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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 | ||
87 | &find(\&linux_objects, '.'); # find the objects and do_nm on them | |
88 | &list_multiply_defined(); | |
89 | &resolve_external_references(); | |
90 | &list_extra_externals(); | |
91 | ||
92 | exit(0); | |
93 | ||
94 | sub linux_objects | |
95 | { | |
96 | # Select objects, ignoring objects which are only created by | |
97 | # merging other objects. Also ignore all of modules, scripts | |
98 | # and compressed. Most conglomerate objects are handled by do_nm, | |
99 | # this list only contains the special cases. These include objects | |
100 | # that are linked from just one other object and objects for which | |
101 | # there is really no permanent source file. | |
102 | my $basename = $_; | |
103 | $_ = $File::Find::name; | |
104 | s:^\./::; | |
105 | if (/.*\.o$/ && | |
106 | ! ( | |
107 | m:/built-in.o$: | |
108 | || m:arch/i386/kernel/vsyscall-syms.o$: | |
109 | || m:arch/ia64/ia32/ia32.o$: | |
110 | || m:arch/ia64/kernel/gate-syms.o$: | |
111 | || m:arch/ia64/lib/__divdi3.o$: | |
112 | || m:arch/ia64/lib/__divsi3.o$: | |
113 | || m:arch/ia64/lib/__moddi3.o$: | |
114 | || m:arch/ia64/lib/__modsi3.o$: | |
115 | || m:arch/ia64/lib/__udivdi3.o$: | |
116 | || m:arch/ia64/lib/__udivsi3.o$: | |
117 | || m:arch/ia64/lib/__umoddi3.o$: | |
118 | || m:arch/ia64/lib/__umodsi3.o$: | |
119 | || m:arch/ia64/scripts/check_gas_for_hint.o$: | |
120 | || m:arch/ia64/sn/kernel/xp.o$: | |
121 | || m:boot/bbootsect.o$: | |
122 | || m:boot/bsetup.o$: | |
123 | || m:/bootsect.o$: | |
124 | || m:/boot/setup.o$: | |
125 | || m:/compressed/: | |
126 | || m:drivers/cdrom/driver.o$: | |
127 | || m:drivers/char/drm/tdfx_drv.o$: | |
128 | || m:drivers/ide/ide-detect.o$: | |
129 | || m:drivers/ide/pci/idedriver-pci.o$: | |
130 | || m:drivers/media/media.o$: | |
131 | || m:drivers/scsi/sd_mod.o$: | |
132 | || m:drivers/video/video.o$: | |
133 | || m:fs/devpts/devpts.o$: | |
134 | || m:fs/exportfs/exportfs.o$: | |
135 | || m:fs/hugetlbfs/hugetlbfs.o$: | |
136 | || m:fs/msdos/msdos.o$: | |
137 | || m:fs/nls/nls.o$: | |
138 | || m:fs/ramfs/ramfs.o$: | |
139 | || m:fs/romfs/romfs.o$: | |
140 | || m:fs/vfat/vfat.o$: | |
141 | || m:init/mounts.o$: | |
142 | || m:^modules/: | |
143 | || m:net/netlink/netlink.o$: | |
144 | || m:net/sched/sched.o$: | |
145 | || m:/piggy.o$: | |
146 | || m:^scripts/: | |
147 | || m:sound/.*/snd-: | |
148 | || m:^.*/\.tmp_: | |
149 | || m:^\.tmp_: | |
150 | || m:/vmlinux-obj.o$: | |
151 | ) | |
152 | ) { | |
153 | do_nm($basename, $_); | |
154 | } | |
155 | $_ = $basename; # File::Find expects $_ untouched (undocumented) | |
156 | } | |
157 | ||
158 | sub do_nm | |
159 | { | |
160 | my ($basename, $fullname) = @_; | |
161 | my ($source, $type, $name); | |
162 | if (! -e $basename) { | |
163 | printf STDERR "$basename does not exist\n"; | |
164 | return; | |
165 | } | |
166 | if ($fullname !~ /\.o$/) { | |
167 | printf STDERR "$fullname is not an object file\n"; | |
168 | return; | |
169 | } | |
170 | ($source = $fullname) =~ s/\.o$//; | |
171 | if (-e "$objtree$source.c" || -e "$objtree$source.S") { | |
172 | $source = "$objtree$source"; | |
173 | } else { | |
174 | $source = "$srctree$source"; | |
175 | } | |
