Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Makefile.clean descends into $(subdir-y).  Dummy assignment to subdir-
is meaningless.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Paul Moore <paul@paul-moore.com>

Swap the order of ".PHONY: $(PHONY)" and "PHONY += FORCE"
so that FORCE is correctly specified as a .PHONY target.

Use a preferred way for specifying $(subdirs) as .PHONY targets.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

These two targets are added to "targets".  Their directories are
automatically created.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The previous commit largely optimized the object directory creation.
We can optimize it more for incremental build.

There are already *.cmd files in the output directory.  The existing
*.cmd files have been picked up by $(wildcard ...).  Obviously,
directories containing them exist too, so we can skip "mkdir -p".

With this, Kbuild runs almost zero "mkdir -p" in incremental building.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

For the out-of-tree build, scripts/Makefile.build creates output
directories, but this operation is not efficient.

scripts/Makefile.lib calculates obj-dirs as follows:

  obj-dirs := $(dir $(multi-objs) $(obj-y))

Please notice $(sort ...) is not used here.  Usually the result is
as many "./" as objects here.

For a lot of duplicated paths, the following command is invoked.

  _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))

Then, the costly shell command is run over and over again.

I see many points for optimization:

[1] Use $(sort ...) to cut down duplicated paths before passing them
    to system call
[2] Use single $(shell ...) instead of repeating it with $(foreach ...)
    This will reduce forking.
[3] We can calculate obj-dirs more simply.  Most of objects are already
    accumulated in $(targets).  So, $(dir $(targets)) is fine and more
    comprehensive.

I also removed ugly code in arch/x86/entry/vdso/Makefile.  This is now
really unnecessary.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Douglas Anderson <dianders@chromium.org>

The variable "targets" contains object paths for which existing .*.cmd
files should be included.

scripts/Makefile.build automatically adds $(MAKECMDGOALS) to "targets"
as follows:

  targets += $(extra-y) $(MAKECMDGOALS) $(always)

The $(MAKECMDGOALS) is a PHONY target in several places.  PHONY targets
never create .*.cmd files.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

I do not see any reason why $(wildcard ...) needs to be called twice
for computing cmd_files.  Remove the first one.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Currently, the existence of $(dir $(make-cache)) is always checked,
and created if it is missing.

We can avoid unnecessary system calls by some tricks.

[1] If KBUILD_SRC is unset, we are building in the source tree.
    The output directory checks can be entirely skipped.
[2] If at least one cache data is found, it means the cache file
    was included.  Obviously its directory exists.  Skip "mkdir -p".
[3] If Makefile does not contain any call of __run-and-store, it will
    not create a cache file.  No need to create its directory.
[4] The "mkdir -p" should be only invoked by the first call of
    __run-and-store
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

You can not select KBUILD_DEFCONFIG depending on any CONFIG option
because include/config/auto.conf is not included when building config
targets.  So, CONFIG_SUPERH32 is never set during the configuration,
then cayman_defconfig is always chosen.

This commit provides a sensible way to choose shx3/cayman_defconfig.

arch/sh/Kconfig sets either SUPERH32 or SUPERH64 depending on ARCH
environment, like follows:

  config SUPERH32
          def_bool ARCH = "sh"

          ...

  config SUPERH64
          def_bool ARCH = "sh64"

It should make sense to choose the default defconfig by ARCH,
like arch/sparc/Makefile.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

I was not seeing my linker flags getting added when using ld-option when
cross compiling with Clang. Upon investigation, this seems to be due to
a difference in how GCC vs Clang handle cross compilation.

GCC is configured at build time to support one backend, that is implicit
when compiling.  Clang is explicit via the use of `-target <triple>` and
ships with all supported backends by default.

