linux-stable.git/drivers/rtc/interface.c, branch linux-4.19.y

rtc: check if __rtc_read_time was successful in rtc_timer_do_work()

2024-12-05T09:59:41+00:00

[ Upstream commit e8ba8a2bc4f60a1065f23d6a0e7cbea945a0f40d ]

If the __rtc_read_time call fails,, the struct rtc_time tm; may contain
uninitialized data, or an illegal date/time read from the RTC hardware.

When calling rtc_tm_to_ktime later, the result may be a very large value
(possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue,
they will continually expire, may causing kernel softlockup.

Fixes: 6610e0893b8b ("RTC: Rework RTC code to use timerqueue for events")
Signed-off-by: Yongliang Gao 
Acked-by: Jingqun Li 
Link: https://lore.kernel.org/r/20241011043153.3788112-1-leonylgao@gmail.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

rtc: disable uie before setting time and enable after

2019-12-17T19:35:43+00:00

commit 7e7c005b4b1f1f169bcc4b2c3a40085ecc663df2 upstream.

When setting the time in the future with the uie timer enabled,
rtc_timer_do_work will loop for a while because the expiration of the uie
timer was way before the current RTC time and a new timer will be enqueued
until the current rtc time is reached.

If the uie timer is enabled, disable it before setting the time and enable
it after expiring current timers (which may actually be an alarm).

This is the safest thing to do to ensure the uie timer is still
synchronized with the RTC, especially in the UIE emulation case.

Reported-by: syzbot+08116743f8ad6f9a6de7@syzkaller.appspotmail.com
Fixes: 6610e0893b8b ("RTC: Rework RTC code to use timerqueue for events")
Link: https://lore.kernel.org/r/20191020231320.8191-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'rtc-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2018-08-20T23:30:27+00:00

Pull RTC updates from Alexandre Belloni:
 "It is now possible to add custom sysfs attributes while avoiding a
  possible race condition. Unused code has been removed resulting in a
  nice reduction of the code base. And more drivers have been switched
  to SPDX by their maintainers.

 Summary:

  Subsystem:
   - new helpers to add custom sysfs attributes
   - struct rtc_task removal along with rtc_irq_[un]register()
   - rtc_irq_set_state and rtc_irq_set_freq are not exported anymore

  Drivers:
   - armada38x: reset after rtc power loss
   - ds1307: now supports m41t11
   - isl1208: now supports isl1219 and tamper detection
   - pcf2127: internal SRAM support"

* tag 'rtc-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (34 commits)
  rtc: ds1307: simplify hwmon config
  rtc: s5m: Add SPDX license identifier
  rtc: maxim: Add SPDX license identifiers
  rtc: isl1219: add device tree documentation
  rtc: isl1208: set ev-evienb bit from device tree
  rtc: isl1208: Add "evdet" interrupt source for isl1219
  rtc: isl1208: add support for isl1219 with tamper detection
  rtc: sysfs: facilitate attribute add to rtc device
  rtc: remove struct rtc_task
  char: rtc: remove task handling
  rtc: pcf85063: preserve control register value between stop and start
  rtc: sh: remove unused variable rtc_dev
  rtc: unexport rtc_irq_set_*
  rtc: simplify rtc_irq_set_state/rtc_irq_set_freq
  rtc: remove irq_task and irq_task_lock
  rtc: remove rtc_irq_register/rtc_irq_unregister
  rtc: sh: remove dead code
  rtc: sa1100: don't set PIE frequency
  rtc: ds1307: support m41t11 variant
  rtc: ds1307: fix data pointer to m41t0
  ...

rtc: remove struct rtc_task

2018-08-02T15:16:05+00:00

Include rtc_task members directly in rtc_timer member.

Signed-off-by: Alexandre Belloni

rtc: unexport rtc_irq_set_*

2018-07-26T13:08:53+00:00

Make the rtc_irq_set interface internale to the RTC subsystem.

Signed-off-by: Alexandre Belloni

rtc: simplify rtc_irq_set_state/rtc_irq_set_freq

2018-07-26T13:08:53+00:00

The PIE doesn't handle tasks anymore, remove the pointer from the
interface.

Signed-off-by: Alexandre Belloni

rtc: remove irq_task and irq_task_lock

2018-07-26T13:08:53+00:00

There is no way to set a periodic task anymore, remove task pointer and
lock.

Signed-off-by: Alexandre Belloni

rtc: remove rtc_irq_register/rtc_irq_unregister

2018-07-26T13:08:50+00:00

The rtc_irq_* interface is not used from outside the RTC subsytem since
2016.

Signed-off-by: Alexandre Belloni

rtc: fix alarm read and set offset

2018-07-13T08:37:54+00:00

The offset needs to be added after reading the alarm value.

It also needs to be subtracted after the now < alarm test.

Tested-by: Jon Hunter 
Signed-off-by: Alexandre Belloni

rtc: ensure rtc_set_alarm fails when alarms are not supported

2018-06-07T18:09:49+00:00

When using RTC_ALM_SET or RTC_WKALM_SET with rtc_wkalrm.enabled not set,
rtc_timer_enqueue() is not called and rtc_set_alarm() may succeed but the
subsequent RTC_AIE_ON ioctl will fail. RTC_ALM_READ would also fail in that
case.

Ensure rtc_set_alarm() fails when alarms are not supported to avoid letting
programs think the alarms are working for a particular RTC when they are
not.

Signed-off-by: Alexandre Belloni