470 lines
13 KiB
Prolog
470 lines
13 KiB
Prolog
#!/usr/bin/perl -w
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#
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# namespace.pl. Mon Aug 30 2004
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#
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# Perform a name space analysis on the linux kernel.
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#
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# Copyright Keith Owens <kaos@ocs.com.au>. GPL.
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#
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# Invoke by changing directory to the top of the kernel object
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# tree then namespace.pl, no parameters.
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#
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# Tuned for 2.1.x kernels with the new module handling, it will
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# work with 2.0 kernels as well.
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#
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# Last change 2.6.9-rc1, adding support for separate source and object
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# trees.
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#
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# The source must be compiled/assembled first, the object files
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# are the primary input to this script. Incomplete or missing
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# objects will result in a flawed analysis. Compile both vmlinux
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# and modules.
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#
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# Even with complete objects, treat the result of the analysis
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# with caution. Some external references are only used by
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# certain architectures, others with certain combinations of
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# configuration parameters. Ideally the source should include
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# something like
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#
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# #ifndef CONFIG_...
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# static
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# #endif
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# symbol_definition;
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#
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# so the symbols are defined as static unless a particular
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# CONFIG_... requires it to be external.
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#
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# A symbol that is suffixed with '(export only)' has these properties
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#
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# * It is global.
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# * It is marked EXPORT_SYMBOL or EXPORT_SYMBOL_GPL, either in the same
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# source file or a different source file.
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# * Given the current .config, nothing uses the symbol.
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#
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# The symbol is a candidate for conversion to static, plus removal of the
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# export. But be careful that a different .config might use the symbol.
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#
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#
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# Name space analysis and cleanup is an iterative process. You cannot
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# expect to find all the problems in a single pass.
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#
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# * Identify possibly unnecessary global declarations, verify that they
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# really are unnecessary and change them to static.
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# * Compile and fix up gcc warnings about static, removing dead symbols
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# as necessary.
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# * make clean and rebuild with different configs (especially
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# CONFIG_MODULES=n) to see which symbols are being defined when the
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# config does not require them. These symbols bloat the kernel object
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# for no good reason, which is frustrating for embedded systems.
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# * Wrap config sensitive symbols in #ifdef CONFIG_foo, as long as the
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# code does not get too ugly.
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# * Repeat the name space analysis until you can live with with the
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# result.
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#
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require 5; # at least perl 5
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use strict;
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use File::Find;
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my $nm = ($ENV{'NM'} || "nm") . " -p";
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my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment";
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my $srctree = "";
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my $objtree = "";
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$srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
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$objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));
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if ($#ARGV != -1) {
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print STDERR "usage: $0 takes no parameters\n";
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die("giving up\n");
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}
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my %nmdata = (); # nm data for each object
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my %def = (); # all definitions for each name
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my %ksymtab = (); # names that appear in __ksymtab_
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my %ref = (); # $ref{$name} exists if there is a true external reference to $name
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my %export = (); # $export{$name} exists if there is an EXPORT_... of $name
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my %nmexception = (
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'fs/ext3/bitmap' => 1,
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'fs/ext4/bitmap' => 1,
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'arch/x86/lib/thunk_32' => 1,
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'arch/x86/lib/cmpxchg' => 1,
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'arch/x86/vdso/vdso32/note' => 1,
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'lib/irq_regs' => 1,
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'usr/initramfs_data' => 1,
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'drivers/scsi/aic94xx/aic94xx_dump' => 1,
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'drivers/scsi/libsas/sas_dump' => 1,
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'lib/dec_and_lock' => 1,
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'drivers/ide/ide-probe-mini' => 1,
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'usr/initramfs_data' => 1,
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'drivers/acpi/acpia/exdump' => 1,
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'drivers/acpi/acpia/rsdump' => 1,
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'drivers/acpi/acpia/nsdumpdv' => 1,
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'drivers/acpi/acpia/nsdump' => 1,
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'arch/ia64/sn/kernel/sn2/io' => 1,
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'arch/ia64/kernel/gate-data' => 1,
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'security/capability' => 1,
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'fs/ntfs/sysctl' => 1,
