Commit Graph

1287 Commits

Author SHA1 Message Date
Linus Torvalds
814a2bf957 Merge branch 'akpm' (patches from Andrew)
Merge second patch-bomb from Andrew Morton:

 - a couple of hotfixes

 - the rest of MM

 - a new timer slack control in procfs

 - a couple of procfs fixes

 - a few misc things

 - some printk tweaks

 - lib/ updates, notably to radix-tree.

 - add my and Nick Piggin's old userspace radix-tree test harness to
   tools/testing/radix-tree/.  Matthew said it was a godsend during the
   radix-tree work he did.

 - a few code-size improvements, switching to __always_inline where gcc
   screwed up.

 - partially implement character sets in sscanf

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits)
  sscanf: implement basic character sets
  lib/bug.c: use common WARN helper
  param: convert some "on"/"off" users to strtobool
  lib: add "on"/"off" support to kstrtobool
  lib: update single-char callers of strtobool()
  lib: move strtobool() to kstrtobool()
  include/linux/unaligned: force inlining of byteswap operations
  include/uapi/linux/byteorder, swab: force inlining of some byteswap operations
  include/asm-generic/atomic-long.h: force inlining of some atomic_long operations
  usb: common: convert to use match_string() helper
  ide: hpt366: convert to use match_string() helper
  ata: hpt366: convert to use match_string() helper
  power: ab8500: convert to use match_string() helper
  power: charger_manager: convert to use match_string() helper
  drm/edid: convert to use match_string() helper
  pinctrl: convert to use match_string() helper
  device property: convert to use match_string() helper
  lib/string: introduce match_string() helper
  radix-tree tests: add test for radix_tree_iter_next
  radix-tree tests: add regression3 test
  ...
2016-03-18 19:26:54 -07:00
Linus Torvalds
49dc2b7173 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  drivers/rtc: broken link fix
  drm/i915 Fix typos in i915_gem_fence.c
  Docs: fix missing word in REPORTING-BUGS
  lib+mm: fix few spelling mistakes
  MAINTAINERS: add git URL for APM driver
  treewide: Fix typo in printk
2016-03-17 21:38:27 -07:00
Kees Cook
4cc7ecb7f2 param: convert some "on"/"off" users to strtobool
This changes several users of manual "on"/"off" parsing to use
strtobool.

Some side-effects:
- these uses will now parse y/n/1/0 meaningfully too
- the early_param uses will now bubble up parse errors

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Joe Perches <joe@perches.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steve French <sfrench@samba.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
John Stultz
da8b44d5a9 timer: convert timer_slack_ns from unsigned long to u64
This patchset introduces a /proc/<pid>/timerslack_ns interface which
would allow controlling processes to be able to set the timerslack value
on other processes in order to save power by avoiding wakeups (Something
Android currently does via out-of-tree patches).

The first patch tries to fix the internal timer_slack_ns usage which was
defined as a long, which limits the slack range to ~4 seconds on 32bit
systems.  It converts it to a u64, which provides the same basically
unlimited slack (500 years) on both 32bit and 64bit machines.

The second patch introduces the /proc/<pid>/timerslack_ns interface
which allows the full 64bit slack range for a task to be read or set on
both 32bit and 64bit machines.

With these two patches, on a 32bit machine, after setting the slack on
bash to 10 seconds:

$ time sleep 1

real    0m10.747s
user    0m0.001s
sys     0m0.005s

The first patch is a little ugly, since I had to chase the slack delta
arguments through a number of functions converting them to u64s.  Let me
know if it makes sense to break that up more or not.

Other than that things are fairly straightforward.

This patch (of 2):

The timer_slack_ns value in the task struct is currently a unsigned
long.  This means that on 32bit applications, the maximum slack is just
over 4 seconds.  However, on 64bit machines, its much much larger (~500
years).

This disparity could make application development a little (as well as
the default_slack) to a u64.  This means both 32bit and 64bit systems
have the same effective internal slack range.

Now the existing ABI via PR_GET_TIMERSLACK and PR_SET_TIMERSLACK specify
the interface as a unsigned long, so we preserve that limitation on
32bit systems, where SET_TIMERSLACK can only set the slack to a unsigned
long value, and GET_TIMERSLACK will return ULONG_MAX if the slack is
actually larger then what can be stored by an unsigned long.

This patch also modifies hrtimer functions which specified the slack
delta as a unsigned long.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Linus Torvalds
bb7aeae3d6 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security layer updates from James Morris:
 "There are a bunch of fixes to the TPM, IMA, and Keys code, with minor
  fixes scattered across the subsystem.

