3 # namespace.pl. Mon Aug 30 2004
5 # Perform a name space analysis on the linux kernel.
7 # Copyright Keith Owens <kaos@ocs.com.au>. GPL.
9 # Invoke by changing directory to the top of the kernel object
10 # tree then namespace.pl, no parameters.
12 # Tuned for 2.1.x kernels with the new module handling, it will
13 # work with 2.0 kernels as well.
15 # Last change 2.6.9-rc1, adding support for separate source and object
18 # The source must be compiled/assembled first, the object files
19 # are the primary input to this script. Incomplete or missing
20 # objects will result in a flawed analysis. Compile both vmlinux
23 # Even with complete objects, treat the result of the analysis
24 # with caution. Some external references are only used by
25 # certain architectures, others with certain combinations of
26 # configuration parameters. Ideally the source should include
34 # so the symbols are defined as static unless a particular
35 # CONFIG_... requires it to be external.
37 # A symbol that is suffixed with '(export only)' has these properties
40 # * It is marked EXPORT_SYMBOL or EXPORT_SYMBOL_GPL, either in the same
41 # source file or a different source file.
42 # * Given the current .config, nothing uses the symbol.
44 # The symbol is a candidate for conversion to static, plus removal of the
45 # export. But be careful that a different .config might use the symbol.
48 # Name space analysis and cleanup is an iterative process. You cannot
49 # expect to find all the problems in a single pass.
51 # * Identify possibly unnecessary global declarations, verify that they
52 # really are unnecessary and change them to static.
53 # * Compile and fix up gcc warnings about static, removing dead symbols
55 # * make clean and rebuild with different configs (especially
56 # CONFIG_MODULES=n) to see which symbols are being defined when the
57 # config does not require them. These symbols bloat the kernel object
58 # for no good reason, which is frustrating for embedded systems.
59 # * Wrap config sensitive symbols in #ifdef CONFIG_foo, as long as the
60 # code does not get too ugly.
61 # * Repeat the name space analysis until you can live with with the
65 require 5; # at least perl 5
69 my $nm = ($ENV{'NM'} || "nm") . " -p";
70 my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment";
73 $srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
74 $objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));
77 print STDERR
"usage: $0 takes no parameters\n";
81 my %nmdata = (); # nm data for each object
82 my %def = (); # all definitions for each name
83 my %ksymtab = (); # names that appear in __ksymtab_
84 my %ref = (); # $ref{$name} exists if there is a true external reference to $name
85 my %export = (); # $export{$name} exists if there is an EXPORT_... of $name
88 'fs/ext3/bitmap' => 1,
89 'fs/ext4/bitmap' => 1,
90 'arch/x86/lib/thunk_32' => 1,
91 'arch/x86/lib/cmpxchg' => 1,
92 'arch/x86/vdso/vdso32/note' => 1,
94 'usr/initramfs_data' => 1,
95 'drivers/scsi/aic94xx/aic94xx_dump' => 1,
96 'drivers/scsi/libsas/sas_dump' => 1,
97 'lib/dec_and_lock' => 1,
98 'drivers/ide/ide-probe-mini' => 1,
99 'usr/initramfs_data' => 1,
