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

Pull timer fixes from Ingo Molnar:
 "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"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup
  x86/timers/apic: Inform TSC deadline clockevent device about recalibration
  x86/timers/apic: Fix imprecise timer interrupts by eliminating TSC clockevents frequency roundoff error
  timers: Fix get_next_timer_interrupt() computation
  clocksource/arm_arch_timer: Force per-CPU interrupt to be level-triggered

4 files changed, 33 insertions, 3 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;