[PATCH] Add reference_init.pl to `make buildcheck' target

`make buildcheck' only checks for calls to linker discarded sections,

reference_init checks for calls to sections discarded at run time, init was
cloned from discarded.  They are separate because the linker detects the
discarded case and I did not want to confuse users with messages about init
text/data while they were fixing the linker errors.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

scripts/reference_discarded.pl

@@ -106,4 +106,4 @@ foreach $object (keys(%object)) {
 }
 # printf("Done\n");
 
-exit($errorcount);
+exit(0);

scripts/reference_init.pl

+#!/usr/bin/perl -w
+#
+# reference_init.pl (C) Keith Owens 2002 <kaos@ocs.com.au>
+#
+# List references to vmlinux init sections from non-init sections.
+
+# Unfortunately I had to exclude references from read only data to .init
+# sections, almost all of these are false positives, they are created by
+# gcc.  The downside of excluding rodata is that there really are some
+# user references from rodata to init code, e.g. drivers/video/vgacon.c
+#
+# const struct consw vga_con = {
+#        con_startup:            vgacon_startup,
+#
+# where vgacon_startup is __init.  If you want to wade through the false
+# positives, take out the check for rodata.
+
+use strict;
+die($0 . " takes no arguments\n") if($#ARGV >= 0);
+
+my %object;
+my $object;
+my $line;
+my $ignore;
+
+$| = 1;
+
+printf("Finding objects, ");
+open(OBJDUMP_LIST, "find . -name '*.o' | xargs objdump -h |") || die "getting objdump list failed";
+while (defined($line = <OBJDUMP_LIST>)) {
+	chomp($line);
+	if ($line =~ /:\s+file format/) {
+		($object = $line) =~ s/:.*//;
+		$object{$object}->{'module'} = 0;
+		$object{$object}->{'size'} = 0;
+		$object{$object}->{'off'} = 0;
+	}
+	if ($line =~ /^\s*\d+\s+\.modinfo\s+/) {
+		$object{$object}->{'module'} = 1;
+	}
+	if ($line =~ /^\s*\d+\s+\.comment\s+/) {
+		($object{$object}->{'size'}, $object{$object}->{'off'}) = (split(' ', $line))[2,5];
+	}
+}
+close(OBJDUMP_LIST);
+printf("%d objects, ", scalar keys(%object));
+$ignore = 0;
+foreach $object (keys(%object)) {
+	if ($object{$object}->{'module'}) {
+		++$ignore;
+		delete($object{$object});
+	}
+}
+printf("ignoring %d module(s)\n", $ignore);
+
+# Ignore conglomerate objects, they have been built from multiple objects and we
+# only care about the individual objects.  If an object has more than one GCC:
+# string in the comment section then it is conglomerate.  This does not filter
+# out conglomerates that consist of exactly one object, can't be helped.
+
+printf("Finding conglomerates, ");
+$ignore = 0;
+foreach $object (keys(%object)) {
+	if (exists($object{$object}->{'off'})) {
+		my ($off, $size, $comment, $l);
+		$off = hex($object{$object}->{'off'});
+		$size = hex($object{$object}->{'size'});
+		open(OBJECT, "<$object") || die "cannot read $object";
+		seek(OBJECT, $off, 0) || die "seek to $off in $object failed";
+		$l = read(OBJECT, $comment, $size);
+		die "read $size bytes from $object .comment failed" if ($l != $size);
+		close(OBJECT);
+		if ($comment =~ /GCC\:.*GCC\:/m) {
+			++$ignore;
+			delete($object{$object});
+		}
+	}
+}
+printf("ignoring %d conglomerate(s)\n", $ignore);
+
+printf("Scanning objects\n");
+foreach $object (sort(keys(%object))) {
+	my $from;
+	open(OBJDUMP, "objdump -r $object|") || die "cannot objdump -r $object";
+	while (defined($line = <OBJDUMP>)) {
+		chomp($line);
+		if ($line =~ /RELOCATION RECORDS FOR /) {
+			($from = $line) =~ s/.*\[([^]]*).*/$1/;
+		}
+		if (($line =~ /\.init$/ || $line =~ /\.init\./) &&
+		    ($from !~ /\.init$/ &&
+		     $from !~ /\.init\./ &&
+		     $from !~ /\.stab$/ &&
+		     $from !~ /\.rodata$/ &&
+		     $from !~ /\.text\.lock$/ &&
+		     $from !~ /\.debug_/)) {
+			printf("Error: %s %s refers to %s\n", $object, $from, $line);
+		}
+	}
+	close(OBJDUMP);
+}
+printf("Done\n");