  IMA now requires signed policy, and that policy is also now measured
  and appraised"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (67 commits)
  X.509: Make algo identifiers text instead of enum
  akcipher: Move the RSA DER encoding check to the crypto layer
  crypto: Add hash param to pkcs1pad
  sign-file: fix build with CMS support disabled
  MAINTAINERS: update tpmdd urls
  MODSIGN: linux/string.h should be #included to get memcpy()
  certs: Fix misaligned data in extra certificate list
  X.509: Handle midnight alternative notation in GeneralizedTime
  X.509: Support leap seconds
  Handle ISO 8601 leap seconds and encodings of midnight in mktime64()
  X.509: Fix leap year handling again
  PKCS#7: fix unitialized boolean 'want'
  firmware: change kernel read fail to dev_dbg()
  KEYS: Use the symbol value for list size, updated by scripts/insert-sys-cert
  KEYS: Reserve an extra certificate symbol for inserting without recompiling
  modsign: hide openssl output in silent builds
  tpm_tis: fix build warning with tpm_tis_resume
  ima: require signed IMA policy
  ima: measure and appraise the IMA policy itself
  ima: load policy using path
  ...
2016-03-17 11:33:45 -07:00
Linus Torvalds
8a284c062e Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "The timer department delivers this time:

   - Support for cross clock domain timestamps in the core code plus a
     first user.  That allows more precise timestamping for PTP and
     later for audio and other peripherals.

     The ptp/e1000e patches have been acked by the relevant maintainers
     and are carried in the timer tree to avoid merge ordering issues.

   - Support for unregistering the current clocksource watchdog.  That
     lifts a limitation for switching clocksources which has been there
     from day 1

   - The usual pile of fixes and updates to the core and the drivers.
     Nothing outstanding and exciting"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  time/timekeeping: Work around false positive GCC warning
  e1000e: Adds hardware supported cross timestamp on e1000e nic
  ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping
  x86/tsc: Always Running Timer (ART) correlated clocksource
  hrtimer: Revert CLOCK_MONOTONIC_RAW support
  time: Add history to cross timestamp interface supporting slower devices
  time: Add driver cross timestamp interface for higher precision time synchronization
  time: Remove duplicated code in ktime_get_raw_and_real()
  time: Add timekeeping snapshot code capturing system time and counter
  time: Add cycles to nanoseconds translation
  jiffies: Use CLOCKSOURCE_MASK instead of constant
  clocksource: Introduce clocksource_freq2mult()
  clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_global_timer: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_arch_timer: Implement ->set_state_oneshot_stopped()
  clocksource/drivers/arm_global_timer: Register delay timer
  clocksource/drivers/lpc32xx: Support timer-based ARM delay
  clocksource/drivers/lpc32xx: Support periodic mode
  clocksource/drivers/lpc32xx: Don't use the prescaler counter for clockevents
  clocksource/drivers/rockchip: Add err handle for rk_timer_init
  ...
2016-03-15 12:13:56 -07:00
Ingo Molnar
6436257b49 time/timekeeping: Work around false positive GCC warning
Newer GCC versions trigger the following warning:

  kernel/time/timekeeping.c: In function ‘get_device_system_crosststamp’:
  kernel/time/timekeeping.c:987:5: warning: ‘clock_was_set_seq’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    if (discontinuity) {
     ^
  kernel/time/timekeeping.c:1045:15: note: ‘clock_was_set_seq’ was declared here
    unsigned int clock_was_set_seq;
                 ^

GCC clearly is unable to recognize that the 'do_interp' boolean tracks
the initialization status of 'clock_was_set_seq'.

The GCC version used was:

  gcc version 5.3.1 20151207 (Red Hat 5.3.1-2) (GCC)

Work it around by initializing clock_was_set_seq to 0. Compilers that
are able to recognize the code flow will eliminate the unnecessary
initialization.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-08 11:09:53 +01:00
Thomas Gleixner
6936527233 Merge branch 'fortglx/4.6/time' of https://git.linaro.org/people/john.stultz/linux into timers/core
Pull the cross-timestamp infrastructure from John Stultz.

Allows precise correlation of device timestamps with system time. Primary use
cases being PTP and audio.
2016-03-04 08:12:27 +01:00
Thomas Gleixner
82e88ff1ea hrtimer: Revert CLOCK_MONOTONIC_RAW support
Revert commits:
a6e707ddbd: KVM: arm/arm64: timer: Switch to CLOCK_MONOTONIC_RAW
9006a01829: hrtimer: Catch illegal clockids
9c808765e8: hrtimer: Add support for CLOCK_MONOTONIC_RAW

Marc found out, that there are fundamental issues with that patch series
because __hrtimer_get_next_event() and hrtimer_forward() need support for
CLOCK_MONOTONIC_RAW. Nothing which is easily fixed, so revert the whole lot.

Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/56D6CEF0.8060607@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-03-03 11:11:12 +01:00
Christopher S. Hall
2c756feb18 time: Add history to cross timestamp interface supporting slower devices
Another representative use case of time sync and the correlated
clocksource (in addition to PTP noted above) is PTP synchronized
audio.

In a streaming application, as an example, samples will be sent and/or
received by multiple devices with a presentation time that is in terms
of the PTP master clock. Synchronizing the audio output on these
devices requires correlating the audio clock with the PTP master
clock. The more precise this correlation is, the better the audio
quality (i.e. out of sync audio sounds bad).

From an application standpoint, to correlate the PTP master clock with
the audio device clock, the system clock is used as a intermediate
timebase. The transforms such an application would perform are:

    System Clock <-> Audio clock
    System Clock <-> Network Device Clock [<-> PTP Master Clock]

Modern Intel platforms can perform a more accurate cross timestamp in
hardware (ART,audio device clock).  The audio driver requires
ART->system time transforms -- the same as required for the network
driver. These platforms offload audio processing (including
cross-timestamps) to a DSP which to ensure uninterrupted audio
processing, communicates and response to the host only once every
millsecond. As a result is takes up to a millisecond for the DSP to
receive a request, the request is processed by the DSP, the audio
output hardware is polled for completion, the result is copied into
shared memory, and the host is notified. All of these operation occur
on a millisecond cadence.  This transaction requires about 2 ms, but
under heavier workloads it may take up to 4 ms.

Adding a history allows these slow devices the option of providing an
ART value outside of the current interval. In this case, the callback
provided is an accessor function for the previously obtained counter
value. If get_system_device_crosststamp() receives a counter value
previous to cycle_last, it consults the history provided as an
argument in history_ref and interpolates the realtime and monotonic
raw system time using the provided counter value. If there are any
clock discontinuities, e.g. from calling settimeofday(), the monotonic
raw time is interpolated in the usual way, but the realtime clock time
is adjusted by scaling the monotonic raw adjustment.

When an accessor function is used a history argument *must* be
provided. The history is initialized using ktime_get_snapshot() and
must be called before the counter values are read.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Fixed up cycles_t/cycle_t type confusion]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-02 17:13:17 -08:00
Christopher S. Hall
8006c24595 time: Add driver cross timestamp interface for higher precision time synchronization
ACKNOWLEDGMENT: cross timestamp code was developed by Thomas Gleixner
<tglx@linutronix.de>. It has changed considerably and any mistakes are
mine.

The precision with which events on multiple networked systems can be
synchronized using, as an example, PTP (IEEE 1588, 802.1AS) is limited
by the precision of the cross timestamps between the system clock and
the device (timestamp) clock. Precision here is the degree of
simultaneity when capturing the cross timestamp.

Currently the PTP cross timestamp is captured in software using the
PTP device driver ioctl PTP_SYS_OFFSET. Reads of the device clock are
interleaved with reads of the realtime clock. At best, the precision
of this cross timestamp is on the order of several microseconds due to
software latencies. Sub-microsecond precision is required for
industrial control and some media applications. To achieve this level
of precision hardware supported cross timestamping is needed.

The function get_device_system_crosstimestamp() allows device drivers
to return a cross timestamp with system time properly scaled to
nanoseconds.  The realtime value is needed to discipline that clock
using PTP and the monotonic raw value is used for applications that
don't require a "real" time, but need an unadjusted clock time.  The
get_device_system_crosstimestamp() code calls back into the driver to
ensure that the system counter is within the current timekeeping
update interval.

Modern Intel hardware provides an Always Running Timer (ART) which is
exactly related to TSC through a known frequency ratio. The ART is
routed to devices on the system and is used to precisely and
simultaneously capture the device clock with the ART.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Reworked to remove extra structures and simplify calling]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-02 17:13:10 -08:00
Christopher S. Hall
ba26621e63 time: Remove duplicated code in ktime_get_raw_and_real()
The code in ktime_get_snapshot() is a superset of the code in
ktime_get_raw_and_real() code. Further, ktime_get_raw_and_real() is
called only by the PPS code, pps_get_ts(). Consolidate the
pps_get_ts() code into a single function calling ktime_get_snapshot()
and eliminate ktime_get_raw_and_real(). A side effect of this is that
the raw and real results of pps_get_ts() correspond to exactly the
same clock cycle. Previously these values represented separate reads
of the system clock.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-02 17:13:02 -08:00
Christopher S. Hall
9da0f49c87 time: Add timekeeping snapshot code capturing system time and counter
In the current timekeeping code there isn't any interface to
atomically capture the current relationship between the system counter
and system time. ktime_get_snapshot() returns this triple (counter,
monotonic raw, realtime) in the system_time_snapshot struct.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Moved structure definitions around to clean things up,
 fixed cycles_t/cycle_t confusion.]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-02 17:12:50 -08:00
Christopher S. Hall
6bd58f09e1 time: Add cycles to nanoseconds translation
The timekeeping code does not currently provide a way to translate
externally provided clocksource cycles to system time. The cycle count
is always provided by the result clocksource read() method internal to
the timekeeping code. The added function timekeeping_cycles_to_ns()
calculated a nanosecond value from a cycle count that can be added to
tk_read_base.base value yielding the current system time. This allows
clocksource cycle values external to the timekeeping code to provide a
cycle count that can be transformed to system time.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-03-02 17:08:54 -08:00
Frederic Weisbecker
4f49b90abb sched-clock: Migrate to use new tick dependency mask model
Instead of checking sched_clock_stable from the nohz subsystem to verify
its tick dependency, migrate it to the new mask in order to include it
to the all-in-one check.

Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:44:57 +01:00
Frederic Weisbecker
b78783000d posix-cpu-timers: Migrate to use new tick dependency mask model
Instead of providing asynchronous checks for the nohz subsystem to verify
posix cpu timers tick dependency, migrate the latter to the new mask.

In order to keep track of the running timers and expose the tick
dependency accordingly, we must probe the timers queuing and dequeuing
on threads and process lists.

Unfortunately it implies both task and signal level dependencies. We
should be able to further optimize this and merge all that on the task
level dependency, at the cost of a bit of complexity and may be overhead.

Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:44:27 +01:00
Frederic Weisbecker
76d92ac305 sched: Migrate sched to use new tick dependency mask model
Instead of providing asynchronous checks for the nohz subsystem to verify
sched tick dependency, migrate sched to the new mask.

Everytime a task is enqueued or dequeued, we evaluate the state of the
tick dependency on top of the policy of the tasks in the runqueue, by
order of priority:

SCHED_DEADLINE: Need the tick in order to periodically check for runtime
SCHED_FIFO    : Don't need the tick (no round-robin)
SCHED_RR      : Need the tick if more than 1 task of the same priority
                for round robin (simplified with checking if more than
                one SCHED_RR task no matter what priority).
SCHED_NORMAL  : Need the tick if more than 1 task for round-robin.

We could optimize that further with one flag per sched policy on the tick
dependency mask and perform only the checks relevant to the policy
concerned by an enqueue/dequeue operation.

Since the checks aren't based on the current task anymore, we could get
rid of the task switch hook but it's still needed for posix cpu
timers.

Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:43:41 +01:00
Frederic Weisbecker
555e0c1ef7 perf: Migrate perf to use new tick dependency mask model
Instead of providing asynchronous checks for the nohz subsystem to verify
perf event tick dependency, migrate perf to the new mask.

Perf needs the tick for two situations:

1) Freq events. We could set the tick dependency when those are
installed on a CPU context. But setting a global dependency on top of
the global freq events accounting is much easier. If people want that
to be optimized, we can still refine that on the per-CPU tick dependency
level. This patch dooesn't change the current behaviour anyway.

2) Throttled events: this is a per-cpu dependency.

Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:43:00 +01:00
Frederic Weisbecker
e6e6cc22e0 nohz: Use enum code for tick stop failure tracing message
It makes nohz tracing more lightweight, standard and easier to parse.

Examples:

       user_loop-2904  [007] d..1   517.701126: tick_stop: success=1 dependency=NONE
       user_loop-2904  [007] dn.1   518.021181: tick_stop: success=0 dependency=SCHED
    posix_timers-6142  [007] d..1  1739.027400: tick_stop: success=0 dependency=POSIX_TIMER
       user_loop-5463  [007] dN.1  1185.931939: tick_stop: success=0 dependency=PERF_EVENTS

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:42:15 +01:00
Frederic Weisbecker
d027d45d8a nohz: New tick dependency mask
The tick dependency is evaluated on every IRQ and context switch. This
consists is a batch of checks which determine whether it is safe to
stop the tick or not. These checks are often split in many details:
posix cpu timers, scheduler, sched clock, perf events.... each of which
are made of smaller details: posix cpu timer involves checking process
wide timers then thread wide timers. Perf involves checking freq events
then more per cpu details.

Checking these informations asynchronously every time we update the full
dynticks state bring avoidable overhead and a messy layout.

Let's introduce instead tick dependency masks: one for system wide
dependency (unstable sched clock, freq based perf events), one for CPU
wide dependency (sched, throttling perf events), and task/signal level
dependencies (posix cpu timers). The subsystems are responsible
for setting and clearing their dependency through a set of APIs that will
take care of concurrent dependency mask modifications and kick targets
to restart the relevant CPU tick whenever needed.

This new dependency engine stays beside the old one until all subsystems
having a tick dependency are converted to it.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-03-02 16:41:39 +01:00
David Howells
ede5147d51 Handle ISO 8601 leap seconds and encodings of midnight in mktime64()
Handle the following ISO 8601 features in mktime64():

 (1) Leap seconds.

     Leap seconds are indicated by the seconds parameter being the value
     60.  Handle this by treating it the same as 00 of the following
     minute.

