Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer and time updates from Thomas Gleixner:
 "A rather large update of timers, timekeeping & co

   - Core timekeeping code is year-2038 safe now for 32bit machines.
     Now we just need to fix all in kernel users and the gazillion of
     user space interfaces which rely on timespec/timeval :)

   - Better cache layout for the timekeeping internal data structures.

   - Proper nanosecond based interfaces for in kernel users.

   - Tree wide cleanup of code which wants nanoseconds but does hoops
     and loops to convert back and forth from timespecs.  Some of it
     definitely belongs into the ugly code museum.

   - Consolidation of the timekeeping interface zoo.

   - A fast NMI safe accessor to clock monotonic for tracing.  This is a
     long standing request to support correlated user/kernel space
     traces.  With proper NTP frequency correction it's also suitable
     for correlation of traces accross separate machines.

   - Checkpoint/restart support for timerfd.

   - A few NOHZ[_FULL] improvements in the [hr]timer code.

   - Code move from kernel to kernel/time of all time* related code.

   - New clocksource/event drivers from the ARM universe.  I'm really
     impressed that despite an architected timer in the newer chips SoC
     manufacturers insist on inventing new and differently broken SoC
     specific timers.

[ Ed. "Impressed"? I don't think that word means what you think it means ]

   - Another round of code move from arch to drivers.  Looks like most
     of the legacy mess in ARM regarding timers is sorted out except for
     a few obnoxious strongholds.

   - The usual updates and fixlets all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  timekeeping: Fixup typo in update_vsyscall_old definition
  clocksource: document some basic timekeeping concepts
  timekeeping: Use cached ntp_tick_length when accumulating error
  timekeeping: Rework frequency adjustments to work better w/ nohz
  timekeeping: Minor fixup for timespec64->timespec assignment
  ftrace: Provide trace clocks monotonic
  timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC
  seqcount: Add raw_write_seqcount_latch()
  seqcount: Provide raw_read_seqcount()
  timekeeping: Use tk_read_base as argument for timekeeping_get_ns()
  timekeeping: Create struct tk_read_base and use it in struct timekeeper
  timekeeping: Restructure the timekeeper some more
  clocksource: Get rid of cycle_last
  clocksource: Move cycle_last validation to core code
  clocksource: Make delta calculation a function
  wireless: ath9k: Get rid of timespec conversions
  drm: vmwgfx: Use nsec based interfaces
  drm: i915: Use nsec based interfaces
  timekeeping: Provide ktime_get_raw()
  hangcheck-timer: Use ktime_get_ns()
  ...

kernel/time/Kconfig

@@ -12,6 +12,11 @@ config CLOCKSOURCE_WATCHDOG
 config ARCH_CLOCKSOURCE_DATA
 	bool
 
+# Clocksources require validation of the clocksource against the last
+# cycle update - x86/TSC misfeature
+config CLOCKSOURCE_VALIDATE_LAST_CYCLE
+	bool
+
 # Timekeeping vsyscall support
 config GENERIC_TIME_VSYSCALL
 	bool
@@ -20,10 +25,6 @@ config GENERIC_TIME_VSYSCALL
 config GENERIC_TIME_VSYSCALL_OLD
 	bool
 
-# ktime_t scalar 64bit nsec representation
-config KTIME_SCALAR
-	bool
-
 # Old style timekeeping
 config ARCH_USES_GETTIMEOFFSET
 	bool

kernel/time/Makefile

@@ -1,3 +1,4 @@
+obj-y += time.o timer.o hrtimer.o itimer.o posix-timers.o posix-cpu-timers.o
 obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
 obj-y += timeconv.o posix-clock.o alarmtimer.o
 
