gcc-4.7 and higher add a lot of false positive warnings about
potential uses of uninitialized warnings, but only when optimizing
for size (-Os). This is the default when building allyesconfig,
which turns on CONFIG_CC_OPTIMIZE_FOR_SIZE.

In order to avoid getting a lot of patches that initialize such
variables and accidentally hide real errors along the way, let's
just turn off this warning on the respective gcc versions
when building with size optimizations. The -Wmaybe-uninitialized
option was introduced in the same gcc version (4.7) that is now
causing the false positives, so there is no effect on older compilers.

A side effect is that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE,
we might now see /fewer/ warnings about possibly uninitialized
warnings than with -O2, but that is still much better than seeing
warnings known to be bogus.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

The source tree can contain lots of uninteresting data like tag or
cscope files, packaging which slows down make rpm needlessly. It can
also break the build, if the tree contains an unrelated file named
*.spec. The downside of this change is that new subdirectories have to
be added to the KBUILD_ALLDIRS variable in the top-level Makefile. The
upside is that the behavior is more predictable.

Signed-off-by: Michal Marek <mmarek@suse.cz>

The headers are now needed inside scripts/mod since 6543becf
("mod/file2alias: make modalias generation safe for cross compiling").

Reported-and-tested-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Reported-and-tested-by: "Jon Medhurst (Tixy)" <tixy@linaro.org>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

We need to hand down parallel build options like the internal make
--jobserver-fds one so that parallel builds can also happen when
building perf from the toplevel directory.

Make it so #1!

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1361374353-30385-3-git-send-email-bp@alien8.de


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
"_".  But Al Viro broke this in "consolidate cond_syscall and
SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
do so.

Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
prefix it so something.  So various places define helpers which are
defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:

1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
   CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
   for pasting.

(arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).

Let's solve this properly:
1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
2) Make linux/export.h usable from asm.
3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().
4) Make everyone use them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com> (metag)

Newer gcc enables the var-tracking pass with -g to keep track which
registers contain which variables. This is one of the slower passes in gcc.

With reduced debug info (aimed at objdump -S, but not using a full debugger)
we don't need this fine grained tracking. But it was still enabled
because -g was enabled. Disable it explicitely for DEBUG_INFO_REDUCED.

On my 8T workstation this gives me about a 12 second gain in building
a reasonable kernel config (2min16 vs 2min28) with DEBUG_INFO_REDUCED.
With full DEBUG_INFO it takes 2min46

The actual improvement in user time taken by the compiler is much higher
(all CPU combined user time 15min5s vs 16m30 before)
but the usual amdahl bottleneck on the linker prevents more speedup.
It still saves some more energy and keeps cycles for other things.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

On architectures which have symbol prefixes, depmod emits lots of
warnings like this:

WARNING: $module.ko needs unknown symbol $symbol

This is because depmod isn't being passed the -P <symbol_prefix>
arguments to specify the symbol prefix to ignore. This option is
included since the 3.13 release of module-init-tools.

Update scripts/depmod.sh to take extra arguments for the symbol prefix
(required but may be empty), and update the main Makefile to always pass
"$(CONFIG_SYMBOL_PREFIX)" to scripts/depmod.sh.

If the provided symbol prefix is non-empty, scripts/depmod.sh checks if
depmod --version reports module-init-tools with a version number < 3.13
otherwise it appends -P $SYMBOL_PREFIX to the depmod command line.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Signed-off-by: Michal Marek <mmarek@suse.cz>

To allow the builder to sign only a subset of modules, or to sign the
modules using a key that is not available on the build machine, add
CONFIG_MODULE_SIG_ALL. If this option is unset, no modules will be
signed during build. The default is 'y', to preserve the current
behavior.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Make the script usable without a .config file.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Use the target compiler to compute the offsets for the fields of the
device_id structures, so that it won't be broken by different alignments
between the host and target ABIs.

This also fixes missing endian corrections for some modaliases.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

By popular demand, arch/aarch64 is now known as arch/arm64. However,
uname -m (and indeed the GNU triplet) still use aarch64 as the machine
string.

This patch fixes native builds of both the kernel and perf tools by
updating the relevant Makefiles to munge the output of uname -m and
set the ARCH variable appropriately.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

It is easy to waste a bunch of time when one takes a 32-bit .config
from a test machine and try to build it on a faster 64-bit system, and
its existing setting of CONFIG_64BIT=n gets *changed* to match the
build host.  Similarly, if one has an existing build tree it is easy
to trash an entire build tree that way.

