If .config has been edited, there will be a silentoldconfig run:

  $ make defconfig
  ...
  $ make kernelrelease
  scripts/kconfig/conf --silentoldconfig Kconfig
  3.16.0-rc1+

Recently, kbuild started to print the name of the build directory when
using O=

  $ make O=build kernelrelease
  make[1]: Entering directory `/dev/shm/mmarek/linux-2.6/build'
  3.16.0-rc1+

Since these targets are often used in scripts, add a hint to use make -s
to the help text.
Suggested-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

The directory include/config is used only for
silentoldconfig, localmodconfig, localyesconfig.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

There are no generated files under include/linux directory.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

On architectures that setup CROSS_COMPILE in their arch/*/Makefile
(arc, blackfin, m68k, mips, parisc, score, sh, tile, unicore32, xtensa),
cc-option and cc-disable-warning may check against the wrong compiler,
causing errors like

    cc1: error: unrecognized command line option "-Wno-maybe-uninitialized"

if the host gcc supports a compiler option, while the cross compiler
doesn't support that option.

Move all logic using cc-option or cc-disable-warning below the inclusion
of the arch's Makefile to fix this.

Introduced by
  - commit e74fc973 ("Turn off
    -Wmaybe-uninitialized when building with -Os"),
  - commit 61163efa ("kbuild: LLVMLinux:
    Add Kbuild support for building kernel with Clang").

As -Wno-maybe-uninitialized requires a quite recent gcc (gcc 4.6.3 on
Ubuntu 12.04 LTS doesn't support it), this only showed up recently (gcc
4.8.2 on Ubuntu 14.04 LTS does support it).
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Both gcc (well, actually gnu as) and clang support the "-Wa,-gdwarf-2" option
(though clang does not support "-Wa,--gdwarf-2"). Since these flags are equivalent
in meaning, this patch uses the one which is better supported across compilers.
Signed-off-by: NBehan Webster <behanw@converseincode.com>

When doing make O=<subdir>, use '..' to refer to the source tree. This
allows for more readable compiler messages, and, more importantly, it
sets the VPATH to '..', so filenames in WARN_ON() etc. will be shorter.
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

When not using O=, $(srctree) refers to the same directory as
$(objtree), so we can set it to '.' as well. This makes the default
include path more compact and results in more readable messages from the
compiler. The only case where we need the absolute path is when creating
the 'source' symlink in /lib/modules.
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

The main Makefile sets its working directory to the object tree and
never changes it again. Therefore, we can use '.' instead of the
absolute path. The only case where we need the absolute path is when
creating the 'build' symlink in /lib/modules.
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Kbuild is supposed to support mixed targets. (%config and build targets)

But "make all" did nothing if it was run with configuration targets.
For example,

  $ LANG=C make defconfig all
    HOSTCC  scripts/basic/fixdep
    HOSTCC  scripts/kconfig/conf.o
    SHIPPED scripts/kconfig/zconf.tab.c
    SHIPPED scripts/kconfig/zconf.lex.c
    SHIPPED scripts/kconfig/zconf.hash.c
    HOSTCC  scripts/kconfig/zconf.tab.o
    HOSTLD  scripts/kconfig/conf
  *** Default configuration is based on 'x86_64_defconfig'
  #
  # configuration written to .config
  #
  make: Nothing to be done for `all'.

This commits allows "make %config all" and makes sure
mixed targets are built one by one in the given order.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Michal Marek <mmarek@suse.cz>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

W=... provides extra gcc checks.

Having such code in scripts/Makefile.build results in the same flags
being added to KBUILD_CFLAGS multiple times becuase
scripts/Makefile.build is invoked every time Kbuild descends into
the subdirectories.

Since the top Makefile is already too cluttered, this commit moves
all of extra gcc check stuff to a new file scripts/Makefile.extrawarn,
which is included from the top Makefile.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Add support to toplevel Makefile for compiling with clang, both for
HOSTCC and CC. Use cc-option to prevent gcc option from breaking clang, and
from clang options from breaking gcc.

Clang 3.4 semantics are the same as gcc semantics for unsupported flags. For
unsupported warnings clang 3.4 returns true but shows a warning and gcc shows
a warning and returns false.
Signed-off-by: NBehan Webster <behanw@converseincode.com>
Signed-off-by: NJan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: NMark Charlebois <charlebm@gmail.com>
Cc: PaX Team <pageexec@freemail.hu>

objdiff is useful when doing large code cleanups.  For example, when
removing checkpatch warnings and errors from new drivers in the staging
tree.

objdiff can be used in conjunction with a git rebase to confirm that
each commit made no changes to the resulting object code.  It has the
same return values as diff(1).

This was written specifically to support adding the skein and threefish
cryto drivers to the staging tree.  I needed a programmatic way to
confirm that commits changing >90% of the lines didn't inadvertently
change the code.

