Date:   Mon, 3 Oct 2016 19:17:09 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
cc:     LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [GIT pull] timer updates for 4,9

Linus,

please pull the latest timers-core-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-core-for-linus

A rather smalish set of updates for timers and timekeeping:

  - Two core fixes to prevent potential undefinded behaviour about which
    gcc is complaining rightfully.

  - A fix to prevent stopping the tick on an (soon) offline CPU so it can
    complete the shutdown procedure.

  - Wait for clocks to stabilize before making decisions, so a not yet
    validated clock is not rejected.

  - The usual pile of fixes to the various clocksource drivers.

  - Core code typo and include fixlets.


Thanks,

	tglx

------------------>
Alexandre Belloni (3):
      clocksource/drivers/timer-atmel-pit: Drop at91sam926x_pit_common_init
      clocksource/drivers/timer-atmel-pit: Remove uselesss WARN_ON_ONCE
      clocksource/drivers/timer-atmel-pit: Simplify IRQ handler

Christoph Hellwig (1):
      timekeeping: Include the correct header for errno definitions

Daniel Lezcano (2):
      clocksource/drivers/moxart: Replace setup_irq by request_irq
      clocksource/drivers/moxart: Replace panic by pr_err

Jisheng Zhang (1):
      clocksource/drivers/ti-32k: Prevent ftrace recursion

Joel Stanley (3):
      clocksource/drivers/moxart: Refactor enable/disable
      clocksource/drivers/moxart: Use struct to hold state
      clocksource/drivers/moxart: Add Aspeed support

Kyle Walker (1):
      clocksource: Defer override invalidation unless clock is unstable

Neil Armstrong (1):
      clocksource/drivers/oxnas: Add OX820 compatible

Paul Burton (2):
      clocksource/mips-gic-timer: Print an error if IRQ setup fails
      clocksource/mips-gic-timer: Stop checking cpu_has_counter

Pratyush Patel (1):
      hrtimer: Spelling fixes

Ruchi Kandoi (1):
      timekeeping: Prints the amounts of time spent during suspend

Vegard Nossum (2):
      time: Avoid undefined behaviour in timespec64_add_safe()
      time: Avoid undefined behaviour in ktime_add_safe()

Wanpeng Li (1):
      tick/nohz: Prevent stopping the tick on an offline CPU


 .../bindings/timer/moxa,moxart-timer.txt           |   4 +-
 .../devicetree/bindings/timer/oxsemi,rps-timer.txt |   2 +-
 drivers/clocksource/mips-gic-timer.c               |   7 +-
 drivers/clocksource/moxart_timer.c                 | 193 ++++++++++++++-------
 drivers/clocksource/timer-atmel-pit.c              |  96 ++++------
 drivers/clocksource/timer-oxnas-rps.c              |   2 +
 drivers/clocksource/timer-ti-32k.c                 |   2 +-
 include/linux/ktime.h                              |   7 +
 include/linux/time64.h                             |   1 +
 include/linux/timekeeping.h                        |   2 +-
 kernel/time/clocksource.c                          |  15 +-
 kernel/time/hrtimer.c                              |   6 +-
 kernel/time/tick-sched.c                           |   7 +-
 kernel/time/time.c                                 |   2 +-
 kernel/time/timekeeping_debug.c                    |   2 +
 15 files changed, 210 insertions(+), 138 deletions(-)

diff --git a/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt b/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
index da2d510cae47..e207c11630af 100644
--- a/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
+++ b/Documentation/devicetree/bindings/timer/moxa,moxart-timer.txt
@@ -2,7 +2,9 @@ MOXA ART timer
 
 Required properties:
 
