Support big-endian kernel by using endian-aware register access
functions.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Cc: ben.dooks@codethink.co.uk
Cc: hdegoede@redhat.com
Cc: laurent.pinchart+renesas@ideasonboard.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: maxime.ripard@free-electrons.com
Cc: viresh.kumar@linaro.org
Link: http://lkml.kernel.org/r/1427746633-9137-9-git-send-email-daniel.lezcano@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

The dw_apb_timer_of timer is using __raw_readl() to access the
timer register, which is causing issues when the system is
running in big endian mode. Fix this by using readl_relaxed()
which should account for the endian settings.

This fixes issues where the time jumps around in the dmesg
output due to returnling __le32 values.

For an example, these two console lines show time running
backwards:

[   49.882572] CPU1: failed to come online
[   43.282457] Brought up 1 CPUs
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Linux ARM Kernel <linux-arm-kernel@lists.infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: digetx@gmail.com
Cc: hdegoede@redhat.com
Cc: laurent.pinchart+renesas@ideasonboard.com
Cc: maxime.ripard@free-electrons.com
Cc: viresh.kumar@linaro.org
Link: http://lkml.kernel.org/r/1427746633-9137-10-git-send-email-daniel.lezcano@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

We have used CLOCK_EVT_MODE_PERIODIC instead of
CLOCK_EVT_FEAT_PERIODIC while defining features. Fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Cc: ben.dooks@codethink.co.uk
Cc: digetx@gmail.com
Cc: hdegoede@redhat.com
Cc: laurent.pinchart+renesas@ideasonboard.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: maxime.ripard@free-electrons.com
Link: http://lkml.kernel.org/r/1427746633-9137-11-git-send-email-daniel.lezcano@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull ARM SoC fixes from Olof Johansson:
 "The latest and greatest fixes for ARM platform code.  Worth pointing
  out are:

   - Lines-wise, largest is a PXA fix for dealing with interrupts on DT
     that was quite broken.  It's still newish code so while we could
     have held this off, it seemed appropriate to include now

   - Some GPIO fixes for OMAP platforms added a few lines.  This was
     also fixes for code recently added (this release).

   - Small OMAP timer fix to behave better with partially upstreamed
     platforms, which is quite welcome.

   - Allwinner fixes about operating point control, reducing
     overclocking in some cases for better stability.

  plus a handful of other smaller fixes across the map"

* tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm64: juno: Fix misleading name of UART reference clock
  ARM: dts: sunxi: Remove overclocked/overvoltaged OPP
  ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting
  ARM: socfpga: dts: fix spi1 interrupt
  ARM: dts: Fix gpio interrupts for dm816x
  ARM: dts: dra7: remove ti,hwmod property from pcie phy
  ARM: OMAP: dmtimer: disable pm runtime on remove
  ARM: OMAP: dmtimer: check for pm_runtime_get_sync() failure
  ARM: OMAP2+: Fix socbus family info for AM33xx devices
  ARM: dts: omap3: Add missing dmas for crypto
  ARM: dts: rockchip: disable gmac by default in rk3288.dtsi
  MAINTAINERS: add rockchip regexp to the ARM/Rockchip entry
  ARM: pxa: fix pxa interrupts handling in DT
  ARM: pxa: Fix typo in zeus.c
  ARM: sunxi: Have ARCH_SUNXI select RESET_CONTROLLER for clock driver usage

Merge tag 'sunxi-fixes-for-4.0' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into fixes

Allwinner fixes for 4.0

There's a few fixes to merge for 4.0, one to add a select in the machine
Kconfig option to fix a potential build failure, and two fixing cpufreq related
issues.

* tag 'sunxi-fixes-for-4.0' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  ARM: dts: sunxi: Remove overclocked/overvoltaged OPP
  ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting
  ARM: sunxi: Have ARCH_SUNXI select RESET_CONTROLLER for clock driver usage
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'fixes-v4.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes

Fixes for omaps for the -rc cycle:

- Fix a device tree based booting vs legacy booting regression for
  omap3 crypto hardware by adding the missing DMA channels.

