X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=kernel%2Fsched_clock.c;h=e1d16c9a76806ef945e4271a9cfcef9ac1a0a0d9;hb=195d1a96ae5fdfbedb8dc4b97afee578921fa99e;hp=390f33234bd007ea41da7006f252e715b6293b43;hpb=cc85906110e26fe8537c3bdbc08a74ae8110030b;p=karo-tx-linux.git

diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 390f33234bd0..e1d16c9a7680 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -25,6 +25,7 @@
  * consistent between cpus (never more than 2 jiffies difference).
  */
 #include <linux/spinlock.h>
+#include <linux/hardirq.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/ktime.h>
@@ -37,7 +38,8 @@
  */
 unsigned long long __attribute__((weak)) sched_clock(void)
 {
-	return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
+	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
+					* (NSEC_PER_SEC / HZ);
 }
 
 static __read_mostly int sched_clock_running;
@@ -154,6 +156,17 @@ u64 sched_clock_cpu(int cpu)
 		return sched_clock();
 
 	scd = cpu_sdc(cpu);
+
+	/*
+	 * Normally this is not called in NMI context - but if it is,
+	 * trying to do any locking here is totally lethal.
+	 */
+	if (unlikely(in_nmi()))
+		return scd->clock;
+
+	if (unlikely(!sched_clock_running))
+		return 0ull;
+
 	WARN_ON_ONCE(!irqs_disabled());
 	now = sched_clock();