-- compatible : Must be "moxa,moxart-timer"
+- compatible : Must be one of:
+ 	- "moxa,moxart-timer"
+ 	- "aspeed,ast2400-timer"
 - reg : Should contain registers location and length
 - interrupts : Should contain the timer interrupt number
 - clocks : Should contain phandle for the clock that drives the counter
diff --git a/Documentation/devicetree/bindings/timer/oxsemi,rps-timer.txt b/Documentation/devicetree/bindings/timer/oxsemi,rps-timer.txt
index 3ca89cd1caef..d191612539e8 100644
--- a/Documentation/devicetree/bindings/timer/oxsemi,rps-timer.txt
+++ b/Documentation/devicetree/bindings/timer/oxsemi,rps-timer.txt
@@ -2,7 +2,7 @@ Oxford Semiconductor OXNAS SoCs Family RPS Timer
 ================================================
 
 Required properties:
-- compatible: Should be "oxsemi,ox810se-rps-timer"
+- compatible: Should be "oxsemi,ox810se-rps-timer" or "oxsemi,ox820-rps-timer"
 - reg : Specifies base physical address and size of the registers.
 - interrupts : The interrupts of the two timers
 - clocks : The phandle of the timer clock source
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index b4b3ab5a11ad..7a960cd01104 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -109,12 +109,15 @@ static int gic_clockevent_init(void)
 {
 	int ret;
 
-	if (!cpu_has_counter || !gic_frequency)
+	if (!gic_frequency)
 		return -ENXIO;
 
 	ret = setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction);
-	if (ret < 0)
+	if (ret < 0) {
+		pr_err("GIC timer IRQ %d setup failed: %d\n",
+		       gic_timer_irq, ret);
 		return ret;
+	}
 
 	cpuhp_setup_state(CPUHP_AP_MIPS_GIC_TIMER_STARTING,
 			  "AP_MIPS_GIC_TIMER_STARTING", gic_starting_cpu,
diff --git a/drivers/clocksource/moxart_timer.c b/drivers/clocksource/moxart_timer.c
index 841454417acd..2a8f4705c734 100644
--- a/drivers/clocksource/moxart_timer.c
+++ b/drivers/clocksource/moxart_timer.c
@@ -21,6 +21,7 @@
 #include <linux/io.h>
 #include <linux/clocksource.h>
 #include <linux/bitops.h>
+#include <linux/slab.h>
 
 #define TIMER1_BASE		0x00
 #define TIMER2_BASE		0x10
@@ -36,75 +37,109 @@
 #define TIMER_INTR_MASK		0x38
 
