware that using | ||
| 125 | excessively old versions of these packages can cause indirect | ||
| 126 | errors that are very difficult to track down, so don't assume that | ||
| 127 | you can just update packages when obvious problems arise during | ||
| 128 | build or operation. | ||
| 129 | |||
| 130 | Build directory for the kernel | ||
| 131 | ------------------------------ | ||
| 132 | |||
| 133 | When compiling the kernel, all output files will per default be | ||
| 134 | stored together with the kernel source code. | ||
| 135 | Using the option ``make O=output/dir`` allows you to specify an alternate | ||
| 136 | place for the output files (including .config). | ||
| 137 | Example:: | ||
| 138 | |||
| 139 | kernel source code: /usr/src/linux-4.X | ||
| 140 | build directory: /home/name/build/kernel | ||
| 141 | |||
| 142 | To configure and build the kernel, use:: | ||
| 143 | |||
| 144 | cd /usr/src/linux-4.X | ||
| 145 | make O=/home/name/build/kernel menuconfig | ||
| 146 | make O=/home/name/build/kernel | ||
| 147 | sudo make O=/home/name/build/kernel modules_install install | ||
| 148 | |||
| 149 | Please note: If the ``O=output/dir`` option is used, then it must be | ||
| 150 | used for all invocations of make. | ||
| 151 | |||
| 152 | Configuring the kernel | ||
| 153 | ---------------------- | ||
| 154 | |||
| 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 | ||
| 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 | ||
| 159 | new version with minimal work, use ``make oldconfig``, which will | ||
| 160 | only ask you for the answers to new questions. | ||
| 161 | |||
| 162 | - Alternative configuration commands are:: | ||
| 163 | |||
| 164 | "make config" Plain text interface. | ||
| 165 | |||
| 166 | "make menuconfig" Text based color menus, radiolists & dialogs. | ||
| 167 | |||
| 168 | "make nconfig" Enhanced text based color menus. | ||
| 169 | |||
| 170 | "make xconfig" Qt based configuration tool. | ||
| 171 | |||
| 172 | "make gconfig" GTK+ based configuration tool. | ||
| 173 | |||
| 174 | "make oldconfig" Default all questions based on the contents of | ||
| 175 | your existing ./.config file and asking about | ||
| 176 | new config symbols. | ||
| 177 | |||
| 178 | "make silentoldconfig" | ||
| 179 | Like above, but avoids cluttering the screen | ||
| 180 | with questions already answered. | ||
| 181 | Additionally updates the dependencies. | ||
| 182 | |||
| 183 | "make olddefconfig" | ||
| 184 | Like above, but sets new symbols to their default | ||
| 185 | values without prompting. | ||
| 186 | |||
| 187 | "make defconfig" Create a ./.config file by using the default | ||
| 188 | symbol values from either arch/$ARCH/defconfig | ||
| 189 | or arch/$ARCH/configs/${PLATFORM}_defconfig, | ||
| 190 | depending on the architecture. | ||
| 191 | |||
| 192 | "make ${PLATFORM}_defconfig" | ||
| 193 | Create a ./.config file by using the default | ||
| 194 | symbol values from | ||
| 195 | arch/$ARCH/configs/${PLATFORM}_defconfig. | ||
| 196 | Use "make help" to get a list of all available | ||
| 197 | platforms of your architecture. | ||
| 198 | |||
| 199 | "make allyesconfig" | ||
| 200 | Create a ./.config file by setting symbol | ||
| 201 | values to 'y' as much as possible. | ||
| 202 | |||
| 203 | "make allmodconfig" | ||
| 204 | Create a ./.config file by setting symbol | ||
| 205 | values to 'm' as much as possible. | ||
| 206 | |||
| 207 | "make allnoconfig" Create a ./.config file by setting symbol | ||
| 208 | values to 'n' as much as possible. | ||
| 209 | |||
| 210 | "make randconfig" Create a ./.config file by setting symbol | ||
| 211 | values to random values. | ||
| 212 | |||
| 213 | "make localmodconfig" Create a config based on current config and | ||
| 214 | loaded modules (lsmod). Disables any module | ||
| 215 | option that is not needed for the loaded modules. | ||
| 216 | |||
| 217 | To create a localmodconfig for another machine, | ||
| 218 | store the lsmod of that machine into a file | ||
| 219 | and pass it in as a LSMOD parameter. | ||
| 220 | |||
| 221 | target$ lsmod > /tmp/mylsmod | ||
| 222 | target$ scp /tmp/mylsmod host:/tmp | ||
| 223 | |||
| 224 | host$ make LSMOD=/tmp/mylsmod localmodconfig | ||
| 225 | |||
| 226 | The above also works when cross compiling. | ||
| 227 | |||
| 228 | "make localyesconfig" Similar to localmodconfig, except it will convert | ||
| 229 | all module options to built in (=y) options. | ||
| 230 | |||
| 231 | You can find more information on using the Linux kernel config tools | ||
| 232 | in Documentation/kbuild/kconfig.txt. | ||
| 233 | |||
| 234 | - NOTES on ``make config``: | ||
| 235 | |||
| 236 | - Having unnecessary drivers will make the kernel bigger, and can | ||
| 237 | under some circumstances lead to problems: probing for a | ||
| 238 | nonexistent controller card may confuse your other controllers | ||
