Merge tag 'timers-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer and timekeeping updates from Thomas Gleixner:
 "Core code:

   - Make the NOHZ handling of the timekeeping/tick core more robust to
     prevent a rare jiffies update stall.

   - Handle softirqs in the NOHZ/idle case correctly

  Drivers:

   - Add support for event stream scaling of the 1GHz counter on ARM(64)

   - Correct an error code check in the timer-of layer

   - The usual cleanups and improvements all over the place"

* tag 'timers-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  lib/irq_poll: Declare IRQ_POLL softirq vector as ksoftirqd-parking safe
  tick/rcu: Stop allowing RCU_SOFTIRQ in idle
  tick/rcu: Remove obsolete rcu_needs_cpu() parameters
  tick: Detect and fix jiffies update stall
  clocksource/drivers/timer-of: Check return value of of_iomap in timer_of_base_init()
  clocksource/drivers/timer-microchip-pit64b: Use 5MHz for clockevent
  clocksource/drivers/timer-microchip-pit64b: Use notrace
  clocksource/drivers/timer-microchip-pit64b: Remove mmio selection
  dt-bindings: timer: Tegra: Convert text bindings to yaml
  clocksource/drivers/imx-tpm: Move tpm_read_sched_clock() under CONFIG_ARM
  clocksource/drivers/arm_arch_timer: Use event stream scaling when available
  clocksource/drivers/exynos_mct: Increase the size of name array
  clocksource/drivers/exynos_mct: Bump up mct max irq number
  clocksource/drivers/exynos_mct: Remove mct interrupt index enum
  clocksource/drivers/exynos_mct: Handle DTS with higher number of interrupts
  clocksource/drivers/timer-ti-dm: Fix regression from errata i940 fix
  clocksource/drivers/imx-tpm: Exclude sched clock for ARM64
  clocksource: Add a Kconfig option for WATCHDOG_MAX_SKEW
  clocksource/drivers/imx-tpm: Update name of clkevt
  clocksource/drivers/imx-tpm: Add CLOCK_EVT_FEAT_DYNIRQ
  ...

