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genirq: Add return value to check_irq_resend()

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In preparation for an interrupt injection interface which can be used
safely by error injection mechanisms. e.g. PCI-E/ AER, add a return value
to check_irq_resend() so errors can be propagated to the caller.

Split out the software resend code so the ugly #ifdef in check_irq_resend()
goes away and the whole thing becomes readable.

Fix up the caller in debugfs. The caller in irq_startup() does not care
about the return value as this is unconditionally invoked for all
interrupts and the resend is best effort anyway.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lkml.kernel.org/r/20200306130623.775200917@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-03-06 14:03:45 +01:00
parent 008f1d60fe
commit 1f85b1f5e1
3 changed files with 51 additions and 37 deletions
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3
kernel/irq/debugfs.c
View File

@ -218,8 +218,7 @@ static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
err = -EINVAL;
} else {
desc->istate |= IRQS_PENDING;
check_irq_resend(desc);
err = 0;
err = check_irq_resend(desc);
}
raw_spin_unlock_irqrestore(&desc->lock, flags);

2
kernel/irq/internals.h
View File

@ -108,7 +108,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc);
irqreturn_t handle_irq_event(struct irq_desc *desc);
/* Resending of interrupts :*/
void check_irq_resend(struct irq_desc *desc);
int check_irq_resend(struct irq_desc *desc);
bool irq_wait_for_poll(struct irq_desc *desc);
void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action);

83
kernel/irq/resend.c
View File

@ -47,6 +47,43 @@ static void resend_irqs(unsigned long arg)
/* Tasklet to handle resend: */
static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
static int irq_sw_resend(struct irq_desc *desc)
{
unsigned int irq = irq_desc_get_irq(desc);
/*
* Validate whether this interrupt can be safely injected from
* non interrupt context
*/
if (handle_enforce_irqctx(&desc->irq_data))
return -EINVAL;
/*
* If the interrupt is running in the thread context of the parent
* irq we need to be careful, because we cannot trigger it
* directly.
*/
if (irq_settings_is_nested_thread(desc)) {
/*
* If the parent_irq is valid, we retrigger the parent,
* otherwise we do nothing.
*/
if (!desc->parent_irq)
return -EINVAL;
irq = desc->parent_irq;
}
/* Set it pending and activate the softirq: */
set_bit(irq, irqs_resend);
tasklet_schedule(&resend_tasklet);
return 0;
}
#else
static int irq_sw_resend(struct irq_desc *desc)
{
return -EINVAL;
}
#endif
/*
@ -54,50 +91,28 @@ static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
*
* Is called with interrupts disabled and desc->lock held.
*/
void check_irq_resend(struct irq_desc *desc)
int check_irq_resend(struct irq_desc *desc)
{
/*
* We do not resend level type interrupts. Level type
* interrupts are resent by hardware when they are still
* active. Clear the pending bit so suspend/resume does not
* get confused.
* We do not resend level type interrupts. Level type interrupts
* are resent by hardware when they are still active. Clear the
* pending bit so suspend/resume does not get confused.
*/
if (irq_settings_is_level(desc)) {
desc->istate &= ~IRQS_PENDING;
return;
return -EINVAL;
}
if (desc->istate & IRQS_REPLAY)
return;
return -EBUSY;
if (desc->istate & IRQS_PENDING) {
desc->istate &= ~IRQS_PENDING;
desc->istate |= IRQS_REPLAY;
if ((!desc->irq_data.chip->irq_retrigger ||
!desc->irq_data.chip->irq_retrigger(&desc->irq_data)) &&
!handle_enforce_irqctx(&desc->irq_data)) {
#ifdef CONFIG_HARDIRQS_SW_RESEND
unsigned int irq = irq_desc_get_irq(desc);
/*
* If the interrupt is running in the thread
* context of the parent irq we need to be
* careful, because we cannot trigger it
* directly.
*/
if (irq_settings_is_nested_thread(desc)) {
/*
* If the parent_irq is valid, we
* retrigger the parent, otherwise we
* do nothing.
*/
if (!desc->parent_irq)
return;
irq = desc->parent_irq;
}
/* Set it pending and activate the softirq: */
set_bit(irq, irqs_resend);
tasklet_schedule(&resend_tasklet);
#endif
}
if (!desc->irq_data.chip->irq_retrigger ||
!desc->irq_data.chip->irq_retrigger(&desc->irq_data))
return irq_sw_resend(desc);
}
return 0;
}