- Fix /sys/bus/soc/devices/soc0/family for am33xx devices.

- Fix two timer issues that can cause hangs if the timer related
  hwmod data is missing like it often initially is for new SoCs.

- Remove pcie hwmods entry from dts as that causes runtime PM to
  fail for the PHYs.

- A paper bag type dts configuration fix for dm816x GPIO
  interrupts that I just noticed. This is most of the changes
  diffstat wise, but as it's a basic feature for connecting
  devices and things work otherwise, it should be fixed.

* tag 'fixes-v4.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: dts: Fix gpio interrupts for dm816x
  ARM: dts: dra7: remove ti,hwmod property from pcie phy
  ARM: OMAP: dmtimer: disable pm runtime on remove
  ARM: OMAP: dmtimer: check for pm_runtime_get_sync() failure
  ARM: OMAP2+: Fix socbus family info for AM33xx devices
  ARM: dts: omap3: Add missing dmas for crypto
Signed-off-by: Olof Johansson <olof@lixom.net>

Late fix for v4.0 on the SoCFPGA platform:
- Fix interrupt number for SPI1 interface

* tag 'socfpga_fix_for_v4.0_2' of git://git.rocketboards.org/linux-socfpga-next:
  ARM: socfpga: dts: fix spi1 interrupt
Signed-off-by: Olof Johansson <olof@lixom.net>

The UART reference clock speed is 7273.8 kHz, not 72738 kHz.

Dots aren't usually used in node names even though ePAPR permits
them.  However, this can easily be avoided by expressing the
frequency in Hz, not kHz.

This patch changes the name to refclk7273800hz, reflecting the
actual clock speed.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arm: pxa: fixes for v4.0-rc5

There are only 2 fixes, one for the zeus board about the regulator changes,
where a typo prevented the zeus board from having a working can regulator,
and one regression triggered by the interrupts IRQ shift of 16 affecting all
boards.

* tag 'fixes-for-v4.0-rc5' of https://github.com/rjarzmik/linux:
  ARM: pxa: fix pxa interrupts handling in DT
  ARM: pxa: Fix typo in zeus.c
Signed-off-by: Olof Johansson <olof@lixom.net>

Pull x86 fix from Ingo Molnar:
 "Fix x86 syscall exit code bug that resulted in spurious non-execution
  of TIF-driven user-return worklets, causing big trouble for things
  like KVM that rely on user notifiers for correctness of their vcpu
  model, causing crashes like double faults"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/asm/entry: Check for syscall exit work with IRQs disabled

Pull timer fixes from Ingo Molnar:
 "Two clocksource driver fixes, and an idle loop RCU warning fix"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/sun5i: Fix cpufreq interaction with sched_clock()
  clocksource/drivers: Fix various !CONFIG_HAS_IOMEM build errors
  timers/tick/broadcast-hrtimer: Fix suspicious RCU usage in idle loop

Pull scheduler fix from Ingo Molnar:
 "A single sched/rt corner case fix for RLIMIT_RTIME correctness"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix RLIMIT_RTTIME when PI-boosting to RT

Pull perf fix from Ingo Molnar:
 "A perf kernel side fix for a fuzzer triggered lockup"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix irq_work 'tail' recursion

Pull locking fix from Ingo Molnar:
 "A module unload lockdep race fix"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix the module unload key range freeing logic

Pull parsic fixes from Helge Deller:
 "One patch from Mikulas fixes a bug on parisc by artifically
  incrementing the counter in pmd_free when the kernel tries to free
  the preallocated pmd.

  Other than that we now prevent that syscalls gets added without
  incrementing __NR_Linux_syscalls and fix the initial pmd setup code
  if a default page size greater than 4k has been selected"

* 'parisc-4.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix pmd code to depend on PT_NLEVELS value, not on CONFIG_64BIT
  parisc: mm: don't count preallocated pmds
  parisc: Add compile-time check when adding new syscalls

Pull kvm ppc bugfixes from Marcelo Tosatti.

