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a899418167
When a cpu goes up some architectures (e.g. x86) have to walk the irq space to set up the vector space for the cpu. While this needs extra protection at the architecture level we can avoid a few race conditions by preventing the concurrent allocation/free of irq descriptors and the associated data. When a cpu goes down it moves the interrupts which are targeted to this cpu away by reassigning the affinities. While this happens interrupts can be allocated and freed, which opens a can of race conditions in the code which reassignes the affinities because interrupt descriptors might be freed underneath. Example: CPU1 CPU2 cpu_up/down irq_desc = irq_to_desc(irq); remove_from_radix_tree(desc); raw_spin_lock(&desc->lock); free(desc); We could protect the irq descriptors with RCU, but that would require a full tree change of all accesses to interrupt descriptors. But fortunately these kind of race conditions are rather limited to a few things like cpu hotplug. The normal setup/teardown is very well serialized. So the simpler and obvious solution is: Prevent allocation and freeing of interrupt descriptors accross cpu hotplug. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: xiao jin <jin.xiao@intel.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Borislav Petkov <bp@suse.de> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Link: http://lkml.kernel.org/r/20150705171102.063519515@linutronix.de
276 lines
8.1 KiB
C
276 lines
8.1 KiB
C
#ifndef _LINUX_IRQDESC_H
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#define _LINUX_IRQDESC_H
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/*
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* Core internal functions to deal with irq descriptors
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*/
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struct irq_affinity_notify;
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struct proc_dir_entry;
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struct module;
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struct irq_desc;
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struct irq_domain;
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struct pt_regs;
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/**
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* struct irq_desc - interrupt descriptor
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* @irq_common_data: per irq and chip data passed down to chip functions
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* @kstat_irqs: irq stats per cpu
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* @handle_irq: highlevel irq-events handler
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* @preflow_handler: handler called before the flow handler (currently used by sparc)
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* @action: the irq action chain
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* @status: status information
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* @core_internal_state__do_not_mess_with_it: core internal status information
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* @depth: disable-depth, for nested irq_disable() calls
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* @wake_depth: enable depth, for multiple irq_set_irq_wake() callers
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* @irq_count: stats field to detect stalled irqs
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* @last_unhandled: aging timer for unhandled count
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* @irqs_unhandled: stats field for spurious unhandled interrupts
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* @threads_handled: stats field for deferred spurious detection of threaded handlers
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* @threads_handled_last: comparator field for deferred spurious detection of theraded handlers
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* @lock: locking for SMP
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* @affinity_hint: hint to user space for preferred irq affinity
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* @affinity_notify: context for notification of affinity changes
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* @pending_mask: pending rebalanced interrupts
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* @threads_oneshot: bitfield to handle shared oneshot threads
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* @threads_active: number of irqaction threads currently running
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* @wait_for_threads: wait queue for sync_irq to wait for threaded handlers
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* @nr_actions: number of installed actions on this descriptor
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* @no_suspend_depth: number of irqactions on a irq descriptor with
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* IRQF_NO_SUSPEND set
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* @force_resume_depth: number of irqactions on a irq descriptor with
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* IRQF_FORCE_RESUME set
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* @dir: /proc/irq/ procfs entry
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* @name: flow handler name for /proc/interrupts output
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*/
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struct irq_desc {
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struct irq_common_data irq_common_data;
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struct irq_data irq_data;
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unsigned int __percpu *kstat_irqs;
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irq_flow_handler_t handle_irq;
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#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
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irq_preflow_handler_t preflow_handler;
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#endif
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struct irqaction *action; /* IRQ action list */
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unsigned int status_use_accessors;
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unsigned int core_internal_state__do_not_mess_with_it;
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unsigned int depth; /* nested irq disables */
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unsigned int wake_depth; /* nested wake enables */
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unsigned int irq_count; /* For detecting broken IRQs */
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unsigned long last_unhandled; /* Aging timer for unhandled count */
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unsigned int irqs_unhandled;
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atomic_t threads_handled;
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int threads_handled_last;
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raw_spinlock_t lock;
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struct cpumask *percpu_enabled;
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#ifdef CONFIG_SMP
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const struct cpumask *affinity_hint;
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struct irq_affinity_notify *affinity_notify;
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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cpumask_var_t pending_mask;
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#endif
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#endif
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unsigned long threads_oneshot;
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atomic_t threads_active;
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wait_queue_head_t wait_for_threads;
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#ifdef CONFIG_PM_SLEEP
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unsigned int nr_actions;
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unsigned int no_suspend_depth;
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unsigned int cond_suspend_depth;
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unsigned int force_resume_depth;
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#endif
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#ifdef CONFIG_PROC_FS
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struct proc_dir_entry *dir;
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#endif
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int parent_irq;
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struct module *owner;
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const char *name;
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} ____cacheline_internodealigned_in_smp;
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#ifdef CONFIG_SPARSE_IRQ
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extern void irq_lock_sparse(void);
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extern void irq_unlock_sparse(void);
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#else
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static inline void irq_lock_sparse(void) { }
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static inline void irq_unlock_sparse(void) { }
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extern struct irq_desc irq_desc[NR_IRQS];
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#endif
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static inline struct irq_desc *irq_data_to_desc(struct irq_data *data)
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{
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#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
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return irq_to_desc(data->irq);
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#else
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return container_of(data, struct irq_desc, irq_data);
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#endif
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}
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static inline unsigned int irq_desc_get_irq(struct irq_desc *desc)
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{
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return desc->irq_data.irq;
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}
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static inline struct irq_data *irq_desc_get_irq_data(struct irq_desc *desc)
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{
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return &desc->irq_data;
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}
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static inline struct irq_chip *irq_desc_get_chip(struct irq_desc *desc)
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{
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return desc->irq_data.chip;
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}
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static inline void *irq_desc_get_chip_data(struct irq_desc *desc)
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{
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return desc->irq_data.chip_data;
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}
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static inline void *irq_desc_get_handler_data(struct irq_desc *desc)
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{
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return desc->irq_data.handler_data;
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}
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static inline struct msi_desc *irq_desc_get_msi_desc(struct irq_desc *desc)
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{
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return desc->irq_data.msi_desc;
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}
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/*
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* Architectures call this to let the generic IRQ layer
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* handle an interrupt. If the descriptor is attached to an
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* irqchip-style controller then we call the ->handle_irq() handler,
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* and it calls __do_IRQ() if it's attached to an irqtype-style controller.
