Commit Graph

46 Commits

Author SHA1 Message Date
Ard Biesheuvel 56067812d5 kbuild: modversions: add infrastructure for emitting relative CRCs
This add the kbuild infrastructure that will allow architectures to emit
vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
where the actual value is stored. This works around problems with CRCs
being mistaken for relocatable symbols on kernels that self relocate at
runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)

For the kbuild side of things, this comes down to the following:

 - introducing a Kconfig symbol MODULE_REL_CRCS

 - adding a -R switch to genksyms to instruct it to emit the CRC symbols
   as references into the .rodata section

 - making modpost distinguish such references from absolute CRC symbols
   by the section index (SHN_ABS)

 - making kallsyms disregard non-absolute symbols with a __crc_ prefix

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 08:28:25 -08:00
Ard Biesheuvel 0f66784ae2 scripts/kallsyms: remove last remnants of --page-offset option
The implementation of the --page-offset kallsyms command line option has
been removed, so remove it from the usage string as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-12-11 12:46:15 +01:00
Ard Biesheuvel 2d95863999 ARM: 8553/1: kallsyms: remove --page-offset command line option
The --page-offset command line option was only used for ARM, to filter
symbol addresses below CONFIG_PAGE_OFFSET. This is no longer needed, so
remove the functionality altogether.

Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2016-04-07 21:57:16 +01:00
Ard Biesheuvel b9b74be163 ARM: 8555/1: kallsyms: ignore ARM mode switching veneers
On ARM, the linker may emit veneers to deal with relative branch
instructions that appear too far away from their targets. Since the
second kallsyms pass results in an increase of the kernel size, it may
result in additional veneers to be emitted, potentially affecting the
output of kallsyms itself if these symbols are visible to it, and for
that reason, symbols whose names end in '_veneer' are ignored explicitly.

However, when building Thumb2 kernels, such veneers are named differently
if they also incur a mode switch, and since they are not filtered by
kallsyms, they may cause the build to fail. So filter symbols whose names
end in '_from_arm' or '_from_thumb' as well.

Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2016-04-07 21:57:15 +01:00
Ard Biesheuvel 2213e9a66b kallsyms: add support for relative offsets in kallsyms address table
Similar to how relative extables are implemented, it is possible to emit
the kallsyms table in such a way that it contains offsets relative to
some anchor point in the kernel image rather than absolute addresses.

On 64-bit architectures, it cuts the size of the kallsyms address table
in half, since offsets between kernel symbols can typically be expressed
in 32 bits.  This saves several hundreds of kilobytes of permanent
.rodata on average.  In addition, the kallsyms address table is no
longer subject to dynamic relocation when CONFIG_RELOCATABLE is in
effect, so the relocation work done after decompression now doesn't have
to do relocation updates for all these values.  This saves up to 24
bytes (i.e., the size of a ELF64 RELA relocation table entry) per value,
which easily adds up to a couple of megabytes of uncompressed __init
data on ppc64 or arm64.  Even if these relocation entries typically
compress well, the combined size reduction of 2.8 MB uncompressed for a
ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500
KB space saving in the compressed image.

Since it is useful for some architectures (like x86) to retain the
ability to emit absolute values as well, this patch also adds support
for capturing both absolute and relative values when
KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu
addresses as positive 32-bit values, and addresses relative to the
lowest encountered relative symbol as negative values, which are
subtracted from the runtime address of this base symbol to produce the
actual address.

Support for the above is enabled by default for all architectures except
IA-64 and Tile-GX, whose symbols are too far apart to capture in this
manner.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15 16:55:16 -07:00
Ard Biesheuvel 8c996940b3 kallsyms: don't overload absolute symbol type for percpu symbols
Commit c6bda7c988 ("kallsyms: fix percpu vars on x86-64 with
relocation") overloaded the 'A' (absolute) symbol type to signify that a
symbol is not subject to dynamic relocation.  However, the original A
type does not imply that at all, and depending on the version of the
toolchain, many A type symbols are emitted that are in fact relative to
the kernel text, i.e., if the kernel is relocated at runtime, these
symbols should be updated as well.