@@ -12,3 +13,21 @@ obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-sched.o
 obj-$(CONFIG_TIMER_STATS)			+= timer_stats.o
 obj-$(CONFIG_DEBUG_FS)				+= timekeeping_debug.o
+obj-$(CONFIG_TEST_UDELAY)			+= udelay_test.o
+
+$(obj)/time.o: $(obj)/timeconst.h
+
+quiet_cmd_hzfile = HZFILE  $@
+      cmd_hzfile = echo "hz=$(CONFIG_HZ)" > $@
+
+targets += hz.bc
+$(obj)/hz.bc: $(objtree)/include/config/hz.h FORCE
+	$(call if_changed,hzfile)
+
+quiet_cmd_bc  = BC      $@
+      cmd_bc  = bc -q $(filter-out FORCE,$^) > $@
+
+targets += timeconst.h
+$(obj)/timeconst.h: $(obj)/hz.bc $(src)/timeconst.bc FORCE
+	$(call if_changed,bc)
+

kernel/time/clocksource.c

@@ -32,6 +32,7 @@
 #include <linux/kthread.h>
 
 #include "tick-internal.h"
+#include "timekeeping_internal.h"
 
 void timecounter_init(struct timecounter *tc,
 		      const struct cyclecounter *cc,
@@ -249,7 +250,7 @@ void clocksource_mark_unstable(struct clocksource *cs)
 static void clocksource_watchdog(unsigned long data)
 {
 	struct clocksource *cs;
-	cycle_t csnow, wdnow;
+	cycle_t csnow, wdnow, delta;
 	int64_t wd_nsec, cs_nsec;
 	int next_cpu, reset_pending;
 
@@ -282,11 +283,12 @@ static void clocksource_watchdog(unsigned long data)
 			continue;
 		}
 
-		wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask,
-					     watchdog->mult, watchdog->shift);
+		delta = clocksource_delta(wdnow, cs->wd_last, watchdog->mask);
+		wd_nsec = clocksource_cyc2ns(delta, watchdog->mult,
+					     watchdog->shift);
 
-		cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) &
-					     cs->mask, cs->mult, cs->shift);
+		delta = clocksource_delta(csnow, cs->cs_last, cs->mask);
+		cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift);
 		cs->cs_last = csnow;
 		cs->wd_last = wdnow;
 

