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

Pull core timer updates from Ingo Molnar:
 "The main changes in this cycle's merge are:

   - Implement shadow timekeeper to shorten in kernel reader side
     blocking, by Thomas Gleixner.

   - Posix timers enhancements by Pavel Emelyanov:

   - allocate timer ID per process, so that exact timer ID allocations
     can be re-created be checkpoint/restore code.

   - debuggability and tooling (/proc/PID/timers, etc.) improvements.

   - suspend/resume enhancements by Feng Tang: on certain new Intel Atom
     processors (Penwell and Cloverview), there is a feature that the
     TSC won't stop in S3 state, so the TSC value won't be reset to 0
     after resume.  This can be taken advantage of by the generic via
     the CLOCK_SOURCE_SUSPEND_NONSTOP flag: instead of using the RTC to
     recover/approximate sleep time, the main (and precise) clocksource
     can be used.

   - Fix /proc/timer_list for 4096 CPUs by Nathan Zimmer: on so many
     CPUs the file goes beyond 4MB of size and thus the current
     simplistic seqfile approach fails.  Convert /proc/timer_list to a
     proper seq_file with its own iterator.

   - Cleanups and refactorings of the core timekeeping code by John
     Stultz.

   - International Atomic Clock time is managed by the NTP code
     internally currently but not exposed externally.  Separate the TAI
     code out and add CLOCK_TAI support and TAI support to the hrtimer
     and posix-timer code, by John Stultz.

   - Add deep idle support enhacement to the broadcast clockevents core
     timer code, by Daniel Lezcano: add an opt-in CLOCK_EVT_FEAT_DYNIRQ
     clockevents feature (which will be utilized by future clockevents
     driver updates), which allows the use of IRQ affinities to avoid
     spurious wakeups of idle CPUs - the right CPU with an expiring
     timer will be woken.

   - Add new ARM bcm281xx clocksource driver, by Christian Daudt

   - ... various other fixes and cleanups"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  clockevents: Set dummy handler on CPU_DEAD shutdown
  timekeeping: Update tk->cycle_last in resume
  posix-timers: Remove unused variable
  clockevents: Switch into oneshot mode even if broadcast registered late
  timer_list: Convert timer list to be a proper seq_file
  timer_list: Split timer_list_show_tickdevices
  posix-timers: Show sigevent info in proc file
  posix-timers: Introduce /proc/PID/timers file
  posix timers: Allocate timer id per process (v2)
  timekeeping: Make sure to notify hrtimers when TAI offset changes
  hrtimer: Fix ktime_add_ns() overflow on 32bit architectures
  hrtimer: Add expiry time overflow check in hrtimer_interrupt
  timekeeping: Shorten seq_count region
  timekeeping: Implement a shadow timekeeper
  timekeeping: Delay update of clock->cycle_last
  timekeeping: Store cycle_last value in timekeeper struct as well
  ntp: Remove ntp_lock, using the timekeeping locks to protect ntp state
  timekeeping: Simplify tai updating from do_adjtimex
  timekeeping: Hold timekeepering locks in do_adjtimex and hardpps
  timekeeping: Move ADJ_SETOFFSET to top level do_adjtimex()
  ...

diff --cc arch/x86/Kconfig
Simple merge

diff --cc arch/x86/include/asm/cpufeature.h
Simple merge

diff --cc include/linux/sched.h
Simple merge

diff --cc init/main.c
index 12c3669,b3e0614..bea1287
--- 1/init/main.c
--- 2/init/main.c
+++ b/init/main.c
@@@ -495,10 -494,9 +495,9 @@@ asmlinkage void __init start_kernel(voi
   * Interrupts are still disabled. Do necessary setups, then
   * enable them
   */
-       tick_init();
        boot_cpu_init();
        page_address_init();
 -      printk(KERN_NOTICE "%s", linux_banner);
 +      pr_notice("%s", linux_banner);
        setup_arch(&command_line);
        mm_init_owner(&init_mm, &init_task);
        mm_init_cpumask(&init_mm);

