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  1. 04 2月, 2017 1 次提交
    • A
      kbuild: modversions: add infrastructure for emitting relative CRCs · 56067812
      由 Ard Biesheuvel 提交于 
      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: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      56067812
  3. 11 12月, 2016 1 次提交
  5. 29 11月, 2016 2 次提交
  7. 10 11月, 2016 1 次提交
  9. 01 11月, 2016 1 次提交
  11. 23 10月, 2016 1 次提交
  13. 09 9月, 2016 1 次提交
    • S
      kbuild: allow architectures to use thin archives instead of ld -r · a5967db9
      由 Stephen Rothwell 提交于 
      ld -r is an incremental link used to create built-in.o files in build
subdirectories. It produces relocatable object files containing all
its input files, and these are are then pulled together and relocated
in the final link. Aside from the bloat, this constrains the final
link relocations, which has bitten large powerpc builds with
unresolvable relocations in the final link.

Alan Modra has recommended the kernel use thin archives for linking.
This is an alternative and means that the linker has more information
available to it when it links the kernel.

This patch enables a config option architectures can select, which
causes all built-in.o files to be built as thin archives. built-in.o
files in subdirectories do not get symbol table or index attached,
which improves speed and size. The final link pass creates a
built-in.o archive in the root output directory which includes the
symbol table and index. The linker then uses takes this file to link.

The --whole-archive linker option is required, because the linker now
has visibility to every individual object file, and it will otherwise
just completely avoid including those without external references
(consider a file with EXPORT_SYMBOL or initcall or hardware exceptions
as its only entry points). The traditional built works "by luck" as
built-in.o files are large enough that they're going to get external
references. However this optimisation is unpredictable for the kernel
(due to above external references), ineffective at culling unused, and
costly because the .o files have to be searched for references.
Superior alternatives for link-time culling should be used instead.

Build characteristics for inclink vs thinarc, on a small powerpc64le
pseries VM with a modest .config:

                                  inclink       thinarc
sizes
vmlinux                        15 618 680    15 625 028
sum of all built-in.o          56 091 808     1 054 334
sum excluding root built-in.o                   151 430

find -name built-in.o | xargs rm ; time make vmlinux
real                              22.772s       21.143s
user                              13.280s       13.430s
sys                                4.310s        2.750s

- Final kernel pulled in only about 6K more, which shows how
  ineffective the object file culling is.
- Build performance looks improved due to less pagecache activity.
  On IO constrained systems it could be a bigger win.
- Build size saving is significant.

Side note, the toochain understands archives, so there's some tricks,
$ ar t built-in.o          # list all files you linked with
$ size built-in.o          # and their sizes
$ objdump -d built-in.o    # disassembly (unrelocated) with filenames

Implementation by sfr, minor tweaks by npiggin.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichal Marek <mmarek@suse.com>
      a5967db9
  15. 08 8月, 2016 1 次提交
    • A
      [kbuild] handle exports in lib-y objects reliably · 7f2084fa
      由 Al Viro 提交于 
      Collect the symbols exported by anything that goes into lib.a and
add an empty object (lib-exports.o) with explicit undefs for each
of those to obj-y.

That allows to relax the rules regarding the use of exports in
lib-* objects - right now an object with export can be in lib-*
only if we are guaranteed that there always will be users in
built-in parts of the tree, otherwise it needs to be in obj-*.
As the result, we have an unholy mix of lib- and obj- in lib/Makefile
and (especially) in arch/*/lib/Makefile.  Moreover, a change in
generic part of the kernel can lead to mysteriously missing exports
on some configs.  With this change we don't have to worry about
that anymore.

One side effect is that built-in.o now pulls everything with exports
from the corresponding lib.a (if such exists).  That's exactly what
we want for linking vmlinux and fortunately it's almost the only thing
built-in.o is used in.  arch/ia64/hp/sim/boot/bootloader is the only
exception and it's easy to get rid of now - just turn everything in
arch/ia64/lib into lib-* and don't bother with arch/ia64/lib/built-in.o
anymore.

[AV: stylistic fix from Michal folded in]
Acked-by: NMichal Marek <mmarek@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      7f2084fa
  17. 08 6月, 2016 1 次提交
  19. 20 4月, 2016 2 次提交
  21. 30 3月, 2016 2 次提交
    • N
      kbuild: de-duplicate fixdep usage · e4aca459
      由 Nicolas Pitre 提交于 
      The generation and postprocessing of automatic dependency rules is
duplicated in rule_cc_o_c, rule_as_o_S and if_changed_dep. Since
this is not a trivial one-liner action, it is now abstracted under
cmd_and_fixdep to simplify things and make future changes in this area
easier.

