linux/kernel/irq/manage.c
Lukas Wunner 746a923b86 genirq: Fix race on spurious interrupt detection
Commit 1e77d0a1ed ("genirq: Sanitize spurious interrupt detection of
threaded irqs") made detection of spurious interrupts work for threaded
handlers by:

a) incrementing a counter every time the thread returns IRQ_HANDLED, and
b) checking whether that counter has increased every time the thread is
   woken.

However for oneshot interrupts, the commit unmasks the interrupt before
incrementing the counter.  If another interrupt occurs right after
unmasking but before the counter is incremented, that interrupt is
incorrectly considered spurious:

time
 |  irq_thread()
 |    irq_thread_fn()
 |      action->thread_fn()
 |      irq_finalize_oneshot()
 |        unmask_threaded_irq()            /* interrupt is unmasked */
 |
 |                  /* interrupt fires, incorrectly deemed spurious */
 |
 |    atomic_inc(&desc->threads_handled); /* counter is incremented */
 v

This is observed with a hi3110 CAN controller receiving data at high volume
(from a separate machine sending with "cangen -g 0 -i -x"): The controller
signals a huge number of interrupts (hundreds of millions per day) and
every second there are about a dozen which are deemed spurious.

In theory with high CPU load and the presence of higher priority tasks, the
number of incorrectly detected spurious interrupts might increase beyond
the 99,900 threshold and cause disablement of the interrupt.

In practice it just increments the spurious interrupt count. But that can
cause people to waste time investigating it over and over.

Fix it by moving the accounting before the invocation of
irq_finalize_oneshot().

[ tglx: Folded change log update ]

Fixes: 1e77d0a1ed ("genirq: Sanitize spurious interrupt detection of threaded irqs")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Akshay Bhat <akshay.bhat@timesys.com>
Cc: Casey Fitzpatrick <casey.fitzpatrick@timesys.com>
Cc: stable@vger.kernel.org # v3.16+
Link: https://lkml.kernel.org/r/1dfd8bbd16163940648045495e3e9698e63b50ad.1539867047.git.lukas@wunner.de
2018-10-19 17:31:00 +02:00

2263 lines
59 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
* Copyright (C) 2005-2006 Thomas Gleixner
*
* This file contains driver APIs to the irq subsystem.
*/
#define pr_fmt(fmt) "genirq: " fmt
#include <linux/irq.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/sched/rt.h>
#include <linux/sched/task.h>
#include <uapi/linux/sched/types.h>
#include <linux/task_work.h>
#include "internals.h"
#ifdef CONFIG_IRQ_FORCED_THREADING
__read_mostly bool force_irqthreads;
EXPORT_SYMBOL_GPL(force_irqthreads);
static int __init setup_forced_irqthreads(char *arg)
{
force_irqthreads = true;
return 0;
}
early_param("threadirqs", setup_forced_irqthreads);
#endif
static void __synchronize_hardirq(struct irq_desc *desc)
{
bool inprogress;
do {
unsigned long flags;
/*
* Wait until we're out of the critical section. This might
* give the wrong answer due to the lack of memory barriers.
*/
while (irqd_irq_inprogress(&desc->irq_data))
cpu_relax();
/* Ok, that indicated we're done: double-check carefully. */
raw_spin_lock_irqsave(&desc->lock, flags);
inprogress = irqd_irq_inprogress(&desc->irq_data);
raw_spin_unlock_irqrestore(&desc->lock, flags);
/* Oops, that failed? */
} while (inprogress);
}
/**
* synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
* @irq: interrupt number to wait for
*
* This function waits for any pending hard IRQ handlers for this
* interrupt to complete before returning. If you use this
* function while holding a resource the IRQ handler may need you
* will deadlock. It does not take associated threaded handlers
* into account.
*
* Do not use this for shutdown scenarios where you must be sure
* that all parts (hardirq and threaded handler) have completed.
*
* Returns: false if a threaded handler is active.
*
* This function may be called - with care - from IRQ context.
*/
bool synchronize_hardirq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc) {
__synchronize_hardirq(desc);
return !atomic_read(&desc->threads_active);
}
return true;
}
EXPORT_SYMBOL(synchronize_hardirq);
/**
* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
* @irq: interrupt number to wait for
*
* This function waits for any pending IRQ handlers for this interrupt
* to complete before returning. If you use this function while
* holding a resource the IRQ handler may need you will deadlock.
*
* This function may be called - with care - from IRQ context.
*/
void synchronize_irq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc) {
__synchronize_hardirq(desc);
/*
* We made sure that no hardirq handler is
* running. Now verify that no threaded handlers are
* active.
*/
wait_event(desc->wait_for_threads,
!atomic_read(&desc->threads_active));
}
}
EXPORT_SYMBOL(synchronize_irq);
#ifdef CONFIG_SMP
cpumask_var_t irq_default_affinity;
static bool __irq_can_set_affinity(struct irq_desc *desc)
{
if (!desc || !irqd_can_balance(&desc->irq_data) ||
!desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
return false;
return true;
}
/**
* irq_can_set_affinity - Check if the affinity of a given irq can be set
* @irq: Interrupt to check
*
*/
int irq_can_set_affinity(unsigned int irq)
{
return __irq_can_set_affinity(irq_to_desc(irq));
}
/**
* irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
* @irq: Interrupt to check
*
* Like irq_can_set_affinity() above, but additionally checks for the
* AFFINITY_MANAGED flag.
*/
bool irq_can_set_affinity_usr(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
return __irq_can_set_affinity(desc) &&
!irqd_affinity_is_managed(&desc->irq_data);
}
/**
* irq_set_thread_affinity - Notify irq threads to adjust affinity
* @desc: irq descriptor which has affitnity changed
*
* We just set IRQTF_AFFINITY and delegate the affinity setting
* to the interrupt thread itself. We can not call
* set_cpus_allowed_ptr() here as we hold desc->lock and this
* code can be called from hard interrupt context.
*/
void irq_set_thread_affinity(struct irq_desc *desc)
{
struct irqaction *action;
for_each_action_of_desc(desc, action)
if (action->thread)
set_bit(IRQTF_AFFINITY, &action->thread_flags);
}
static void irq_validate_effective_affinity(struct irq_data *data)
{
#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
struct irq_chip *chip = irq_data_get_irq_chip(data);
if (!cpumask_empty(m))
return;
pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
chip->name, data->irq);
#endif
}
int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
bool force)
{
struct irq_desc *desc = irq_data_to_desc(data);
struct irq_chip *chip = irq_data_get_irq_chip(data);
int ret;
if (!chip || !chip->irq_set_affinity)
return -EINVAL;
ret = chip->irq_set_affinity(data, mask, force);
switch (ret) {
case IRQ_SET_MASK_OK:
case IRQ_SET_MASK_OK_DONE:
cpumask_copy(desc->irq_common_data.affinity, mask);
case IRQ_SET_MASK_OK_NOCOPY:
irq_validate_effective_affinity(data);
irq_set_thread_affinity(desc);
ret = 0;
}
return ret;
}
#ifdef CONFIG_GENERIC_PENDING_IRQ
static inline int irq_set_affinity_pending(struct irq_data *data,
const struct cpumask *dest)
{
struct irq_desc *desc = irq_data_to_desc(data);
irqd_set_move_pending(data);
irq_copy_pending(desc, dest);
return 0;
}
#else
static inline int irq_set_affinity_pending(struct irq_data *data,
const struct cpumask *dest)
{
return -EBUSY;
}
#endif
static int irq_try_set_affinity(struct irq_data *data,
const struct cpumask *dest, bool force)
{
int ret = irq_do_set_affinity(data, dest, force);
/*
* In case that the underlying vector management is busy and the
* architecture supports the generic pending mechanism then utilize
* this to avoid returning an error to user space.
