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-rw-r--r--kernel/sysctl_check.c1
-rw-r--r--kernel/time/Makefile2
-rw-r--r--kernel/time/clocksource.c76
-rw-r--r--kernel/time/timecompare.c191
4 files changed, 269 insertions, 1 deletions
diff --git a/kernel/sysctl_check.c b/kernel/sysctl_check.c
index fafeb48f27c..b38423ca711 100644
--- a/kernel/sysctl_check.c
+++ b/kernel/sysctl_check.c
@@ -219,6 +219,7 @@ static const struct trans_ctl_table trans_net_ipv4_conf_vars_table[] = {
{ NET_IPV4_CONF_ARP_IGNORE, "arp_ignore" },
{ NET_IPV4_CONF_PROMOTE_SECONDARIES, "promote_secondaries" },
{ NET_IPV4_CONF_ARP_ACCEPT, "arp_accept" },
+ { NET_IPV4_CONF_ARP_NOTIFY, "arp_notify" },
{}
};
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index 905b0b50792..0b0a6366c9d 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1,4 +1,4 @@
-obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
+obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD) += clockevents.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index ca89e1593f0..c46c931a7fe 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -31,6 +31,82 @@
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
+void timecounter_init(struct timecounter *tc,
+ const struct cyclecounter *cc,
+ u64 start_tstamp)
+{
+ tc->cc = cc;
+ tc->cycle_last = cc->read(cc);
+ tc->nsec = start_tstamp;
+}
+EXPORT_SYMBOL(timecounter_init);
+
+/**
+ * timecounter_read_delta - get nanoseconds since last call of this function
+ * @tc: Pointer to time counter
+ *
+ * When the underlying cycle counter runs over, this will be handled
+ * correctly as long as it does not run over more than once between
+ * calls.
+ *
+ * The first call to this function for a new time counter initializes
+ * the time tracking and returns an undefined result.
+ */
+static u64 timecounter_read_delta(struct timecounter *tc)
+{
+ cycle_t cycle_now, cycle_delta;
+ u64 ns_offset;
+
+ /* read cycle counter: */
+ cycle_now = tc->cc->read(tc->cc);
+
+ /* calculate the delta since the last timecounter_read_delta(): */
+ cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;
+
+ /* convert to nanoseconds: */
+ ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta);
+
+ /* update time stamp of timecounter_read_delta() call: */
+ tc->cycle_last = cycle_now;
+
+ return ns_offset;
+}
+
+u64 timecounter_read(struct timecounter *tc)
+{
+ u64 nsec;
+
+ /* increment time by nanoseconds since last call */
+ nsec = timecounter_read_delta(tc);
+ nsec += tc->nsec;
+ tc->nsec = nsec;
+
+ return nsec;
+}
+EXPORT_SYMBOL(timecounter_read);
+
+u64 timecounter_cyc2time(struct timecounter *tc,
+ cycle_t cycle_tstamp)
+{
+ u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
+ u64 nsec;
+
+ /*
+ * Instead of always treating cycle_tstamp as more recent
+ * than tc->cycle_last, detect when it is too far in the
+ * future and treat it as old time stamp instead.
+ */
+ if (cycle_delta > tc->cc->mask / 2) {
+ cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
+ nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta);
+ } else {
+ nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec;
+ }
+
+ return nsec;
+}
+EXPORT_SYMBOL(timecounter_cyc2time);
+
/* XXX - Would like a better way for initializing curr_clocksource */
extern struct clocksource clocksource_jiffies;
diff --git a/kernel/time/timecompare.c b/kernel/time/timecompare.c
new file mode 100644
index 00000000000..71e7f1a1915
--- /dev/null
+++ b/kernel/time/timecompare.c
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2009 Intel Corporation.
+ * Author: Patrick Ohly <patrick.ohly@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/timecompare.h>
+#include <linux/module.h>
+#include <linux/math64.h>
+
+/*
+ * fixed point arithmetic scale factor for skew
+ *
+ * Usually one would measure skew in ppb (parts per billion, 1e9), but
+ * using a factor of 2 simplifies the math.
