kconfig: use calloc() for expr allocation
[linux-2.6.git] / scripts / namespace.pl
1 #!/usr/bin/perl -w
2 #
3 #       namespace.pl.  Mon Aug 30 2004
4 #
5 #       Perform a name space analysis on the linux kernel.
6 #
7 #       Copyright Keith Owens <kaos@ocs.com.au>.  GPL.
8 #
9 #       Invoke by changing directory to the top of the kernel object
10 #       tree then namespace.pl, no parameters.
11 #
12 #       Tuned for 2.1.x kernels with the new module handling, it will
13 #       work with 2.0 kernels as well.
14 #
15 #       Last change 2.6.9-rc1, adding support for separate source and object
16 #       trees.
17 #
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
21 #       and modules.
22 #
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
27 #       something like
28 #
29 #       #ifndef CONFIG_...
30 #       static
31 #       #endif
32 #       symbol_definition;
33 #
34 #       so the symbols are defined as static unless a particular
35 #       CONFIG_... requires it to be external.
36 #
37 #       A symbol that is suffixed with '(export only)' has these properties
38 #
39 #       * It is global.
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.
43 #
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.
46 #
47 #
48 #       Name space analysis and cleanup is an iterative process.  You cannot
49 #       expect to find all the problems in a single pass.
50 #
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
54 #         as necessary.
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
62 #         result.
63 #
64
65 require 5;      # at least perl 5
66 use strict;
67 use File::Find;
68
69 my $nm = ($ENV{'NM'} || "nm") . " -p";
70 my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment";
71 my $srctree = "";
72 my $objtree = "";
73 $srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
74 $objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));
75
76 if ($#ARGV != -1) {
77         print STDERR "usage: $0 takes no parameters\n";
78         die("giving up\n");
79 }
80
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
86
87 my %nmexception = (
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,
93     'lib/irq_regs'                      => 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,
109 );
110
111 my %nameexception = (
112     'mod_use_count_'     => 1,
113     '__initramfs_end'   => 1,
114     '__initramfs_start' => 1,
115     '_einittext'        => 1,
116     '_sinittext'        => 1,
117     'kallsyms_names'    => 1,
118     'kallsyms_num_syms' => 1,
119     'kallsyms_addresses'=> 1,
120     '__this_module'     => 1,
121     '_etext'            => 1,
122     '_edata'            => 1,
123     '_end'              => 1,
124     '__bss_start'       => 1,
125     '_text'             => 1,
126     '_stext'            => 1,
127     '__gp'              => 1,
128     'ia64_unw_start'    => 1,
129     'ia64_unw_end'      => 1,
130     '__init_begin'      => 1,
131     '__init_end'        => 1,
132     '__bss_stop'        => 1,
133     '__nosave_begin'    => 1,
134     '__nosave_end'      => 1,
135     'pg0'               => 1,
136     'vdso_enabled'      => 1,
137     '__stack_chk_fail'  => 1,
138     'VDSO32_PRELINK'    => 1,
139     'VDSO32_vsyscall'   => 1,
140     'VDSO32_rt_sigreturn'=>1,
141     'VDSO32_sigreturn'  => 1,
142 );
143
144
145 &find(\&linux_objects, '.');    # find the objects and do_nm on them
146 &list_multiply_defined();
147 &resolve_external_references();
148 &list_extra_externals();
149
150 exit(0);
151
152 sub linux_objects
153 {
154         # Select objects, ignoring objects which are only created by
155         # merging other objects.  Also ignore all of modules, scripts
156         # and compressed.  Most conglomerate objects are handled by do_nm,
157         # this list only contains the special cases.  These include objects
158         # that are linked from just one other object and objects for which
159         # there is really no permanent source file.
