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Commit 98facf0e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 00622e61 98a01e77

Documentation/devicetree/bindings/arm/arch_timer.txt

+3 −0
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ to deliver its interrupts via SPIs. 


- 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 {

drivers/clocksource/arm_arch_timer.c

+5 −1
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ static int arch_timer_ppi[MAX_TIMER_PPI]; 
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;



/*
@@ -263,6 +264,7 @@ static void __arch_timer_setup(unsigned type, 
	clk->features = CLOCK_EVT_FEAT_ONESHOT;



	if (type == ARCH_CP15_TIMER) {

		if (arch_timer_c3stop)

			clk->features |= CLOCK_EVT_FEAT_C3STOP;

		clk->name = "arch_sys_timer";

		clk->rating = 450;
@@ -665,6 +667,8 @@ static void __init arch_timer_init(struct device_node *np) 
		}

	}



	arch_timer_c3stop = !of_property_read_bool(np, "always-on");



	arch_timer_register();

	arch_timer_common_init();

}

drivers/clocksource/zevio-timer.c

+6 −1
Original line number Diff line number Diff line
@@ -212,4 +212,9 @@ static int __init zevio_timer_add(struct device_node *node) 
	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);

kernel/hrtimer.c

+22 −0
Original line number Diff line number Diff line
@@ -234,6 +234,11 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, 
			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 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal) 


	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);

}

kernel/timer.c

+1 −1
Original line number Diff line number Diff line
@@ -838,7 +838,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires) 


	bit = find_last_bit(&mask, BITS_PER_LONG);



	mask = (1 << bit) - 1;

	mask = (1UL << bit) - 1;



	expires_limit = expires_limit & ~(mask);