[GIT pull] timer updates for 3.11

From: Thomas Gleixner
Date: Sat Jul 13 2013 - 07:13:22 EST

Linus,

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

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

* Watchdog fixes for full dynticks
* Improved debug output for full dynticks
* Remove an obsolete full dynticks check
* Two ARM SoC clocksource drivers for sharing across SoCs
* Tick broadcast fix for CPU hotplug

Thanks,

tglx

------------------>
Frederic Weisbecker (4):
watchdog: Register / unregister watchdog kthreads on sysctl control
watchdog: Rename confusing state variable
watchdog: Boot-disable by default on full dynticks
nohz: Remove obsolete check for full dynticks CPUs to be RCU nocbs

Sebastian Hesselbarth (1):
clocksource: Add Marvell Orion SoC timer

Stephen Boyd (1):
tick: broadcast: Check broadcast mode on CPU hotplug

Steven Rostedt (1):
nohz: Warn if the machine can not perform nohz_full

Stuart Menefy (1):
clocksource: arm_global_timer: Add ARM global timer support


.../devicetree/bindings/arm/global_timer.txt | 24 ++
.../bindings/timer/marvell,orion-timer.txt | 17 ++
drivers/clocksource/Kconfig | 18 ++
drivers/clocksource/Makefile | 2 +
drivers/clocksource/arm_global_timer.c | 321 ++++++++++++++++++++
drivers/clocksource/time-orion.c | 150 +++++++++
include/linux/nmi.h | 2 +-
kernel/sysctl.c | 4 +-
kernel/time/tick-broadcast.c | 5 +-
kernel/time/tick-sched.c | 15 +-
kernel/watchdog.c | 113 ++++---
11 files changed, 608 insertions(+), 63 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/global_timer.txt
create mode 100644 Documentation/devicetree/bindings/timer/marvell,orion-timer.txt
create mode 100644 drivers/clocksource/arm_global_timer.c
create mode 100644 drivers/clocksource/time-orion.c

diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
new file mode 100644
index 0000000..1e54898
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/global_timer.txt
@@ -0,0 +1,24 @@
+
+* ARM Global Timer
+ Cortex-A9 are often associated with a per-core Global timer.
+
+** Timer node required properties:
+
+- compatible : Should be "arm,cortex-a9-global-timer"
+ Driver supports versions r2p0 and above.
+
+- interrupts : One interrupt to each core
+
+- reg : Specify the base address and the size of the GT timer
+ register window.
+
+- clocks : Should be phandle to a clock.
+
+Example:
+
+ timer@2c000600 {
+ compatible = "arm,cortex-a9-global-timer";
+ reg = <0x2c000600 0x20>;
+ interrupts = <1 13 0xf01>;
+ clocks = <&arm_periph_clk>;
+ };
diff --git a/Documentation/devicetree/bindings/timer/marvell,orion-timer.txt b/Documentation/devicetree/bindings/timer/marvell,orion-timer.txt
new file mode 100644
index 0000000..62bb826
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/marvell,orion-timer.txt
@@ -0,0 +1,17 @@
+Marvell Orion SoC timer
+
+Required properties:
+- compatible: shall be "marvell,orion-timer"
+- reg: base address of the timer register starting with TIMERS CONTROL register
+- interrupt-parent: phandle of the bridge interrupt controller
+- interrupts: should contain the interrupts for Timer0 and Timer1
+- clocks: phandle of timer reference clock (tclk)
+
+Example:
+ timer: timer {
+ compatible = "marvell,orion-timer";
+ reg = <0x20300 0x20>;
+ interrupt-parent = <&bridge_intc>;
+ interrupts = <1>, <2>;
+ clocks = <&core_clk 0>;
+ };
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 81465c2..b7b9b04 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -27,6 +27,11 @@ config DW_APB_TIMER_OF
config ARMADA_370_XP_TIMER
bool

+config ORION_TIMER
+ select CLKSRC_OF
+ select CLKSRC_MMIO
+ bool
+
config SUN4I_TIMER
bool