For instance, on sparc32, the following symbols are emitted as absolute
(kindly provided by Guenter Roeck):

  f035a420 A _etext
  f03d9000 A _sdata
  f03de8c4 A jiffies
  f03f8860 A _edata
  f03fc000 A __init_begin
  f041bdc8 A __init_text_end
  f0423000 A __bss_start
  f0423000 A __init_end
  f044457d A __bss_stop
  f044457d A _end

On x86_64, similar behavior can be observed:

  ffffffff81a00000 A __end_rodata_hpage_align
  ffffffff81b19000 A __vvar_page
  ffffffff81d3d000 A _end

Even if only a couple of them pass the symbol range check that results
in them to be taken into account for the final kallsyms symbol table, it
is obvious that 'A' does not mean the symbol does not need to be updated
at relocation time, and overloading its meaning to signify that is
perhaps not a good idea.

So instead, add a new percpu_absolute member to struct sym_entry, and
when --absolute-percpu is in effect, use it to record symbols whose
addresses should be emitted as final values rather than values that
still require relocation at runtime.  That way, we can drop the check
against the 'A' type.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Marek <mmarek@suse.cz>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15 16:55:16 -07:00
Ard Biesheuvel 41b585b2ed Kbuild: kallsyms: drop special handling of pre-3.0 GCC symbols
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 <ard.biesheuvel@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-04-07 13:04:51 +02:00
Ard Biesheuvel bd8b22d288 Kbuild: kallsyms: ignore veneers emitted by the ARM linker
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 <ard.biesheuvel@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-04-07 13:04:50 +02:00
Kyle McMartin 6c34f1f542 aarch64: filter $x from kallsyms
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 <kyle@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-10-02 17:01:51 +01:00
Masahiro Yamada bb66fc6719 kbuild: trivial - use tabs for code indent where possible
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-06-10 14:00:53 +02:00
Rusty Russell c6bda7c988 kallsyms: fix percpu vars on x86-64 with relocation.
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 <ahonig@google.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Kees Cook <keescook@chromium.org>
2014-03-17 14:55:27 +10:30
Kees Cook 78eb71594b kallsyms: generalize address range checking
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 <keescook@chromium.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-17 14:54:50 +10:30
Andrew Morton 2930ffc759 revert "kallsyms: fix absolute addresses for kASLR"
Revert the recently applied 0f55159d09 ("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 <ahonig@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-10 17:26:20 -07:00
Andy Honig 0f55159d09 kallsyms: fix absolute addresses for kASLR
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 <ahonig@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-04 07:55:48 -08:00
Linus Torvalds 762fb1ddd5 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
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
2013-11-15 14:06:38 -08:00
Michal Marek 480f439c3d kallsyms: Revert back to 128 max symbol length
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 <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Joe Mario <jmario@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2013-11-13 15:58:19 +01:00
Fabio Estevam 6f62259b1a scripts: kallsyms: Use %zu to print 'size_t'
Commit f3462aa95 (Kbuild: Handle longer symbols in kallsyms.c) introduced the
following warning on ARM:

scripts/kallsyms.c:121:4: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t' [-Wformat]

Use %zu to print 'size_t'.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2013-11-08 10:05:20 +01:00
Andi Kleen f3462aa952 Kbuild: Handle longer symbols in kallsyms.c
Also warn for too long symbols

v2: Add missing newline. Use 255 max (Joe Perches)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2013-11-06 22:25:49 +01:00
Ming Lei f6537f2f0e scripts/kallsyms: filter symbols not in kernel address space
This patch uses CONFIG_PAGE_OFFSET to filter symbols which
are not in kernel address space because these symbols are
generally for generating code purpose and can't be run at
kernel mode, so we needn't keep them in /proc/kallsyms.