176 | if (! -e "$source.c" && ! -e "$source.S") { | |
177 | # No obvious source, exclude the object if it is conglomerate | |
178 | if (! open(OBJDUMPDATA, "$objdump $basename|")) { | |
179 | printf STDERR "$objdump $fullname failed $!\n"; | |
180 | return; | |
181 | } | |
182 | my $comment; | |
183 | while (<OBJDUMPDATA>) { | |
184 | chomp(); | |
185 | if (/^In archive/) { | |
186 | # Archives are always conglomerate | |
187 | $comment = "GCC:GCC:"; | |
188 | last; | |
189 | } | |
190 | next if (! /^[ 0-9a-f]{5,} /); | |
191 | $comment .= substr($_, 43); | |
192 | } | |
193 | close(OBJDUMPDATA); | |
194 | if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) { | |
195 | printf STDERR "No source file found for $fullname\n"; | |
196 | } | |
197 | return; | |
198 | } | |
199 | if (! open(NMDATA, "$nm $basename|")) { | |
200 | printf STDERR "$nm $fullname failed $!\n"; | |
201 | return; | |
202 | } | |
203 | my @nmdata; | |
204 | while (<NMDATA>) { | |
205 | chop; | |
206 | ($type, $name) = (split(/ +/, $_, 3))[1..2]; | |
207 | # Expected types | |
208 | # A absolute symbol | |
209 | # B weak external reference to data that has been resolved | |
210 | # C global variable, uninitialised | |
211 | # D global variable, initialised | |
212 | # G global variable, initialised, small data section | |
213 | # R global array, initialised | |
214 | # S global variable, uninitialised, small bss | |
215 | # T global label/procedure | |
216 | # U external reference | |
217 | # W weak external reference to text that has been resolved | |
218 | # a assembler equate | |
219 | # b static variable, uninitialised | |
220 | # d static variable, initialised | |
221 | # g static variable, initialised, small data section | |
222 | # r static array, initialised | |
223 | # s static variable, uninitialised, small bss | |
224 | # t static label/procedures | |
225 | # w weak external reference to text that has not been resolved | |
226 | # ? undefined type, used a lot by modules | |
227 | if ($type !~ /^[ABCDGRSTUWabdgrstw?]$/) { | |
228 | printf STDERR "nm output for $fullname contains unknown type '$_'\n"; | |
229 | } | |
230 | elsif ($name =~ /\./) { | |
231 | # name with '.' is local static | |
232 | } | |
233 | else { | |
234 | $type = 'R' if ($type eq '?'); # binutils replaced ? with R at one point | |
235 | # binutils keeps changing the type for exported symbols, force it to R | |
236 | $type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/); | |
237 | $name =~ s/_R[a-f0-9]{8}$//; # module versions adds this | |
238 | if ($type =~ /[ABCDGRSTW]/ && | |
239 | $name ne 'init_module' && | |
240 | $name ne 'cleanup_module' && | |
241 | $name ne 'Using_Versions' && | |
242 | $name !~ /^Version_[0-9]+$/ && | |
243 | $name !~ /^__parm_/ && | |
244 | $name !~ /^__kstrtab/ && | |
245 | $name !~ /^__ksymtab/ && | |
246 | $name !~ /^__kcrctab_/ && | |
247 | $name !~ /^__exitcall_/ && | |
248 | $name !~ /^__initcall_/ && | |
249 | $name !~ /^__kdb_initcall_/ && | |
250 | $name !~ /^__kdb_exitcall_/ && | |
251 | $name !~ /^__module_/ && | |
252 | $name !~ /^__mod_/ && | |
253 | $name !~ /^__crc_/ && | |
254 | $name ne '__this_module' && | |
255 | $name ne 'kernel_version') { | |
256 | if (!exists($def{$name})) { | |
257 | $def{$name} = []; | |
258 | } | |
