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chandramouli narayanan 22cddcc7df crypto: aes - AES CTR x86_64 "by8" AVX optimization 
This patch introduces "by8" AES CTR mode AVX optimization inspired by
Intel Optimized IPSEC Cryptograhpic library. For additional information,
please see:
http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=22972

The functions aes_ctr_enc_128_avx_by8(), aes_ctr_enc_192_avx_by8() and
aes_ctr_enc_256_avx_by8() are adapted from
Intel Optimized IPSEC Cryptographic library. When both AES and AVX features
are enabled in a platform, the glue code in AESNI module overrieds the
existing "by4" CTR mode en/decryption with the "by8"
AES CTR mode en/decryption.

On a Haswell desktop, with turbo disabled and all cpus running
at maximum frequency, the "by8" CTR mode optimization
shows better performance results across data & key sizes
as measured by tcrypt.

The average performance improvement of the "by8" version over the "by4"
version is as follows:

For 128 bit key and data sizes >= 256 bytes, there is a 10-16% improvement.
For 192 bit key and data sizes >= 256 bytes, there is a 20-22% improvement.
For 256 bit key and data sizes >= 256 bytes, there is a 20-25% improvement.

A typical run of tcrypt with AES CTR mode encryption of the "by4" and "by8"
optimization shows the following results:

tcrypt with "by4" AES CTR mode encryption optimization on a Haswell Desktop:
---------------------------------------------------------------------------

testing speed of __ctr-aes-aesni encryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 343 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 336 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 491 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1130 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 7309 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 346 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 361 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 543 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1321 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 9649 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 369 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 366 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 595 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1531 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 10522 cycles (8192 bytes)

testing speed of __ctr-aes-aesni decryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 336 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 350 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 487 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1129 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 7287 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 350 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 359 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 635 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1324 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 9595 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 364 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 377 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 604 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1527 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 10549 cycles (8192 bytes)

tcrypt with "by8" AES CTR mode encryption optimization on a Haswell Desktop:
---------------------------------------------------------------------------

testing speed of __ctr-aes-aesni encryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 340 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 330 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 450 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1043 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 6597 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 339 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 352 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 539 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1153 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 8458 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 353 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 360 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 512 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1277 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 8745 cycles (8192 bytes)

testing speed of __ctr-aes-aesni decryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 348 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 335 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 451 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1030 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 6611 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 354 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 346 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 488 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1154 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 8390 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 357 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 362 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 515 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1284 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 8681 cycles (8192 bytes)

crypto: Incorporate feed back to AES CTR mode optimization patch

Specifically, the following:
a) alignment around main loop in aes_ctrby8_avx_x86_64.S
b) .rodata around data constants used in the assembely code.
c) the use of CONFIG_AVX in the glue code.
d) fix up white space.
e) informational message for "by8" AES CTR mode optimization
f) "by8" AES CTR mode optimization can be simply enabled
if the platform supports both AES and AVX features. The
optimization works superbly on Sandybridge as well.

Testing on Haswell shows no performance change since the last.

Testing on Sandybridge shows that the "by8" AES CTR mode optimization
greatly improves performance.

tcrypt log with "by4" AES CTR mode optimization on Sandybridge
--------------------------------------------------------------

testing speed of __ctr-aes-aesni encryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 383 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 408 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 707 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1864 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 12813 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 395 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 432 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 780 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 2132 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 15765 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 416 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 438 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 842 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 2383 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 16945 cycles (8192 bytes)

testing speed of __ctr-aes-aesni decryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 389 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 409 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 704 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1865 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 12783 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 409 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 434 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 792 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 2151 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 15804 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 421 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 444 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 840 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 2394 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 16928 cycles (8192 bytes)

tcrypt log with "by8" AES CTR mode optimization on Sandybridge
--------------------------------------------------------------

testing speed of __ctr-aes-aesni encryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 383 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 401 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 522 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1136 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 7046 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 394 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 418 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 559 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1263 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 9072 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 408 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 428 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 595 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1385 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 9224 cycles (8192 bytes)

testing speed of __ctr-aes-aesni decryption
test 0 (128 bit key, 16 byte blocks): 1 operation in 390 cycles (16 bytes)
test 1 (128 bit key, 64 byte blocks): 1 operation in 402 cycles (64 bytes)
test 2 (128 bit key, 256 byte blocks): 1 operation in 530 cycles (256 bytes)
test 3 (128 bit key, 1024 byte blocks): 1 operation in 1135 cycles (1024 bytes)
test 4 (128 bit key, 8192 byte blocks): 1 operation in 7079 cycles (8192 bytes)
test 5 (192 bit key, 16 byte blocks): 1 operation in 414 cycles (16 bytes)
test 6 (192 bit key, 64 byte blocks): 1 operation in 417 cycles (64 bytes)
test 7 (192 bit key, 256 byte blocks): 1 operation in 572 cycles (256 bytes)
test 8 (192 bit key, 1024 byte blocks): 1 operation in 1312 cycles (1024 bytes)
test 9 (192 bit key, 8192 byte blocks): 1 operation in 9073 cycles (8192 bytes)
test 10 (256 bit key, 16 byte blocks): 1 operation in 415 cycles (16 bytes)
test 11 (256 bit key, 64 byte blocks): 1 operation in 454 cycles (64 bytes)
test 12 (256 bit key, 256 byte blocks): 1 operation in 598 cycles (256 bytes)
test 13 (256 bit key, 1024 byte blocks): 1 operation in 1407 cycles (1024 bytes)
test 14 (256 bit key, 8192 byte blocks): 1 operation in 9288 cycles (8192 bytes)

crypto: Fix redundant checks

a) Fix the redundant check for cpu_has_aes
b) Fix the key length check when invoking the CTR mode "by8"
encryptor/decryptor.

crypto: fix typo in AES ctr mode transform

Signed-off-by: Chandramouli Narayanan <mouli@linux.intel.com>
Reviewed-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
 		2014-06-20 21:27:58 +08:00
Documentation crypto: qat - Update to makefiles 2014-06-20 21:26:19 +08:00
arch crypto: aes - AES CTR x86_64 "by8" AVX optimization 2014-06-20 21:27:58 +08:00
block Merge git://git.infradead.org/users/willy/linux-nvme 2014-06-15 15:58:03 -10:00
crypto crypto: des_3des - add x86-64 assembly implementation 2014-06-20 21:27:58 +08:00
drivers crypto: caam - remove duplicate FIFOST_CONT_MASK define 2014-06-20 21:27:57 +08:00
firmware Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2014-06-12 21:23:38 -07:00
fs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2014-06-14 19:48:43 -05:00
include crypto: des_3des - add x86-64 assembly implementation 2014-06-20 21:27:58 +08:00
init
…
ipc
…
kernel One bug fix that goes back to 3.10. Accessing a non existent buffer 2014-06-12 21:07:25 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-06-12 14:27:40 -07:00
mm fix __swap_writepage() compile failure on old gcc versions 2014-06-14 19:30:48 -05:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-06-15 16:37:03 -10:00
samples
…
scripts Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2014-06-12 21:29:20 -07:00
security Merge branch 'serge-next-2' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-security 2014-06-13 07:39:39 -07:00
sound sound fixes for 3.16-rc1 2014-06-13 07:42:49 -07:00
tools Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2014-06-12 20:11:38 -07:00
usr
…
virt/kvm Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-06-12 19:42:15 -07:00
.gitignore
…
.mailmap
…
COPYING
…
CREDITS
…
Kbuild
…
Kconfig
…
MAINTAINERS crypto: qat - Update to makefiles 2014-06-20 21:26:19 +08:00
Makefile Linux 3.16-rc1 2014-06-15 17:45:28 -10:00
README
…
REPORTING-BUGS
…

README 

        Linux kernel release 3.x <http://kernel.org/>

These are the release notes for Linux version 3.  Read them carefully,
as they tell you what this is all about, explain how to install the
kernel, and what to do if something goes wrong. 

WHAT IS LINUX?

  Linux is a clone of the operating system Unix, written from scratch by
  Linus Torvalds with assistance from a loosely-knit team of hackers across
  the Net. It aims towards POSIX and Single UNIX Specification compliance.

  It has all the features you would expect in a modern fully-fledged Unix,
  including true multitasking, virtual memory, shared libraries, demand
  loading, shared copy-on-write executables, proper memory management,
  and multistack networking including IPv4 and IPv6.

  It is distributed under the GNU General Public License - see the
  accompanying COPYING file for more details. 

ON WHAT HARDWARE DOES IT RUN?

  Although originally developed first for 32-bit x86-based PCs (386 or higher),
  today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
  UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
  IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
  Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures.

  Linux is easily portable to most general-purpose 32- or 64-bit architectures
  as long as they have a paged memory management unit (PMMU) and a port of the
  GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
  also been ported to a number of architectures without a PMMU, although
  functionality is then obviously somewhat limited.
  Linux has also been ported to itself. You can now run the kernel as a
  userspace application - this is called UserMode Linux (UML).