Documentation/devicetree/bindings/timer/nvidia,tegra-timer.yaml

+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/timer/nvidia,tegra-timer.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: NVIDIA Tegra timer
+
+maintainers:
+  - Stephen Warren <swarren@nvidia.com>
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nvidia,tegra210-timer
+    then:
+      properties:
+        interrupts:
+          # Either a single combined interrupt or up to 14 individual interrupts
+          minItems: 1
+          maxItems: 14
+          description: >
+            A list of 14 interrupts; one per each timer channels 0 through 13
+
+  - if:
+      properties:
+        compatible:
+          oneOf:
+            - items:
+                - enum:
+                    - nvidia,tegra114-timer
+                    - nvidia,tegra124-timer
+                    - nvidia,tegra132-timer
+                - const: nvidia,tegra30-timer
+            - items:
+                - const: nvidia,tegra30-timer
+                - const: nvidia,tegra20-timer
+    then:
+      properties:
+        interrupts:
+          # Either a single combined interrupt or up to 6 individual interrupts
+          minItems: 1
+          maxItems: 6
+          description: >
+            A list of 6 interrupts; one per each of timer channels 1 through 5,
+            and one for the shared interrupt for the remaining channels.
+
+  - if:
+      properties:
+        compatible:
+          const: nvidia,tegra20-timer
+    then:
+      properties:
+        interrupts:
+          # Either a single combined interrupt or up to 4 individual interrupts
+          minItems: 1
+          maxItems: 4
+          description: |
+            A list of 4 interrupts; one per timer channel.
+
+properties:
+  compatible:
+    oneOf:
+      - const: nvidia,tegra210-timer
+        description: >
+          The Tegra210 timer provides fourteen 29-bit timer counters and one 32-bit
+          timestamp counter. The TMRs run at either a fixed 1 MHz clock rate derived
+          from the oscillator clock (TMR0-TMR9) or directly at the oscillator clock
+          (TMR10-TMR13). Each TMR can be programmed to generate one-shot, periodic,
+          or watchdog interrupts.
+      - items:
+          - enum:
+              - nvidia,tegra114-timer
+              - nvidia,tegra124-timer
+              - nvidia,tegra132-timer
+          - const: nvidia,tegra30-timer
+      - items:
+          - const: nvidia,tegra30-timer
+          - const: nvidia,tegra20-timer
+        description: >
+          The Tegra30 timer provides ten 29-bit timer channels, a single 32-bit free
+          running counter, and 5 watchdog modules. The first two channels may also
+          trigger a legacy watchdog reset.
+      - const: nvidia,tegra20-timer
+        description: >
+          The Tegra20 timer provides four 29-bit timer channels and a single 32-bit free
+          running counter. The first two channels may also trigger a watchdog reset.
+
+  reg:
+    maxItems: 1
+
+  interrupts: true
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: timer
+
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    timer@60005000 {
+        compatible = "nvidia,tegra30-timer", "nvidia,tegra20-timer";
+        reg = <0x60005000 0x400>;
+        interrupts = <0 0 IRQ_TYPE_LEVEL_HIGH>,
+                     <0 1 IRQ_TYPE_LEVEL_HIGH>,
+                     <0 41 IRQ_TYPE_LEVEL_HIGH>,
+                     <0 42 IRQ_TYPE_LEVEL_HIGH>,
+                     <0 121 IRQ_TYPE_LEVEL_HIGH>,
+                     <0 122 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&tegra_car 214>;
+    };
+  - |
+    #include <dt-bindings/clock/tegra210-car.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    timer@60005000 {
+        compatible = "nvidia,tegra210-timer";
+        reg = <0x60005000 0x400>;
+        interrupts = <GIC_SPI 156 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 41 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 121 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 152 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 153 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 154 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 155 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 177 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 178 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 179 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&tegra_car TEGRA210_CLK_TIMER>;
+        clock-names = "timer";
+    };

Documentation/devicetree/bindings/timer/nvidia,tegra20-timer.txt

-NVIDIA Tegra20 timer
-
-The Tegra20 timer provides four 29-bit timer channels and a single 32-bit free
-running counter. The first two channels may also trigger a watchdog reset.
-
-Required properties:
-
-- compatible : should be "nvidia,tegra20-timer".
-- reg : Specifies base physical address and size of the registers.
-- interrupts : A list of 4 interrupts; one per timer channel.
-- clocks : Must contain one entry, for the module clock.
-  See ../clocks/clock-bindings.txt for details.
-
-Example:
-
-timer {
-	compatible = "nvidia,tegra20-timer";
-	reg = <0x60005000 0x60>;
-	interrupts = <0 0 0x04
-			0 1 0x04
-			0 41 0x04
-			0 42 0x04>;
-	clocks = <&tegra_car 132>;
-};

Documentation/devicetree/bindings/timer/nvidia,tegra210-timer.txt

-NVIDIA Tegra210 timer
-
-The Tegra210 timer provides fourteen 29-bit timer counters and one 32-bit
-timestamp counter. The TMRs run at either a fixed 1 MHz clock rate derived
-from the oscillator clock (TMR0-TMR9) or directly at the oscillator clock
-(TMR10-TMR13). Each TMR can be programmed to generate one-shot, periodic,
-or watchdog interrupts.
-
-Required properties:
-- compatible : "nvidia,tegra210-timer".
-- reg : Specifies base physical address and size of the registers.
-- interrupts : A list of 14 interrupts; one per each timer channels 0 through
-  13.
-- clocks : Must contain one entry, for the module clock.
-  See ../clocks/clock-bindings.txt for details.
-
-timer@60005000 {
-	compatible = "nvidia,tegra210-timer";
-	reg = <0x0 0x60005000 0x0 0x400>;
-	interrupts = <GIC_SPI 156 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 41 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 121 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 152 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 153 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 154 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 155 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 177 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 178 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 179 IRQ_TYPE_LEVEL_HIGH>;
-	clocks = <&tegra_car TEGRA210_CLK_TIMER>;
-	clock-names = "timer";
-};

