scripts/namespace.pl - third_party/linux - Git at Google


            
            #!/usr/bin/env perl

            
            #

            
            #	namespace.pl.  Mon Aug 30 2004

            
            #

            
            #	Perform a name space analysis on the linux kernel.

            
            #

            
            #	Copyright Keith Owens <kaos@ocs.com.au>.  GPL.

            
            #

            
            #	Invoke by changing directory to the top of the kernel object

            
            #	tree then namespace.pl, no parameters.

            
            #

            
            #	Tuned for 2.1.x kernels with the new module handling, it will

            
            #	work with 2.0 kernels as well.

            
            #

            
            #	Last change 2.6.9-rc1, adding support for separate source and object

            
            #	trees.

            
            #

            
            #	The source must be compiled/assembled first, the object files

            
            #	are the primary input to this script.  Incomplete or missing

            
            #	objects will result in a flawed analysis.  Compile both vmlinux

            
            #	and modules.

            
            #

            
            #	Even with complete objects, treat the result of the analysis

            
            #	with caution.  Some external references are only used by

            
            #	certain architectures, others with certain combinations of

            
            #	configuration parameters.  Ideally the source should include

            
            #	something like

            
            #

            
            #	#ifndef CONFIG_...

            
            #	static

            
            #	#endif

            
            #	symbol_definition;

            
            #

            
            #	so the symbols are defined as static unless a particular

            
            #	CONFIG_... requires it to be external.

            
            #

            
            #	A symbol that is suffixed with '(export only)' has these properties

            
            #

            
            #	* It is global.

            
            #	* It is marked EXPORT_SYMBOL or EXPORT_SYMBOL_GPL, either in the same

            
            #	  source file or a different source file.

            
            #	* Given the current .config, nothing uses the symbol.

            
            #

            
            #	The symbol is a candidate for conversion to static, plus removal of the

            
            #	export.  But be careful that a different .config might use the symbol.

            
            #

            
            #

            
            #	Name space analysis and cleanup is an iterative process.  You cannot

            
            #	expect to find all the problems in a single pass.

            
            #

            
            #	* Identify possibly unnecessary global declarations, verify that they

            
            #	  really are unnecessary and change them to static.

            
            #	* Compile and fix up gcc warnings about static, removing dead symbols

            
            #	  as necessary.

            
            #	* make clean and rebuild with different configs (especially

            
            #	  CONFIG_MODULES=n) to see which symbols are being defined when the

            
            #	  config does not require them.  These symbols bloat the kernel object

            
            #	  for no good reason, which is frustrating for embedded systems.

            
            #	* Wrap config sensitive symbols in #ifdef CONFIG_foo, as long as the

            
            #	  code does not get too ugly.

            
            #	* Repeat the name space analysis until you can live with with the

            
            #	  result.

            
            #


            use warnings;

            
            use strict;

            
            use File::Find;


            my $nm = ($ENV{'NM'} || "nm") . " -p";

            
            my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment";

            
            my $srctree = "";

            
            my $objtree = "";

            
            $srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));

            
            $objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));


            if ($#ARGV != -1) {

            
            	print STDERR "usage: $0 takes no parameters\n";

            
            	die("giving up\n");

            
            }


            my %nmdata = ();	# nm data for each object

            
            my %def = ();		# all definitions for each name

            
            my %ksymtab = ();	# names that appear in __ksymtab_

            
            my %ref = ();		# $ref{$name} exists if there is a true external reference to $name

            
            my %export = ();	# $export{$name} exists if there is an EXPORT_... of $name


            my %nmexception = (

            
                'fs/ext3/bitmap'			=> 1,

            
                'fs/ext4/bitmap'			=> 1,

            
                'arch/x86/lib/thunk_32'		=> 1,

            
                'arch/x86/lib/cmpxchg'		=> 1,

            
                'arch/x86/vdso/vdso32/note'		=> 1,

            
                'lib/irq_regs'			=> 1,

            
                'usr/initramfs_data'		=> 1,

            
                'drivers/scsi/aic94xx/aic94xx_dump'	=> 1,

            
                'drivers/scsi/libsas/sas_dump'	=> 1,

            
                'lib/dec_and_lock'			=> 1,

            
                'drivers/ide/ide-probe-mini'	=> 1,

            
                'usr/initramfs_data'		=> 1,

            
                'drivers/acpi/acpia/exdump'		=> 1,

            
                'drivers/acpi/acpia/rsdump'		=> 1,

            
                'drivers/acpi/acpia/nsdumpdv'	=> 1,

            
                'drivers/acpi/acpia/nsdump'		=> 1,

            
                'arch/ia64/sn/kernel/sn2/io'	=> 1,

            
                'arch/ia64/kernel/gate-data'	=> 1,

            
                'security/capability'		=> 1,

            
                'fs/ntfs/sysctl'			=> 1,

            
                'fs/jfs/jfs_debug'			=> 1,

            
            );