 /*
- * TIMER_CR flags:
+ * Moxart TIMER_CR flags:
  *
- * TIMEREG_CR_*_CLOCK	0: PCLK, 1: EXT1CLK
- * TIMEREG_CR_*_INT	overflow interrupt enable bit
+ * MOXART_CR_*_CLOCK	0: PCLK, 1: EXT1CLK
+ * MOXART_CR_*_INT	overflow interrupt enable bit
  */
-#define TIMEREG_CR_1_ENABLE	BIT(0)
-#define TIMEREG_CR_1_CLOCK	BIT(1)
-#define TIMEREG_CR_1_INT	BIT(2)
-#define TIMEREG_CR_2_ENABLE	BIT(3)
-#define TIMEREG_CR_2_CLOCK	BIT(4)
-#define TIMEREG_CR_2_INT	BIT(5)
-#define TIMEREG_CR_3_ENABLE	BIT(6)
-#define TIMEREG_CR_3_CLOCK	BIT(7)
-#define TIMEREG_CR_3_INT	BIT(8)
-#define TIMEREG_CR_COUNT_UP	BIT(9)
-
-#define TIMER1_ENABLE		(TIMEREG_CR_2_ENABLE | TIMEREG_CR_1_ENABLE)
-#define TIMER1_DISABLE		(TIMEREG_CR_2_ENABLE)
-
-static void __iomem *base;
-static unsigned int clock_count_per_tick;
+#define MOXART_CR_1_ENABLE	BIT(0)
+#define MOXART_CR_1_CLOCK	BIT(1)
+#define MOXART_CR_1_INT	BIT(2)
+#define MOXART_CR_2_ENABLE	BIT(3)
+#define MOXART_CR_2_CLOCK	BIT(4)
+#define MOXART_CR_2_INT	BIT(5)
+#define MOXART_CR_3_ENABLE	BIT(6)
+#define MOXART_CR_3_CLOCK	BIT(7)
+#define MOXART_CR_3_INT	BIT(8)
+#define MOXART_CR_COUNT_UP	BIT(9)
+
+#define MOXART_TIMER1_ENABLE	(MOXART_CR_2_ENABLE | MOXART_CR_1_ENABLE)
+#define MOXART_TIMER1_DISABLE	(MOXART_CR_2_ENABLE)
+
+/*
+ * The ASpeed variant of the IP block has a different layout
+ * for the control register
+ */
+#define ASPEED_CR_1_ENABLE	BIT(0)
+#define ASPEED_CR_1_CLOCK	BIT(1)
+#define ASPEED_CR_1_INT		BIT(2)
+#define ASPEED_CR_2_ENABLE	BIT(4)
+#define ASPEED_CR_2_CLOCK	BIT(5)
+#define ASPEED_CR_2_INT		BIT(6)
+#define ASPEED_CR_3_ENABLE	BIT(8)
+#define ASPEED_CR_3_CLOCK	BIT(9)
+#define ASPEED_CR_3_INT		BIT(10)
+
+#define ASPEED_TIMER1_ENABLE   (ASPEED_CR_2_ENABLE | ASPEED_CR_1_ENABLE)
+#define ASPEED_TIMER1_DISABLE  (ASPEED_CR_2_ENABLE)
+
+struct moxart_timer {
+	void __iomem *base;
+	unsigned int t1_disable_val;
+	unsigned int t1_enable_val;
+	unsigned int count_per_tick;
+	struct clock_event_device clkevt;
+};
+
+static inline struct moxart_timer *to_moxart(struct clock_event_device *evt)
+{
+	return container_of(evt, struct moxart_timer, clkevt);
+}
+
+static inline void moxart_disable(struct clock_event_device *evt)
+{
+	struct moxart_timer *timer = to_moxart(evt);
+
+	writel(timer->t1_disable_val, timer->base + TIMER_CR);
+}
+
+static inline void moxart_enable(struct clock_event_device *evt)
+{
+	struct moxart_timer *timer = to_moxart(evt);
+
+	writel(timer->t1_enable_val, timer->base + TIMER_CR);
+}
 
 static int moxart_shutdown(struct clock_event_device *evt)
 {
-	writel(TIMER1_DISABLE, base + TIMER_CR);
+	moxart_disable(evt);
 	return 0;
 }
 
 static int moxart_set_oneshot(struct clock_event_device *evt)
 {
-	writel(TIMER1_DISABLE, base + TIMER_CR);
-	writel(~0, base + TIMER1_BASE + REG_LOAD);
+	moxart_disable(evt);
+	writel(~0, to_moxart(evt)->base + TIMER1_BASE + REG_LOAD);
 	return 0;
 }
 
 static int moxart_set_periodic(struct clock_event_device *evt)
 {
-	writel(clock_count_per_tick, base + TIMER1_BASE + REG_LOAD);
-	writel(TIMER1_ENABLE, base + TIMER_CR);
+	struct moxart_timer *timer = to_moxart(evt);
+
+	moxart_disable(evt);
+	writel(timer->count_per_tick, timer->base + TIMER1_BASE + REG_LOAD);
+	writel(0, timer->base + TIMER1_BASE + REG_MATCH1);
+	moxart_enable(evt);
 	return 0;
 }
 
 static int moxart_clkevt_next_event(unsigned long cycles,
-				    struct clock_event_device *unused)
+				    struct clock_event_device *evt)
 {
+	struct moxart_timer *timer = to_moxart(evt);
 	u32 u;
 
-	writel(TIMER1_DISABLE, base + TIMER_CR);
+	moxart_disable(evt);
 
-	u = readl(base + TIMER1_BASE + REG_COUNT) - cycles;
-	writel(u, base + TIMER1_BASE + REG_MATCH1);
+	u = readl(timer->base + TIMER1_BASE + REG_COUNT) - cycles;
+	writel(u, timer->base + TIMER1_BASE + REG_MATCH1);
 