For example, on ARM there are some symbols which may be
linked in relocatable code section, then perf can't parse
symbols any more from /proc/kallsyms, this patch fixes the
problem (introduced b9b32bf70f)

Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org
2013-11-02 09:13:02 +10:30
Xiaochen Wang e0a04b11e4 scripts/kallsyms.c: fix potential segfault
Description:
This bug hardly appears during real kernel compiling,
 because the vmlinux symbols table is huge.

But we can still catch it under strict condition , as follows.
   $ echo "c101b97b T do_fork" | ./scripts/kallsyms --all-symbols
   #include <asm/types.h>
   ......
   ......
   .globl kallsyms_token_table
           ALGN
   kallsyms_token_table:
   Segmentation fault (core dumped)
   $

If symbols table is small, all entries in token_profit[0x10000] may
decrease to 0 after several calls of compress_symbols() in optimize_result().
In that case, find_best_token() always return 0 and
best_table[i] is set to "\0\0" and best_table_len[i] is set to 2.

As a result, expand_symbol(best_table[0]="\0\0", best_table_len[0]=2, buf)
in write_src() will run in infinite recursion until stack overflows,
causing segfault.

This patch checks the find_best_token() return value. If all entries in
token_profit[0x10000] become 0 according to return value, it breaks the loop
in optimize_result().
And expand_symbol() works well when best_table_len[i] is 0.

Signed-off-by: Xiaochen Wang <wangxiaochen0@gmail.com>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-05-12 17:23:40 +02:00
Jean Sacren ef894870c6 scripts/kallsyms: Enable error messages while hush up unnecessary warnings
As no error was handled, we wouldn't be able to know when an error does
occur. The fix preserves error messages while it doesn't let unnecessary
compiling warnings show up.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-09-29 16:18:27 +02:00
Himanshu Chauhan 71d41aed94 scripts/kallsyms: suppress build warning
Suppress a warn_unused_result warning.

fgets is called as a part of error handling.  It is called just to drop a
line and return immediately.  read_map is reading the file in a loop and
read_symbol reads line by line.  So I think there is no point in using
return value for useful checking.  Other checks like 3 items were returned
or !EOF have already been done.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-02-02 14:33:56 +01:00
Paul Mundt a9ece53c40 kallsyms: fix segfault in prefix_underscores_count()
Commit b478b782e1 "kallsyms, tracing: output
more proper symbol name" introduces a "bugfix" that introduces a segfault
in kallsyms in my configurations.

The cause is the introduction of prefix_underscores_count() which attempts
to count underscores, even in symbols that do not have them.  As a result,
it just uselessly runs past the end of the buffer until it crashes:

  CC      init/version.o
  LD      init/built-in.o
  LD      .tmp_vmlinux1
  KSYM    .tmp_kallsyms1.S
/bin/sh: line 1: 16934 Done                    sh-linux-gnu-nm -n .tmp_vmlinux1
     16935 Segmentation fault      | scripts/kallsyms > .tmp_kallsyms1.S
make: *** [.tmp_kallsyms1.S] Error 139

This simplifies the logic and just does a straightforward count.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Paulo Marques <pmarques@grupopie.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>		[2.6.30.x, 2.6.31.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23 07:39:30 -07:00
Mike Frysinger ac6ca5c86c kallsyms: fix inverted valid symbol checking
The previous commit (17b1f0de) introduced a slightly broken consolidation
of the memory text range checking.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-20 13:33:23 +02:00
Mike Frysinger 17b1f0de79 kallsyms: generalize text region handling
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-14 22:43:46 +02:00
Robin Getz 028f042613 kallsyms: support kernel symbols in Blackfin on-chip memory
The Blackfin arch has a discontiguous .text layout due to having on-chip
instruction memory and no virtual memory support.  As such, we need to
add explicit checks for these additional .text regions.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-06-14 22:43:45 +02:00
Lai Jiangshan b478b782e1 kallsyms, tracing: output more proper symbol name
Impact: bugfix, output more reliable symbol lookup result

Debug tools(dump_stack(), ftrace...) are like to print out symbols.
But it is always print out the first aliased symbol.(Aliased symbols
are symbols with the same address), and the first aliased symbol is
sometime not proper.