GNU Make feature test macros that compile then link will always fail
when cross compiling with Clang unless Clang's triple is passed along to
the compiler. For example:

$ clang -x c /dev/null -c -o temp.o
$ aarch64-linux-android/bin/ld -E temp.o
aarch64-linux-android/bin/ld:
unknown architecture of input file `temp.o' is incompatible with
aarch64 output
aarch64-linux-android/bin/ld:
warning: cannot find entry symbol _start; defaulting to
0000000000400078
$ echo $?
1

$ clang -target aarch64-linux-android- -x c /dev/null -c -o temp.o
$ aarch64-linux-android/bin/ld -E temp.o
aarch64-linux-android/bin/ld:
warning: cannot find entry symbol _start; defaulting to 00000000004002e4
$ echo $?
0

This causes conditional checks that invoke $(CC) without the target
triple, then $(LD) on the result, to always fail.
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The cache files are only cleaned away by "make clean".  If you continue
incremental builds, the cache files will grow up little by little.
It is not a big deal in general use cases because compiler flags do not
change quite often.

However, if you do build-test for various architectures, compilers, and
kernel configurations, you will end up with huge cache files soon.

When the cache file exceeds 1000 lines, shrink it down to 500 by "tail".
The Least Recently Added lines are cut. (not Least Recently Used)
I hope it will work well enough.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

Some $(call cc-option,...) are invoked very early, even before
KBUILD_CFLAGS, etc. are initialized.

The returned string from $(call cc-option,...) depends on
KBUILD_CPPFLAGS, KBUILD_CFLAGS, and GCC_PLUGINS_CFLAGS.

Since they are exported, they are not empty when the top Makefile
is recursively invoked.

The recursion occurs in several places.  For example, the top
Makefile invokes itself for silentoldconfig.  "make tinyconfig",
"make rpm-pkg" are the cases, too.

In those cases, the second call of cc-option from the same line
runs a different shell command due to non-pristine KBUILD_CFLAGS.

To get the same result all the time, KBUILD_* and GCC_PLUGINS_CFLAGS
must be initialized before any call of cc-option.  This avoids
garbage data in the .cache.mk file.

Move all calls of cc-option below the config targets because target
compiler flags are unnecessary for Kconfig.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

These are a few stragglers that I left out of the original patch to
cache calls to the C compiler ("kbuild: Add a cache for generated
variables") because they bleed out into the main Makefile and thus
uglify things a little bit.  The idea is the same here, though.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

While timing a "no-op" build of the kernel (incrementally building the
kernel even though nothing changed) in the Chrome OS build system I
found that it was much slower than I expected.

Digging into things a bit, I found that quite a bit of the time was
spent invoking the C compiler even though we weren't actually building
anything.  Currently in the Chrome OS build system the C compiler is
called through a number of wrappers (one of which is written in
python!) and can take upwards of 100 ms to invoke even if we're not
doing anything difficult, so these invocations of the compiler were
taking a lot of time.  Worse the invocations couldn't seem to take
advantage of the multiple cores on my system.

Certainly it seems like we could make the compiler invocations in the
Chrome OS build system faster, but only to a point.  Inherently
invoking a program as big as a C compiler is a fairly heavy
operation.  Thus even if we can speed the compiler calls it made sense
to track down what was happening.

It turned out that all the compiler invocations were coming from
usages like this in the kernel's Makefile:

KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)

Due to the way cc-option and similar statements work the above
contains an implicit call to the C compiler.  ...and due to the fact
that we're storing the result in KBUILD_CFLAGS, a simply expanded
variable, the call will happen every time the Makefile is parsed, even
if there are no users of KBUILD_CFLAGS.

Rather than redoing this computation every time, it makes a lot of
sense to cache the result of all of the Makefile's compiler calls just
like we do when we compile a ".c" file to a ".o" file.  Conceptually
this is quite a simple idea.  ...and since the calls to invoke the
compiler and similar tools are centrally located in the Kbuild.include
file this doesn't even need to be super invasive.

Implementing the cache in a simple-to-use and efficient way is not
quite as simple as it first sounds, though.  To get maximum speed we
really want the cache in a format that make can natively understand
and make doesn't really have an ability to load/parse files. ...but
make _can_ import other Makefiles, so the solution is to store the
cache in Makefile format.  This requires coming up with a valid/unique
Makefile variable name for each value to be cached, but that's
solvable with some cleverness.