DOCUMENTATION:

 - There is a lot of documentation available both in electronic form on
   the Internet and in books, both Linux-specific and pertaining to
   general UNIX questions.  I'd recommend looking into the documentation
   subdirectories on any Linux FTP site for the LDP (Linux Documentation
   Project) books.  This README is not meant to be documentation on the
   system: there are much better sources available.

 - There are various README files in the Documentation/ subdirectory:
   these typically contain kernel-specific installation notes for some 
   drivers for example. See Documentation/00-INDEX for a list of what
   is contained in each file.  Please read the Changes file, as it
   contains information about the problems, which may result by upgrading
   your kernel.

 - The Documentation/DocBook/ subdirectory contains several guides for
   kernel developers and users.  These guides can be rendered in a
   number of formats:  PostScript (.ps), PDF, HTML, & man-pages, among others.
   After installation, "make psdocs", "make pdfdocs", "make htmldocs",
   or "make mandocs" will render the documentation in the requested format.

INSTALLING the kernel source:

 - If you install the full sources, put the kernel tarball in a
   directory where you have permissions (eg. your home directory) and
   unpack it:

     gzip -cd linux-3.X.tar.gz | tar xvf -

   or

     bzip2 -dc linux-3.X.tar.bz2 | tar xvf -

   Replace "X" with the version number of the latest kernel.

   Do NOT use the /usr/src/linux area! This area has a (usually
   incomplete) set of kernel headers that are used by the library header
   files.  They should match the library, and not get messed up by
   whatever the kernel-du-jour happens to be.

 - You can also upgrade between 3.x releases by patching.  Patches are
   distributed in the traditional gzip and the newer bzip2 format.  To
   install by patching, get all the newer patch files, enter the
   top level directory of the kernel source (linux-3.X) and execute:

     gzip -cd ../patch-3.x.gz | patch -p1

   or

     bzip2 -dc ../patch-3.x.bz2 | patch -p1

   Replace "x" for all versions bigger than the version "X" of your current
   source tree, _in_order_, and you should be ok.  You may want to remove
   the backup files (some-file-name~ or some-file-name.orig), and make sure
   that there are no failed patches (some-file-name# or some-file-name.rej).
   If there are, either you or I have made a mistake.

   Unlike patches for the 3.x kernels, patches for the 3.x.y kernels
   (also known as the -stable kernels) are not incremental but instead apply
   directly to the base 3.x kernel.  For example, if your base kernel is 3.0
   and you want to apply the 3.0.3 patch, you must not first apply the 3.0.1
   and 3.0.2 patches. Similarly, if you are running kernel version 3.0.2 and
   want to jump to 3.0.3, you must first reverse the 3.0.2 patch (that is,
   patch -R) _before_ applying the 3.0.3 patch. You can read more on this in
   Documentation/applying-patches.txt

   Alternatively, the script patch-kernel can be used to automate this
   process.  It determines the current kernel version and applies any
   patches found.

     linux/scripts/patch-kernel linux

   The first argument in the command above is the location of the
   kernel source.  Patches are applied from the current directory, but
   an alternative directory can be specified as the second argument.

 - Make sure you have no stale .o files and dependencies lying around:

     cd linux
     make mrproper

   You should now have the sources correctly installed.

SOFTWARE REQUIREMENTS

   Compiling and running the 3.x kernels requires up-to-date
   versions of various software packages.  Consult
   Documentation/Changes for the minimum version numbers required
   and how to get updates for these packages.  Beware that using
   excessively old versions of these packages can cause indirect
   errors that are very difficult to track down, so don't assume that
   you can just update packages when obvious problems arise during
   build or operation.

BUILD directory for the kernel:

   When compiling the kernel, all output files will per default be
   stored together with the kernel source code.
   Using the option "make O=output/dir" allow you to specify an alternate
   place for the output files (including .config).
   Example:

     kernel source code: /usr/src/linux-3.X
     build directory:    /home/name/build/kernel

   To configure and build the kernel, use:

     cd /usr/src/linux-3.X
     make O=/home/name/build/kernel menuconfig
     make O=/home/name/build/kernel
     sudo make O=/home/name/build/kernel modules_install install

   Please note: If the 'O=output/dir' option is used, then it must be
   used for all invocations of make.

CONFIGURING the kernel:

   Do not skip this step even if you are only upgrading one minor
   version.  New configuration options are added in each release, and
   odd problems will turn up if the configuration files are not set up
   as expected.  If you want to carry your existing configuration to a
   new version with minimal work, use "make oldconfig", which will
   only ask you for the answers to new questions.

 - Alternative configuration commands are:

     "make config"      Plain text interface.

     "make menuconfig"  Text based color menus, radiolists & dialogs.

     "make nconfig"     Enhanced text based color menus.