            my %nameexception = (

            
                'mod_use_count_'	 => 1,

            
                '__initramfs_end'	=> 1,

            
                '__initramfs_start'	=> 1,

            
                '_einittext'	=> 1,

            
                '_sinittext'	=> 1,

            
                'kallsyms_names'	=> 1,

            
                'kallsyms_num_syms'	=> 1,

            
                'kallsyms_addresses'=> 1,

            
                'kallsyms_offsets'	=> 1,

            
                'kallsyms_relative_base'=> 1,

            
                '__this_module'	=> 1,

            
                '_etext'		=> 1,

            
                '_edata'		=> 1,

            
                '_end'		=> 1,

            
                '__bss_start'	=> 1,

            
                '_text'		=> 1,

            
                '_stext'		=> 1,

            
                '__gp'		=> 1,

            
                'ia64_unw_start'	=> 1,

            
                'ia64_unw_end'	=> 1,

            
                '__init_begin'	=> 1,

            
                '__init_end'	=> 1,

            
                '__bss_stop'	=> 1,

            
                '__nosave_begin'	=> 1,

            
                '__nosave_end'	=> 1,

            
                'pg0'		=> 1,

            
                'vdso_enabled'	=> 1,

            
                '__stack_chk_fail'  => 1,

            
                'VDSO32_PRELINK'	=> 1,

            
                'VDSO32_vsyscall'	=> 1,

            
                'VDSO32_rt_sigreturn'=>1,

            
                'VDSO32_sigreturn'	=> 1,

            
            );


            &find(\&linux_objects, '.');	# find the objects and do_nm on them

            
            &list_multiply_defined();

            
            &resolve_external_references();

            
            &list_extra_externals();


            exit(0);


            sub linux_objects

            
            {

            
            	# Select objects, ignoring objects which are only created by

            
            	# merging other objects.  Also ignore all of modules, scripts

            
            	# and compressed.  Most conglomerate objects are handled by do_nm,

            
            	# this list only contains the special cases.  These include objects

            
            	# that are linked from just one other object and objects for which

            
            	# there is really no permanent source file.

            
            	my $basename = $_;

            
            	$_ = $File::Find::name;

            
            	s:^\./::;

            
            	if (/.*\.o$/ &&

            
            		! (

            
            		m:/built-in.o$:

            
            		|| m:arch/x86/vdso/:

            
            		|| m:arch/x86/boot/:

            
            		|| m:arch/ia64/ia32/ia32.o$:

            
            		|| m:arch/ia64/kernel/gate-syms.o$:

            
            		|| m:arch/ia64/lib/__divdi3.o$:

            
            		|| m:arch/ia64/lib/__divsi3.o$:

            
            		|| m:arch/ia64/lib/__moddi3.o$:

            
            		|| m:arch/ia64/lib/__modsi3.o$:

            
            		|| m:arch/ia64/lib/__udivdi3.o$:

            
            		|| m:arch/ia64/lib/__udivsi3.o$:

            
            		|| m:arch/ia64/lib/__umoddi3.o$:

            
            		|| m:arch/ia64/lib/__umodsi3.o$:

            
            		|| m:arch/ia64/scripts/check_gas_for_hint.o$:

            
            		|| m:arch/ia64/sn/kernel/xp.o$:

            
            		|| m:boot/bbootsect.o$:

            
            		|| m:boot/bsetup.o$:

            
            		|| m:/bootsect.o$:

            
            		|| m:/boot/setup.o$:

            
            		|| m:/compressed/:

            
            		|| m:drivers/cdrom/driver.o$:

            
            		|| m:drivers/char/drm/tdfx_drv.o$:

            
            		|| m:drivers/ide/ide-detect.o$:

            
            		|| m:drivers/ide/pci/idedriver-pci.o$:

            
            		|| m:drivers/media/media.o$:

            
            		|| m:drivers/scsi/sd_mod.o$:

            
            		|| m:drivers/video/video.o$:

            
            		|| m:fs/devpts/devpts.o$:

            
            		|| m:fs/exportfs/exportfs.o$:

            
            		|| m:fs/hugetlbfs/hugetlbfs.o$:

            
            		|| m:fs/msdos/msdos.o$:

            
            		|| m:fs/nls/nls.o$:

            
            		|| m:fs/ramfs/ramfs.o$:

            
            		|| m:fs/romfs/romfs.o$:

            
            		|| m:fs/vfat/vfat.o$:

            
            		|| m:init/mounts.o$:

            
            		|| m:^modules/:

            
            		|| m:net/netlink/netlink.o$:

            
            		|| m:net/sched/sched.o$:

            
            		|| m:/piggy.o$:

            
            		|| m:^scripts/:

            
            		|| m:sound/.*/snd-:

            
            		|| m:^.*/\.tmp_:

            
            		|| m:^\.tmp_:

            
            		|| m:/vmlinux-obj.o$:

            
            		|| m:^tools/:

            
            		)

            
            	) {

            
            		do_nm($basename, $_);

            
            	}

            
            	$_ = $basename;		# File::Find expects $_ untouched (undocumented)

            
            }


            sub do_nm

            
            {

            
            	my ($basename, $fullname) = @_;

            
            	my ($source, $type, $name);

            
            	if (! -e $basename) {

            
            		printf STDERR "$basename does not exist\n";

            
            		return;

            
            	}

            
            	if ($fullname !~ /\.o$/) {

            
            		printf STDERR "$fullname is not an object file\n";

            
            		return;

            
            	}

            
            	($source = $basename) =~ s/\.o$//;

            
            	if (-e "$source.c" || -e "$source.S") {

            
            		$source = "$objtree$File::Find::dir/$source";

            
            	} else {

            
            		$source = "$srctree$File::Find::dir/$source";

            
            	}

            
            	if (! -e "$source.c" && ! -e "$source.S") {

            
            		# No obvious source, exclude the object if it is conglomerate

            
            	        open(my $objdumpdata, "$objdump $basename|")

            
            		    or die "$objdump $fullname failed $!\n";


            		my $comment;

            
            		while (<$objdumpdata>) {

            
            			chomp();

            
            			if (/^In archive/) {

            
            				# Archives are always conglomerate

            
            				$comment = "GCC:GCC:";

            
            				last;

            
            			}

            
            			next if (! /^[ 0-9a-f]{5,} /);

            
            			$comment .= substr($_, 43);

            
            		}

            
            		close($objdumpdata);


            		if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) {

            
            			printf STDERR "No source file found for $fullname\n";

            
            		}

            
            		return;

            
            	}

            
            	open (my $nmdata, "$nm $basename|")

            
            	    or die "$nm $fullname failed $!\n";


            	my @nmdata;

            
            	while (<$nmdata>) {

            
            		chop;

            
            		($type, $name) = (split(/ +/, $_, 3))[1..2];

            
            		# Expected types

            
            		# A absolute symbol

            
            		# B weak external reference to data that has been resolved

            
            		# C global variable, uninitialised

            
            		# D global variable, initialised

            
            		# G global variable, initialised, small data section

            
            		# R global array, initialised

            
            		# S global variable, uninitialised, small bss

            
            		# T global label/procedure

            
            		# U external reference

            
            		# W weak external reference to text that has been resolved

            
            		# V similar to W, but the value of the weak symbol becomes zero with no error.

            
            		# a assembler equate

            
            		# b static variable, uninitialised

            
            		# d static variable, initialised

            
            		# g static variable, initialised, small data section

            
            		# r static array, initialised

            
            		# s static variable, uninitialised, small bss

            
            		# t static label/procedures

            
            		# w weak external reference to text that has not been resolved

            
            		# v similar to w

            
            		# ? undefined type, used a lot by modules

            
            		if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) {

            
            			printf STDERR "nm output for $fullname contains unknown type '$_'\n";

            
            		}

            
            		elsif ($name =~ /\./) {

            
            			# name with '.' is local static

            
            		}

            
            		else {

            
            			$type = 'R' if ($type eq '?');	# binutils replaced ? with R at one point

            
            			# binutils keeps changing the type for exported symbols, force it to R

            
            			$type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/);

            
            			$name =~ s/_R[a-f0-9]{8}$//;	# module versions adds this

            
            			if ($type =~ /[ABCDGRSTWV]/ &&

            
            				$name ne 'init_module' &&

            
            				$name ne 'cleanup_module' &&

            
            				$name ne 'Using_Versions' &&

            
            				$name !~ /^Version_[0-9]+$/ &&

            
            				$name !~ /^__parm_/ &&

            
            				$name !~ /^__kstrtab/ &&

            
            				$name !~ /^__ksymtab/ &&

            
            				$name !~ /^__kcrctab_/ &&

            
            				$name !~ /^__exitcall_/ &&

            
            				$name !~ /^__initcall_/ &&

            
            				$name !~ /^__kdb_initcall_/ &&

            
            				$name !~ /^__kdb_exitcall_/ &&

            
            				$name !~ /^__module_/ &&

            
            				$name !~ /^__mod_/ &&

            
            				$name !~ /^__crc_/ &&

            
            				$name ne '__this_module' &&

            
            				$name ne 'kernel_version') {

            
            				if (!exists($def{$name})) {

            
            					$def{$name} = [];