Temporary files (objdump output) are stored in

  /path/to/linux/.tmp_objdiff

'make mrproper' will remove this directory.
Signed-off-by: NJason Cooper <jason@lakedaemon.net>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

Kbuild supports saving output files in a separate directory.
But the build directory must be created beforehand. For example,

  $ mkdir -p dir/to/store/output/files
  $ make O=dir/to/store/output/files defconfig

Creating a build directory automatically would be useful.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

'.*.cmd' files are cleaned-up by "make clean".
The same pattern in "make distclean" is unnecessary.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

As of v3.7, the UAPI changes relocated headers around such that the
kernel version header lived in a new place.

If a person is bisecting and if you go back to pre-UAPI days,
you will create an include/linux/version.h  -- then if you checkout a
post-UAPI kernel, and even run "make distclean" it still won't delete
that old version file.  So you get a situation like this:

$ grep -R LINUX_VERSION_CODE include/
include/generated/uapi/linux/version.h:#define LINUX_VERSION_CODE 200192
include/linux/version.h:#define LINUX_VERSION_CODE 132646

The value in that second line is representative of a v2.6.38 version.
And it will be sourced/used, hence leading to strange behaviours, such
as drivers/staging content (which typically hasn't been purged of version
ifdefs) failing to build.

Since it is a subtle mode of failure, lets always clobber the old
file when doing a distclean.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

According to Documentation/Changes, make 3.80 is still being supported
for building the kernel, hence make files must not make (unconditional)
use of features introduced only in newer versions.  Commit 8779657d
("stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG") however
introduced an "else ifdef" construct which make 3.80 doesn't understand.

Also correct a warning message still referencing the old config option
name.

Apart from that I question the use of "ifdef" here (but it was used that
way already prior to said commit): ifeq (,y) would seem more to the
point.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

An extra parenthesis typo introduced in 19952a92 ("stackprotector:
Unify the HAVE_CC_STACKPROTECTOR logic between architectures") is
causing the following error when CONFIG_CC_STACKPROTECTOR_REGULAR is
enabled:

  Makefile:608: Cannot use CONFIG_CC_STACKPROTECTOR: -fstack-protector not supported by compiler
  Makefile:608: *** missing separator.  Stop.
Signed-off-by: NFathi Boudra <fathi.boudra@linaro.org>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Unlike other build products in the Linux kernel, there is no 'make
*install' mechanism to put devicetree blobs in a standard place.

This commit adds a new 'dtbs_install' make target which copies all of
the dtbs into the INSTALL_DTBS_PATH directory. INSTALL_DTBS_PATH can be
set before calling make to change the default install directory. If not
set then it defaults to:

	$INSTALL_PATH/dtbs/$KERNELRELEASE.

This is done to keep dtbs from different kernel versions separate until
things have settled down.  Once the dtbs are stable, and not so strongly
linked to the kernel version, the devicetree files will most likely move
to their own repo.  Users will need to upgrade install scripts at that
time.

v7: (reworked by Grant Likely)
- Moved rules from arch/arm/Makefile to arch/arm/boot/dts/Makefile so
  that each dtb install could have a separate target and be reported as
  part of the make output.
- Fixed dependency problem to ensure $KERNELRELEASE is calculated before
  attempting to install
- Removed option to call external script. Copying the files should be
  sufficient and a build system can post-process the install directory.
  Despite the fact an external script is used for installing the kernel,
  I don't think that is a pattern that should be encouraged. I would
  rather see buildroot type tools post process the install directory to
  rename or move dtb files after installing to a staging directory.
  - Plus it is easy to add a hook after the fact without blocking the
    rest of this feature.
- Move the helper targets into scripts/Makefile.lib with the rest of the
  common dtb rules
Signed-off-by: NJason Cooper <jason@lakedaemon.net>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <robh+dt@kernel.org>

CONFIG_MODVERSIONS=y results in a .mod.c for every compiled file in the
kernel. Issuing a 'make cscope' on a compiled kernel tree results in
the cscope files containing *.mod.c files.

[prarit@prarit linux]# make cscope
[prarit@prarit linux]# cat cscope.files | grep mod.c | wc -l
4807

These files are not useful for cscope and should be ignored. For example,

   #   line  filename / context / line
   1    105  arch/x86/kvm/kvm-intel.mod.c <<GLOBAL>>
             { 0x618911fc, __VMLINUX_SYMBOL_STR(numa_node) },
   2    508  drivers/block/mtip32xx/mtip32xx.h <<GLOBAL>>
             int numa_node;
   3     55  drivers/block/mtip32xx/mtip32xx.mod.c <<GLOBAL>>
             { 0x618911fc, __VMLINUX_SYMBOL_STR(numa_node) },
   4     37  drivers/cpufreq/acpi-cpufreq.mod.c <<GLOBAL>>
             { 0x618911fc, __VMLINUX_SYMBOL_STR(numa_node) },
   <snip>

Add an export to RCS_FIND_IGNORE so it can be used in scripts/tags.sh
and add explicitly ignore *.mod.c files.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMichal Marek <mmarek@suse.cz>