     It has been pointed out that a minute may contain two leap seconds.
     However, pending discussion of what that looks like and how to handle
     it, I'm not going to concern myself with it.

 (2) Alternate encodings of midnight.

     Two different encodings of midnight are permitted - 00:00:00 and
     24:00:00 - the first is midnight today and the second is midnight
     tomorrow and is exactly equivalent to the first with tomorrow's date.

As it happens, we don't actually need to change mktime64() to handle either
of these - just comment them as valid parameters.

These facility will be used by the X.509 parser.  Doing it in mktime64()
makes the policy common to the whole kernel and easier to find.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
cc: John Stultz <john.stultz@linaro.org>
cc: Rudolf Polzer <rpolzer@google.com>
cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
2016-02-29 14:29:40 +00:00
Alexander Kuleshov
232d26373d jiffies: Use CLOCKSOURCE_MASK instead of constant
The CLOCKSOURCE_MASK(32) macro expands to the same value, but
makes code more readable.

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Link: http://lkml.kernel.org/r/1456542854-22104-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-02-27 08:55:31 +01:00
Masanari Iida
fc4fa6e112 treewide: Fix typo in printk
This patch fix spelling typos found in printk and Kconfig.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-02-15 11:18:22 +01:00
Frederic Weisbecker
8537bb95a6 nohz: Implement wide kick on top of irq work
It simplifies it and allows wide kick to be performed, even when IRQs
are disabled, without an asynchronous level in the middle.

This comes at a cost of some more overhead on features like perf and
posix cpu timers slow-paths, which is probably not much important
for nohz full users.

Requested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2016-02-13 15:34:28 +01:00
Linus Torvalds
dc799d0179 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
 "The timer departement delivers:

   - a regression fix for the NTP code along with a proper selftest
   - prevent a spurious timer interrupt in the NOHZ lowres code
   - a fix for user space interfaces returning the remaining time on
     architectures with CONFIG_TIME_LOW_RES=y
   - a few patches to fix COMPILE_TEST fallout"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/nohz: Set the correct expiry when switching to nohz/lowres mode
  clocksource: Fix dependencies for archs w/o HAS_IOMEM
  clocksource: Select CLKSRC_MMIO where needed
  tick/sched: Hide unused oneshot timer code
  kselftests: timers: Add adjtimex SETOFFSET validity tests
  ntp: Fix ADJ_SETOFFSET being used w/ ADJ_NANO
  itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper
  posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper
  timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper
  hrtimer: Handle remaining time proper for TIME_LOW_RES
  clockevents/tcb_clksrc: Prevent disabling an already disabled clock
2016-01-31 15:49:06 -08:00
Wanpeng Li
1ca8ec532f tick/nohz: Set the correct expiry when switching to nohz/lowres mode
commit 0ff53d0964 sets the next tick interrupt to the last jiffies update,
i.e. in the past, because the forward operation is invoked before the set
operation. There is no resulting damage (yet), but we get an extra pointless
tick interrupt.

Revert the order so we get the next tick interrupt in the future.

Fixes: commit 0ff53d0964 "tick: sched: Force tick interrupt and get rid of softirq magic"
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1453893967-3458-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-27 12:45:57 +01:00
Vitaly Kuznetsov
bbf66d897a clocksource: Allow unregistering the watchdog
Hyper-V vmbus module registers TSC page clocksource when loaded. This is
the clocksource with the highest rating and thus it becomes the watchdog
making unloading of the vmbus module impossible.
Separate clocksource_select_watchdog() from clocksource_enqueue_watchdog()
and use it on clocksource register/rating change/unregister.

After all, lobotomized monkeys may need some love too.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1453483913-25672-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-27 12:38:05 +01:00
Marc Zyngier
9006a01829 hrtimer: Catch illegal clockids
It is way too easy to take any random clockid and feed it to
the hrtimer subsystem. At best, it gets mapped to a monotonic
base, but it would be better to just catch illegal values as
early as possible.

This patch does exactly that, mapping illegal clockids to an
illegal base index, and panicing when we detect the illegal
condition.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Link: http://lkml.kernel.org/r/1452879670-16133-3-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-27 12:38:04 +01:00
Marc Zyngier
9c808765e8 hrtimer: Add support for CLOCK_MONOTONIC_RAW
The KVM/ARM timer implementation arms a hrtimer when a vcpu is
blocked (usually because it is waiting for an interrupt)
while its timer is going to kick in the future.

It is essential that this timer doesn't get adjusted, or the
guest will end up being woken-up at the wrong time (NTP running
on the host seems to confuse the hell out of some guests).