160         my $basename = $_;
161         $_ = $File::Find::name;
162         s:^\./::;
163         if (/.*\.o$/ &&
164                 ! (
165                 m:/built-in.o$:
166                 || m:arch/x86/vdso/:
167                 || m:arch/x86/boot/:
168                 || m:arch/ia64/ia32/ia32.o$:
169                 || m:arch/ia64/kernel/gate-syms.o$:
170                 || m:arch/ia64/lib/__divdi3.o$:
171                 || m:arch/ia64/lib/__divsi3.o$:
172                 || m:arch/ia64/lib/__moddi3.o$:
173                 || m:arch/ia64/lib/__modsi3.o$:
174                 || m:arch/ia64/lib/__udivdi3.o$:
175                 || m:arch/ia64/lib/__udivsi3.o$:
176                 || m:arch/ia64/lib/__umoddi3.o$:
177                 || m:arch/ia64/lib/__umodsi3.o$:
178                 || m:arch/ia64/scripts/check_gas_for_hint.o$:
179                 || m:arch/ia64/sn/kernel/xp.o$:
180                 || m:boot/bbootsect.o$:
181                 || m:boot/bsetup.o$:
182                 || m:/bootsect.o$:
183                 || m:/boot/setup.o$:
184                 || m:/compressed/:
185                 || m:drivers/cdrom/driver.o$:
186                 || m:drivers/char/drm/tdfx_drv.o$:
187                 || m:drivers/ide/ide-detect.o$:
188                 || m:drivers/ide/pci/idedriver-pci.o$:
189                 || m:drivers/media/media.o$:
190                 || m:drivers/scsi/sd_mod.o$:
191                 || m:drivers/video/video.o$:
192                 || m:fs/devpts/devpts.o$:
193                 || m:fs/exportfs/exportfs.o$:
194                 || m:fs/hugetlbfs/hugetlbfs.o$:
195                 || m:fs/msdos/msdos.o$:
196                 || m:fs/nls/nls.o$:
197                 || m:fs/ramfs/ramfs.o$:
198                 || m:fs/romfs/romfs.o$:
199                 || m:fs/vfat/vfat.o$:
200                 || m:init/mounts.o$:
201                 || m:^modules/:
202                 || m:net/netlink/netlink.o$:
203                 || m:net/sched/sched.o$:
204                 || m:/piggy.o$:
205                 || m:^scripts/:
206                 || m:sound/.*/snd-:
207                 || m:^.*/\.tmp_:
208                 || m:^\.tmp_:
209                 || m:/vmlinux-obj.o$:
210                 || m:^tools/:
211                 )
212         ) {
213                 do_nm($basename, $_);
214         }
215         $_ = $basename;         # File::Find expects $_ untouched (undocumented)
216 }
217
218 sub do_nm
219 {
220         my ($basename, $fullname) = @_;
221         my ($source, $type, $name);
222         if (! -e $basename) {
223                 printf STDERR "$basename does not exist\n";
224                 return;
225         }
226         if ($fullname !~ /\.o$/) {
227                 printf STDERR "$fullname is not an object file\n";
228                 return;
229         }
230         ($source = $basename) =~ s/\.o$//;
231         if (-e "$source.c" || -e "$source.S") {
232                 $source = "$objtree$File::Find::dir/$source";
233         } else {
234                 $source = "$srctree$File::Find::dir/$source";
235         }
236         if (! -e "$source.c" && ! -e "$source.S") {
237                 # No obvious source, exclude the object if it is conglomerate
238                 open(my $objdumpdata, "$objdump $basename|")
239                     or die "$objdump $fullname failed $!\n";
240
241                 my $comment;
242                 while (<$objdumpdata>) {
243                         chomp();
244                         if (/^In archive/) {
245                                 # Archives are always conglomerate
246                                 $comment = "GCC:GCC:";
247                                 last;
248                         }
249                         next if (! /^[ 0-9a-f]{5,} /);
250                         $comment .= substr($_, 43);
251                 }
252                 close($objdumpdata);
253
254                 if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) {
255                         printf STDERR "No source file found for $fullname\n";
256                 }
257                 return;
258         }
259         open (my $nmdata, "$nm $basename|")
260             or die "$nm $fullname failed $!\n";
261
262         my @nmdata;
263         while (<$nmdata>) {
264                 chop;
265                 ($type, $name) = (split(/ +/, $_, 3))[1..2];
266                 # Expected types
267                 # A absolute symbol
268                 # B weak external reference to data that has been resolved
269                 # C global variable, uninitialised
270                 # D global variable, initialised
271                 # G global variable, initialised, small data section
272                 # R global array, initialised
273                 # S global variable, uninitialised, small bss
274                 # T global label/procedure
275                 # U external reference
276                 # W weak external reference to text that has been resolved
277                 # V similar to W, but the value of the weak symbol becomes zero with no error.