            
            				}

            
            				push(@{$def{$name}}, $fullname);

            
            			}

            
            			push(@nmdata, "$type $name");

            
            			if ($name =~ /^__ksymtab_/) {

            
            				$name = substr($name, 10);

            
            				if (!exists($ksymtab{$name})) {

            
            					$ksymtab{$name} = [];

            
            				}

            
            				push(@{$ksymtab{$name}}, $fullname);

            
            			}

            
            		}

            
            	}

            
            	close($nmdata);


            	if ($#nmdata < 0) {

            
            	    printf "No nm data for $fullname\n"

            
            		unless $nmexception{$fullname};

            
            	    return;

            
            	}

            
            	$nmdata{$fullname} = \@nmdata;

            
            }


            sub drop_def

            
            {

            
            	my ($object, $name) = @_;

            
            	my $nmdata = $nmdata{$object};

            
            	my ($i, $j);

            
            	for ($i = 0; $i <= $#{$nmdata}; ++$i) {

            
            		if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {

            
            			splice(@{$nmdata{$object}}, $i, 1);

            
            			my $def = $def{$name};

            
            			for ($j = 0; $j < $#{$def{$name}}; ++$j) {

            
            				if ($def{$name}[$j] eq $object) {

            
            					splice(@{$def{$name}}, $j, 1);

            
            				}

            
            			}

            
            			last;

            
            		}

            
            	}

            
            }


            sub list_multiply_defined

            
            {

            
            	foreach my $name (keys(%def)) {

            
            		if ($#{$def{$name}} > 0) {

            
            			# Special case for cond_syscall

            
            			if ($#{$def{$name}} == 1 &&

            
            			   ($name =~ /^sys_/ || $name =~ /^compat_sys_/ ||

            
            			    $name =~ /^sys32_/)) {

            
            				if($def{$name}[0] eq "kernel/sys_ni.o" ||

            
            				   $def{$name}[1] eq "kernel/sys_ni.o") {

            
            					&drop_def("kernel/sys_ni.o", $name);

            
            					next;

            
            				}

            
            			}


            			printf "$name is multiply defined in :-\n";

            
            			foreach my $module (@{$def{$name}}) {

            
            				printf "\t$module\n";

            
            			}

            
            		}

            
            	}

            
            }


            sub resolve_external_references

            
            {

            
            	my ($kstrtab, $ksymtab, $export);


            	printf "\n";

            
            	foreach my $object (keys(%nmdata)) {

            
            		my $nmdata = $nmdata{$object};

            
            		for (my $i = 0; $i <= $#{$nmdata}; ++$i) {

            
            			my ($type, $name) = split(' ', $nmdata->[$i], 2);

            
            			if ($type eq "U" || $type eq "w") {

            
            				if (exists($def{$name}) || exists($ksymtab{$name})) {

            
            					# add the owning object to the nmdata

            
            					$nmdata->[$i] = "$type $name $object";

            
            					# only count as a reference if it is not EXPORT_...

            
            					$kstrtab = "R __kstrtab_$name";

            
            					$ksymtab = "R __ksymtab_$name";

            
            					$export = 0;

            
            					for (my $j = 0; $j <= $#{$nmdata}; ++$j) {

            
            						if ($nmdata->[$j] eq $kstrtab ||

            
            						    $nmdata->[$j] eq $ksymtab) {

            
            							$export = 1;

            
            							last;

            
            						}

            
            					}

            
            					if ($export) {

            
            						$export{$name} = "";

            
            					}

            
            					else {

            
            						$ref{$name} = ""

            
            					}

            
            				}

            
            				elsif ( ! $nameexception{$name}

            
            					&& $name !~ /^__sched_text_/

            
            					&& $name !~ /^__start_/

            
            					&& $name !~ /^__end_/

            
            					&& $name !~ /^__stop_/

            
            					&& $name !~ /^__scheduling_functions_.*_here/

            
            					&& $name !~ /^__.*initcall_/

            
            					&& $name !~ /^__.*per_cpu_start/

            
            					&& $name !~ /^__.*per_cpu_end/

            
            					&& $name !~ /^__alt_instructions/

            
            					&& $name !~ /^__setup_/

            
            					&& $name !~ /^__mod_timer/

            
            					&& $name !~ /^__mod_page_state/

            
            					&& $name !~ /^init_module/

            
            					&& $name !~ /^cleanup_module/

            
            				) {

            
            					printf "Cannot resolve ";