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: Book3S HV: Fix instruction emulation
  KVM: PPC: Book3S HV: Endian fix for accessing VPA yield count
  KVM: PPC: Book3S HV: Fix spinlock/mutex ordering issue in kvmppc_set_lpcr()

Pull ARC fixes from Vineet Gupta:
 "We found some issues with signal handling taking down the system.  I
  know its late, but these are important and all marked for stable.

  ARC signal handling related fixes uncovered during recent testing of
  NPTL tools"

* tag 'arc-4.0-fixes-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: signal handling robustify
  ARC: SA_SIGINFO ucontext regs off-by-one

Pull selinux bugfix from James Morris.

Fix broken return value.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  selinux: fix sel_write_enforce broken return value

Pull watchdog fixes from Wim Van Sebroeck:

 - mtk_wdt: signedness bug in mtk_wdt_start()

 - imgpdc: Fix NULL pointer dereference during probe and fix the default
   heartbeat

* git://www.linux-watchdog.org/linux-watchdog:
  watchdog: imgpdc: Fix default heartbeat
  watchdog: imgpdc: Fix probe NULL pointer dereference
  watchdog: mtk_wdt: signedness bug in mtk_wdt_start()

Pull sound fixes from Takashi Iwai:
 "Three trivial oneliner fixes for HD-audio.

  Two are device-specific quirks while one is a generic fix for recent
  Realtek codecs"

* tag 'sound-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - Add one more node in the EAPD supporting candidate list
  ALSA: hda_intel: apply the Seperate stream_tag for Sunrise Point
  ALSA: hda - Add dock support for Thinkpad T450s (17aa:5036)

It was a requirement in the legacy interface that drivers must
initialize ->mode field to 'CLOCK_EVT_MODE_UNUSED'. This field
isn't used anymore by the new interface and so should be only
checked for the legacy interface.

Probably it can be dropped as well as core doesn't rely on it
anymore, but lets keep it to support legacy interface.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/c6604fa1a77fe1fc8dcab87769857228fb1dadd5.1425037853.git.viresh.kumar@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

'enum clock_event_mode' is used for two purposes today:

 - to pass mode to the driver of clockevent device::set_mode().

 - for managing state of the device for clockevents core.

For supporting new modes/states we have moved away from the
legacy set_mode() callback to new per-mode/state callbacks. New
modes/states shouldn't be exposed to the legacy (now OBSOLOTE)
callbacks and so we shouldn't add new states to 'enum
clock_event_mode'.

Lets have separate enums for the two use cases mentioned above.
Keep using the earlier enum for legacy set_mode() callback and
mark it OBSOLETE. And add another enum to clearly specify the
possible states of a clockevent device.

This also renames the newly added per-mode callbacks to reflect
state changes.

We haven't got rid of 'mode' member of 'struct
clock_event_device' as it is used by some of the clockevent
drivers and it would automatically die down once we migrate
those drivers to the new interface. It ('mode') is only updated
now for the drivers using the legacy interface.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/b6b0143a8a57bd58352ad35e08c25424c879c0cb.1425037853.git.viresh.kumar@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Upcoming patch will redefine possible states of a clockevent
device. The RESUME mode is a special case only for tick's
clockevent devices. In future it can be replaced by ->resume()
callback already available for clockevent devices.

Lets handle it separately so that clockevents_set_mode() only
handles states valid across all devices. This also renames
set_mode_resume() to tick_resume() to make it more explicit.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/c1b0112410870f49e7bf06958e1483eac6c15e20.1425037853.git.viresh.kumar@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Because it was the only clock for which we didn't have a _ns()
accessor yet.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Add the NMI safe CLOCK_MONOTONIC_RAW accessor..
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.562746929@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

In preparation for more tk_fast instances, remove all hard-coded
tk_fast_mono references.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.484279927@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Introduce tkr_raw and make use of it.

  base_raw -> tkr_raw.base
  clock->{mult,shift} -> tkr_raw.{mult.shift}

Kill timekeeping_get_ns_raw() in favour of
timekeeping_get_ns(&tkr_raw), this removes all mono_raw special
casing.

