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

Pull timer updates from Thomas Gleixner:
 "The timer departement provides:

   - More y2038 work in the area of ntp and pps.

   - Optimization of posix cpu timers

   - New time related selftests

   - Some new clocksource drivers

   - The usual pile of fixes, cleanups and improvements"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  timeconst: Update path in comment
  timers/x86/hpet: Type adjustments
  clocksource/drivers/armada-370-xp: Implement ARM delay timer
  clocksource/drivers/tango_xtal: Add new timer for Tango SoCs
  clocksource/drivers/imx: Allow timer irq affinity change
  clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()
  clocksource/drivers/h8300_*: Remove unneeded memset()s
  clocksource/drivers/sh_cmt: Remove unneeded memset() in sh_cmt_setup()
  clocksource/drivers/em_sti: Remove unneeded memset()s
  clocksource/drivers/mediatek: Use GPT as sched clock source
  clockevents/drivers/mtk: Fix spurious interrupt leading to crash
  posix_cpu_timer: Reduce unnecessary sighand lock contention
  posix_cpu_timer: Convert cputimer->running to bool
  posix_cpu_timer: Check thread timers only when there are active thread timers
  posix_cpu_timer: Optimize fastpath_timer_check()
  timers, kselftest: Add 'adjtick' test to validate adjtimex() tick adjustments
  timers: Use __fls in apply_slack()
  clocksource: Remove return statement from void functions
  net: sfc: avoid using timespec
  ntp/pps: use y2038 safe types in pps_event_time
  ...

arch/x86/include/asm/hpet.h

@@ -63,10 +63,10 @@
 /* hpet memory map physical address */
 extern unsigned long hpet_address;
 extern unsigned long force_hpet_address;
-extern int boot_hpet_disable;
+extern bool boot_hpet_disable;
 extern u8 hpet_blockid;
-extern int hpet_force_user;
-extern u8 hpet_msi_disable;
+extern bool hpet_force_user;
+extern bool hpet_msi_disable;
 extern int is_hpet_enabled(void);
 extern int hpet_enable(void);
 extern void hpet_disable(void);

arch/x86/kernel/early-quirks.c

@@ -584,7 +584,7 @@ static void __init intel_graphics_stolen(int num, int slot, int func)
 static void __init force_disable_hpet(int num, int slot, int func)
 {
 #ifdef CONFIG_HPET_TIMER
-	boot_hpet_disable = 1;
+	boot_hpet_disable = true;
 	pr_info("x86/hpet: Will disable the HPET for this platform because it's not reliable\n");
 #endif
 }

arch/x86/kernel/hpet.c

@@ -37,10 +37,10 @@
  */
 unsigned long				hpet_address;
 u8					hpet_blockid; /* OS timer block num */
-u8					hpet_msi_disable;
+bool					hpet_msi_disable;
 
 #ifdef CONFIG_PCI_MSI
-static unsigned long			hpet_num_timers;
+static unsigned int			hpet_num_timers;
 #endif
 static void __iomem			*hpet_virt_address;
 
@@ -86,9 +86,9 @@ static inline void hpet_clear_mapping(void)
 /*
  * HPET command line enable / disable
  */
-int boot_hpet_disable;
-int hpet_force_user;
-static int hpet_verbose;
+bool boot_hpet_disable;
+bool hpet_force_user;
+static bool hpet_verbose;
 
 static int __init hpet_setup(char *str)
 {
@@ -98,11 +98,11 @@ static int __init hpet_setup(char *str)
 		if (next)
 			*next++ = 0;
 		if (!strncmp("disable", str, 7))
-			boot_hpet_disable = 1;
+			boot_hpet_disable = true;
 		if (!strncmp("force", str, 5))
-			hpet_force_user = 1;
+			hpet_force_user = true;
 		if (!strncmp("verbose", str, 7))
-			hpet_verbose = 1;
+			hpet_verbose = true;
 		str = next;
 	}
 	return 1;
@@ -111,7 +111,7 @@ __setup("hpet=", hpet_setup);
 
 static int __init disable_hpet(char *str)
 {
-	boot_hpet_disable = 1;
+	boot_hpet_disable = true;
 	return 1;
 }
 __setup("nohpet", disable_hpet);
@@ -124,7 +124,7 @@ static inline int is_hpet_capable(void)
 /*
  * HPET timer interrupt enable / disable
  */
-static int hpet_legacy_int_enabled;
+static bool hpet_legacy_int_enabled;
 
 /**
  * is_hpet_enabled - check whether the hpet timer interrupt is enabled
@@ -230,7 +230,7 @@ static struct clock_event_device hpet_clockevent;
 
 static void hpet_stop_counter(void)
 {
-	unsigned long cfg = hpet_readl(HPET_CFG);
+	u32 cfg = hpet_readl(HPET_CFG);
 	cfg &= ~HPET_CFG_ENABLE;
 	hpet_writel(cfg, HPET_CFG);
 }
@@ -272,7 +272,7 @@ static void hpet_enable_legacy_int(void)
 
 	cfg |= HPET_CFG_LEGACY;
 	hpet_writel(cfg, HPET_CFG);
-	hpet_legacy_int_enabled = 1;
+	hpet_legacy_int_enabled = true;
 }
 
 static void hpet_legacy_clockevent_register(void)
@@ -983,7 +983,7 @@ void hpet_disable(void)
 			cfg = *hpet_boot_cfg;
 		else if (hpet_legacy_int_enabled) {
 			cfg &= ~HPET_CFG_LEGACY;
-			hpet_legacy_int_enabled = 0;
+			hpet_legacy_int_enabled = false;
 		}
 		cfg &= ~HPET_CFG_ENABLE;
 		hpet_writel(cfg, HPET_CFG);
@@ -1121,8 +1121,7 @@ EXPORT_SYMBOL_GPL(hpet_rtc_timer_init);
 
 static void hpet_disable_rtc_channel(void)
 {
-	unsigned long cfg;
-	cfg = hpet_readl(HPET_T1_CFG);
+	u32 cfg = hpet_readl(HPET_T1_CFG);
 	cfg &= ~HPET_TN_ENABLE;
 	hpet_writel(cfg, HPET_T1_CFG);
 }

arch/x86/kernel/quirks.c

@@ -524,7 +524,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E6XX_CU,
  */
 static void force_disable_hpet_msi(struct pci_dev *unused)
 {
-	hpet_msi_disable = 1;
+	hpet_msi_disable = true;
 }
 