            
            					printf "weak " if ($type eq "w");

            
            					printf "reference to $name from $object\n";

            
            				}

            
            			}

            
            		}

            
            	}

            
            }


            sub list_extra_externals

            
            {

            
            	my %noref = ();


            	foreach my $name (keys(%def)) {

            
            		if (! exists($ref{$name})) {

            
            			my @module = @{$def{$name}};

            
            			foreach my $module (@module) {

            
            				if (! exists($noref{$module})) {

            
            					$noref{$module} = [];

            
            				}

            
            				push(@{$noref{$module}}, $name);

            
            			}

            
            		}

            
            	}

            
            	if (%noref) {

            
            		printf "\nExternally defined symbols with no external references\n";

            
            		foreach my $module (sort(keys(%noref))) {

            
            			printf "  $module\n";

            
            			foreach (sort(@{$noref{$module}})) {

            
            			    my $export;

            
            			    if (exists($export{$_})) {

            
            				$export = " (export only)";

            
            			    } else {

            
            				$export = "";

            
            			    }

            
            			    printf "    $_$export\n";

            
            			}

            
            		}

            
            	}

            
            }
	#!/usr/bin/env perl
	#
	# namespace.pl. Mon Aug 30 2004
	#
	# Perform a name space analysis on the linux kernel.
	#
	# Copyright Keith Owens <kaos@ocs.com.au>. GPL.
	#
	# Invoke by changing directory to the top of the kernel object
	# tree then namespace.pl, no parameters.
	#
	# Tuned for 2.1.x kernels with the new module handling, it will
	# work with 2.0 kernels as well.
	#
	# Last change 2.6.9-rc1, adding support for separate source and object
	# trees.
	#
	# The source must be compiled/assembled first, the object files
	# are the primary input to this script. Incomplete or missing
	# objects will result in a flawed analysis. Compile both vmlinux
	# and modules.
	#
	# Even with complete objects, treat the result of the analysis
	# with caution. Some external references are only used by
	# certain architectures, others with certain combinations of
	# configuration parameters. Ideally the source should include
	# something like
	#
	# #ifndef CONFIG_...
	# static
	# #endif
	# symbol_definition;
	#
	# so the symbols are defined as static unless a particular
	# CONFIG_... requires it to be external.
	#
	# A symbol that is suffixed with '(export only)' has these properties
	#
	# * It is global.
	# * It is marked EXPORT_SYMBOL or EXPORT_SYMBOL_GPL, either in the same
	# source file or a different source file.
	# * Given the current .config, nothing uses the symbol.
	#
	# The symbol is a candidate for conversion to static, plus removal of the
	# export. But be careful that a different .config might use the symbol.
	#
	#
	# Name space analysis and cleanup is an iterative process. You cannot
	# expect to find all the problems in a single pass.
	#
	# * Identify possibly unnecessary global declarations, verify that they
	# really are unnecessary and change them to static.
	# * Compile and fix up gcc warnings about static, removing dead symbols
	# as necessary.
	# * make clean and rebuild with different configs (especially
	# CONFIG_MODULES=n) to see which symbols are being defined when the
	# config does not require them. These symbols bloat the kernel object
	# for no good reason, which is frustrating for embedded systems.
	# * Wrap config sensitive symbols in #ifdef CONFIG_foo, as long as the
	# code does not get too ugly.
	# * Repeat the name space analysis until you can live with with the
	# result.
	#

	use warnings;
	use strict;
	use File::Find;

	my $nm = ($ENV{'NM'} \|\| "nm") . " -p";
	my $objdump = ($ENV{'OBJDUMP'} \|\| "objdump") . " -s -j .comment";
	my $srctree = "";
	my $objtree = "";
	$srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
	$objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));

	if ($#ARGV != -1) {
	print STDERR "usage: $0 takes no parameters\n";
	die("giving up\n");
	}

	my %nmdata = (); # nm data for each object
	my %def = (); # all definitions for each name
	my %ksymtab = (); # names that appear in __ksymtab_
	my %ref = (); # $ref{$name} exists if there is a true external reference to $name
	my %export = (); # $export{$name} exists if there is an EXPORT_... of $name