     "make xconfig"     X windows (Qt) based configuration tool.

     "make gconfig"     X windows (Gtk) based configuration tool.

     "make oldconfig"   Default all questions based on the contents of
                        your existing ./.config file and asking about
                        new config symbols.

     "make silentoldconfig"
                        Like above, but avoids cluttering the screen
                        with questions already answered.
                        Additionally updates the dependencies.

     "make olddefconfig"
                        Like above, but sets new symbols to their default
                        values without prompting.

     "make defconfig"   Create a ./.config file by using the default
                        symbol values from either arch/$ARCH/defconfig
                        or arch/$ARCH/configs/${PLATFORM}_defconfig,
                        depending on the architecture.

     "make ${PLATFORM}_defconfig"
                        Create a ./.config file by using the default
                        symbol values from
                        arch/$ARCH/configs/${PLATFORM}_defconfig.
                        Use "make help" to get a list of all available
                        platforms of your architecture.

     "make allyesconfig"
                        Create a ./.config file by setting symbol
                        values to 'y' as much as possible.

     "make allmodconfig"
                        Create a ./.config file by setting symbol
                        values to 'm' as much as possible.

     "make allnoconfig" Create a ./.config file by setting symbol
                        values to 'n' as much as possible.

     "make randconfig"  Create a ./.config file by setting symbol
                        values to random values.

     "make localmodconfig" Create a config based on current config and
                           loaded modules (lsmod). Disables any module
                           option that is not needed for the loaded modules.

                           To create a localmodconfig for another machine,
                           store the lsmod of that machine into a file
                           and pass it in as a LSMOD parameter.

                   target$ lsmod > /tmp/mylsmod
                   target$ scp /tmp/mylsmod host:/tmp

                   host$ make LSMOD=/tmp/mylsmod localmodconfig

                           The above also works when cross compiling.

     "make localyesconfig" Similar to localmodconfig, except it will convert
                           all module options to built in (=y) options.

   You can find more information on using the Linux kernel config tools
   in Documentation/kbuild/kconfig.txt.

 - NOTES on "make config":

    - Having unnecessary drivers will make the kernel bigger, and can
      under some circumstances lead to problems: probing for a
      nonexistent controller card may confuse your other controllers

    - Compiling the kernel with "Processor type" set higher than 386
      will result in a kernel that does NOT work on a 386.  The
      kernel will detect this on bootup, and give up.

    - A kernel with math-emulation compiled in will still use the
      coprocessor if one is present: the math emulation will just
      never get used in that case.  The kernel will be slightly larger,
      but will work on different machines regardless of whether they
      have a math coprocessor or not.

    - The "kernel hacking" configuration details usually result in a
      bigger or slower kernel (or both), and can even make the kernel
      less stable by configuring some routines to actively try to
      break bad code to find kernel problems (kmalloc()).  Thus you
      should probably answer 'n' to the questions for "development",
      "experimental", or "debugging" features.

COMPILING the kernel:

 - Make sure you have at least gcc 3.2 available.
   For more information, refer to Documentation/Changes.

   Please note that you can still run a.out user programs with this kernel.

 - Do a "make" to create a compressed kernel image. It is also
   possible to do "make install" if you have lilo installed to suit the
   kernel makefiles, but you may want to check your particular lilo setup first.

   To do the actual install, you have to be root, but none of the normal
   build should require that. Don't take the name of root in vain.

 - If you configured any of the parts of the kernel as `modules', you
   will also have to do "make modules_install".

 - Verbose kernel compile/build output:

   Normally, the kernel build system runs in a fairly quiet mode (but not
   totally silent).  However, sometimes you or other kernel developers need
   to see compile, link, or other commands exactly as they are executed.
   For this, use "verbose" build mode.  This is done by inserting
   "V=1" in the "make" command.  E.g.:

     make V=1 all

   To have the build system also tell the reason for the rebuild of each
   target, use "V=2".  The default is "V=0".

 - Keep a backup kernel handy in case something goes wrong.  This is 
   especially true for the development releases, since each new release
   contains new code which has not been debugged.  Make sure you keep a
   backup of the modules corresponding to that kernel, as well.  If you
   are installing a new kernel with the same version number as your
   working kernel, make a backup of your modules directory before you
   do a "make modules_install".

   Alternatively, before compiling, use the kernel config option
   "LOCALVERSION" to append a unique suffix to the regular kernel version.
   LOCALVERSION can be set in the "General Setup" menu.

 - In order to boot your new kernel, you'll need to copy the kernel
   image (e.g. .../linux/arch/i386/boot/bzImage after compilation)
   to the place where your regular bootable kernel is found. 

