The case addressed by commit 5ef499cd571c (cpuidle: menu: Handle
stopped tick more aggressively) in the stopped tick case is present
when the tick has not been stopped yet too.  Namely, if only two CPU
idle states, shallow state A with target residency significantly
below the tick boundary and deep state B with target residency
significantly above it, are available and the predicted idle
duration is above the tick boundary, but below the target residency
of state B, state A will be selected and the CPU may spend indefinite
amount of time in it, which is not quite energy-efficient.

However, if the tick has not been stopped yet and the governor is
about to select a shallow idle state for the CPU even though the idle
duration predicted by it is above the tick boundary, it should be
fine to wake up the CPU early, so the tick can be retained then and
the governor will have a chance to select a deeper state when it runs
next time.

[Note that when this really happens, it will make the idle duration
 predictor believe that the CPU might be idle longer than predicted,
 which will make it more likely to predict longer idle durations going
 forward, but that will also cause deeper idle states to be selected
 going forward, on average, which is what's needed here.]

Fixes: 87c9fe6ee495 (cpuidle: menu: Avoid selecting shallow states with stopped tick)
Reported-by: Leo Yan <leo.yan@linaro.org>
Cc: 4.17+ <stable@vger.kernel.org> # 4.17+: 5ef499cd571c (cpuidle: menu: Handle ...)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull more power management updates from Rafael Wysocki:
 "These fix the main idle loop and the menu cpuidle governor, clean up
  the latter, fix a mistake in the PCI bus type's support for system
  suspend and resume, fix the ondemand and conservative cpufreq
  governors, address a build issue in the system wakeup framework and
  make the ACPI C-states desciptions less confusing.

  Specifics:

   - Make the idle loop handle stopped scheduler tick correctly (Rafael
     Wysocki).

   - Prevent the menu cpuidle governor from letting CPUs spend too much
     time in shallow idle states when it is invoked with scheduler tick
     stopped and clean it up somewhat (Rafael Wysocki).

   - Avoid invoking the platform firmware to make the platform enter the
     ACPI S3 sleep state with suspended PCIe root ports which may
     confuse the firmware and cause it to crash (Rafael Wysocki).

   - Fix sysfs-related race in the ondemand and conservative cpufreq
     governors which may cause the system to crash if the governor
     module is removed during an update of CPU frequency limits (Henry
     Willard).

   - Select SRCU when building the system wakeup framework to avoid a
     build issue in it (zhangyi).

   - Make the descriptions of ACPI C-states vendor-neutral to avoid
     confusion (Prarit Bhargava)"

* tag 'pm-4.19-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: menu: Handle stopped tick more aggressively
  sched: idle: Avoid retaining the tick when it has been stopped
  PCI / ACPI / PM: Resume all bridges on suspend-to-RAM
  cpuidle: menu: Update stale polling override comment
  cpufreq: governor: Avoid accessing invalid governor_data
  x86/ACPI/cstate: Make APCI C1 FFH MWAIT C-state description vendor-neutral
  cpuidle: menu: Fix white space
  PM / sleep: wakeup: Fix build error caused by missing SRCU support

Commit 87c9fe6ee495 (cpuidle: menu: Avoid selecting shallow states
with stopped tick) missed the case when the target residencies of
deep idle states of CPUs are above the tick boundary which may cause
the CPU to get stuck in a shallow idle state for a long time.

Say there are two CPU idle states available: one shallow, with the
target residency much below the tick boundary and one deep, with
the target residency significantly above the tick boundary.  In
that case, if the tick has been stopped already and the expected
next timer event is relatively far in the future, the governor will
assume the idle duration to be equal to TICK_USEC and it will select
the idle state for the CPU accordingly.  However, that will cause the
shallow state to be selected even though it would have been more
energy-efficient to select the deep one.

To address this issue, modify the governor to always use the time
till the closest timer event instead of the predicted idle duration
if the latter is less than the tick period length and the tick has
been stopped already.  Also make it extend the search for a matching
idle state if the tick is stopped to avoid settling on a shallow
state if deep states with target residencies above the tick period
length are available.

