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linux-next/include/linux/irqdesc.h
Thomas Gleixner 1e77d0a1ed genirq: Sanitize spurious interrupt detection of threaded irqs
Till reported that the spurious interrupt detection of threaded
interrupts is broken in two ways:

- note_interrupt() is called for each action thread of a shared
  interrupt line. That's wrong as we are only interested whether none
  of the device drivers felt responsible for the interrupt, but by
  calling multiple times for a single interrupt line we account
  IRQ_NONE even if one of the drivers felt responsible.

- note_interrupt() when called from the thread handler is not
  serialized. That leaves the members of irq_desc which are used for
  the spurious detection unprotected.

To solve this we need to defer the spurious detection of a threaded
interrupt to the next hardware interrupt context where we have
implicit serialization.

If note_interrupt is called with action_ret == IRQ_WAKE_THREAD, we
check whether the previous interrupt requested a deferred check. If
not, we request a deferred check for the next hardware interrupt and
return. 

If set, we check whether one of the interrupt threads signaled
success. Depending on this information we feed the result into the
spurious detector.

If one primary handler of a shared interrupt returns IRQ_HANDLED we
disable the deferred check of irq threads on the same line, as we have
found at least one device driver who cared.

Reported-by: Till Straumann <strauman@slac.stanford.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Austin Schuh <austin@peloton-tech.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: linux-can@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1303071450130.22263@ionos
2014-05-03 23:15:39 +02:00

188 lines
5.4 KiB
C

#ifndef _LINUX_IRQDESC_H
#define _LINUX_IRQDESC_H
/*
* Core internal functions to deal with irq descriptors
*
* This include will move to kernel/irq once we cleaned up the tree.
* For now it's included from <linux/irq.h>
*/
struct irq_affinity_notify;
struct proc_dir_entry;
struct module;
struct irq_desc;
/**
* struct irq_desc - interrupt descriptor
* @irq_data: per irq and chip data passed down to chip functions
* @kstat_irqs: irq stats per cpu
* @handle_irq: highlevel irq-events handler
* @preflow_handler: handler called before the flow handler (currently used by sparc)
* @action: the irq action chain
* @status: status information
* @core_internal_state__do_not_mess_with_it: core internal status information
* @depth: disable-depth, for nested irq_disable() calls
* @wake_depth: enable depth, for multiple irq_set_irq_wake() callers
* @irq_count: stats field to detect stalled irqs
* @last_unhandled: aging timer for unhandled count
* @irqs_unhandled: stats field for spurious unhandled interrupts
* @threads_handled: stats field for deferred spurious detection of threaded handlers
* @threads_handled_last: comparator field for deferred spurious detection of theraded handlers
* @lock: locking for SMP
* @affinity_hint: hint to user space for preferred irq affinity
* @affinity_notify: context for notification of affinity changes
* @pending_mask: pending rebalanced interrupts
* @threads_oneshot: bitfield to handle shared oneshot threads
* @threads_active: number of irqaction threads currently running
* @wait_for_threads: wait queue for sync_irq to wait for threaded handlers
* @dir: /proc/irq/ procfs entry
* @name: flow handler name for /proc/interrupts output
*/
struct irq_desc {
struct irq_data irq_data;
unsigned int __percpu *kstat_irqs;
irq_flow_handler_t handle_irq;
#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
irq_preflow_handler_t preflow_handler;
#endif
struct irqaction *action; /* IRQ action list */
unsigned int status_use_accessors;
unsigned int core_internal_state__do_not_mess_with_it;
unsigned int depth; /* nested irq disables */
unsigned int wake_depth; /* nested wake enables */
unsigned int irq_count; /* For detecting broken IRQs */
unsigned long last_unhandled; /* Aging timer for unhandled count */
unsigned int irqs_unhandled;
atomic_t threads_handled;
int threads_handled_last;
raw_spinlock_t lock;
struct cpumask *percpu_enabled;
#ifdef CONFIG_SMP
const struct cpumask *affinity_hint;
struct irq_affinity_notify *affinity_notify;
#ifdef CONFIG_GENERIC_PENDING_IRQ
cpumask_var_t pending_mask;
#endif
#endif
unsigned long threads_oneshot;
atomic_t threads_active;
wait_queue_head_t wait_for_threads;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *dir;
#endif
int parent_irq;
struct module *owner;
const char *name;
} ____cacheline_internodealigned_in_smp;
#ifndef CONFIG_SPARSE_IRQ
extern struct irq_desc irq_desc[NR_IRQS];
#endif
static inline struct irq_data *irq_desc_get_irq_data(struct irq_desc *desc)
{
return &desc->irq_data;
}
static inline struct irq_chip *irq_desc_get_chip(struct irq_desc *desc)
{
return desc->irq_data.chip;
}
static inline void *irq_desc_get_chip_data(struct irq_desc *desc)
{
return desc->irq_data.chip_data;
}
static inline void *irq_desc_get_handler_data(struct irq_desc *desc)
{
return desc->irq_data.handler_data;
}
static inline struct msi_desc *irq_desc_get_msi_desc(struct irq_desc *desc)
{
return desc->irq_data.msi_desc;
}
/*
* Architectures call this to let the generic IRQ layer
* handle an interrupt. If the descriptor is attached to an
* irqchip-style controller then we call the ->handle_irq() handler,
* and it calls __do_IRQ() if it's attached to an irqtype-style controller.
*/
static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *desc)
{
desc->handle_irq(irq, desc);
}
int generic_handle_irq(unsigned int irq);
/* Test to see if a driver has successfully requested an irq */
static inline int irq_has_action(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
return desc->action != NULL;
}
/* caller has locked the irq_desc and both params are valid */
static inline void __irq_set_handler_locked(unsigned int irq,
irq_flow_handler_t handler)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
desc->handle_irq = handler;
}
/* caller has locked the irq_desc and both params are valid */
static inline void
__irq_set_chip_handler_name_locked(unsigned int irq, struct irq_chip *chip,
irq_flow_handler_t handler, const char *name)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
irq_desc_get_irq_data(desc)->chip = chip;
desc->handle_irq = handler;
desc->name = name;
}
static inline int irq_balancing_disabled(unsigned int irq)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
return desc->status_use_accessors & IRQ_NO_BALANCING_MASK;
}
static inline int irq_is_percpu(unsigned int irq)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
return desc->status_use_accessors & IRQ_PER_CPU;
}
static inline void
irq_set_lockdep_class(unsigned int irq, struct lock_class_key *class)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc)
lockdep_set_class(&desc->lock, class);
}
#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
static inline void
__irq_set_preflow_handler(unsigned int irq, irq_preflow_handler_t handler)
{
struct irq_desc *desc;
desc = irq_to_desc(irq);
desc->preflow_handler = handler;
}
#endif
#endif