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Commit 46f4f8f6 authored by Ralf Baechle's avatar Ralf Baechle Committed by Linus Torvalds
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IRQ_NOPROBE helper functions 



Probing non-ISA interrupts using the handle_percpu_irq as their handle_irq
method may crash the system because handle_percpu_irq does not check
IRQ_WAITING.  This for example hits the MIPS Qemu configuration.

This patch provides two helper functions set_irq_noprobe and set_irq_probe to
set rsp.  clear the IRQ_NOPROBE flag.  The only current caller is MIPS code
but this really belongs into generic code.

As an aside, interrupt probing these days has become a mostly obsolete if not
dangerous art.  I think Linux interrupts should be changed to default to
non-probing but that's subject of this patch.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Acked-and-tested-by: default avatarRob Landley <rob@landley.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 922f9cfa

include/linux/irq.h

+3 −0
Original line number Diff line number Diff line
@@ -367,6 +367,9 @@ set_irq_chained_handler(unsigned int irq, 
	__set_irq_handler(irq, handle, 1, NULL);

}



extern void set_irq_noprobe(unsigned int irq);

extern void set_irq_probe(unsigned int irq);



/* Handle dynamic irq creation and destruction */

extern int create_irq(void);

extern void destroy_irq(unsigned int irq);

kernel/irq/chip.c

+36 −0
Original line number Diff line number Diff line
@@ -589,3 +589,39 @@ set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip, 
	set_irq_chip(irq, chip);

	__set_irq_handler(irq, handle, 0, name);

}



void __init set_irq_noprobe(unsigned int irq)

{

	struct irq_desc *desc;

	unsigned long flags;



	if (irq >= NR_IRQS) {

		printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);



		return;

	}



	desc = irq_desc + irq;



	spin_lock_irqsave(&desc->lock, flags);

	desc->status |= IRQ_NOPROBE;

	spin_unlock_irqrestore(&desc->lock, flags);

}



void __init set_irq_probe(unsigned int irq)

{

	struct irq_desc *desc;

	unsigned long flags;



	if (irq >= NR_IRQS) {

		printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);



		return;

	}



	desc = irq_desc + irq;



	spin_lock_irqsave(&desc->lock, flags);

	desc->status &= ~IRQ_NOPROBE;

	spin_unlock_irqrestore(&desc->lock, flags);

}