In addition, make it always indicate that the tick should be stopped
if it has been stopped already for consistency.

Fixes: 87c9fe6ee495 (cpuidle: menu: Avoid selecting shallow states with stopped tick)
Reported-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: 4.17+ <stable@vger.kernel.org> # 4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - A fix for a bug in our page table fragment allocator, where a page
     table page could be freed and reallocated for something else while
     still in use, leading to memory corruption etc. The fix reuses
     pt_mm in struct page (x86 only) for a powerpc only refcount.

   - Fixes to our pkey support. Several are user-visible changes, but
     bring us in to line with x86 behaviour and/or fix outright bugs.
     Thanks to Florian Weimer for reporting many of these.

   - A series to improve the hvc driver & related OPAL console code,
     which have been seen to cause hardlockups at times. The hvc driver
     changes in particular have been in linux-next for ~month.

   - Increase our MAX_PHYSMEM_BITS to 128TB when SPARSEMEM_VMEMMAP=y.

   - Remove Power8 DD1 and Power9 DD1 support, neither chip should be in
     use anywhere other than as a paper weight.

   - An optimised memcmp implementation using Power7-or-later VMX
     instructions

   - Support for barrier_nospec on some NXP CPUs.

   - Support for flushing the count cache on context switch on some IBM
     CPUs (controlled by firmware), as a Spectre v2 mitigation.

   - A series to enhance the information we print on unhandled signals
     to bring it into line with other arches, including showing the
     offending VMA and dumping the instructions around the fault.

  Thanks to: Aaro Koskinen, Akshay Adiga, Alastair D'Silva, Alexey
  Kardashevskiy, Alexey Spirkov, Alistair Popple, Andrew Donnellan,
  Aneesh Kumar K.V, Anju T Sudhakar, Arnd Bergmann, Bartosz Golaszewski,
  Benjamin Herrenschmidt, Bharat Bhushan, Bjoern Noetel, Boqun Feng,
  Breno Leitao, Bryant G. Ly, Camelia Groza, Christophe Leroy, Christoph
  Hellwig, Cyril Bur, Dan Carpenter, Daniel Klamt, Darren Stevens, Dave
  Young, David Gibson, Diana Craciun, Finn Thain, Florian Weimer,
  Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven, Geoff Levand,
  Guenter Roeck, Gustavo Romero, Haren Myneni, Hari Bathini, Joel
  Stanley, Jonathan Neuschäfer, Kees Cook, Madhavan Srinivasan, Mahesh
  Salgaonkar, Markus Elfring, Mathieu Malaterre, Mauro S. M. Rodrigues,
  Michael Hanselmann, Michael Neuling, Michael Schmitz, Mukesh Ojha,
  Murilo Opsfelder Araujo, Nicholas Piggin, Parth Y Shah, Paul
  Mackerras, Paul Menzel, Ram Pai, Randy Dunlap, Rashmica Gupta, Reza
  Arbab, Rodrigo R. Galvao, Russell Currey, Sam Bobroff, Scott Wood,
  Shilpasri G Bhat, Simon Guo, Souptick Joarder, Stan Johnson, Thiago
  Jung Bauermann, Tyrel Datwyler, Vaibhav Jain, Vasant Hegde, Venkat
  Rao, zhong jiang"

* tag 'powerpc-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (234 commits)
  powerpc/mm/book3s/radix: Add mapping statistics
  powerpc/uaccess: Enable get_user(u64, *p) on 32-bit
  powerpc/mm/hash: Remove unnecessary do { } while(0) loop
  powerpc/64s: move machine check SLB flushing to mm/slb.c
  powerpc/powernv/idle: Fix build error
  powerpc/mm/tlbflush: update the mmu_gather page size while iterating address range
  powerpc/mm: remove warning about ‘type’ being set
  powerpc/32: Include setup.h header file to fix warnings
  powerpc: Move `path` variable inside DEBUG_PROM
  powerpc/powermac: Make some functions static
  powerpc/powermac: Remove variable x that's never read
  cxl: remove a dead branch
  powerpc/powermac: Add missing include of header pmac.h
  powerpc/kexec: Use common error handling code in setup_new_fdt()
  powerpc/xmon: Add address lookup for percpu symbols
  powerpc/mm: remove huge_pte_offset_and_shift() prototype
  powerpc/lib: Use patch_site to patch copy_32 functions once cache is enabled
  powerpc/pseries: Fix endianness while restoring of r3 in MCE handler.
  powerpc/fadump: merge adjacent memory ranges to reduce PT_LOAD segements
  powerpc/fadump: handle crash memory ranges array index overflow
  ...