Documentation/devicetree/bindings/timer/nvidia,tegra30-timer.txt

-NVIDIA Tegra30 timer
-
-The Tegra30 timer provides ten 29-bit timer channels, a single 32-bit free
-running counter, and 5 watchdog modules. The first two channels may also
-trigger a legacy watchdog reset.
-
-Required properties:
-
-- compatible : For Tegra30, must contain "nvidia,tegra30-timer".  Otherwise,
-  must contain '"nvidia,<chip>-timer", "nvidia,tegra30-timer"' where
-  <chip> is tegra124 or tegra132.
-- reg : Specifies base physical address and size of the registers.
-- interrupts : A list of 6 interrupts; one per each of timer channels 1
-    through 5, and one for the shared interrupt for the remaining channels.
-- clocks : Must contain one entry, for the module clock.
-  See ../clocks/clock-bindings.txt for details.
-
-timer {
-	compatible = "nvidia,tegra30-timer", "nvidia,tegra20-timer";
-	reg = <0x60005000 0x400>;
-	interrupts = <0 0 0x04
-		      0 1 0x04
-		      0 41 0x04
-		      0 42 0x04
-		      0 121 0x04
-		      0 122 0x04>;
-	clocks = <&tegra_car 214>;
-};

arch/arm/boot/dts/dra7-l4.dtsi

@@ -3482,8 +3482,7 @@
 				ti,timer-pwm;
 			};
 		};
-
-		target-module@2c000 {			/* 0x4882c000, ap 17 02.0 */
+		timer15_target: target-module@2c000 {	/* 0x4882c000, ap 17 02.0 */
 			compatible = "ti,sysc-omap4-timer", "ti,sysc";
 			reg = <0x2c000 0x4>,
 			      <0x2c010 0x4>;
@@ -3511,7 +3510,7 @@
 			};
 		};
 
-		target-module@2e000 {			/* 0x4882e000, ap 19 14.0 */
+		timer16_target: target-module@2e000 {	/* 0x4882e000, ap 19 14.0 */
 			compatible = "ti,sysc-omap4-timer", "ti,sysc";
 			reg = <0x2e000 0x4>,
 			      <0x2e010 0x4>;

arch/arm/boot/dts/dra7.dtsi

@@ -1339,20 +1339,20 @@
 };
 
 /* Local timers, see ARM architected timer wrap erratum i940 */
-&timer3_target {
+&timer15_target {
 	ti,no-reset-on-init;
 	ti,no-idle;
 	timer@0 {
-		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER3_CLKCTRL 24>;
+		assigned-clocks = <&l4per3_clkctrl DRA7_L4PER3_TIMER15_CLKCTRL 24>;
 		assigned-clock-parents = <&timer_sys_clk_div>;
 	};
 };
 
-&timer4_target {
+&timer16_target {
 	ti,no-reset-on-init;
 	ti,no-idle;
 	timer@0 {
-		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER4_CLKCTRL 24>;
+		assigned-clocks = <&l4per3_clkctrl DRA7_L4PER3_TIMER16_CLKCTRL 24>;
 		assigned-clock-parents = <&timer_sys_clk_div>;
 	};
 };

drivers/clocksource/Kconfig

@@ -713,7 +713,6 @@ config INGENIC_OST
 config MICROCHIP_PIT64B
 	bool "Microchip PIT64B support"
 	depends on OF || COMPILE_TEST
-	select CLKSRC_MMIO
 	select TIMER_OF
 	help
 	  This option enables Microchip PIT64B timer for Atmel

drivers/clocksource/arm_arch_timer.c

@@ -880,10 +880,19 @@ static void __arch_timer_setup(unsigned type,
 	clockevents_config_and_register(clk, arch_timer_rate, 0xf, max_delta);
 }
 