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS,

drivers/clocksource/Kconfig

@@ -279,6 +279,10 @@ config CLKSRC_MIPS_GIC
 	depends on MIPS_GIC
 	select CLKSRC_OF
 
+config CLKSRC_TANGO_XTAL
+	bool
+	select CLKSRC_OF
+
 config CLKSRC_PXA
 	def_bool y if ARCH_PXA || ARCH_SA1100
 	select CLKSRC_OF if OF

drivers/clocksource/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_ARCH_KEYSTONE)		+= timer-keystone.o
 obj-$(CONFIG_ARCH_INTEGRATOR_AP)	+= timer-integrator-ap.o
 obj-$(CONFIG_CLKSRC_VERSATILE)		+= versatile.o
 obj-$(CONFIG_CLKSRC_MIPS_GIC)		+= mips-gic-timer.o
+obj-$(CONFIG_CLKSRC_TANGO_XTAL)		+= tango_xtal.o
 obj-$(CONFIG_CLKSRC_IMX_GPT)		+= timer-imx-gpt.o
 obj-$(CONFIG_ASM9260_TIMER)		+= asm9260_timer.o
 obj-$(CONFIG_H8300)			+= h8300_timer8.o

drivers/clocksource/em_sti.c

@@ -228,7 +228,6 @@ static int em_sti_register_clocksource(struct em_sti_priv *p)
 {
 	struct clocksource *cs = &p->cs;
 
-	memset(cs, 0, sizeof(*cs));
 	cs->name = dev_name(&p->pdev->dev);
 	cs->rating = 200;
 	cs->read = em_sti_clocksource_read;
@@ -285,7 +284,6 @@ static void em_sti_register_clockevent(struct em_sti_priv *p)
 {
 	struct clock_event_device *ced = &p->ced;
 
-	memset(ced, 0, sizeof(*ced));
 	ced->name = dev_name(&p->pdev->dev);
 	ced->features = CLOCK_EVT_FEAT_ONESHOT;
 	ced->rating = 200;

drivers/clocksource/exynos_mct.c

@@ -382,24 +382,28 @@ static void exynos4_mct_tick_start(unsigned long cycles,
 static int exynos4_tick_set_next_event(unsigned long cycles,
 				       struct clock_event_device *evt)
 {
-	struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+	struct mct_clock_event_device *mevt;
 
+	mevt = container_of(evt, struct mct_clock_event_device, evt);
 	exynos4_mct_tick_start(cycles, mevt);
-
 	return 0;
 }
 
 static int set_state_shutdown(struct clock_event_device *evt)
 {
-	exynos4_mct_tick_stop(this_cpu_ptr(&percpu_mct_tick));
+	struct mct_clock_event_device *mevt;
+
+	mevt = container_of(evt, struct mct_clock_event_device, evt);
+	exynos4_mct_tick_stop(mevt);
 	return 0;
 }
 
 static int set_state_periodic(struct clock_event_device *evt)
 {
-	struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+	struct mct_clock_event_device *mevt;
 	unsigned long cycles_per_jiffy;
 
+	mevt = container_of(evt, struct mct_clock_event_device, evt);
 	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
 			    >> evt->shift);
 	exynos4_mct_tick_stop(mevt);

drivers/clocksource/h8300_timer16.c

@@ -153,7 +153,6 @@ static int timer16_setup(struct timer16_priv *p, struct platform_device *pdev)
 	int ret, irq;
 	unsigned int ch;
 
-	memset(p, 0, sizeof(*p));
 	p->pdev = pdev;
 
 	res[REG_CH] = platform_get_resource(p->pdev,

drivers/clocksource/h8300_timer8.c

@@ -215,7 +215,6 @@ static int timer8_setup(struct timer8_priv *p,
 	int irq;
 	int ret;
 
-	memset(p, 0, sizeof(*p));
 	p->pdev = pdev;
 
 	res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);

drivers/clocksource/h8300_tpu.c

@@ -123,7 +123,6 @@ static int __init tpu_setup(struct tpu_priv *p, struct platform_device *pdev)
 {
 	struct resource *res[2];
 
-	memset(p, 0, sizeof(*p));
 	p->pdev = pdev;
 
 	res[CH_L] = platform_get_resource(p->pdev, IORESOURCE_MEM, CH_L);

drivers/clocksource/mtk_timer.c

@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/sched_clock.h>
 #include <linux/slab.h>
 
 #define GPT_IRQ_EN_REG		0x00
@@ -59,6 +60,13 @@ struct mtk_clock_event_device {
 	struct clock_event_device dev;
 };
 
+static void __iomem *gpt_sched_reg __read_mostly;
+
+static u64 notrace mtk_read_sched_clock(void)
+{
+	return readl_relaxed(gpt_sched_reg);
+}
+
 static inline struct mtk_clock_event_device *to_mtk_clk(
 				struct clock_event_device *c)
 {
@@ -141,14 +149,6 @@ static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
-{
-	/* Disable all interrupts */
-	writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
-	/* Acknowledge all interrupts */
-	writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
-}
-
 static void
 mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
 {
@@ -168,6 +168,12 @@ static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
 {
 	u32 val;
 
