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1da177e4 LT |
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 | ||
3a25f0b1 AB |
69 | my $nm = ($ENV{'NM'} || "nm") . " -p"; |
70 | my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment"; | |
1da177e4 LT |
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 | ||
43f683c9 SH |
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 | ); | |
137 | ||
138 | ||
1da177e4 LT |
139 | &find(\&linux_objects, '.'); # find the objects and do_nm on them |
140 | &list_multiply_defined(); | |
141 | &resolve_external_references(); | |
142 | &list_extra_externals(); | |
143 | ||
144 | exit(0); | |
145 | ||
146 | sub linux_objects | |
147 | { | |
148 | # Select objects, ignoring objects which are only created by | |
149 | # merging other objects. Also ignore all of modules, scripts | |
150 | # and compressed. Most conglomerate objects are handled by do_nm, | |
151 | # this list only contains the special cases. These include objects | |
152 | # that are linked from just one other object and objects for which | |
153 | # there is really no permanent source file. | |
154 | my $basename = $_; | |
155 | $_ = $File::Find::name; | |
156 | s:^\./::; | |
157 | if (/.*\.o$/ && | |
158 | ! ( | |
159 | m:/built-in.o$: | |
d2c75f2f | 160 | || m:arch/x86/kernel/vsyscall-syms.o$: |
1da177e4 LT |
161 | || m:arch/ia64/ia32/ia32.o$: |
162 | || m:arch/ia64/kernel/gate-syms.o$: | |
163 | || m:arch/ia64/lib/__divdi3.o$: | |
164 | || m:arch/ia64/lib/__divsi3.o$: | |
165 | || m:arch/ia64/lib/__moddi3.o$: | |
166 | || m:arch/ia64/lib/__modsi3.o$: | |
167 | || m:arch/ia64/lib/__udivdi3.o$: | |
168 | || m:arch/ia64/lib/__udivsi3.o$: | |
169 | || m:arch/ia64/lib/__umoddi3.o$: | |
170 | || m:arch/ia64/lib/__umodsi3.o$: | |
171 | || m:arch/ia64/scripts/check_gas_for_hint.o$: | |
172 | || m:arch/ia64/sn/kernel/xp.o$: | |
173 | || m:boot/bbootsect.o$: | |
174 | || m:boot/bsetup.o$: | |
175 | || m:/bootsect.o$: | |
176 | || m:/boot/setup.o$: | |
177 | || m:/compressed/: | |
178 | || m:drivers/cdrom/driver.o$: | |
179 | || m:drivers/char/drm/tdfx_drv.o$: | |
180 | || m:drivers/ide/ide-detect.o$: | |
181 | || m:drivers/ide/pci/idedriver-pci.o$: | |
182 | || m:drivers/media/media.o$: | |
183 | || m:drivers/scsi/sd_mod.o$: | |
184 | || m:drivers/video/video.o$: | |
185 | || m:fs/devpts/devpts.o$: | |
186 | || m:fs/exportfs/exportfs.o$: | |
187 | || m:fs/hugetlbfs/hugetlbfs.o$: | |
188 | || m:fs/msdos/msdos.o$: | |
189 | || m:fs/nls/nls.o$: | |
190 | || m:fs/ramfs/ramfs.o$: | |
191 | || m:fs/romfs/romfs.o$: | |
192 | || m:fs/vfat/vfat.o$: | |
193 | || m:init/mounts.o$: | |
194 | || m:^modules/: | |
195 | || m:net/netlink/netlink.o$: | |
196 | || m:net/sched/sched.o$: | |
197 | || m:/piggy.o$: | |
198 | || m:^scripts/: | |
199 | || m:sound/.*/snd-: | |
200 | || m:^.*/\.tmp_: | |
201 | || m:^\.tmp_: | |
202 | || m:/vmlinux-obj.o$: | |
203 | ) | |
204 | ) { | |
205 | do_nm($basename, $_); | |
206 | } | |
207 | $_ = $basename; # File::Find expects $_ untouched (undocumented) | |
208 | } | |
209 | ||
210 | sub do_nm | |
211 | { | |
