The non-scalar ktime_t implementation is basically a timespec
which has to be changed to support dates past 2038 on 32bit
systems.

This patch removes the non-scalar ktime_t implementation, forcing
the scalar s64 nanosecond version on all architectures.

This may have additional performance overhead on some 32bit
systems when converting between ktime_t and timespec structures,
however the majority of 32bit systems (arm and i386) were already
using scalar ktime_t, so no performance regressions will be seen
on those platforms.

On affected platforms, I'm open to finding optimizations, including
avoiding converting to timespecs where possible.

[ tglx: We can now cleanup the ktime_t.tv64 mess, but thats a
  different issue and we can throw a coccinelle script at it ]
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Rather then having two similar but totally different implementations
that provide timekeeping state to the hrtimer code, try to unify the
two implementations to be more simliar.

Thus this clarifies ktime_get_update_offsets to
ktime_get_update_offsets_now and changes get_xtime...  to
ktime_get_update_offsets_tick.
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Kay Sievers noted that the ALWAYS_USE_PERSISTENT_CLOCK config,
which enables some minor compile time optimization to avoid
uncessary code in mostly the suspend/resume path could cause
problems for userland.

In particular, the dependency for RTC_HCTOSYS on
!ALWAYS_USE_PERSISTENT_CLOCK, which avoids setting the time
twice and simplifies suspend/resume, has the side effect
of causing the /sys/class/rtc/rtcN/hctosys flag to always be
zero, and this flag is commonly used by udev to setup the
/dev/rtc symlink to /dev/rtcN, which can cause pain for
older applications.

While the udev rules could use some work to be less fragile,
breaking userland should strongly be avoided. Additionally
the compile time optimizations are fairly minor, and the code
being optimized is likely to be reworked in the future, so
lets revert this change.
Reported-by: NKay Sievers <kay@vrfy.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Cc: stable <stable@vger.kernel.org> #3.9
Cc: Feng Tang <feng.tang@intel.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Link: http://lkml.kernel.org/r/1366828376-18124-1-git-send-email-john.stultz@linaro.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This add a CLOCK_TAI clockid and the needed accessors.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Currently NTP manages the TAI offset. Since there's plans for a
CLOCK_TAI clockid, push the TAI management into the timekeeping
core.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

At init time, if the system time is "warped" forward in warp_clock()
it will differ from the hardware clock by sys_tz.tz_minuteswest.  This time
difference is not taken into account when ntp updates the hardware clock,
and this causes the system time to jump forward by this offset every reboot.

The kernel must take this offset into account when writing the system time
to the hardware clock in the ntp code.  This patch adds
persistent_clock_is_local which indicates that an offset has been applied
in warp_clock() and accounts for the "warp" before writing the hardware
clock.

x86 does not have this problem as rtc writes are software limited to a
+/-15 minute window relative to the current rtc time.  Other arches, such
as powerpc, however do a full synchronization of the system time to the
rtc and will see this problem.

[v2]: generated against tip/timers/core
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Jason pointed out the HAS_PERSISTENT_CLOCK name isn't
quite accurate for the config, as some systems may have
the persistent_clock in some cases, but not always.

So change the config name to the more clear
ALWAYS_USE_PERSISTENT_CLOCK.
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Make the persistent clock check a kernel config option, so that some
platform can explicitely select it, also make CONFIG_RTC_HCTOSYS and
RTC_SYSTOHC depend on its non-existence, which could prevent the
persistent clock and RTC code from doing similar thing twice during
system's init/suspend/resume phases.

If the CONFIG_HAS_PERSISTENT_CLOCK=n, then no change happens for kernel
which still does the persistent clock check in timekeeping_init().

Cc: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NFeng Tang <feng.tang@intel.com>
[jstultz: Added dependency for RTC_SYSTOHC as well]
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

In current kernel, there are several places which need to check
whether there is a persistent clock for the platform. Current check
is done by calling the read_persistent_clock() and validating its
return value.

So one optimization is to do the check only once in timekeeping_init(),
and use a flag persistent_clock_exist to record it.

v2: Add a has_persistent_clock() helper function, as suggested by John.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NFeng Tang <feng.tang@intel.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

The pstore RAM backend can get called during resume, and must be defensive
against a suspended time source. Expose getnstimeofday logic that returns
an error instead of a WARN. This can be detected and the timestamp can
be zeroed out.
Reported-by: NDoug Anderson <dianders@chromium.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Currently, whenever CONFIG_ARCH_USES_GETTIMEOFFSET is enabled, each
arch core provides a single implementation of arch_gettimeoffset(). In
many cases, different sub-architectures, different machines, or
different timer providers exist, and so the arch ends up implementing
arch_gettimeoffset() as a call-through-pointer anyway. Examples are
ARM, Cris, M68K, and it's arguable that the remaining architectures,
M32R and Blackfin, should be doing this anyway.