diff --cc kernel/cpu/idle.c
index 168cf40,0000000..8b86c0c
mode 100644,000000..100644
--- 1/kernel/cpu/idle.c
--- /dev/null
+++ b/kernel/cpu/idle.c
@@@ -1,107 -1,0 +1,116 @@@
-                       if (cpu_idle_force_poll) {
 +/*
 + * Generic entry point for the idle threads
 + */
 +#include <linux/sched.h>
 +#include <linux/cpu.h>
 +#include <linux/tick.h>
 +#include <linux/mm.h>
 +
 +#include <asm/tlb.h>
 +
 +#include <trace/events/power.h>
 +
 +static int __read_mostly cpu_idle_force_poll;
 +
 +void cpu_idle_poll_ctrl(bool enable)
 +{
 +      if (enable) {
 +              cpu_idle_force_poll++;
 +      } else {
 +              cpu_idle_force_poll--;
 +              WARN_ON_ONCE(cpu_idle_force_poll < 0);
 +      }
 +}
 +
 +#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP
 +static int __init cpu_idle_poll_setup(char *__unused)
 +{
 +      cpu_idle_force_poll = 1;
 +      return 1;
 +}
 +__setup("nohlt", cpu_idle_poll_setup);
 +
 +static int __init cpu_idle_nopoll_setup(char *__unused)
 +{
 +      cpu_idle_force_poll = 0;
 +      return 1;
 +}
 +__setup("hlt", cpu_idle_nopoll_setup);
 +#endif
 +
 +static inline int cpu_idle_poll(void)
 +{
 +      trace_cpu_idle_rcuidle(0, smp_processor_id());
 +      local_irq_enable();
 +      while (!need_resched())
 +              cpu_relax();
 +      trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 +      return 1;
 +}
 +
 +/* Weak implementations for optional arch specific functions */
 +void __weak arch_cpu_idle_prepare(void) { }
 +void __weak arch_cpu_idle_enter(void) { }
 +void __weak arch_cpu_idle_exit(void) { }
 +void __weak arch_cpu_idle_dead(void) { }
 +void __weak arch_cpu_idle(void)
 +{
 +      cpu_idle_force_poll = 1;
 +}
 +
 +/*
 + * Generic idle loop implementation
 + */
 +static void cpu_idle_loop(void)
 +{
 +      while (1) {
 +              tick_nohz_idle_enter();
 +
 +              while (!need_resched()) {
 +                      check_pgt_cache();
 +                      rmb();
 +
 +                      if (cpu_is_offline(smp_processor_id()))
 +                              arch_cpu_idle_dead();
 +
 +                      local_irq_disable();
 +                      arch_cpu_idle_enter();
 +
++                      /*
++                       * In poll mode we reenable interrupts and spin.
++                       *
++                       * Also if we detected in the wakeup from idle
++                       * path that the tick broadcast device expired
++                       * for us, we don't want to go deep idle as we
++                       * know that the IPI is going to arrive right
++                       * away
++                       */
++                      if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
 +                              cpu_idle_poll();
 +                      } else {
 +                              current_clr_polling();
 +                              if (!need_resched()) {
 +                                      stop_critical_timings();
 +                                      rcu_idle_enter();
 +                                      arch_cpu_idle();
 +                                      WARN_ON_ONCE(irqs_disabled());
 +                                      rcu_idle_exit();
 +                                      start_critical_timings();
 +                              } else {
 +                                      local_irq_enable();
 +                              }
 +                              current_set_polling();
 +                      }
 +                      arch_cpu_idle_exit();
 +              }
 +              tick_nohz_idle_exit();
 +              schedule_preempt_disabled();
 +      }
 +}
 +
 +void cpu_startup_entry(enum cpuhp_state state)
 +{
 +      current_set_polling();
 +      arch_cpu_idle_prepare();
 +      cpu_idle_loop();
 +}