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'fs/jfs/jfs_debug' => 1,
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);
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my %nameexception = (
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'mod_use_count_' => 1,
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'__initramfs_end' => 1,
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'__initramfs_start' => 1,
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'_einittext' => 1,
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'_sinittext' => 1,
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'kallsyms_names' => 1,
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'kallsyms_num_syms' => 1,
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'kallsyms_addresses'=> 1,
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'__this_module' => 1,
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'_etext' => 1,
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'_edata' => 1,
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'_end' => 1,
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'__bss_start' => 1,
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'_text' => 1,
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'_stext' => 1,
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'__gp' => 1,
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'ia64_unw_start' => 1,
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'ia64_unw_end' => 1,
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'__init_begin' => 1,
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'__init_end' => 1,
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'__bss_stop' => 1,
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'__nosave_begin' => 1,
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'__nosave_end' => 1,
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'pg0' => 1,
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'vdso_enabled' => 1,
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'__stack_chk_fail' => 1,
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'VDSO32_PRELINK' => 1,
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'VDSO32_vsyscall' => 1,
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'VDSO32_rt_sigreturn'=>1,
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'VDSO32_sigreturn' => 1,
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);
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&find(\&linux_objects, '.'); # find the objects and do_nm on them
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&list_multiply_defined();
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&resolve_external_references();
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&list_extra_externals();
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exit(0);
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sub linux_objects
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{
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# Select objects, ignoring objects which are only created by
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# merging other objects. Also ignore all of modules, scripts
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# and compressed. Most conglomerate objects are handled by do_nm,
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# this list only contains the special cases. These include objects
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# that are linked from just one other object and objects for which
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# there is really no permanent source file.
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my $basename = $_;
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$_ = $File::Find::name;
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s:^\./::;
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if (/.*\.o$/ &&
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! (
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m:/built-in.o$:
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|| m:arch/x86/vdso/:
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|| m:arch/x86/boot/:
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|| m:arch/ia64/ia32/ia32.o$:
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|| m:arch/ia64/kernel/gate-syms.o$:
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|| m:arch/ia64/lib/__divdi3.o$:
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|| m:arch/ia64/lib/__divsi3.o$:
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|| m:arch/ia64/lib/__moddi3.o$:
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|| m:arch/ia64/lib/__modsi3.o$:
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|| m:arch/ia64/lib/__udivdi3.o$:
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|| m:arch/ia64/lib/__udivsi3.o$:
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|| m:arch/ia64/lib/__umoddi3.o$:
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|| m:arch/ia64/lib/__umodsi3.o$:
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|| m:arch/ia64/scripts/check_gas_for_hint.o$:
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|| m:arch/ia64/sn/kernel/xp.o$:
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|| m:boot/bbootsect.o$:
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|| m:boot/bsetup.o$:
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|| m:/bootsect.o$:
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|| m:/boot/setup.o$:
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|| m:/compressed/:
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|| m:drivers/cdrom/driver.o$:
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|| m:drivers/char/drm/tdfx_drv.o$:
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|| m:drivers/ide/ide-detect.o$:
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|| m:drivers/ide/pci/idedriver-pci.o$:
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|| m:drivers/media/media.o$:
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|| m:drivers/scsi/sd_mod.o$:
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|| m:drivers/video/video.o$:
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|| m:fs/devpts/devpts.o$:
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|| m:fs/exportfs/exportfs.o$:
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|| m:fs/hugetlbfs/hugetlbfs.o$:
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|| m:fs/msdos/msdos.o$:
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|| m:fs/nls/nls.o$:
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|| m:fs/ramfs/ramfs.o$:
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|| m:fs/romfs/romfs.o$:
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|| m:fs/vfat/vfat.o$:
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|| m:init/mounts.o$:
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|| m:^modules/:
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|| m:net/netlink/netlink.o$:
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|| m:net/sched/sched.o$:
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|| m:/piggy.o$:
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|| m:^scripts/:
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|| m:sound/.*/snd-:
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|| m:^.*/\.tmp_:
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|| m:^\.tmp_:
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|| m:/vmlinux-obj.o$:
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|| m:^tools/:
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)
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) {
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do_nm($basename, $_);
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}
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$_ = $basename; # File::Find expects $_ untouched (undocumented)
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}
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sub do_nm
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{
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my ($basename, $fullname) = @_;
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my ($source, $type, $name);
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if (! -e $basename) {
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printf STDERR "$basename does not exist\n";
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return;
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}
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if ($fullname !~ /\.o$/) {
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printf STDERR "$fullname is not an object file\n";
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return;
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}