*/
if (ret == -EBUSY && !force)
ret = irq_set_affinity_pending(data, dest);
return ret;
}
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);
int ret = 0;
if (!chip || !chip->irq_set_affinity)
return -EINVAL;
if (irq_can_move_pcntxt(data) && !irqd_is_setaffinity_pending(data)) {
ret = irq_try_set_affinity(data, mask, force);
} else {
irqd_set_move_pending(data);
irq_copy_pending(desc, mask);
}
if (desc->affinity_notify) {
kref_get(&desc->affinity_notify->kref);
schedule_work(&desc->affinity_notify->work);
}
irqd_set(data, IRQD_AFFINITY_SET);
return ret;
}
int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
{
struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
int ret;
if (!desc)
return -EINVAL;
raw_spin_lock_irqsave(&desc->lock, flags);
ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
raw_spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
if (!desc)
return -EINVAL;
desc->affinity_hint = m;
irq_put_desc_unlock(desc, flags);
/* set the initial affinity to prevent every interrupt being on CPU0 */
if (m)
__irq_set_affinity(irq, m, false);
return 0;
}
EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
static void irq_affinity_notify(struct work_struct *work)
{
struct irq_affinity_notify *notify =
container_of(work, struct irq_affinity_notify, work);
struct irq_desc *desc = irq_to_desc(notify->irq);
cpumask_var_t cpumask;
unsigned long flags;
if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
goto out;
raw_spin_lock_irqsave(&desc->lock, flags);
if (irq_move_pending(&desc->irq_data))
irq_get_pending(cpumask, desc);
else
cpumask_copy(cpumask, desc->irq_common_data.affinity);
raw_spin_unlock_irqrestore(&desc->lock, flags);
notify->notify(notify, cpumask);
free_cpumask_var(cpumask);
out:
kref_put(&notify->kref, notify->release);
}
/**
* irq_set_affinity_notifier - control notification of IRQ affinity changes
* @irq: Interrupt for which to enable/disable notification
* @notify: Context for notification, or %NULL to disable
* notification. Function pointers must be initialised;
* the other fields will be initialised by this function.
*
* Must be called in process context. Notification may only be enabled
* after the IRQ is allocated and must be disabled before the IRQ is
* freed using free_irq().
*/
int
irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irq_affinity_notify *old_notify;
unsigned long flags;
/* The release function is promised process context */
might_sleep();
if (!desc)
return -EINVAL;
/* Complete initialisation of *notify */
if (notify) {
notify->irq = irq;
kref_init(&notify->kref);
INIT_WORK(&notify->work, irq_affinity_notify);
}
raw_spin_lock_irqsave(&desc->lock, flags);
old_notify = desc->affinity_notify;
desc->affinity_notify = notify;
raw_spin_unlock_irqrestore(&desc->lock, flags);
if (old_notify)
kref_put(&old_notify->kref, old_notify->release);
return 0;
}
EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
#ifndef CONFIG_AUTO_IRQ_AFFINITY
/*
* Generic version of the affinity autoselector.
*/
int irq_setup_affinity(struct irq_desc *desc)
{
struct cpumask *set = irq_default_affinity;
int ret, node = irq_desc_get_node(desc);
static DEFINE_RAW_SPINLOCK(mask_lock);
static struct cpumask mask;
/* Excludes PER_CPU and NO_BALANCE interrupts */
if (!__irq_can_set_affinity(desc))
return 0;
raw_spin_lock(&mask_lock);
/*
* Preserve the managed affinity setting and a userspace affinity
* setup, but make sure that one of the targets is online.
*/
if (irqd_affinity_is_managed(&desc->irq_data) ||
irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
if (cpumask_intersects(desc->irq_common_data.affinity,
cpu_online_mask))
set = desc->irq_common_data.affinity;
else
irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
}
cpumask_and(&mask, cpu_online_mask, set);
if (node != NUMA_NO_NODE) {
const struct cpumask *nodemask = cpumask_of_node(node);
/* make sure at least one of the cpus in nodemask is online */
if (cpumask_intersects(&mask, nodemask))
cpumask_and(&mask, &mask, nodemask);
}
ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
raw_spin_unlock(&mask_lock);
return ret;
}
#else
/* Wrapper for ALPHA specific affinity selector magic */
int irq_setup_affinity(struct irq_desc *desc)
{
return irq_select_affinity(irq_desc_get_irq(desc));
}
#endif
/*
* Called when a bogus affinity is set via /proc/irq
*/
int irq_select_affinity_usr(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&desc->lock, flags);
ret = irq_setup_affinity(desc);
raw_spin_unlock_irqrestore(&desc->lock, flags);
return ret;
}
#endif
/**
* irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
* @irq: interrupt number to set affinity
* @vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
* specific data for percpu_devid interrupts
*
* This function uses the vCPU specific data to set the vCPU
* affinity for an irq. The vCPU specific data is passed from
* outside, such as KVM. One example code path is as below:
* KVM -> IOMMU -> irq_set_vcpu_affinity().
*/
int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
struct irq_data *data;
struct irq_chip *chip;
int ret = -ENOSYS;
if (!desc)
return -EINVAL;
data = irq_desc_get_irq_data(desc);
do {
chip = irq_data_get_irq_chip(data);
if (chip && chip->irq_set_vcpu_affinity)
break;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
data = data->parent_data;
#else
data = NULL;
#endif
} while (data);
if (data)
ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
irq_put_desc_unlock(desc, flags);
return ret;
}
EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
void __disable_irq(struct irq_desc *desc)
{
if (!desc->depth++)
irq_disable(desc);
}
static int __disable_irq_nosync(unsigned int irq)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
if (!desc)
return -EINVAL;
__disable_irq(desc);
irq_put_desc_busunlock(desc, flags);
return 0;
}
/**
* disable_irq_nosync - disable an irq without waiting
* @irq: Interrupt to disable
*
* Disable the selected interrupt line. Disables and Enables are
* nested.
* Unlike disable_irq(), this function does not ensure existing
* instances of the IRQ handler have completed before returning.
*
* This function may be called from IRQ context.
*/
void disable_irq_nosync(unsigned int irq)
{
__disable_irq_nosync(irq);
}
EXPORT_SYMBOL(disable_irq_nosync);
/**
* disable_irq - disable an irq and wait for completion
* @irq: Interrupt to disable
*
* Disable the selected interrupt line. Enables and Disables are
* nested.