In the rule_cc_o_c and rule_as_o_S cases that means the order of some
commands has been altered, namely fixdep and related file manipulations
are executed earlier, but they didn't depend on those commands that now
execute later.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
      e4aca459
    • N
      kbuild: record needed exported symbols for modules · 9895c03d
      由 Nicolas Pitre 提交于 
      Kernel modules are partially linked object files with some undefined
symbols that are expected to be matched with EXPORT_SYMBOL() entries
from elsewhere.

Each .tmp_versions/*.mod file currently contains two line of text
separated by a newline character. The first line has the actual module
file name while the second line has a list of object files constituting
that module. Those files are parsed by modpost (scripts/mod/sumversion.c),
scripts/Makefile.modpost, scripts/Makefile.modsign, etc.  Only the
modpost utility cares about the second line while the others retrieve
only the first line.

Therefore we can add a third line to record the list of undefined symbols
aka required EXPORT_SYMBOL() entries for each module into that file
without breaking anything. Like for the second line, symbols are separated
by a blank and the list is terminated with a newline character.

To avoid needless build overhead, the undefined symbols extraction is
performed only when CONFIG_TRIM_UNUSED_KSYMS is selected.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
      9895c03d
  23. 05 3月, 2016 1 次提交
  25. 29 2月, 2016 1 次提交
  27. 25 11月, 2015 1 次提交
    • M
      kbuild: Allow to specify composite modules with modname-m · cf4f2193
      由 Michal Marek 提交于 
      This allows to write

  drm-$(CONFIG_AGP) += drm_agpsupport.o

without having to handle CONFIG_AGP=y vs. CONFIG_AGP=m. Only support
this syntax for modules, since built-in code depending on something
modular cannot work and init/Makefile actually relies on the current
semantics. There are a few drivers which adapted to the current
semantics out of necessity; these are fixed to also work when the
respective subsystem is modular.

Acked-by: Peter Chen <peter.chen@freescale.com> [chipidea]
Signed-off-by: NMichal Marek <mmarek@suse.com>
      cf4f2193
  29. 29 1月, 2015 1 次提交
  31. 02 10月, 2014 1 次提交
  33. 19 8月, 2014 1 次提交
    • M
      kbuild: handle multi-objs dependency appropriately · c8589d1e
      由 Masahiro Yamada 提交于 
      The comment in scripts/Makefile.build says as follows:

  We would rather have a list of rules like
        foo.o: $(foo-objs)
  but that's not so easy, so we rather make all composite objects depend
  on the set of all their parts

This commit makes it possible!

For example, assume a Makefile like this

  obj-m = foo.o bar.o
  foo-objs := foo1.o foo2.o
  bar-objs := bar1.o bar2.o

Without this patch, foo.o depends on all of
foo1.o foo2.o bar1.o bar2.o.
It looks funny that foo.o is regenerated when bar1.c is updated.

Now we can handle the dependency of foo.o and bar.o separately.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>
      c8589d1e
  35. 30 4月, 2014 1 次提交
  37. 17 4月, 2014 1 次提交
  39. 10 4月, 2014 1 次提交
  41. 14 2月, 2014 1 次提交
  43. 20 3月, 2013 1 次提交
    • J
      genksyms: pass symbol-prefix instead of arch · d70f82ac
      由 James Hogan 提交于 
      Pass symbol-prefix to genksyms instead of arch, so that the decision
what symbol prefix to use is kept in one place.

Basically genksyms used to take a -a $ARCH argument and it used that to
determine whether to add an underscore symbol prefix. It's now changed
to take a -s $SYMBOL_PREFIX argument so that the caller decides whether
a symbol prefix is required. The build system then uses
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX to determine whether to pass the
argument.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      d70f82ac
  45. 08 10月, 2012 1 次提交
    • D
      X.509: Add simple ASN.1 grammar compiler · 4520c6a4
      由 David Howells 提交于 
      Add a simple ASN.1 grammar compiler.  This produces a bytecode output that can
be fed to a decoder to inform the decoder how to interpret the ASN.1 stream it
is trying to parse.