-static void arch_timer_evtstrm_enable(int divider)
+static void arch_timer_evtstrm_enable(unsigned int divider)
 {
 	u32 cntkctl = arch_timer_get_cntkctl();
 
+#ifdef CONFIG_ARM64
+	/* ECV is likely to require a large divider. Use the EVNTIS flag. */
+	if (cpus_have_const_cap(ARM64_HAS_ECV) && divider > 15) {
+		cntkctl |= ARCH_TIMER_EVT_INTERVAL_SCALE;
+		divider -= 8;
+	}
+#endif
+
+	divider = min(divider, 15U);
 	cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
 	/* Set the divider and enable virtual event stream */
 	cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
@@ -912,7 +921,7 @@ static void arch_timer_configure_evtstream(void)
 		lsb++;
 
 	/* enable event stream */
-	arch_timer_evtstrm_enable(max(0, min(lsb, 15)));
+	arch_timer_evtstrm_enable(max(0, lsb));
 }
 
 static void arch_counter_set_user_access(void)

drivers/clocksource/exynos_mct.c

@@ -60,27 +60,18 @@
 #define MCT_CLKEVENTS_RATING		350
 #endif
 
+/* There are four Global timers starting with 0 offset */
+#define MCT_G0_IRQ	0
+/* Local timers count starts after global timer count */
+#define MCT_L0_IRQ	4
+/* Max number of IRQ as per DT binding document */
+#define MCT_NR_IRQS	20
+
 enum {
 	MCT_INT_SPI,
 	MCT_INT_PPI
 };
 
-enum {
-	MCT_G0_IRQ,
-	MCT_G1_IRQ,
-	MCT_G2_IRQ,
-	MCT_G3_IRQ,
-	MCT_L0_IRQ,
-	MCT_L1_IRQ,
-	MCT_L2_IRQ,
-	MCT_L3_IRQ,
-	MCT_L4_IRQ,
-	MCT_L5_IRQ,
-	MCT_L6_IRQ,
-	MCT_L7_IRQ,
-	MCT_NR_IRQS,
-};
-
 static void __iomem *reg_base;
 static unsigned long clk_rate;
 static unsigned int mct_int_type;
@@ -89,7 +80,11 @@ static int mct_irqs[MCT_NR_IRQS];
 struct mct_clock_event_device {
 	struct clock_event_device evt;
 	unsigned long base;
-	char name[10];
+	/**
+	 *  The length of the name must be adjusted if number of
+	 *  local timer interrupts grow over two digits
+	 */
+	char name[11];
 };
 
 static void exynos4_mct_write(unsigned int value, unsigned long offset)
@@ -541,6 +536,11 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 	 * irqs are specified.
 	 */
 	nr_irqs = of_irq_count(np);
+	if (nr_irqs > ARRAY_SIZE(mct_irqs)) {
+		pr_err("exynos-mct: too many (%d) interrupts configured in DT\n",
+			nr_irqs);
+		nr_irqs = ARRAY_SIZE(mct_irqs);
+	}
 	for (i = MCT_L0_IRQ; i < nr_irqs; i++)
 		mct_irqs[i] = irq_of_parse_and_map(np, i);
 
@@ -553,11 +553,14 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 		     mct_irqs[MCT_L0_IRQ], err);
 	} else {
 		for_each_possible_cpu(cpu) {
-			int mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
+			int mct_irq;
 			struct mct_clock_event_device *pcpu_mevt =
 				per_cpu_ptr(&percpu_mct_tick, cpu);
 
 			pcpu_mevt->evt.irq = -1;
+			if (MCT_L0_IRQ + cpu >= ARRAY_SIZE(mct_irqs))
+				break;
+			mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
 
 			irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
 			if (request_irq(mct_irq,

drivers/clocksource/timer-imx-sysctr.c

@@ -110,7 +110,7 @@ static struct timer_of to_sysctr = {
 	},
 	.of_irq = {
 		.handler		= sysctr_timer_interrupt,
-		.flags			= IRQF_TIMER | IRQF_IRQPOLL,
+		.flags			= IRQF_TIMER,
 	},
 	.of_clk = {
 		.name = "per",

drivers/clocksource/timer-imx-tpm.c

@@ -32,8 +32,8 @@
 #define TPM_C0SC_CHF_MASK		(0x1 << 7)
 #define TPM_C0V				0x24
 
