Attachment 299226 Details for Bug 438975 – Patch that applies cleanly to 4.6

Patch that applies cleanly to 4.6

linux-2.6-xen-fix-time-going-backwards-gettimeofday.patch (text/x-patch), 1.58 KB, created by Don Dutile (Red Hat) on 2008-03-26 20:41:36 UTC

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Creator: Don Dutile (Red Hat)

Created: 2008-03-26 20:41:36 UTC

Size: 1.58 KB

patch

obsolete

>--- linux-2.6.9/arch/i386/kernel/time-xen.c.orig	2008-03-26 11:20:57.000000000 -0400
>+++ linux-2.6.9/arch/i386/kernel/time-xen.c	2008-03-26 11:47:07.000000000 -0400
>@@ -121,6 +121,9 @@ 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);
>@@ -354,6 +357,7 @@ 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;
>@@ -414,6 +418,17 @@ 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;
> }
>@@ -463,6 +478,12 @@ 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();

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Attachments on bug 438975: 299179 | 299181 | 299213 | 299225 | 299226