linux-toradex.git/include/linux/ktime.h, branch v4.4.106 Linux kernel for Apalis and Colibri modules ktime: Fix ktime_divns to do signed division 2015-05-13T08:19:35+00:00 John Stultz john.stultz@linaro.org 2015-05-08T20:47:23+00:00 f7bcb70ebae0dcdb5a2d859b09e4465784d99029 It was noted that the 32bit implementation of ktime_divns() was doing unsigned division and didn't properly handle negative values. And when a ktime helper was changed to utilize ktime_divns, it caused a regression on some IR blasters. See the following bugzilla for details: https://bugzilla.redhat.com/show_bug.cgi?id=1200353 This patch fixes the problem in ktime_divns by checking and preserving the sign bit, and then reapplying it if appropriate after the division, it also changes the return type to a s64 to make it more obvious this is expected. Nicolas also pointed out that negative dividers would cause infinite loops on 32bit systems, negative dividers is unlikely for users of this function, but out of caution this patch adds checks for negative dividers for both 32-bit (BUG_ON) and 64-bit(WARN_ON) versions to make sure no such use cases creep in. [ tglx: Hand an u64 to do_div() to avoid the compiler warning ] Fixes: 166afb64511e 'ktime: Sanitize ktime_to_us/ms conversion' Reported-and-tested-by: Trevor Cordes <trevor@tecnopolis.ca> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Boyer <jwboyer@redhat.com> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1431118043-23452-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
It was noted that the 32bit implementation of ktime_divns()
was doing unsigned division and didn't properly handle
negative values.

And when a ktime helper was changed to utilize
ktime_divns, it caused a regression on some IR blasters.
See the following bugzilla for details:
  https://bugzilla.redhat.com/show_bug.cgi?id=1200353

This patch fixes the problem in ktime_divns by checking
and preserving the sign bit, and then reapplying it if
appropriate after the division, it also changes the return
type to a s64 to make it more obvious this is expected.

Nicolas also pointed out that negative dividers would
cause infinite loops on 32bit systems, negative dividers
is unlikely for users of this function, but out of caution
this patch adds checks for negative dividers for both
32-bit (BUG_ON) and 64-bit(WARN_ON) versions to make sure
no such use cases creep in.

[ tglx: Hand an u64 to do_div() to avoid the compiler warning ]

Fixes: 166afb64511e 'ktime: Sanitize ktime_to_us/ms conversion'
Reported-and-tested-by: Trevor Cordes <trevor@tecnopolis.ca>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1431118043-23452-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Merge tag 'fortglx-3.20-time' of https://git.linaro.org/people/john.stultz/linux into timers/core 2015-01-24T09:11:12+00:00 Thomas Gleixner tglx@linutronix.de 2015-01-24T09:11:12+00:00 fe31fca35d6af9176eec0024fac2ceeaacbc8639 Pull time updates from John Stultz for 3.20: * ktime division optimization * Expose a few more y2038-safe timekeeping interfaces * RTC core changes to address y2038 
Pull time updates from John Stultz for 3.20:

 * ktime division optimization
 * Expose a few more y2038-safe timekeeping interfaces
 * RTC core changes to address y2038
ktime: Optimize ktime_divns for constant divisors 2015-01-24T01:21:31+00:00 Nicolas Pitre nicolas.pitre@linaro.org 2014-12-03T19:43:06+00:00 8b618628b2bf83512fc8df5e8672619d65adfdfb At least on ARM, do_div() is optimized to turn constant divisors into an inline multiplication by the reciprocal value at compile time. However this optimization is missed entirely whenever ktime_divns() is used and the slow out-of-line division code is used all the time. Let ktime_divns() use do_div() inline whenever the divisor is constant and small enough. This will make things like ktime_to_us() and ktime_to_ms() much faster. Cc: Arnd Bergmann <arnd.bergmann@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Nicolas Pitre <nico@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> 
At least on ARM, do_div() is optimized to turn constant divisors into
an inline multiplication by the reciprocal value at compile time.
However this optimization is missed entirely whenever ktime_divns() is
used and the slow out-of-line division code is used all the time.