| 239 | |||
| 240 | - A kernel with math-emulation compiled in will still use the | ||
| 241 | coprocessor if one is present: the math emulation will just | ||
| 242 | never get used in that case. The kernel will be slightly larger, | ||
| 243 | but will work on different machines regardless of whether they | ||
| 244 | have a math coprocessor or not. | ||
| 245 | |||
| 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 "development", | ||
| 251 | "experimental", or "debugging" features. | ||
| 252 | |||
| 253 | Compiling the kernel | ||
| 254 | -------------------- | ||
| 255 | |||
| 256 | - Make sure you have at least gcc 3.2 available. | ||
| 257 | For more information, refer to :ref:`Documentation/Changes <changes>`. | ||
| 258 | |||
| 259 | Please note that you can still run a.out user programs with this kernel. | ||
| 260 | |||
| 261 | - Do a ``make`` to create a compressed kernel image. It is also | ||
| 262 | possible to do ``make install`` if you have lilo installed to suit the | ||
| 263 | kernel makefiles, but you may want to check your particular lilo setup first. | ||
| 264 | |||
| 265 | To do the actual install, you have to be root, but none of the normal | ||
| 266 | build should require that. Don't take the name of root in vain. | ||
| 267 | |||
| 268 | - If you configured any of the parts of the kernel as ``modules``, you | ||
| 269 | will also have to do ``make modules_install``. | ||
| 270 | |||
| 271 | - Verbose kernel compile/build output: | ||
| 272 | |||
| 273 | Normally, the kernel build system runs in a fairly quiet mode (but not | ||
| 274 | totally silent). However, sometimes you or other kernel developers need | ||
| 275 | to see compile, link, or other commands exactly as they are executed. | ||
| 276 | For this, use "verbose" build mode. This is done by passing | ||
| 277 | ``V=1`` to the ``make`` command, e.g.:: | ||
| 278 | |||
| 279 | make V=1 all | ||
| 280 | |||
| 281 | To have the build system also tell the reason for the rebuild of each | ||
| 282 | target, use ``V=2``. The default is ``V=0``. | ||
| 283 | |||
| 284 | - Keep a backup kernel handy in case something goes wrong. This is | ||
| 285 | especially true for the development releases, since each new release | ||
| 286 | contains new code which has not been debugged. Make sure you keep a | ||
| 287 | backup of the modules corresponding to that kernel, as well. If you | ||
| 288 | are installing a new kernel with the same version number as your | ||
| 289 | working kernel, make a backup of your modules directory before you | ||
| 290 | do a ``make modules_install``. | ||
| 291 | |||
| 292 | Alternatively, before compiling, use the kernel config option | ||
| 293 | "LOCALVERSION" to append a unique suffix to the regular kernel version. | ||
| 294 | LOCALVERSION can be set in the "General Setup" menu. | ||
| 295 | |||
| 296 | - In order to boot your new kernel, you'll need to copy the kernel | ||
| 297 | image (e.g. .../linux/arch/x86/boot/bzImage after compilation) | ||
| 298 | to the place where your regular bootable kernel is found. | ||
| 299 | |||
| 300 | - Booting a kernel directly from a floppy without the assistance of a | ||
| 301 | bootloader such as LILO, is no longer supported. | ||
| 302 | |||
| 303 | If you boot Linux from the hard drive, chances are you use LILO, which | ||
| 304 | uses the kernel image as specified in the file /etc/lilo.conf. The | ||
| 305 | kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or | ||
| 306 | /boot/bzImage. To use the new kernel, save a copy of the old image | ||
| 307 | and copy the new image over the old one. Then, you MUST RERUN LILO | ||
| 308 | to update the loading map! If you don't, you won't be able to boot | ||
| 309 | the new kernel image. | ||
| 310 | |||
| 311 | Reinstalling LILO is usually a matter of running /sbin/lilo. | ||
| 312 | You may wish to edit /etc/lilo.conf to specify an entry for your | ||
| 313 | old kernel image (say, /vmlinux.old) in case the new one does not | ||
| 314 | work. See the LILO docs for more information. | ||
| 315 | |||
| 316 | After reinstalling LILO, you should be all set. Shutdown the system, | ||
| 317 | reboot, and enjoy! | ||
| 318 | |||
| 319 | If you ever need to change the default root device, video mode, | ||
| 320 | ramdisk size, etc. in the kernel image, use the ``rdev`` program (or | ||
| 321 | alternatively the LILO boot options when appropriate). No need to | ||
| 322 | recompile the kernel to change these parameters. | ||
| 323 | |||
| 324 | - Reboot with the new kernel and enjoy. | ||
| 325 | |||
| 326 | If something goes wrong | ||
| 327 | ----------------------- | ||
| 328 | |||
| 329 | - If you have problems that seem to be due to kernel bugs, please check | ||
| 330 | the file MAINTAINERS to see if there is a particular person associated | ||