In order to allow this, let's add CLOCK_MONOTONIC_RAW support
to hrtimer (it is so far only supported for posix timers). It also
has the (limited) benefit of fixing de0421d53b ("mac80211_hwsim:
shuffle code to prepare for dynamic radios"), which already uses
this functionnality without realizing wasn't implemented (just being
lucky...).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Link: http://lkml.kernel.org/r/1452879670-16133-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-27 12:38:04 +01:00
Arnd Bergmann
7809998ab1 tick/sched: Hide unused oneshot timer code
A couple of functions in kernel/time/tick-sched.c are only
relevant for oneshot timer mode, i.e. when hires-timers or
nohz mode are enabled. If both are disabled, we get gcc warnings
about them:

kernel/time/tick-sched.c:98:16: warning: 'tick_init_jiffy_update' defined but not used [-Wunused-function]
 static ktime_t tick_init_jiffy_update(void)
                ^
kernel/time/tick-sched.c:112:13: warning: 'tick_sched_do_timer' defined but not used [-Wunused-function]
 static void tick_sched_do_timer(ktime_t now)
             ^
kernel/time/tick-sched.c:134:13: warning: 'tick_sched_handle' defined but not used [-Wunused-function]
 static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
             ^

This encloses the whole set of functions in an appropriate ifdef
to avoid the warning and to make it clearer when they are used.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1453736525-1959191-1-git-send-email-arnd@arndb.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-26 16:26:06 +01:00
John Stultz
dd4e17ab70 ntp: Fix ADJ_SETOFFSET being used w/ ADJ_NANO
Recently, in commit 37cf4dc337 I forgot to check if the timeval being passed
was actually a timespec (as is signaled with ADJ_NANO).

This resulted in that patch breaking ADJ_SETOFFSET users who set
ADJ_NANO, by rejecting valid timespecs that were compared with
valid timeval ranges.

This patch addresses this by checking for the ADJ_NANO flag and
using the timepsec check instead in that case.

Reported-by: Harald Hoyer <harald@redhat.com>
Reported-by: Kay Sievers <kay@vrfy.org>
Fixes: 37cf4dc337 "time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow"
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Link: http://lkml.kernel.org/r/1453417415-19110-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-22 12:01:42 +01:00
Rafael J. Wysocki
f11aef69b2 Merge branch 'pm-cpuidle'
* pm-cpuidle:
  cpuidle: menu: Avoid pointless checks in menu_select()
  sched / idle: Drop default_idle_call() fallback from call_cpuidle()
  cpuidle: Don't enable all governors by default
  cpuidle: Default to ladder governor on ticking systems
  time: nohz: Expose tick_nohz_enabled
  cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0
2016-01-21 00:43:21 +01:00
Thomas Gleixner
51cbb5242a itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper
As Helge reported for timerfd we have the same issue in itimers. We return
remaining time larger than the programmed relative time to user space in case
of CONFIG_TIME_LOW_RES=y. Use the proper function to adjust the extra time
added in hrtimer_start_range_ns().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Helge Deller <deller@gmx.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20160114164159.528222587@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-17 11:13:55 +01:00
Thomas Gleixner
572c391726 posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper
As Helge reported for timerfd we have the same issue in posix timers. We
return remaining time larger than the programmed relative time to user space
in case of CONFIG_TIME_LOW_RES=y. Use the proper function to adjust the extra
time added in hrtimer_start_range_ns().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Helge Deller <deller@gmx.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20160114164159.450510905@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-17 11:13:55 +01:00
Thomas Gleixner
203cbf77de hrtimer: Handle remaining time proper for TIME_LOW_RES
If CONFIG_TIME_LOW_RES is enabled we add a jiffie to the relative timeout to
prevent short sleeps, but we do not account for that in interfaces which
retrieve the remaining time.

Helge observed that timerfd can return a remaining time larger than the
relative timeout. That's not expected and breaks userland test programs.

Store the information that the timer was armed relative and provide functions
to adjust the remaining time. To avoid bloating the hrtimer struct make state
a u8, which as a bonus results in better code on x86 at least.

Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20160114164159.273328486@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-17 11:13:55 +01:00
Jean Delvare
46373a15f6 time: nohz: Expose tick_nohz_enabled
The cpuidle subsystem needs it.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-01-15 22:34:39 +01:00
Thomas Gleixner
1f16f116b0 Merge branches 'clockevents/4.4-fixes' and 'clockevents/4.5-fixes' of http://git.linaro.org/people/daniel.lezcano/linux into timers/urgent
Pull in fixes from Daniel Lezcano:

 - Fix the vt8500 timer leading to a system lock up when dealing with too
   small delta (Roman Volkov)

 - Select the CLKSRC_MMIO when the fsl_ftm_timer is enabled with COMPILE_TEST
   (Daniel Lezcano)

 - Prevent to compile timers using the 'iomem' API when the architecture has
   not HAS_IOMEM set (Richard Weinberger)
2016-01-12 11:01:12 +01:00
Linus Torvalds
0f8c790103 Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue update from Tejun Heo:
 "Workqueue changes for v4.5.  One cleanup patch and three to improve
  the debuggability.