+ */
+#define TIMECOMPARE_SKEW_RESOLUTION (((s64)1)<<30)
+
+ktime_t timecompare_transform(struct timecompare *sync,
+ u64 source_tstamp)
+{
+ u64 nsec;
+
+ nsec = source_tstamp + sync->offset;
+ nsec += (s64)(source_tstamp - sync->last_update) * sync->skew /
+ TIMECOMPARE_SKEW_RESOLUTION;
+
+ return ns_to_ktime(nsec);
+}
+EXPORT_SYMBOL(timecompare_transform);
+
+int timecompare_offset(struct timecompare *sync,
+ s64 *offset,
+ u64 *source_tstamp)
+{
+ u64 start_source = 0, end_source = 0;
+ struct {
+ s64 offset;
+ s64 duration_target;
+ } buffer[10], sample, *samples;
+ int counter = 0, i;
+ int used;
+ int index;
+ int num_samples = sync->num_samples;
+
+ if (num_samples > sizeof(buffer)/sizeof(buffer[0])) {
+ samples = kmalloc(sizeof(*samples) * num_samples, GFP_ATOMIC);
+ if (!samples) {
+ samples = buffer;
+ num_samples = sizeof(buffer)/sizeof(buffer[0]);
+ }
+ } else {
+ samples = buffer;
+ }
+
+ /* run until we have enough valid samples, but do not try forever */
+ i = 0;
+ counter = 0;
+ while (1) {
+ u64 ts;
+ ktime_t start, end;
+
+ start = sync->target();
+ ts = timecounter_read(sync->source);
+ end = sync->target();
+
+ if (!i)
+ start_source = ts;
+
+ /* ignore negative durations */
+ sample.duration_target = ktime_to_ns(ktime_sub(end, start));
+ if (sample.duration_target >= 0) {
+ /*
+ * assume symetric delay to and from source:
+ * average target time corresponds to measured
+ * source time
+ */
+ sample.offset =
+ ktime_to_ns(ktime_add(end, start)) / 2 -
+ ts;
+
+ /* simple insertion sort based on duration */
+ index = counter - 1;
+ while (index >= 0) {
+ if (samples[index].duration_target <
+ sample.duration_target)
+ break;
+ samples[index + 1] = samples[index];
+ index--;
+ }
+ samples[index + 1] = sample;
+ counter++;
+ }
+
+ i++;
+ if (counter >= num_samples || i >= 100000) {
+ end_source = ts;
+ break;
+ }
+ }
+
+ *source_tstamp = (end_source + start_source) / 2;
+
+ /* remove outliers by only using 75% of the samples */
+ used = counter * 3 / 4;
+ if (!used)
+ used = counter;
+ if (used) {
+ /* calculate average */
+ s64 off = 0;
+ for (index = 0; index < used; index++)
+ off += samples[index].offset;
+ *offset = div_s64(off, used);
+ }
+
+ if (samples && samples != buffer)
+ kfree(samples);
+
+ return used;
+}
+EXPORT_SYMBOL(timecompare_offset);
+
+void __timecompare_update(struct timecompare *sync,
+ u64 source_tstamp)
+{
+ s64 offset;
+ u64 average_time;
+
+ if (!timecompare_offset(sync, &offset, &average_time))
+ return;
+
+ if (!sync->last_update) {
+ sync->last_update = average_time;
+ sync->offset = offset;
+ sync->skew = 0;
+ } else {
+ s64 delta_nsec = average_time - sync->last_update;
+
+ /* avoid division by negative or small deltas */
+ if (delta_nsec >= 10000) {
+ s64 delta_offset_nsec = offset - sync->offset;
+ s64 skew; /* delta_offset_nsec *
+ TIMECOMPARE_SKEW_RESOLUTION /
+ delta_nsec */
+ u64 divisor;
+
+ /* div_s64() is limited to 32 bit divisor */
+ skew = delta_offset_nsec * TIMECOMPARE_SKEW_RESOLUTION;
+ divisor = delta_nsec;
+ while (unlikely(divisor >= ((s64)1) << 32)) {
+ /* divide both by 2; beware, right shift
+ of negative value has undefined
+ behavior and can only be used for
+ the positive divisor */
+ skew = div_s64(skew, 2);
+ divisor >>= 1;
+ }
+ skew = div_s64(skew, divisor);
+
+ /*
+ * Calculate new overall skew as 4/16 the
+ * old value and 12/16 the new one. This is
+ * a rather arbitrary tradeoff between
+ * only using the latest measurement (0/16 and
+ * 16/16) and even more weight on past measurements.
+ */
+#define TIMECOMPARE_NEW_SKEW_PER_16 12
+ sync->skew =
+ div_s64((16 - TIMECOMPARE_NEW_SKEW_PER_16) *
+ sync->skew +
+ TIMECOMPARE_NEW_SKEW_PER_16 * skew,
+ 16);
+ sync->last_update = average_time;
+ sync->offset = offset;
+ }
+ }
+}
+EXPORT_SYMBOL(__timecompare_update);
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-23 23:57:10 +0000