259 | push(@{$def{$name}}, $fullname); | |
260 | } | |
261 | push(@nmdata, "$type $name"); | |
262 | if ($name =~ /^__ksymtab_/) { | |
263 | $name = substr($name, 10); | |
264 | if (!exists($ksymtab{$name})) { | |
265 | $ksymtab{$name} = []; | |
266 | } | |
267 | push(@{$ksymtab{$name}}, $fullname); | |
268 | } | |
269 | } | |
270 | } | |
271 | close(NMDATA); | |
272 | if ($#nmdata < 0) { | |
273 | if ( | |
274 | $fullname ne "lib/brlock.o" | |
275 | && $fullname ne "lib/dec_and_lock.o" | |
276 | && $fullname ne "fs/xfs/xfs_macros.o" | |
277 | && $fullname ne "drivers/ide/ide-probe-mini.o" | |
278 | && $fullname ne "usr/initramfs_data.o" | |
279 | && $fullname ne "drivers/acpi/executer/exdump.o" | |
280 | && $fullname ne "drivers/acpi/resources/rsdump.o" | |
281 | && $fullname ne "drivers/acpi/namespace/nsdumpdv.o" | |
282 | && $fullname ne "drivers/acpi/namespace/nsdump.o" | |
283 | && $fullname ne "arch/ia64/sn/kernel/sn2/io.o" | |
284 | && $fullname ne "arch/ia64/kernel/gate-data.o" | |
285 | && $fullname ne "drivers/ieee1394/oui.o" | |
286 | && $fullname ne "security/capability.o" | |
287 | && $fullname ne "sound/core/wrappers.o" | |
288 | && $fullname ne "fs/ntfs/sysctl.o" | |
289 | && $fullname ne "fs/jfs/jfs_debug.o" | |
290 | ) { | |
291 | printf "No nm data for $fullname\n"; | |
292 | } | |
293 | return; | |
294 | } | |
295 | $nmdata{$fullname} = \@nmdata; | |
296 | } | |
297 | ||
298 | sub drop_def | |
299 | { | |
300 | my ($object, $name) = @_; | |
301 | my $nmdata = $nmdata{$object}; | |
302 | my ($i, $j); | |
303 | for ($i = 0; $i <= $#{$nmdata}; ++$i) { | |
304 | if ($name eq (split(' ', $nmdata->[$i], 2))[1]) { | |
305 | splice(@{$nmdata{$object}}, $i, 1); | |
306 | my $def = $def{$name}; | |
307 | for ($j = 0; $j < $#{$def{$name}}; ++$j) { | |
308 | if ($def{$name}[$j] eq $object) { | |
309 | splice(@{$def{$name}}, $j, 1); | |
310 | } | |
311 | } | |
312 | last; | |
313 | } | |
314 | } | |
315 | } | |
316 | ||
317 | sub list_multiply_defined | |
318 | { | |
319 | my ($name, $module); | |
320 | foreach $name (keys(%def)) { | |
321 | if ($#{$def{$name}} > 0) { | |
322 | # Special case for cond_syscall | |
323 | if ($#{$def{$name}} == 1 && $name =~ /^sys_/ && | |
324 | ($def{$name}[0] eq "kernel/sys.o" || | |
325 | $def{$name}[1] eq "kernel/sys.o")) { | |
326 | &drop_def("kernel/sys.o", $name); | |
327 | next; | |
328 | } | |
329 | # Special case for i386 entry code | |
330 | if ($#{$def{$name}} == 1 && $name =~ /^__kernel_/ && | |
331 | $def{$name}[0] eq "arch/i386/kernel/vsyscall-int80.o" && | |
332 | $def{$name}[1] eq "arch/i386/kernel/vsyscall-sysenter.o") { | |
333 | &drop_def("arch/i386/kernel/vsyscall-sysenter.o", $name); | |
334 | next; | |
335 | } | |
336 | printf "$name is multiply defined in :-\n"; | |
337 | foreach $module (@{$def{$name}}) { | |
338 | printf "\t$module\n"; | |
339 | } | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
344 | sub resolve_external_references | |
345 | { | |
346 | my ($object, $type, $name, $i, $j, $kstrtab, $ksymtab, $export); | |
347 | printf "\n"; | |
348 | foreach $object (keys(%nmdata)) { | |
349 | my $nmdata = $nmdata{$object}; | |
350 | for ($i = 0; $i <= $#{$nmdata}; ++$i) { | |
351 | ($type, $name) = split(' ', $nmdata->[$i], 2); | |