Duplicate the updates to tkr_mono.cycle_last into tkr_raw.cycle_last,
both need the same value.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.422589590@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

In preparation of adding another tkr field, rename this one to
tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base,
since the structure is not specific to CLOCK_MONOTONIC and the mono
name got added to the tk_read_base instance.

Lots of trivial churn.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

The IMG PDC watchdog driver heartbeat module parameter has no default so
it is initialised to zero. This results in the following warning during
probe:

imgpdc-wdt 2006000.wdt: Initial timeout out of range! setting max timeout

The module parameter description implies that the default value should
be PDC_WDT_DEF_TIMEOUT, which isn't yet used, so initialise it to that.

Also tweak the heartbeat module parameter description for consistency.

Fixes: 93937669 ("watchdog: ImgTec PDC Watchdog Timer Driver")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Cc: Jude Abraham <Jude.Abraham@imgtec.com>
Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The IMG PDC watchdog probe function calls pdc_wdt_stop() prior to
watchdog_set_drvdata(), causing a NULL pointer dereference when
pdc_wdt_stop() retrieves the struct pdc_wdt_dev pointer using
watchdog_get_drvdata() and reads the register base address through it.

Fix by moving the watchdog_set_drvdata() call earlier, to where various
other pdc_wdt->wdt_dev fields are initialised.

Fixes: 93937669 ("watchdog: ImgTec PDC Watchdog Timer Driver")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Cc: Jude Abraham <Jude.Abraham@imgtec.com>
Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

"ret" should be signed for the error handling to work correctly.  This
doesn't matter much in real life since mtk_wdt_set_timeout() always
succeeds.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Trivial cleanups, to improve the readability of the generic sched_clock() code:

 - Improve and standardize comments
 - Standardize the coding style
 - Use vertical spacing where appropriate
 - etc.

No code changed:

  md5:
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.before.asm
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.after.asm

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Currently it is possible for an NMI (or FIQ on ARM) to come in
and read sched_clock() whilst update_sched_clock() has locked
the seqcount for writing. This results in the NMI handler
locking up when it calls raw_read_seqcount_begin().

This patch fixes the NMI safety issues by providing banked clock
data. This is a similar approach to the one used in Thomas
Gleixner's 4396e058("timekeeping: Provide fast and NMI safe
access to CLOCK_MONOTONIC").
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-6-git-send-email-john.stultz@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Currently update_sched_clock() is marked as notrace but this
function is not called by ftrace. This is trivially fixed by
removing the mark up.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-5-git-send-email-john.stultz@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Currently cd.read_data.suspended is read by the hotpath function
sched_clock(). This variable need not be accessed on the
hotpath. In fact, once it is removed, we can remove the
conditional branches from sched_clock() and install a dummy
read_sched_clock function to suspend the clock.

The new master copy of the function pointer
(actual_read_sched_clock) is introduced and is used for all
reads of the clock hardware except those within sched_clock
itself.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-4-git-send-email-john.stultz@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Currently sched_clock(), a very hot code path, is not optimized
to minimise its cache profile. In particular:

  1. cd is not ____cacheline_aligned,

  2. struct clock_data does not distinguish between hotpath and
     coldpath data, reducing locality of reference in the hotpath,

  3. Some hotpath data is missing from struct clock_data and is marked
     __read_mostly (which more or less guarantees it will not share a
     cache line with cd).

This patch corrects these problems by extracting all hotpath
data into a separate structure and using ____cacheline_aligned
to ensure the hotpath uses a single (64 byte) cache line.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-3-git-send-email-john.stultz@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

Currently the scope of the raw_write_seqcount_begin/end() in
sched_clock_register() far exceeds the scope of the read section
in sched_clock(). This gives the impression of safety during
cursory review but achieves little.

Note that this is likely to be a latent issue at present because
sched_clock_register() is typically called before we enable
interrupts, however the issue does risk bugs being needlessly
introduced as the code evolves.

This patch fixes the problem by increasing the scope of the read
locking performed by sched_clock() to cover all data modified by
sched_clock_register.

We also improve clarity by moving writes to struct clock_data
that do not impact sched_clock() outside of the critical
section.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
[ Reworked it slightly to apply to tip/timers/core]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-2-git-send-email-john.stultz@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>