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Diffstat (limited to 'scripts/namespace.pl')
| -rwxr-xr-x | scripts/namespace.pl | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/scripts/namespace.pl b/scripts/namespace.pl new file mode 100755 index 00000000..a71be6b7 --- /dev/null +++ b/scripts/namespace.pl @@ -0,0 +1,470 @@ +#!/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 + +my %nmexception = ( + 'fs/ext3/bitmap' => 1, + 'fs/ext4/bitmap' => 1, + 'arch/x86/lib/thunk_32' => 1, + 'arch/x86/lib/cmpxchg' => 1, + 'arch/x86/vdso/vdso32/note' => 1, + 'lib/irq_regs' => 1, + 'usr/initramfs_data' => 1, + 'drivers/scsi/aic94xx/aic94xx_dump' => 1, + 'drivers/scsi/libsas/sas_dump' => 1, + 'lib/dec_and_lock' => 1, + 'drivers/ide/ide-probe-mini' => 1, + 'usr/initramfs_data' => 1, + 'drivers/acpi/acpia/exdump' => 1, + 'drivers/acpi/acpia/rsdump' => 1, + 'drivers/acpi/acpia/nsdumpdv' => 1, + 'drivers/acpi/acpia/nsdump' => 1, + 'arch/ia64/sn/kernel/sn2/io' => 1, + 'arch/ia64/kernel/gate-data' => 1, + 'security/capability' => 1, + 'fs/ntfs/sysctl' => 1, + 'fs/jfs/jfs_debug' => 1, +); + +my %nameexception = ( + 'mod_use_count_' => 1, + '__initramfs_end' => 1, + '__initramfs_start' => 1, + '_einittext' => 1, + '_sinittext' => 1, + 'kallsyms_names' => 1, + 'kallsyms_num_syms' => 1, + 'kallsyms_addresses'=> 1, + '__this_module' => 1, + '_etext' => 1, + '_edata' => 1, + '_end' => 1, + '__bss_start' => 1, + '_text' => 1, + '_stext' => 1, + '__gp' => 1, + 'ia64_unw_start' => 1, + 'ia64_unw_end' => 1, + '__init_begin' => 1, + '__init_end' => 1, + '__bss_stop' => 1, + '__nosave_begin' => 1, + '__nosave_end' => 1, + 'pg0' => 1, + 'vdso_enabled' => 1, + '__stack_chk_fail' => 1, + 'VDSO32_PRELINK' => 1, + 'VDSO32_vsyscall' => 1, + 'VDSO32_rt_sigreturn'=>1, + 'VDSO32_sigreturn' => 1, +); + + +&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$: + || m:arch/x86/vdso/: + || m:arch/x86/boot/: + || m:arch/ia64/ia32/ia32.o$: + || 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$: + || m:^tools/: + ) + ) { + do_nm($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 = $basename) =~ s/\.o$//; + if (-e "$source.c" || -e "$source.S") { + $source = "$objtree$File::Find::dir/$source"; + } else { + $source = "$srctree$File::Find::dir/$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(/ +/, $_, 3))[1..2]; + # Expected types + # A absolute symbol + # B weak external reference to data that has been resolved + # C global variable, uninitialised + # D global variable, initialised + # G global variable, initialised, small data section + # R global array, initialised + # S global variable, uninitialised, small bss + # T global label/procedure + # U external reference + # W weak external reference to text that has been resolved + # V similar to W, but the value of the weak symbol becomes zero with no error. + # a assembler equate + # b static variable, uninitialised + # d static variable, initialised + # g static variable, initialised, small data section + # r static array, initialised + # s static variable, uninitialised, small bss + # t static label/procedures + # w weak external reference to text that has not been resolved + # v similar to w + # ? undefined type, used a lot by modules + if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) { + 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 =~ /[ABCDGRSTWV]/ && + $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) { + printf "No nm data for $fullname\n" + unless $nmexception{$fullname}; + 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_/ || $name =~ /^compat_sys_/ || + $name =~ /^sys32_/)) { + if($def{$name}[0] eq "kernel/sys_ni.o" || + $def{$name}[1] eq "kernel/sys_ni.o") { + &drop_def("kernel/sys_ni.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 ( ! $nameexception{$name} + && $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 !~ /^__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"; + } + } + } +} |