-static int counter_width;
-static void __iomem *timer_base;
+static int counter_width __ro_after_init;
+static void __iomem *timer_base __ro_after_init;
 
 static inline void tpm_timer_disable(void)
 {
@@ -73,12 +73,12 @@ static unsigned long tpm_read_current_timer(void)
 {
 	return tpm_read_counter();
 }
-#endif
 
 static u64 notrace tpm_read_sched_clock(void)
 {
 	return tpm_read_counter();
 }
+#endif
 
 static int tpm_set_next_event(unsigned long delta,
 				struct clock_event_device *evt)
@@ -127,9 +127,9 @@ static irqreturn_t tpm_timer_interrupt(int irq, void *dev_id)
 static struct timer_of to_tpm = {
 	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
 	.clkevt = {
-		.name			= "i.MX7ULP TPM Timer",
+		.name			= "i.MX TPM Timer",
 		.rating			= 200,
-		.features		= CLOCK_EVT_FEAT_ONESHOT,
+		.features		= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ,
 		.set_state_shutdown	= tpm_set_state_shutdown,
 		.set_state_oneshot	= tpm_set_state_oneshot,
 		.set_next_event		= tpm_set_next_event,
@@ -137,7 +137,7 @@ static struct timer_of to_tpm = {
 	},
 	.of_irq = {
 		.handler		= tpm_timer_interrupt,
-		.flags			= IRQF_TIMER | IRQF_IRQPOLL,
+		.flags			= IRQF_TIMER,
 	},
 	.of_clk = {
 		.name = "per",
@@ -150,10 +150,10 @@ static int __init tpm_clocksource_init(void)
 	tpm_delay_timer.read_current_timer = &tpm_read_current_timer;
 	tpm_delay_timer.freq = timer_of_rate(&to_tpm) >> 3;
 	register_current_timer_delay(&tpm_delay_timer);
-#endif
 
 	sched_clock_register(tpm_read_sched_clock, counter_width,
 			     timer_of_rate(&to_tpm) >> 3);
+#endif
 
 	return clocksource_mmio_init(timer_base + TPM_CNT,
 				     "imx-tpm",

drivers/clocksource/timer-microchip-pit64b.c

@@ -42,8 +42,7 @@
 #define MCHP_PIT64B_LSBMASK		GENMASK_ULL(31, 0)
 #define MCHP_PIT64B_PRES_TO_MODE(p)	(MCHP_PIT64B_MR_PRES & ((p) << 8))
 #define MCHP_PIT64B_MODE_TO_PRES(m)	((MCHP_PIT64B_MR_PRES & (m)) >> 8)
-#define MCHP_PIT64B_DEF_CS_FREQ		5000000UL	/* 5 MHz */
-#define MCHP_PIT64B_DEF_CE_FREQ		32768		/* 32 KHz */
+#define MCHP_PIT64B_DEF_FREQ		5000000UL	/* 5 MHz */
 
 #define MCHP_PIT64B_NAME		"pit64b"
 
@@ -165,7 +164,7 @@ static u64 mchp_pit64b_clksrc_read(struct clocksource *cs)
 	return mchp_pit64b_cnt_read(mchp_pit64b_cs_base);
 }
 
