From b525903c254dab2491410f0f23707691b7c2c317 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Thu, 31 Jan 2019 14:53:58 +0000 Subject: genirq: Provide basic NMI management for interrupt lines Add functionality to allocate interrupt lines that will deliver IRQs as Non-Maskable Interrupts. These allocations are only successful if the irqchip provides the necessary support and allows NMI delivery for the interrupt line. Interrupt lines allocated for NMI delivery must be enabled/disabled through enable_nmi/disable_nmi_nosync to keep their state consistent. To treat a PERCPU IRQ as NMI, the interrupt must not be shared nor threaded, the irqchip directly managing the IRQ must be the root irqchip and the irqchip cannot be behind a slow bus. Signed-off-by: Julien Thierry Reviewed-by: Marc Zyngier Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Marc Zyngier Signed-off-by: Marc Zyngier --- include/linux/interrupt.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index c672f34235e7..9941d1a8d83c 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -156,6 +156,10 @@ __request_percpu_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, const char *devname, void __percpu *percpu_dev_id); +extern int __must_check +request_nmi(unsigned int irq, irq_handler_t handler, unsigned long flags, + const char *name, void *dev); + static inline int __must_check request_percpu_irq(unsigned int irq, irq_handler_t handler, const char *devname, void __percpu *percpu_dev_id) @@ -167,6 +171,8 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler, extern const void *free_irq(unsigned int, void *); extern void free_percpu_irq(unsigned int, void __percpu *); +extern const void *free_nmi(unsigned int irq, void *dev_id); + struct device; extern int __must_check @@ -217,6 +223,9 @@ extern void enable_percpu_irq(unsigned int irq, unsigned int type); extern bool irq_percpu_is_enabled(unsigned int irq); extern void irq_wake_thread(unsigned int irq, void *dev_id); +extern void disable_nmi_nosync(unsigned int irq); +extern void enable_nmi(unsigned int irq); + /* The following three functions are for the core kernel use only. */ extern void suspend_device_irqs(void); extern void resume_device_irqs(void); -- cgit v1.2.3 From 4b078c3f1a26487c39363089ba0d5c6b09f2a89f Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Thu, 31 Jan 2019 14:53:59 +0000 Subject: genirq: Provide NMI management for percpu_devid interrupts Add support for percpu_devid interrupts treated as NMIs. Percpu_devid NMIs need to be setup/torn down on each CPU they target. The same restrictions as for global NMIs still apply for percpu_devid NMIs. Signed-off-by: Julien Thierry Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Marc Zyngier Signed-off-by: Marc Zyngier --- include/linux/interrupt.h | 9 +++ kernel/irq/manage.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 186 insertions(+) (limited to 'include/linux/interrupt.h') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 9941d1a8d83c..831ddcdc5597 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -168,10 +168,15 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler, devname, percpu_dev_id); } +extern int __must_check +request_percpu_nmi(unsigned int irq, irq_handler_t handler, + const char *devname, void __percpu *dev); + extern const void *free_irq(unsigned int, void *); extern void free_percpu_irq(unsigned int, void __percpu *); extern const void *free_nmi(unsigned int irq, void *dev_id); +extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id); struct device; @@ -224,7 +229,11 @@ extern bool irq_percpu_is_enabled(unsigned int irq); extern void irq_wake_thread(unsigned int irq, void *dev_id); extern void disable_nmi_nosync(unsigned int irq); +extern void disable_percpu_nmi(unsigned int irq); extern void enable_nmi(unsigned int irq); +extern void enable_percpu_nmi(unsigned int irq, unsigned int type); +extern int prepare_percpu_nmi(unsigned int irq); +extern void teardown_percpu_nmi(unsigned int irq); /* The following three functions are for the core kernel use only. */ extern void suspend_device_irqs(void); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 9472ae987946..0a1ebc004a59 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -2182,6 +2182,11 @@ out: } EXPORT_SYMBOL_GPL(enable_percpu_irq); +void enable_percpu_nmi(unsigned int irq, unsigned int type) +{ + enable_percpu_irq(irq, type); +} + /** * irq_percpu_is_enabled - Check whether the per cpu irq is enabled * @irq: Linux irq number to check for @@ -2221,6 +2226,11 @@ void disable_percpu_irq(unsigned int irq) } EXPORT_SYMBOL_GPL(disable_percpu_irq); +void disable_percpu_nmi(unsigned int irq) +{ + disable_percpu_irq(irq); +} + /* * Internal function to unregister a percpu irqaction. */ @@ -2252,6 +2262,8 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_ /* Found it - now remove it from the list of entries: */ desc->action = NULL; + desc->istate &= ~IRQS_NMI; + raw_spin_unlock_irqrestore(&desc->lock, flags); unregister_handler_proc(irq, action); @@ -2305,6 +2317,19 @@ void free_percpu_irq(unsigned int irq, void __percpu *dev_id) } EXPORT_SYMBOL_GPL(free_percpu_irq); +void free_percpu_nmi(unsigned int irq, void __percpu *dev_id) +{ + struct irq_desc *desc = irq_to_desc(irq); + + if (!desc || !irq_settings_is_per_cpu_devid(desc)) + return; + + if (WARN_ON(!