278                 # a assembler equate
279                 # b static variable, uninitialised
280                 # d static variable, initialised
281                 # g static variable, initialised, small data section
282                 # r static array, initialised
283                 # s static variable, uninitialised, small bss
284                 # t static label/procedures
285                 # w weak external reference to text that has not been resolved
286                 # v similar to w
287                 # ? undefined type, used a lot by modules
288                 if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) {
289                         printf STDERR "nm output for $fullname contains unknown type '$_'\n";
290                 }
291                 elsif ($name =~ /\./) {
292                         # name with '.' is local static
293                 }
294                 else {
295                         $type = 'R' if ($type eq '?');  # binutils replaced ? with R at one point
296                         # binutils keeps changing the type for exported symbols, force it to R
297                         $type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/);
298                         $name =~ s/_R[a-f0-9]{8}$//;    # module versions adds this
299                         if ($type =~ /[ABCDGRSTWV]/ &&
300                                 $name ne 'init_module' &&
301                                 $name ne 'cleanup_module' &&
302                                 $name ne 'Using_Versions' &&
303                                 $name !~ /^Version_[0-9]+$/ &&
304                                 $name !~ /^__parm_/ &&
305                                 $name !~ /^__kstrtab/ &&
306                                 $name !~ /^__ksymtab/ &&
307                                 $name !~ /^__kcrctab_/ &&
308                                 $name !~ /^__exitcall_/ &&
309                                 $name !~ /^__initcall_/ &&
310                                 $name !~ /^__kdb_initcall_/ &&
311                                 $name !~ /^__kdb_exitcall_/ &&
312                                 $name !~ /^__module_/ &&
313                                 $name !~ /^__mod_/ &&
314                                 $name !~ /^__crc_/ &&
315                                 $name ne '__this_module' &&
316                                 $name ne 'kernel_version') {
317                                 if (!exists($def{$name})) {
318                                         $def{$name} = [];
319                                 }
320                                 push(@{$def{$name}}, $fullname);
321                         }
322                         push(@nmdata, "$type $name");
323                         if ($name =~ /^__ksymtab_/) {
324                                 $name = substr($name, 10);
325                                 if (!exists($ksymtab{$name})) {
326                                         $ksymtab{$name} = [];
327                                 }
328                                 push(@{$ksymtab{$name}}, $fullname);
329                         }
330                 }
331         }
332         close($nmdata);
333
334         if ($#nmdata < 0) {
335             printf "No nm data for $fullname\n"
336                 unless $nmexception{$fullname};
337             return;
338         }
339         $nmdata{$fullname} = \@nmdata;
340 }
341
342 sub drop_def
343 {
344         my ($object, $name) = @_;
345         my $nmdata = $nmdata{$object};
346         my ($i, $j);
347         for ($i = 0; $i <= $#{$nmdata}; ++$i) {
348                 if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {
349                         splice(@{$nmdata{$object}}, $i, 1);
350                         my $def = $def{$name};
351                         for ($j = 0; $j < $#{$def{$name}}; ++$j) {
352                                 if ($def{$name}[$j] eq $object) {
353                                         splice(@{$def{$name}}, $j, 1);
354                                 }
355                         }
356                         last;
357                 }
358         }
359 }
360
361 sub list_multiply_defined
362 {
363         foreach my $name (keys(%def)) {
364                 if ($#{$def{$name}} > 0) {
365                         # Special case for cond_syscall
366                         if ($#{$def{$name}} == 1 &&
367                            ($name =~ /^sys_/ || $name =~ /^compat_sys_/ ||
368                             $name =~ /^sys32_/)) {
369                                 if($def{$name}[0] eq "kernel/sys_ni.o" ||
370                                    $def{$name}[1] eq "kernel/sys_ni.o") {
371                                         &drop_def("kernel/sys_ni.o", $name);
372                                         next;
373                                 }
374                         }
375
