diff --git a/tools/tools/README b/tools/tools/README
index 4f3206f92f46..fb28a807d9dc 100644
--- a/tools/tools/README
+++ b/tools/tools/README
@@ -23,6 +23,8 @@ gdb_regofs	A simple tool that prints out a register offset table
 		for mapping gdb(1) register numbers to struct reg and
 		struct fpreg offsets. The tool is useful on selected
 		platforms only.
+genericize	Turn a kernel config into something that can more easily
+		be diffed against the appropriate GENERIC.
 hcomp		Compress header files by removing comments and whitespace.
 html-mv         Rename HTML generated filenames to human readable filenames.
 ifinfo		Uses the interface MIB to print out all the information
diff --git a/tools/tools/genericize/Makefile b/tools/tools/genericize/Makefile
new file mode 100644
index 000000000000..54b3fdb86134
--- /dev/null
+++ b/tools/tools/genericize/Makefile
@@ -0,0 +1,5 @@
+# $FreeBSD$
+
+SCRIPTS=	genericize.pl
+
+.include <bsd.prog.mk>
diff --git a/tools/tools/genericize/genericize.pl b/tools/tools/genericize/genericize.pl
new file mode 100755
index 000000000000..3cef7b1f6cd8
--- /dev/null
+++ b/tools/tools/genericize/genericize.pl
@@ -0,0 +1,108 @@
+#!/usr/bin/perl -w
+#-
+# Copyright (c) 2004 Dag-Erling Coïdan Smørgrav
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer
+#    in this position and unchanged.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# $FreeBSD$
+#
+
+use strict;
+
+MAIN:{
+    my %config;
+    my $machine;
+    my $ident;
+
+    while (<>) {
+	chomp();
+	s/\s*(\#.*)?$//;
+	next unless $_;
+	#print("$_\n");
+	my ($keyword, $values) = split(' ', $_, 2);
+	foreach my $value (split(/,\s*/, $values)) {
+	    if ($keyword eq 'machine') {
+		$machine = $value;
+	    } elsif ($keyword eq 'ident') {
+		$ident = $value;
+	    } else {
+		$config{$keyword}->{$value} = 1;
+	    }
+	    #print "$keyword $value\n";
+	}
+    }
+
+    my $generic = "/usr/src/sys/$machine/conf/GENERIC";
+    local *GENERIC;
+    open(GENERIC, "<", $generic)
+	or die("$generic: $!\n");
+    my $blank = 0;
+    while (<GENERIC>) {
+	my $line = $_;
+	chomp();
+	++$blank unless $_;
+	s/\s*(\#.*)?$//;
+	next unless $_;
+	my ($keyword, $value) = split(' ', $_);
+	if ($keyword eq 'machine') {
+	    die("$generic is for $value, not $machine\n")
+		unless ($value eq $machine);
+	    if ($blank) {
+		print "\n";
+		$blank = 0;
+	    }
+	} elsif ($keyword eq 'ident') {
+	    $line =~ s/$value/$ident/;
+	} elsif ($config{$keyword}->{$value}) {
+	    delete($config{$keyword}->{$value});
+	    delete($config{$keyword})
+		unless %{$config{$keyword}};
+	} else {
+	    next;
+	}
+	if ($blank) {
+	    print "\n";
+	    $blank = 0;
+	}
+	print $line;
+    }
+    close(GENERIC);
+
+    if (%config) {
+	print "\n# Addenda\n";
+	foreach my $keyword (sort(keys(%config))) {
+	    foreach my $value (sort(keys(%{$config{$keyword}}))) {
+		print "$keyword";
+		if (length($keyword) < 7) {
+		    print "\t";
+		} elsif (length($keyword) == 7) {
+		    print " ";
+		}
+		print "\t$value\n";
+	    }
+	}
+    }
+    exit(0);
+}