-static u64 mchp_pit64b_sched_read_clk(void)
+static u64 notrace mchp_pit64b_sched_read_clk(void)
 {
 	return mchp_pit64b_cnt_read(mchp_pit64b_cs_base);
 }
@@ -418,7 +417,6 @@ static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer,
 static int __init mchp_pit64b_dt_init_timer(struct device_node *node,
 					    bool clkevt)
 {
-	u32 freq = clkevt ? MCHP_PIT64B_DEF_CE_FREQ : MCHP_PIT64B_DEF_CS_FREQ;
 	struct mchp_pit64b_timer timer;
 	unsigned long clk_rate;
 	u32 irq = 0;
@@ -446,7 +444,7 @@ static int __init mchp_pit64b_dt_init_timer(struct device_node *node,
 	}
 
 	/* Initialize mode (prescaler + SGCK bit). To be used at runtime. */
-	ret = mchp_pit64b_init_mode(&timer, freq);
+	ret = mchp_pit64b_init_mode(&timer, MCHP_PIT64B_DEF_FREQ);
 	if (ret)
 		goto irq_unmap;
 

drivers/clocksource/timer-of.c

@@ -157,9 +157,9 @@ static __init int timer_of_base_init(struct device_node *np,
 	of_base->base = of_base->name ?
 		of_io_request_and_map(np, of_base->index, of_base->name) :
 		of_iomap(np, of_base->index);
-	if (IS_ERR(of_base->base)) {
-		pr_err("Failed to iomap (%s)\n", of_base->name);
-		return PTR_ERR(of_base->base);
+	if (IS_ERR_OR_NULL(of_base->base)) {
+		pr_err("Failed to iomap (%s:%s)\n", np->name, of_base->name);
+		return of_base->base ? PTR_ERR(of_base->base) : -ENOMEM;
 	}
 
 	return 0;

drivers/clocksource/timer-ti-dm-systimer.c

@@ -694,9 +694,9 @@ static int __init dmtimer_percpu_quirk_init(struct device_node *np, u32 pa)
 		return 0;
 	}
 
-	if (pa == 0x48034000)		/* dra7 dmtimer3 */
+	if (pa == 0x4882c000)           /* dra7 dmtimer15 */
 		return dmtimer_percpu_timer_init(np, 0);
-	else if (pa == 0x48036000)	/* dra7 dmtimer4 */
+	else if (pa == 0x4882e000)      /* dra7 dmtimer16 */
 		return dmtimer_percpu_timer_init(np, 1);
 
 	return 0;

include/clocksource/arm_arch_timer.h

@@ -56,6 +56,7 @@ enum arch_timer_spi_nr {
 #define ARCH_TIMER_EVT_TRIGGER_MASK	(0xF << ARCH_TIMER_EVT_TRIGGER_SHIFT)
 #define ARCH_TIMER_USR_VT_ACCESS_EN	(1 << 8) /* virtual timer registers */
 #define ARCH_TIMER_USR_PT_ACCESS_EN	(1 << 9) /* physical timer registers */
+#define ARCH_TIMER_EVT_INTERVAL_SCALE	(1 << 17) /* EVNTIS in the ARMv8 ARM */
 
 #define ARCH_TIMER_EVT_STREAM_PERIOD_US	100
 #define ARCH_TIMER_EVT_STREAM_FREQ				\

include/linux/interrupt.h

@@ -579,7 +579,16 @@ enum
 	NR_SOFTIRQS
 };
 
-#define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
+/*
+ * The following vectors can be safely ignored after ksoftirqd is parked:
+ *
+ * _ RCU:
+ * 	1) rcutree_migrate_callbacks() migrates the queue.
+ * 	2) rcu_report_dead() reports the final quiescent states.
+ *
+ * _ IRQ_POLL: irq_poll_cpu_dead() migrates the queue
+ */
+#define SOFTIRQ_HOTPLUG_SAFE_MASK (BIT(RCU_SOFTIRQ) | BIT(IRQ_POLL_SOFTIRQ))
 
 /* map softirq index to softirq name. update 'softirq_to_name' in
  * kernel/softirq.c when adding a new softirq.