kernel/time/itimer.c

@@ -0,0 +1,301 @@
+/*
+ * linux/kernel/itimer.c
+ *
+ * Copyright (C) 1992 Darren Senn
+ */
+
+/* These are all the functions necessary to implement itimers */
+
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/syscalls.h>
+#include <linux/time.h>
+#include <linux/posix-timers.h>
+#include <linux/hrtimer.h>
+#include <trace/events/timer.h>
+
+#include <asm/uaccess.h>
+
+/**
+ * itimer_get_remtime - get remaining time for the timer
+ *
+ * @timer: the timer to read
+ *
+ * Returns the delta between the expiry time and now, which can be
+ * less than zero or 1usec for an pending expired timer
+ */
+static struct timeval itimer_get_remtime(struct hrtimer *timer)
+{
+	ktime_t rem = hrtimer_get_remaining(timer);
+
+	/*
+	 * Racy but safe: if the itimer expires after the above
+	 * hrtimer_get_remtime() call but before this condition
+	 * then we return 0 - which is correct.
+	 */
+	if (hrtimer_active(timer)) {
+		if (rem.tv64 <= 0)
+			rem.tv64 = NSEC_PER_USEC;
+	} else
+		rem.tv64 = 0;
+
+	return ktime_to_timeval(rem);
+}
+
+static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+			   struct itimerval *const value)
+{
+	cputime_t cval, cinterval;
+	struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+	spin_lock_irq(&tsk->sighand->siglock);
+
+	cval = it->expires;
+	cinterval = it->incr;
+	if (cval) {
+		struct task_cputime cputime;
+		cputime_t t;
+
+		thread_group_cputimer(tsk, &cputime);
+		if (clock_id == CPUCLOCK_PROF)
+			t = cputime.utime + cputime.stime;
+		else
+			/* CPUCLOCK_VIRT */
+			t = cputime.utime;
+
+		if (cval < t)
+			/* about to fire */
+			cval = cputime_one_jiffy;
+		else
+			cval = cval - t;
+	}
+
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	cputime_to_timeval(cval, &value->it_value);
+	cputime_to_timeval(cinterval, &value->it_interval);
+}
+
+int do_getitimer(int which, struct itimerval *value)
+{
+	struct task_struct *tsk = current;
+
+	switch (which) {
+	case ITIMER_REAL:
+		spin_lock_irq(&tsk->sighand->siglock);
+		value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
+		value->it_interval =
+			ktime_to_timeval(tsk->signal->it_real_incr);
+		spin_unlock_irq(&tsk->sighand->siglock);
+		break;
+	case ITIMER_VIRTUAL:
+		get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
+		break;
+	case ITIMER_PROF:
+		get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
+		break;
+	default:
+		return(-EINVAL);
+	}
+	return 0;
+}
+
+SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
+{
+	int error = -EFAULT;
+	struct itimerval get_buffer;
+
+	if (value) {
+		error = do_getitimer(which, &get_buffer);
+		if (!error &&
+		    copy_to_user(value, &get_buffer, sizeof(get_buffer)))
+			error = -EFAULT;
+	}
+	return error;
+}
+
+
+/*
+ * The timer is automagically restarted, when interval != 0
+ */
+enum hrtimer_restart it_real_fn(struct hrtimer *timer)
+{
+	struct signal_struct *sig =
+		container_of(timer, struct signal_struct, real_timer);
+
+	trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
+	kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
+
+	return HRTIMER_NORESTART;
+}
+
+static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
+{
+	struct timespec ts;
+	s64 cpu_ns;
+
+	cputime_to_timespec(ct, &ts);
+	cpu_ns = timespec_to_ns(&ts);
+
+	return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
+}
+
+static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+			   const struct itimerval *const value,
+			   struct itimerval *const ovalue)
+{
+	cputime_t cval, nval, cinterval, ninterval;
+	s64 ns_ninterval, ns_nval;
+	u32 error, incr_error;
+	struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+	nval = timeval_to_cputime(&value->it_value);
+	ns_nval = timeval_to_ns(&value->it_value);
+	ninterval = timeval_to_cputime(&value->it_interval);
+	ns_ninterval = timeval_to_ns(&value->it_interval);
+
+	error = cputime_sub_ns(nval, ns_nval);
+	incr_error = cputime_sub_ns(ninterval, ns_ninterval);
+
+	spin_lock_irq(&tsk->sighand->siglock);
+
+	cval = it->expires;
+	cinterval = it->incr;
+	if (cval || nval) {
+		if (nval > 0)
+			nval += cputime_one_jiffy;
+		set_process_cpu_timer(tsk, clock_id, &nval, &cval);
+	}
+	it->expires = nval;
+	it->incr = ninterval;
+	it->error = error;
+	it->incr_error = incr_error;
+	trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
+			   ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
+
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	if (ovalue) {
+		cputime_to_timeval(cval, &ovalue->it_value);
+		cputime_to_timeval(cinterval, &ovalue->it_interval);
+	}
+}
+
+/*
+ * Returns true if the timeval is in canonical form
+ */
+#define timeval_valid(t) \
+	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
+
+int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
+{
+	struct task_struct *tsk = current;
+	struct hrtimer *timer;
+	ktime_t expires;
+
+	/*
+	 * Validate the timevals in value.
+	 */
+	if (!timeval_valid(&value->it_value) ||
+	    !timeval_valid(&value->it_interval))
+		return -EINVAL;
+
+	switch (which) {
+	case ITIMER_REAL:
+again:
+		spin_lock_irq(&tsk->sighand->siglock);
+		timer = &tsk->signal->real_timer;
+		if (ovalue) {
+			ovalue->it_value = itimer_get_remtime(timer);
+			ovalue->it_interval
+				= ktime_to_timeval(tsk->signal->it_real_incr);
+		}
+		/* We are sharing ->siglock with it_real_fn() */
+		if (hrtimer_try_to_cancel(timer) < 0) {
+			spin_unlock_irq(&tsk->sighand->siglock);
+			goto again;
+		}
+		expires = timeval_to_ktime(value->it_value);
+		if (expires.tv64 != 0) {
+			tsk->signal->it_real_incr =
+				timeval_to_ktime(value->it_interval);
+			hrtimer_start(timer, expires, HRTIMER_MODE_REL);
+		} else
+			tsk->signal->it_real_incr.tv64 = 0;
+
+		trace_itimer_state(ITIMER_REAL, value, 0);
+		spin_unlock_irq(&tsk->sighand->siglock);
+		break;
+	case ITIMER_VIRTUAL:
+		set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
+		break;
+	case ITIMER_PROF:
+		set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds:	number of seconds until alarm
+ *		0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+unsigned int alarm_setitimer(unsigned int seconds)
+{
+	struct itimerval it_new, it_old;
+
+#if BITS_PER_LONG < 64
+	if (seconds > INT_MAX)
+		seconds = INT_MAX;
+#endif
+	it_new.it_value.tv_sec = seconds;
+	it_new.it_value.tv_usec = 0;
+	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
+
+	do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+	/*
+	 * We can't return 0 if we have an alarm pending ...  And we'd
+	 * better return too much than too little anyway
+	 */
+	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
+	      it_old.it_value.tv_usec >= 500000)
+		it_old.it_value.tv_sec++;
+
+	return it_old.it_value.tv_sec;
+}
+
+SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
+		struct itimerval __user *, ovalue)
+{
+	struct itimerval set_buffer, get_buffer;
+	int error;
+
+	if (value) {
+		if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
+			return -EFAULT;
+	} else {
+		memset(&set_buffer, 0, sizeof(set_buffer));
+		printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+			    " Misfeature support will be removed\n",
+			    current->comm);
+	}
+
+	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
+	if (error || !ovalue)
+		return error;
+
+	if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
+		return -EFAULT;
+	return 0;
+}