212 | my ($basename, $fullname) = @_; | |
213 | my ($source, $type, $name); | |
214 | if (! -e $basename) { | |
215 | printf STDERR "$basename does not exist\n"; | |
216 | return; | |
217 | } | |
218 | if ($fullname !~ /\.o$/) { | |
219 | printf STDERR "$fullname is not an object file\n"; | |
220 | return; | |
221 | } | |
c25f4157 AW |
222 | ($source = $basename) =~ s/\.o$//; |
223 | if (-e "$source.c" || -e "$source.S") { | |
224 | $source = "$objtree$File::Find::dir/$source"; | |
1da177e4 | 225 | } else { |
c25f4157 | 226 | $source = "$srctree$File::Find::dir/$source"; |
1da177e4 LT |
227 | } |
228 | if (! -e "$source.c" && ! -e "$source.S") { | |
229 | # No obvious source, exclude the object if it is conglomerate | |
86d08e56 SH |
230 | open(my $objdumpdata, "$objdump $basename|") |
231 | or die "$objdump $fullname failed $!\n"; | |
232 | ||
1da177e4 | 233 | my $comment; |
86d08e56 | 234 | while (<$objdumpdata>) { |
1da177e4 LT |
235 | chomp(); |
236 | if (/^In archive/) { | |
237 | # Archives are always conglomerate | |
238 | $comment = "GCC:GCC:"; | |
239 | last; | |
240 | } | |
241 | next if (! /^[ 0-9a-f]{5,} /); | |
242 | $comment .= substr($_, 43); | |
243 | } | |
86d08e56 SH |
244 | close($objdumpdata); |
245 | ||
1da177e4 LT |
246 | if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) { |
247 | printf STDERR "No source file found for $fullname\n"; | |
248 | } | |
249 | return; | |
250 | } | |
86d08e56 SH |
251 | open (my $nmdata, "$nm $basename|") |
252 | or die "$nm $fullname failed $!\n"; | |
253 | ||
1da177e4 | 254 | my @nmdata; |
86d08e56 | 255 | while (<$nmdata>) { |
1da177e4 LT |
256 | chop; |
257 | ($type, $name) = (split(/ +/, $_, 3))[1..2]; | |
258 | # Expected types | |
259 | # A absolute symbol | |
260 | # B weak external reference to data that has been resolved | |
261 | # C global variable, uninitialised | |
262 | # D global variable, initialised | |
263 | # G global variable, initialised, small data section | |
264 | # R global array, initialised | |
265 | # S global variable, uninitialised, small bss | |
266 | # T global label/procedure | |
267 | # U external reference | |
268 | # W weak external reference to text that has been resolved | |
e8cf9813 | 269 | # V similar to W, but the value of the weak symbol becomes zero with no error. |
1da177e4 LT |
270 | # a assembler equate |
271 | # b static variable, uninitialised | |
272 | # d static variable, initialised | |
273 | # g static variable, initialised, small data section | |
274 | # r static array, initialised | |
275 | # s static variable, uninitialised, small bss | |
276 | # t static label/procedures | |
277 | # w weak external reference to text that has not been resolved | |
e8cf9813 | 278 | # v similar to w |
1da177e4 | 279 | # ? undefined type, used a lot by modules |
e8cf9813 | 280 | if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) { |
1da177e4 LT |
281 | printf STDERR "nm output for $fullname contains unknown type '$_'\n"; |
282 | } | |
283 | elsif ($name =~ /\./) { | |
284 | # name with '.' is local static | |
285 | } | |
286 | else { | |