+	/* Disable all interrupts */
+	writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
+
+	/* Acknowledge all spurious pending interrupts */
+	writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
+
 	val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
 	writel(val | GPT_IRQ_ENABLE(timer),
 			evt->gpt_base + GPT_IRQ_EN_REG);
@@ -220,8 +226,6 @@ static void __init mtk_timer_init(struct device_node *node)
 	}
 	rate = clk_get_rate(clk);
 
-	mtk_timer_global_reset(evt);
-
 	if (request_irq(evt->dev.irq, mtk_timer_interrupt,
 			IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
 		pr_warn("failed to setup irq %d\n", evt->dev.irq);
@@ -234,6 +238,8 @@ static void __init mtk_timer_init(struct device_node *node)
 	mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
 	clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
 			node->name, rate, 300, 32, clocksource_mmio_readl_up);
+	gpt_sched_reg = evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC);
+	sched_clock_register(mtk_read_sched_clock, 32, rate);
 
 	/* Configure clock event */
 	mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);

drivers/clocksource/sh_cmt.c

@@ -962,7 +962,6 @@ static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
 	unsigned int i;
 	int ret;
 
-	memset(cmt, 0, sizeof(*cmt));
 	cmt->pdev = pdev;
 	raw_spin_lock_init(&cmt->lock);
 

drivers/clocksource/tango_xtal.c

@@ -0,0 +1,66 @@
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/of_address.h>
+#include <linux/printk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+
+static void __iomem *xtal_in_cnt;
+static struct delay_timer delay_timer;
+
+static unsigned long notrace read_xtal_counter(void)
+{
+	return readl_relaxed(xtal_in_cnt);
+}
+
+static u64 notrace read_sched_clock(void)
+{
+	return read_xtal_counter();
+}
+
+static cycle_t read_clocksource(struct clocksource *cs)
+{
+	return read_xtal_counter();
+}
+
+static struct clocksource tango_xtal = {
+	.name	= "tango-xtal",
+	.rating	= 350,
+	.read	= read_clocksource,
+	.mask	= CLOCKSOURCE_MASK(32),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init tango_clocksource_init(struct device_node *np)
+{
+	struct clk *clk;
+	int xtal_freq, ret;
+
+	xtal_in_cnt = of_iomap(np, 0);
+	if (xtal_in_cnt == NULL) {
+		pr_err("%s: invalid address\n", np->full_name);
+		return;
+	}
+
+	clk = of_clk_get(np, 0);
+	if (IS_ERR(clk)) {
+		pr_err("%s: invalid clock\n", np->full_name);
+		return;
+	}
+
+	xtal_freq = clk_get_rate(clk);
+	delay_timer.freq = xtal_freq;
+	delay_timer.read_current_timer = read_xtal_counter;
+
+	ret = clocksource_register_hz(&tango_xtal, xtal_freq);
+	if (ret != 0) {
+		pr_err("%s: registration failed\n", np->full_name);
+		return;
+	}
+
+	sched_clock_register(read_sched_clock, 32, xtal_freq);
+	register_current_timer_delay(&delay_timer);
+}
+
+CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);

drivers/clocksource/time-armada-370-xp.c

@@ -45,6 +45,8 @@
 #include <linux/percpu.h>
 #include <linux/syscore_ops.h>
 
+#include <asm/delay.h>
+
 /*
  * Timer block registers.
  */
@@ -249,6 +251,15 @@ struct syscore_ops armada_370_xp_timer_syscore_ops = {
 	.resume		= armada_370_xp_timer_resume,
 };
 
+static unsigned long armada_370_delay_timer_read(void)
+{
+	return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer armada_370_delay_timer = {
+	.read_current_timer = armada_370_delay_timer_read,
+};
+
 static void __init armada_370_xp_timer_common_init(struct device_node *np)
 {
 	u32 clr = 0, set = 0;
@@ -287,6 +298,9 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 		TIMER0_RELOAD_EN | enable_mask,
 		TIMER0_RELOAD_EN | enable_mask);
 
+	armada_370_delay_timer.freq = timer_clk;
+	register_current_timer_delay(&armada_370_delay_timer);
+
 	/*
 	 * Set scale and timer for sched_clock.
 	 */

drivers/clocksource/timer-imx-gpt.c

@@ -305,13 +305,14 @@ static int __init mxc_clockevent_init(struct imx_timer *imxtm)
 	struct irqaction *act = &imxtm->act;
 
 	ced->name = "mxc_timer1";
-	ced->features = CLOCK_EVT_FEAT_ONESHOT;
+	ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ;
 	ced->set_state_shutdown = mxc_shutdown;
 	ced->set_state_oneshot = mxc_set_oneshot;
 	ced->tick_resume = mxc_shutdown;
 	ced->set_next_event = imxtm->gpt->set_next_event;
 	ced->rating = 200;
 	ced->cpumask = cpumask_of(0);
+	ced->irq = imxtm->irq;
 	clockevents_config_and_register(ced, clk_get_rate(imxtm->clk_per),
 					0xff, 0xfffffffe);
 

drivers/net/ethernet/sfc/ptp.c

@@ -401,8 +401,8 @@ size_t efx_ptp_update_stats(struct efx_nic *efx, u64 *stats)
 /* For Siena platforms NIC time is s and ns */
 static void efx_ptp_ns_to_s_ns(s64 ns, u32 *nic_major, u32 *nic_minor)
 {
-	struct timespec ts = ns_to_timespec(ns);
-	*nic_major = ts.tv_sec;
+	struct timespec64 ts = ns_to_timespec64(ns);
+	*nic_major = (u32)ts.tv_sec;
 	*nic_minor = ts.tv_nsec;
 }
 