@@ -69,6 +74,19 @@ config ARM_ARCH_TIMER
bool
select CLKSRC_OF if OF

+config ARM_GLOBAL_TIMER
+ bool
+ select CLKSRC_OF if OF
+ help
+ This options enables support for the ARM global timer unit
+
+config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+ bool
+ depends on ARM_GLOBAL_TIMER
+ default y
+ help
+ Use ARM global timer clock source as sched_clock
+
config CLKSRC_METAG_GENERIC
def_bool y if METAG
help
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 9ba8b4d..8b00c5c 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_DW_APB_TIMER_OF) += dw_apb_timer_of.o
obj-$(CONFIG_CLKSRC_NOMADIK_MTU) += nomadik-mtu.o
obj-$(CONFIG_CLKSRC_DBX500_PRCMU) += clksrc-dbx500-prcmu.o
obj-$(CONFIG_ARMADA_370_XP_TIMER) += time-armada-370-xp.o
+obj-$(CONFIG_ORION_TIMER) += time-orion.o
obj-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o
obj-$(CONFIG_ARCH_MARCO) += timer-marco.o
obj-$(CONFIG_ARCH_MXS) += mxs_timer.o
@@ -30,5 +31,6 @@ obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o
obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o

obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
+obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o
obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
new file mode 100644
index 0000000..db8afc7
--- /dev/null
+++ b/drivers/clocksource/arm_global_timer.c
@@ -0,0 +1,321 @@
+/*
+ * drivers/clocksource/arm_global_timer.c
+ *
+ * Copyright (C) 2013 STMicroelectronics (R&D) Limited.
+ * Author: Stuart Menefy <stuart.menefy@xxxxxx>
+ * Author: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/sched_clock.h>
+
+#include <asm/cputype.h>
+
+#define GT_COUNTER0 0x00
+#define GT_COUNTER1 0x04
+
+#define GT_CONTROL 0x08
+#define GT_CONTROL_TIMER_ENABLE BIT(0) /* this bit is NOT banked */
+#define GT_CONTROL_COMP_ENABLE BIT(1) /* banked */
+#define GT_CONTROL_IRQ_ENABLE BIT(2) /* banked */
+#define GT_CONTROL_AUTO_INC BIT(3) /* banked */
+
+#define GT_INT_STATUS 0x0c
+#define GT_INT_STATUS_EVENT_FLAG BIT(0)
+
+#define GT_COMP0 0x10
+#define GT_COMP1 0x14
+#define GT_AUTO_INC 0x18
+
+/*
+ * We are expecting to be clocked by the ARM peripheral clock.
+ *
+ * Note: it is assumed we are using a prescaler value of zero, so this is
+ * the units for all operations.
+ */
+static void __iomem *gt_base;
+static unsigned long gt_clk_rate;
+static int gt_ppi;
+static struct clock_event_device __percpu *gt_evt;
+
+/*
+ * To get the value from the Global Timer Counter register proceed as follows:
+ * 1. Read the upper 32-bit timer counter register
+ * 2. Read the lower 32-bit timer counter register
+ * 3. Read the upper 32-bit timer counter register again. If the value is
+ * different to the 32-bit upper value read previously, go back to step 2.
+ * Otherwise the 64-bit timer counter value is correct.
+ */
+static u64 gt_counter_read(void)
+{
+ u64 counter;
+ u32 lower;
+ u32 upper, old_upper;
+
+ upper = readl_relaxed(gt_base + GT_COUNTER1);
+ do {
+ old_upper = upper;
+ lower = readl_relaxed(gt_base + GT_COUNTER0);
+ upper = readl_relaxed(gt_base + GT_COUNTER1);
+ } while (upper != old_upper);
+
+ counter = upper;
+ counter <<= 32;
+ counter |= lower;
+ return counter;
+}
+
+/**
+ * To ensure that updates to comparator value register do not set the
+ * Interrupt Status Register proceed as follows:
+ * 1. Clear the Comp Enable bit in the Timer Control Register.
+ * 2. Write the lower 32-bit Comparator Value Register.
+ * 3. Write the upper 32-bit Comparator Value Register.
+ * 4. Set the Comp Enable bit and, if necessary, the IRQ enable bit.
+ */
+static void gt_compare_set(unsigned long delta, int periodic)
+{
+ u64 counter = gt_counter_read();
+ unsigned long ctrl;
+
+ counter += delta;
+ ctrl = GT_CONTROL_TIMER_ENABLE;
+ writel(ctrl, gt_base + GT_CONTROL);
+ writel(lower_32_bits(counter), gt_base + GT_COMP0);