100 'drivers/acpi/acpia/exdump' => 1,
101 'drivers/acpi/acpia/rsdump' => 1,
102 'drivers/acpi/acpia/nsdumpdv' => 1,
103 'drivers/acpi/acpia/nsdump' => 1,
104 'arch/ia64/sn/kernel/sn2/io' => 1,
105 'arch/ia64/kernel/gate-data' => 1,
106 'security/capability' => 1,
107 'fs/ntfs/sysctl' => 1,
108 'fs/jfs/jfs_debug' => 1,
111 my %nameexception = (
112 'mod_use_count_' => 1,
113 '__initramfs_end' => 1,
114 '__initramfs_start' => 1,
117 'kallsyms_names' => 1,
118 'kallsyms_num_syms' => 1,
119 'kallsyms_addresses'=> 1,
120 '__this_module' => 1,
128 'ia64_unw_start' => 1,
133 '__nosave_begin' => 1,
137 '__stack_chk_fail' => 1,
138 'VDSO32_PRELINK' => 1,
139 'VDSO32_vsyscall' => 1,
140 'VDSO32_rt_sigreturn'=>1,
141 'VDSO32_sigreturn' => 1,
144 # Files with exceptions to source file location
146 'net/dccp/dccp_probe.o' => 'probe',
147 'net/dccp/dccp_ipv4.o' => 'ipv4',
148 'net/dccp/dccp_ipv6.o' => 'ipv6',
149 'net/dccp/dccp_diag.o' => 'diag',
150 'drivers/char/hw_random/rng-core.o' => 'core',
151 'fs/fat/msdos.o' => 'namei_msdos',
152 'fs/fat/vfat.o' => 'namei_vfat',
153 'fs/nfs_common/nfs_acl.o' => 'nfsacl',
154 'sound/soundcore.o' => 'sound_core',
155 'drivers/md/dm-mirror.o' => 'dm-raid1',
156 'drivers/message/i2o/i2o_bus.o' => 'bus-osm',
157 'arch/x86/kvm/kvm-amd.o' => 'svm',
158 'arch/x86/kvm/kvm-intel.o' => 'vmx',
159 'arch/x86/crypto/twofish-x86_64.o' => 'twofish-x86_64-asm_64',
160 'arch/x86/crypto/aes-x86_64.o' => 'aes-x86_64-asm_64',
161 'arch/x86/crypto/aesni-intel.o' => 'aesni-intel_asm',
162 'arch/x86/crypto/salsa20-x86_64.o' => 'salsa20-x86_64-asm_64',
165 &find
(\
&linux_objects
, '.'); # find the objects and do_nm on them
166 &list_multiply_defined
();
167 &resolve_external_references
();
168 &list_extra_externals
();
174 # Select objects, ignoring objects which are only created by
175 # merging other objects. Also ignore all of modules, scripts
176 # and compressed. Most conglomerate objects are handled by do_nm,
177 # this list only contains the special cases. These include objects
178 # that are linked from just one other object and objects for which
179 # there is really no permanent source file.
181 $_ = $File::Find
::name
;
188 || m
:arch
/ia64/ia32/ia32
.o
$:
189 || m
:arch
/ia64/kernel
/gate
-syms
.o
$:
190 || m
:arch
/ia64/lib
/__divdi3
.o
$:
191 || m
:arch
/ia64/lib
/__divsi3
.o
$:
192 || m
:arch
/ia64/lib
/__moddi3
.o
$:
193 || m
:arch
/ia64/lib
/__modsi3
.o
$:
194 || m
:arch
/ia64/lib
/__udivdi3
.o
$:
195 || m
:arch
/ia64/lib
/__udivsi3
.o
$:
196 || m
:arch
/ia64/lib
/__umoddi3
.o
$:
197 || m
:arch
/ia64/lib
/__umodsi3
.o
$:
198 || m
:arch
/ia64/scripts
/check_gas_for_hint
.o
$:
199 || m
:arch
/ia64/sn
/kernel/xp.o
$:
200 || m
:boot
/bbootsect
.o
$:
205 || m
:drivers
/cdrom/driver
.o
$:
206 || m
:drivers
/char
/drm
/tdfx_drv
.o
$:
207 || m
:drivers
/ide/ide
-detect
.o
$:
208 || m
:drivers
/ide
/pci
/idedriver
-pci
.o
$:
209 || m
:drivers
/media/media
.o
$:
210 || m
:drivers
/scsi/sd_mod
.o
$:
211 || m
:drivers
/video/video
.o
$:
212 || m
:fs
/devpts/devpts
.o
$:
213 || m
:fs
/exportfs/exportfs
.o
$:
214 || m
:fs
/hugetlbfs/hugetlbfs
.o
$:
215 || m
:fs
/msdos/msdos.o
$:
217 || m
:fs
/ramfs/ramfs
.o
$:
218 || m
:fs
/romfs/romfs
.o
$:
219 || m
:fs
/vfat/vfat
.o
$:
222 || m
:net
/netlink/netlink
.o
$:
223 || m
:net
/sched/sched
.o
$:
229 || m
:/vmlinux
-obj
.o
$:
233 do_nm
($basename, $_);
235 $_ = $basename; # File::Find expects $_ untouched (undocumented)
240 my ($basename, $fullname) = @_;
241 my ($source, $type, $name);
242 if (! -e
$basename) {
243 printf STDERR
"$basename does not exist\n";
246 if ($fullname !~ /\.o$/) {
247 printf STDERR
"$fullname is not an object file\n";
250 ($source = $basename) =~ s/\.o$//;
252 $source = $sourceloc{$fullname} if ($sourceloc{$fullname});
254 if (-e
"$source.c" || -e
"$source.S") {
255 $source = "$objtree$File::Find::dir/$source";
257 $source = "$srctree$File::Find::dir/$source";
260 if (! -e
"$source.c" && ! -e
"$source.S") {
261 # No obvious source, exclude the object if it is conglomerate
262 open(my $objdumpdata, "$objdump $basename|")
263 or die "$objdump $fullname failed $!\n";
266 while (<$objdumpdata>) {
269 # Archives are always conglomerate
270 $comment = "GCC:GCC:";
273 next if (! /^[ 0-9a-f]{5,} /);
274 $comment .= substr($_, 43);
278 if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) {
279 printf STDERR
"No source file found for $fullname\n";
283 open (my $nmdata, "$nm $basename|")
284 or die "$nm $fullname failed $!\n";
289 ($type, $name) = (split(/ +/, $_, 3))[1..2];
292 # B weak external reference to data that has been resolved
293 # C global variable, uninitialised
294 # D global variable, initialised
295 # G global variable, initialised, small data section
296 # R global array, initialised
297 # S global variable, uninitialised, small bss
298 # T global label/procedure
299 # U external reference
300 # W weak external reference to text that has been resolved
301 # V similar to W, but the value of the weak symbol becomes zero with no error.
303 # b static variable, uninitialised
304 # d static variable, initialised
305 # g static variable, initialised, small data section
306 # r static array, initialised
307 # s static variable, uninitialised, small bss
308 # t static label/procedures
309 # w weak external reference to text that has not been resolved
311 # ? undefined type, used a lot by modules
312 if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) {
313 printf STDERR
"nm output for $fullname contains unknown type '$_'\n";
315 elsif ($name =~ /\./) {
316 # name with '.' is local static
319 $type = 'R' if ($type eq '?'); # binutils replaced ? with R at one point
320 # binutils keeps changing the type for exported symbols, force it to R
321 $type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/);
322 $name =~ s/_R[a-f0-9]{8}$//; # module versions adds this
323 if ($type =~ /[ABCDGRSTWV]/ &&
324 $name ne 'init_module' &&
325 $name ne 'cleanup_module' &&
326 $name ne 'Using_Versions' &&
327 $name !~ /^Version_[0-9]+$/ &&
328 $name !~ /^__parm_/ &&
329 $name !~ /^__kstrtab/ &&
330 $name !~ /^__ksymtab/ &&
331 $name !~ /^__kcrctab_/ &&
332 $name !~ /^__exitcall_/ &&
333 $name !~ /^__initcall_/ &&
334 $name !~ /^__kdb_initcall_/ &&
335 $name !~ /^__kdb_exitcall_/ &&
336 $name !~ /^__module_/ &&