kernel/time/ntp.c

@@ -466,7 +466,8 @@ static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
 
 static void sync_cmos_clock(struct work_struct *work)
 {
-	struct timespec now, next;
+	struct timespec64 now;
+	struct timespec next;
 	int fail = 1;
 
 	/*
@@ -485,9 +486,9 @@ static void sync_cmos_clock(struct work_struct *work)
 		return;
 	}
 
-	getnstimeofday(&now);
+	getnstimeofday64(&now);
 	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec * 5) {
-		struct timespec adjust = now;
+		struct timespec adjust = timespec64_to_timespec(now);
 
 		fail = -ENODEV;
 		if (persistent_clock_is_local)
@@ -531,7 +532,7 @@ void ntp_notify_cmos_timer(void) { }
 /*
  * Propagate a new txc->status value into the NTP state:
  */
-static inline void process_adj_status(struct timex *txc, struct timespec *ts)
+static inline void process_adj_status(struct timex *txc, struct timespec64 *ts)
 {
 	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
 		time_state = TIME_OK;
@@ -554,7 +555,7 @@ static inline void process_adj_status(struct timex *txc, struct timespec *ts)
 
 
 static inline void process_adjtimex_modes(struct timex *txc,
-						struct timespec *ts,
+						struct timespec64 *ts,
 						s32 *time_tai)
 {
 	if (txc->modes & ADJ_STATUS)
@@ -640,7 +641,7 @@ int ntp_validate_timex(struct timex *txc)
  * adjtimex mainly allows reading (and writing, if superuser) of
  * kernel time-keeping variables. used by xntpd.
  */
-int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai)
+int __do_adjtimex(struct timex *txc, struct timespec64 *ts, s32 *time_tai)
 {
 	int result;
 
@@ -684,7 +685,7 @@ int __do_adjtimex(struct timex *txc, struct timespec *ts, s32 *time_tai)
 	/* fill PPS status fields */
 	pps_fill_timex(txc);
 