The comment to explain why the menu governor uses idle state 1
instead of idle state 0 as the first one sometimes is stale (among
other things it mentions a user setting not present any more),
so update it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix some damaged white space in menu_select().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Export pnv_idle_states and nr_pnv_idle_states so that its accessible to
cpuidle driver. Use properties from pnv_idle_states structure for powernv
cpuidle_init.

Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

It's perfectly fine to have multiple cpuidle driver compiled in the
build configuration. However, it's not good to throw error on driver
registration failure if some other driver is already initialised and
assigned. In such cases, __cpuidle_register_driver returns -EBUSY and
we can check for such error before throwing the error.

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

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Support for split PMD page table lock on 64-bit Book3S (Power8/9).

   - Add support for HAVE_RELIABLE_STACKTRACE, so we properly support
     live patching again.

   - Add support for patching barrier_nospec in copy_from_user() and
     syscall entry.

   - A couple of fixes for our data breakpoints on Book3S.

   - A series from Nick optimising TLB/mm handling with the Radix MMU.

   - Numerous small cleanups to squash sparse/gcc warnings from Mathieu
     Malaterre.

   - Several series optimising various parts of the 32-bit code from
     Christophe Leroy.

   - Removal of support for two old machines, "SBC834xE" and "C2K"
     ("GEFanuc,C2K"), which is why the diffstat has so many deletions.

  And many other small improvements & fixes.

  There's a few out-of-area changes. Some minor ftrace changes OK'ed by
  Steve, and a fix to our powernv cpuidle driver. Then there's a series
  touching mm, x86 and fs/proc/task_mmu.c, which cleans up some details
  around pkey support. It was ack'ed/reviewed by Ingo & Dave and has
  been in next for several weeks.

  Thanks to: Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Al
  Viro, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Arnd
  Bergmann, Balbir Singh, Cédric Le Goater, Christophe Leroy, Christophe
  Lombard, Colin Ian King, Dave Hansen, Fabio Estevam, Finn Thain,
  Frederic Barrat, Gautham R. Shenoy, Haren Myneni, Hari Bathini, Ingo
  Molnar, Jonathan Neuschäfer, Josh Poimboeuf, Kamalesh Babulal,
  Madhavan Srinivasan, Mahesh Salgaonkar, Mark Greer, Mathieu Malaterre,
  Matthew Wilcox, Michael Neuling, Michal Suchanek, Naveen N. Rao,
  Nicholas Piggin, Nicolai Stange, Olof Johansson, Paul Gortmaker, Paul
  Mackerras, Peter Rosin, Pridhiviraj Paidipeddi, Ram Pai, Rashmica
  Gupta, Ravi Bangoria, Russell Currey, Sam Bobroff, Samuel
  Mendoza-Jonas, Segher Boessenkool, Shilpasri G Bhat, Simon Guo,
  Souptick Joarder, Stewart Smith, Thiago Jung Bauermann, Torsten Duwe,
  Vaibhav Jain, Wei Yongjun, Wolfram Sang, Yisheng Xie, YueHaibing"