-	writel(TIMER1_ENABLE, base + TIMER_CR);
+	moxart_enable(evt);
 
 	return 0;
 }
 
-static struct clock_event_device moxart_clockevent = {
-	.name			= "moxart_timer",
-	.rating			= 200,
-	.features		= CLOCK_EVT_FEAT_PERIODIC |
-				  CLOCK_EVT_FEAT_ONESHOT,
-	.set_state_shutdown	= moxart_shutdown,
-	.set_state_periodic	= moxart_set_periodic,
-	.set_state_oneshot	= moxart_set_oneshot,
-	.tick_resume		= moxart_set_oneshot,
-	.set_next_event		= moxart_clkevt_next_event,
-};
-
 static irqreturn_t moxart_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = dev_id;
@@ -112,21 +147,19 @@ static irqreturn_t moxart_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static struct irqaction moxart_timer_irq = {
-	.name		= "moxart-timer",
-	.flags		= IRQF_TIMER,
-	.handler	= moxart_timer_interrupt,
-	.dev_id		= &moxart_clockevent,
-};
-
 static int __init moxart_timer_init(struct device_node *node)
 {
 	int ret, irq;
 	unsigned long pclk;
 	struct clk *clk;
+	struct moxart_timer *timer;
+
+	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
+	if (!timer)
+		return -ENOMEM;
 
-	base = of_iomap(node, 0);
-	if (!base) {
+	timer->base = of_iomap(node, 0);
+	if (!timer->base) {
 		pr_err("%s: of_iomap failed\n", node->full_name);
 		return -ENXIO;
 	}
@@ -137,12 +170,6 @@ static int __init moxart_timer_init(struct device_node *node)
 		return -EINVAL;
 	}
 
-	ret = setup_irq(irq, &moxart_timer_irq);
-	if (ret) {
-		pr_err("%s: setup_irq failed\n", node->full_name);
-		return ret;
-	}
-
 	clk = of_clk_get(node, 0);
 	if (IS_ERR(clk))  {
 		pr_err("%s: of_clk_get failed\n", node->full_name);
@@ -151,7 +178,32 @@ static int __init moxart_timer_init(struct device_node *node)
 
 	pclk = clk_get_rate(clk);
 
-	ret = clocksource_mmio_init(base + TIMER2_BASE + REG_COUNT,
+	if (of_device_is_compatible(node, "moxa,moxart-timer")) {
+		timer->t1_enable_val = MOXART_TIMER1_ENABLE;
+		timer->t1_disable_val = MOXART_TIMER1_DISABLE;
+	} else if (of_device_is_compatible(node, "aspeed,ast2400-timer")) {
+		timer->t1_enable_val = ASPEED_TIMER1_ENABLE;
+		timer->t1_disable_val = ASPEED_TIMER1_DISABLE;
+	} else {
+		pr_err("%s: unknown platform\n", node->full_name);
+		return -EINVAL;
+	}
+
+	timer->count_per_tick = DIV_ROUND_CLOSEST(pclk, HZ);
+
+	timer->clkevt.name = node->name;
+	timer->clkevt.rating = 200;
+	timer->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
+					CLOCK_EVT_FEAT_ONESHOT;
+	timer->clkevt.set_state_shutdown = moxart_shutdown;
+	timer->clkevt.set_state_periodic = moxart_set_periodic;
+	timer->clkevt.set_state_oneshot = moxart_set_oneshot;
+	timer->clkevt.tick_resume = moxart_set_oneshot;
+	timer->clkevt.set_next_event = moxart_clkevt_next_event;
+	timer->clkevt.cpumask = cpumask_of(0);
+	timer->clkevt.irq = irq;
+
+	ret = clocksource_mmio_init(timer->base + TIMER2_BASE + REG_COUNT,
 				    "moxart_timer", pclk, 200, 32,
 				    clocksource_mmio_readl_down);
 	if (ret) {
@@ -159,13 +211,26 @@ static int __init moxart_timer_init(struct device_node *node)
 		return ret;
 	}
 
