Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

To be able to predict the sleep duration for a CPU entering idle, it
is essential to know the expiration time of the next timer.  Both the
teo and the menu cpuidle governors already use this information for
CPU idle state selection.

Moving forward, a similar prediction needs to be made for a group of
idle CPUs rather than for a single one and the following changes
implement a new genpd governor for that purpose.

In order to support that feature, add a new function called
tick_nohz_get_next_hrtimer() that will return the next hrtimer
expiration time of a given CPU to be invoked after deciding
whether or not to stop the scheduler tick on that CPU.

Make the cpuidle core call tick_nohz_get_next_hrtimer() right
before invoking the ->enter() callback provided by the cpuidle
driver for the given state and store its return value in the
per-CPU struct cpuidle_device, so as to make it available to code
outside of cpuidle.

Note that at the point when cpuidle calls tick_nohz_get_next_hrtimer(),
the governor's ->select() callback has already returned and indicated
whether or not the tick should be stopped, so in fact the value
returned by tick_nohz_get_next_hrtimer() always is the next hrtimer
expiration time for the given CPU, possibly including the tick (if
it hasn't been stopped).

Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Since commit 45f1ff59e27c ("cpuidle: Return nohz hint from
cpuidle_select()") Exynos CPUidle driver stopped entering C1 (AFTR) mode
on Exynos4412-based Trats2 board.

Further analysis revealed that the CPUidle framework changed the way
it handles predicted timer ticks and reported target residency for the
given idle states. As a result, the C1 (AFTR) state was not chosen
anymore on completely idle device. The main issue was to high target
residency value. The similar C1 (AFTR) state for 'coupled' CPUidle
version used 10 times lower value for the target residency, despite
the fact that it is the same state from the hardware perspective.

The 100000us value for standard C1 (AFTR) mode is there from the begining
of the support for this idle state, added by the commit 67173ca492ab
("ARM: EXYNOS: Add support AFTR mode on EXYNOS4210"). That commit doesn't
give any reason for it, instead it looks like it was blindly copied from
the WFI/IDLE state of the same driver that time. That time, that value
was probably not really used by the framework for any critical decision,
so it didn't matter that much.

Now it turned out to be an issue, so unify the target residency with the
'coupled' version, as it seems to better match the real use case values
and restores the operation of the Exynos CPUidle driver on the idle
device.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit 61cb5758d3c4 ("cpuidle: Add cpuidle.governor= command
line parameter") new cpuidle governors are not added to the list
of available governors, so governor selection via sysfs doesn't
work as expected (even though it is rarely used anyway).

Fix that by making cpuidle_register_governor() add new governors to
cpuidle_governors again.

Fixes: 61cb5758d3c4 ("cpuidle: Add cpuidle.governor= command line parameter")
Reported-by: Kees Cook <keescook@chromium.org>
Cc: 5.0+ <stable@vger.kernel.org> # 5.0+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The variance computation in get_typical_interval() may overflow if
the square of the value of diff exceeds the maximum for the int64_t
data type value which basically is the case when it is of the order
of UINT_MAX.

However, data points so far in the future don't matter for idle
state selection anyway, so change the initial threshold value in
get_typical_interval() to INT_MAX which will cause more "outlying"
data points to be discarded without affecting the selection result.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently, the DT of the idle states will be parsed first whether it's
compatible or not. This could cause a warning message that comes from if
the CPU doesn't support identical idle states. E.g. Tegra186 can run
with 2 Cortex-A57 and 2 Denver cores with different idle states on
different types of these cores.

So fix it by checking the match node earlier, then it can make sure it
only goes through the idle states that the CPU supported.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The default time is declared in units of microsecnds,
but is used as nanoseconds, resulting in significant
accounting errors for idle state 0 time when all idle
states deeper than 0 are disabled.

Under these unusual conditions, we don't really care
about the poll time limit anyhow.

Fixes: 800fb34a99ce ("cpuidle: poll_state: Disregard disable idle states")
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The venerable menu governor does some things that are quite
questionable in my view.

First, it includes timer wakeups in the pattern detection data and
mixes them up with wakeups from other sources which in some cases
causes it to expect what essentially would be a timer wakeup in a
time frame in which no timer wakeups are possible (because it knows
the time until the next timer event and that is later than the
expected wakeup time).

Second, it uses the extra exit latency limit based on the predicted
idle duration and depending on the number of tasks waiting on I/O,
even though those tasks may run on a different CPU when they are
woken up.  Moreover, the time ranges used by it for the sleep length
correction factors depend on whether or not there are tasks waiting
on I/O, which again doesn't imply anything in particular, and they
are not correlated to the list of available idle states in any way
whatever.