-	txc->time.tv_sec = ts->tv_sec;
+	txc->time.tv_sec = (time_t)ts->tv_sec;
 	txc->time.tv_usec = ts->tv_nsec;
 	if (!(time_status & STA_NANO))
 		txc->time.tv_usec /= NSEC_PER_USEC;

kernel/time/ntp_internal.h

@@ -7,6 +7,6 @@ extern void ntp_clear(void);
 extern u64 ntp_tick_length(void);
 extern int second_overflow(unsigned long secs);
 extern int ntp_validate_timex(struct timex *);
-extern int __do_adjtimex(struct timex *, struct timespec *, s32 *);
+extern int __do_adjtimex(struct timex *, struct timespec64 *, s32 *);
 extern void __hardpps(const struct timespec *, const struct timespec *);
 #endif /* _LINUX_NTP_INTERNAL_H */

kernel/time/tick-internal.h

@@ -4,6 +4,8 @@
 #include <linux/hrtimer.h>
 #include <linux/tick.h>
 
+#include "timekeeping.h"
+
 extern seqlock_t jiffies_lock;
 
 #define CS_NAME_LEN	32

kernel/time/timeconst.bc

@@ -0,0 +1,108 @@
+scale=0
+
+define gcd(a,b) {
+	auto t;
+	while (b) {
+		t = b;
+		b = a % b;
+		a = t;
+	}
+	return a;
+}
+
+/* Division by reciprocal multiplication. */
+define fmul(b,n,d) {
+       return (2^b*n+d-1)/d;
+}
+
+/* Adjustment factor when a ceiling value is used.  Use as:
+   (imul * n) + (fmulxx * n + fadjxx) >> xx) */
+define fadj(b,n,d) {
+	auto v;
+	d = d/gcd(n,d);
+	v = 2^b*(d-1)/d;
+	return v;
+}
+
+/* Compute the appropriate mul/adj values as well as a shift count,
+   which brings the mul value into the range 2^b-1 <= x < 2^b.  Such
+   a shift value will be correct in the signed integer range and off
+   by at most one in the upper half of the unsigned range. */
+define fmuls(b,n,d) {
+	auto s, m;
+	for (s = 0; 1; s++) {
+		m = fmul(s,n,d);
+		if (m >= 2^(b-1))
+			return s;
+	}
+	return 0;
+}
+
+define timeconst(hz) {
+	print "/* Automatically generated by kernel/timeconst.bc */\n"
+	print "/* Time conversion constants for HZ == ", hz, " */\n"
+	print "\n"
+
+	print "#ifndef KERNEL_TIMECONST_H\n"
+	print "#define KERNEL_TIMECONST_H\n\n"
+
+	print "#include <linux/param.h>\n"
+	print "#include <linux/types.h>\n\n"
+
+	print "#if HZ != ", hz, "\n"
+	print "#error \qkernel/timeconst.h has the wrong HZ value!\q\n"
+	print "#endif\n\n"
+
+	if (hz < 2) {
+		print "#error Totally bogus HZ value!\n"
+	} else {
+		s=fmuls(32,1000,hz)
+		obase=16
+		print "#define HZ_TO_MSEC_MUL32\tU64_C(0x", fmul(s,1000,hz), ")\n"
+		print "#define HZ_TO_MSEC_ADJ32\tU64_C(0x", fadj(s,1000,hz), ")\n"
+		obase=10
+		print "#define HZ_TO_MSEC_SHR32\t", s, "\n"
+
+		s=fmuls(32,hz,1000)
+		obase=16
+		print "#define MSEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000), ")\n"
+		print "#define MSEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000), ")\n"
+		obase=10
+		print "#define MSEC_TO_HZ_SHR32\t", s, "\n"
+
+		obase=10
+		cd=gcd(hz,1000)
+		print "#define HZ_TO_MSEC_NUM\t\t", 1000/cd, "\n"
+		print "#define HZ_TO_MSEC_DEN\t\t", hz/cd, "\n"
+		print "#define MSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+		print "#define MSEC_TO_HZ_DEN\t\t", 1000/cd, "\n"
+		print "\n"
+
+		s=fmuls(32,1000000,hz)
+		obase=16
+		print "#define HZ_TO_USEC_MUL32\tU64_C(0x", fmul(s,1000000,hz), ")\n"
+		print "#define HZ_TO_USEC_ADJ32\tU64_C(0x", fadj(s,1000000,hz), ")\n"
+		obase=10
+		print "#define HZ_TO_USEC_SHR32\t", s, "\n"
+
+		s=fmuls(32,hz,1000000)
+		obase=16
+		print "#define USEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000000), ")\n"
+		print "#define USEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000000), ")\n"
+		obase=10
+		print "#define USEC_TO_HZ_SHR32\t", s, "\n"
+
+		obase=10
+		cd=gcd(hz,1000000)
+		print "#define HZ_TO_USEC_NUM\t\t", 1000000/cd, "\n"
+		print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
+		print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+		print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
+		print "\n"
+
+		print "#endif /* KERNEL_TIMECONST_H */\n"
+	}
+	halt
+}
+
+timeconst(hz)