+ writel(upper_32_bits(counter), gt_base + GT_COMP1);
+
+ if (periodic) {
+ writel(delta, gt_base + GT_AUTO_INC);
+ ctrl |= GT_CONTROL_AUTO_INC;
+ }
+
+ ctrl |= GT_CONTROL_COMP_ENABLE | GT_CONTROL_IRQ_ENABLE;
+ writel(ctrl, gt_base + GT_CONTROL);
+}
+
+static void gt_clockevent_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ unsigned long ctrl;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ gt_compare_set(DIV_ROUND_CLOSEST(gt_clk_rate, HZ), 1);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ ctrl = readl(gt_base + GT_CONTROL);
+ ctrl &= ~(GT_CONTROL_COMP_ENABLE |
+ GT_CONTROL_IRQ_ENABLE | GT_CONTROL_AUTO_INC);
+ writel(ctrl, gt_base + GT_CONTROL);
+ break;
+ default:
+ break;
+ }
+}
+
+static int gt_clockevent_set_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ gt_compare_set(evt, 0);
+ return 0;
+}
+
+static irqreturn_t gt_clockevent_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ if (!(readl_relaxed(gt_base + GT_INT_STATUS) &
+ GT_INT_STATUS_EVENT_FLAG))
+ return IRQ_NONE;
+
+ /**
+ * ERRATA 740657( Global Timer can send 2 interrupts for
+ * the same event in single-shot mode)
+ * Workaround:
+ * Either disable single-shot mode.
+ * Or
+ * Modify the Interrupt Handler to avoid the
+ * offending sequence. This is achieved by clearing
+ * the Global Timer flag _after_ having incremented
+ * the Comparator register value to a higher value.
+ */
+ if (evt->mode == CLOCK_EVT_MODE_ONESHOT)
+ gt_compare_set(ULONG_MAX, 0);
+
+ writel_relaxed(GT_INT_STATUS_EVENT_FLAG, gt_base + GT_INT_STATUS);
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int __cpuinit gt_clockevents_init(struct clock_event_device *clk)
+{
+ int cpu = smp_processor_id();
+
+ clk->name = "arm_global_timer";
+ clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ clk->set_mode = gt_clockevent_set_mode;
+ clk->set_next_event = gt_clockevent_set_next_event;
+ clk->cpumask = cpumask_of(cpu);
+ clk->rating = 300;
+ clk->irq = gt_ppi;
+ clockevents_config_and_register(clk, gt_clk_rate,
+ 1, 0xffffffff);
+ enable_percpu_irq(clk->irq, IRQ_TYPE_NONE);
+ return 0;
+}
+
+static void gt_clockevents_stop(struct clock_event_device *clk)
+{
+ gt_clockevent_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
+ disable_percpu_irq(clk->irq);
+}
+
+static cycle_t gt_clocksource_read(struct clocksource *cs)
+{
+ return gt_counter_read();
+}
+
+static struct clocksource gt_clocksource = {
+ .name = "arm_global_timer",
+ .rating = 300,
+ .read = gt_clocksource_read,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+#ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+static u32 notrace gt_sched_clock_read(void)
+{
+ return gt_counter_read();
+}
+#endif
+
+static void __init gt_clocksource_init(void)
+{
+ writel(0, gt_base + GT_CONTROL);
+ writel(0, gt_base + GT_COUNTER0);
+ writel(0, gt_base + GT_COUNTER1);
+ /* enables timer on all the cores */
+ writel(GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL);
+
+#ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+ setup_sched_clock(gt_sched_clock_read, 32, gt_clk_rate);
+#endif
+ clocksource_register_hz(&gt_clocksource, gt_clk_rate);
+}
+
+static int __cpuinit gt_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ gt_clockevents_init(this_cpu_ptr(gt_evt));
+ break;
+ case CPU_DYING:
+ gt_clockevents_stop(this_cpu_ptr(gt_evt));
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+static struct notifier_block gt_cpu_nb __cpuinitdata = {
+ .notifier_call = gt_cpu_notify,
+};
+
+static void __init global_timer_of_register(struct device_node *np)
+{
+ struct clk *gt_clk;
+ int err = 0;
+
+ /*
+ * In r2p0 the comparators for each processor with the global timer
+ * fire when the timer value is greater than or equal to. In previous
+ * revisions the comparators fired when the timer value was equal to.
+ */
