# HG changeset patch
# User kfraser@localhost.localdomain
# Date 1182263776 -3600
# Node ID 87bb8705768a66ceabb15a419c5f86580bffb6bf
# Parent a413dd61e7e5e1bba11bab447184cf5e6b43513a
x86 time: Ensure gettimeofday() is monotonically increasing.
Signed-off-by: Atsushi SAKAI <sakaia@jp.fujitsu.com>

Index: linux-2.6.21.i386/arch/i386/kernel/time-xen.c
===================================================================
--- linux-2.6.21.i386.orig/arch/i386/kernel/time-xen.c
+++ linux-2.6.21.i386/arch/i386/kernel/time-xen.c
@@ -107,6 +107,9 @@ static DEFINE_PER_CPU(struct shadow_time
 static struct timespec shadow_tv;
 static u32 shadow_tv_version;
 
+static struct timeval monotonic_tv;
+static spinlock_t monotonic_lock = SPIN_LOCK_UNLOCKED;
+
 /* Keep track of last time we did processing/updating of jiffies and xtime. */
 static u64 processed_system_time;   /* System time (ns) at last processing. */
 static DEFINE_PER_CPU(u64, processed_system_time);
@@ -322,6 +325,7 @@ void do_gettimeofday(struct timeval *tv)
 	unsigned long seq;
 	unsigned long usec, sec;
 	unsigned long max_ntp_tick;
+	unsigned long flags;
 	s64 nsec;
 	unsigned int cpu;
 	struct shadow_time_info *shadow;
@@ -374,6 +378,18 @@ void do_gettimeofday(struct timeval *tv)
 		sec++;
 	}
 
+	spin_lock_irqsave(&monotonic_lock, flags);
+	if ((sec > monotonic_tv.tv_sec) ||
+	    ((sec == monotonic_tv.tv_sec) && (usec > monotonic_tv.tv_usec)))
+	{
+		monotonic_tv.tv_sec = sec;
+		monotonic_tv.tv_usec = usec;
+	} else {
+		sec = monotonic_tv.tv_sec;
+		usec = monotonic_tv.tv_usec;
+	}
+	spin_unlock_irqrestore(&monotonic_lock, flags);
+
 	tv->tv_sec = sec;
 	tv->tv_usec = usec;
 }
@@ -423,6 +439,12 @@ int do_settimeofday(struct timespec *tv)
 		__update_wallclock(sec, nsec);
 	}
 
+	/* Reset monotonic gettimeofday() timeval. */
+	spin_lock(&monotonic_lock);
+	monotonic_tv.tv_sec = 0;
+	monotonic_tv.tv_usec = 0;
+	spin_unlock(&monotonic_lock);
+
 	write_sequnlock_irq(&xtime_lock);
 
 	put_cpu();