| 331 | with the part of the kernel that you are having trouble with. If there | ||
| 332 | isn't anyone listed there, then the second best thing is to mail | ||
| 333 | them to me (torvalds@linux-foundation.org), and possibly to any other | ||
| 334 | relevant mailing-list or to the newsgroup. | ||
| 335 | |||
| 336 | - In all bug-reports, *please* tell what kernel you are talking about, | ||
| 337 | how to duplicate the problem, and what your setup is (use your common | ||
| 338 | sense). If the problem is new, tell me so, and if the problem is | ||
| 339 | old, please try to tell me when you first noticed it. | ||
| 340 | |||
| 341 | - If the bug results in a message like:: | ||
| 342 | |||
| 343 | unable to handle kernel paging request at address C0000010 | ||
| 344 | Oops: 0002 | ||
| 345 | EIP: 0010:XXXXXXXX | ||
| 346 | eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx | ||
| 347 | esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx | ||
| 348 | ds: xxxx es: xxxx fs: xxxx gs: xxxx | ||
| 349 | Pid: xx, process nr: xx | ||
| 350 | xx xx xx xx xx xx xx xx xx xx | ||
| 351 | |||
| 352 | or similar kernel debugging information on your screen or in your | ||
| 353 | system log, please duplicate it *exactly*. The dump may look | ||
| 354 | incomprehensible to you, but it does contain information that may | ||
| 355 | help debugging the problem. The text above the dump is also | ||
| 356 | important: it tells something about why the kernel dumped code (in | ||
| 357 | the above example, it's due to a bad kernel pointer). More information | ||
| 358 | on making sense of the dump is in Documentation/oops-tracing.txt | ||
| 359 | |||
| 360 | - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump | ||
| 361 | as is, otherwise you will have to use the ``ksymoops`` program to make | ||
| 362 | sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred). | ||
| 363 | This utility can be downloaded from | ||
| 364 | ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ . | ||
| 365 | Alternatively, you can do the dump lookup by hand: | ||
| 366 | |||
| 367 | - In debugging dumps like the above, it helps enormously if you can | ||
| 368 | look up what the EIP value means. The hex value as such doesn't help | ||
| 369 | me or anybody else very much: it will depend on your particular | ||
| 370 | kernel setup. What you should do is take the hex value from the EIP | ||
| 371 | line (ignore the ``0010:``), and look it up in the kernel namelist to | ||
| 372 | see which kernel function contains the offending address. | ||
| 373 | |||
| 374 | To find out the kernel function name, you'll need to find the system | ||
| 375 | binary associated with the kernel that exhibited the symptom. This is | ||
| 376 | the file 'linux/vmlinux'. To extract the namelist and match it against | ||
| 377 | the EIP from the kernel crash, do:: | ||
| 378 | |||
| 379 | nm vmlinux | sort | less | ||
| 380 | |||
| 381 | This will give you a list of kernel addresses sorted in ascending | ||
| 382 | order, from which it is simple to find the function that contains the | ||
| 383 | offending address. Note that the address given by the kernel | ||
| 384 | debugging messages will not necessarily match exactly with the | ||
| 385 | function addresses (in fact, that is very unlikely), so you can't | ||
| 386 | just 'grep' the list: the list will, however, give you the starting | ||
| 387 | point of each kernel function, so by looking for the function that | ||
| 388 | has a starting address lower than the one you are searching for but | ||
| 389 | is followed by a function with a higher address you will find the one | ||
| 390 | you want. In fact, it may be a good idea to include a bit of | ||
| 391 | "context" in your problem report, giving a few lines around the | ||
| 392 | interesting one. | ||
| 393 | |||
| 394 | If you for some reason cannot do the above (you have a pre-compiled | ||
| 395 | kernel image or similar), telling me as much about your setup as | ||
| 396 | possible will help. Please read the :ref:`REPORTING-BUGS <reportingbugs>` | ||
| 397 | document for details. | ||
| 398 | |||
| 399 | - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you | ||
| 400 | cannot change values or set break points.) To do this, first compile the | ||
| 401 | kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make | ||
| 402 | clean``. You'll also need to enable CONFIG_PROC_FS (via ``make config``). | ||
| 403 | |||
| 404 | After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``. | ||
| 405 | You can now use all the usual gdb commands. The command to look up the | ||
| 406 | point where your system crashed is ``l *0xXXXXXXXX``. (Replace the XXXes | ||
| 407 | with the EIP value.) | ||
| 408 | |||
| 409 | gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly) | ||
| 410 | disregards the starting offset for which the kernel is compiled. | ||
| 411 | |||
