|  | #!/usr/bin/perl -w | 
|  | # | 
|  | #	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. | 
|  | # | 
|  |  | 
|  | require 5;	# at least perl 5 | 
|  | 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, | 
|  | '__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"; | 
|  | } | 
|  | } | 
|  | } | 
|  | } |