	my %nmexception = (
	'fs/ext3/bitmap' => 1,
	'fs/ext4/bitmap' => 1,
	'arch/x86/lib/thunk_32' => 1,
	'arch/x86/lib/cmpxchg' => 1,
	'arch/x86/vdso/vdso32/note' => 1,
	'lib/irq_regs' => 1,
	'usr/initramfs_data' => 1,
	'drivers/scsi/aic94xx/aic94xx_dump' => 1,
	'drivers/scsi/libsas/sas_dump' => 1,
	'lib/dec_and_lock' => 1,
	'drivers/ide/ide-probe-mini' => 1,
	'usr/initramfs_data' => 1,
	'drivers/acpi/acpia/exdump' => 1,
	'drivers/acpi/acpia/rsdump' => 1,
	'drivers/acpi/acpia/nsdumpdv' => 1,
	'drivers/acpi/acpia/nsdump' => 1,
	'arch/ia64/sn/kernel/sn2/io' => 1,
	'arch/ia64/kernel/gate-data' => 1,
	'security/capability' => 1,
	'fs/ntfs/sysctl' => 1,
	'fs/jfs/jfs_debug' => 1,
	);

	my %nameexception = (
	'mod_use_count_' => 1,
	'__initramfs_end' => 1,
	'__initramfs_start' => 1,
	'_einittext' => 1,
	'_sinittext' => 1,
	'kallsyms_names' => 1,
	'kallsyms_num_syms' => 1,
	'kallsyms_addresses'=> 1,
	'kallsyms_offsets' => 1,
	'kallsyms_relative_base'=> 1,
	'__this_module' => 1,
	'_etext' => 1,
	'_edata' => 1,
	'_end' => 1,
	'__bss_start' => 1,
	'_text' => 1,
	'_stext' => 1,
	'__gp' => 1,
	'ia64_unw_start' => 1,
	'ia64_unw_end' => 1,
	'__init_begin' => 1,
	'__init_end' => 1,
	'__bss_stop' => 1,
	'__nosave_begin' => 1,
	'__nosave_end' => 1,
	'pg0' => 1,
	'vdso_enabled' => 1,
	'__stack_chk_fail' => 1,
	'VDSO32_PRELINK' => 1,
	'VDSO32_vsyscall' => 1,
	'VDSO32_rt_sigreturn'=>1,
	'VDSO32_sigreturn' => 1,
	);


	&find(\&linux_objects, '.'); # find the objects and do_nm on them
	&list_multiply_defined();
	&resolve_external_references();
	&list_extra_externals();

	exit(0);

	sub linux_objects
	{
	# Select objects, ignoring objects which are only created by
	# merging other objects. Also ignore all of modules, scripts
	# and compressed. Most conglomerate objects are handled by do_nm,
	# this list only contains the special cases. These include objects
	# that are linked from just one other object and objects for which
	# there is really no permanent source file.
	my $basename = $_;
	$_ = $File::Find::name;
	s:^\./::;
	if (/.*\.o$/ &&
	! (
	m:/built-in.o$:
	\|\| m:arch/x86/vdso/:
	\|\| m:arch/x86/boot/:
	\|\| m:arch/ia64/ia32/ia32.o$:
	\|\| m:arch/ia64/kernel/gate-syms.o$:
	\|\| m:arch/ia64/lib/__divdi3.o$:
	\|\| m:arch/ia64/lib/__divsi3.o$:
	\|\| m:arch/ia64/lib/__moddi3.o$:
	\|\| m:arch/ia64/lib/__modsi3.o$:
	\|\| m:arch/ia64/lib/__udivdi3.o$:
	\|\| m:arch/ia64/lib/__udivsi3.o$:
	\|\| m:arch/ia64/lib/__umoddi3.o$:
	\|\| m:arch/ia64/lib/__umodsi3.o$:
	\|\| m:arch/ia64/scripts/check_gas_for_hint.o$:
	\|\| m:arch/ia64/sn/kernel/xp.o$:
	\|\| m:boot/bbootsect.o$:
	\|\| m:boot/bsetup.o$:
	\|\| m:/bootsect.o$:
	\|\| m:/boot/setup.o$:
	\|\| m:/compressed/:
	\|\| m:drivers/cdrom/driver.o$:
	\|\| m:drivers/char/drm/tdfx_drv.o$:
	\|\| m:drivers/ide/ide-detect.o$:
	\|\| m:drivers/ide/pci/idedriver-pci.o$:
	\|\| m:drivers/media/media.o$:
	\|\| m:drivers/scsi/sd_mod.o$:
	\|\| m:drivers/video/video.o$:
	\|\| m:fs/devpts/devpts.o$:
	\|\| m:fs/exportfs/exportfs.o$:
	\|\| m:fs/hugetlbfs/hugetlbfs.o$:
	\|\| m:fs/msdos/msdos.o$:
	\|\| m:fs/nls/nls.o$:
	\|\| m:fs/ramfs/ramfs.o$:
	\|\| m:fs/romfs/romfs.o$:
	\|\| m:fs/vfat/vfat.o$:
	\|\| m:init/mounts.o$:
	\|\| m:^modules/:
	\|\| m:net/netlink/netlink.o$:
	\|\| m:net/sched/sched.o$:
	\|\| m:/piggy.o$:
	\|\| m:^scripts/:
	\|\| m:sound/.*/snd-:
	\|\| m:^.*/\.tmp_:
	\|\| m:^\.tmp_:
	\|\| m:/vmlinux-obj.o$:
	\|\| m:^tools/:
	)
	) {
	do_nm($basename, $_);
	}
	$_ = $basename; # File::Find expects $_ untouched (undocumented)
	}

