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# 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();
|
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