* This function waits for any pending IRQ handlers for this interrupt
* to complete before returning. If you use this function while
* holding a resource the IRQ handler may need you will deadlock.
*
* This function may be called - with care - from IRQ context.
*/
void disable_irq(unsigned int irq)
{
if (!__disable_irq_nosync(irq))
synchronize_irq(irq);
}
EXPORT_SYMBOL(disable_irq);
/**
* disable_hardirq - disables an irq and waits for hardirq completion
* @irq: Interrupt to disable
*
* Disable the selected interrupt line. Enables and Disables are
* nested.
* This function waits for any pending hard IRQ handlers for this
* interrupt to complete before returning. If you use this function while
* holding a resource the hard IRQ handler may need you will deadlock.
*
* When used to optimistically disable an interrupt from atomic context
* the return value must be checked.
*
* Returns: false if a threaded handler is active.
*
* This function may be called - with care - from IRQ context.
*/
bool disable_hardirq(unsigned int irq)
{
if (!__disable_irq_nosync(irq))
return synchronize_hardirq(irq);
return false;
}
EXPORT_SYMBOL_GPL(disable_hardirq);
void __enable_irq(struct irq_desc *desc)
{
switch (desc->depth) {
case 0:
err_out:
WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
irq_desc_get_irq(desc));
break;
case 1: {
if (desc->istate & IRQS_SUSPENDED)
goto err_out;
/* Prevent probing on this irq: */
irq_settings_set_noprobe(desc);
/*
* Call irq_startup() not irq_enable() here because the
* interrupt might be marked NOAUTOEN. So irq_startup()
* needs to be invoked when it gets enabled the first
* time. If it was already started up, then irq_startup()
* will invoke irq_enable() under the hood.
*/
irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
break;
}
default:
desc->depth--;
}
}
/**
* enable_irq - enable handling of an irq
* @irq: Interrupt to enable
*
* Undoes the effect of one call to disable_irq(). If this
* matches the last disable, processing of interrupts on this
* IRQ line is re-enabled.
*
* This function may be called from IRQ context only when
* desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
*/
void enable_irq(unsigned int irq)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
if (!desc)
return;
if (WARN(!desc->irq_data.chip,
KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
goto out;
__enable_irq(desc);
out:
irq_put_desc_busunlock(desc, flags);
}
EXPORT_SYMBOL(enable_irq);
static int set_irq_wake_real(unsigned int irq, unsigned int on)
{
struct irq_desc *desc = irq_to_desc(irq);
int ret = -ENXIO;
if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
return 0;
if (desc->irq_data.chip->irq_set_wake)
ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
return ret;
}
/**
* irq_set_irq_wake - control irq power management wakeup
* @irq: interrupt to control
* @on: enable/disable power management wakeup
*
* Enable/disable power management wakeup mode, which is
* disabled by default. Enables and disables must match,
* just as they match for non-wakeup mode support.
*
* Wakeup mode lets this IRQ wake the system from sleep
* states like "suspend to RAM".
*/
int irq_set_irq_wake(unsigned int irq, unsigned int on)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
int ret = 0;
if (!desc)
return -EINVAL;
/* wakeup-capable irqs can be shared between drivers that
* don't need to have the same sleep mode behaviors.
*/
if (on) {
if (desc->wake_depth++ == 0) {
ret = set_irq_wake_real(irq, on);
if (ret)
desc->wake_depth = 0;
else
irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
}
} else {
if (desc->wake_depth == 0) {
WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
} else if (--desc->wake_depth == 0) {
ret = set_irq_wake_real(irq, on);
if (ret)
desc->wake_depth = 1;
else
irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
}
}
irq_put_desc_busunlock(desc, flags);
return ret;
}
EXPORT_SYMBOL(irq_set_irq_wake);
/*
* Internal function that tells the architecture code whether a
* particular irq has been exclusively allocated or is available
* for driver use.
*/
int can_request_irq(unsigned int irq, unsigned long irqflags)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
int canrequest = 0;
if (!desc)
return 0;
if (irq_settings_can_request(desc)) {
if (!desc->action ||
irqflags & desc->action->flags & IRQF_SHARED)
canrequest = 1;
}
irq_put_desc_unlock(desc, flags);
return canrequest;
}
int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
{
struct irq_chip *chip = desc->irq_data.chip;
int ret, unmask = 0;
if (!chip || !chip->irq_set_type) {
/*
* IRQF_TRIGGER_* but the PIC does not support multiple
* flow-types?
*/
pr_debug("No set_type function for IRQ %d (%s)\n",
irq_desc_get_irq(desc),
chip ? (chip->name ? : "unknown") : "unknown");
return 0;
}
if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
if (!irqd_irq_masked(&desc->irq_data))
mask_irq(desc);
if (!irqd_irq_disabled(&desc->irq_data))
unmask = 1;
}
/* Mask all flags except trigger mode */
flags &= IRQ_TYPE_SENSE_MASK;
ret = chip->irq_set_type(&desc->irq_data, flags);
switch (ret) {
case IRQ_SET_MASK_OK:
case IRQ_SET_MASK_OK_DONE:
irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
irqd_set(&desc->irq_data, flags);
case IRQ_SET_MASK_OK_NOCOPY:
flags = irqd_get_trigger_type(&desc->irq_data);
irq_settings_set_trigger_mask(desc, flags);
irqd_clear(&desc->irq_data, IRQD_LEVEL);
irq_settings_clr_level(desc);
if (flags & IRQ_TYPE_LEVEL_MASK) {
irq_settings_set_level(desc);
irqd_set(&desc->irq_data, IRQD_LEVEL);
}
ret = 0;
break;
default:
pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
flags, irq_desc_get_irq(desc), chip->irq_set_type);
}
if (unmask)
unmask_irq(desc);
return ret;
}
#ifdef CONFIG_HARDIRQS_SW_RESEND
int irq_set_parent(int irq, int parent_irq)
{
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
if (!desc)
return -EINVAL;
desc->parent_irq = parent_irq;
irq_put_desc_unlock(desc, flags);
return 0;
}
EXPORT_SYMBOL_GPL(irq_set_parent);
#endif
/*
* Default primary interrupt handler for threaded interrupts. Is
* assigned as primary handler when request_threaded_irq is called
* with handler == NULL. Useful for oneshot interrupts.
*/
static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
{
return IRQ_WAKE_THREAD;
}
/*
* Primary handler for nested threaded interrupts. Should never be
* called.
*/
static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
{
WARN(1, "Primary handler called for nested irq %d\n", irq);
return IRQ_NONE;
}
static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
{
WARN(1, "Secondary action handler called for irq %d\n", irq);
return IRQ_NONE;
}
static int irq_wait_for_interrupt(struct irqaction *action)
{
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
/* may need to run one last time */
if (test_and_clear_bit(IRQTF_RUNTHREAD,
&action->thread_flags)) {
__set_current_state(TASK_RUNNING);
return 0;
}
__set_current_state(TASK_RUNNING);
return -1;
}
if (test_and_clear_bit(IRQTF_RUNTHREAD,
&action->thread_flags)) {
__set_current_state(TASK_RUNNING);
return 0;
}
schedule();
}
}
/*
* Oneshot interrupts keep the irq line masked until the threaded
* handler finished. unmask if the interrupt has not been disabled and
* is marked MASKED.
