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Subject[patch 15/76] IRQ_NOPROBE helper functions
-stable review patch.  If anyone has any objections, please let us know.
---------------------
From: Ralf Baechle <ralf@linux-mips.org>

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: Ralf Baechle <ralf@linux-mips.org>
Acked-and-tested-by: Rob Landley <rob@landley.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
include/linux/irq.h | 3 +++
kernel/irq/chip.c | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
--- linux-2.6.24.3.orig/include/linux/irq.h
+++ linux-2.6.24.3/include/linux/irq.h
@@ -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);
--- linux-2.6.24.3.orig/kernel/irq/chip.c
+++ linux-2.6.24.3/kernel/irq/chip.c
@@ -607,3 +607,39 @@ set_irq_chip_and_handler_name(unsigned i
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);
+}
--


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