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($source = $basename) =~ s/\.o$//;
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if (-e "$source.c" || -e "$source.S") {
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$source = "$objtree$File::Find::dir/$source";
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} else {
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$source = "$srctree$File::Find::dir/$source";
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}
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if (! -e "$source.c" && ! -e "$source.S") {
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# No obvious source, exclude the object if it is conglomerate
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open(my $objdumpdata, "$objdump $basename|")
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or die "$objdump $fullname failed $!\n";
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my $comment;
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while (<$objdumpdata>) {
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chomp();
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if (/^In archive/) {
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# Archives are always conglomerate
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$comment = "GCC:GCC:";
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last;
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}
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next if (! /^[ 0-9a-f]{5,} /);
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$comment .= substr($_, 43);
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}
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close($objdumpdata);
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if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) {
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printf STDERR "No source file found for $fullname\n";
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}
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return;
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}
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open (my $nmdata, "$nm $basename|")
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or die "$nm $fullname failed $!\n";
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my @nmdata;
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while (<$nmdata>) {
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chop;
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($type, $name) = (split(/ +/, $_, 3))[1..2];
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# Expected types
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# A absolute symbol
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# B weak external reference to data that has been resolved
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# C global variable, uninitialised
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# D global variable, initialised
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# G global variable, initialised, small data section
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# R global array, initialised
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# S global variable, uninitialised, small bss
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# T global label/procedure
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# U external reference
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# W weak external reference to text that has been resolved
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# V similar to W, but the value of the weak symbol becomes zero with no error.
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# a assembler equate
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# b static variable, uninitialised
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# d static variable, initialised
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# g static variable, initialised, small data section
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# r static array, initialised
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# s static variable, uninitialised, small bss
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# t static label/procedures
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# w weak external reference to text that has not been resolved
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# v similar to w
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# ? undefined type, used a lot by modules
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if ($type !~ /^[ABCDGRSTUWVabdgrstwv?]$/) {
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printf STDERR "nm output for $fullname contains unknown type '$_'\n";
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}
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elsif ($name =~ /\./) {
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# name with '.' is local static
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}
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else {
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$type = 'R' if ($type eq '?'); # binutils replaced ? with R at one point
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# binutils keeps changing the type for exported symbols, force it to R
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$type = 'R' if ($name =~ /^__ksymtab/ || $name =~ /^__kstrtab/);
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$name =~ s/_R[a-f0-9]{8}$//; # module versions adds this
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if ($type =~ /[ABCDGRSTWV]/ &&
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$name ne 'init_module' &&
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$name ne 'cleanup_module' &&
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$name ne 'Using_Versions' &&
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$name !~ /^Version_[0-9]+$/ &&
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$name !~ /^__parm_/ &&
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$name !~ /^__kstrtab/ &&
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$name !~ /^__ksymtab/ &&
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$name !~ /^__kcrctab_/ &&
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$name !~ /^__exitcall_/ &&
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$name !~ /^__initcall_/ &&
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$name !~ /^__kdb_initcall_/ &&
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$name !~ /^__kdb_exitcall_/ &&
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$name !~ /^__module_/ &&
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$name !~ /^__mod_/ &&
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$name !~ /^__crc_/ &&
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$name ne '__this_module' &&
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$name ne 'kernel_version') {
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if (!exists($def{$name})) {
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$def{$name} = [];
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}
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push(@{$def{$name}}, $fullname);
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}
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push(@nmdata, "$type $name");
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if ($name =~ /^__ksymtab_/) {
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$name = substr($name, 10);
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if (!exists($ksymtab{$name})) {
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$ksymtab{$name} = [];
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}
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push(@{$ksymtab{$name}}, $fullname);
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}
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}
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}
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close($nmdata);
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if ($#nmdata < 0) {
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printf "No nm data for $fullname\n"
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unless $nmexception{$fullname};
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return;
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}
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$nmdata{$fullname} = \@nmdata;
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}
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sub drop_def
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{
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my ($object, $name) = @_;
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my $nmdata = $nmdata{$object};
