linux-toradex.git/scripts/kallsyms.c, branch v4.4.93

Kbuild: kallsyms: drop special handling of pre-3.0 GCC symbols

2015-04-07T11:04:51+00:00

Since we have required at least GCC v3.2 for some time now, we
can drop the special handling of the 'gcc[0-9]_compiled.' label
which is not emitted anymore since GCC v3.0.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Michal Marek

Kbuild: kallsyms: ignore veneers emitted by the ARM linker

2015-04-07T11:04:50+00:00

When linking large kernels on ARM, the linker will insert veneers
(i.e., PLT like stubs) when function symbols are out of reach for
the ordinary relative branch/branch-and-link instructions.

However, due to the fact that the kallsyms region sits in .rodata,
which is between .text and .init.text, additional veneers may be
emitted in the second pass due to the fact that the size of the
kallsyms region itself has pushed the .init.text section further
apart, requiring even more veneers.

So ignore the veneers when generating the symbol table. Veneers
have no corresponding source code, and they will not turn up in
backtraces anyway.

This patch also lightly refactors the symbol_valid() function
to use a local 'sym_name' rather than the obfuscated 'sym + 1'
and 'sym + offset'

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Michal Marek

aarch64: filter $x from kallsyms

2014-10-02T16:01:51+00:00

Similar to ARM, AArch64 is generating $x and $d syms... which isn't
terribly helpful when looking at %pF output and the like. Filter those
out in kallsyms, modpost and when looking at module symbols.

Seems simplest since none of these check EM_ARM anyway, to just add it
to the strchr used, rather than trying to make things overly
complicated.

initcall_debug improves:
dmesg_before.txt: initcall $x+0x0/0x154 [sg] returned 0 after 26331 usecs
dmesg_after.txt: initcall init_sg+0x0/0x154 [sg] returned 0 after 15461 usecs

Signed-off-by: Kyle McMartin 
Acked-by: Rusty Russell 
Signed-off-by: Catalin Marinas

kbuild: trivial - use tabs for code indent where possible

2014-06-10T12:00:53+00:00

Signed-off-by: Masahiro Yamada 
Signed-off-by: Michal Marek

kallsyms: fix percpu vars on x86-64 with relocation.

2014-03-17T04:25:27+00:00

x86-64 has a problem: per-cpu variables are actually represented by
their absolute offsets within the per-cpu area, but the symbols are
not emitted as absolute.  Thus kallsyms naively creates them as offsets
from _text, meaning their values change if the kernel is relocated
(especially noticeable with CONFIG_RANDOMIZE_BASE):

 $ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.nokaslr
 0000000000000000 D __per_cpu_start
 0000000000004000 D gdt_page
 0000000000014280 D __per_cpu_end
 ffffffff810001c8 T _stext
 ffffffff81ee53c0 D __per_cpu_offset
 $ egrep ' (gdt_|_(stext|_per_cpu_))' /root/kallsyms.kaslr1
 000000001f200000 D __per_cpu_start
 000000001f204000 D gdt_page
 000000001f214280 D __per_cpu_end
 ffffffffa02001c8 T _stext
 ffffffffa10e53c0 D __per_cpu_offset

Making them absolute symbols is the Right Thing, but requires fixes to
the relocs tool.  So for the moment, we add a --absolute-percpu option
which makes them absolute from a kallsyms perspective:

 $ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # no KASLR
 0000000000000000 A __per_cpu_start
 000000000000a000 A gdt_page
 0000000000013040 A __per_cpu_end
 ffffffff802001c8 T _stext
 ffffffff8099b180 D __per_cpu_offset
 ffffffff809a3000 D __per_cpu_load
 $ egrep ' (gdt_|_(stext|_per_cpu_))' /proc/kallsyms # With KASLR
 0000000000000000 A __per_cpu_start
 000000000000a000 A gdt_page
 0000000000013040 A __per_cpu_end
 ffffffff89c001c8 T _stext
 ffffffff8a39d180 D __per_cpu_offset
 ffffffff8a3a5000 D __per_cpu_load

Based-on-the-original-screenplay-by: Andy Honig 
Signed-off-by: Rusty Russell 
Acked-by: Kees Cook

kallsyms: generalize address range checking

2014-03-17T04:24:50+00:00

This refactors the address range checks to be generalized instead of
specific to text range checks, in preparation for other range checks.
Also extracts logic for "is the symbol absolute" into a function.