 # echo function_graph > current_tracer
 # cat trace
......
 1)   1.923 us    |    select_nohz_load_balancer();
 1) + 76.692 us   |  }
 1)               |  default_idle() {
 1)   ==========> |    __irqentry_text_start() {
 1)   0.000 us    |      native_apic_mem_write();
 1)               |      irq_enter() {
 1)   0.000 us    |        idle_cpu();
 1)               |        tick_check_idle() {
 1)   0.000 us    |          tick_check_oneshot_broadcast();
 1)               |          tick_nohz_stop_idle() {
......

It's very embarrassing, it ouputs "__irqentry_text_start()",
actually, it should output "smp_apic_timer_interrupt()".
(these two symbol are the same address, but "__irqentry_text_start"
is deemed to the first aliased symbol by scripts/kallsyms)

This patch puts symbols like "__irqentry_text_start" to the second
aliased symbols. And a more proper symbol name becomes the first.

Aliased symbols mostly come from linker script. The solution is
guessing "is this symbol defined in linker script", the symbols
defined in linker script will not become the first aliased symbol.

And if symbols are found to be equal in this "linker script provided"
criteria, symbols are sorted by the number of prefix underscores.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Paulo Marques <pmarques@grupopie.com>
LKML-Reference: <49BA06E2.7080807@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-14 09:55:04 +01:00
Sam Ravnborg 2ea038917b Revert "kbuild: strip generated symbols from *.ko"
This reverts commit ad7a953c52.

And commit: ("allow stripping of generated symbols under CONFIG_KALLSYMS_ALL")
            9bb482476c

These stripping patches has caused a set of issues:

1) People have reported compatibility issues with binutils due to
   lack of support for `--strip-unneeded-symbols' with objcopy 2.15.92.0.2
   Reported by: Wenji
2) ccache and distcc no longer works as expeced
   Reported by: Ted, Roland, + others
3) The installed modules increased a lot in size
   Reported by: Ted, Davej + others

Reported-by: Wenji Huang <wenji.huang@oracle.com>
Reported-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-01-14 21:38:20 +01:00
Jan Beulich 9bb482476c allow stripping of generated symbols under CONFIG_KALLSYMS_ALL
Building upon parts of the module stripping patch, this patch
introduces similar stripping for vmlinux when CONFIG_KALLSYMS_ALL=y.
Using CONFIG_KALLSYMS_STRIP_GENERATED reduces the overhead of
CONFIG_KALLSYMS_ALL from 245k/310k to 65k/80k for the (i386/x86-64)
kernels I tested with.

The patch also does away with the need to special case the kallsyms-
internal symbols by making them available even in the first linking
stage.

While it is a generated file, the patch includes the changes to
scripts/genksyms/keywords.c_shipped, as I'm unsure what the procedure
here is.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-12-19 22:47:10 +01:00
Sam Ravnborg aab34ac858 kbuild: filter away debug symbols from kernel symbols
Andi Kleen <andi@firstfloor.org>
reported that he saw a lot of symbols like this:

0000000000000b24 N DW.aio.h.903a6d92.2
0000000000000bce N DW.task_io_accounting.h.8d8de327.0
0000000000000bec N DW.hrtimer.h.c23659c6.0

in his System.map / kallsyms output.

Simple solution is to skip all debugging
symbols (they are marked 'N').