include/linux/rcutiny.h

@@ -64,9 +64,8 @@ static inline void rcu_softirq_qs(void)
 		rcu_tasks_qs(current, (preempt)); \
 	} while (0)
 
-static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt)
+static inline int rcu_needs_cpu(void)
 {
-	*nextevt = KTIME_MAX;
 	return 0;
 }
 

include/linux/rcutree.h

@@ -19,7 +19,7 @@
 
 void rcu_softirq_qs(void);
 void rcu_note_context_switch(bool preempt);
-int rcu_needs_cpu(u64 basem, u64 *nextevt);
+int rcu_needs_cpu(void);
 void rcu_cpu_stall_reset(void);
 
 /*

kernel/rcu/tree.c

@@ -1086,9 +1086,8 @@ void rcu_irq_enter_irqson(void)
  * Just check whether or not this CPU has non-offloaded RCU callbacks
  * queued.
  */
-int rcu_needs_cpu(u64 basemono, u64 *nextevt)
+int rcu_needs_cpu(void)
 {
-	*nextevt = KTIME_MAX;
 	return !rcu_segcblist_empty(&this_cpu_ptr(&rcu_data)->cblist) &&
 		!rcu_rdp_is_offloaded(this_cpu_ptr(&rcu_data));
 }

kernel/time/Kconfig

@@ -181,5 +181,14 @@ config HIGH_RES_TIMERS
 	  hardware is not capable then this option only increases
 	  the size of the kernel image.
 
+config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+	int "Clocksource watchdog maximum allowable skew (in μs)"
+	depends on CLOCKSOURCE_WATCHDOG
+	range 50 1000
+	default 100
+	help
+	  Specify the maximum amount of allowable watchdog skew in
+	  microseconds before reporting the clocksource to be unstable.
+
 endmenu
 endif

kernel/time/clocksource.c

@@ -107,7 +107,13 @@ static u64 suspend_start;
  * This delay could be due to SMIs, NMIs, or to VCPU preemptions.  Used as
  * a lower bound for cs->uncertainty_margin values when registering clocks.
  */
-#define WATCHDOG_MAX_SKEW (100 * NSEC_PER_USEC)
+#ifdef CONFIG_CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+#define MAX_SKEW_USEC	CONFIG_CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+#else
+#define MAX_SKEW_USEC	100
+#endif
+
+#define WATCHDOG_MAX_SKEW (MAX_SKEW_USEC * NSEC_PER_USEC)
 
 #ifdef CONFIG_CLOCKSOURCE_WATCHDOG
 static void clocksource_watchdog_work(struct work_struct *work);

kernel/time/tick-sched.c

@@ -169,6 +169,8 @@ static ktime_t tick_init_jiffy_update(void)
 	return period;
 }
 
+#define MAX_STALLED_JIFFIES 5
+
 static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now)
 {
 	int cpu = smp_processor_id();
@@ -196,6 +198,21 @@ static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now)
 	if (tick_do_timer_cpu == cpu)
 		tick_do_update_jiffies64(now);
 
+	/*
+	 * If jiffies update stalled for too long (timekeeper in stop_machine()
+	 * or VMEXIT'ed for several msecs), force an update.
+	 */
+	if (ts->last_tick_jiffies != jiffies) {
+		ts->stalled_jiffies = 0;
+		ts->last_tick_jiffies = READ_ONCE(jiffies);
+	} else {
+		if (++ts->stalled_jiffies == MAX_STALLED_JIFFIES) {
+			tick_do_update_jiffies64(now);
+			ts->stalled_jiffies = 0;
+			ts->last_tick_jiffies = READ_ONCE(jiffies);
+		}
+	}
+
 	if (ts->inidle)
 		ts->got_idle_tick = 1;
 }
@@ -768,7 +785,7 @@ static inline bool local_timer_softirq_pending(void)
 
 static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
 {
-	u64 basemono, next_tick, next_tmr, next_rcu, delta, expires;
+	u64 basemono, next_tick, delta, expires;
 	unsigned long basejiff;
 	unsigned int seq;
 