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*/
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static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *desc)
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{
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desc->handle_irq(irq, desc);
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}
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int generic_handle_irq(unsigned int irq);
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#ifdef CONFIG_HANDLE_DOMAIN_IRQ
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/*
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* Convert a HW interrupt number to a logical one using a IRQ domain,
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* and handle the result interrupt number. Return -EINVAL if
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* conversion failed. Providing a NULL domain indicates that the
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* conversion has already been done.
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*/
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int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
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bool lookup, struct pt_regs *regs);
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static inline int handle_domain_irq(struct irq_domain *domain,
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unsigned int hwirq, struct pt_regs *regs)
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{
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return __handle_domain_irq(domain, hwirq, true, regs);
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}
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#endif
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/* Test to see if a driver has successfully requested an irq */
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static inline int irq_has_action(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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return desc->action != NULL;
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}
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/* caller has locked the irq_desc and both params are valid */
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static inline void __irq_set_handler_locked(unsigned int irq,
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irq_flow_handler_t handler)
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{
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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desc->handle_irq = handler;
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}
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/* caller has locked the irq_desc and both params are valid */
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static inline void
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__irq_set_chip_handler_name_locked(unsigned int irq, struct irq_chip *chip,
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irq_flow_handler_t handler, const char *name)
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{
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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irq_desc_get_irq_data(desc)->chip = chip;
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desc->handle_irq = handler;
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desc->name = name;
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}
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/**
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* irq_set_handler_locked - Set irq handler from a locked region
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* @data: Pointer to the irq_data structure which identifies the irq
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* @handler: Flow control handler function for this interrupt
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*
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* Sets the handler in the irq descriptor associated to @data.
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*
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* Must be called with irq_desc locked and valid parameters. Typical
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* call site is the irq_set_type() callback.
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*/
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static inline void irq_set_handler_locked(struct irq_data *data,
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irq_flow_handler_t handler)
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{
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struct irq_desc *desc = irq_data_to_desc(data);
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desc->handle_irq = handler;
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}
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/**
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* irq_set_chip_handler_name_locked - Set chip, handler and name from a locked region
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* @data: Pointer to the irq_data structure for which the chip is set
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* @chip: Pointer to the new irq chip
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* @handler: Flow control handler function for this interrupt
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* @name: Name of the interrupt
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*
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* Replace the irq chip at the proper hierarchy level in @data and
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* sets the handler and name in the associated irq descriptor.
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*
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* Must be called with irq_desc locked and valid parameters.
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*/
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static inline void
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irq_set_chip_handler_name_locked(struct irq_data *data, struct irq_chip *chip,
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irq_flow_handler_t handler, const char *name)
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{
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struct irq_desc *desc = irq_data_to_desc(data);
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desc->handle_irq = handler;
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desc->name = name;
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data->chip = chip;
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}
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static inline int irq_balancing_disabled(unsigned int irq)
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{
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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return desc->status_use_accessors & IRQ_NO_BALANCING_MASK;
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}
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static inline int irq_is_percpu(unsigned int irq)
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{
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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return desc->status_use_accessors & IRQ_PER_CPU;
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}
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static inline void
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irq_set_lockdep_class(unsigned int irq, struct lock_class_key *class)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (desc)
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lockdep_set_class(&desc->lock, class);
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}
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#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
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static inline void
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__irq_set_preflow_handler(unsigned int irq, irq_preflow_handler_t handler)
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{
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struct irq_desc *desc;
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desc = irq_to_desc(irq);
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desc->preflow_handler = handler;
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}
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#endif
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#endif
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