After this change, we'll automatically create a ".cache.mk" file that
will contain our cached variables.  We'll load this on each invocation
of make and will avoid recomputing anything that's already in our
cache.  The cache is stored in a format that it shouldn't need any
invalidation since anything that might change should affect the "key"
and any old cached value won't be used.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

$(kbuild-file) and Kbuild.include are included before the default
target "all".

We will add a target into Kbuild.include.  In advance, add a forward
declaration of the default target.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

Accumulate subdir-{cc,as}flags-y directly to KBUILD_{A,C}FLAGS.
Remove KBUILD_SUBDIR_{AS,CC}FLAGS.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Cao jin <caoj.fnst@cn.fujitsu.com>

As kbuild document & commit 6588169d says: KBUILD_CFLAGS_MODULE is
used to add arch-specific options for $(CC). From commandline,
CFLAGS_MODULE shall be used.
Doesn't have any functional change, but just follow kbuild rules.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
CC: linux-hexagon@vger.kernel.org
Acked-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

As kbuild document & commit 6588169d says: KBUILD_CFLAGS_MODULE is
used to add arch-specific options for $(CC). From commandline,
CFLAGS_MODULE shall be used.
Doesn't have any functional change, but just follow kbuild rules.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
CC: Mark Salter <msalter@redhat.com>
CC: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
CC: linux-c6x-dev@linux-c6x.org
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

As kbuild document & commit 6588169d says: KBUILD_{C,LD}FLAGS_MODULE are
used to add arch-specific options for $(CC) and $(LD). From commandline,
{C,LD}FLAGS_MODULE shall be used.
Doesn't have any functional change, but just follow kbuild rules.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
CC: Russell King <linux@armlinux.org.uk>
CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

It has:
1. Move comments close to what it want to comment.
2. Comments cleanup & improvement.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

When compiling with `make CC=clang HOSTCC=clang`, I was seeing warnings
that clang did not recognize -fno-delete-null-pointer-checks for HOSTCC
targets.  These were added in commit 61163efa ("kbuild: LLVMLinux:
Add Kbuild support for building kernel with Clang").

Clang does not support -fno-delete-null-pointer-checks, so adding it to
HOSTCFLAGS if HOSTCC is clang does not make sense.

It's not clear why the other warnings were disabled, and just for
HOSTCFLAGS, but I can remove them, add -Werror to HOSTCFLAGS and compile
with clang just fine.
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The top Makefile is divided into some sections such as mixed targets,
config targets, build targets, etc.

When we build mixed targets, Kbuild just invokes submake to process
them one by one.  In this case, compiler-related variables like CC,
KBUILD_CFLAGS, etc. are unneeded.

Check what kind of targets we are building first, and parse variables
for building only when necessary.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The first "_all" occurrence around line 120 is only visible when
KBUILD_SRC is unset.

If O=... is specified, the working directory is relocated, then the
only second occurrence around line 193 is visible, that is not set
to PHONY.

Move the first one to an always visible place.  This clarifies "_all"
is our default target and it is always set to PHONY.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

Since commit 5e538790 ("sparc,sparc64: unify Makefile"), hdr-arch
and SRCARCH always match.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

This script does not need to create .version; it will be created by
scripts/link-vmlinux.sh later.  Clean-up the code slightly.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Since commit 1f2bfbd0 ("kbuild: link of vmlinux moved to a
script"), it is easy to increment .version without using a temporary
file .old_version.

I do not see anybody who creates the .tmp_version.  Probably it is a
left-over of commit 4e25d8bb ("[PATCH] kbuild: adjust .version
updating").  Just remove it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

<generated/compile.h> is created (or updated) when Kbuild descends
into the init/ directory.  In parallel building from a pristine
source tree, there is no guarantee <generated/compile.h> exists when
arch/hexagon/kernel/ptrace.c is compiled.