+ if ((read_cpuid_id() & 0xf0000f) < 0x200000) {
+ pr_warn("global-timer: non support for this cpu version.\n");
+ return;
+ }
+
+ gt_ppi = irq_of_parse_and_map(np, 0);
+ if (!gt_ppi) {
+ pr_warn("global-timer: unable to parse irq\n");
+ return;
+ }
+
+ gt_base = of_iomap(np, 0);
+ if (!gt_base) {
+ pr_warn("global-timer: invalid base address\n");
+ return;
+ }
+
+ gt_clk = of_clk_get(np, 0);
+ if (!IS_ERR(gt_clk)) {
+ err = clk_prepare_enable(gt_clk);
+ if (err)
+ goto out_unmap;
+ } else {
+ pr_warn("global-timer: clk not found\n");
+ err = -EINVAL;
+ goto out_unmap;
+ }
+
+ gt_clk_rate = clk_get_rate(gt_clk);
+ gt_evt = alloc_percpu(struct clock_event_device);
+ if (!gt_evt) {
+ pr_warn("global-timer: can't allocate memory\n");
+ err = -ENOMEM;
+ goto out_clk;
+ }
+
+ err = request_percpu_irq(gt_ppi, gt_clockevent_interrupt,
+ "gt", gt_evt);
+ if (err) {
+ pr_warn("global-timer: can't register interrupt %d (%d)\n",
+ gt_ppi, err);
+ goto out_free;
+ }
+
+ err = register_cpu_notifier(&gt_cpu_nb);
+ if (err) {
+ pr_warn("global-timer: unable to register cpu notifier.\n");
+ goto out_irq;
+ }
+
+ /* Immediately configure the timer on the boot CPU */
+ gt_clocksource_init();
+ gt_clockevents_init(this_cpu_ptr(gt_evt));
+
+ return;
+
+out_irq:
+ free_percpu_irq(gt_ppi, gt_evt);
+out_free:
+ free_percpu(gt_evt);
+out_clk:
+ clk_disable_unprepare(gt_clk);
+out_unmap:
+ iounmap(gt_base);
+ WARN(err, "ARM Global timer register failed (%d)\n", err);
+}
+
+/* Only tested on r2p2 and r3p0 */
+CLOCKSOURCE_OF_DECLARE(arm_gt, "arm,cortex-a9-global-timer",
+ global_timer_of_register);
diff --git a/drivers/clocksource/time-orion.c b/drivers/clocksource/time-orion.c
new file mode 100644
index 0000000..ecbeb68
--- /dev/null
+++ b/drivers/clocksource/time-orion.c
@@ -0,0 +1,150 @@
+/*
+ * Marvell Orion SoC timer handling.
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * Timer 0 is used as free-running clocksource, while timer 1 is
+ * used as clock_event_device.
+ */
+
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/spinlock.h>
+#include <asm/sched_clock.h>
+
+#define TIMER_CTRL 0x00
+#define TIMER0_EN BIT(0)
+#define TIMER0_RELOAD_EN BIT(1)
+#define TIMER1_EN BIT(2)
+#define TIMER1_RELOAD_EN BIT(3)
+#define TIMER0_RELOAD 0x10
+#define TIMER0_VAL 0x14
+#define TIMER1_RELOAD 0x18
+#define TIMER1_VAL 0x1c
+
+#define ORION_ONESHOT_MIN 1
+#define ORION_ONESHOT_MAX 0xfffffffe
+
+static void __iomem *timer_base;
+static DEFINE_SPINLOCK(timer_ctrl_lock);
+
+/*
+ * Thread-safe access to TIMER_CTRL register
+ * (shared with watchdog timer)
+ */
+void orion_timer_ctrl_clrset(u32 clr, u32 set)
+{
+ spin_lock(&timer_ctrl_lock);
+ writel((readl(timer_base + TIMER_CTRL) & ~clr) | set,
+ timer_base + TIMER_CTRL);
+ spin_unlock(&timer_ctrl_lock);
+}
+EXPORT_SYMBOL(orion_timer_ctrl_clrset);
+
+/*
+ * Free-running clocksource handling.
+ */
+static u32 notrace orion_read_sched_clock(void)
+{
+ return ~readl(timer_base + TIMER0_VAL);
+}
+
+/*
+ * Clockevent handling.
+ */
+static u32 ticks_per_jiffy;
+
+static int orion_clkevt_next_event(unsigned long delta,
+ struct clock_event_device *dev)
+{
+ /* setup and enable one-shot timer */
+ writel(delta, timer_base + TIMER1_VAL);
+ orion_timer_ctrl_clrset(TIMER1_RELOAD_EN, TIMER1_EN);
+
+ return 0;
+}
+
+static void orion_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev)
+{
+ if (mode == CLOCK_EVT_MODE_PERIODIC) {
+ /* setup and enable periodic timer at 1/HZ intervals */
+ writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
+ writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
+ orion_timer_ctrl_clrset(0, TIMER1_RELOAD_EN | TIMER1_EN);
+ } else {
+ /* disable timer */
+ orion_timer_ctrl_clrset(TIMER1_RELOAD_EN | TIMER1_EN, 0);
+ }
+}
+
+static struct clock_event_device orion_clkevt = {
+ .name = "orion_event",