@@ -431,8 +431,8 @@ static ktime_t efx_ptp_s_ns_to_ktime_correction(u32 nic_major, u32 nic_minor,
  */
 static void efx_ptp_ns_to_s27(s64 ns, u32 *nic_major, u32 *nic_minor)
 {
-	struct timespec ts = ns_to_timespec(ns);
-	u32 maj = ts.tv_sec;
+	struct timespec64 ts = ns_to_timespec64(ns);
+	u32 maj = (u32)ts.tv_sec;
 	u32 min = (u32)(((u64)ts.tv_nsec * NS_TO_S27_MULT +
 			 (1ULL << (NS_TO_S27_SHIFT - 1))) >> NS_TO_S27_SHIFT);
 
@@ -646,28 +646,28 @@ static void efx_ptp_send_times(struct efx_nic *efx,
 			       struct pps_event_time *last_time)
 {
 	struct pps_event_time now;
-	struct timespec limit;
+	struct timespec64 limit;
 	struct efx_ptp_data *ptp = efx->ptp_data;
-	struct timespec start;
+	struct timespec64 start;
 	int *mc_running = ptp->start.addr;
 
 	pps_get_ts(&now);
 	start = now.ts_real;
 	limit = now.ts_real;
-	timespec_add_ns(&limit, SYNCHRONISE_PERIOD_NS);
+	timespec64_add_ns(&limit, SYNCHRONISE_PERIOD_NS);
 
 	/* Write host time for specified period or until MC is done */
-	while ((timespec_compare(&now.ts_real, &limit) < 0) &&
+	while ((timespec64_compare(&now.ts_real, &limit) < 0) &&
 	       ACCESS_ONCE(*mc_running)) {
-		struct timespec update_time;
+		struct timespec64 update_time;
 		unsigned int host_time;
 
 		/* Don't update continuously to avoid saturating the PCIe bus */
 		update_time = now.ts_real;
-		timespec_add_ns(&update_time, SYNCHRONISATION_GRANULARITY_NS);
+		timespec64_add_ns(&update_time, SYNCHRONISATION_GRANULARITY_NS);
 		do {
 			pps_get_ts(&now);
-		} while ((timespec_compare(&now.ts_real, &update_time) < 0) &&
+		} while ((timespec64_compare(&now.ts_real, &update_time) < 0) &&
 			 ACCESS_ONCE(*mc_running));
 
 		/* Synchronise NIC with single word of time only */
@@ -723,7 +723,7 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
 	struct efx_ptp_data *ptp = efx->ptp_data;
 	u32 last_sec;
 	u32 start_sec;
-	struct timespec delta;
+	struct timespec64 delta;
 	ktime_t mc_time;
 
 	if (number_readings == 0)
@@ -737,14 +737,14 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
 	 */
 	for (i = 0; i < number_readings; i++) {
 		s32 window, corrected;
-		struct timespec wait;
+		struct timespec64 wait;
 
 		efx_ptp_read_timeset(
 			MCDI_ARRAY_STRUCT_PTR(synch_buf,
 					      PTP_OUT_SYNCHRONIZE_TIMESET, i),
 			&ptp->timeset[i]);
 
-		wait = ktime_to_timespec(
+		wait = ktime_to_timespec64(
 			ptp->nic_to_kernel_time(0, ptp->timeset[i].wait, 0));
 		window = ptp->timeset[i].window;
 		corrected = window - wait.tv_nsec;
@@ -803,7 +803,7 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
 					  ptp->timeset[last_good].minor, 0);
 
 	/* Calculate delay from NIC top of second to last_time */
-	delta.tv_nsec += ktime_to_timespec(mc_time).tv_nsec;
+	delta.tv_nsec += ktime_to_timespec64(mc_time).tv_nsec;
 
 	/* Set PPS timestamp to match NIC top of second */
 	ptp->host_time_pps = *last_time;

drivers/pps/kapi.c

@@ -179,8 +179,8 @@ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
 	/* check event type */
 	BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0);
 
-	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
-			ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
+	dev_dbg(pps->dev, "PPS event at %lld.%09ld\n",
+			(s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
 
 	timespec_to_pps_ktime(&ts_real, ts->ts_real);
 

include/linux/init_task.h

@@ -59,7 +59,8 @@ extern struct fs_struct init_fs;
 	.rlim		= INIT_RLIMITS,					\
 	.cputimer	= { 						\
 		.cputime_atomic	= INIT_CPUTIME_ATOMIC,			\
-		.running	= 0,					\
+		.running	= false,				\
+		.checking_timer = false,				\
 	},								\
 	INIT_PREV_CPUTIME(sig)						\
 	.cred_guard_mutex =						\

include/linux/pps_kernel.h

@@ -48,9 +48,9 @@ struct pps_source_info {
 
 struct pps_event_time {
 #ifdef CONFIG_NTP_PPS
-	struct timespec ts_raw;
+	struct timespec64 ts_raw;
 #endif /* CONFIG_NTP_PPS */
-	struct timespec ts_real;
+	struct timespec64 ts_real;
 };
 
 /* The main struct */
@@ -105,7 +105,7 @@ extern void pps_event(struct pps_device *pps,
 struct pps_device *pps_lookup_dev(void const *cookie);
 
 static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
-		struct timespec ts)
+		struct timespec64 ts)
 {
 	kt->sec = ts.tv_sec;
 	kt->nsec = ts.tv_nsec;
@@ -115,24 +115,24 @@ static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
 
 static inline void pps_get_ts(struct pps_event_time *ts)
 {
-	getnstime_raw_and_real(&ts->ts_raw, &ts->ts_real);
+	ktime_get_raw_and_real_ts64(&ts->ts_raw, &ts->ts_real);
 }
 
