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

Pull timer updates from Thomas Gleixner:
 "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"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Include the correct header for errno definitions
  clocksource/drivers/ti-32k: Prevent ftrace recursion
  clocksource/mips-gic-timer: Stop checking cpu_has_counter
  clocksource/mips-gic-timer: Print an error if IRQ setup fails
  tick/nohz: Prevent stopping the tick on an offline CPU
  clocksource/drivers/oxnas: Add OX820 compatible
  clocksource/drivers/timer-atmel-pit: Simplify IRQ handler
  clocksource/drivers/timer-atmel-pit: Remove uselesss WARN_ON_ONCE
  clocksource/drivers/timer-atmel-pit: Drop at91sam926x_pit_common_init
  clocksource/drivers/moxart: Replace panic by pr_err
  clocksource/drivers/moxart: Replace setup_irq by request_irq
  clocksource/drivers/moxart: Add Aspeed support
  clocksource/drivers/moxart: Use struct to hold state
  clocksource/drivers/moxart: Refactor enable/disable
  time: Avoid undefined behaviour in ktime_add_safe()
  time: Avoid undefined behaviour in timespec64_add_safe()
  timekeeping: Prints the amounts of time spent during suspend
  clocksource: Defer override invalidation unless clock is unstable
  hrtimer: Spelling fixes

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);
 }