Re: [PATCH] Embed __this_module in module itself.

From: Miles Bader (miles@lsi.nec.co.jp)
Date: Mon Jan 06 2003 - 06:03:12 EST


When I try to build modules using 2.5.54, the resulting .ko files lack
the .gnu.linkonce.* sections, which causes the kernel module loader to
fail on them -- those sections _are_ present in the .o files, but the
linker apparently removes them!

Any clues why it's doing this (I tried GNU ld versions 2.13.2.1 and
2.11.92.0.12.3, and both act the same)? Is there something
arch-specific I need to do?

[The .ko file is produce by just doing `ld -r', e.g.:

   v850e-elf-ld -r -o drivers/block/loop.ko drivers/block/loop.o

For instance, for the loop device, here's the output of `readelf -S loop.o':

---------------- begin ----------------
There are 25 section headers, starting at offset 0x1d99c:

Section Headers:
  [Nr] Name Type Addr Off Size ES Flg Lk Inf Al
  [ 0] NULL 00000000 000000 000000 00 0 0 0
  [ 1] .text PROGBITS 00000000 000034 00186c 00 AX 0 0 2
  [ 2] .rela.text RELA 00000000 01ea40 0005c4 0c 23 1 4
  [ 3] .data PROGBITS 00000000 0018a0 0000a4 00 WA 0 0 4
  [ 4] .rela.data RELA 00000000 01f004 000078 0c 23 3 4
  [ 5] .bss NOBITS 00000000 001944 000008 00 WA 0 0 4
  [ 6] .call_table_data PROGBITS 00000000 001944 000000 00 WA 0 0 1
  [ 7] .call_table_text PROGBITS 00000000 001944 000000 00 AX 0 0 1
  [ 8] .stab PROGBITS 00000000 001944 008538 0c 10 0 4
  [ 9] .rela.stab RELA 00000000 01f07c 000b10 0c 23 8 4
  [10] .stabstr STRTAB 00000000 009e7c 013448 00 0 0 1
  [11] .plt NOBITS 00000000 01d2c8 000000 00 AX 0 0 8
  [12] .init.plt NOBITS 00000000 01d2c8 000000 00 AX 0 0 8
  [13] .gnu.linkonce.thi PROGBITS 00000000 01d2c8 0000b0 00 WA 0 0 4
  [14] .rela.gnu.linkonc RELA 00000000 01fb8c 000024 0c 23 d 4
  [15] .rodata PROGBITS 00000000 01d378 0001bf 00 A 0 0 1
  [16] __obsparm PROGBITS 00000000 01d538 000080 00 WA 0 0 4
  [17] __ksymtab PROGBITS 00000000 01d5b8 000080 00 A 0 0 4
  [18] .rela__ksymtab RELA 00000000 01fbb0 000018 0c 23 11 4
  [19] .init.text PROGBITS 00000000 01d638 000220 00 AX 0 0 2
  [20] .rela.init.text RELA 00000000 01fbc8 000138 0c 23 13 4
  [21] .comment PROGBITS 00000000 01d858 00002d 00 0 0 1
  [22] .shstrtab STRTAB 00000000 01d885 000115 00 0 0 1
  [23] .symtab SYMTAB 00000000 01dd84 000710 10 24 34 4
  [24] .strtab STRTAB 00000000 01e494 0005ab 00 0 0 1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings)
  I (info), L (link order), G (group), x (unknown)
  O (extra OS processing required) o (OS specific), p (processor specific)
---------------- end ----------------

and here's the output of `readelf -S loop.ko'

---------------- begin ----------------
There are 23 section headers, starting at offset 0x1d938:

Section Headers:
  [Nr] Name Type Addr Off Size ES Flg Lk Inf Al
  [ 0] NULL 00000000 000000 000000 00 0 0 0
  [ 1] .plt NOBITS 00100000 000038 000000 00 AX 0 0 8
  [ 2] .text PROGBITS 00100000 000038 00191c 00 WAX 0 0 4
  [ 3] .rela.text RELA 00000000 01dcd0 0005e8 0c 21 2 4
  [ 4] .call_table_data PROGBITS 0010191c 001954 000000 00 WA 0 0 1
  [ 5] .call_table_text PROGBITS 0010191c 001954 000000 00 AX 0 0 1
  [ 6] .rodata PROGBITS 0010191c 001954 0001bf 00 A 0 0 1
  [ 7] .data PROGBITS 00101adc 001b14 0000a4 00 WA 0 0 4
  [ 8] .rela.data RELA 00000000 01e2b8 000078 0c 21 7 4
  [ 9] .bss NOBITS 00101b80 001bb8 000008 00 WA 0 0 4
  [10] .stab PROGBITS 00000000 001bb8 008538 0c 12 0 4
  [11] .rela.stab RELA 00000000 01e330 000b10 0c 21 a 4
  [12] .stabstr STRTAB 00000000 00a0f0 013448 00 0 0 1
  [13] .comment PROGBITS 00000000 01d538 00002d 00 0 0 1
  [14] .init.plt NOBITS 00000030 01d568 000000 00 AX 0 0 8
  [15] __obsparm PROGBITS 00000030 01d568 000080 00 WA 0 0 4
  [16] __ksymtab PROGBITS 000000b0 01d5e8 000080 00 A 0 0 4
  [17] .rela__ksymtab RELA 00000000 01ee40 000018 0c 21 10 4
  [18] .init.text PROGBITS 00000130 01d668 000220 00 AX 0 0 2
  [19] .rela.init.text RELA 00000000 01ee58 000138 0c 21 12 4
  [20] .shstrtab STRTAB 00000000 01d888 0000b0 00 0 0 1
  [21] .symtab SYMTAB 00000000 01ef90 000780 10 22 3b 4
  [22] .strtab STRTAB 00000000 01f710 0005ab 00 0 0 1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings)
  I (info), L (link order), G (group), x (unknown)
  O (extra OS processing required) o (OS specific), p (processor specific)
---------------- end ----------------

Thanks,

-Miles

-- 
Somebody has to do something, and it's just incredibly pathetic that it
has to be us.  -- Jerry Garcia
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