287 | $type = 'R' if ($type eq '?'); # binutils replaced ? with R at one point | |
288 | # binutils keeps changing the type for exported symbols, force it to R | |
289 | $type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/); | |
290 | $name =~ s/_R[a-f0-9]{8}$//; # module versions adds this | |
e8cf9813 | 291 | if ($type =~ /[ABCDGRSTWV]/ && |
1da177e4 LT |
292 | $name ne 'init_module' && |
293 | $name ne 'cleanup_module' && | |
294 | $name ne 'Using_Versions' && | |
295 | $name !~ /^Version_[0-9]+$/ && | |
296 | $name !~ /^__parm_/ && | |
297 | $name !~ /^__kstrtab/ && | |
298 | $name !~ /^__ksymtab/ && | |
299 | $name !~ /^__kcrctab_/ && | |
300 | $name !~ /^__exitcall_/ && | |
301 | $name !~ /^__initcall_/ && | |
302 | $name !~ /^__kdb_initcall_/ && | |
303 | $name !~ /^__kdb_exitcall_/ && | |
304 | $name !~ /^__module_/ && | |
305 | $name !~ /^__mod_/ && | |
306 | $name !~ /^__crc_/ && | |
307 | $name ne '__this_module' && | |
308 | $name ne 'kernel_version') { | |
309 | if (!exists($def{$name})) { | |
310 | $def{$name} = []; | |
311 | } | |
312 | push(@{$def{$name}}, $fullname); | |
313 | } | |
314 | push(@nmdata, "$type $name"); | |
315 | if ($name =~ /^__ksymtab_/) { | |
316 | $name = substr($name, 10); | |
317 | if (!exists($ksymtab{$name})) { | |
318 | $ksymtab{$name} = []; | |
319 | } | |
320 | push(@{$ksymtab{$name}}, $fullname); | |
321 | } | |
322 | } | |
323 | } | |
86d08e56 SH |
324 | close($nmdata); |
325 | ||
1da177e4 | 326 | if ($#nmdata < 0) { |
43f683c9 SH |
327 | printf "No nm data for $fullname\n" |
328 | unless $nmexception{$fullname}; | |
329 | return; | |
1da177e4 LT |
330 | } |
331 | $nmdata{$fullname} = \@nmdata; | |
332 | } | |
333 | ||
334 | sub drop_def | |
335 | { | |
336 | my ($object, $name) = @_; | |
337 | my $nmdata = $nmdata{$object}; | |
338 | my ($i, $j); | |
339 | for ($i = 0; $i <= $#{$nmdata}; ++$i) { | |
340 | if ($name eq (split(' ', $nmdata->[$i], 2))[1]) { | |
341 | splice(@{$nmdata{$object}}, $i, 1); | |
342 | my $def = $def{$name}; | |
343 | for ($j = 0; $j < $#{$def{$name}}; ++$j) { | |
344 | if ($def{$name}[$j] eq $object) { | |
345 | splice(@{$def{$name}}, $j, 1); | |
346 | } | |
347 | } | |
348 | last; | |
349 | } | |
350 | } | |
351 | } | |
352 | ||
353 | sub list_multiply_defined | |
354 | { | |
86d08e56 | 355 | foreach my $name (keys(%def)) { |
1da177e4 LT |
356 | if ($#{$def{$name}} > 0) { |
357 | # Special case for cond_syscall | |
e8cf9813 AW |
358 | if ($#{$def{$name}} == 1 && $name =~ /^sys_/) { |
359 | if($def{$name}[0] eq "kernel/sys_ni.o" || | |
360 | $def{$name}[1] eq "kernel/sys_ni.o") { | |
361 | &drop_def("kernel/sys_ni.o", $name); | |
362 | next; | |
363 | } | |
1da177e4 LT |
364 | } |
365 | # Special case for i386 entry code | |
366 | if ($#{$def{$name}} == 1 && $name =~ /^__kernel_/ && | |
d2c75f2f TG |
367 | $def{$name}[0] eq "arch/x86/kernel/vsyscall-int80_32.o" && |
368 | $def{$name}[1] eq "arch/x86/kernel/vsyscall-sysenter_32.o") { | |
369 | &drop_def("arch/x86/kernel/vsyscall-sysenter_32.o", $name); | |
1da177e4 LT |
370 | next; |
371 | } | |
86d08e56 | 372 | |
1da177e4 | 373 | printf "$name is multiply defined in :-\n"; |