Modify arch_gettimeoffset so that it itself is a function pointer, which
the arch initializes. This will allow later changes to move the
initialization of this function into individual machine support or timer
drivers. This is particularly useful for code in drivers/clocksource
which should rely on an arch-independant mechanism to register their
implementation of arch_gettimeoffset().

This patch also converts the Cris architecture to set arch_gettimeoffset
directly to the final implementation in time_init(), because Cris already
had separate time_init() functions per sub-architecture. M68K and ARM
are converted to set arch_gettimeoffset to the final implementation in
later patches, because they already have function pointers in place for
this purpose.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Signed-off-by: NStephen Warren <swarren@nvidia.com>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

Andreas Bombe reported that the added ktime_t overflow checking added to
timespec_valid in commit 4e8b1452 ("time: Improve sanity checking of
timekeeping inputs") was causing problems with X.org because it caused
timeouts larger then KTIME_T to be invalid.

Previously, these large timeouts would be clamped to KTIME_MAX and would
never expire, which is valid.

This patch splits the ktime_t overflow checking into a new
timespec_valid_strict function, and converts the timekeeping codes
internal checking to use this more strict function.
Reported-and-tested-by: NAndreas Bombe <aeb@debian.org>
Cc: Zhouping Liu <zliu@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Unexpected behavior could occur if the time is set to a value large
enough to overflow a 64bit ktime_t (which is something larger then the
year 2262).

Also unexpected behavior could occur if large negative offsets are
injected via adjtimex.

So this patch improves the sanity check timekeeping inputs by
improving the timespec_valid() check, and then makes better use of
timespec_valid() to make sure we don't set the time to an invalid
negative value or one that overflows ktime_t.

Note: This does not protect from setting the time close to overflowing
ktime_t and then letting natural accumulation cause the overflow.
Reported-by: NCAI Qian <caiqian@redhat.com>
Reported-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Zhouping Liu <zliu@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1344454580-17031-1-git-send-email-john.stultz@linaro.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Recently, glibc made a change to suppress sign-conversion warnings in
FD_SET (glibc commit ceb9e56b3d1).  This uncovered an issue with the
kernel's definition of __NFDBITS if applications #include
<linux/types.h> after including <sys/select.h>.  A build failure would
be seen when passing the -Werror=sign-compare and -D_FORTIFY_SOURCE=2
flags to gcc.

It was suggested that the kernel should either match the glibc
definition of __NFDBITS or remove that entirely.  The current in-kernel
uses of __NFDBITS can be replaced with BITS_PER_LONG, and there are no
uses of the related __FDELT and __FDMASK defines.  Given that, we'll
continue the cleanup that was started with commit 8b3d1cda
("posix_types: Remove fd_set macros") and drop the remaining unused
macros.

Additionally, linux/time.h has similar macros defined that expand to
nothing so we'll remove those at the same time.
Reported-by: NJeff Law <law@redhat.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
CC: <stable@vger.kernel.org>
Signed-off-by: NJosh Boyer <jwboyer@redhat.com>
[ .. and fix up whitespace as per akpm ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The function, timekeeping_leap_insert, was removed in commit
6b43ae8aSigned-off-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit 9863c90f (x86, vmware: Remove
deprecated VMI kernel support) removed the only place which set
no_sync_cmos_clock. Since that commit, this variable is never set.
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Delete the __FD_*() functions for operating on fd_set structs from
linux/time.h as they're no longer used within the kernel with the preceding
patch and are not exported to userspace.

Whilst linux/time.h *does* export the FD_*() equivalents as wrappers around
__FD_*(), userspace provides its own definition of __FD_*().

Note that the definition of FD_ZERO() in linux/time.h may not be used with the
fd_sets associated with struct fdtable as the fd_set may have been allocated in
a truncated fashion.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216175006.23314.18984.stgit@warthog.procyon.org.ukSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>

<asm/posix_types.h> includes a set of macros that operate on file
descriptors.  Way long ago those were exported to user space, but
nowadays they are #ifdef __KERNEL__.

However, they are nothing but standard (nonatomic) bit operations, and
we already have optimized versions of bit operations in the kernel.
We can't include <linux/bitops.h> in <asm/posix_types.h> but we can
move the definitions to <linux/time.h> and define them there in terms
of standard kernel bitops.

