[GIT PULL] timer fixes

[Ingo Molnar <mingo@kernel.org>]

Linus,

Please pull the latest timers-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus

   # HEAD: 22cc1ca3c5469cf17e149be232817b9223afa5e4 x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup

Misc fixes: a /dev/rtc regression fix, two APIC timer period calibration fixes, an 
ARM clocksource driver fix and a NOHZ power use regression fix.

 Thanks,

	Ingo

------------------>
Arnd Bergmann (1):
      x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup

Chris Metcalf (1):
      timers: Fix get_next_timer_interrupt() computation

Marc Zyngier (1):
      clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered

Nicolai Stange (2):
      x86/timers/apic: Fix imprecise timer interrupts by eliminating TSC clockevents frequency roundoff error
      x86/timers/apic: Inform TSC deadline clockevent device about recalibration


 arch/x86/include/asm/apic.h          |  2 ++
 arch/x86/kernel/apic/apic.c          | 28 ++++++++++++++++++++++++++--
 arch/x86/kernel/hpet.c               |  2 +-
 arch/x86/kernel/tsc.c                |  4 ++++
 drivers/clocksource/arm_arch_timer.c | 26 +++++++++++++++++++++++---
 kernel/time/timer.c                  |  5 ++++-
 6 files changed, 60 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index f5befd4945f2..124357773ffa 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -135,6 +135,7 @@ extern void init_apic_mappings(void);
 void register_lapic_address(unsigned long address);
 extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
+extern void lapic_update_tsc_freq(void);
 extern int APIC_init_uniprocessor(void);
 
 #ifdef CONFIG_X86_64
@@ -170,6 +171,7 @@ static inline void init_apic_mappings(void) { }
 static inline void disable_local_APIC(void) { }
 # define setup_boot_APIC_clock x86_init_noop
 # define setup_secondary_APIC_clock x86_init_noop
+static inline void lapic_update_tsc_freq(void) { }
 #endif /* !CONFIG_X86_LOCAL_APIC */
 
 #ifdef CONFIG_X86_X2APIC
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 20abd912f0e4..cea4fc19e844 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -313,7 +313,7 @@ int lapic_get_maxlvt(void)
 
 /* Clock divisor */
 #define APIC_DIVISOR 16
-#define TSC_DIVISOR  32
+#define TSC_DIVISOR  8
 
 /*
  * This function sets up the local APIC timer, with a timeout of
@@ -565,13 +565,37 @@ static void setup_APIC_timer(void)
 				    CLOCK_EVT_FEAT_DUMMY);
 		levt->set_next_event = lapic_next_deadline;
 		clockevents_config_and_register(levt,
-						(tsc_khz / TSC_DIVISOR) * 1000,
+						tsc_khz * (1000 / TSC_DIVISOR),
 						0xF, ~0UL);
 	} else
 		clockevents_register_device(levt);
 }
 
 /*
+ * Install the updated TSC frequency from recalibration at the TSC
+ * deadline clockevent devices.
+ */
+static void __lapic_update_tsc_freq(void *info)
+{
+	struct clock_event_device *levt = this_cpu_ptr(&lapic_events);
+
+	if (!this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
+		return;
+
+	clockevents_update_freq(levt, tsc_khz * (1000 / TSC_DIVISOR));
+}
+
+void lapic_update_tsc_freq(void)
+{
+	/*
+	 * The clockevent device's ->mult and ->shift can both be
+	 * changed. In order to avoid races, schedule the frequency
+	 * update code on each CPU.
+	 */
+	on_each_cpu(__lapic_update_tsc_freq, NULL, 0);
+}
+
+/*
  * In this functions we calibrate APIC bus clocks to the external timer.
  *
  * We want to do the calibration only once since we want to have local timer
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index ed16e58658a4..c6dfd801df97 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -1242,7 +1242,7 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 	memset(&curr_time, 0, sizeof(struct rtc_time));
 
 	if (hpet_rtc_flags & (RTC_UIE | RTC_AIE))
-		mc146818_set_time(&curr_time);
+		mc146818_get_time(&curr_time);
 
 	if (hpet_rtc_flags & RTC_UIE &&
 	    curr_time.tm_sec != hpet_prev_update_sec) {
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 1ef87e887051..78b9cb5a26af 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -22,6 +22,7 @@
 #include <asm/nmi.h>
 #include <asm/x86_init.h>
 #include <asm/geode.h>
+#include <asm/apic.h>
 
 unsigned int __read_mostly cpu_khz;	/* TSC clocks / usec, not used here */
 EXPORT_SYMBOL(cpu_khz);
@@ -1249,6 +1250,9 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 		(unsigned long)tsc_khz / 1000,
 		(unsigned long)tsc_khz % 1000);
 
+	/* Inform the TSC deadline clockevent devices about the recalibration */
+	lapic_update_tsc_freq();
+
 out:
 	if (boot_cpu_has(X86_FEATURE_ART))
 		art_related_clocksource = &clocksource_tsc;
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 28bce3f4f81d..57700541f951 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -8,6 +8,9 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+
+#define pr_fmt(fmt)	"arm_arch_timer: " fmt
+
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
@@ -370,16 +373,33 @@ static bool arch_timer_has_nonsecure_ppi(void)
 		arch_timer_ppi[PHYS_NONSECURE_PPI]);
 }
 
+static u32 check_ppi_trigger(int irq)
+{
+	u32 flags = irq_get_trigger_type(irq);
+
+	if (flags != IRQF_TRIGGER_HIGH && flags != IRQF_TRIGGER_LOW) {
+		pr_warn("WARNING: Invalid trigger for IRQ%d, assuming level low\n", irq);
+		pr_warn("WARNING: Please fix your firmware\n");
+		flags = IRQF_TRIGGER_LOW;
+	}
+
+	return flags;
+}
+
 static int arch_timer_starting_cpu(unsigned int cpu)
 {
 	struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
+	u32 flags;
 
 	__arch_timer_setup(ARCH_CP15_TIMER, clk);
 
-	enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], 0);
+	flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]);
+	enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags);
 
-	if (arch_timer_has_nonsecure_ppi())
-		enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
+	if (arch_timer_has_nonsecure_ppi()) {
+		flags = check_ppi_trigger(arch_timer_ppi[PHYS_NONSECURE_PPI]);
+		enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], flags);
+	}
 
 	arch_counter_set_user_access();
 	if (evtstrm_enable)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 555670a5143c..32bf6f75a8fe 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1496,6 +1496,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
 	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
 	u64 expires = KTIME_MAX;
 	unsigned long nextevt;
+	bool is_max_delta;
 
 	/*
 	 * Pretend that there is no timer pending if the cpu is offline.
@@ -1506,6 +1507,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
 
 	spin_lock(&base->lock);
 	nextevt = __next_timer_interrupt(base);
+	is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA);
 	base->next_expiry = nextevt;
 	/*
 	 * We have a fresh next event. Check whether we can forward the base:
@@ -1519,7 +1521,8 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
 		expires = basem;
 		base->is_idle = false;
 	} else {
-		expires = basem + (nextevt - basej) * TICK_NSEC;
+		if (!is_max_delta)
+			expires = basem + (nextevt - basej) * TICK_NSEC;
 		/*
 		 * If we expect to sleep more than a tick, mark the base idle:
 		 */