From 12572dbb53638c6e454ef831c8fee7de3df24389 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 14 Jan 2013 17:05:21 +0000 Subject: [PATCH 1/4] clockevents: Add generic timer broadcast receiver Currently the broadcast mechanism used for timers is abstracted by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this ties each clock_event_device driver to a single architecture, even where the driver is otherwise generic. This patch adds a standard path for the receipt of timer broadcasts, so drivers and/or architecture backends need not manage redundant lists of timers for the purpose of routing broadcast timer ticks. [tglx: Made the implementation depend on the config switch as well ] Signed-off-by: Mark Rutland Reviewed-by: Santosh Shilimkar Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-2-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar Reviewed-by: Stephen Boyd Signed-off-by: Thomas Gleixner --- include/linux/clockchips.h | 4 ++++ kernel/time/tick-broadcast.c | 17 +++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index 8a7096fcb01e..e1089aa7816d 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -161,6 +161,10 @@ clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec) extern void clockevents_suspend(void); extern void clockevents_resume(void); +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +extern int tick_receive_broadcast(void); +#endif + #ifdef CONFIG_GENERIC_CLOCKEVENTS extern void clockevents_notify(unsigned long reason, void *arg); #else diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index f113755695e2..7cc81c57eb31 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -125,6 +125,23 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) return ret; } +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +int tick_receive_broadcast(void) +{ + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); + struct clock_event_device *evt = td->evtdev; + + if (!evt) + return -ENODEV; + + if (!evt->event_handler) + return -EINVAL; + + evt->event_handler(evt); + return 0; +} +#endif + /* * Broadcast the event to the cpus, which are set in the mask (mangled). */ From 12ad10004645d38356b14d1fbba379c523a61916 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 14 Jan 2013 17:05:22 +0000 Subject: [PATCH 2/4] clockevents: Add generic timer broadcast function Currently, the timer broadcast mechanism is defined by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this means that clock_event_device drivers cannot be shared across multiple architectures. This patch adds an (optional) architecture-specific function for timer tick broadcast, allowing drivers which may require broadcast functionality to be shared across multiple architectures. Signed-off-by: Mark Rutland Reviewed-by: Santosh Shilimkar Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-3-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar Reviewed-by: Stephen Boyd Signed-off-by: Thomas Gleixner --- include/linux/clockchips.h | 5 +++++ kernel/time/Kconfig | 4 ++++ kernel/time/tick-broadcast.c | 13 +++++++++++++ 3 files changed, 22 insertions(+) diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index e1089aa7816d..66346521cb65 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -162,6 +162,11 @@ extern void clockevents_suspend(void); extern void clockevents_resume(void); #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST +extern void tick_broadcast(const struct cpumask *mask); +#else +#define tick_broadcast NULL +#endif extern int tick_receive_broadcast(void); #endif diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 8601f0db1261..b69692250af4 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -38,6 +38,10 @@ config GENERIC_CLOCKEVENTS_BUILD default y depends on GENERIC_CLOCKEVENTS +# Architecture can handle broadcast in a driver-agnostic way +config ARCH_HAS_TICK_BROADCAST + bool + # Clockevents broadcasting infrastructure config GENERIC_CLOCKEVENTS_BROADCAST bool diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 7cc81c57eb31..f726537d24eb 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "tick-internal.h" @@ -86,6 +87,11 @@ int tick_is_broadcast_device(struct clock_event_device *dev) return (dev && tick_broadcast_device.evtdev == dev); } +static void err_broadcast(const struct cpumask *mask) +{ + pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n"); +} + /* * Check, if the device is disfunctional and a place holder, which * needs to be handled by the broadcast device. @@ -105,6 +111,13 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) */ if (!tick_device_is_functional(dev)) { dev->event_handler = tick_handle_periodic; + if (!dev->broadcast) + dev->broadcast = tick_broadcast; + if (!dev->broadcast) { + pr_warn_once("%s depends on broadcast, but no broadcast function available\n", + dev->name); + dev->broadcast = err_broadcast; + } cpumask_set_cpu(cpu, tick_get_broadcast_mask()); tick_broadcast_start_periodic(tick_broadcast_device.evtdev); ret = 1; From e2c501190c7d4bf9d7febb9e1f1094cbde59ed89 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 30 Oct 2012 11:17:01 +0000 Subject: [PATCH 3/4] arm: Use generic timer broadcast receiver Currently, the ARM backend must maintain a redundant list of timers for the purpose of centralising timer broadcast functionality. This prevents sharing timer drivers across architectures. This patch moves the pain of dealing with timer broadcasts to the core clockevents tick broadcast code, which already maintains its own list of timers. Signed-off-by: Mark Rutland Reviewed-by: Santosh Shilimkar Tested-by: Santosh Shilimkar Reviewed-by: Stephen Boyd --- arch/arm/kernel/smp.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 84f4cbf652e5..930851912b37 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -475,12 +475,6 @@ u64 smp_irq_stat_cpu(unsigned int cpu) */ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); -static void ipi_timer(void) -{ - struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent); - evt->event_handler(evt); -} - #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST static void smp_timer_broadcast(const struct cpumask *mask) { @@ -596,11 +590,13 @@ void handle_IPI(int ipinr, struct pt_regs *regs) case IPI_WAKEUP: break; +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST case IPI_TIMER: irq_enter(); - ipi_timer(); + tick_receive_broadcast(); irq_exit(); break; +#endif case IPI_RESCHEDULE: scheduler_ipi(); From 3d06770eef43eaad606e77246bfcc7e82b1d9fb4 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 30 Oct 2012 12:13:42 +0000 Subject: [PATCH 4/4] arm: Add generic timer broadcast support Implement timer_broadcast for the arm architecture, allowing for the use of clock_event_device_drivers decoupled from the timer tick broadcast mechanism. Signed-off-by: Mark Rutland Reviewed-by: Santosh Shilimkar Tested-by: Santosh Shilimkar Reviewed-by: Stephen Boyd --- arch/arm/Kconfig | 1 + arch/arm/kernel/smp.c | 3 +-- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 67874b82a4ed..65ae7375c6c1 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -4,6 +4,7 @@ config ARM select ARCH_BINFMT_ELF_RANDOMIZE_PIE select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAVE_CUSTOM_GPIO_H + select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_WANT_IPC_PARSE_VERSION select BUILDTIME_EXTABLE_SORT if MMU select CPU_PM if (SUSPEND || CPU_IDLE) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 930851912b37..b7e3b506219b 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -476,7 +476,7 @@ u64 smp_irq_stat_cpu(unsigned int cpu) static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST -static void smp_timer_broadcast(const struct cpumask *mask) +void tick_broadcast(const struct cpumask *mask) { smp_cross_call(mask, IPI_TIMER); } @@ -524,7 +524,6 @@ static void __cpuinit percpu_timer_setup(void) struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); evt->cpumask = cpumask_of(cpu); - evt->broadcast = smp_timer_broadcast; if (!lt_ops || lt_ops->setup(evt)) broadcast_timer_setup(evt);