From 01f8fa4f01d8362358eb90e412bd7ae18a3ec1ad Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 16 Apr 2014 14:36:44 +0000 Subject: genirq: Allow forcing cpu affinity of interrupts The current implementation of irq_set_affinity() refuses rightfully to route an interrupt to an offline cpu. But there is a special case, where this is actually desired. Some of the ARM SoCs have per cpu timers which require setting the affinity during cpu startup where the cpu is not yet in the online mask. If we can't do that, then the local timer interrupt for the about to become online cpu is routed to some random online cpu. The developers of the affected machines tried to work around that issue, but that results in a massive mess in that timer code. We have a yet unused argument in the set_affinity callbacks of the irq chips, which I added back then for a similar reason. It was never required so it got not used. But I'm happy that I never removed it. That allows us to implement a sane handling of the above scenario. So the affected SoC drivers can add the required force handling to their interrupt chip, switch the timer code to irq_force_affinity() and things just work. This does not affect any existing user of irq_set_affinity(). Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Reported-and-tested-by: Krzysztof Kozlowski Signed-off-by: Thomas Gleixner Cc: Kyungmin Park Cc: Marek Szyprowski Cc: Bartlomiej Zolnierkiewicz Cc: Tomasz Figa , Cc: Daniel Lezcano , Cc: Kukjin Kim Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de Signed-off-by: Thomas Gleixner --- arch/mips/cavium-octeon/octeon-irq.c | 2 +- include/linux/interrupt.h | 35 ++++++++++++++++++++++++++++++++++- include/linux/irq.h | 3 ++- kernel/irq/manage.c | 17 ++++++----------- 4 files changed, 43 insertions(+), 14 deletions(-) diff --git a/arch/mips/cavium-octeon/octeon-irq.c b/arch/mips/cavium-octeon/octeon-irq.c index c2bb4f896ce7..3aa5b46b2d40 100644 --- a/arch/mips/cavium-octeon/octeon-irq.c +++ b/arch/mips/cavium-octeon/octeon-irq.c @@ -635,7 +635,7 @@ static void octeon_irq_cpu_offline_ciu(struct irq_data *data) cpumask_clear(&new_affinity); cpumask_set_cpu(cpumask_first(cpu_online_mask), &new_affinity); } - __irq_set_affinity_locked(data, &new_affinity); + irq_set_affinity_locked(data, &new_affinity, false); } static int octeon_irq_ciu_set_affinity(struct irq_data *data, diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index c7bfac1c4a7b..8834a7e5b944 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -203,7 +203,40 @@ static inline int check_wakeup_irqs(void) { return 0; } extern cpumask_var_t irq_default_affinity; -extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask); +/* Internal implementation. Use the helpers below */ +extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask, + bool force); + +/** + * irq_set_affinity - Set the irq affinity of a given irq + * @irq: Interrupt to set affinity + * @mask: cpumask + * + * Fails if cpumask does not contain an online CPU + */ +static inline int +irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) +{ + return __irq_set_affinity(irq, cpumask, false); +} + +/** + * irq_force_affinity - Force the irq affinity of a given irq + * @irq: Interrupt to set affinity + * @mask: cpumask + * + * Same as irq_set_affinity, but without checking the mask against + * online cpus. + * + * Solely for low level cpu hotplug code, where we need to make per + * cpu interrupts affine before the cpu becomes online. + */ +static inline int +irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) +{ + return __irq_set_affinity(irq, cpumask, true); +} + extern int irq_can_set_affinity(unsigned int irq); extern int irq_select_affinity(unsigned int irq); diff --git a/include/linux/irq.h b/include/linux/irq.h index d278838908cb..10a0b1ac4ea0 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -394,7 +394,8 @@ extern void remove_percpu_irq(unsigned int irq, struct irqaction *act); extern void irq_cpu_online(void); extern void irq_cpu_offline(void); -extern int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *cpumask); +extern int irq_set_affinity_locked(struct irq_data *data, + const struct cpumask *cpumask, bool force); #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ) void irq_move_irq(struct irq_data *data); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 2486a4c1a710..d34131ca372b 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -180,7 +180,7 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, struct irq_chip *chip = irq_data_get_irq_chip(data); int ret; - ret = chip->irq_set_affinity(data, mask, false); + ret = chip->irq_set_affinity(data, mask, force); switch (ret) { case IRQ_SET_MASK_OK: cpumask_copy(data->affinity, mask); @@ -192,7 +192,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, return ret; } -int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask) +int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask, + bool force) { struct irq_chip *chip = irq_data_get_irq_chip(data); struct irq_desc *desc = irq_data_to_desc(data); @@ -202,7 +203,7 @@ int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask) return -EINVAL; if (irq_can_move_pcntxt(data)) { - ret = irq_do_set_affinity(data, mask, false); + ret = irq_do_set_affinity(data, mask, force); } else { irqd_set_move_pending(data); irq_copy_pending(desc, mask); @@ -217,13 +218,7 @@ int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask) return ret; } -/** - * irq_set_affinity - Set the irq affinity of a given irq - * @irq: Interrupt to set affinity - * @mask: cpumask - * - */ -int irq_set_affinity(unsigned int irq, const struct cpumask *mask) +int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force) { struct irq_desc *desc = irq_to_desc(irq); unsigned long flags; @@ -233,7 +228,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask) return -EINVAL; raw_spin_lock_irqsave(&desc->lock, flags); - ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask); + ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force); raw_spin_unlock_irqrestore(&desc->lock, flags); return ret; } -- cgit v1.2.3 From ffde1de64012c406dfdda8690918248b472f24e4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 16 Apr 2014 14:36:44 +0000 Subject: irqchip: Gic: Support forced affinity setting To support the affinity setting of per cpu timers in the early startup of a not yet online cpu, implement the force logic, which disables the cpu online check. Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Signed-off-by: Thomas Gleixner Tested-by: Krzysztof Kozlowski Cc: Kyungmin Park Cc: Marek Szyprowski Cc: Bartlomiej Zolnierkiewicz Cc: Tomasz Figa , Cc: Daniel Lezcano , Cc: Kukjin Kim Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143315.916984416@linutronix.de Signed-off-by: Thomas Gleixner --- drivers/irqchip/irq-gic.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 4300b6606f5e..57d165e026f4 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -246,10 +246,14 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val, bool force) { void __iomem *reg = gic_dist_base(d) + GIC_DIST_TARGET + (gic_irq(d) & ~3); - unsigned int shift = (gic_irq(d) % 4) * 8; - unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask); + unsigned int cpu, shift = (gic_irq(d) % 4) * 8; u32 val, mask, bit; + if (!force) + cpu = cpumask_any_and(mask_val, cpu_online_mask); + else + cpu = cpumask_first(mask_val); + if (cpu >= NR_GIC_CPU_IF || cpu >= nr_cpu_ids) return -EINVAL; -- cgit v1.2.3 From 30ccf03b4a6a2102a2219058bdc6d779dc637dd7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 16 Apr 2014 14:36:45 +0000 Subject: clocksource: Exynos_mct: Use irq_force_affinity() in cpu bringup The starting cpu is not yet in the online mask so irq_set_affinity() fails which results in per cpu timers for this cpu ending up on some other online cpu, ususally cpu 0. Use irq_force_affinity() which disables the online mask check and makes things work. Signed-off-by: Thomas Gleixner Tested-by: Krzysztof Kozlowski Cc: Kyungmin Park Cc: Marek Szyprowski Cc: Bartlomiej Zolnierkiewicz Cc: Tomasz Figa , Cc: Daniel Lezcano , Cc: Kukjin Kim Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143316.106665251@linutronix.de Signed-off-by: Thomas Gleixner --- drivers/clocksource/exynos_mct.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index a6ee6d7cd63f..b2d416368711 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -430,6 +430,7 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) evt->irq); return -EIO; } + irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); } else { enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); } @@ -450,7 +451,6 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { struct mct_clock_event_device *mevt; - unsigned int cpu; /* * Grab cpu pointer in each case to avoid spurious @@ -461,12 +461,6 @@ static int exynos4_mct_cpu_notify(struct notifier_block *self, mevt = this_cpu_ptr(&percpu_mct_tick); exynos4_local_timer_setup(&mevt->evt); break; - case CPU_ONLINE: - cpu = (unsigned long)hcpu; - if (mct_int_type == MCT_INT_SPI) - irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu], - cpumask_of(cpu)); - break; case CPU_DYING: mevt = this_cpu_ptr(&percpu_mct_tick); exynos4_local_timer_stop(&mevt->evt); -- cgit v1.2.3 From 8db6e5104b77de5d0b7002b95069da0992a34be9 Mon Sep 17 00:00:00 2001 From: Krzysztof Kozlowski Date: Wed, 16 Apr 2014 14:36:45 +0000 Subject: clocksource: Exynos_mct: Register clock event after request_irq() After hotplugging CPU1 the first call of interrupt handler for CPU1 oneshot timer was called on CPU0 because it fired before setting IRQ affinity. Affected are SoCs where Multi Core Timer interrupts are shared (SPI), e.g. Exynos 4210. During setup of the MCT timers the clock event device should be registered after setting the affinity for interrupt. This will prevent starting the timer too early. Signed-off-by: Krzysztof Kozlowski Signed-off-by: Thomas Gleixner Cc: Kyungmin Park Cc: Marek Szyprowski Cc: Bartlomiej Zolnierkiewicz Cc: Tomasz Figa , Cc: Daniel Lezcano , Cc: Kukjin Kim Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143316.299247848@linutronix.de Signed-off-by: Thomas Gleixner --- drivers/clocksource/exynos_mct.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index b2d416368711..acf5a329d538 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -416,8 +416,6 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) evt->set_mode = exynos4_tick_set_mode; evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; evt->rating = 450; - clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1), - 0xf, 0x7fffffff); exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); @@ -434,6 +432,8 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) } else { enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); } + clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1), + 0xf, 0x7fffffff); return 0; } -- cgit v1.2.3