+ .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
+ .shift = 32,
+ .rating = 300,
+ .set_next_event = orion_clkevt_next_event,
+ .set_mode = orion_clkevt_mode,
+};
+
+static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id)
+{
+ orion_clkevt.event_handler(&orion_clkevt);
+ return IRQ_HANDLED;
+}
+
+static struct irqaction orion_clkevt_irq = {
+ .name = "orion_event",
+ .flags = IRQF_TIMER,
+ .handler = orion_clkevt_irq_handler,
+};
+
+static void __init orion_timer_init(struct device_node *np)
+{
+ struct clk *clk;
+ int irq;
+
+ /* timer registers are shared with watchdog timer */
+ timer_base = of_iomap(np, 0);
+ if (!timer_base)
+ panic("%s: unable to map resource\n", np->name);
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk))
+ panic("%s: unable to get clk\n", np->name);
+ clk_prepare_enable(clk);
+
+ /* we are only interested in timer1 irq */
+ irq = irq_of_parse_and_map(np, 1);
+ if (irq <= 0)
+ panic("%s: unable to parse timer1 irq\n", np->name);
+
+ /* setup timer0 as free-running clocksource */
+ writel(~0, timer_base + TIMER0_VAL);
+ writel(~0, timer_base + TIMER0_RELOAD);
+ orion_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | TIMER0_EN);
+ clocksource_mmio_init(timer_base + TIMER0_VAL, "orion_clocksource",
+ clk_get_rate(clk), 300, 32,
+ clocksource_mmio_readl_down);
+ setup_sched_clock(orion_read_sched_clock, 32, clk_get_rate(clk));
+
+ /* setup timer1 as clockevent timer */
+ if (setup_irq(irq, &orion_clkevt_irq))
+ panic("%s: unable to setup irq\n", np->name);
+
+ ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ;
+ orion_clkevt.cpumask = cpumask_of(0);
+ orion_clkevt.irq = irq;
+ clockevents_config_and_register(&orion_clkevt, clk_get_rate(clk),
+ ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
+}
+CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index db50840..6a45fb5 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -46,7 +46,7 @@ static inline bool trigger_all_cpu_backtrace(void)
#ifdef CONFIG_LOCKUP_DETECTOR
int hw_nmi_is_cpu_stuck(struct pt_regs *);
u64 hw_nmi_get_sample_period(int watchdog_thresh);
-extern int watchdog_enabled;
+extern int watchdog_user_enabled;
extern int watchdog_thresh;
struct ctl_table;
extern int proc_dowatchdog(struct ctl_table *, int ,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e5b31af..ac09d98 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -807,7 +807,7 @@ static struct ctl_table kern_table[] = {
#if defined(CONFIG_LOCKUP_DETECTOR)
{
.procname = "watchdog",
- .data = &watchdog_enabled,
+ .data = &watchdog_user_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dowatchdog,
@@ -834,7 +834,7 @@ static struct ctl_table kern_table[] = {
},
{
.procname = "nmi_watchdog",
- .data = &watchdog_enabled,
+ .data = &watchdog_user_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dowatchdog,
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 6d3f916..218bcb5 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -157,7 +157,10 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
dev->event_handler = tick_handle_periodic;
tick_device_setup_broadcast_func(dev);
cpumask_set_cpu(cpu, tick_broadcast_mask);
- tick_broadcast_start_periodic(bc);
+ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+ tick_broadcast_start_periodic(bc);
+ else
+ tick_broadcast_setup_oneshot(bc);
ret = 1;
} else {
/*
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 0cf1c14..6960172 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -178,6 +178,11 @@ static bool can_stop_full_tick(void)
*/
if (!sched_clock_stable) {
trace_tick_stop(0, "unstable sched clock\n");
+ /*
+ * Don't allow the user to think they can get
+ * full NO_HZ with this machine.
+ */
+ WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock");
return false;
}
#endif
@@ -346,16 +351,6 @@ void __init tick_nohz_init(void)
}