Let ktime_divns() use do_div() inline whenever the divisor is constant
and small enough.  This will make things like ktime_to_us() and
ktime_to_ms() much faster.

Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nicolas Pitre <nico@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime.h: Introduce ktime_ms_delta 2015-01-23T10:47:15+00:00 Chunyan Zhang zhang.chunyan@linaro.org 2014-12-17T05:11:35+00:00 41fbf3b39d5eca01527338b4d0ee15ee1ae1023c This patch adds a reusable time difference function which returns the difference in millisecond, as often used in some driver code, e.g. mtd/test, media/rc, etc. Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> Acked-by: Arnd Bergmann <arnd@linaro.org> Cc: zhang.lyra@gmail.com Cc: davem@davemloft.net Cc: john.stultz@linaro.org Cc: dborkman@redhat.com Link: http://lkml.kernel.org/r/1418793095-18780-1-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
This patch adds a reusable time difference function which returns the
difference in millisecond, as often used in some driver code, e.g.
mtd/test, media/rc, etc.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Acked-by: Arnd Bergmann <arnd@linaro.org>
Cc: zhang.lyra@gmail.com
Cc: davem@davemloft.net
Cc: john.stultz@linaro.org
Cc: dborkman@redhat.com
Link: http://lkml.kernel.org/r/1418793095-18780-1-git-send-email-zhang.chunyan@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
time: Consolidate the time accessor prototypes 2014-07-23T17:17:54+00:00 Thomas Gleixner tglx@linutronix.de 2014-07-16T21:04:02+00:00 8b094cd03b4a3793220d8d8d86a173bfea8c285b Right now we have time related prototypes in 3 different header files. Move it to a single timekeeping header file and move the core internal stuff into a core private header. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> 
Right now we have time related prototypes in 3 different header
files. Move it to a single timekeeping header file and move the core
internal stuff into a core private header.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
time: More core infrastructure for timespec64 2014-07-23T17:17:53+00:00 John Stultz john.stultz@linaro.org 2014-07-16T21:03:59+00:00 49cd6f869984692547c57621bf42697aaa7f5622 Helper and conversion functions for timespec64. Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> 
Helper and conversion functions for timespec64.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime: Change ktime_set() to take 64bit seconds value 2014-07-23T17:16:50+00:00 John Stultz john.stultz@linaro.org 2014-07-16T21:03:56+00:00 b17b20d70dcbe48dd1aa6aba073a60ddfce5d7db In order to support dates past 2038 on 32bit systems, ktime_set() needs to handle 64bit second values. [ tglx: Removed the BITS_PER_LONG check ] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> 
In order to support dates past 2038 on 32bit systems, ktime_set()
needs to handle 64bit second values.

[ tglx: Removed the BITS_PER_LONG check ]

Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime: Sanitize ktime_to_us/ms conversion 2014-07-23T17:16:50+00:00 Thomas Gleixner tglx@linutronix.de 2014-07-16T21:03:55+00:00 166afb64511eef08e13331b970c44fe91cea45ef With the plain nanoseconds based ktime_t we can simply use ktime_divns() instead of going through loops and hoops of timespec/timeval conversion. Reported-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> 
With the plain nanoseconds based ktime_t we can simply use
ktime_divns() instead of going through loops and hoops of
timespec/timeval conversion.

Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime: Kill non-scalar ktime_t implementation for 2038 2014-07-23T17:16:50+00:00 John Stultz john.stultz@linaro.org 2014-07-16T21:03:53+00:00 24e4a8c3e8868874835b0f1ad6dd417341e99822 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: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> 
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: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime: add ktime_after and ktime_before helper 2014-06-11T19:23:17+00:00 Daniel Borkmann dborkman@redhat.com 2014-06-11T16:19:28+00:00 67cb9366ff5f99868100198efba5ca88aaa6ad25 Add two minimal helper functions analogous to time_before() and time_after() that will later on both be needed by SCTP code. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add two minimal helper functions analogous to time_before() and
time_after() that will later on both be needed by SCTP code.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>