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my ($i, $j);
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for ($i = 0; $i <= $#{$nmdata}; ++$i) {
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if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {
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splice(@{$nmdata{$object}}, $i, 1);
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my $def = $def{$name};
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for ($j = 0; $j < $#{$def{$name}}; ++$j) {
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if ($def{$name}[$j] eq $object) {
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splice(@{$def{$name}}, $j, 1);
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}
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}
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last;
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}
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}
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}
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sub list_multiply_defined
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{
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foreach my $name (keys(%def)) {
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if ($#{$def{$name}} > 0) {
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# Special case for cond_syscall
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if ($#{$def{$name}} == 1 &&
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($name =~ /^sys_/ || $name =~ /^compat_sys_/ ||
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$name =~ /^sys32_/)) {
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if($def{$name}[0] eq "kernel/sys_ni.o" ||
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$def{$name}[1] eq "kernel/sys_ni.o") {
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&drop_def("kernel/sys_ni.o", $name);
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next;
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}
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}
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printf "$name is multiply defined in :-\n";
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foreach my $module (@{$def{$name}}) {
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printf "\t$module\n";
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}
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}
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}
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}
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sub resolve_external_references
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{
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my ($kstrtab, $ksymtab, $export);
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printf "\n";
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foreach my $object (keys(%nmdata)) {
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my $nmdata = $nmdata{$object};
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for (my $i = 0; $i <= $#{$nmdata}; ++$i) {
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my ($type, $name) = split(' ', $nmdata->[$i], 2);
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if ($type eq "U" || $type eq "w") {
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if (exists($def{$name}) || exists($ksymtab{$name})) {
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# add the owning object to the nmdata
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$nmdata->[$i] = "$type $name $object";
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# only count as a reference if it is not EXPORT_...
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$kstrtab = "R __kstrtab_$name";
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$ksymtab = "R __ksymtab_$name";
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$export = 0;
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for (my $j = 0; $j <= $#{$nmdata}; ++$j) {
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if ($nmdata->[$j] eq $kstrtab ||
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$nmdata->[$j] eq $ksymtab) {
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$export = 1;
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last;
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}
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}
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if ($export) {
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$export{$name} = "";
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}
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else {
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$ref{$name} = ""
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}
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}
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elsif ( ! $nameexception{$name}
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&& $name !~ /^__sched_text_/
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&& $name !~ /^__start_/
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&& $name !~ /^__end_/
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&& $name !~ /^__stop_/
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&& $name !~ /^__scheduling_functions_.*_here/
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&& $name !~ /^__.*initcall_/
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&& $name !~ /^__.*per_cpu_start/
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&& $name !~ /^__.*per_cpu_end/
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&& $name !~ /^__alt_instructions/
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&& $name !~ /^__setup_/
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&& $name !~ /^__mod_timer/
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&& $name !~ /^__mod_page_state/
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&& $name !~ /^init_module/
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&& $name !~ /^cleanup_module/
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) {
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printf "Cannot resolve ";
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printf "weak " if ($type eq "w");
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printf "reference to $name from $object\n";
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}
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}
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}
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}
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}
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sub list_extra_externals
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{
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my %noref = ();
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foreach my $name (keys(%def)) {
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if (! exists($ref{$name})) {
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my @module = @{$def{$name}};
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foreach my $module (@module) {
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if (! exists($noref{$module})) {
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$noref{$module} = [];
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}
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push(@{$noref{$module}}, $name);
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}
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}
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}
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if (%noref) {
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printf "\nExternally defined symbols with no external references\n";
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foreach my $module (sort(keys(%noref))) {
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printf " $module\n";
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foreach (sort(@{$noref{$module}})) {
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my $export;
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if (exists($export{$_})) {
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$export = " (export only)";
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} else {
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$export = "";
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}
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printf " $_$export\n";
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}
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}
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}
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}
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