selftests/timers: Add leap-a-day test from timetest suite

This change adds the leap-a-day test which sets STA_INS and
STA_DEL each day to trigger leapseconds each day. It also
has a mode to jump the time to right before the end of the
day each iteration.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/timers/Makefile

@@ -5,6 +5,7 @@ LDFLAGS += -lrt -lpthread
 bins = posix_timers nanosleep inconsistency-check nsleep-lat raw_skew \
 	set-timer-lat threadtest mqueue-lat valid-adjtimex \
 	alarmtimer-suspend change_skew skew_consistency clocksource-switch \
+	leap-a-day
 
 all: ${bins}
 
@@ -29,6 +30,7 @@ run_destructive_tests: run_tests
 	./change_skew
 	./skew_consistency
 	./clocksource-switch
+	./leap-a-day -s -i 10
 
 clean:
 	rm -f ${bins}

tools/testing/selftests/timers/leap-a-day.c

+/* Leap second stress test
+ *              by: John Stultz (john.stultz@linaro.org)
+ *              (C) Copyright IBM 2012
+ *              (C) Copyright 2013, 2015 Linaro Limited
+ *              Licensed under the GPLv2
+ *
+ *  This test signals the kernel to insert a leap second
+ *  every day at midnight GMT. This allows for stessing the
+ *  kernel's leap-second behavior, as well as how well applications
+ *  handle the leap-second discontinuity.
+ *
+ *  Usage: leap-a-day [-s] [-i <num>]
+ *
+ *  Options:
+ *	-s:	Each iteration, set the date to 10 seconds before midnight GMT.
+ *		This speeds up the number of leapsecond transitions tested,
+ *		but because it calls settimeofday frequently, advancing the
+ *		time by 24 hours every ~16 seconds, it may cause application
+ *		disruption.
+ *
+ *	-i:	Number of iterations to run (default: infinite)
+ *
+ *  Other notes: Disabling NTP prior to running this is advised, as the two
+ *		 may conflict in their commands to the kernel.
+ *
+ *  To build:
+ *	$ gcc leap-a-day.c -o leap-a-day -lrt
+ *
+ *   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.
+ */
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+	exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+	exit(1);
+}
+#endif
+
+#define NSEC_PER_SEC 1000000000ULL
+#define CLOCK_TAI 11
+
+/* returns 1 if a <= b, 0 otherwise */
+static inline int in_order(struct timespec a, struct timespec b)
+{
+	if (a.tv_sec < b.tv_sec)
+		return 1;
+	if (a.tv_sec > b.tv_sec)
+		return 0;
+	if (a.tv_nsec > b.tv_nsec)
+		return 0;
+	return 1;
+}
+
+struct timespec timespec_add(struct timespec ts, unsigned long long ns)
+{
+	ts.tv_nsec += ns;
+	while (ts.tv_nsec >= NSEC_PER_SEC) {
+		ts.tv_nsec -= NSEC_PER_SEC;
+		ts.tv_sec++;
+	}
+	return ts;
+}
+
+char *time_state_str(int state)
+{
+	switch (state) {
+	case TIME_OK:	return "TIME_OK";
+	case TIME_INS:	return "TIME_INS";
+	case TIME_DEL:	return "TIME_DEL";
+	case TIME_OOP:	return "TIME_OOP";
+	case TIME_WAIT:	return "TIME_WAIT";
+	case TIME_BAD:	return "TIME_BAD";
+	}
+	return "ERROR";
+}
+
+/* clear NTP time_status & time_state */
+int clear_time_state(void)
+{
+	struct timex tx;
+	int ret;
+
+	/*
+	 * We have to call adjtime twice here, as kernels
+	 * prior to 6b1859dba01c7 (included in 3.5 and
+	 * -stable), had an issue with the state machine
+	 * and wouldn't clear the STA_INS/DEL flag directly.
+	 */
+	tx.modes = ADJ_STATUS;
+	tx.status = STA_PLL;
+	ret = adjtimex(&tx);
+
+	/* Clear maxerror, as it can cause UNSYNC to be set */
+	tx.modes = ADJ_MAXERROR;
+	tx.maxerror = 0;
+	ret = adjtimex(&tx);
+
+	/* Clear the status */
+	tx.modes = ADJ_STATUS;
+	tx.status = 0;
+	ret = adjtimex(&tx);
+
+	return ret;
+}
+
+/* Make sure we cleanup on ctrl-c */
+void handler(int unused)
+{
+	clear_time_state();
+	exit(0);
+}
+
+/* Test for known hrtimer failure */
+void test_hrtimer_failure(void)
+{
+	struct timespec now, target;
+
+	clock_gettime(CLOCK_REALTIME, &now);
+	target = timespec_add(now, NSEC_PER_SEC/2);
+	clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &target, NULL);
+	clock_gettime(CLOCK_REALTIME, &now);
+
+	if (!in_order(target, now))
+		printf("ERROR: hrtimer early expiration failure observed.\n");