	sub do_nm
	{
	my ($basename, $fullname) = @_;
	my ($source, $type, $name);
	if (! -e $basename) {
	printf STDERR "$basename does not exist\n";
	return;
	}
	if ($fullname !~ /\.o$/) {
	printf STDERR "$fullname is not an object file\n";
	return;
	}
	($source = $basename) =~ s/\.o$//;
	if (-e "$source.c" \|\| -e "$source.S") {
	$source = "$objtree$File::Find::dir/$source";
	} else {
	$source = "$srctree$File::Find::dir/$source";
	}
	if (! -e "$source.c" && ! -e "$source.S") {
	# No obvious source, exclude the object if it is conglomerate
	open(my $objdumpdata, "$objdump $basename\|")
	or die "$objdump $fullname failed $!\n";

	my $comment;
	while (<$objdumpdata>) {
	chomp();
	if (/^In archive/) {
	# Archives are always conglomerate
	$comment = "GCC:GCC:";
	last;
	}
	next if (! /^[ 0-9a-f]{5,} /);
	$comment .= substr($_, 43);
	}
	close($objdumpdata);

	if (!defined($comment) \|\| $comment !~ /GCC\:.*GCC\:/m) {
	printf STDERR "No source file found for $fullname\n";
	}
	return;
	}
	open (my $nmdata, "$nm $basename\|")
	or die "$nm $fullname failed $!\n";

	my @nmdata;
	while (<$nmdata>) {
	chop;
	($type, $name) = (split(/ +/, $_, 3))[1..2];
	# Expected types
	# A absolute symbol
	# B weak external reference to data that has been resolved
	# C global variable, uninitialised
	# D global variable, initialised
	# G global variable, initialised, small data section
	# R global array, initialised
	# S global variable, uninitialised, small bss
	# T global label/procedure
	# U external reference
	# W weak external reference to text that has been resolved
	# V similar to W, but the value of the weak symbol becomes zero with no error.
	# a assembler equate
	# b static variable, uninitialised
	# d static variable, initialised
	# g static variable, initialised, small data section
	# r static array, initialised
	# s static variable, uninitialised, small bss
	# t static label/procedures
	# w weak external reference to text that has not been resolved
	# v similar to w
	# ? undefined type, used a lot by modules
	if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) {
	printf STDERR "nm output for $fullname contains unknown type '$_'\n";
	}
	elsif ($name =~ /\./) {
	# name with '.' is local static
	}
	else {
	$type = 'R' if ($type eq '?'); # binutils replaced ? with R at one point
	# binutils keeps changing the type for exported symbols, force it to R
	$type = 'R' if ($name =~ /^__ksymtab/ \|\| $name =~ /^__kstrtab/);
	$name =~ s/_R[a-f0-9]{8}$//; # module versions adds this
	if ($type =~ /[ABCDGRSTWV]/ &&
	$name ne 'init_module' &&
	$name ne 'cleanup_module' &&
	$name ne 'Using_Versions' &&
	$name !~ /^Version_[0-9]+$/ &&
	$name !~ /^__parm_/ &&
	$name !~ /^__kstrtab/ &&
	$name !~ /^__ksymtab/ &&
	$name !~ /^__kcrctab_/ &&
	$name !~ /^__exitcall_/ &&
	$name !~ /^__initcall_/ &&
	$name !~ /^__kdb_initcall_/ &&
	$name !~ /^__kdb_exitcall_/ &&
	$name !~ /^__module_/ &&
	$name !~ /^__mod_/ &&
	$name !~ /^__crc_/ &&
	$name ne '__this_module' &&
	$name ne 'kernel_version') {
	if (!exists($def{$name})) {
	$def{$name} = [];
	}
	push(@{$def{$name}}, $fullname);
	}
	push(@nmdata, "$type $name");
	if ($name =~ /^__ksymtab_/) {
	$name = substr($name, 10);
	if (!exists($ksymtab{$name})) {
	$ksymtab{$name} = [];
	}
	push(@{$ksymtab{$name}}, $fullname);
	}
	}
	}
	close($nmdata);