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Paulo Marques <pmarques@grupopie.com>
2008-05-19 20:07:58 +02:00
Bryan Wu c6495aaabf kallsyms: nuke all ChangeLog, this should be logged by git
Pointed out by Paulo:
  "When I wrote this initially, it was a mistake to add a Changelog in
   the first place, but I didn't know better at the time.

   If you're going to make changes to this file, please remove all the
   Changelog, instead of adding more entries to it.  The 'Changelog'
   should be kept by the version control system, and not the source code
   itself."

Cc: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:31 -07:00
Paulo Marques f2df3f65d0 kallsyms should prefer non weak symbols
When resolving symbol names from addresses with aliased symbol names,
kallsyms_lookup always returns the first symbol, even if it is a weak
symbol.

This patch changes this by sorting the symbols with the weak symbols last
before feeding them to the kernel.  This way the kernel runtime isn't
changed at all, only the kallsyms build system is changed.

Another side effect is that the symbols get sorted by address, too.  So,
even if future binutils version have some bug in "nm" that makes it fail to
correctly sort symbols by address, the kernel won't be affected by this.

Mathieu says:

  I created a module in LTTng that uses kallsyms to get the symbol
  corresponding to a specific system call address.  Unfortunately, all the
  unimplemented syscalls were all referring to the (same) weak symbol
  identifying an unrelated system call rather that sys_ni (or whatever
  non-weak symbol would be expected).  Kallsyms was dumbly returning the first
  symbol that matched.

  This patch makes sure kallsyms returns the non-weak symbol when there is
  one, which seems to be the expected result.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Looks-great-to: Rusty Russell <rusty@rustcorp.com.au>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:07 -08:00
Robin Getz a3b81113fb remove support for un-needed _extratext section
When passing a zero address to kallsyms_lookup(), the kernel thought it was
a valid kernel address, even if it is not.  This is because is_ksym_addr()
called is_kernel_extratext() and checked against labels that don't exist on
many archs (which default as zero).  Since PPC was the only kernel which
defines _extra_text, (in 2005), and no longer needs it, this patch removes
_extra_text support.

For some history (provided by Jon):
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019734.html
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019736.html
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019751.html

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jon Loeliger <jdl@freescale.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:01 -08:00
Linus Torvalds efffbeee5b Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: (33 commits)
  xtensa: use DATA_DATA in xtensa
  powerpc: add missing DATA_DATA to powerpc
  cris: use DATA_DATA in cris
  kallsyms: remove usage of memmem and _GNU_SOURCE from scripts/kallsyms.c
  kbuild: use -fno-optimize-sibling-calls unconditionally
  kconfig: reset generated values only if Kconfig and .config agree.
  kbuild: fix the warning when running make tags
  kconfig: strip 'CONFIG_' automatically in kernel configuration search
  kbuild: use POSIX BRE in headers install target
  Whitelist references from __dbe_table to .init
  modpost white list pattern adjustment
  kbuild: do section mismatch check on full vmlinux
  kbuild: whitelist references from variables named _timer to .init.text
  kbuild: remove hardcoded _logo names from modpost
  kbuild: remove hardcoded apic_es7000 from modpost
  kbuild: warn about references from .init.text to .exit.text
  kbuild: consolidate section checks
  kbuild: refactor code in modpost to improve maintainability
  kbuild: ignore section mismatch warnings originating from .note section
  kbuild: .paravirtprobe section is obsolete, so modpost doesn't need to handle it
  ...
2007-07-19 14:28:19 -07:00
Tejun Heo 9281acea6a kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
KSYM_NAME_LEN is peculiar in that it does not include the space for the
trailing '\0', forcing all users to use KSYM_NAME_LEN + 1 when allocating
buffer.  This is nonsense and error-prone.  Moreover, when the caller
forgets that it's very likely to subtly bite back by corrupting the stack
because the last position of the buffer is always cleared to zero.

This patch increments KSYM_NAME_LEN by one and updates code accordingly.

