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  1. 28 12月, 2010 1 次提交
    • O
      modpost: Fix address calculation in reloc_location() · 731ece41
      由 Olof Johansson 提交于 
      This patch fixes a segfault in modpost that is observed when the gold
linker is used to link the input objects.

The problem is that reloc_location (modpost.c) is computing the
address of the relocation target incorrectly. Here, elf->hdr points
to the beginning of the ELF file in memory, sechdr points to the
relocation section header, section is the index of the section
being relocated, and sechdrs[section].sh_offset would be the offset
of that section, relative to the beginning of the ELF file. Adding
elf->hdr + sechdrs[section].sh_offset gives you the address of the
beginning of the section, and adding r->r_offset to that gives you the
address of the location to be relocated. You do not need to subtract
sechdrs[section].sh_addr from that -- the result of this is an address
outside the file, and causes the segfault when addend_386_rel tries to
dereference it.

This bug is not observed when GNU ld is used to link the inputs. The
object file ubuntu/omnibook/omnibook.o is the result of an ld -r of
several other files.  When GNU ld does an ld -r, it sets the vaddr
field for each section to 0, but gold lays out the section addresses
sequentially instead:

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 004794 00  AX  0   0  4
 [ 2] .data             PROGBITS        0000b9d0 0047c8 0009c0 00  WA  0   0  4
 [ 3] .bss              NOBITS          000162f8 005188 00013c 00  WA  0   0  4
 [ 4] .rodata.str1.1    PROGBITS        00004f2d 0052c4 001b1a 01 AMS  0   0  1
 [ 5] .init.text        PROGBITS        00004794 006dde 0005fa 00  AX  0   0  1
 [ 6] .exit.text        PROGBITS        00004d8e 0073d8 00018a 00  AX  0   0  1
  ...

So the bug in the tool remained undiscovered because the section's vaddr
always happened to be 0.
Signed-off-by: NRaymes Khoury <raymes@google.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NMichal Marek <mmarek@suse.cz>
      731ece41
  3. 23 12月, 2010 1 次提交
  5. 20 12月, 2010 1 次提交
  7. 17 12月, 2010 1 次提交
  9. 15 12月, 2010 1 次提交
  11. 14 12月, 2010 1 次提交
  13. 25 11月, 2010 1 次提交
  15. 12 11月, 2010 1 次提交
    • E
      fixdep: use hash table instead of a single array · 8af27e1d
      由 Eric Dumazet 提交于 
      I noticed fixdep uses ~2% of cpu time in kernel build, in function
use_config()

fixdep spends a lot of cpu cycles in linear searches in its internal
string array. With about 400 stored strings per dep file, this begins to
be noticeable.

Convert fixdep to use a hash table.

kbuild results on my x86_64 allmodconfig

Before patch :

real	10m30.414s
user	61m51.456s
sys	8m28.200s

real	10m12.334s
user	61m50.236s
sys	8m30.448s

real	10m42.947s
user	61m50.028s
sys	8m32.380s

After:

real	10m8.180s
user	61m22.506s
sys	8m32.384s

real	10m35.039s
user	61m21.654s
sys	8m32.212s

real	10m14.487s
user	61m23.498s
sys	8m32.312s
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>
      8af27e1d
  17. 30 10月, 2010 3 次提交
    • T
      semaphore: Remove mutex emulation · 4882720b
      由 Thomas Gleixner 提交于 
      Semaphores used as mutexes have been deprecated for years. Now that
all users are either converted to real semaphores or to mutexes remove
the cruft.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
LKML-Reference: <20100907125057.562399240@linutronix.de>
      4882720b
    • W
      ftrace/MIPS: Add module support for C version of recordmcount · 412910cd
      由 Wu Zhangjin 提交于 
      Since MIPS modules' address space differs from the core kernel space, to access
the _mcount in the core kernel, the kernel functions in modules must use long
call (-mlong-calls): load the _mcount address into one register and jump to the
address stored by the register:

 c:  3c030000        lui     v1,0x0  <-------->  b label
           c: R_MIPS_HI16  _mcount
           c: R_MIPS_NONE  *ABS*
           c: R_MIPS_NONE  *ABS*
10:  64630000        daddiu  v1,v1,0
          10: R_MIPS_LO16 _mcount
          10: R_MIPS_NONE *ABS*
          10: R_MIPS_NONE *ABS*
14:	03e0082d 	move	at,ra
18:	0060f809 	jalr	v1
label:

In the old Perl version of recordmcount, we only need to record the position of
the 1st R_MIPS_HI16 type of _mcount, and later, in ftrace_make_nop(), replace
the instruction in this position by a "b label" and in ftrace_make_call(),
replace it back.

But, the default C version of recordmcount records all of the _mcount symbols,
so, we must filter the 2nd _mcount like the Perl version of recordmcount does.

The C version of recordmcount copes with the symbols before they are linked, So
It doesn't know the type of the symbols and therefore can not filter the
symbols as the Perl version of recordmcount does. But as we can see above, the
2nd _mcount symbols of the long call alawys follows the 1st _mcount symbol of
the same long call, which means the offset from the 1st to the 2nd is fixed, it
is 0x10-0xc = 4 here, 4 is the length of the 1st load instruciton, for MIPS has
fixed length of instructions, this offset is always 4.

And as we know, the _mcount is inserted into the entry of every kernel
function, the offset between the other _mcount's is expected to be always
bigger than 4. So, to filter the 2ns _mcount symbol of the long call, we can
simply check the offset between two _mcount symbols, If it is 4, then, filter
the 2nd _mcount symbol.

To avoid touching too much code, an 'empty' function fn_is_fake_mcount() is
added for all of the archs, and the specific archs can override it via chaning
the function pointer: is_fake_mcount in do_file() with the e_machine. e.g. This
patch adds MIPS_is_fake_mcount() to override the default fn_is_fake_mcount()
pointed by is_fake_mcount.

This fn_is_fake_mcount() checks if the _mcount symbol is fake, e.g. the 2nd
_mcount symbol of the long call is fake, for there are 2 _mcount symbols mapped
to one real mcount call, so, one of them is fake and must be filtered.

This fn_is_fake_mcount() is called in sift_rel_mcount() after finding the
_mcount symbols and before adding the _mcount symbol into mrelp, so, it can
prevent the fake mcount symbol going into the last __mcount_loc table.
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <b866f0138224340a132d31861fa3f9300dee30ac.1288176026.git.wuzhangjin@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      412910cd
    • J
      ftrace/MIPS: Add MIPS64 support for C version of recordmcount · a2d49358
      由 John Reiser 提交于 
      MIPS64 has 'weird' Elf64_Rel.r_info[1,2], which must be used instead of
the generic Elf64_Rel.r_info, otherwise, the C version of recordmcount
will not work for "segmentation fault".

Usage of "union mips_r_info" and the functions MIPS64_r_sym() and
MIPS64_r_info() written by Maciej W. Rozycki <macro@linux-mips.org>

----
[1] http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
[2] arch/mips/include/asm/module.h
Tested-by: NWu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: NJohn Reiser <jreiser@BitWagon.com>
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
LKML-Reference: <AANLkTinwXjLAYACUfhLYaocHD_vBbiErLN3NjwN8JqSy@mail.gmail.com>
LKML-Reference: <910dc2d5ae1ed042df4f96815fe4a433078d1c2a.1288176026.git.wuzhangjin@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      a2d49358
  19. 29 10月, 2010 6 次提交
  21. 28 10月, 2010 11 次提交
  23. 27 10月, 2010 12 次提交