*/
static void irq_finalize_oneshot(struct irq_desc *desc,
struct irqaction *action)
{
if (!(desc->istate & IRQS_ONESHOT) ||
action->handler == irq_forced_secondary_handler)
return;
again:
chip_bus_lock(desc);
raw_spin_lock_irq(&desc->lock);
/*
* Implausible though it may be we need to protect us against
* the following scenario:
*
* The thread is faster done than the hard interrupt handler
* on the other CPU. If we unmask the irq line then the
* interrupt can come in again and masks the line, leaves due
* to IRQS_INPROGRESS and the irq line is masked forever.
*
* This also serializes the state of shared oneshot handlers
* versus "desc->threads_onehsot |= action->thread_mask;" in
* irq_wake_thread(). See the comment there which explains the
* serialization.
*/
if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
raw_spin_unlock_irq(&desc->lock);
chip_bus_sync_unlock(desc);
cpu_relax();
goto again;
}
/*
* Now check again, whether the thread should run. Otherwise
* we would clear the threads_oneshot bit of this thread which
* was just set.
*/
if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
goto out_unlock;
desc->threads_oneshot &= ~action->thread_mask;
if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
irqd_irq_masked(&desc->irq_data))
unmask_threaded_irq(desc);
out_unlock:
raw_spin_unlock_irq(&desc->lock);
chip_bus_sync_unlock(desc);
}
#ifdef CONFIG_SMP
/*
* Check whether we need to change the affinity of the interrupt thread.
*/
static void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
{
cpumask_var_t mask;
bool valid = true;
if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
return;
/*
* In case we are out of memory we set IRQTF_AFFINITY again and
* try again next time
*/
if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
set_bit(IRQTF_AFFINITY, &action->thread_flags);
return;
}
raw_spin_lock_irq(&desc->lock);
/*
* This code is triggered unconditionally. Check the affinity
* mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
*/
if (cpumask_available(desc->irq_common_data.affinity)) {
const struct cpumask *m;
m = irq_data_get_effective_affinity_mask(&desc->irq_data);
cpumask_copy(mask, m);
} else {
valid = false;
}
raw_spin_unlock_irq(&desc->lock);
if (valid)
set_cpus_allowed_ptr(current, mask);
free_cpumask_var(mask);
}
#else
static inline void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
#endif
/*
* Interrupts which are not explicitely requested as threaded
* interrupts rely on the implicit bh/preempt disable of the hard irq
* context. So we need to disable bh here to avoid deadlocks and other
* side effects.
*/
static irqreturn_t
irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
{
irqreturn_t ret;
local_bh_disable();
ret = action->thread_fn(action->irq, action->dev_id);
if (ret == IRQ_HANDLED)
atomic_inc(&desc->threads_handled);
irq_finalize_oneshot(desc, action);
local_bh_enable();
return ret;
}
/*
* Interrupts explicitly requested as threaded interrupts want to be
* preemtible - many of them need to sleep and wait for slow busses to
* complete.
*/
static irqreturn_t irq_thread_fn(struct irq_desc *desc,
struct irqaction *action)
{
irqreturn_t ret;
ret = action->thread_fn(action->irq, action->dev_id);
if (ret == IRQ_HANDLED)
atomic_inc(&desc->threads_handled);
irq_finalize_oneshot(desc, action);
return ret;
}
static void wake_threads_waitq(struct irq_desc *desc)
{
if (atomic_dec_and_test(&desc->threads_active))
wake_up(&desc->wait_for_threads);
}
static void irq_thread_dtor(struct callback_head *unused)
{
struct task_struct *tsk = current;
struct irq_desc *desc;
struct irqaction *action;
if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
return;
action = kthread_data(tsk);
pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
tsk->comm, tsk->pid, action->irq);
desc = irq_to_desc(action->irq);
/*
* If IRQTF_RUNTHREAD is set, we need to decrement
* desc->threads_active and wake possible waiters.
*/
if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
wake_threads_waitq(desc);
/* Prevent a stale desc->threads_oneshot */
irq_finalize_oneshot(desc, action);
}
static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
{
struct irqaction *secondary = action->secondary;
if (WARN_ON_ONCE(!secondary))
return;
raw_spin_lock_irq(&desc->lock);
__irq_wake_thread(desc, secondary);
raw_spin_unlock_irq(&desc->lock);
}
/*
* Interrupt handler thread
*/
static int irq_thread(void *data)
{
struct callback_head on_exit_work;
struct irqaction *action = data;
struct irq_desc *desc = irq_to_desc(action->irq);
irqreturn_t (*handler_fn)(struct irq_desc *desc,
struct irqaction *action);
if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
&action->thread_flags))
handler_fn = irq_forced_thread_fn;
else
handler_fn = irq_thread_fn;
init_task_work(&on_exit_work, irq_thread_dtor);
task_work_add(current, &on_exit_work, false);
irq_thread_check_affinity(desc, action);
while (!irq_wait_for_interrupt(action)) {
irqreturn_t action_ret;
irq_thread_check_affinity(desc, action);
action_ret = handler_fn(desc, action);
if (action_ret == IRQ_WAKE_THREAD)
irq_wake_secondary(desc, action);
wake_threads_waitq(desc);
}
/*
* This is the regular exit path. __free_irq() is stopping the
* thread via kthread_stop() after calling
* synchronize_hardirq(). So neither IRQTF_RUNTHREAD nor the
* oneshot mask bit can be set.
*/
task_work_cancel(current, irq_thread_dtor);
return 0;
}
/**
* irq_wake_thread - wake the irq thread for the action identified by dev_id
* @irq: Interrupt line
* @dev_id: Device identity for which the thread should be woken
*
*/
void irq_wake_thread(unsigned int irq, void *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
unsigned long flags;
if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
return;
raw_spin_lock_irqsave(&desc->lock, flags);
for_each_action_of_desc(desc, action) {
if (action->dev_id == dev_id) {
if (action->thread)
__irq_wake_thread(desc, action);
break;
}
}
raw_spin_unlock_irqrestore(&desc->lock, flags);
}
EXPORT_SYMBOL_GPL(irq_wake_thread);
static int irq_setup_forced_threading(struct irqaction *new)
{
if (!force_irqthreads)
return 0;
if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
return 0;
/*
* No further action required for interrupts which are requested as
* threaded interrupts already
*/
if (new->handler == irq_default_primary_handler)
return 0;
new->flags |= IRQF_ONESHOT;
/*
* Handle the case where we have a real primary handler and a
* thread handler. We force thread them as well by creating a
* secondary action.