337 $name !~ /^__mod_/ &&
338 $name !~ /^__crc_/ &&
339 $name ne '__this_module' &&
340 $name ne 'kernel_version') {
341 if (!exists($def{$name})) {
344 push(@
{$def{$name}}, $fullname);
346 push(@nmdata, "$type $name");
347 if ($name =~ /^__ksymtab_/) {
348 $name = substr($name, 10);
349 if (!exists($ksymtab{$name})) {
350 $ksymtab{$name} = [];
352 push(@
{$ksymtab{$name}}, $fullname);
359 printf "No nm data for $fullname\n"
360 unless $nmexception{$fullname};
363 $nmdata{$fullname} = \
@nmdata;
368 my ($object, $name) = @_;
369 my $nmdata = $nmdata{$object};
371 for ($i = 0; $i <= $#{$nmdata}; ++$i) {
372 if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {
373 splice(@
{$nmdata{$object}}, $i, 1);
374 my $def = $def{$name};
375 for ($j = 0; $j < $#{$def{$name}}; ++$j) {
376 if ($def{$name}[$j] eq $object) {
377 splice(@
{$def{$name}}, $j, 1);
385 sub list_multiply_defined
387 foreach my $name (keys(%def)) {
388 if ($#{$def{$name}} > 0) {
389 # Special case for cond_syscall
390 if ($#{$def{$name}} == 1 &&
391 ($name =~ /^sys_/ || $name =~ /^compat_sys_/ ||
392 $name =~ /^sys32_/)) {
393 if($def{$name}[0] eq "kernel/sys_ni.o" ||
394 $def{$name}[1] eq "kernel/sys_ni.o") {
395 &drop_def
("kernel/sys_ni.o", $name);
400 printf "$name is multiply defined in :-\n";
401 foreach my $module (@
{$def{$name}}) {
402 printf "\t$module\n";
408 sub resolve_external_references
410 my ($kstrtab, $ksymtab, $export);
413 foreach my $object (keys(%nmdata)) {
414 my $nmdata = $nmdata{$object};
415 for (my $i = 0; $i <= $#{$nmdata}; ++$i) {
416 my ($type, $name) = split(' ', $nmdata->[$i], 2);
417 if ($type eq "U" || $type eq "w") {
418 if (exists($def{$name}) || exists($ksymtab{$name})) {
419 # add the owning object to the nmdata
420 $nmdata->[$i] = "$type $name $object";
421 # only count as a reference if it is not EXPORT_...
422 $kstrtab = "R __kstrtab_$name";
423 $ksymtab = "R __ksymtab_$name";
425 for (my $j = 0; $j <= $#{$nmdata}; ++$j) {
426 if ($nmdata->[$j] eq $kstrtab ||
427 $nmdata->[$j] eq $ksymtab) {
439 elsif ( ! $nameexception{$name}
440 && $name !~ /^__sched_text_/
441 && $name !~ /^__start_/
442 && $name !~ /^__end_/
443 && $name !~ /^__stop_/
444 && $name !~ /^__scheduling_functions_.*_here/
445 && $name !~ /^__.*initcall_/
446 && $name !~ /^__.*per_cpu_start/
447 && $name !~ /^__.*per_cpu_end/
448 && $name !~ /^__alt_instructions/
449 && $name !~ /^__setup_/
450 && $name !~ /^__mod_timer/
451 && $name !~ /^__mod_page_state/
452 && $name !~ /^init_module/
453 && $name !~ /^cleanup_module/
455 printf "Cannot resolve ";
456 printf "weak " if ($type eq "w");
457 printf "reference to $name from $object\n";
464 sub list_extra_externals
468 foreach my $name (keys(%def)) {
469 if (! exists($ref{$name})) {
470 my @module = @
{$def{$name}};
471 foreach my $module (@module) {
472 if (! exists($noref{$module})) {
473 $noref{$module} = [];
475 push(@
{$noref{$module}}, $name);
480 printf "\nExternally defined symbols with no external references\n";
481 foreach my $module (sort(keys(%noref))) {
483 foreach (sort(@
{$noref{$module}})) {
485 if (exists($export{$_})) {
486 $export = " (export only)";
490 printf " $_$export\n";