[ v2: folds the following fixes in:

  a) Stray space in __FD_SET(), reported by Andrew Morton
  b) #include <linux/string.h> needed for memset(), reported by Tony Luck ]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1328677745-20121-22-git-send-email-hpa@zytor.com
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>

Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the
timer interrupt. Yes, I did not think about it, because the solution
was so elegant. I didn't like the extra list in timerfd when it was
proposed some time ago, but with a rcu based list the list walk it's
less horrible than the original global lock, which was held over the
list iteration.
Requested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NPeter Zijlstra <peterz@infradead.org>

Some applications must be aware of clock realtime being set
backward. A simple example is a clock applet which arms a timer for
the next minute display. If clock realtime is set backward then the
applet displays a stale time for the amount of time which the clock
was set backwards. Due to that applications poll the time because we
don't have an interface.

Extend the timerfd interface by adding a flag which puts the timer
onto a different internal realtime clock. All timers on this clock are
expired whenever the clock was set.

The timerfd core records the monotonic offset when the timer is
created. When the timer is armed, then the current offset is compared
to the previous recorded offset. When it has changed, then
timerfd_settime returns -ECANCELED. When a timer is read the offset is
compared and if it changed -ECANCELED returned to user space. Periodic
timers are not rearmed in the cancelation case.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Chris Friesen <chris.friesen@genband.com>
Tested-by: NKay Sievers <kay.sievers@vrfy.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Reviewed-by: NAlexander Shishkin <virtuoso@slind.org>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3ESigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch exposes alarm-timers to userland via the posix clock
and timers interface, using two new clockids: CLOCK_REALTIME_ALARM
and CLOCK_BOOTTIME_ALARM. Both clockids behave identically to
CLOCK_REALTIME and CLOCK_BOOTTIME, respectively, but timers
set against the _ALARM suffixed clockids will wake the system if
it is suspended.

Some background can be found here:
	https://lwn.net/Articles/429925/

The concept for Alarm-timers was inspired by the Android Alarm
driver (by Arve Hjønnevåg) found in the Android kernel tree.

See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36

While the in-kernel interface is pretty similar between
alarm-timers and Android alarm driver, the user-space interface
for the Android alarm driver is via ioctls to a new char device.
As mentioned above, I've instead chosen to export this functionality
via the posix interface, as it seemed a little simpler and avoids
creating duplicate interfaces to things like CLOCK_REALTIME and
CLOCK_MONOTONIC under alternate names (ie:ANDROID_ALARM_RTC and
ANDROID_ALARM_SYSTEMTIME).

The semantics of the Android alarm driver are different from what
this posix interface provides. For instance, threads other then
the thread waiting on the Android alarm driver are able to modify
the alarm being waited on. Also this interface does not allow
the same wakelock semantics that the Android driver provides
(ie: kernel takes a wakelock on RTC alarm-interupt, and holds it
through process wakeup, and while the process runs, until the
process either closes the char device or calls back in to wait
on a new alarm).

One potential way to implement similar semantics may be via
the timerfd infrastructure, but this needs more research.

There may also need to be some sort of sysfs system level policy
hooks that allow alarm timers to be disabled to keep them
from firing at inappropriate times (ie: laptop in a well insulated
bag, mid-flight).

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Some platforms cannot implement read_persistent_clock, as
their RTC devices are only accessible when interrupts are enabled.
This keeps them from being used by the timekeeping code on resume
to measure the time in suspend.

The RTC layer tries to work around this, by calling do_settimeofday
on resume after irqs are reenabled to set the time properly. However,
this only corrects CLOCK_REALTIME, and does not properly adjust
the sleep time value. This causes btime in /proc/stat to be incorrect
as well as making the new CLOCK_BOTTTIME inaccurate.

This patch resolves the issue by introducing a new timekeeping hook
to allow the RTC layer to inject the sleep time on resume.

The code also checks to make sure that read_persistent_clock is
nonfunctional before setting the sleep time, so that should the RTC's
HCTOSYS option be configured in on a system that does support
read_persistent_clock we will not increase the total_sleep_time twice.

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

CLOCK_MONOTONIC stops while the system is in suspend. This is because
to applications system suspend is invisible. However, there is a
growing set of applications that are wanting to be suspend-aware,
but do not want to deal with the complications of CLOCK_REALTIME
(which might jump around if settimeofday is called).

For these applications, I propose a new clockid: CLOCK_BOOTTIME.
CLOCK_BOOTTIME is idential to CLOCK_MONOTONIC, except it also
includes any time spent in suspend.

