Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
"This update brings along:
- Two fixes for long standing bugs in the hrtimer code, one which
prevents remote enqueuing and the other preventing arbitrary delays
after a interrupt hang was detected
- A fix in the timer wheel which prevents math overflow
- A fix for a long standing issue with the architected ARM timer
related to the C3STOP mechanism.
- A trivial compile fix for nspire SoC clocksource"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timer: Prevent overflow in apply_slack
hrtimer: Prevent remote enqueue of leftmost timers
hrtimer: Prevent all reprogramming if hang detected
clocksource: nspire: Fix compiler warning
clocksource: arch_arm_timer: Fix age-old arch timer C3STOP detection issue
diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index 06fc760..37b2caf 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -19,6 +19,9 @@
- clock-frequency : The frequency of the main counter, in Hz. Optional.
+- always-on : a boolean property. If present, the timer is powered through an
+ always-on power domain, therefore it never loses context.
+
Example:
timer {
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 57e823c..5163ec1 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -66,6 +66,7 @@
static struct clock_event_device __percpu *arch_timer_evt;
static bool arch_timer_use_virtual = true;
+static bool arch_timer_c3stop;
static bool arch_timer_mem_use_virtual;
/*
@@ -263,7 +264,8 @@
clk->features = CLOCK_EVT_FEAT_ONESHOT;
if (type == ARCH_CP15_TIMER) {
- clk->features |= CLOCK_EVT_FEAT_C3STOP;
+ if (arch_timer_c3stop)
+ clk->features |= CLOCK_EVT_FEAT_C3STOP;
clk->name = "arch_sys_timer";
clk->rating = 450;
clk->cpumask = cpumask_of(smp_processor_id());
@@ -665,6 +667,8 @@
}
}
+ arch_timer_c3stop = !of_property_read_bool(np, "always-on");
+
arch_timer_register();
arch_timer_common_init();
}
diff --git a/drivers/clocksource/zevio-timer.c b/drivers/clocksource/zevio-timer.c
index ca81809..7ce4421 100644
--- a/drivers/clocksource/zevio-timer.c
+++ b/drivers/clocksource/zevio-timer.c
@@ -212,4 +212,9 @@
return ret;
}
-CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_add);
+static void __init zevio_timer_init(struct device_node *node)
+{
+ BUG_ON(zevio_timer_add(node));
+}
+
+CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init);
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index d55092c..6b715c0 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -234,6 +234,11 @@
goto again;
}
timer->base = new_base;
+ } else {
+ if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
+ cpu = this_cpu;
+ goto again;
+ }
}
return new_base;
}
@@ -569,6 +574,23 @@
cpu_base->expires_next.tv64 = expires_next.tv64;
+ /*
+ * If a hang was detected in the last timer interrupt then we
+ * leave the hang delay active in the hardware. We want the
+ * system to make progress. That also prevents the following
+ * scenario:
+ * T1 expires 50ms from now
+ * T2 expires 5s from now
+ *
+ * T1 is removed, so this code is called and would reprogram
+ * the hardware to 5s from now. Any hrtimer_start after that
+ * will not reprogram the hardware due to hang_detected being
+ * set. So we'd effectivly block all timers until the T2 event
+ * fires.
+ */
+ if (cpu_base->hang_detected)
+ return;
+
if (cpu_base->expires_next.tv64 != KTIME_MAX)
tick_program_event(cpu_base->expires_next, 1);
}
diff --git a/kernel/timer.c b/kernel/timer.c
index 87bd529..3bb01a3 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -838,7 +838,7 @@
bit = find_last_bit(&mask, BITS_PER_LONG);
- mask = (1 << bit) - 1;
+ mask = (1UL << bit) - 1;
expires_limit = expires_limit & ~(mask);