kernel/time/timekeeping.h

@@ -0,0 +1,20 @@
+#ifndef _KERNEL_TIME_TIMEKEEPING_H
+#define _KERNEL_TIME_TIMEKEEPING_H
+/*
+ * Internal interfaces for kernel/time/
+ */
+extern ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real,
+						ktime_t *offs_boot,
+						ktime_t *offs_tai);
+extern ktime_t ktime_get_update_offsets_now(ktime_t *offs_real,
+						ktime_t *offs_boot,
+						ktime_t *offs_tai);
+
+extern int timekeeping_valid_for_hres(void);
+extern u64 timekeeping_max_deferment(void);
+extern int timekeeping_inject_offset(struct timespec *ts);
+extern s32 timekeeping_get_tai_offset(void);
+extern void timekeeping_set_tai_offset(s32 tai_offset);
+extern void timekeeping_clocktai(struct timespec *ts);
+
+#endif

kernel/time/timekeeping_debug.c

@@ -67,7 +67,7 @@ static int __init tk_debug_sleep_time_init(void)
 }
 late_initcall(tk_debug_sleep_time_init);
 
-void tk_debug_account_sleep_time(struct timespec *t)
+void tk_debug_account_sleep_time(struct timespec64 *t)
 {
 	sleep_time_bin[fls(t->tv_sec)]++;
 }

kernel/time/timekeeping_internal.h

@@ -3,12 +3,27 @@
 /*
  * timekeeping debug functions
  */
+#include <linux/clocksource.h>
 #include <linux/time.h>
 
 #ifdef CONFIG_DEBUG_FS
-extern void tk_debug_account_sleep_time(struct timespec *t);
+extern void tk_debug_account_sleep_time(struct timespec64 *t);
 #else
 #define tk_debug_account_sleep_time(x)
 #endif
 
+#ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
+static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
+{
+	cycle_t ret = (now - last) & mask;
+
+	return (s64) ret > 0 ? ret : 0;
+}
+#else
+static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
+{
+	return (now - last) & mask;
+}
+#endif
+
 #endif /* _TIMEKEEPING_INTERNAL_H */