cpu_notifier(tick_nohz_cpu_down_callback, 0);
-
- /* Make sure full dynticks CPU are also RCU nocbs */
- for_each_cpu(cpu, nohz_full_mask) {
- if (!rcu_is_nocb_cpu(cpu)) {
- pr_warning("NO_HZ: CPU %d is not RCU nocb: "
- "cleared from nohz_full range", cpu);
- cpumask_clear_cpu(cpu, nohz_full_mask);
- }
- }
-
cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), nohz_full_mask);
pr_info("NO_HZ: Full dynticks CPUs: %s.\n", nohz_full_buf);
}
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 05039e3..1241d8c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -29,9 +29,9 @@
#include <linux/kvm_para.h>
#include <linux/perf_event.h>

-int watchdog_enabled = 1;
+int watchdog_user_enabled = 1;
int __read_mostly watchdog_thresh = 10;
-static int __read_mostly watchdog_disabled;
+static int __read_mostly watchdog_running;
static u64 __read_mostly sample_period;

static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -63,7 +63,7 @@ static int __init hardlockup_panic_setup(char *str)
else if (!strncmp(str, "nopanic", 7))
hardlockup_panic = 0;
else if (!strncmp(str, "0", 1))
- watchdog_enabled = 0;
+ watchdog_user_enabled = 0;
return 1;
}
__setup("nmi_watchdog=", hardlockup_panic_setup);
@@ -82,7 +82,7 @@ __setup("softlockup_panic=", softlockup_panic_setup);

static int __init nowatchdog_setup(char *str)
{
- watchdog_enabled = 0;
+ watchdog_user_enabled = 0;
return 1;
}
__setup("nowatchdog", nowatchdog_setup);
@@ -90,7 +90,7 @@ __setup("nowatchdog", nowatchdog_setup);
/* deprecated */
static int __init nosoftlockup_setup(char *str)
{
- watchdog_enabled = 0;
+ watchdog_user_enabled = 0;
return 1;
}
__setup("nosoftlockup", nosoftlockup_setup);
@@ -158,7 +158,7 @@ void touch_all_softlockup_watchdogs(void)
#ifdef CONFIG_HARDLOCKUP_DETECTOR
void touch_nmi_watchdog(void)
{
- if (watchdog_enabled) {
+ if (watchdog_user_enabled) {
unsigned cpu;

for_each_present_cpu(cpu) {
@@ -347,11 +347,6 @@ static void watchdog_enable(unsigned int cpu)
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = watchdog_timer_fn;

- if (!watchdog_enabled) {
- kthread_park(current);
- return;
- }
-
/* Enable the perf event */
watchdog_nmi_enable(cpu);

@@ -374,6 +369,11 @@ static void watchdog_disable(unsigned int cpu)
watchdog_nmi_disable(cpu);
}