-	clock_count_per_tick = DIV_ROUND_CLOSEST(pclk, HZ);
+	ret = request_irq(irq, moxart_timer_interrupt, IRQF_TIMER,
+			  node->name, &timer->clkevt);
+	if (ret) {
+		pr_err("%s: setup_irq failed\n", node->full_name);
+		return ret;
+	}
 
-	writel(~0, base + TIMER2_BASE + REG_LOAD);
-	writel(TIMEREG_CR_2_ENABLE, base + TIMER_CR);
+	/* Clear match registers */
+	writel(0, timer->base + TIMER1_BASE + REG_MATCH1);
+	writel(0, timer->base + TIMER1_BASE + REG_MATCH2);
+	writel(0, timer->base + TIMER2_BASE + REG_MATCH1);
+	writel(0, timer->base + TIMER2_BASE + REG_MATCH2);
 
-	moxart_clockevent.cpumask = cpumask_of(0);
-	moxart_clockevent.irq = irq;
+	/*
+	 * Start timer 2 rolling as our main wall clock source, keep timer 1
+	 * disabled
+	 */
+	writel(0, timer->base + TIMER_CR);
+	writel(~0, timer->base + TIMER2_BASE + REG_LOAD);
+	writel(timer->t1_disable_val, timer->base + TIMER_CR);
 
 	/*
 	 * documentation is not publicly available:
@@ -173,9 +238,9 @@ static int __init moxart_timer_init(struct device_node *node)
 	 * max_delta 0xfffffffe should be ok because count
 	 * register size is u32
 	 */
-	clockevents_config_and_register(&moxart_clockevent, pclk,
-					0x4, 0xfffffffe);
+	clockevents_config_and_register(&timer->clkevt, pclk, 0x4, 0xfffffffe);
 
 	return 0;
 }
 CLOCKSOURCE_OF_DECLARE(moxart, "moxa,moxart-timer", moxart_timer_init);
+CLOCKSOURCE_OF_DECLARE(aspeed, "aspeed,ast2400-timer", moxart_timer_init);
diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
index 7f0f5b26d8c5..6555821bbdae 100644
--- a/drivers/clocksource/timer-atmel-pit.c
+++ b/drivers/clocksource/timer-atmel-pit.c
@@ -149,24 +149,13 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 {
 	struct pit_data *data = dev_id;
 
-	/*
-	 * irqs should be disabled here, but as the irq is shared they are only
-	 * guaranteed to be off if the timer irq is registered first.
-	 */
-	WARN_ON_ONCE(!irqs_disabled());
-
 	/* The PIT interrupt may be disabled, and is shared */
 	if (clockevent_state_periodic(&data->clkevt) &&
 	    (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) {
-		unsigned nr_ticks;
-
 		/* Get number of ticks performed before irq, and ack it */
-		nr_ticks = PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
-		do {
-			data->cnt += data->cycle;
-			data->clkevt.event_handler(&data->clkevt);
-			nr_ticks--;
-		} while (nr_ticks);
+		data->cnt += data->cycle * PIT_PICNT(pit_read(data->base,
+							      AT91_PIT_PIVR));
+		data->clkevt.event_handler(&data->clkevt);
 
 		return IRQ_HANDLED;
 	}
@@ -177,11 +166,41 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 /*
  * Set up both clocksource and clockevent support.
  */
-static int __init at91sam926x_pit_common_init(struct pit_data *data)
+static int __init at91sam926x_pit_dt_init(struct device_node *node)
 {
-	unsigned long	pit_rate;
-	unsigned	bits;
-	int		ret;
+	unsigned long   pit_rate;
+	unsigned        bits;
+	int             ret;
+	struct pit_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->base = of_iomap(node, 0);
+	if (!data->base) {
+		pr_err("Could not map PIT address\n");
+		return -ENXIO;
+	}
+
+	data->mck = of_clk_get(node, 0);
+	if (IS_ERR(data->mck)) {
+		pr_err("Unable to get mck clk\n");
+		return PTR_ERR(data->mck);
+	}
+
+	ret = clk_prepare_enable(data->mck);
+	if (ret) {
+		pr_err("Unable to enable mck\n");
+		return ret;
+	}
+
+	/* Get the interrupts property */
+	data->irq = irq_of_parse_and_map(node, 0);
+	if (!data->irq) {
+		pr_err("Unable to get IRQ from DT\n");
+		return -EINVAL;
+	}
 