* tag 'powerpc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (251 commits)
  powerpc/64s/radix: Fix missing ptesync in flush_cache_vmap
  cpuidle: powernv: Fix promotion from snooze if next state disabled
  powerpc: fix build failure by disabling attribute-alias warning in pci_32
  ocxl: Fix missing unlock on error in afu_ioctl_enable_p9_wait()
  powerpc-opal: fix spelling mistake "Uniterrupted" -> "Uninterrupted"
  powerpc: fix spelling mistake: "Usupported" -> "Unsupported"
  powerpc/pkeys: Detach execute_only key on !PROT_EXEC
  powerpc/powernv: copy/paste - Mask SO bit in CR
  powerpc: Remove core support for Marvell mv64x60 hostbridges
  powerpc/boot: Remove core support for Marvell mv64x60 hostbridges
  powerpc/boot: Remove support for Marvell mv64x60 i2c controller
  powerpc/boot: Remove support for Marvell MPSC serial controller
  powerpc/embedded6xx: Remove C2K board support
  powerpc/lib: optimise PPC32 memcmp
  powerpc/lib: optimise 32 bits __clear_user()
  powerpc/time: inline arch_vtime_task_switch()
  powerpc/Makefile: set -mcpu=860 flag for the 8xx
  powerpc: Implement csum_ipv6_magic in assembly
  powerpc/32: Optimise __csum_partial()
  powerpc/lib: Adjust .balign inside string functions for PPC32
  ...

The commit 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of
snooze to deeper idle state") introduced a timeout for the snooze idle
state so that it could be eventually be promoted to a deeper idle
state. The snooze timeout value is static and set to the target
residency of the next idle state, which would train the cpuidle
governor to pick the next idle state eventually.

The unfortunate side-effect of this is that if the next idle state(s)
is disabled, the CPU will forever remain in snooze, despite the fact
that the system is completely idle, and other deeper idle states are
available.

This patch fixes the issue by dynamically setting the snooze timeout
to the target residency of the next enabled state on the device.

Before Patch:
  POWER8 : Only nap disabled.
  $ cpupower monitor sleep 30
  sleep took 30.01297 seconds and exited with status 0
                |Idle_Stats
  PKG |CORE|CPU | snoo | Nap  | Fast
     0|   8|   0| 96.41|  0.00|  0.00
     0|   8|   1| 96.43|  0.00|  0.00
     0|   8|   2| 96.47|  0.00|  0.00
     0|   8|   3| 96.35|  0.00|  0.00
     0|   8|   4| 96.37|  0.00|  0.00
     0|   8|   5| 96.37|  0.00|  0.00
     0|   8|   6| 96.47|  0.00|  0.00
     0|   8|   7| 96.47|  0.00|  0.00

  POWER9: Shallow states (stop0lite, stop1lite, stop2lite, stop0, stop1,
  stop2) disabled:
  $ cpupower monitor sleep 30
  sleep took 30.05033 seconds and exited with status 0
                |Idle_Stats
  PKG |CORE|CPU | snoo | stop | stop | stop | stop | stop | stop | stop | stop
     0|  16|   0| 89.79|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00
     0|  16|   1| 90.12|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00
     0|  16|   2| 90.21|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00
     0|  16|   3| 90.29|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00

After Patch:
  POWER8 : Only nap disabled.
  $ cpupower monitor sleep 30
  sleep took 30.01200 seconds and exited with status 0
                |Idle_Stats
  PKG |CORE|CPU | snoo | Nap  | Fast
     0|   8|   0| 16.58|  0.00| 77.21
     0|   8|   1| 18.42|  0.00| 75.38
     0|   8|   2|  4.70|  0.00| 94.09
     0|   8|   3| 17.06|  0.00| 81.73
     0|   8|   4|  3.06|  0.00| 95.73
     0|   8|   5|  7.00|  0.00| 96.80
     0|   8|   6|  1.00|  0.00| 98.79
     0|   8|   7|  5.62|  0.00| 94.17

  POWER9: Shallow states (stop0lite, stop1lite, stop2lite, stop0, stop1,
  stop2) disabled:

  $ cpupower monitor sleep 30
  sleep took 30.02110 seconds and exited with status 0
                |Idle_Stats
  PKG |CORE|CPU | snoo | stop | stop | stop | stop | stop | stop | stop | stop
     0|   0|   0|  0.69|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  9.39| 89.70
     0|   0|   1|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.05| 93.21
     0|   0|   2|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00| 89.93
     0|   0|   3|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00|  0.00| 93.26

Fixes: 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>