From: Jiang, Yunhong <yunhong.jiang@intel.com>
Date: Fri, 28 Oct 2016 23:29:15 +0000 (+0000)
Subject: Merge "Inform TSC deadline clockevent device about recalibration"
X-Git-Tag: danube.1.0~27
X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=commitdiff_plain;h=ff067418f34c3670cbab67587d8ab0dc0c8f1acc;hp=f2e379228d244be691bee350da1cb3d820cb6dfb;p=kvmfornfv.git

Merge "Inform TSC deadline clockevent device about recalibration"
---

diff --git a/kernel/arch/x86/include/asm/apic.h b/kernel/arch/x86/include/asm/apic.h
index a30316bf8..9686289d2 100644
--- a/kernel/arch/x86/include/asm/apic.h
+++ b/kernel/arch/x86/include/asm/apic.h
@@ -131,6 +131,7 @@ 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
@@ -166,6 +167,7 @@ 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/kernel/arch/x86/kernel/apic/apic.c b/kernel/arch/x86/kernel/apic/apic.c
index d2eee3e1b..58e7cdb25 100644
--- a/kernel/arch/x86/kernel/apic/apic.c
+++ b/kernel/arch/x86/kernel/apic/apic.c
@@ -563,6 +563,30 @@ static void setup_APIC_timer(void)
 		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.
  *
diff --git a/kernel/arch/x86/kernel/tsc.c b/kernel/arch/x86/kernel/tsc.c
index c7c4d9c51..eafe93888 100644
--- a/kernel/arch/x86/kernel/tsc.c
+++ b/kernel/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);
@@ -1141,6 +1142,9 @@ 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:
 	clocksource_register_khz(&clocksource_tsc, tsc_khz);
 }