	if ($#nmdata < 0) {
	printf "No nm data for $fullname\n"
	unless $nmexception{$fullname};
	return;
	}
	$nmdata{$fullname} = \@nmdata;
	}

	sub drop_def
	{
	my ($object, $name) = @_;
	my $nmdata = $nmdata{$object};
	my ($i, $j);
	for ($i = 0; $i <= $#{$nmdata}; ++$i) {
	if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {
	splice(@{$nmdata{$object}}, $i, 1);
	my $def = $def{$name};
	for ($j = 0; $j < $#{$def{$name}}; ++$j) {
	if ($def{$name}[$j] eq $object) {
	splice(@{$def{$name}}, $j, 1);
	}
	}
	last;
	}
	}
	}

	sub list_multiply_defined
	{
	foreach my $name (keys(%def)) {
	if ($#{$def{$name}} > 0) {
	# Special case for cond_syscall
	if ($#{$def{$name}} == 1 &&
	($name =~ /^sys_/ \|\| $name =~ /^compat_sys_/ \|\|
	$name =~ /^sys32_/)) {
	if($def{$name}[0] eq "kernel/sys_ni.o" \|\|
	$def{$name}[1] eq "kernel/sys_ni.o") {
	&drop_def("kernel/sys_ni.o", $name);
	next;
	}
	}

	printf "$name is multiply defined in :-\n";
	foreach my $module (@{$def{$name}}) {
	printf "\t$module\n";
	}
	}
	}
	}

	sub resolve_external_references
	{
	my ($kstrtab, $ksymtab, $export);

	printf "\n";
	foreach my $object (keys(%nmdata)) {
	my $nmdata = $nmdata{$object};
	for (my $i = 0; $i <= $#{$nmdata}; ++$i) {
	my ($type, $name) = split(' ', $nmdata->[$i], 2);
	if ($type eq "U" \|\| $type eq "w") {
	if (exists($def{$name}) \|\| exists($ksymtab{$name})) {
	# add the owning object to the nmdata
	$nmdata->[$i] = "$type $name $object";
	# only count as a reference if it is not EXPORT_...
	$kstrtab = "R __kstrtab_$name";
	$ksymtab = "R __ksymtab_$name";
	$export = 0;
	for (my $j = 0; $j <= $#{$nmdata}; ++$j) {
	if ($nmdata->[$j] eq $kstrtab \|\|
	$nmdata->[$j] eq $ksymtab) {
	$export = 1;
	last;
	}
	}
	if ($export) {
	$export{$name} = "";
	}
	else {
	$ref{$name} = ""
	}
	}
	elsif ( ! $nameexception{$name}
	&& $name !~ /^__sched_text_/
	&& $name !~ /^__start_/
	&& $name !~ /^__end_/
	&& $name !~ /^__stop_/
	&& $name !~ /^__scheduling_functions_.*_here/
	&& $name !~ /^__.*initcall_/
	&& $name !~ /^__.*per_cpu_start/
	&& $name !~ /^__.*per_cpu_end/
	&& $name !~ /^__alt_instructions/
	&& $name !~ /^__setup_/
	&& $name !~ /^__mod_timer/
	&& $name !~ /^__mod_page_state/
	&& $name !~ /^init_module/
	&& $name !~ /^cleanup_module/
	) {
	printf "Cannot resolve ";
	printf "weak " if ($type eq "w");
	printf "reference to $name from $object\n";
	}
	}
	}
	}
	}

	sub list_extra_externals
	{
	my %noref = ();

	foreach my $name (keys(%def)) {
	if (! exists($ref{$name})) {
	my @module = @{$def{$name}};
	foreach my $module (@module) {
	if (! exists($noref{$module})) {
	$noref{$module} = [];
	}
	push(@{$noref{$module}}, $name);
	}
	}
	}
	if (%noref) {
	printf "\nExternally defined symbols with no external references\n";
	foreach my $module (sort(keys(%noref))) {
	printf " $module\n";
	foreach (sort(@{$noref{$module}})) {
	my $export;
	if (exists($export{$_})) {
	$export = " (export only)";
	} else {
	$export = "";
	}
	printf " $_$export\n";
	}
	}
	}
	}