linux.git/drivers/rtc, branch v3.1-rc3

Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-08-17T17:28:33+00:00

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rtc: Limit RTC PIE frequency
  rtc: Fix hrtimer deadlock
  rtc: Handle errors correctly in rtc_irq_set_state()

Fixup trivial conflicts in drivers/rtc/interface.c due to slightly
trivially versions of the same patch coming in two different ways.

rtc-omap: fix initialization of control register

2011-08-04T00:25:20+00:00

As the comment explains, the intention of the code is to clear the
OMAP_RTC_CTRL_MODE_12_24 bit, but instead it only clears the
OMAP_RTC_CTRL_SPLIT and OMAP_RTC_CTRL_AUTO_COMP bits, which should be
kept.  OMAP_RTC_CTRL_DISABLE, OMAP_RTC_CTRL_SET_32_COUNTER,
OMAP_RTC_CTRL_TEST, and OMAP_RTC_CTRL_ROUND_30S are also better off
being cleared.

Signed-off-by: Daniel Glöckner 
Cc: Alessandro Zummo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: fix hrtimer deadlock

2011-07-26T23:49:42+00:00

Ben reported a lockup related to rtc. The lockup happens due to:

CPU0                                        CPU1

rtc_irq_set_state()			    __run_hrtimer()
  spin_lock_irqsave(&rtc->irq_task_lock)    rtc_handle_legacy_irq();
					      spin_lock(&rtc->irq_task_lock);
  hrtimer_cancel()
    while (callback_running);

So the running callback never finishes as it's blocked on
rtc->irq_task_lock.

Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback.  Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().

Signed-off-by: Thomas Gleixner 
Reported-by: Ben Greear 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: limit frequency

2011-07-26T23:49:42+00:00

Due to the hrtimer self rearming mode a user can DoS the machine simply
because it's starved by hrtimer events.

The RTC hrtimer is self rearming.  We really need to limit the frequency
to something sensible.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Ben Greear 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: handle errors correctly in rtc_irq_set_state()

2011-07-26T23:49:41+00:00

The code checks the correctness of the parameters, but unconditionally
arms/disarms the hrtimer.

The result is that a random task might arm/disarm rtc timer and surprise
the real owner by either generating events or by stopping them.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Ben Greear 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: Limit RTC PIE frequency

2011-07-26T21:50:01+00:00

The RTC pie hrtimer is self rearming. We really need to limit the
frequency to something sensible. Thus limit it to the 8192Hz max
value from the rtc man documentation

Cc: Willy Tarreau 
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner 
[jstultz: slightly reworked to use RTC_MAX_FREQ value]
Signed-off-by: John Stultz

rtc: Fix hrtimer deadlock

2011-07-26T21:49:59+00:00

Ben reported a lockup related to rtc. The lockup happens due to:

CPU0                                        CPU1

rtc_irq_set_state()			    __run_hrtimer()
  spin_lock_irqsave(&rtc->irq_task_lock)    rtc_handle_legacy_irq();
					      spin_lock(&rtc->irq_task_lock);
  hrtimer_cancel()
    while (callback_running);

So the running callback never finishes as it's blocked on
rtc->irq_task_lock.

Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback. Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().

Cc: stable@kernel.org
Reported-by: Ben Greear 
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz

rtc: Handle errors correctly in rtc_irq_set_state()

2011-07-26T21:49:57+00:00

In rtc_irq_set_state, the code checks the correctness of the parameters,
but then goes on to unconditionally arms/disarms the hrtimer. Thus a
random task might arm/disarm rtc timer and surprise the real owner by
either generating events or by stopping them.

Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz

Merge 'akpm' patch series

2011-07-26T04:00:19+00:00

* Merge akpm patch series: (122 commits)
  drivers/connector/cn_proc.c: remove unused local
  Documentation/SubmitChecklist: add RCU debug config options
  reiserfs: use hweight_long()
  reiserfs: use proper little-endian bitops
  pnpacpi: register disabled resources
  drivers/rtc/rtc-tegra.c: properly initialize spinlock
  drivers/rtc/rtc-twl.c: check return value of twl_rtc_write_u8() in twl_rtc_set_time()
  drivers/rtc: add support for Qualcomm PMIC8xxx RTC
  drivers/rtc/rtc-s3c.c: support clock gating
  drivers/rtc/rtc-mpc5121.c: add support for RTC on MPC5200
  init: skip calibration delay if previously done
  misc/eeprom: add eeprom access driver for digsy_mtc board
  misc/eeprom: add driver for microwire 93xx46 EEPROMs
  checkpatch.pl: update $logFunctions
  checkpatch: make utf-8 test --strict
  checkpatch.pl: add ability to ignore various messages
  checkpatch: add a "prefer __aligned" check
  checkpatch: validate signature styles and To: and Cc: lines
  checkpatch: add __rcu as a sparse modifier
  checkpatch: suggest using min_t or max_t
  ...

Did this as a merge because of (trivial) conflicts in
 - Documentation/feature-removal-schedule.txt
 - arch/xtensa/include/asm/uaccess.h
that were just easier to fix up in the merge than in the patch series.

drivers/rtc/rtc-tegra.c: properly initialize spinlock

2011-07-26T03:57:17+00:00

Using __SPIN_LOCK_UNLOCKED for a dynamically allocated lock is wrong and
breaks the build with PREEMPT_RT_FULL.

Signed-off-by: Uwe Kleine-König 
Cc: Andrew Chew 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds