744b947ef8
This change will let us to have full configuration of a running kernel available in sysctl: sysctl -b kern.conftxt The same configuration is also contained within the kernel image. It can be obtained with: config -x <kernelfile> Current functionality lets you to quickly recover kernel configuration, by simply redirecting output from commands presented above and starting kernel build procedure. "include" statements are also honored, which means options and devices from included files are also included. Please note that comments from configuration files are not preserved by default. In order to preserve them, you can use -C flag for config(8). This will bring configuration file and included files literally; however, redirection to a file no longer works directly. This commit was followed by discussion, that took place on freebsd-current@. For more details, look here: http://lists.freebsd.org/pipermail/freebsd-current/2007-March/069994.html http://lists.freebsd.org/pipermail/freebsd-current/2007-May/071844.html Development of this patch took place in Perforce, hierarchy: //depot/user/wkoszek/wkoszek_kconftxt/ Support from: freebsd-current@ (links above) Reviewed by: imp@ Approved by: imp@
275 lines
7.2 KiB
Groff
275 lines
7.2 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)config.8 8.2 (Berkeley) 4/19/94
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.\" $FreeBSD$
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.\"
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.Dd May 8, 2007
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.Dt CONFIG 8
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.Os
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.Sh NAME
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.Nm config
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.Nd build system configuration files
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.Sh SYNOPSIS
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.Nm
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.Op Fl CVgp
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.Op Fl d Ar destdir
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.Ar SYSTEM_NAME
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.Nm
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.Op Fl x Ar kernel
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.Sh DESCRIPTION
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.\" This is the old version of the
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.\" .Nm
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.\" utility.
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.\" It understands the old autoconfiguration scheme
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.\" used on the HP300, i386, DECstation, and derivative platforms.
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.\" The new version of
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.\" .Nm
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.\" is used with the
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.\" SPARC platform.
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.\" Only the version of
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.\" .Nm
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.\" applicable to the architecture that you are running
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.\" will be installed on your machine.
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.\" .Pp
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The
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.Nm
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utility builds a set of system configuration files from the file
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.Ar SYSTEM_NAME
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which describes
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the system to configure.
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A second file
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tells
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.Nm
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what files are needed to generate a system and
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can be augmented by configuration specific set of files
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that give alternate files for a specific machine
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(see the
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.Sx FILES
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section below).
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.Pp
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Available options and operands:
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.Bl -tag -width ".Ar SYSTEM_NAME"
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.It Fl V
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Print the
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.Nm
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version number.
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.It Fl C
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If the INCLUDE_CONFIG_FILE is present in a configuration file,
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kernel image will contain full configuration files included
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literally (preserving comments).
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This flag is kept for backward compatibility.
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.It Fl d Ar destdir
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Use
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.Ar destdir
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as the output directory, instead of the default one.
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Note that
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.Nm
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does not append
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.Ar SYSTEM_NAME
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to the directory given.
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.It Fl g
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Configure a system for debugging.
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.It Fl x Ar kernel
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Print kernel configuration file embedded into a kernel
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file.
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This option makes sense only if
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.Cd "options INCLUDE_CONFIG_FILE"
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entry was present in your configuration file.
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.It Fl p
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Configure a system for profiling; for example,
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.Xr kgmon 8
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and
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.Xr gprof 1 .
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If two or more
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.Fl p
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options are supplied,
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.Nm
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configures a system for high resolution profiling.
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.It Ar SYSTEM_NAME
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Specify the name of the system configuration file
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containing device specifications, configuration options
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and other system parameters for one system configuration.
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.El
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.Pp
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The
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.Nm
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utility should be run from the
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.Pa conf
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subdirectory of the system source (usually
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.Pa /sys/ Ns Va ARCH Ns Pa /conf ) ,
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where
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.Va ARCH
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represents one of the architectures supported by
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.Fx .