  Workqueue now has a stall detector which dumps workqueue state if any
  worker pool hasn't made forward progress over a certain amount of time
  (30s by default) and also triggers a warning if a workqueue which can
  be used in memory reclaim path tries to wait on something which can't
  be.

  These should make workqueue hangs a lot easier to debug."

* 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: simplify the apply_workqueue_attrs_locked()
  workqueue: implement lockup detector
  watchdog: introduce touch_softlockup_watchdog_sched()
  workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue
2016-01-11 18:53:13 -08:00
Linus Torvalds
b4cee21ee0 Merge branches 'timers-core-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates - and a leftover fix - from Thomas Gleixner:
 "A rather large (commit wise) update from the timer side:

   - A bulk update to make compile tests work in the clocksource drivers

   - An overhaul of the h8300 timers

   - Some more Y2038 work

   - A few overflow prevention checks in the timekeeping/ntp code

   - The usual pile of fixes and improvements to the various
     clocksource/clockevent drivers and core code"

Also:
 "A single fix for the posix-clock poll code which did not make it into
  4.4"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (84 commits)
  clocksource/drivers/acpi_pm: Convert to pr_* macros
  clocksource: Make clocksource validation work for all clocksources
  timekeeping: Cap adjustments so they don't exceed the maxadj value
  ntp: Fix second_overflow's input parameter type to be 64bits
  ntp: Change time_reftime to time64_t and utilize 64bit __ktime_get_real_seconds
  timekeeping: Provide internal function __ktime_get_real_seconds
  clocksource/drivers/h8300: Use ioread / iowrite
  clocksource/drivers/h8300: Initializer cleanup.
  clocksource/drivers/h8300: Simplify delta handling
  clocksource/drivers/h8300: Fix timer not overflow case
  clocksource/drivers/h8300: Change to overflow interrupt
  clocksource/drivers/lpc32: Correct pr_err() output format
  clocksource/drivers/arm_global_timer: Fix suspend resume
  clocksource/drivers/pistachio: Fix wrong calculated clocksource read value
  clockevents/drivers/arm_global_timer: Use writel_relaxed in gt_compare_set
  clocksource/drivers/dw_apb_timer: Inline apbt_readl and apbt_writel
  clocksource/drivers/dw_apb_timer: Use {readl|writel}_relaxed in critical path
  clocksource/drivers/dw_apb_timer: Fix apbt_readl return types
  clocksource/drivers/tango-xtal: Replace code by clocksource_mmio_init
  clocksource/drivers/h8300: Increase the compilation test coverage
  ...

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-clock: Fix return code on the poll method's error path
2016-01-11 18:06:43 -08:00
Richard Cochran
1b9f23727a posix-clock: Fix return code on the poll method's error path
The posix_clock_poll function is supposed to return a bit mask of
POLLxxx values.  However, in case the hardware has disappeared (due to
hot plugging for example) this code returns -ENODEV in a futile
attempt to throw an error at the file descriptor level.  The kernel's
file_operations interface does not accept such error codes from the
poll method.  Instead, this function aught to return POLLERR.

The value -ENODEV does, in fact, contain the POLLERR bit (and almost
all the other POLLxxx bits as well), but only by chance.  This patch
fixes code to return a proper bit mask.

Credit goes to Markus Elfring for pointing out the suspicious
signed/unsigned mismatch.

Reported-by: Markus Elfring <elfring@users.sourceforge.net>
igned-off-by: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-12-29 11:33:06 +01:00
Yang Yingliang
1f45f1f33c clocksource: Make clocksource validation work for all clocksources
The clocksource validation which makes sure that the newly read value
is not smaller than the last value only works if the clocksource mask
is 64bit, i.e. the counter is 64bit wide. But we want to use that
mechanism also for clocksources which are less than 64bit wide.

So instead of checking whether bit 63 is set, we check whether the
most significant bit of the clocksource mask is set in the delta
result. If it is set, we return 0.

[ tglx: Simplified the implementation, added a comment and massaged
  	the commit message ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Link: http://lkml.kernel.org/r/56349607.6070708@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-12-19 15:59:57 +01:00
Thomas Gleixner
e2666d6906 Merge branch 'fortglx/4.5/time' of https://git.linaro.org/people/john.stultz/linux into timers/core
Get the core time(keeping) updates from John Stultz

    - NTP robustness tweaks
    - Another signed overflow nailed down
    - More y2038 changes
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    - Selftest fixes
2015-12-19 12:03:17 +01:00
John Stultz
ec02b076ce timekeeping: Cap adjustments so they don't exceed the maxadj value
Thus its been occasionally noted that users have seen
confusing warnings like:

    Adjusting tsc more than 11% (5941981 vs 7759439)

We try to limit the maximum total adjustment to 11% (10% tick
adjustment + 0.5% frequency adjustment). But this is done by
bounding the requested adjustment values, and the internal
steering that is done by tracking the error from what was
requested and what was applied, does not have any such limits.