 - Booting a kernel directly from a floppy without the assistance of a
   bootloader such as LILO, is no longer supported.

   If you boot Linux from the hard drive, chances are you use LILO, which
   uses the kernel image as specified in the file /etc/lilo.conf.  The
   kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or
   /boot/bzImage.  To use the new kernel, save a copy of the old image
   and copy the new image over the old one.  Then, you MUST RERUN LILO
   to update the loading map!! If you don't, you won't be able to boot
   the new kernel image.

   Reinstalling LILO is usually a matter of running /sbin/lilo. 
   You may wish to edit /etc/lilo.conf to specify an entry for your
   old kernel image (say, /vmlinux.old) in case the new one does not
   work.  See the LILO docs for more information. 

   After reinstalling LILO, you should be all set.  Shutdown the system,
   reboot, and enjoy!

   If you ever need to change the default root device, video mode,
   ramdisk size, etc.  in the kernel image, use the 'rdev' program (or
   alternatively the LILO boot options when appropriate).  No need to
   recompile the kernel to change these parameters. 

 - Reboot with the new kernel and enjoy. 

IF SOMETHING GOES WRONG:

 - If you have problems that seem to be due to kernel bugs, please check
   the file MAINTAINERS to see if there is a particular person associated
   with the part of the kernel that you are having trouble with. If there
   isn't anyone listed there, then the second best thing is to mail
   them to me (torvalds@linux-foundation.org), and possibly to any other
   relevant mailing-list or to the newsgroup.

 - In all bug-reports, *please* tell what kernel you are talking about,
   how to duplicate the problem, and what your setup is (use your common
   sense).  If the problem is new, tell me so, and if the problem is
   old, please try to tell me when you first noticed it.

 - If the bug results in a message like

     unable to handle kernel paging request at address C0000010
     Oops: 0002
     EIP:   0010:XXXXXXXX
     eax: xxxxxxxx   ebx: xxxxxxxx   ecx: xxxxxxxx   edx: xxxxxxxx
     esi: xxxxxxxx   edi: xxxxxxxx   ebp: xxxxxxxx
     ds: xxxx  es: xxxx  fs: xxxx  gs: xxxx
     Pid: xx, process nr: xx
     xx xx xx xx xx xx xx xx xx xx

   or similar kernel debugging information on your screen or in your
   system log, please duplicate it *exactly*.  The dump may look
   incomprehensible to you, but it does contain information that may
   help debugging the problem.  The text above the dump is also
   important: it tells something about why the kernel dumped code (in
   the above example, it's due to a bad kernel pointer). More information
   on making sense of the dump is in Documentation/oops-tracing.txt

 - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump
   as is, otherwise you will have to use the "ksymoops" program to make
   sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred).
   This utility can be downloaded from
   ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ .
   Alternatively, you can do the dump lookup by hand:

 - In debugging dumps like the above, it helps enormously if you can
   look up what the EIP value means.  The hex value as such doesn't help
   me or anybody else very much: it will depend on your particular
   kernel setup.  What you should do is take the hex value from the EIP
   line (ignore the "0010:"), and look it up in the kernel namelist to
   see which kernel function contains the offending address.

   To find out the kernel function name, you'll need to find the system
   binary associated with the kernel that exhibited the symptom.  This is
   the file 'linux/vmlinux'.  To extract the namelist and match it against
   the EIP from the kernel crash, do:

     nm vmlinux | sort | less

   This will give you a list of kernel addresses sorted in ascending
   order, from which it is simple to find the function that contains the
   offending address.  Note that the address given by the kernel
   debugging messages will not necessarily match exactly with the
   function addresses (in fact, that is very unlikely), so you can't
   just 'grep' the list: the list will, however, give you the starting
   point of each kernel function, so by looking for the function that
   has a starting address lower than the one you are searching for but
   is followed by a function with a higher address you will find the one
   you want.  In fact, it may be a good idea to include a bit of
   "context" in your problem report, giving a few lines around the
   interesting one. 

   If you for some reason cannot do the above (you have a pre-compiled
   kernel image or similar), telling me as much about your setup as
   possible will help.  Please read the REPORTING-BUGS document for details.

 - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you
   cannot change values or set break points.) To do this, first compile the
   kernel with -g; edit arch/i386/Makefile appropriately, then do a "make
   clean". You'll also need to enable CONFIG_PROC_FS (via "make config").

   After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore".
   You can now use all the usual gdb commands. The command to look up the
   point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes
   with the EIP value.)

   gdb'ing a non-running kernel currently fails because gdb (wrongly)
   disregards the starting offset for which the kernel is compiled.