 #else /* CONFIG_NTP_PPS */
 
 static inline void pps_get_ts(struct pps_event_time *ts)
 {
-	getnstimeofday(&ts->ts_real);
+	ktime_get_real_ts64(&ts->ts_real);
 }
 
 #endif /* CONFIG_NTP_PPS */
 
 /* Subtract known time delay from PPS event time(s) */
-static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec delta)
+static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
 {
-	ts->ts_real = timespec_sub(ts->ts_real, delta);
+	ts->ts_real = timespec64_sub(ts->ts_real, delta);
 #ifdef CONFIG_NTP_PPS
-	ts->ts_raw = timespec_sub(ts->ts_raw, delta);
+	ts->ts_raw = timespec64_sub(ts->ts_raw, delta);
 #endif
 }
 

include/linux/sched.h

@@ -617,15 +617,18 @@ struct task_cputime_atomic {
 /**
  * struct thread_group_cputimer - thread group interval timer counts
  * @cputime_atomic:	atomic thread group interval timers.
- * @running:		non-zero when there are timers running and
- * 			@cputime receives updates.
+ * @running:		true when there are timers running and
+ *			@cputime_atomic receives updates.
+ * @checking_timer:	true when a thread in the group is in the
+ *			process of checking for thread group timers.
  *
  * This structure contains the version of task_cputime, above, that is
  * used for thread group CPU timer calculations.
  */
 struct thread_group_cputimer {
 	struct task_cputime_atomic cputime_atomic;
-	int running;
+	bool running;
+	bool checking_timer;
 };
 
 #include <linux/rwsem.h>

include/linux/timekeeping.h

@@ -263,8 +263,8 @@ extern void timekeeping_inject_sleeptime64(struct timespec64 *delta);
 /*
  * PPS accessor
  */
-extern void getnstime_raw_and_real(struct timespec *ts_raw,
-				   struct timespec *ts_real);
+extern void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw,
+				        struct timespec64 *ts_real);
 
 /*
  * Persistent clock related interfaces

include/linux/timex.h

@@ -152,7 +152,7 @@ extern unsigned long tick_nsec;		/* SHIFTED_HZ period (nsec) */
 #define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
 
 extern int do_adjtimex(struct timex *);
-extern void hardpps(const struct timespec *, const struct timespec *);
+extern void hardpps(const struct timespec64 *, const struct timespec64 *);
 
 int read_current_timer(unsigned long *timer_val);
 void ntp_notify_cmos_timer(void);

kernel/fork.c

@@ -1101,7 +1101,7 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
 	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
 	if (cpu_limit != RLIM_INFINITY) {
 		sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
-		sig->cputimer.running = 1;
+		sig->cputimer.running = true;
 	}
 
 	/* The timer lists. */

kernel/time/clocksource.c

@@ -479,7 +479,7 @@ static u32 clocksource_max_adjustment(struct clocksource *cs)
  * return half the number of nanoseconds the hardware counter can technically
  * cover. This is done so that we can potentially detect problems caused by
  * delayed timers or bad hardware, which might result in time intervals that
- * are larger then what the math used can handle without overflows.
+ * are larger than what the math used can handle without overflows.
  */
 u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cyc)
 {
@@ -595,16 +595,15 @@ static void __clocksource_select(bool skipcur)
  */
 static void clocksource_select(void)
 {
-	return __clocksource_select(false);
+	__clocksource_select(false);
 }
 
 static void clocksource_select_fallback(void)
 {
-	return __clocksource_select(true);
+	__clocksource_select(true);
 }
 
 #else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */
-
 static inline void clocksource_select(void) { }
 static inline void clocksource_select_fallback(void) { }
 

kernel/time/hrtimer.c

@@ -59,7 +59,7 @@
 /*
  * The timer bases:
  *
- * There are more clockids then hrtimer bases. Thus, we index
+ * There are more clockids than hrtimer bases. Thus, we index
  * into the timer bases by the hrtimer_base_type enum. When trying
  * to reach a base using a clockid, hrtimer_clockid_to_base()
  * is used to convert from clockid to the proper hrtimer_base_type.

kernel/time/ntp.c

@@ -99,7 +99,7 @@ static time64_t			ntp_next_leap_sec = TIME64_MAX;
 static int pps_valid;		/* signal watchdog counter */
 static long pps_tf[3];		/* phase median filter */
 static long pps_jitter;		/* current jitter (ns) */
-static struct timespec pps_fbase; /* beginning of the last freq interval */
+static struct timespec64 pps_fbase; /* beginning of the last freq interval */
 static int pps_shift;		/* current interval duration (s) (shift) */
 static int pps_intcnt;		/* interval counter */
 static s64 pps_freq;		/* frequency offset (scaled ns/s) */
@@ -509,7 +509,7 @@ static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
 static void sync_cmos_clock(struct work_struct *work)
 {
 	struct timespec64 now;
-	struct timespec next;
+	struct timespec64 next;
 	int fail = 1;
 
 	/*
@@ -559,7 +559,7 @@ static void sync_cmos_clock(struct work_struct *work)
 		next.tv_nsec -= NSEC_PER_SEC;
 	}
 	queue_delayed_work(system_power_efficient_wq,
-			   &sync_cmos_work, timespec_to_jiffies(&next));
+			   &sync_cmos_work, timespec64_to_jiffies(&next));
 }
 
 void ntp_notify_cmos_timer(void)
@@ -773,13 +773,13 @@ int __do_adjtimex(struct timex *txc, struct timespec64 *ts, s32 *time_tai)
  * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
  * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */
 struct pps_normtime {
-	__kernel_time_t	sec;	/* seconds */
+	s64		sec;	/* seconds */
 	long		nsec;	/* nanoseconds */
 };
 