This is usually not problematic, but in some cases has a risk
that an adjustment could cause the clocksource mult value to
overflow, so its an indication things are outside of what is
expected.

It ends up most of the reports of this 11% warning are on systems
using chrony, which utilizes the adjtimex() ADJ_TICK interface
(which allows a +-10% adjustment). The original rational for
ADJ_TICK unclear to me but my assumption it was originally added
to allow broken systems to get a big constant correction at boot
(see adjtimex userspace package for an example) which would allow
the system to work w/ ntpd's 0.5% adjustment limit.

Chrony uses ADJ_TICK to make very aggressive short term corrections
(usually right at startup). Which push us close enough to the max
bound that a few late ticks can cause the internal steering to push
past the max adjust value (tripping the warning).

Thus this patch adds some extra logic to enforce the max adjustment
cap in the internal steering.

Note: This has the potential to slow corrections when the ADJ_TICK
value is furthest away from the default value. So it would be good to
get some testing from folks using chrony, to make sure we don't
cause any troubles there.

Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Tested-by: Miroslav Lichvar <mlichvar@redhat.com>
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-16 16:50:57 -08:00
DengChao
c796348774 ntp: Fix second_overflow's input parameter type to be 64bits
The function "second_overflow" uses "unsign long"
as its input parameter type which will overflow after
year 2106 on 32bit systems.

Thus this patch replaces it with time64_t type.

While the 64-bit division is expensive, "next_ntp_leap_sec"
has been calculated already, so we can just re-use it in the
TIME_INS/DEL cases, allowing one expensive division per
leapsecond instead of re-doing the divsion once a second after
the leap flag has been set.

Signed-off-by: DengChao <chao.deng@linaro.org>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-16 16:50:56 -08:00
DengChao
0af864651b ntp: Change time_reftime to time64_t and utilize 64bit __ktime_get_real_seconds
The type of static variant "time_reftime" and the call of
get_seconds in ntp are both not y2038 safe.

So change the type of time_reftime to time64_t and replace
get_seconds with __ktime_get_real_seconds.

The local variant "secs" in ntp_update_offset represents
seconds between now and last ntp adjustment, it seems impossible
that this time will last more than 68 years, so keep its type as
"long".

Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: DengChao <chao.deng@linaro.org>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-16 16:50:55 -08:00
DengChao
dee3665416 timekeeping: Provide internal function __ktime_get_real_seconds
In order to fix Y2038 issues in the ntp code we will need replace
get_seconds() with ktime_get_real_seconds() but as the ntp code uses
the timekeeping lock which is also used by ktime_get_real_seconds(),
we need a version without locking.
Add a new function __ktime_get_real_seconds() in timekeeping to
do this.

Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: DengChao <chao.deng@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-16 16:50:55 -08:00
John Stultz
37cf4dc337 time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow
For adjtimex()'s ADJ_SETOFFSET, make sure the tv_usec value is
sane. We might multiply them later which can cause an overflow
and undefined behavior.

This patch introduces new helper functions to simplify the
checking code and adds comments to clarify

Orginally this patch was by Sasha Levin, but I've basically
rewritten it, so he should get credit for finding the issue
and I should get the blame for any mistakes made since.

Also, credit to Richard Cochran for the phrasing used in the
comment for what is considered valid here.

Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-10 22:41:06 -08:00
Sasha Levin
52d189f1b3 ntp: Verify offset doesn't overflow in ntp_update_offset
We need to make sure that the offset is valid before manipulating it,
otherwise it might overflow on the multiplication.

Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: Reworked one of the checks so it makes more sense]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-10 22:41:05 -08:00
Tejun Heo
03e0d4610b watchdog: introduce touch_softlockup_watchdog_sched()
touch_softlockup_watchdog() is used to tell watchdog that scheduler
stall is expected.  One group of usage is from paths where the task
may not be able to yield for a long time such as performing slow PIO
to finicky device and coming out of suspend.  The other is to account
for scheduler and timer going idle.

For scheduler softlockup detection, there's no reason to distinguish
the two cases; however, workqueue lockup detector is planned and it
can use the same signals from the former group while the latter would
spuriously prevent detection.  This patch introduces a new function
touch_softlockup_watchdog_sched() and convert the latter group to call
it instead.  For now, it just calls touch_softlockup_watchdog() and
there's no functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
2015-12-08 11:29:42 -05:00
Seiichi Ikarashi
390dd67c47 clocksource: Add CPU info to clocksource watchdog reporting
The clocksource watchdog reporting was improved by 0b046b217a.
I want to add the info of CPU where the watchdog detects a
deviation because it is necessary to identify the trouble spot
if the clocksource is TSC.

Signed-off-by: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-07 12:15:28 -08:00