Signed-off-by: Kees Cook 
Signed-off-by: Rusty Russell

revert "kallsyms: fix absolute addresses for kASLR"

2014-03-11T00:26:20+00:00

Revert the recently applied 0f55159d091c ("kallsyms: fix absolute
addresses for kASLR").  Kees said

: This got NAKed, please don't apply -- this patch works for x86 and
: ARM, but may cause problems for others:
:
: https://lkml.org/lkml/2014/2/24/718

It appears that Kees will be fixing all this up for 3.15.

Cc: Andy Honig 
Cc: Kees Cook 
Cc: Michal Marek 
Cc: Rusty Russell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kallsyms: fix absolute addresses for kASLR

2014-03-04T15:55:48+00:00

Currently symbols that are absolute addresses are incorrectly displayed
in /proc/kallsyms if the kernel is loaded with kASLR.

The problem was that the scripts/kallsyms.c file which generates the
array of symbol names and addresses uses an relocatable value for all
symbols, even absolute symbols.  This patch fixes that.

Several kallsyms output in different boot states for comparison:

  $ egrep '_(stext|_per_cpu_(start|end))' /root/kallsyms.nokaslr
  0000000000000000 D __per_cpu_start
  0000000000014280 D __per_cpu_end
  ffffffff810001c8 T _stext
  $ egrep '_(stext|_per_cpu_(start|end))' /root/kallsyms.kaslr1
  000000001f200000 D __per_cpu_start
  000000001f214280 D __per_cpu_end
  ffffffffa02001c8 T _stext
  $ egrep '_(stext|_per_cpu_(start|end))' /root/kallsyms.kaslr2
  000000000d400000 D __per_cpu_start
  000000000d414280 D __per_cpu_end
  ffffffff8e4001c8 T _stext
  $ egrep '_(stext|_per_cpu_(start|end))' /root/kallsyms.kaslr-fixed
  0000000000000000 D __per_cpu_start
  0000000000014280 D __per_cpu_end
  ffffffffadc001c8 T _stext

Signed-off-by: Andy Honig 
Signed-off-by: Kees Cook 
Cc: Michal Marek 
Cc: Rusty Russell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2013-11-15T22:06:38+00:00

Pull kbuild changes from Michal Marek:
 - LTO fixes, but the kallsyms part had to be reverted
 - Pass -Werror=implicit-int and -Werror=strict-prototypes to the
   compiler by default
 - snprintf fix in modpost
 - remove GREP_OPTIONS from the environment to be immune against exotic
   grep option settings

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kallsyms: Revert back to 128 max symbol length
  Kbuild: Ignore GREP_OPTIONS env variable
  scripts: kallsyms: Use %zu to print 'size_t'
  scripts/bloat-o-meter: use .startswith rather than fragile slicing
  scripts/bloat-o-meter: ignore changes in the size of linux_banner
  kbuild: replace unbounded sprintf call in modpost
  kbuild, bloat-o-meter: fix static detection
  Kbuild: Handle longer symbols in kallsyms.c
  kbuild: Increase kallsyms max symbol length
  Makefile: enable -Werror=implicit-int and -Werror=strict-prototypes by default

kallsyms: Revert back to 128 max symbol length

2013-11-13T14:58:19+00:00

This reverts commits
f3462aa (Kbuild: Handle longer symbols in kallsyms.c) and
eea0e9c (kbuild: Increase kallsyms max symbol length)
except for the added overflow check. The reason is a regression caused
by increasing the buffer:
http://marc.info/?l=linux-kernel&m=138387700415675.

Reported-by: Fengguang Wu 
Cc: Andi Kleen 
Cc: Joe Mario 
Signed-off-by: Michal Marek