 /* normalize the timestamp so that nsec is in the
    ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
-static inline struct pps_normtime pps_normalize_ts(struct timespec ts)
+static inline struct pps_normtime pps_normalize_ts(struct timespec64 ts)
 {
 	struct pps_normtime norm = {
 		.sec = ts.tv_sec,
@@ -861,7 +861,7 @@ static long hardpps_update_freq(struct pps_normtime freq_norm)
 		pps_errcnt++;
 		pps_dec_freq_interval();
 		printk_deferred(KERN_ERR
-			"hardpps: PPSERROR: interval too long - %ld s\n",
+			"hardpps: PPSERROR: interval too long - %lld s\n",
 			freq_norm.sec);
 		return 0;
 	}
@@ -948,7 +948,7 @@ static void hardpps_update_phase(long error)
  * This code is based on David Mills's reference nanokernel
  * implementation. It was mostly rewritten but keeps the same idea.
  */
-void __hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
+void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
 {
 	struct pps_normtime pts_norm, freq_norm;
 
@@ -969,7 +969,7 @@ void __hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
 	}
 
 	/* ok, now we have a base for frequency calculation */
-	freq_norm = pps_normalize_ts(timespec_sub(*raw_ts, pps_fbase));
+	freq_norm = pps_normalize_ts(timespec64_sub(*raw_ts, pps_fbase));
 
 	/* check that the signal is in the range
 	 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */

kernel/time/ntp_internal.h

@@ -9,5 +9,5 @@ extern ktime_t ntp_get_next_leap(void);
 extern int second_overflow(unsigned long secs);
 extern int ntp_validate_timex(struct timex *);
 extern int __do_adjtimex(struct timex *, struct timespec64 *, s32 *);
-extern void __hardpps(const struct timespec *, const struct timespec *);
+extern void __hardpps(const struct timespec64 *, const struct timespec64 *);
 #endif /* _LINUX_NTP_INTERNAL_H */

kernel/time/posix-cpu-timers.c

@@ -249,7 +249,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 		 * but barriers are not required because update_gt_cputime()
 		 * can handle concurrent updates.
 		 */
-		WRITE_ONCE(cputimer->running, 1);
+		WRITE_ONCE(cputimer->running, true);
 	}
 	sample_cputime_atomic(times, &cputimer->cputime_atomic);
 }
@@ -864,6 +864,13 @@ static void check_thread_timers(struct task_struct *tsk,
 	unsigned long long expires;
 	unsigned long soft;
 
+	/*
+	 * If cputime_expires is zero, then there are no active
+	 * per thread CPU timers.
+	 */
+	if (task_cputime_zero(&tsk->cputime_expires))
+		return;
+
 	expires = check_timers_list(timers, firing, prof_ticks(tsk));
 	tsk_expires->prof_exp = expires_to_cputime(expires);
 
@@ -911,7 +918,7 @@ static inline void stop_process_timers(struct signal_struct *sig)
 	struct thread_group_cputimer *cputimer = &sig->cputimer;
 
 	/* Turn off cputimer->running. This is done without locking. */
-	WRITE_ONCE(cputimer->running, 0);
+	WRITE_ONCE(cputimer->running, false);
 }
 
 static u32 onecputick;
@@ -961,6 +968,19 @@ static void check_process_timers(struct task_struct *tsk,
 	struct task_cputime cputime;
 	unsigned long soft;
 
+	/*
+	 * If cputimer is not running, then there are no active
+	 * process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
+	 */
+	if (!READ_ONCE(tsk->signal->cputimer.running))
+		return;
+
+        /*
+	 * Signify that a thread is checking for process timers.
+	 * Write access to this field is protected by the sighand lock.
+	 */
+	sig->cputimer.checking_timer = true;
+
 	/*
 	 * Collect the current process totals.
 	 */
@@ -1015,6 +1035,8 @@ static void check_process_timers(struct task_struct *tsk,
 	sig->cputime_expires.sched_exp = sched_expires;
 	if (task_cputime_zero(&sig->cputime_expires))
 		stop_process_timers(sig);
+
+	sig->cputimer.checking_timer = false;
 }
 
 /*
@@ -1117,24 +1139,33 @@ static inline int task_cputime_expired(const struct task_cputime *sample,
 static inline int fastpath_timer_check(struct task_struct *tsk)
 {
 	struct signal_struct *sig;
-	cputime_t utime, stime;
-
-	task_cputime(tsk, &utime, &stime);
 
 	if (!task_cputime_zero(&tsk->cputime_expires)) {
-		struct task_cputime task_sample = {
-			.utime = utime,
-			.stime = stime,
-			.sum_exec_runtime = tsk->se.sum_exec_runtime
-		};
+		struct task_cputime task_sample;
 
+		task_cputime(tsk, &task_sample.utime, &task_sample.stime);
+		task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
 		if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
 			return 1;
 	}
 
 	sig = tsk->signal;
-	/* Check if cputimer is running. This is accessed without locking. */
-	if (READ_ONCE(sig->cputimer.running)) {
+	/*
+	 * Check if thread group timers expired when the cputimer is
+	 * running and no other thread in the group is already checking
+	 * for thread group cputimers. These fields are read without the
+	 * sighand lock. However, this is fine because this is meant to
+	 * be a fastpath heuristic to determine whether we should try to
+	 * acquire the sighand lock to check/handle timers.
+	 *
+	 * In the worst case scenario, if 'running' or 'checking_timer' gets
+	 * set but the current thread doesn't see the change yet, we'll wait
+	 * until the next thread in the group gets a scheduler interrupt to
+	 * handle the timer. This isn't an issue in practice because these
+	 * types of delays with signals actually getting sent are expected.
+	 */
+	if (READ_ONCE(sig->cputimer.running) &&
+	    !READ_ONCE(sig->cputimer.checking_timer)) {
 		struct task_cputime group_sample;
 
 		sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
@@ -1174,12 +1205,8 @@ void run_posix_cpu_timers(struct task_struct *tsk)
 	 * put them on the firing list.
 	 */
 	check_thread_timers(tsk, &firing);
-	/*
-	 * If there are any active process wide timers (POSIX 1.b, itimers,
-	 * RLIMIT_CPU) cputimer must be running.
-	 */
-	if (READ_ONCE(tsk->signal->cputimer.running))
-		check_process_timers(tsk, &firing);
+
+	check_process_timers(tsk, &firing);
 