For hexagon architecture, we know UTS_MACHINE is a fixed string
"hexagon", so let's hard-code it, like many architectures do.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Richard Kuo <rkuo@codeaurora.org>

Pull x86 fixes from Thomas Gleixner:
 "This contains the following fixes and improvements:

   - Avoid dereferencing an unprotected VMA pointer in the fault signal
     generation code

   - Fix inline asm call constraints for GCC 4.4

   - Use existing register variable to retrieve the stack pointer
     instead of forcing the compiler to create another indirect access
     which results in excessive extra 'mov %rsp, %<dst>' instructions

   - Disable branch profiling for the memory encryption code to prevent
     an early boot crash

   - Fix a sparse warning caused by casting the __user annotation in
     __get_user_asm_u64() away

   - Fix an off by one error in the loop termination of the error patch
     in the x86 sysfs init code

   - Add missing CPU IDs to various Intel specific drivers to enable the
     functionality on recent hardware

   - More (init) constification in the numachip code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/asm: Use register variable to get stack pointer value
  x86/mm: Disable branch profiling in mem_encrypt.c
  x86/asm: Fix inline asm call constraints for GCC 4.4
  perf/x86/intel/uncore: Correct num_boxes for IIO and IRP
  perf/x86/intel/rapl: Add missing CPU IDs
  perf/x86/msr: Add missing CPU IDs
  perf/x86/intel/cstate: Add missing CPU IDs
  x86: Don't cast away the __user in __get_user_asm_u64()
  x86/sysfs: Fix off-by-one error in loop termination
  x86/mm: Fix fault error path using unsafe vma pointer
  x86/numachip: Add const and __initconst to numachip2_clockevent

Pull timer fixes from Thomas Gleixner:
 "This adds a new timer wheel function which is required for the
  conversion of the timer callback function from the 'unsigned long
  data' argument to 'struct timer_list *timer'. This conversion has two
  benefits:

   1) It makes struct timer_list smaller

   2) Many callers hand in a pointer to the timer or to the structure
      containing the timer, which happens via type casting both at setup
      and in the callback. This change gets rid of the typecasts.

  Once the conversion is complete, which is planned for 4.15, the old
  setup function and the intermediate typecast in the new setup function
  go away along with the data field in struct timer_list.

  Merging this now into mainline allows a smooth queueing of the actual
  conversion in the affected maintainer trees without creating
  dependencies"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  um/time: Fixup namespace collision
  timer: Prepare to change timer callback argument type

Pull smp/hotplug fixes from Thomas Gleixner:
 "This addresses the fallout of the new lockdep mechanism which covers
  completions in the CPU hotplug code.

  The lockdep splats are false positives, but there is no way to
  annotate that reliably. The solution is to split the completions for
  CPU up and down, which requires some reshuffling of the failure
  rollback handling as well"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp/hotplug: Hotplug state fail injection
  smp/hotplug: Differentiate the AP completion between up and down
  smp/hotplug: Differentiate the AP-work lockdep class between up and down
  smp/hotplug: Callback vs state-machine consistency
  smp/hotplug: Rewrite AP state machine core
  smp/hotplug: Allow external multi-instance rollback
  smp/hotplug: Add state diagram

Pull scheduler fixes from Thomas Gleixner:
 "The scheduler pull request comes with the following updates:

   - Prevent a divide by zero issue by validating the input value of
     sysctl_sched_time_avg

   - Make task state printing consistent all over the place and have
     explicit state characters for IDLE and PARKED so they wont be
     displayed as 'D' state which confuses tools"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/sysctl: Check user input value of sysctl_sched_time_avg
  sched/debug: Add explicit TASK_PARKED printing
  sched/debug: Ignore TASK_IDLE for SysRq-W
  sched/debug: Add explicit TASK_IDLE printing
  sched/tracing: Use common task-state helpers
  sched/tracing: Fix trace_sched_switch task-state printing
  sched/debug: Remove unused variable
  sched/debug: Convert TASK_state to hex
  sched/debug: Implement consistent task-state printing

Pull perf fixes from Thomas Gleixner:

 - Prevent a division by zero in the perf aux buffer handling

 - Sync kernel headers with perf tool headers

 - Fix a build failure in the syscalltbl code

 - Make the debug messages of perf report --call-graph work correctly

 - Make sure that all required perf files are in the MANIFEST for
   container builds

 - Fix the atrr.exclude kernel handling so it respects the
   perf_event_paranoid and the user permissions

 - Make perf test on s390x work correctly

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/aux: Only update ->aux_wakeup in non-overwrite mode
  perf test: Fix vmlinux failure on s390x part 2
  perf test: Fix vmlinux failure on s390x
  perf tools: Fix syscalltbl build failure
  perf report: Fix debug messages with --call-graph option
  perf evsel: Fix attr.exclude_kernel setting for default cycles:p
  tools include: Sync kernel ABI headers with tooling headers
  perf tools: Get all of tools/{arch,include}/ in the MANIFEST

Pull  locking fixes from Thomas Gleixner:
 "Two fixes for locking:

   - Plug a hole the pi_stat->owner serialization which was changed
     recently and failed to fixup two usage sites.

   - Prevent reordering of the rwsem_has_spinner() check vs the
     decrement of rwsem count in up_write() which causes a missed
     wakeup"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rwsem-xadd: Fix missed wakeup due to reordering of load
  futex: Fix pi_state->owner serialization

Pull irq fixes from Thomas Gleixner:

 - Add a missing NULL pointer check in free_irq()

 - Fix a memory leak/memory corruption in the generic irq chip

 - Add missing rcu annotations for radix tree access

 - Use ffs instead of fls when extracting data from a chip register in
   the MIPS GIC irq driver

 - Fix the unmasking of IPI interrupts in the MIPS GIC driver so they
   end up at the target CPU and not at CPU0

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irq/generic-chip: Don't replace domain's name
  irqdomain: Add __rcu annotations to radix tree accessors
  irqchip/mips-gic: Use effective affinity to unmask
  irqchip/mips-gic: Fix shifts to extract register fields
  genirq: Check __free_irq() return value for NULL

Pull objtool fixes from Thomas Gleixner:
 "Two small fixes for objtool:

   - Support frame pointer setup via 'lea (%rsp), %rbp' which was not
     yet supported and caused build warnings

   - Disable unreacahble warnings for GCC4.4 and older to avoid false
     positives caused by the compiler itself"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Support unoptimized frame pointer setup
  objtool: Skip unreachable warnings for GCC 4.4 and older

Pull mtd fixes from Boris Brezillon:

 - Fix partition alignment check in mtdcore.c

 - Fix a buffer overflow in the Atmel NAND driver

* tag 'mtd/fixes-for-4.14-rc3' of git://git.infradead.org/linux-mtd:
  mtd: nand: atmel: fix buffer overflow in atmel_pmecc_user
  mtd: Fix partition alignment check on multi-erasesize devices

Pull SCSI fixes from James Bottomley:
 "Eight mostly minor fixes for recently discovered issues in drivers"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: ILLEGAL REQUEST + ASC==27 => target failure
  scsi: aacraid: Add a small delay after IOP reset
  scsi: scsi_transport_fc: Also check for NOTPRESENT in fc_remote_port_add()
  scsi: scsi_transport_fc: set scsi_target_id upon rescan
  scsi: scsi_transport_iscsi: fix the issue that iscsi_if_rx doesn't parse nlmsg properly
  scsi: aacraid: error: testing array offset 'bus' after use
  scsi: lpfc: Don't return internal MBXERR_ERROR code from probe function
  scsi: aacraid: Fix 2T+ drives on SmartIOC-2000

Pull x86 platform drivers fix from Darren Hart:
 "Newly discovered species of fujitsu laptops break some assumptions
  about ACPI device pairings.

  fujitsu-laptop: Don't oops when FUJ02E3 is not present"

* tag 'platform-drivers-x86-v4.14-2' of git://git.infradead.org/linux-platform-drivers-x86:
  platform/x86: fujitsu-laptop: Don't oops when FUJ02E3 is not presnt