376                         printf "$name is multiply defined in :-\n";
377                         foreach my $module (@{$def{$name}}) {
378                                 printf "\t$module\n";
379                         }
380                 }
381         }
382 }
383
384 sub resolve_external_references
385 {
386         my ($kstrtab, $ksymtab, $export);
387
388         printf "\n";
389         foreach my $object (keys(%nmdata)) {
390                 my $nmdata = $nmdata{$object};
391                 for (my $i = 0; $i <= $#{$nmdata}; ++$i) {
392                         my ($type, $name) = split(' ', $nmdata->[$i], 2);
393                         if ($type eq "U" || $type eq "w") {
394                                 if (exists($def{$name}) || exists($ksymtab{$name})) {
395                                         # add the owning object to the nmdata
396                                         $nmdata->[$i] = "$type $name $object";
397                                         # only count as a reference if it is not EXPORT_...
398                                         $kstrtab = "R __kstrtab_$name";
399                                         $ksymtab = "R __ksymtab_$name";
400                                         $export = 0;
401                                         for (my $j = 0; $j <= $#{$nmdata}; ++$j) {
402                                                 if ($nmdata->[$j] eq $kstrtab ||
403                                                     $nmdata->[$j] eq $ksymtab) {
404                                                         $export = 1;
405                                                         last;
406                                                 }
407                                         }
408                                         if ($export) {
409                                                 $export{$name} = "";
410                                         }
411                                         else {
412                                                 $ref{$name} = ""
413                                         }
414                                 }
415                                 elsif ( ! $nameexception{$name}
416                                         && $name !~ /^__sched_text_/
417                                         && $name !~ /^__start_/
418                                         && $name !~ /^__end_/
419                                         && $name !~ /^__stop_/
420                                         && $name !~ /^__scheduling_functions_.*_here/
421                                         && $name !~ /^__.*initcall_/
422                                         && $name !~ /^__.*per_cpu_start/
423                                         && $name !~ /^__.*per_cpu_end/
424                                         && $name !~ /^__alt_instructions/
425                                         && $name !~ /^__setup_/
426                                         && $name !~ /^__mod_timer/
427                                         && $name !~ /^__mod_page_state/
428                                         && $name !~ /^init_module/
429                                         && $name !~ /^cleanup_module/
430                                 ) {
431                                         printf "Cannot resolve ";
432                                         printf "weak " if ($type eq "w");
433                                         printf "reference to $name from $object\n";
434                                 }
435                         }
436                 }
437         }
438 }
439
440 sub list_extra_externals
441 {
442         my %noref = ();
443
444         foreach my $name (keys(%def)) {
445                 if (! exists($ref{$name})) {
446                         my @module = @{$def{$name}};
447                         foreach my $module (@module) {
448                                 if (! exists($noref{$module})) {
449                                         $noref{$module} = [];
450                                 }
451                                 push(@{$noref{$module}}, $name);
452                         }
453                 }
454         }
455         if (%noref) {
456                 printf "\nExternally defined symbols with no external references\n";
457                 foreach my $module (sort(keys(%noref))) {
458                         printf "  $module\n";
459                         foreach (sort(@{$noref{$module}})) {
460                             my $export;
461                             if (exists($export{$_})) {
462                                 $export = " (export only)";
463                             } else {
464                                 $export = "";
465                             }
466                             printf "    $_$export\n";
467                         }
468                 }
469         }
470 }