(desc->istate & IRQS_NMI))) + return; + + kfree(__free_percpu_irq(irq, dev_id)); +} + /** * setup_percpu_irq - setup a per-cpu interrupt * @irq: Interrupt line to setup @@ -2394,6 +2419,158 @@ int __request_percpu_irq(unsigned int irq, irq_handler_t handler, } EXPORT_SYMBOL_GPL(__request_percpu_irq); +/** + * request_percpu_nmi - allocate a percpu interrupt line for NMI delivery + * @irq: Interrupt line to allocate + * @handler: Function to be called when the IRQ occurs. + * @name: An ascii name for the claiming device + * @dev_id: A percpu cookie passed back to the handler function + * + * This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs + * have to be setup on each CPU by calling ready_percpu_nmi() before being + * enabled on the same CPU by using enable_percpu_nmi(). + * + * Dev_id must be globally unique. It is a per-cpu variable, and + * the handler gets called with the interrupted CPU's instance of + * that variable. + * + * Interrupt lines requested for NMI delivering should have auto enabling + * setting disabled. + * + * If the interrupt line cannot be used to deliver NMIs, function + * will fail returning a negative value. + */ +int request_percpu_nmi(unsigned int irq, irq_handler_t handler, + const char *name, void __percpu *dev_id) +{ + struct irqaction *action; + struct irq_desc *desc; + unsigned long flags; + int retval; + + if (!handler) + return -EINVAL; + + desc = irq_to_desc(irq); + + if (!desc || !irq_settings_can_request(desc) || + !irq_settings_is_per_cpu_devid(desc) || + irq_settings_can_autoenable(desc) || + !irq_supports_nmi(desc)) + return -EINVAL; + + /* The line cannot already be NMI */ + if (desc->istate & IRQS_NMI) + return -EINVAL; + + action = kzalloc(sizeof(struct irqaction), GFP_KERNEL); + if (!action) + return -ENOMEM; + + action->handler = handler; + action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD + | IRQF_NOBALANCING; + action->name = name; + action->percpu_dev_id = dev_id; + + retval = irq_chip_pm_get(&desc->irq_data); + if (retval < 0) + goto err_out; + + retval = __setup_irq(irq, desc, action); + if (retval) + goto err_irq_setup; + + raw_spin_lock_irqsave(&desc->lock, flags); + desc->istate |= IRQS_NMI; + raw_spin_unlock_irqrestore(&desc->lock, flags); + + return 0; + +err_irq_setup: + irq_chip_pm_put(&desc->irq_data); +err_out: + kfree(action); + + return retval; +} + +/** + * prepare_percpu_nmi - performs CPU local setup for NMI delivery + * @irq: Interrupt line to prepare for NMI delivery + * + * This call prepares an interrupt line to deliver NMI on the current CPU, + * before that interrupt line gets enabled with enable_percpu_nmi(). + * + * As a CPU local operation, this should be called from non-preemptible + * context. + * + * If the interrupt line cannot be used to deliver NMIs, function + * will fail returning a negative value. + */ +int prepare_percpu_nmi(unsigned int irq) +{ + unsigned long flags; + struct irq_desc *desc; + int ret = 0; + + WARN_ON(preemptible()); + + desc = irq_get_desc_lock(irq, &flags, + IRQ_GET_DESC_CHECK_PERCPU); + if (!desc) + return -EINVAL; + + if (WARN(!(desc->istate & IRQS_NMI), + KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n", + irq)) { + ret = -EINVAL; + goto out; + } + + ret = irq_nmi_setup(desc); + if (ret) { + pr_err("Failed to setup NMI delivery: irq %u\n", irq); + goto out; + } + +out: + irq_put_desc_unlock(desc, flags); + return ret; +} + +/** + * teardown_percpu_nmi - undoes NMI setup of IRQ line + * @irq: Interrupt line from which CPU local NMI configuration should be + * removed + * + * This call undoes the setup done by prepare_percpu_nmi(). + * + * IRQ line should not be enabled for the current CPU. + * + * As a CPU local operation, this should be called from non-preemptible + * context. + */ +void teardown_percpu_nmi(unsigned int irq) +{ + unsigned long flags; + struct irq_desc *desc; + + WARN_ON(preemptible()); + + desc = irq_get_desc_lock(irq, &flags, + IRQ_GET_DESC_CHECK_PERCPU); + if (!desc) + return; + + if (WARN_ON(!(desc->istate & IRQS_NMI))) + goto out; + + irq_nmi_teardown(desc); +out: + irq_put_desc_unlock(desc, flags); +} + /** * irq_get_irqchip_state - returns the irqchip state of a interrupt. * @irq: Interrupt line that is forwarded to a VM -- cgit v1.2.3