*/
if (new->handler && new->thread_fn) {
/* Allocate the secondary action */
new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!new->secondary)
return -ENOMEM;
new->secondary->handler = irq_forced_secondary_handler;
new->secondary->thread_fn = new->thread_fn;
new->secondary->dev_id = new->dev_id;
new->secondary->irq = new->irq;
new->secondary->name = new->name;
}
/* Deal with the primary handler */
set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
new->thread_fn = new->handler;
new->handler = irq_default_primary_handler;
return 0;
}
static int irq_request_resources(struct irq_desc *desc)
{
struct irq_data *d = &desc->irq_data;
struct irq_chip *c = d->chip;
return c->irq_request_resources ? c->irq_request_resources(d) : 0;
}
static void irq_release_resources(struct irq_desc *desc)
{
struct irq_data *d = &desc->irq_data;
struct irq_chip *c = d->chip;
if (c->irq_release_resources)
c->irq_release_resources(d);
}
static int
setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
{
struct task_struct *t;
struct sched_param param = {
.sched_priority = MAX_USER_RT_PRIO/2,
};
if (!secondary) {
t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
new->name);
} else {
t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
new->name);
param.sched_priority -= 1;
}
if (IS_ERR(t))
return PTR_ERR(t);
sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
/*
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code
* references an already freed task_struct.
*/
get_task_struct(t);
new->thread = t;
/*
* Tell the thread to set its affinity. This is
* important for shared interrupt handlers as we do
* not invoke setup_affinity() for the secondary
* handlers as everything is already set up. Even for
* interrupts marked with IRQF_NO_BALANCE this is
* correct as we want the thread to move to the cpu(s)
* on which the requesting code placed the interrupt.
*/
set_bit(IRQTF_AFFINITY, &new->thread_flags);
return 0;
}
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
*
* Locking rules:
*
* desc->request_mutex Provides serialization against a concurrent free_irq()
* chip_bus_lock Provides serialization for slow bus operations
* desc->lock Provides serialization against hard interrupts
*
* chip_bus_lock and desc->lock are sufficient for all other management and
* interrupt related functions. desc->request_mutex solely serializes
* request/free_irq().
*/
static int
__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
{
struct irqaction *old, **old_ptr;
unsigned long flags, thread_mask = 0;
int ret, nested, shared = 0;
if (!desc)
return -EINVAL;
if (desc->irq_data.chip == &no_irq_chip)
return -ENOSYS;
if (!try_module_get(desc->owner))
return -ENODEV;
new->irq = irq;
/*
* If the trigger type is not specified by the caller,
* then use the default for this interrupt.
*/
if (!(new->flags & IRQF_TRIGGER_MASK))
new->flags |= irqd_get_trigger_type(&desc->irq_data);
/*
* Check whether the interrupt nests into another interrupt
* thread.
*/
nested = irq_settings_is_nested_thread(desc);
if (nested) {
if (!new->thread_fn) {
ret = -EINVAL;
goto out_mput;
}
/*
* Replace the primary handler which was provided from
* the driver for non nested interrupt handling by the
* dummy function which warns when called.
*/
new->handler = irq_nested_primary_handler;
} else {
if (irq_settings_can_thread(desc)) {
ret = irq_setup_forced_threading(new);
if (ret)
goto out_mput;
}
}
/*
* Create a handler thread when a thread function is supplied
* and the interrupt does not nest into another interrupt
* thread.
*/
if (new->thread_fn && !nested) {
ret = setup_irq_thread(new, irq, false);
if (ret)
goto out_mput;
if (new->secondary) {
ret = setup_irq_thread(new->secondary, irq, true);
if (ret)
goto out_thread;
}
}
/*
* Drivers are often written to work w/o knowledge about the
* underlying irq chip implementation, so a request for a
* threaded irq without a primary hard irq context handler
* requires the ONESHOT flag to be set. Some irq chips like
* MSI based interrupts are per se one shot safe. Check the
* chip flags, so we can avoid the unmask dance at the end of
* the threaded handler for those.
*/
if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
new->flags &= ~IRQF_ONESHOT;
/*
* Protects against a concurrent __free_irq() call which might wait
* for synchronize_hardirq() to complete without holding the optional
* chip bus lock and desc->lock. Also protects against handing out
* a recycled oneshot thread_mask bit while it's still in use by
* its previous owner.
*/
mutex_lock(&desc->request_mutex);
/*
* Acquire bus lock as the irq_request_resources() callback below
* might rely on the serialization or the magic power management
* functions which are abusing the irq_bus_lock() callback,
*/
chip_bus_lock(desc);
/* First installed action requests resources. */
if (!desc->action) {
ret = irq_request_resources(desc);
if (ret) {
pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
new->name, irq, desc->irq_data.chip->name);
goto out_bus_unlock;
}
}
/*
* The following block of code has to be executed atomically
* protected against a concurrent interrupt and any of the other
* management calls which are not serialized via
* desc->request_mutex or the optional bus lock.
*/
raw_spin_lock_irqsave(&desc->lock, flags);
old_ptr = &desc->action;
old = *old_ptr;
if (old) {
/*
* Can't share interrupts unless both agree to and are
* the same type (level, edge, polarity). So both flag
* fields must have IRQF_SHARED set and the bits which
* set the trigger type must match. Also all must
* agree on ONESHOT.
*/
unsigned int oldtype;
/*
* If nobody did set the configuration before, inherit
* the one provided by the requester.
*/
if (irqd_trigger_type_was_set(&desc->irq_data)) {
oldtype = irqd_get_trigger_type(&desc->irq_data);
} else {
oldtype = new->flags & IRQF_TRIGGER_MASK;
irqd_set_trigger_type(&desc->irq_data, oldtype);
}
if (!((old->flags & new->flags) & IRQF_SHARED) ||
(oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
((old->flags ^ new->flags) & IRQF_ONESHOT))
goto mismatch;
/* All handlers must agree on per-cpuness */
if ((old->flags & IRQF_PERCPU) !=
(new->flags & IRQF_PERCPU))
goto mismatch;
/* add new interrupt at end of irq queue */
do {
/*
* Or all existing action->thread_mask bits,
* so we can find the next zero bit for this
* new action.
*/
thread_mask |= old->thread_mask;
old_ptr = &old->next;
old = *old_ptr;
} while (old);
shared = 1;
}
/*
* Setup the thread mask for this irqaction for ONESHOT. For
* !ONESHOT irqs the thread mask is 0 so we can avoid a
* conditional in irq_wake_thread().
*/
if (new->flags & IRQF_ONESHOT) {
/*
* Unlikely to have 32 resp 64 irqs sharing one line,
* but who knows.
*/
if (thread_mask == ~0UL) {
ret = -EBUSY;
goto out_unlock;
}
/*
* The thread_mask for the action is or'ed to
* desc->thread_active to indicate that the
* IRQF_ONESHOT thread handler has been woken, but not
* yet finished. The bit is cleared when a thread
* completes. When all threads of a shared interrupt
* line have completed desc->threads_active becomes
* zero and the interrupt line is unmasked. See
* handle.c:irq_wake_thread() for further information.
*
* If no thread is woken by primary (hard irq context)
* interrupt handlers, then desc->threads_active is
* also checked for zero to unmask the irq line in the
* affected hard irq flow handlers
* (handle_[fasteoi|level]_irq).