This patch add hrtimer base for CLOCK_BOOTTIME, using
get_monotonic_boottime/ktime_get_boottime, to allow
in kernel users to set timers against.

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Extend get_xtime_and_monotonic_offset to
get_xtime_and_monotonic_and_sleep_offset().

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

This adds new functions that return the monotonic time since boot
(in other words, CLOCK_MONOTONIC + suspend time).

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

This adds a kernel-internal timekeeping interface to add or subtract
a fixed amount from CLOCK_REALTIME. This makes it so kernel users or
interfaces trying to do so do not have to read the time, then add an
offset and then call settimeofday(), which adds some extra error in
comparision to just simply adding the offset in the kernel timekeeping
core.
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
LKML-Reference: <20110201134419.584311693@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Both settimeofday() and clock_settime() promise with a 'const'
attribute not to alter the arguments passed in. This patch adds the
missing 'const' attribute into the various kernel functions
implementing these calls.
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134417.545698637@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

All callers of do_timer() are converted to xtime_update(). The only
users of xtime_lock are in kernel/time/. Make both local to
kernel/time/ and remove them from the global header files.

[ tglx: Reuse tick-internal.h instead of creating another local header
  	file. Massaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

No users left. Remove it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The hrtimer code accesses timekeeping variables under
xtime_lock. Provide a sensible accessor function and use it.

[ tglx: Removed the conditionals, unused variable, fixed codingstyle
  	and massaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145905.23248.30458.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

do_timer() is primary timekeeping related. calc_global_load() is
called from do_timer() as well, but that's more for historical
reasons.

[ tglx: Fixed up the calc_global_load() reject andmassaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145855.23248.56933.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

MONOTONIC_RAW clock timestamps are ideally suited for frequency
calculation and also fit well into the original NTP hardpps design.  Now
phase and frequency can be adjusted separately: the former based on
REALTIME clock and the latter based on MONOTONIC_RAW clock.

A new function getnstime_raw_and_real is added to timekeeping subsystem to
capture both timestamps at the same time and atomically.
Signed-off-by: NAlexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Mark arguments to certain system calls as being const where they should be but
aren't.  The list includes:

 (*) The filename arguments of various stat syscalls, execve(), various utimes
     syscalls and some mount syscalls.

 (*) The filename arguments of some syscall helpers relating to the above.

 (*) The buffer argument of various write syscalls.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current computation, introduced with f12a15be, of FSEC_PER_SEC using
the multiplication of (FSEC_PER_NSEC * NSEC_PER_SEC) is performed only
with 32bit integers on small machines, resulting in an overflow and a
*very* short intervals being programmed.  An interrupt storm follows.

Note that we also have to specify FSEC_PER_SEC as being long long to
overcome the same limitations.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes xtime and wall_to_monotonic static, as planned in
Documentation/feature-removal-schedule.txt. This will allow for
further cleanups to the timekeeping core.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-10-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Provides an accessor function to replace hrtimer.c's
direct access of wall_to_monotonic.

This will allow wall_to_monotonic to be made static as
planned in Documentation/feature-removal-schedule.txt
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-9-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

After accidentally misusing timespec_add_safe, I wanted to make sure
we don't accidently trip over that issue again, so I created a simple
timespec_add() function which we can use to replace the instances
of timespec_add_safe() that don't want the overflow detection.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

With the earlier logarithmic time accumulation patch, xtime will now
always be within one "tick" of the current time, instead of possibly
half a second off.

This removes the need for the xtime_cache value, which always stored the
time at the last interrupt, so this patch cleans that up removing the
xtime_cache related code.

This patch also addresses an issue with an earlier version of this change,
where xtime_cache was normalizing xtime, which could in some cases be
not valid (ie: tv_nsec == NSEC_PER_SEC). This is fixed by handling
the edge case in update_wall_time().
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Petr Titěra <P.Titera@century.cz>
LKML-Reference: <1270589451-30773-1-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The dynamic tick allows the kernel to sleep for periods longer than a
single tick, but it does not limit the sleep time currently. In the
worst case the kernel could sleep longer than the wrap around time of
the time keeping clock source which would result in losing track of
time.

Prevent this by limiting it to the safe maximum sleep time of the
current time keeping clock source. The value is calculated when the
clock source is registered.

[ tglx: simplified the code a bit and massaged the commit msg ]
Signed-off-by: NJon Hunter <jon-hunter@ti.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <1250617512-23567-2-git-send-email-jon-hunter@ti.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>