 	/*
 	 * We must release these locks before taking any timer's lock.

kernel/time/timeconst.bc

@@ -39,7 +39,7 @@ define fmuls(b,n,d) {
 }
 
 define timeconst(hz) {
-	print "/* Automatically generated by kernel/timeconst.bc */\n"
+	print "/* Automatically generated by kernel/time/timeconst.bc */\n"
 	print "/* Time conversion constants for HZ == ", hz, " */\n"
 	print "\n"
 

kernel/time/timekeeping.c

@@ -849,7 +849,7 @@ EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
 #ifdef CONFIG_NTP_PPS
 
 /**
- * getnstime_raw_and_real - get day and raw monotonic time in timespec format
+ * ktime_get_raw_and_real_ts64 - get day and raw monotonic time in timespec format
  * @ts_raw:	pointer to the timespec to be set to raw monotonic time
  * @ts_real:	pointer to the timespec to be set to the time of day
  *
@@ -857,7 +857,7 @@ EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
  * same time atomically and stores the resulting timestamps in timespec
  * format.
  */
-void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
+void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw, struct timespec64 *ts_real)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned long seq;
@@ -868,7 +868,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
 	do {
 		seq = read_seqcount_begin(&tk_core.seq);
 
-		*ts_raw = timespec64_to_timespec(tk->raw_time);
+		*ts_raw = tk->raw_time;
 		ts_real->tv_sec = tk->xtime_sec;
 		ts_real->tv_nsec = 0;
 
@@ -877,10 +877,10 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
 
 	} while (read_seqcount_retry(&tk_core.seq, seq));
 
-	timespec_add_ns(ts_raw, nsecs_raw);
-	timespec_add_ns(ts_real, nsecs_real);
+	timespec64_add_ns(ts_raw, nsecs_raw);
+	timespec64_add_ns(ts_real, nsecs_real);
 }
-EXPORT_SYMBOL(getnstime_raw_and_real);
+EXPORT_SYMBOL(ktime_get_raw_and_real_ts64);
 
 #endif /* CONFIG_NTP_PPS */
 
@@ -1674,7 +1674,7 @@ static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
 /**
  * accumulate_nsecs_to_secs - Accumulates nsecs into secs
  *
- * Helper function that accumulates a the nsecs greater then a second
+ * Helper function that accumulates the nsecs greater than a second
  * from the xtime_nsec field to the xtime_secs field.
  * It also calls into the NTP code to handle leapsecond processing.
  *
@@ -1726,7 +1726,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
 	cycle_t interval = tk->cycle_interval << shift;
 	u64 raw_nsecs;
 
-	/* If the offset is smaller then a shifted interval, do nothing */
+	/* If the offset is smaller than a shifted interval, do nothing */
 	if (offset < interval)
 		return offset;
 
@@ -2025,7 +2025,7 @@ int do_adjtimex(struct timex *txc)
 /**
  * hardpps() - Accessor function to NTP __hardpps function
  */
-void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
+void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
 {
 	unsigned long flags;
 

kernel/time/timer.c

@@ -461,10 +461,17 @@ void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
 
 static void timer_stats_account_timer(struct timer_list *timer)
 {
-	if (likely(!timer->start_site))
+	void *site;
+
+	/*
+	 * start_site can be concurrently reset by
+	 * timer_stats_timer_clear_start_info()
+	 */
+	site = READ_ONCE(timer->start_site);
+	if (likely(!site))
 		return;
 
-	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+	timer_stats_update_stats(timer, timer->start_pid, site,
 				 timer->function, timer->start_comm,
 				 timer->flags);
 }
@@ -867,7 +874,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
 	if (mask == 0)
 		return expires;
 
-	bit = find_last_bit(&mask, BITS_PER_LONG);
+	bit = __fls(mask);
 
 	mask = (1UL << bit) - 1;
 

tools/testing/selftests/timers/Makefile

@@ -8,7 +8,7 @@ LDFLAGS += -lrt -lpthread
 TEST_PROGS = posix_timers nanosleep nsleep-lat set-timer-lat mqueue-lat \
 	     inconsistency-check raw_skew threadtest rtctest
 
-TEST_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex change_skew \
+TEST_PROGS_EXTENDED = alarmtimer-suspend valid-adjtimex adjtick change_skew \
 		      skew_consistency clocksource-switch leap-a-day \
 		      leapcrash set-tai set-2038
 