kernel/time/udelay_test.c

@@ -0,0 +1,168 @@
+/*
+ * udelay() test kernel module
+ *
+ * Test is executed by writing and reading to /sys/kernel/debug/udelay_test
+ * Tests are configured by writing: USECS ITERATIONS
+ * Tests are executed by reading from the same file.
+ * Specifying usecs of 0 or negative values will run multiples tests.
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#define DEFAULT_ITERATIONS 100
+
+#define DEBUGFS_FILENAME "udelay_test"
+
+static DEFINE_MUTEX(udelay_test_lock);
+static struct dentry *udelay_test_debugfs_file;
+static int udelay_test_usecs;
+static int udelay_test_iterations = DEFAULT_ITERATIONS;
+
+static int udelay_test_single(struct seq_file *s, int usecs, uint32_t iters)
+{
+	int min = 0, max = 0, fail_count = 0;
+	uint64_t sum = 0;
+	uint64_t avg;
+	int i;
+	/* Allow udelay to be up to 0.5% fast */
+	int allowed_error_ns = usecs * 5;
+
+	for (i = 0; i < iters; ++i) {
+		struct timespec ts1, ts2;
+		int time_passed;
+
+		ktime_get_ts(&ts1);
+		udelay(usecs);
+		ktime_get_ts(&ts2);
+		time_passed = timespec_to_ns(&ts2) - timespec_to_ns(&ts1);
+
+		if (i == 0 || time_passed < min)
+			min = time_passed;
+		if (i == 0 || time_passed > max)
+			max = time_passed;
+		if ((time_passed + allowed_error_ns) / 1000 < usecs)
+			++fail_count;
+		WARN_ON(time_passed < 0);
+		sum += time_passed;
+	}
+
+	avg = sum;
+	do_div(avg, iters);
+	seq_printf(s, "%d usecs x %d: exp=%d allowed=%d min=%d avg=%lld max=%d",
+			usecs, iters, usecs * 1000,
+			(usecs * 1000) - allowed_error_ns, min, avg, max);
+	if (fail_count)
+		seq_printf(s, " FAIL=%d", fail_count);
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+static int udelay_test_show(struct seq_file *s, void *v)
+{
+	int usecs;
+	int iters;
+	int ret = 0;
+
+	mutex_lock(&udelay_test_lock);
+	usecs = udelay_test_usecs;
+	iters = udelay_test_iterations;
+	mutex_unlock(&udelay_test_lock);
+
+	if (usecs > 0 && iters > 0) {
+		return udelay_test_single(s, usecs, iters);
+	} else if (usecs == 0) {
+		struct timespec ts;
+
+		ktime_get_ts(&ts);
+		seq_printf(s, "udelay() test (lpj=%ld kt=%ld.%09ld)\n",
+				loops_per_jiffy, ts.tv_sec, ts.tv_nsec);
+		seq_puts(s, "usage:\n");
+		seq_puts(s, "echo USECS [ITERS] > " DEBUGFS_FILENAME "\n");
+		seq_puts(s, "cat " DEBUGFS_FILENAME "\n");
+	}
+
+	return ret;
+}
+
+static int udelay_test_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, udelay_test_show, inode->i_private);
+}
+
+static ssize_t udelay_test_write(struct file *file, const char __user *buf,
+		size_t count, loff_t *pos)
+{
+	char lbuf[32];
+	int ret;
+	int usecs;
+	int iters;
+
+	if (count >= sizeof(lbuf))
+		return -EINVAL;
+
+	if (copy_from_user(lbuf, buf, count))
+		return -EFAULT;
+	lbuf[count] = '\0';
+
+	ret = sscanf(lbuf, "%d %d", &usecs, &iters);
+	if (ret < 1)
+		return -EINVAL;
+	else if (ret < 2)
+		iters = DEFAULT_ITERATIONS;
+
+	mutex_lock(&udelay_test_lock);
+	udelay_test_usecs = usecs;
+	udelay_test_iterations = iters;
+	mutex_unlock(&udelay_test_lock);
+
+	return count;
+}
+
+static const struct file_operations udelay_test_debugfs_ops = {
+	.owner = THIS_MODULE,
+	.open = udelay_test_open,
+	.read = seq_read,
+	.write = udelay_test_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int __init udelay_test_init(void)
+{
+	mutex_lock(&udelay_test_lock);
+	udelay_test_debugfs_file = debugfs_create_file(DEBUGFS_FILENAME,
+			S_IRUSR, NULL, NULL, &udelay_test_debugfs_ops);
+	mutex_unlock(&udelay_test_lock);
+
+	return 0;
+}
+
+module_init(udelay_test_init);
+
+static void __exit udelay_test_exit(void)
+{
+	mutex_lock(&udelay_test_lock);
+	debugfs_remove(udelay_test_debugfs_file);
+	mutex_unlock(&udelay_test_lock);
+}
+
+module_exit(udelay_test_exit);
+
+MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
+MODULE_LICENSE("GPL");