86d08e56 | 374 | foreach my $module (@{$def{$name}}) { |
1da177e4 LT |
375 | printf "\t$module\n"; |
376 | } | |
377 | } | |
378 | } | |
379 | } | |
380 | ||
381 | sub resolve_external_references | |
382 | { | |
86d08e56 SH |
383 | my ($kstrtab, $ksymtab, $export); |
384 | ||
1da177e4 | 385 | printf "\n"; |
86d08e56 | 386 | foreach my $object (keys(%nmdata)) { |
1da177e4 | 387 | my $nmdata = $nmdata{$object}; |
86d08e56 SH |
388 | for (my $i = 0; $i <= $#{$nmdata}; ++$i) { |
389 | my ($type, $name) = split(' ', $nmdata->[$i], 2); | |
1da177e4 LT |
390 | if ($type eq "U" || $type eq "w") { |
391 | if (exists($def{$name}) || exists($ksymtab{$name})) { | |
392 | # add the owning object to the nmdata | |
393 | $nmdata->[$i] = "$type $name $object"; | |
394 | # only count as a reference if it is not EXPORT_... | |
395 | $kstrtab = "R __kstrtab_$name"; | |
396 | $ksymtab = "R __ksymtab_$name"; | |
397 | $export = 0; | |
86d08e56 | 398 | for (my $j = 0; $j <= $#{$nmdata}; ++$j) { |
1da177e4 LT |
399 | if ($nmdata->[$j] eq $kstrtab || |
400 | $nmdata->[$j] eq $ksymtab) { | |
401 | $export = 1; | |
402 | last; | |
403 | } | |
404 | } | |
405 | if ($export) { | |
406 | $export{$name} = ""; | |
407 | } | |
408 | else { | |
409 | $ref{$name} = "" | |
410 | } | |
411 | } | |
43f683c9 | 412 | elsif ( ! $nameexception{$name} |
1da177e4 LT |
413 | && $name !~ /^__sched_text_/ |
414 | && $name !~ /^__start_/ | |
415 | && $name !~ /^__end_/ | |
416 | && $name !~ /^__stop_/ | |
417 | && $name !~ /^__scheduling_functions_.*_here/ | |
418 | && $name !~ /^__.*initcall_/ | |
419 | && $name !~ /^__.*per_cpu_start/ | |
420 | && $name !~ /^__.*per_cpu_end/ | |
421 | && $name !~ /^__alt_instructions/ | |
422 | && $name !~ /^__setup_/ | |
1da177e4 LT |
423 | && $name !~ /^__mod_timer/ |
424 | && $name !~ /^__mod_page_state/ | |
425 | && $name !~ /^init_module/ | |
426 | && $name !~ /^cleanup_module/ | |
427 | ) { | |
428 | printf "Cannot resolve "; | |
429 | printf "weak " if ($type eq "w"); | |
430 | printf "reference to $name from $object\n"; | |
431 | } | |
432 | } | |
433 | } | |
434 | } | |
435 | } | |
436 | ||
437 | sub list_extra_externals | |
438 | { | |
439 | my %noref = (); | |
86d08e56 SH |
440 | |
441 | foreach my $name (keys(%def)) { | |
1da177e4 | 442 | if (! exists($ref{$name})) { |
86d08e56 SH |
443 | my @module = @{$def{$name}}; |
444 | foreach my $module (@module) { | |
1da177e4 LT |
445 | if (! exists($noref{$module})) { |
446 | $noref{$module} = []; | |
447 | } | |
448 | push(@{$noref{$module}}, $name); | |
449 | } | |
450 | } | |
451 | } | |
452 | if (%noref) { | |
453 | printf "\nExternally defined symbols with no external references\n"; | |
86d08e56 | 454 | foreach my $module (sort(keys(%noref))) { |
1da177e4 LT |
455 | printf " $module\n"; |
456 | foreach (sort(@{$noref{$module}})) { | |
86d08e56 SH |
457 | my $export; |
458 | if (exists($export{$_})) { | |
459 | $export = " (export only)"; | |
460 | } else { | |
461 | $export = ""; | |
462 | } | |
463 | printf " $_$export\n"; | |
1da177e4 LT |
464 | } |
465 | } | |
466 | } | |
467 | } |