+static void watchdog_cleanup(unsigned int cpu, bool online)
+{
+ watchdog_disable(cpu);
+}
+
static int watchdog_should_run(unsigned int cpu)
{
return __this_cpu_read(hrtimer_interrupts) !=
@@ -475,28 +475,40 @@ static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
static void watchdog_nmi_disable(unsigned int cpu) { return; }
#endif /* CONFIG_HARDLOCKUP_DETECTOR */

-/* prepare/enable/disable routines */
-/* sysctl functions */
-#ifdef CONFIG_SYSCTL
-static void watchdog_enable_all_cpus(void)
+static struct smp_hotplug_thread watchdog_threads = {
+ .store = &softlockup_watchdog,
+ .thread_should_run = watchdog_should_run,
+ .thread_fn = watchdog,
+ .thread_comm = "watchdog/%u",
+ .setup = watchdog_enable,
+ .cleanup = watchdog_cleanup,
+ .park = watchdog_disable,
+ .unpark = watchdog_enable,
+};
+
+static int watchdog_enable_all_cpus(void)
{
- unsigned int cpu;
+ int err = 0;

- if (watchdog_disabled) {
- watchdog_disabled = 0;
- for_each_online_cpu(cpu)
- kthread_unpark(per_cpu(softlockup_watchdog, cpu));
+ if (!watchdog_running) {
+ err = smpboot_register_percpu_thread(&watchdog_threads);
+ if (err)
+ pr_err("Failed to create watchdog threads, disabled\n");
+ else
+ watchdog_running = 1;
}
+
+ return err;
}

+/* prepare/enable/disable routines */
+/* sysctl functions */
+#ifdef CONFIG_SYSCTL
static void watchdog_disable_all_cpus(void)
{
- unsigned int cpu;
-
- if (!watchdog_disabled) {
- watchdog_disabled = 1;
- for_each_online_cpu(cpu)
- kthread_park(per_cpu(softlockup_watchdog, cpu));
+ if (watchdog_running) {
+ watchdog_running = 0;
+ smpboot_unregister_percpu_thread(&watchdog_threads);
}
}

@@ -507,45 +519,48 @@ static void watchdog_disable_all_cpus(void)
int proc_dowatchdog(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- int ret;
+ int err, old_thresh, old_enabled;

- if (watchdog_disabled < 0)
- return -ENODEV;
+ old_thresh = ACCESS_ONCE(watchdog_thresh);
+ old_enabled = ACCESS_ONCE(watchdog_user_enabled);

- ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
- if (ret || !write)
- return ret;
+ err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ if (err || !write)
+ return err;

set_sample_period();
/*
* Watchdog threads shouldn't be enabled if they are
- * disabled. The 'watchdog_disabled' variable check in
+ * disabled. The 'watchdog_running' variable check in
* watchdog_*_all_cpus() function takes care of this.
*/
- if (watchdog_enabled && watchdog_thresh)
- watchdog_enable_all_cpus();
+ if (watchdog_user_enabled && watchdog_thresh)
+ err = watchdog_enable_all_cpus();
else
watchdog_disable_all_cpus();

- return ret;
+ /* Restore old values on failure */
+ if (err) {
+ watchdog_thresh = old_thresh;
+ watchdog_user_enabled = old_enabled;
+ }
+
+ return err;
}
#endif /* CONFIG_SYSCTL */

-static struct smp_hotplug_thread watchdog_threads = {
- .store = &softlockup_watchdog,
- .thread_should_run = watchdog_should_run,
- .thread_fn = watchdog,
- .thread_comm = "watchdog/%u",
- .setup = watchdog_enable,
- .park = watchdog_disable,
- .unpark = watchdog_enable,
-};
-
void __init lockup_detector_init(void)
{
set_sample_period();
- if (smpboot_register_percpu_thread(&watchdog_threads)) {
- pr_err("Failed to create watchdog threads, disabled\n");
- watchdog_disabled = -ENODEV;
+
+#ifdef CONFIG_NO_HZ_FULL
+ if (watchdog_user_enabled) {
+ watchdog_user_enabled = 0;
+ pr_warning("Disabled lockup detectors by default for full dynticks\n");
+ pr_warning("You can reactivate it with 'sysctl -w kernel.watchdog=1'\n");
}
+#endif
+
+ if (watchdog_user_enabled)
+ watchdog_enable_all_cpus();
}
--
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