@@ -791,7 +808,7 @@ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
 	 * minimal delta which brings us back to this place
 	 * immediately. Lather, rinse and repeat...
 	 */
-	if (rcu_needs_cpu(basemono, &next_rcu) || arch_needs_cpu() ||
+	if (rcu_needs_cpu() || arch_needs_cpu() ||
 	    irq_work_needs_cpu() || local_timer_softirq_pending()) {
 		next_tick = basemono + TICK_NSEC;
 	} else {
@@ -802,10 +819,8 @@ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
 		 * disabled this also looks at the next expiring
 		 * hrtimer.
 		 */
-		next_tmr = get_next_timer_interrupt(basejiff, basemono);
-		ts->next_timer = next_tmr;
-		/* Take the next rcu event into account */
-		next_tick = next_rcu < next_tmr ? next_rcu : next_tmr;
+		next_tick = get_next_timer_interrupt(basejiff, basemono);
+		ts->next_timer = next_tick;
 	}
 
 	/*
@@ -984,6 +999,45 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
 	__tick_nohz_full_update_tick(ts, ktime_get());
 }
 
+/*
+ * A pending softirq outside an IRQ (or softirq disabled section) context
+ * should be waiting for ksoftirqd to handle it. Therefore we shouldn't
+ * reach here due to the need_resched() early check in can_stop_idle_tick().
+ *
+ * However if we are between CPUHP_AP_SMPBOOT_THREADS and CPU_TEARDOWN_CPU on the
+ * cpu_down() process, softirqs can still be raised while ksoftirqd is parked,
+ * triggering the below since wakep_softirqd() is ignored.
+ *
+ */
+static bool report_idle_softirq(void)
+{
+	static int ratelimit;
+	unsigned int pending = local_softirq_pending();
+
+	if (likely(!pending))
+		return false;
+
+	/* Some softirqs claim to be safe against hotplug and ksoftirqd parking */
+	if (!cpu_active(smp_processor_id())) {
+		pending &= ~SOFTIRQ_HOTPLUG_SAFE_MASK;
+		if (!pending)
+			return false;
+	}
+
+	if (ratelimit < 10)
+		return false;
+
+	/* On RT, softirqs handling may be waiting on some lock */
+	if (!local_bh_blocked())
+		return false;
+
+	pr_warn("NOHZ tick-stop error: local softirq work is pending, handler #%02x!!!\n",
+		pending);
+	ratelimit++;
+
+	return true;
+}
+
 static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
 {
 	/*
@@ -1010,17 +1064,8 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
 	if (need_resched())
 		return false;
 
-	if (unlikely(local_softirq_pending())) {
-		static int ratelimit;
-
-		if (ratelimit < 10 && !local_bh_blocked() &&
-		    (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
-			pr_warn("NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #%02x!!!\n",
-				(unsigned int) local_softirq_pending());
-			ratelimit++;
-		}
+	if (unlikely(report_idle_softirq()))
 		return false;
-	}
 
 	if (tick_nohz_full_enabled()) {
 		/*

kernel/time/tick-sched.h

@@ -49,6 +49,8 @@ enum tick_nohz_mode {
  * @timer_expires_base:	Base time clock monotonic for @timer_expires
  * @next_timer:		Expiry time of next expiring timer for debugging purpose only
  * @tick_dep_mask:	Tick dependency mask - is set, if someone needs the tick
+ * @last_tick_jiffies:	Value of jiffies seen on last tick
+ * @stalled_jiffies:	Number of stalled jiffies detected across ticks
  */
 struct tick_sched {
 	struct hrtimer			sched_timer;
@@ -77,6 +79,8 @@ struct tick_sched {
 	u64				next_timer;
 	ktime_t				idle_expires;
 	atomic_t			tick_dep_mask;
+	unsigned long			last_tick_jiffies;
+	unsigned int			stalled_jiffies;
 };
 
 extern struct tick_sched *tick_get_tick_sched(int cpu);