+}
+
+int main(int argc, char **argv)
+{
+	int settime = 0;
+	int tai_time = 0;
+	int insert = 1;
+	int iterations = -1;
+	int opt;
+
+	/* Process arguments */
+	while ((opt = getopt(argc, argv, "sti:")) != -1) {
+		switch (opt) {
+		case 's':
+			printf("Setting time to speed up testing\n");
+			settime = 1;
+			break;
+		case 'i':
+			iterations = atoi(optarg);
+			break;
+		case 't':
+			tai_time = 1;
+			break;
+		default:
+			printf("Usage: %s [-s] [-i <iterations>]\n", argv[0]);
+			printf("	-s: Set time to right before leap second each iteration\n");
+			printf("	-i: Number of iterations\n");
+			printf("	-t: Print TAI time\n");
+			exit(-1);
+		}
+	}
+
+	/* Make sure TAI support is present if -t was used */
+	if (tai_time) {
+		struct timespec ts;
+
+		if (clock_gettime(CLOCK_TAI, &ts)) {
+			printf("System doesn't support CLOCK_TAI\n");
+			ksft_exit_fail();
+		}
+	}
+
+	signal(SIGINT, handler);
+	signal(SIGKILL, handler);
+
+	if (iterations < 0)
+		printf("This runs continuously. Press ctrl-c to stop\n");
+	else
+		printf("Running for %i iterations. Press ctrl-c to stop\n", iterations);
+
+	printf("\n");
+	while (1) {
+		int ret;
+		struct timespec ts;
+		struct timex tx;
+		time_t now, next_leap;
+
+		/* Get the current time */
+		clock_gettime(CLOCK_REALTIME, &ts);
+
+		/* Calculate the next possible leap second 23:59:60 GMT */
+		next_leap = ts.tv_sec;
+		next_leap += 86400 - (next_leap % 86400);
+
+		if (settime) {
+			struct timeval tv;
+
+			tv.tv_sec = next_leap - 10;
+			tv.tv_usec = 0;
+			settimeofday(&tv, NULL);
+			printf("Setting time to %s", ctime(&tv.tv_sec));
+		}
+
+		/* Reset NTP time state */
+		clear_time_state();
+
+		/* Set the leap second insert flag */
+		tx.modes = ADJ_STATUS;
+		if (insert)
+			tx.status = STA_INS;
+		else
+			tx.status = STA_DEL;
+		ret = adjtimex(&tx);
+		if (ret < 0) {
+			printf("Error: Problem setting STA_INS/STA_DEL!: %s\n",
+							time_state_str(ret));
+			return ksft_exit_fail();
+		}
+
+		/* Validate STA_INS was set */
+		tx.modes = 0;
+		ret = adjtimex(&tx);
+		if (tx.status != STA_INS && tx.status != STA_DEL) {
+			printf("Error: STA_INS/STA_DEL not set!: %s\n",
+							time_state_str(ret));
+			return ksft_exit_fail();
+		}
+
+		if (tai_time) {
+			printf("Using TAI time,"
+				" no inconsistencies should be seen!\n");
+		}
+
+		printf("Scheduling leap second for %s", ctime(&next_leap));
+
+		/* Wake up 3 seconds before leap */
+		ts.tv_sec = next_leap - 3;
+		ts.tv_nsec = 0;
+
+		while (clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL))
+			printf("Something woke us up, returning to sleep\n");
+
+		/* Validate STA_INS is still set */
+		tx.modes = 0;
+		ret = adjtimex(&tx);
+		if (tx.status != STA_INS && tx.status != STA_DEL) {
+			printf("Something cleared STA_INS/STA_DEL, setting it again.\n");
+			tx.modes = ADJ_STATUS;
+			if (insert)
+				tx.status = STA_INS;
+			else
+				tx.status = STA_DEL;
+			ret = adjtimex(&tx);
+		}
+
+		/* Check adjtimex output every half second */
+		now = tx.time.tv_sec;
+		while (now < next_leap + 2) {
+			char buf[26];
+			struct timespec tai;
+
+			tx.modes = 0;
+			ret = adjtimex(&tx);
+
+			if (tai_time) {
+				clock_gettime(CLOCK_TAI, &tai);
+				printf("%ld sec, %9ld ns\t%s\n",
+						tai.tv_sec,
+						tai.tv_nsec,
+						time_state_str(ret));
+			} else {
+				ctime_r(&tx.time.tv_sec, buf);
+				buf[strlen(buf)-1] = 0; /*remove trailing\n */
+
+				printf("%s + %6ld us (%i)\t%s\n",
+						buf,
+						tx.time.tv_usec,
+						tx.tai,
+						time_state_str(ret));
+			}
+			now = tx.time.tv_sec;
+			/* Sleep for another half second */
+			ts.tv_sec = 0;
+			ts.tv_nsec = NSEC_PER_SEC / 2;
+			clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL);
+		}
+		/* Switch to using other mode */
+		insert = !insert;
+
+		/* Note if kernel has known hrtimer failure */
+		test_hrtimer_failure();
+
+		printf("Leap complete\n\n");
+
+		if ((iterations != -1) && !(--iterations))
+			break;
+	}
+
+	clear_time_state();
+	return ksft_exit_pass();
+}