This is because the default setting for $ARCH when discovered from
'uname' is one of the legacy pre-x86-merge values (i386 or x86_64),
which effectively force the setting of CONFIG_64BIT to match. We should
default to ARCH=x86 instead, finally completing the merge that we
started so long ago.

This patch preserves the behaviour of the legacy ARCH settings for commands
such as:

   make ARCH=x86_64 randconfig
   make ARCH=i386 randconfig

... since making the value of CONFIG_64BIT actually random in that situation
is not desirable.

In time, perhaps we can retire this legacy use of the old ARCH= values.
We already have a way to override values for *any* config option, using
$KCONFIG_ALLCONFIG, so it could be argued that we don't necessarily need
to keep ARCH={i386,x86_64} around as a special case just for overriding
CONFIG_64BIT.

We'd probably at least want to add a way to override config options from
the command line ('make CONFIG_FOO=y oldconfig') before we talk about doing
that though.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1356040315.3198.51.camel@shinybook.infradead.org


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

If CONFIG_MODULE_SIG is set, and 'make modules_sign' is called then this
patch will cause the modules to get a signature appended.  The make target
is intended to be run after 'make modules_install', and will modify the
modules in-place in the installed location.  It can be used to produce
signed modules after they have been processed by distribution build
scripts.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (minor typo fix)

Since commit 1f2bfbd0 "kbuild:
link of vmlinux moved to a script" make clean with M=<dir>
argument (so cleaning external module) removes vmlinux,
System.map and couple of other files from the *main* kernel
build directory! This not what was happening before and almost
certainly not what one would expect.

This patch moves makes the clean target of the script called
only when !KBUILD_EXTMOD.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Cc: stable@vger.kernel.org [v3.5+]
Signed-off-by: Michal Marek <mmarek@suse.cz>

Verbose output variable is unnecessary because the command's echo is
already surpressed. Additionally because the block defines skip-makefile
the variable Q is not defined within the makefile, which can cause
problems if Q is defined in the users environment.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

Honour the O= flag that was passed to a higher level Makefile and then passed
down as part of a tool build.

To make this work, the top-level Makefile passes the original O= flag and
subdir=tools to the tools/Makefile, and that in turn passes
subdir=$(O)/$(subdir)/foodir when building tool foo in directory
$(O)/$(subdir)/foodir (where the intervening slashes aren't added if an
element is missing).

For example, take perf.  This is found in tools/perf/.  Assume we're building
into directory ~/zebra/, so we pass O=~/zebra to make.  Dependening on where
we run the build from, we see:

	make run in dir		$(OUTPUT) dir
	=======================	==================
	linux			~/zebra/tools/perf/
	linux/tools		~/zebra/perf/
	linux/tools/perf	~/zebra/

and if O= is not set, we get:

	make run in dir		$(OUTPUT) dir
	=======================	==================
	linux			linux/tools/perf/
	linux/tools		linux/tools/perf/
	linux/tools/perf	linux/tools/perf/

The output directories are created by the descend function if they don't
already exist.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1378.1352379110@warthog.procyon.org.uk


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Honour the O= flag that was passed to a higher level Makefile and then passed
down as part of a tool build.

To make this work, the top-level Makefile passes the original O= flag and
subdir=tools to the tools/Makefile, and that in turn passes
subdir=$(O)/$(subdir)/foodir when building tool foo in directory
$(O)/$(subdir)/foodir (where the intervening slashes aren't added if an
element is missing).

For example, take perf.  This is found in tools/perf/.  Assume we're building
into directory ~/zebra/, so we pass O=~/zebra to make.  Dependening on where
we run the build from, we see:

	make run in dir		$(OUTPUT) dir
	=======================	==================
	linux			~/zebra/tools/perf/
	linux/tools		~/zebra/perf/
	linux/tools/perf	~/zebra/

and if O= is not set, we get:

	make run in dir		$(OUTPUT) dir
	=======================	==================
	linux			linux/tools/perf/
	linux/tools		linux/tools/perf/
	linux/tools/perf	linux/tools/perf/

The output directories are created by the descend function if they don't
already exist.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1378.1352379110@warthog.procyon.org.uk


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>