Action functions can be specified in the grammar by interpolating:

	({ foo })

after a type, for example:

	SubjectPublicKeyInfo ::= SEQUENCE {
		algorithm		AlgorithmIdentifier,
		subjectPublicKey	BIT STRING ({ do_key_data })
		}

The decoder is expected to call these after matching this type and parsing the
contents if it is a constructed type.

The grammar compiler does not currently support the SET type (though it does
support SET OF) as I can't see a good way of tracking which members have been
encountered yet without using up extra stack space.

Currently, the grammar compiler will fail if more than 256 bytes of bytecode
would be produced or more than 256 actions have been specified as it uses
8-bit jump values and action indices to keep space usage down.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      4520c6a4
  47. 26 1月, 2012 1 次提交
  49. 31 8月, 2011 1 次提交
  51. 19 5月, 2011 1 次提交
  53. 17 5月, 2011 3 次提交
  55. 02 5月, 2011 1 次提交
  57. 29 4月, 2011 1 次提交
  59. 28 4月, 2011 1 次提交
    • S
      kbuild: implement several W= levels · 28bc20dc
      由 Sam Ravnborg 提交于 
      Building a kernel with "make W=1" produces far too much noise to be
useful.

Divide the warning options in three groups:

    W=1 - warnings that may be relevant and does not occur too often
    W=2 - warnings that occur quite often but may still be relevant
    W=3 - the more obscure warnings, can most likely be ignored

When building the whole kernel, those levels produce:

W=1 - 4859 warnings
W=2 - 1394 warnings
W=3 - 86666 warnings

respectively. Warnings have been counted with Geert's script at

http://www.kernel.org/pub/linux/kernel/people/geert/linux-log/linux-log-summary.pl

Many warnings occur from .h files so fixing one file may have a nice
effect on the total number of warnings.

With these changes I am actually tempted to try W=1 now and then.
Previously there was just too much noise.

Borislav:

- make the W= levels exclusive
- move very noisy and making little sense for the kernel warnings to W=3
- drop -Woverlength-strings due to useless warning message
- copy explanatory text for the different warning levels to 'make help'
- recount warnings per level
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NBorislav Petkov <bp@alien8.de>
Cc: Dave Jones <davej@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>
      28bc20dc
  61. 20 4月, 2011 1 次提交
  63. 18 4月, 2011 1 次提交
  65. 09 3月, 2011 1 次提交
  67. 19 11月, 2010 1 次提交
    • W
      ftrace: Speed up recordmcount · 45677454
      由 Wu Zhangjin 提交于 
      cmd_record_mcount is used to locate the _mcount symbols in the object
files, only the files compiled with -pg has the _mcount symbol, so, it
is only needed for such files, but the current cmd_record_mcount is used
for all of the object files, so, we need to fix it and speed it up.

Since -pg may be removed by the method used in kernel/trace/Makefile:

ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS))

Or may be removed by the method used in arch/x86/kernel/Makefile:

CFLAGS_REMOVE_file.o = -pg

So, we must check the last variable stores the compiling flags, that is
c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in
scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already
filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags
has less symbols, therefore, we only need to check _c_flags.

---------------
Changes from v1:

  o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough
  o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg
  (feedback from Steven Rostedt <rostedt@goodmis.org>)
Acked-by: NMichal Marek <mmarek@suse.cz>
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com>

[ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      45677454
  69. 19 10月, 2010 1 次提交
    • S
      ftrace: Remove recursion between recordmcount and scripts/mod/empty · d7b4d6de
      由 Steven Rostedt 提交于 
      When DYNAMIC_FTRACE is enabled and we use the C version of recordmcount,
all objects are run through the recordmcount program to create a
separate section that stores all the callers of mcount.

The build process has a special file: scripts/mod/empty.o. This is
built from empty.c which is literally an empty file (except for a
single comment). This file is used to find information about the target
elf format, like endianness and word size.

The problem comes up when we need to build recordmcount. The
build process requires that empty.o is built first. The build rules
for empty.o will try to execute recordmcount on the empty.o file.
We get an error that recordmcount does not exist.

To avoid this recursion, the build file will skip running recordmcount
if the file that it is building is script/mod/empty.o.

[ extra comment Suggested-by: Sam Ravnborg <sam@ravnborg.org> ]
Reported-by: NIngo Molnar <mingo@elte.hu>
Tested-by: NIngo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      d7b4d6de