*
* The new action gets the first zero bit of
* thread_mask assigned. See the loop above which or's
* all existing action->thread_mask bits.
*/
new->thread_mask = 1UL << ffz(thread_mask);
} else if (new->handler == irq_default_primary_handler &&
!(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
/*
* The interrupt was requested with handler = NULL, so
* we use the default primary handler for it. But it
* does not have the oneshot flag set. In combination
* with level interrupts this is deadly, because the
* default primary handler just wakes the thread, then
* the irq lines is reenabled, but the device still
* has the level irq asserted. Rinse and repeat....
*
* While this works for edge type interrupts, we play
* it safe and reject unconditionally because we can't
* say for sure which type this interrupt really
* has. The type flags are unreliable as the
* underlying chip implementation can override them.
*/
pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
irq);
ret = -EINVAL;
goto out_unlock;
}
if (!shared) {
init_waitqueue_head(&desc->wait_for_threads);
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
ret = __irq_set_trigger(desc,
new->flags & IRQF_TRIGGER_MASK);
if (ret)
goto out_unlock;
}
/*
* Activate the interrupt. That activation must happen
* independently of IRQ_NOAUTOEN. request_irq() can fail
* and the callers are supposed to handle
* that. enable_irq() of an interrupt requested with
* IRQ_NOAUTOEN is not supposed to fail. The activation
* keeps it in shutdown mode, it merily associates
* resources if necessary and if that's not possible it
* fails. Interrupts which are in managed shutdown mode
* will simply ignore that activation request.
*/
ret = irq_activate(desc);
if (ret)
goto out_unlock;
desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
IRQS_ONESHOT | IRQS_WAITING);
irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
if (new->flags & IRQF_PERCPU) {
irqd_set(&desc->irq_data, IRQD_PER_CPU);
irq_settings_set_per_cpu(desc);
}
if (new->flags & IRQF_ONESHOT)
desc->istate |= IRQS_ONESHOT;
/* Exclude IRQ from balancing if requested */
if (new->flags & IRQF_NOBALANCING) {
irq_settings_set_no_balancing(desc);
irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
}
if (irq_settings_can_autoenable(desc)) {
irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
} else {
/*
* Shared interrupts do not go well with disabling
* auto enable. The sharing interrupt might request
* it while it's still disabled and then wait for
* interrupts forever.
*/
WARN_ON_ONCE(new->flags & IRQF_SHARED);
/* Undo nested disables: */
desc->depth = 1;
}
} else if (new->flags & IRQF_TRIGGER_MASK) {
unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
if (nmsk != omsk)
/* hope the handler works with current trigger mode */
pr_warn("irq %d uses trigger mode %u; requested %u\n",
irq, omsk, nmsk);
}
*old_ptr = new;
irq_pm_install_action(desc, new);
/* Reset broken irq detection when installing new handler */
desc->irq_count = 0;
desc->irqs_unhandled = 0;
/*
* Check whether we disabled the irq via the spurious handler
* before. Reenable it and give it another chance.
*/
if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
desc->istate &= ~IRQS_SPURIOUS_DISABLED;
__enable_irq(desc);
}
raw_spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(desc);
mutex_unlock(&desc->request_mutex);
irq_setup_timings(desc, new);
/*
* Strictly no need to wake it up, but hung_task complains
* when no hard interrupt wakes the thread up.
*/
if (new->thread)
wake_up_process(new->thread);
if (new->secondary)
wake_up_process(new->secondary->thread);
register_irq_proc(irq, desc);
new->dir = NULL;
register_handler_proc(irq, new);
return 0;
mismatch:
if (!(new->flags & IRQF_PROBE_SHARED)) {
pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
irq, new->flags, new->name, old->flags, old->name);
#ifdef CONFIG_DEBUG_SHIRQ
dump_stack();
#endif
}
ret = -EBUSY;
out_unlock:
raw_spin_unlock_irqrestore(&desc->lock, flags);
if (!desc->action)
irq_release_resources(desc);
out_bus_unlock:
chip_bus_sync_unlock(desc);
mutex_unlock(&desc->request_mutex);
out_thread:
if (new->thread) {
struct task_struct *t = new->thread;
new->thread = NULL;
kthread_stop(t);
put_task_struct(t);
}
if (new->secondary && new->secondary->thread) {
struct task_struct *t = new->secondary->thread;
new->secondary->thread = NULL;
kthread_stop(t);
put_task_struct(t);
}
out_mput:
module_put(desc->owner);
return ret;
}
/**
* setup_irq - setup an interrupt
* @irq: Interrupt line to setup
* @act: irqaction for the interrupt
*
* Used to statically setup interrupts in the early boot process.
*/
int setup_irq(unsigned int irq, struct irqaction *act)
{
int retval;
struct irq_desc *desc = irq_to_desc(irq);
if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
return -EINVAL;
retval = irq_chip_pm_get(&desc->irq_data);
if (retval < 0)
return retval;
retval = __setup_irq(irq, desc, act);
if (retval)
irq_chip_pm_put(&desc->irq_data);
return retval;
}
EXPORT_SYMBOL_GPL(setup_irq);
/*
* Internal function to unregister an irqaction - used to free
* regular and special interrupts that are part of the architecture.
*/
static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
{
unsigned irq = desc->irq_data.irq;
struct irqaction *action, **action_ptr;
unsigned long flags;
WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
mutex_lock(&desc->request_mutex);
chip_bus_lock(desc);
raw_spin_lock_irqsave(&desc->lock, flags);
/*
* There can be multiple actions per IRQ descriptor, find the right
* one based on the dev_id:
*/
action_ptr = &desc->action;
for (;;) {
action = *action_ptr;
if (!action) {
WARN(1, "Trying to free already-free IRQ %d\n", irq);
raw_spin_unlock_irqrestore(&desc->lock, flags);
chip_bus_sync_unlock(desc);
mutex_unlock(&desc->request_mutex);
return NULL;
}
if (action->dev_id == dev_id)
break;
action_ptr = &action->next;
}
/* Found it - now remove it from the list of entries: */
*action_ptr = action->next;
irq_pm_remove_action(desc, action);
/* If this was the last handler, shut down the IRQ line: */
if (!desc->action) {
irq_settings_clr_disable_unlazy(desc);
irq_shutdown(desc);
}
#ifdef CONFIG_SMP
/* make sure affinity_hint is cleaned up */
if (WARN_ON_ONCE(desc->affinity_hint))
desc->affinity_hint = NULL;
#endif
raw_spin_unlock_irqrestore(&desc->lock, flags);
/*
* Drop bus_lock here so the changes which were done in the chip
* callbacks above are synced out to the irq chips which hang
* behind a slow bus (I2C, SPI) before calling synchronize_hardirq().
*
* Aside of that the bus_lock can also be taken from the threaded
* handler in irq_finalize_oneshot() which results in a deadlock
* because kthread_stop() would wait forever for the thread to
* complete, which is blocked on the bus lock.