* off-by-one bug in asm-powerpc/kprobes.h::kprobe_lookup_name() macro
  is fixed.

* Where MODULE_NAME_LEN and KSYM_NAME_LEN were used together,
  MODULE_NAME_LEN was treated as if it didn't include space for the
  trailing '\0'.  Fix it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Paulo Marques <pmarques@grupopie.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:03 -07:00
Paulo Marques 7c5d249ad3 kallsyms: remove usage of memmem and _GNU_SOURCE from scripts/kallsyms.c
The only in-kernel user of "memmem" is scripts/kallsyms.c and it only
uses it to find tokens that are 2 bytes in size. It is trivial to
replace it with a simple function that finds 2-byte tokens.

This should help users from systems that don't have the memmem GNU
extension available.

Signed-off-by: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2007-07-17 14:36:08 +02:00
Jan Beulich aad094701c [PATCH] move kallsyms data to .rodata
Kallsyms data is never written to, so it can as well benefit from
CONFIG_DEBUG_RODATA.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:37 -08:00
Vivek Goyal 2c22d8baa9 [PATCH] relocatable kernel: Fix kallsyms on avr32 after relocatable kernel changes
o On some platforms like avr32, section init comes before .text and
  not necessarily a symbol's relative position w.r.t _text is positive.
  In such cases assembler detects the overflow and emits warning. This
  patch fixes it.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-12-07 02:14:10 +01:00
Eric W. Biederman fd593d1277 [PATCH] relocatable kernel: Kallsyms generate relocatable symbols
Print the addresses of non-absolute symbols relative to _text
so that ld will generate relocations.  Allowing a relocatable
kernel to relocate them.  We can't actually use the symbol names
because kallsyms includes static symbols that are not exported
from their object files.

Add the _text symbol definitions to the architectures which don't
define it otherwise linker will fail.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2006-12-07 02:14:04 +01:00
Jesper Juhl f1a136e0d0 [PATCH] kallsyms: handle malloc() failure
This fixes coverity bugs #398 and #397

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25 08:22:56 -08:00
Ralf Baechle 6f00df24ee [PATCH] Strip local symbols from kallsyms
Local symbols generated by gcc start with a `$'; no point in including them
in the kernel.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:20 -07:00
Paulo Marques b3dbb4ecd4 [PATCH] kallsyms: change compression algorithm
This patch changes the way the compression algorithm works.  The base
algorithm is similiar to the previous but we force the compressed token
size to 2.

Having a fixed size compressed token allows for a lot of optimizations, and
that in turn allows this code to run over *all* the symbols faster than it
did before over just a subset.

Having it work over all the symbols will make it behave better when symbols
change positions between passes, and the "inconsistent kallsyms" messages
should become less frequent.

In my tests the compression ratio was degraded by about 0.5%, but the
results will depend greatly on the number of symbols to compress.

Signed-off-by: Paulo Marques <pmarques@grupopie.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:18 -07:00
J.A. Magallon 61d9cdf2a9 [PATCH] kbuild: signed char fixes for scripts
This time I did not break anything... and they shut up gcc4 ;)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2005-07-27 22:27:08 +02:00
David Woodhouse 075d6eb16d [PATCH] ppc32: platform-specific functions missing from kallsyms.
The PPC32 kernel puts platform-specific functions into separate sections so
that unneeded parts of it can be freed when we've booted and actually
worked out what we're running on today.

This makes kallsyms ignore those functions, because they're not between
_[se]text or _[se]inittext.  Rather than teaching kallsyms about the
various pmac/chrp/etc sections, this patch adds '_[se]extratext' markers
for kallsyms.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-05 16:36:31 -07:00
Yoshinori Sato 41f11a4fa3 [PATCH] kallsyms C_SYMBOL_PREFIX support
kallsyms does not consider SYMBOL_PREFIX of C.  Consequently it does not
work on architectures using that prefix character (h8300, v850).

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:59:06 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00