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+#!/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
+
+&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$:
+ || m:arch/x86/kernel/vsyscall-syms.o$:
+ || 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$:
+ || m:^scripts/:
+ || m:sound/.*/snd-:
+ || m:^.*/\.tmp_:
+ || m:^\.tmp_:
+ || m:/vmlinux-obj.o$:
+ )
+ ) {
+ 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 = $fullname) =~ s/\.o$//;
+ if (-e "$objtree$source.c" || -e "$objtree$source.S") {
+ $source = "$objtree$source";
+ } else {
+ $source = "$srctree$source";
+ }
+ if (! -e "$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(/ +/, $_, 3))[1..2];
+ # Expected types
+ # A absolute symbol
+ # B weak external reference to data that has been resolved
+ # C global variable, uninitialised
+ # D global variable, initialised
+ # G global variable, initialised, small data section
+ # R global array, initialised
+ # S global variable, uninitialised, small bss
+ # T global label/procedure
+ # U external reference
+ # W weak external reference to text that has been resolved
+ # a assembler equate
+ # b static variable, uninitialised
+ # d static variable, initialised
+ # g static variable, initialised, small data section
+ # r static array, initialised
+ # s static variable, uninitialised, small bss
+ # t static label/procedures
+ # w weak external reference to text that has not been resolved
+ # ? undefined type, used a lot by modules
+ if ($type !~ /^[ABCDGRSTUWabdgrstw?]$/) {
+ 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 =~ /[ABCDGRSTW]/ &&
+ $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) {
+ if (
+ $fullname ne "lib/brlock.o"
+ && $fullname ne "lib/dec_and_lock.o"
+ && $fullname ne "fs/xfs/xfs_macros.o"
+ && $fullname ne "drivers/ide/ide-probe-mini.o"
+ && $fullname ne "usr/initramfs_data.o"
+ && $fullname ne "drivers/acpi/executer/exdump.o"
+ && $fullname ne "drivers/acpi/resources/rsdump.o"
+ && $fullname ne "drivers/acpi/namespace/nsdumpdv.o"
+ && $fullname ne "drivers/acpi/namespace/nsdump.o"
+ && $fullname ne "arch/ia64/sn/kernel/sn2/io.o"
+ && $fullname ne "arch/ia64/kernel/gate-data.o"
+ && $fullname ne "drivers/ieee1394/oui.o"
+ && $fullname ne "security/capability.o"
+ && $fullname ne "sound/core/wrappers.o"
+ && $fullname ne "fs/ntfs/sysctl.o"
+ && $fullname ne "fs/jfs/jfs_debug.o"
+ ) {
+ printf "No nm data for $fullname\n";
+ }
+ 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 && $name =~ /^sys_/ &&
+ ($def{$name}[0] eq "kernel/sys.o" ||
+ $def{$name}[1] eq "kernel/sys.o")) {
+ &drop_def("kernel/sys.o", $name);
+ next;
+ }
+ # Special case for i386 entry code
+ if ($#{$def{$name}} == 1 && $name =~ /^__kernel_/ &&
+ $def{$name}[0] eq "arch/x86/kernel/vsyscall-int80_32.o" &&
+ $def{$name}[1] eq "arch/x86/kernel/vsyscall-sysenter_32.o") {
+ &drop_def("arch/x86/kernel/vsyscall-sysenter_32.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 ( $name ne "mod_use_count_"
+ && $name ne "__initramfs_end"
+ && $name ne "__initramfs_start"
+ && $name ne "_einittext"
+ && $name ne "_sinittext"
+ && $name ne "kallsyms_names"
+ && $name ne "kallsyms_num_syms"
+ && $name ne "kallsyms_addresses"
+ && $name ne "__this_module"
+ && $name ne "_etext"
+ && $name ne "_edata"
+ && $name ne "_end"
+ && $name ne "__bss_start"
+ && $name ne "_text"
+ && $name ne "_stext"
+ && $name ne "__gp"
+ && $name ne "ia64_unw_start"
+ && $name ne "ia64_unw_end"
+ && $name ne "__init_begin"
+ && $name ne "__init_end"
+ && $name ne "__bss_stop"
+ && $name ne "__nosave_begin"
+ && $name ne "__nosave_end"
+ && $name ne "pg0"
+ && $name ne "__module_text_address"
+ && $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 !~ /^jiffies/
+ && $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";
+ }
+ }
+ }
+}
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