*
* The still held desc->request_mutex() protects against a
* concurrent request_irq() of this irq so the release of resources
* and timing data is properly serialized.
*/
chip_bus_sync_unlock(desc);
unregister_handler_proc(irq, action);
/* Make sure it's not being used on another CPU: */
synchronize_hardirq(irq);
#ifdef CONFIG_DEBUG_SHIRQ
/*
* It's a shared IRQ -- the driver ought to be prepared for an IRQ
* event to happen even now it's being freed, so let's make sure that
* is so by doing an extra call to the handler ....
*
* ( We do this after actually deregistering it, to make sure that a
* 'real' IRQ doesn't run in parallel with our fake. )
*/
if (action->flags & IRQF_SHARED) {
local_irq_save(flags);
action->handler(irq, dev_id);
local_irq_restore(flags);
}
#endif
/*
* The action has already been removed above, but the thread writes
* its oneshot mask bit when it completes. Though request_mutex is
* held across this which prevents __setup_irq() from handing out
* the same bit to a newly requested action.
*/
if (action->thread) {
kthread_stop(action->thread);
put_task_struct(action->thread);
if (action->secondary && action->secondary->thread) {
kthread_stop(action->secondary->thread);
put_task_struct(action->secondary->thread);
}
}
/* Last action releases resources */
if (!desc->action) {
/*
* Reaquire bus lock as irq_release_resources() might
* require it to deallocate resources over the slow bus.
*/
chip_bus_lock(desc);
irq_release_resources(desc);
chip_bus_sync_unlock(desc);
irq_remove_timings(desc);
}
mutex_unlock(&desc->request_mutex);
irq_chip_pm_put(&desc->irq_data);
module_put(desc->owner);
kfree(action->secondary);
return action;
}
/**
* remove_irq - free an interrupt
* @irq: Interrupt line to free
* @act: irqaction for the interrupt
*
* Used to remove interrupts statically setup by the early boot process.
*/
void remove_irq(unsigned int irq, struct irqaction *act)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
__free_irq(desc, act->dev_id);
}
EXPORT_SYMBOL_GPL(remove_irq);
/**
* free_irq - free an interrupt allocated with request_irq
* @irq: Interrupt line to free
* @dev_id: Device identity to free
*
* Remove an interrupt handler. The handler is removed and if the
* interrupt line is no longer in use by any driver it is disabled.
* On a shared IRQ the caller must ensure the interrupt is disabled
* on the card it drives before calling this function. The function
* does not return until any executing interrupts for this IRQ
* have completed.
*
* This function must not be called from interrupt context.
*
* Returns the devname argument passed to request_irq.
*/
const void *free_irq(unsigned int irq, void *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
const char *devname;
if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
return NULL;
#ifdef CONFIG_SMP
if (WARN_ON(desc->affinity_notify))
desc->affinity_notify = NULL;
#endif
action = __free_irq(desc, dev_id);
if (!action)
return NULL;
devname = action->name;
kfree(action);
return devname;
}
EXPORT_SYMBOL(free_irq);
/**
* request_threaded_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* Primary handler for threaded interrupts
* If NULL and thread_fn != NULL the default
* primary handler is installed
* @thread_fn: Function called from the irq handler thread
* If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt line and IRQ handling. From the point this
* call is made your handler function may be invoked. Since
* your handler function must clear any interrupt the board
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
* If you want to set up a threaded irq handler for your device
* then you need to supply @handler and @thread_fn. @handler is
* still called in hard interrupt context and has to check
* whether the interrupt originates from the device. If yes it
* needs to disable the interrupt on the device and return
* IRQ_WAKE_THREAD which will wake up the handler thread and run
* @thread_fn. This split handler design is necessary to support
* shared interrupts.
*
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
*
* If your interrupt is shared you must pass a non NULL dev_id
* as this is required when freeing the interrupt.
*
* Flags:
*
* IRQF_SHARED Interrupt is shared
* IRQF_TRIGGER_* Specify active edge(s) or level
*
*/
int request_threaded_irq(unsigned int irq, irq_handler_t handler,
irq_handler_t thread_fn, unsigned long irqflags,
const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
int retval;
if (irq == IRQ_NOTCONNECTED)
return -ENOTCONN;
/*
* Sanity-check: shared interrupts must pass in a real dev-ID,
* otherwise we'll have trouble later trying to figure out
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*
* Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
* it cannot be set along with IRQF_NO_SUSPEND.
*/
if (((irqflags & IRQF_SHARED) && !dev_id) ||
(!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
return -EINVAL;
desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
if (!irq_settings_can_request(desc) ||
WARN_ON(irq_settings_is_per_cpu_devid(desc)))
return -EINVAL;
if (!handler) {
if (!thread_fn)
return -EINVAL;
handler = irq_default_primary_handler;
}
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
action->thread_fn = thread_fn;
action->flags = irqflags;
action->name = devname;
action->dev_id = dev_id;
retval = irq_chip_pm_get(&desc->irq_data);
if (retval < 0) {
kfree(action);
return retval;
}
retval = __setup_irq(irq, desc, action);
if (retval) {
irq_chip_pm_put(&desc->irq_data);
kfree(action->secondary);
kfree(action);
}
#ifdef CONFIG_DEBUG_SHIRQ_FIXME
if (!retval && (irqflags & IRQF_SHARED)) {
/*
* It's a shared IRQ -- the driver ought to be prepared for it
* to happen immediately, so let's make sure....
* We disable the irq to make sure that a 'real' IRQ doesn't
* run in parallel with our fake.
*/
unsigned long flags;
disable_irq(irq);
local_irq_save(flags);
handler(irq, dev_id);
local_irq_restore(flags);
enable_irq(irq);
}
#endif
return retval;
}
EXPORT_SYMBOL(request_threaded_irq);
/**
* request_any_context_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* Threaded handler for threaded interrupts.
* @flags: Interrupt type flags
* @name: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt line and IRQ handling. It selects either a
* hardirq or threaded handling method depending on the
* context.
*
* On failure, it returns a negative value. On success,
* it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
*/
int request_any_context_irq(unsigned int irq, irq_handler_t handler,
unsigned long flags, const char *name, void *dev_id)
{
struct irq_desc *desc;
int ret;
if (irq == IRQ_NOTCONNECTED)
return -ENOTCONN;
desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
if (irq_settings_is_nested_thread(desc)) {
ret = request_threaded_irq(irq, NULL, handler,
flags, name, dev_id);
return !ret ? IRQC_IS_NESTED : ret;
}
ret = request_irq(irq, handler, flags, name, dev_id);
return !ret ? IRQC_IS_HARDIRQ : ret;
}
EXPORT_SYMBOL_GPL(request_any_context_irq);
void enable_percpu_irq(unsigned int irq, unsigned int type)
{
unsigned int cpu = smp_processor_id();
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
if (!desc)
return;
/*
* If the trigger type is not specified by the caller, then
* use the default for this interrupt.