 	/*
 	 * Use our actual MCK to figure out how many MCK/16 ticks per
@@ -236,46 +255,5 @@ static int __init at91sam926x_pit_common_init(struct pit_data *data)
 
 	return 0;
 }
-
-static int __init at91sam926x_pit_dt_init(struct device_node *node)
-{
-	struct pit_data *data;
-	int ret;
-
-	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
-
-	data->base = of_iomap(node, 0);
-	if (!data->base) {
-		pr_err("Could not map PIT address\n");
-		return -ENXIO;
-	}
-
-	data->mck = of_clk_get(node, 0);
-	if (IS_ERR(data->mck))
-		/* Fallback on clkdev for !CCF-based boards */
-		data->mck = clk_get(NULL, "mck");
-
-	if (IS_ERR(data->mck)) {
-		pr_err("Unable to get mck clk\n");
-		return PTR_ERR(data->mck);
-	}
-
-	ret = clk_prepare_enable(data->mck);
-	if (ret) {
-		pr_err("Unable to enable mck\n");
-		return ret;
-	}
-
-	/* Get the interrupts property */
-	data->irq = irq_of_parse_and_map(node, 0);
-	if (!data->irq) {
-		pr_err("Unable to get IRQ from DT\n");
-		return -EINVAL;
-	}
-
-	return at91sam926x_pit_common_init(data);
-}
 CLOCKSOURCE_OF_DECLARE(at91sam926x_pit, "atmel,at91sam9260-pit",
 		       at91sam926x_pit_dt_init);
diff --git a/drivers/clocksource/timer-oxnas-rps.c b/drivers/clocksource/timer-oxnas-rps.c
index bd887e2a8cf8..d630bf417773 100644
--- a/drivers/clocksource/timer-oxnas-rps.c
+++ b/drivers/clocksource/timer-oxnas-rps.c
@@ -295,3 +295,5 @@ err_alloc:
 
 CLOCKSOURCE_OF_DECLARE(ox810se_rps,
 		       "oxsemi,ox810se-rps-timer", oxnas_rps_timer_init);
+CLOCKSOURCE_OF_DECLARE(ox820_rps,
+		       "oxsemi,ox820se-rps-timer", oxnas_rps_timer_init);
diff --git a/drivers/clocksource/timer-ti-32k.c b/drivers/clocksource/timer-ti-32k.c
index 92b7e390f6c8..cf5b14e442e4 100644
--- a/drivers/clocksource/timer-ti-32k.c
+++ b/drivers/clocksource/timer-ti-32k.c
@@ -65,7 +65,7 @@ static inline struct ti_32k *to_ti_32k(struct clocksource *cs)
 	return container_of(cs, struct ti_32k, cs);
 }
 
-static cycle_t ti_32k_read_cycles(struct clocksource *cs)
+static cycle_t notrace ti_32k_read_cycles(struct clocksource *cs)
 {
 	struct ti_32k *ti = to_ti_32k(cs);
 
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 2b6a204bd8d4..3ffc69ebe967 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -64,6 +64,13 @@ static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
 		({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
 
 /*
+ * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
+ * this means that you must check the result for overflow yourself.
+ */
+#define ktime_add_unsafe(lhs, rhs) \
+		({ (ktime_t){ .tv64 = (u64) (lhs).tv64 + (rhs).tv64 }; })
+
+/*
  * Add a ktime_t variable and a scalar nanosecond value.
  * res = kt + nsval:
  */
diff --git a/include/linux/time64.h b/include/linux/time64.h
index 7e5d2fa9ac46..980c71b3001a 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -5,6 +5,7 @@
 #include <linux/math64.h>
 
 typedef __s64 time64_t;
+typedef __u64 timeu64_t;
 