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The
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.Nm
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utility creates the directory
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.Pa ../compile/ Ns Ar SYSTEM_NAME
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or the one given with the
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.Fl d
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option
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as necessary and places all output files there.
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The output of
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.Nm
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consists of a number of files; for the
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.Tn i386 ,
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they are:
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.Pa Makefile ,
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used by
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.Xr make 1
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in building the system;
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header files,
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definitions of
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the number of various devices that will be compiled into the system.
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.Pp
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After running
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.Nm ,
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it is necessary to run
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.Dq Li make depend
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in the directory where the new makefile
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was created.
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The
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.Nm
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utility prints a reminder of this when it completes.
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.Pp
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If any other error messages are produced by
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.Nm ,
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the problems in the configuration file should be corrected and
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.Nm
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should be run again.
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Attempts to compile a system that had configuration errors
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are likely to fail.
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.Sh DEBUG KERNELS
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Traditional
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.Bx
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kernels are compiled without symbols due to the heavy load on the
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system when compiling a
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.Dq debug
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kernel.
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A debug kernel contains complete symbols for all the source files, and
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enables an experienced kernel programmer to analyse the cause of a problem.
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The
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debuggers available prior to
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.Bx 4.4 Lite
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were able to find some information
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from a normal kernel;
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.Xr gdb 1
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provides very little support for normal kernels, and a debug kernel is needed
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for any meaningful analysis.
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.Pp
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For reasons of history, time and space, building a debug kernel is not the
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default with
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.Fx :
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a debug kernel takes up to 30% longer to build and
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requires about 30 MB of disk storage in the build directory, compared to about 6
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MB for a non-debug kernel.
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A debug kernel is about 11 MB in size, compared to
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about 2 MB for a non-debug kernel.
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This space is used both in the root file
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system and at run time in memory.
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Use the
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.Fl g
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option to build a debug kernel.
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With this option,
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.Nm
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causes two kernel files to be built in the kernel build directory:
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.Bl -bullet
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.It
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.Pa kernel.debug
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is the complete debug kernel.
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.It
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.Pa kernel
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is a copy of the kernel with the debug symbols stripped off.
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This is equivalent
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to the normal non-debug kernel.
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.El
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.Pp
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There is currently little sense in installing and booting from a debug kernel,
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since the only tools available which use the symbols do not run on-line.
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There
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are therefore two options for installing a debug kernel:
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.Bl -bullet
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.It
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.Dq Li "make install"
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installs
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.Pa kernel
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in the root file system.
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.It
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.Dq Li "make install.debug"
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installs
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.Pa kernel.debug
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in the root file system.
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.El
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.Sh FILES
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.Bl -tag -width ".Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME" -compact
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.It Pa /sys/conf/files
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list of common files system is built from
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.It Pa /sys/conf/Makefile. Ns Va ARCH
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generic makefile for the
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.Va ARCH
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.It Pa /sys/conf/files. Ns Va ARCH
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list of
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.Va ARCH
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specific files
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.It Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME
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default kernel build directory for system
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.Ar SYSTEM_NAME
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on
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.Va ARCH .
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.El
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.Sh SEE ALSO
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.Xr config 5
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.Pp
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The
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.Sx SYNOPSIS
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portion of each device in section 4.
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.Rs
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.%T "Building 4.3 BSD UNIX System with Config"
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.Re
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.Sh HISTORY
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The
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.Nm
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utility appeared in
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.Bx 4.1 .
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.Pp
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Before support for
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.Fl x
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was introduced,
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.Cd "options INCLUDE_CONFIG_FILE"
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included entire configuration file that used to be embedded in
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the new kernel.
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This meant that
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.Xr strings 1
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could be used to extract it from a kernel:
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to extract the configuration information, you had to use
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the command:
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.Pp
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.Dl "strings -n 3 kernel | sed -n 's/^___//p'"
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.Sh BUGS
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The line numbers reported in error messages are usually off by one.
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