*/
type &= IRQ_TYPE_SENSE_MASK;
if (type == IRQ_TYPE_NONE)
type = irqd_get_trigger_type(&desc->irq_data);
if (type != IRQ_TYPE_NONE) {
int ret;
ret = __irq_set_trigger(desc, type);
if (ret) {
WARN(1, "failed to set type for IRQ%d\n", irq);
goto out;
}
}
irq_percpu_enable(desc, cpu);
out:
irq_put_desc_unlock(desc, flags);
}
EXPORT_SYMBOL_GPL(enable_percpu_irq);
/**
* irq_percpu_is_enabled - Check whether the per cpu irq is enabled
* @irq: Linux irq number to check for
*
* Must be called from a non migratable context. Returns the enable
* state of a per cpu interrupt on the current cpu.
*/
bool irq_percpu_is_enabled(unsigned int irq)
{
unsigned int cpu = smp_processor_id();
struct irq_desc *desc;
unsigned long flags;
bool is_enabled;
desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
if (!desc)
return false;
is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
irq_put_desc_unlock(desc, flags);
return is_enabled;
}
EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
void disable_percpu_irq(unsigned int irq)
{
unsigned int cpu = smp_processor_id();
unsigned long flags;
struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
if (!desc)
return;
irq_percpu_disable(desc, cpu);
irq_put_desc_unlock(desc, flags);
}
EXPORT_SYMBOL_GPL(disable_percpu_irq);
/*
* Internal function to unregister a percpu irqaction.
*/
static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
unsigned long flags;
WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
if (!desc)
return NULL;
raw_spin_lock_irqsave(&desc->lock, flags);
action = desc->action;
if (!action || action->percpu_dev_id != dev_id) {
WARN(1, "Trying to free already-free IRQ %d\n", irq);
goto bad;
}
if (!cpumask_empty(desc->percpu_enabled)) {
WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
irq, cpumask_first(desc->percpu_enabled));
goto bad;
}
/* Found it - now remove it from the list of entries: */
desc->action = NULL;
raw_spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
irq_chip_pm_put(&desc->irq_data);
module_put(desc->owner);
return action;
bad:
raw_spin_unlock_irqrestore(&desc->lock, flags);
return NULL;
}
/**
* remove_percpu_irq - free a per-cpu interrupt
* @irq: Interrupt line to free
* @act: irqaction for the interrupt
*
* Used to remove interrupts statically setup by the early boot process.
*/
void remove_percpu_irq(unsigned int irq, struct irqaction *act)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc && irq_settings_is_per_cpu_devid(desc))
__free_percpu_irq(irq, act->percpu_dev_id);
}
/**
* free_percpu_irq - free an interrupt allocated with request_percpu_irq
* @irq: Interrupt line to free
* @dev_id: Device identity to free
*
* Remove a percpu interrupt handler. The handler is removed, but
* the interrupt line is not disabled. This must be done on each
* CPU before calling this function. The function does not return
* until any executing interrupts for this IRQ have completed.
*
* This function must not be called from interrupt context.
*/
void free_percpu_irq(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;
chip_bus_lock(desc);
kfree(__free_percpu_irq(irq, dev_id));
chip_bus_sync_unlock(desc);
}
EXPORT_SYMBOL_GPL(free_percpu_irq);
/**
* setup_percpu_irq - setup a per-cpu interrupt
* @irq: Interrupt line to setup
* @act: irqaction for the interrupt
*
* Used to statically setup per-cpu interrupts in the early boot process.
*/
int setup_percpu_irq(unsigned int irq, struct irqaction *act)
{
struct irq_desc *desc = irq_to_desc(irq);
int retval;
if (!desc || !irq_settings_is_per_cpu_devid(desc))
return -EINVAL;
retval = irq_chip_pm_get(&desc->irq_data);
if (retval < 0)
return retval;
retval = __setup_irq(irq, desc, act);
if (retval)
irq_chip_pm_put(&desc->irq_data);
return retval;
}
/**
* __request_percpu_irq - allocate a percpu interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* @flags: Interrupt type flags (IRQF_TIMER only)
* @devname: An ascii name for the claiming device
* @dev_id: A percpu cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt on the local CPU. If the interrupt is supposed to be
* enabled on other CPUs, it has to be done on each CPU using
* enable_percpu_irq().
*
* 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.
*/
int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
unsigned long flags, const char *devname,
void __percpu *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
int retval;
if (!dev_id)
return -EINVAL;
desc = irq_to_desc(irq);
if (!desc || !irq_settings_can_request(desc) ||
!irq_settings_is_per_cpu_devid(desc))
return -EINVAL;
if (flags && flags != IRQF_TIMER)
return -EINVAL;
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
action->name = devname;
action->percpu_dev_id = dev_id;
retval = irq_chip_pm_get(&desc->irq_data);
if (retval < 0) {
kfree(action);
return retval;
}
retval = __setup_irq(irq, desc, action);
if (retval) {
irq_chip_pm_put(&desc->irq_data);
kfree(action);
}
return retval;
}
EXPORT_SYMBOL_GPL(__request_percpu_irq);
/**
* irq_get_irqchip_state - returns the irqchip state of a interrupt.
* @irq: Interrupt line that is forwarded to a VM
* @which: One of IRQCHIP_STATE_* the caller wants to know about
* @state: a pointer to a boolean where the state is to be storeed
*
* This call snapshots the internal irqchip state of an
* interrupt, returning into @state the bit corresponding to
* stage @which
*
* This function should be called with preemption disabled if the
* interrupt controller has per-cpu registers.
*/
int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
bool *state)
{
struct irq_desc *desc;
struct irq_data *data;
struct irq_chip *chip;
unsigned long flags;
int err = -EINVAL;
desc = irq_get_desc_buslock(irq, &flags, 0);
if (!desc)
return err;
data = irq_desc_get_irq_data(desc);
do {
chip = irq_data_get_irq_chip(data);
if (chip->irq_get_irqchip_state)
break;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
data = data->parent_data;
#else
data = NULL;
#endif
} while (data);
if (data)
err = chip->irq_get_irqchip_state(data, which, state);
irq_put_desc_busunlock(desc, flags);
return err;
}
EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
/**
* irq_set_irqchip_state - set the state of a forwarded interrupt.
* @irq: Interrupt line that is forwarded to a VM
* @which: State to be restored (one of IRQCHIP_STATE_*)
* @val: Value corresponding to @which
*
* This call sets the internal irqchip state of an interrupt,
* depending on the value of @which.
*
* This function should be called with preemption disabled if the
* interrupt controller has per-cpu registers.
*/
int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
bool val)
{
struct irq_desc *desc;
struct irq_data *data;
struct irq_chip *chip;
unsigned long flags;
int err = -EINVAL;
desc = irq_get_desc_buslock(irq, &flags, 0);
if (!desc)
return err;
data = irq_desc_get_irq_data(desc);
do {
chip = irq_data_get_irq_chip(data);
if (chip->irq_set_irqchip_state)
break;
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
data = data->parent_data;
#else
data = NULL;
#endif
} while (data);
if (data)
err = chip->irq_set_irqchip_state(data, which, val);
irq_put_desc_busunlock(desc, flags);
return err;
}
EXPORT_SYMBOL_GPL(irq_set_irqchip_state);