Also, the pattern detection code in menu may end up considering
values that are too large to matter at all, in which cases running
it is a waste of time.

A major rework of the menu governor would be required to address
these issues and the performance of at least some workloads (tuned
specifically to the current behavior of the menu governor) is likely
to suffer from that.  It is thus better to introduce an entirely new
governor without them and let everybody use the governor that works
better with their actual workloads.

The new governor introduced here, the timer events oriented (TEO)
governor, uses the same basic strategy as menu: it always tries to
find the deepest idle state that can be used in the given conditions.
However, it applies a different approach to that problem.

First, it doesn't use "correction factors" for the time till the
closest timer, but instead it tries to correlate the measured idle
duration values with the available idle states and use that
information to pick up the idle state that is most likely to "match"
the upcoming CPU idle interval.

Second, it doesn't take the number of "I/O waiters" into account at
all and the pattern detection code in it avoids taking timer wakeups
into account.  It also only uses idle duration values less than the
current time till the closest timer (with the tick excluded) for that
purpose.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Mitigations for Spectre v2 on some Freescale (NXP) CPUs.

   - A large series adding support for pass-through of Nvidia V100 GPUs
     to guests on Power9.

   - Another large series to enable hardware assistance for TLB table
     walk on MPC8xx CPUs.

   - Some preparatory changes to our DMA code, to make way for further
     cleanups from Christoph.

   - Several fixes for our Transactional Memory handling discovered by
     fuzzing the signal return path.

   - Support for generating our system call table(s) from a text file
     like other architectures.

   - A fix to our page fault handler so that instead of generating a
     WARN_ON_ONCE, user accesses of kernel addresses instead print a
     ratelimited and appropriately scary warning.

   - A cosmetic change to make our unhandled page fault messages more
     similar to other arches and also more compact and informative.

   - Freescale updates from Scott:
       "Highlights include elimination of legacy clock bindings use from
        dts files, an 83xx watchdog handler, fixes to old dts interrupt
        errors, and some minor cleanup."

  And many clean-ups, reworks and minor fixes etc.

  Thanks to: Alexandre Belloni, Alexey Kardashevskiy, Andrew Donnellan,
  Aneesh Kumar K.V, Arnd Bergmann, Benjamin Herrenschmidt, Breno Leitao,
  Christian Lamparter, Christophe Leroy, Christoph Hellwig, Daniel
  Axtens, Darren Stevens, David Gibson, Diana Craciun, Dmitry V. Levin,
  Firoz Khan, Geert Uytterhoeven, Greg Kurz, Gustavo Romero, Hari
  Bathini, Joel Stanley, Kees Cook, Madhavan Srinivasan, Mahesh
  Salgaonkar, Markus Elfring, Mathieu Malaterre, Michal Suchánek, Naveen
  N. Rao, Nick Desaulniers, Oliver O'Halloran, Paul Mackerras, Ram Pai,
  Ravi Bangoria, Rob Herring, Russell Currey, Sabyasachi Gupta, Sam
  Bobroff, Satheesh Rajendran, Scott Wood, Segher Boessenkool, Stephen
  Rothwell, Tang Yuantian, Thiago Jung Bauermann, Yangtao Li, Yuantian
  Tang, Yue Haibing"

* tag 'powerpc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (201 commits)
  Revert "powerpc/fsl_pci: simplify fsl_pci_dma_set_mask"
  powerpc/zImage: Also check for stdout-path
  powerpc: Fix HMIs on big-endian with CONFIG_RELOCATABLE=y
  macintosh: Use of_node_name_{eq, prefix} for node name comparisons
  ide: Use of_node_name_eq for node name comparisons
  powerpc: Use of_node_name_eq for node name comparisons
  powerpc/pseries/pmem: Convert to %pOFn instead of device_node.name
  powerpc/mm: Remove very old comment in hash-4k.h
  powerpc/pseries: Fix node leak in update_lmb_associativity_index()
  powerpc/configs/85xx: Enable CONFIG_DEBUG_KERNEL
  powerpc/dts/fsl: Fix dtc-flagged interrupt errors
  clk: qoriq: add more compatibles strings
  powerpc/fsl: Use new clockgen binding
  powerpc/83xx: handle machine check caused by watchdog timer
  powerpc/fsl-rio: fix spelling mistake "reserverd" -> "reserved"
  powerpc/fsl_pci: simplify fsl_pci_dma_set_mask
  arch/powerpc/fsl_rmu: Use dma_zalloc_coherent
  vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver
  vfio_pci: Allow regions to add own capabilities
  vfio_pci: Allow mapping extra regions
  ...