 /*
  * This wants to go into uapi/linux/time.h once we agreed about the
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 816b7543f81b..09168c52ab64 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -1,7 +1,7 @@
 #ifndef _LINUX_TIMEKEEPING_H
 #define _LINUX_TIMEKEEPING_H
 
-#include <asm-generic/errno-base.h>
+#include <linux/errno.h>
 
 /* Included from linux/ktime.h */
 
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 6a5a310a1a53..7e4fad75acaa 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -600,9 +600,18 @@ static void __clocksource_select(bool skipcur)
 		 */
 		if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) {
 			/* Override clocksource cannot be used. */
-			pr_warn("Override clocksource %s is not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
-				cs->name);
-			override_name[0] = 0;
+			if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+				pr_warn("Override clocksource %s is unstable and not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
+					cs->name);
+				override_name[0] = 0;
+			} else {
+				/*
+				 * The override cannot be currently verified.
+				 * Deferring to let the watchdog check.
+				 */
+				pr_info("Override clocksource %s is not currently HRT compatible - deferring\n",
+					cs->name);
+			}
 		} else
 			/* Override clocksource can be used. */
 			best = cs;
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 9ba7c820fc23..bb5ec425dfe0 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -307,7 +307,7 @@ EXPORT_SYMBOL_GPL(__ktime_divns);
  */
 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
 {
-	ktime_t res = ktime_add(lhs, rhs);
+	ktime_t res = ktime_add_unsafe(lhs, rhs);
 
 	/*
 	 * We use KTIME_SEC_MAX here, the maximum timeout which we can
@@ -703,7 +703,7 @@ static void clock_was_set_work(struct work_struct *work)
 static DECLARE_WORK(hrtimer_work, clock_was_set_work);
 
 /*
- * Called from timekeeping and resume code to reprogramm the hrtimer
+ * Called from timekeeping and resume code to reprogram the hrtimer
  * interrupt device on all cpus.
  */
 void clock_was_set_delayed(void)
@@ -1241,7 +1241,7 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
 
 	/*
 	 * Note: We clear the running state after enqueue_hrtimer and
-	 * we do not reprogramm the event hardware. Happens either in
+	 * we do not reprogram the event hardware. Happens either in
 	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
 	 *
 	 * Note: Because we dropped the cpu_base->lock above,
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2ec7c00228f3..3bcb61b52f6c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -186,10 +186,13 @@ static bool check_tick_dependency(atomic_t *dep)
 	return false;
 }
 
-static bool can_stop_full_tick(struct tick_sched *ts)
+static bool can_stop_full_tick(int cpu, struct tick_sched *ts)
 {
 	WARN_ON_ONCE(!irqs_disabled());
 
+	if (unlikely(!cpu_online(cpu)))
+		return false;
+
 	if (check_tick_dependency(&tick_dep_mask))
 		return false;
 
@@ -843,7 +846,7 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
 	if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
 		return;
 
-	if (can_stop_full_tick(ts))
+	if (can_stop_full_tick(cpu, ts))
 		tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
 	else if (ts->tick_stopped)
 		tick_nohz_restart_sched_tick(ts, ktime_get());
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 667b9335f5d6..bd62fb8e8e77 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -780,7 +780,7 @@ struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
 {
 	struct timespec64 res;
 
-	set_normalized_timespec64(&res, lhs.tv_sec + rhs.tv_sec,
+	set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
 			lhs.tv_nsec + rhs.tv_nsec);
 
 	if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c
index 107310a6f36f..ca9fb800336b 100644
--- a/kernel/time/timekeeping_debug.c
+++ b/kernel/time/timekeeping_debug.c
@@ -75,5 +75,7 @@ void tk_debug_account_sleep_time(struct timespec64 *t)
 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
 
 	sleep_time_bin[bin]++;
+	pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec,
+			t->tv_nsec / NSEC_PER_MSEC);
 }
 

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