352 | if ($type eq "U" || $type eq "w") { | |
353 | if (exists($def{$name}) || exists($ksymtab{$name})) { | |
354 | # add the owning object to the nmdata | |
355 | $nmdata->[$i] = "$type $name $object"; | |
356 | # only count as a reference if it is not EXPORT_... | |
357 | $kstrtab = "R __kstrtab_$name"; | |
358 | $ksymtab = "R __ksymtab_$name"; | |
359 | $export = 0; | |
360 | for ($j = 0; $j <= $#{$nmdata}; ++$j) { | |
361 | if ($nmdata->[$j] eq $kstrtab || | |
362 | $nmdata->[$j] eq $ksymtab) { | |
363 | $export = 1; | |
364 | last; | |
365 | } | |
366 | } | |
367 | if ($export) { | |
368 | $export{$name} = ""; | |
369 | } | |
370 | else { | |
371 | $ref{$name} = "" | |
372 | } | |
373 | } | |
374 | elsif ( $name ne "mod_use_count_" | |
375 | && $name ne "__initramfs_end" | |
376 | && $name ne "__initramfs_start" | |
377 | && $name ne "_einittext" | |
378 | && $name ne "_sinittext" | |
379 | && $name ne "kallsyms_names" | |
380 | && $name ne "kallsyms_num_syms" | |
381 | && $name ne "kallsyms_addresses" | |
382 | && $name ne "__this_module" | |
383 | && $name ne "_etext" | |
384 | && $name ne "_edata" | |
385 | && $name ne "_end" | |
386 | && $name ne "__bss_start" | |
387 | && $name ne "_text" | |
388 | && $name ne "_stext" | |
389 | && $name ne "__gp" | |
390 | && $name ne "ia64_unw_start" | |
391 | && $name ne "ia64_unw_end" | |
392 | && $name ne "__init_begin" | |
393 | && $name ne "__init_end" | |
394 | && $name ne "__bss_stop" | |
395 | && $name ne "__nosave_begin" | |
396 | && $name ne "__nosave_end" | |
397 | && $name ne "pg0" | |
398 | && $name ne "__module_text_address" | |
399 | && $name !~ /^__sched_text_/ | |
400 | && $name !~ /^__start_/ | |
401 | && $name !~ /^__end_/ | |
402 | && $name !~ /^__stop_/ | |
403 | && $name !~ /^__scheduling_functions_.*_here/ | |
404 | && $name !~ /^__.*initcall_/ | |
405 | && $name !~ /^__.*per_cpu_start/ | |
406 | && $name !~ /^__.*per_cpu_end/ | |
407 | && $name !~ /^__alt_instructions/ | |
408 | && $name !~ /^__setup_/ | |
409 | && $name !~ /^jiffies/ | |
410 | && $name !~ /^__mod_timer/ | |
411 | && $name !~ /^__mod_page_state/ | |
412 | && $name !~ /^init_module/ | |
413 | && $name !~ /^cleanup_module/ | |
414 | ) { | |
415 | printf "Cannot resolve "; | |
416 | printf "weak " if ($type eq "w"); | |
417 | printf "reference to $name from $object\n"; | |
418 | } | |
419 | } | |
420 | } | |
421 | } | |
422 | } | |
423 | ||
424 | sub list_extra_externals | |
425 | { | |
426 | my %noref = (); | |
427 | my ($name, @module, $module, $export); | |
428 | foreach $name (keys(%def)) { | |
429 | if (! exists($ref{$name})) { | |
430 | @module = @{$def{$name}}; | |
431 | foreach $module (@module) { | |
432 | if (! exists($noref{$module})) { | |
433 | $noref{$module} = []; | |
434 | } | |
435 | push(@{$noref{$module}}, $name); | |
436 | } | |
437 | } | |
438 | } | |
439 | if (%noref) { | |
440 | printf "\nExternally defined symbols with no external references\n"; | |
441 | foreach $module (sort(keys(%noref))) { | |
442 | printf " $module\n"; | |
443 | foreach (sort(@{$noref{$module}})) { | |
444 | if (exists($export{$_})) { | |
445 | $export = " (export only)"; | |
446 | } | |
447 | else { | |
448 | $export = ""; | |
449 | } | |
450 | printf " $_$export\n"; | |
451 | } | |
452 | } | |
453 | } | |
454 | } |