@@ -24,6 +24,7 @@ include ../lib.mk
 run_destructive_tests: run_tests
 	./alarmtimer-suspend
 	./valid-adjtimex
+	./adjtick
 	./change_skew
 	./skew_consistency
 	./clocksource-switch

tools/testing/selftests/timers/adjtick.c

@@ -0,0 +1,221 @@
+/* adjtimex() tick adjustment test
+ *		by:   John Stultz <john.stultz@linaro.org>
+ *		(C) Copyright Linaro Limited 2015
+ *		Licensed under the GPLv2
+ *
+ *  To build:
+ *	$ gcc adjtick.c -o adjtick -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 <unistd.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <time.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 CLOCK_MONOTONIC_RAW	4
+
+#define NSEC_PER_SEC		1000000000LL
+#define USEC_PER_SEC		1000000
+
+#define MILLION			1000000
+
+long systick;
+
+long long llabs(long long val)
+{
+	if (val < 0)
+		val = -val;
+	return val;
+}
+
+unsigned long long ts_to_nsec(struct timespec ts)
+{
+	return ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec;
+}
+
+struct timespec nsec_to_ts(long long ns)
+{
+	struct timespec ts;
+
+	ts.tv_sec = ns/NSEC_PER_SEC;
+	ts.tv_nsec = ns%NSEC_PER_SEC;
+
+	return ts;
+}
+
+long long diff_timespec(struct timespec start, struct timespec end)
+{
+	long long start_ns, end_ns;
+
+	start_ns = ts_to_nsec(start);
+	end_ns = ts_to_nsec(end);
+
+	return end_ns - start_ns;
+}
+
+void get_monotonic_and_raw(struct timespec *mon, struct timespec *raw)
+{
+	struct timespec start, mid, end;
+	long long diff = 0, tmp;
+	int i;
+
+	clock_gettime(CLOCK_MONOTONIC, mon);
+	clock_gettime(CLOCK_MONOTONIC_RAW, raw);
+
+	/* Try to get a more tightly bound pairing */
+	for (i = 0; i < 3; i++) {
+		long long newdiff;
+
+		clock_gettime(CLOCK_MONOTONIC, &start);
+		clock_gettime(CLOCK_MONOTONIC_RAW, &mid);
+		clock_gettime(CLOCK_MONOTONIC, &end);
+
+		newdiff = diff_timespec(start, end);
+		if (diff == 0 || newdiff < diff) {
+			diff = newdiff;
+			*raw = mid;
+			tmp = (ts_to_nsec(start) + ts_to_nsec(end))/2;
+			*mon = nsec_to_ts(tmp);
+		}
+	}
+}
+
+long long get_ppm_drift(void)
+{
+	struct timespec mon_start, raw_start, mon_end, raw_end;
+	long long delta1, delta2, eppm;
+
+	get_monotonic_and_raw(&mon_start, &raw_start);
+
+	sleep(15);
+
+	get_monotonic_and_raw(&mon_end, &raw_end);
+
+	delta1 = diff_timespec(mon_start, mon_end);
+	delta2 = diff_timespec(raw_start, raw_end);
+
+	eppm = (delta1*MILLION)/delta2 - MILLION;
+
+	return eppm;
+}
+
+int check_tick_adj(long tickval)
+{
+	long long eppm, ppm;
+	struct timex tx1;
+
+	tx1.modes	 = ADJ_TICK;
+	tx1.modes	|= ADJ_OFFSET;
+	tx1.modes	|= ADJ_FREQUENCY;
+	tx1.modes	|= ADJ_STATUS;
+
+	tx1.status	= STA_PLL;
+	tx1.offset	= 0;
+	tx1.freq	= 0;
+	tx1.tick	= tickval;
+
+	adjtimex(&tx1);
+
+	sleep(1);
+
+	ppm = ((long long)tickval * MILLION)/systick - MILLION;
+	printf("Estimating tick (act: %ld usec, %lld ppm): ", tickval, ppm);
+
+	eppm = get_ppm_drift();
+	printf("%lld usec, %lld ppm", systick + (systick * eppm / MILLION), eppm);
+
+	tx1.modes = 0;
+	adjtimex(&tx1);
+
+	if (tx1.offset || tx1.freq || tx1.tick != tickval) {
+		printf("	[ERROR]\n");
+		printf("\tUnexpected adjtimex return values, make sure ntpd is not running.\n");
+		return -1;
+	}
+
+	/*
+	 * Here we use 100ppm difference as an error bound.
+	 * We likely should see better, but some coarse clocksources
+	 * cannot match the HZ tick size accurately, so we have a
+	 * internal correction factor that doesn't scale exactly
+	 * with the adjustment, resulting in > 10ppm error during
+	 * a 10% adjustment. 100ppm also gives us more breathing
+	 * room for interruptions during the measurement.
+	 */
+	if (llabs(eppm - ppm) > 100) {
+		printf("	[FAILED]\n");
+		return -1;
+	}
+	printf("	[OK]\n");
+
+	return  0;
+}
+
+int main(int argv, char **argc)
+{
+	struct timespec raw;
+	long tick, max, interval, err;
+	struct timex tx1;
+
+	err = 0;
+	setbuf(stdout, NULL);
+
+	if (clock_gettime(CLOCK_MONOTONIC_RAW, &raw)) {
+		printf("ERR: NO CLOCK_MONOTONIC_RAW\n");
+		return -1;
+	}
+
+	printf("Each iteration takes about 15 seconds\n");
+
+	systick = sysconf(_SC_CLK_TCK);
+	systick = USEC_PER_SEC/sysconf(_SC_CLK_TCK);
+	max = systick/10; /* +/- 10% */
+	interval = max/4; /* in 4 steps each side */
+
+	for (tick = (systick - max); tick < (systick + max); tick += interval) {
+		if (check_tick_adj(tick)) {
+			err = 1;
+			break;
+		}
+	}
+
+	/* Reset things to zero */
+	tx1.modes	 = ADJ_TICK;
+	tx1.modes	|= ADJ_OFFSET;
+	tx1.modes	|= ADJ_FREQUENCY;
+
+	tx1.offset	 = 0;
+	tx1.freq	 = 0;
+	tx1.tick	 = systick;
+
+	adjtimex(&tx1);
+
+	if (err)
+		return ksft_exit_fail();
+
+	return ksft_exit_pass();
+}